WO2016119032A1 - Repulpable adhesives for cellulosic substrates obtained by cellulose solubilisation or plasticising, and uses thereof - Google Patents

Repulpable adhesives for cellulosic substrates obtained by cellulose solubilisation or plasticising, and uses thereof Download PDF

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Publication number
WO2016119032A1
WO2016119032A1 PCT/BR2016/050011 BR2016050011W WO2016119032A1 WO 2016119032 A1 WO2016119032 A1 WO 2016119032A1 BR 2016050011 W BR2016050011 W BR 2016050011W WO 2016119032 A1 WO2016119032 A1 WO 2016119032A1
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cellulose
adhesive
adhesives
paper
adhesive according
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PCT/BR2016/050011
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French (fr)
Portuguese (pt)
Inventor
Fernando Galembeck
Elisa SILVA FERREIRA
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Centro Nacional De Pesquisa Em Energia E Materiais
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Publication of WO2016119032A1 publication Critical patent/WO2016119032A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/02—Cellulose; Modified cellulose
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J101/00—Adhesives based on cellulose, modified cellulose, or cellulose derivatives
    • C09J101/02—Cellulose; Modified cellulose

Definitions

  • the present invention relates to adhesives produced by solubilizing or plasticizing cellulose or pulps from mostly cellulose biomedical sources, which are applied for the sizing or surface finishing of dry or wet cellulosic substrates.
  • cellulose comprises and represents the cellulose polymer in its pure form, registered under CAS Number 9004-34-6.
  • cellulose as used herein, different crystalline forms of the polymer are comprised, including micro and nanocrystalline celluloses, and macro, micro or nanofiber arrangements of different dimensions and aspect ratios.
  • cellulose pulp comprises and represents the substance of CAS Number 65996-61-4, defined as a fibrous material obtained by treating lignocellulosic biomedical sources of different origins with one or more aqueous pulping solutions and / or bleaching chemicals.
  • the pulp is mainly composed of cellulose and may contain hemicellulose, lignin and other components to a lesser extent. The relative amounts of these minority components depend on the extent of the pretreatment, pulping and bleaching processes applied on biomedical sources.
  • the products of this invention are preferably applied to paper, cardboard, cartons, packaging and the like and may be applied to other types of materials.
  • substrates from cellulosic sources such as fibers and fabrics.
  • Adhesives are fully repulpable and allow glued substrates to be reprocessed with high operability and efficiency, especially paper reprocessing.
  • the process used for the production of the adhesives consists of a set of steps that allows those skilled in the art to produce different embodiments of the present invention, also capable of being incorporated into the paper and allowing its full repulpability. Further, the present invention comprises the production of such repulpable adhesives in liquid, paste or tape form.
  • the choice of the best adhesive for bonding cellulosic substrates may involve analyzes that go beyond the very needs to be met and the performance of adhesive joints for the strength and durability of bonding promoted by the adhesive, especially when involving cost and sustainability issues.
  • adhesives have an unfavorable effect on the paper recycling process as they negatively interfere with pulp formation.
  • the hydrophobic property of adhesives is a major cause of what is called a "sticky white field,” meaning that during the hot reprocessing process, adhesives often deposit on hot, moving parts of paper machines, leading to machine shutdowns and process interruption. This problem is especially serious not only in reprocessors, but in the paper mills themselves, where tearing occurs in the sheets and rolls that require emergency splicing, and the spliced material must eventually be repossessed.
  • the same problem occurs in the production of labels and in the bonding of cartons, cardboard and other cellulosic derivatives, whose recycling and final pulp composition are also impaired due to the difficulty in removing the used adhesives.
  • US 14 / 211,132 (published under US 20140272352) describes the addition of inorganic nanoparticles, especially clay, to polyolefin resins to promote the adhesion of layers of cellulosic substrates forming repulpable composites.
  • US 6,242,593 describes the manufacture of biodegradable and repulpable adhesives from vinyl monomer copolymers and alkyl polyglycoside maleic acid esters.
  • the adhesive production methodology proposed in this invention differs from those disclosed in these documents in that it has only cellulose as its raw material, not comprising other polymers, modified celluloses or cellulose derivatives.
  • aqueous based adhesive solutions are limited because of its compatibility with the adhesive and the final application of the bonded material.
  • an aqueous solution of carboxymethylcellulose free of any additives that may have a potential for toxicity to the smoker.
  • the additive to be chosen must still be fully water soluble, compatible with the cellulosic base and not destabilize the solution formed. Additives may still come at an additional cost to prepare solutions.
  • solutions composed of a specific polymer perform well as adhesives for joining parts and parts made of the same polymer.
  • the ideal adhesive for 100% repulpable paper will be an aqueous cellulose solution.
  • cellulose is notoriously insoluble in water and in the vast majority of known low environmental impact liquids, which makes obtaining this solution a challenge.
  • the solution will need to be free of impurities or additives that negatively interfere with substrate reprocessing and repulping.
  • soluble cellulose-derived polymers that are widely used in industry today, such as: (i) hydroxyethylcellulose, commonly used, (ii) cellulose acetate butyrate, mainly used for bonding between papers of different compositions and papers in plastics, (iii) methylcellulose, applied on cellulosic substrates when the wrinkling effect is to be minimized and (iv) ethylcellulose, suitable for bonding cellulosic substrates at low temperatures.
  • the aforementioned soluble cellulose polymers concentrate on the aqueous effluents generated by the recycling process, contributing to the increased biochemical oxygen demand of the effluents and interfering with the flocculation processes used for their treatment.
  • adhesives derived from cellulose and other carbohydrates are used in the paper and textile industries as binders and functional additives. In this class of adhesives, adhesion is promoted by evaporation or diffusion of solvent, aqueous or not.
  • This invention discloses a process comprising a set of steps that allow the solubilization or plasticization of cellulose or pulps from predominantly cellulose-based biomassic sources.
  • the main step of the process comprises mechanical shearing of the starting material under low temperature in aqueous medium and alkaline conditions.
  • pulp and pulp from properly treated lignocellulosic biome sources can be used directly as a starting material for the production of adhesives. They perform well in bonding dry or wet paper, forming joints that are more resistant to mechanical stress than the actual sheets bonded in the presence of other adhesives.
  • a significant advantage of this invention is that papers and other cellulosic substrates on which the adhesives of the present invention were applied were subject to reprocessing and repulping in their entirety, solving a state-of-the-art technological problem.
  • the adhesives presented in this invention have significant potential for immediate applicability by the papermaking and papermaking industries and other biomechanical sources mainly composed of cellulose and for substitution total or partial adhesives used by these sectors.
  • This invention relates to repulpable adhesives produced by solubilizing or plasticizing cellulose or pulps from other lignocellulosic biomedical sources predominantly composed of cellulose, through a set of process steps whose main step is the shear of the starting material in alkaline aqueous medium under low temperature.
  • the resulting adhesives can be applied to the surface of paper and other cellulosic substrates with different moisture contents, from totally dry to fully wet.
  • the adhesives of the present invention provide good sizing efficiency only with the presence of cellulose in its composition, without the need to add the formulation with ethers, esters or other cellulose derivatives, or other synthetic polymer bases such as polyvinyl alcohol, vinyls, acrylates, vinyl acrylics, styrene acrylics, cyanoacrylates, aminoacrylates, styrene butadiene resins and isoprene acrylic resins, among other known polymers used in the art as water based adhesive components.
  • synthetic polymer bases such as polyvinyl alcohol, vinyls, acrylates, vinyl acrylics, styrene acrylics, cyanoacrylates, aminoacrylates, styrene butadiene resins and isoprene acrylic resins, among other known polymers used in the art as water based adhesive components.
  • the starting materials of the present invention are celluloses of varying degrees of purity, crystallinity and aspect ratio which can be efficiently solubilized or plasticized by the process steps described herein and result in adhesives which may be applied over cellulosic substrates in the form of solutions, pastes or other physical forms.
  • cellulose based adhesives proposed in this invention can still be significantly improved by incorporating into the medium during the adhesive production process additives such as: metal oxides, alcohols and glycerols, cationic, anionic and nonionic surfactants, alkali metal soaps, clays and miscellaneous nanoparticles which may function as plasticizers or reinforcing agents to improve adhesion of the additive to the substrate, among other compound possibilities.
  • additives such as: metal oxides, alcohols and glycerols, cationic, anionic and nonionic surfactants, alkali metal soaps, clays and miscellaneous nanoparticles which may function as plasticizers or reinforcing agents to improve adhesion of the additive to the substrate, among other compound possibilities.
  • the adhesive joints obtained from the adhesives produced in this invention are 100% repulpable. Pulp produced after reprocessing these joints, or the substrates containing these joints, is not distinguishable from a pulp obtained with the same paper in the absence of adhesive.
  • the excellent performance of the adhesives produced in this invention has been proven by performing mechanical strength tests under controlled conditions of adhesive joints produced by bonding different substrates by different adhesive solution formulations produced by the process stepset of this invention. All adhesive joints glued by the solutions withstood the test conditions. Tearing and failures occurred in regions outside the adhesive joints.
  • Figure 1 is a photographic image showing the behavior of the adhesive joints of 12 specimens subjected to mechanical strength testing under controlled conditions.
  • the specimens were produced by gluing 24 strips of filter paper two by two with an aqueous adhesive solution produced by the present invention.
  • Figure 2 is a schematic representation of the reconstruction of a filter paper bonded with an adhesive solution produced by the present invention obtained by X-ray microtomography.
  • Figures 3A and 3B are photographic images showing the decantation of the pulp from strips of the same filter paper which were glued together and then triturated with water.
  • Figure 3A shows the pulp decantation of 5 pairs of commercial filter paper strips previously bonded with a polyvinyl acetate-based adhesive, commercially known as PVA latex.
  • Figure 3B shows the decantation of the pulp from 5 pairs of strips of the same filter paper previously pasted with an alkaline aqueous cellulose solution prepared according to Example 1 of the present invention.
  • Figure 3C shows the result of grinding and repulping the reference sample, ie the filter paper without the addition of adhesives.
  • Figures 4A, 4B and 4C are photographic images showing modes of application of the adhesive produced in the present invention as a solution on a commercial filter paper substrate.
  • Figure 4A shows the application of the adhesive solution to the end of a paper strip to delimit the region of the adhesive joint.
  • Figure 4B shows the union of two strips at their ends, forming the specimen.
  • Figure 4C shows the specimen joined by the adhesive joint after applying compressive force, ready to be dried.
  • FIGURE 3 is a photographic image of 24 strips of same size filter paper bonded two by two with an aqueous adhesive solution composed of 5 wt% cellulose and 7 wt% NaOH which was prepared by treatment. thermal and mechanical.
  • the 12 bonded specimens were conditioned at 23 ⁇ 2 ° C and 50 ⁇ 5% humidity for 48 h and submitted to a tensile test with a speed of 1.25 mm / min and a working length of 140 mm. In each specimen, a maximum tension identical to that of a single paper strip (12 mPa) was obtained.
  • Figure 1 shows that in all specimens the rupture of the substrate under controlled traction occurred in a distinct region of the adhesive joint, showing that the joint glued by the adhesive solution is stronger than the paper itself.
  • Figure 4 is a schematic representation of the X-ray microtomography of the reconstruction of a filter paper bonded with an adhesive solution produced according to the preparation described in Example 1 of this invention.
  • the blue dots in the image indicate regions of higher X-ray attenuation, that is, of higher electron density. This effect occurs mainly by the presence of sodium ions in the adhesive.
  • Figure 2 shows that the adhesive solution applied to the substrate fills the gaps between the paper fibers, rather than preferably spreading over the surface of the sheets and forming an adhesive film therebetween.
  • Figures 3A and 3B are photographic images showing pulps obtained after repulping the region of the adhesive joint of strips of the same filter paper which have been bonded together.
  • Figure 3A shows a pulp obtained by grinding 5 specimens. composed of two strips of commercial filter paper previously bonded with a polyvinyl acetate-based adhesive, commercially known as PVA latex. The final pH of this dispersion was 5.
  • Figure 3B shows a pulp obtained by grinding 5 specimens of the same commercial filter paper composed of two strips bonded with an alkaline aqueous cellulose solution prepared according to Example 1 of this invention. The final pH of this dispersion was 6.
  • Figure 3C shows the result of grinding and repulping the reference sample, ie the same commercial filter paper without the addition of adhesives.
  • the crushed area was the same size as the adhesive joint areas of the test specimens of Figures 3A and 3B.
  • This dispersion was pH 5.
  • the repulping process for preparations 3A, 3B and 3C was similar and comprised grinding the joints in a blender in the presence of 100 ml of water and decanting the pulp under rest for 30 minutes.
  • Figure 3B shows that the dispersion containing the specimen adhesive joint pulp glued by the adhesive solution produced in the present invention is completely decanted, as well as the dispersion of the reference sample (Figure 3C).
  • Figure 4A is a photographic image showing an adhesive solution composed of 5 mass% commercial qualitative filter paper and 7 mass% NaOH prepared according to the steps described in this invention. manually applied by means of a glass laminate over the end of a commercial qualitative filter paper strip 10.0 cm x 2.5 cm x 0.12 cm. The end of the 1 cm x 2.5 cm dry strip was covered with 40 mg of the adhesive solution.
  • Figure 4B shows the specimen after joining the ends of two strips prepared according to the procedure described in Figure 4A.
  • Figure 4C shows the specimen after the application of compressive force of approximately 700 N for 5 s over the bonded region forming the adhesive joint.
  • the repulpable adhesives presented in this invention solve usual and undesirable problems in the manufacture of cellulosic derivatives, especially in the production of paper, facilitating the complete recycling and repulping of cellulosic substrates after use.
  • Adhesives commonly used in the manufacture of paper and cardboard artifacts have excellent mechanical properties, but create a problem when they are once again made into cellulosic pulp as they form a water-insoluble sludge that contaminates the pulp. This operational problem is known in the state of the art and cited by several authors, such as Venditti, Lucas and Jameel. Adhesive deposits clog the mesh used in the process, leading to reduced production speed, paper defects and printing problems.
  • the present invention discloses adhesives produced by solubilization or plasticization of cellulose or cellulose pulp obtained by treating different biomassic sources using a set of production steps under controlled conditions that include the mechanical mixing of the cellulosic solid and the alkaline liquid and cooling of this mixture to increase the solubility of the cellulose or its swelling.
  • the repulpable adhesives of the present invention comprise from 0.5% to 35% by weight of cellulose (CAS Number 9004-34-6) or pulp mainly composed of cellulose (CAS Number 65996-61-4), wholly or partially. solubilized in a solvent medium, and from 1% to 10% by weight of one or more alkalis, totally or partially solubilized in the solvent medium.
  • Said one or more alkalis are selected from a group comprising sodium, potassium, lithium, calcium and ammonium hydroxides, tetramethylammonium, or alkali metal aluminates and zincates.
  • the repulpable adhesives of the present invention optionally comprise one or more additives in a concentration of 0% to 30% by weight, totally or partially solubilized in the solvent medium.
  • the resulting solution or paste adhesive is applied to the surfaces of the cellulosic substrate forming adhesive joints that will be glued as lap joints, or joint joints, or as butt joints, or butt joints.
  • adhesive joints that will be glued as lap joints, or joint joints, or as butt joints, or butt joints.
  • the polymer predominantly present in the composition in the adhesive is cellulose (CA Number 9004-34-6), it is incorporated into the pulp and does not impair its formation or contaminate it with undesirable impurities, thus enabling full repulping of the substrate.
  • the adhesive is produced by mixing an alkaline cellulose solution or dispersion with a neutralizing solid additive.
  • a neutralizing solid additive such as sodium bicarbonate, borax, boric acid or any other buffering substance at neutral pH, to avoid handling a strongly alkaline solution while bonding the paper.
  • the adhesive is produced by adding to the alkaline cellulose solution a hydrotropic additive such as urea, thiourea, mono-, di- and triethanolamines, glycerol, ethanol and other alcohols, dimethyl sulfoxide, toluenesulfonates, xylenesulfonates. , cumenesulfonates, lignosulfonates, benzoates, salicylates, citrates, acetates and other compounds known in the art.
  • a hydrotropic additive such as urea, thiourea, mono-, di- and triethanolamines, glycerol, ethanol and other alcohols, dimethyl sulfoxide, toluenesulfonates, xylenesulfonates. , cumenesulfonates, lignosulfonates, benzoates, salicylates, citrates, acetates and other compounds known in the art.
  • the alkaline cellulose solution or dispersion is added with zinc, aluminum, vanadium, tin and germanium oxides.
  • the alkaline cellulose solution or dispersion is added with alkaline compounds such as lithium hydroxide, potassium, ammonium and tetramethylammonium and calcium oxide.
  • the alkaline cellulose solution or dispersion is added with an anionic, cationic or nonionic surfactant dispersant.
  • the alkaline cellulose solution or dispersion is additive with clay nanoparticles, metal oxides, carbonates, phosphates or silicates, which act as reinforcing agents in the bonding of thick cardboard or paperboard parts or sheets. , improving the mechanical properties of the adhesive itself.
  • Joint drying occurs by simple evaporation It can be accelerated by heating using any method known in the art, as well as by forced air circulation or exposure to a drier.
  • the adhesives of the present invention have various uses and applications, such as:
  • Applying the adhesives to dry or wet paper or cardboard is done using any method or device known in the art, and once dry, the adhesive resists controlled mechanical tensile, twisting, tearing and peeling efforts with superior performance. to the very sheets of paper or cardboard used in forming the joint.
  • the adhesive is prepared in solution by the total solubilization of 5% (w / w) commercially available high purity microcrystalline cellulose from cotton linter in a 7% (w / w) solution. / m) NaOH in water.
  • the cellulose is slowly added to the aqueous NaOH solution and homogenized at 0 ° C and 6000 rpm for 10 minutes.
  • the resulting solution is cooled on standing at -20 ° C for 1 h.
  • the adhesion efficiency of the adhesive solution is verified by performing a sizing test. Said test begins by applying a 40 mg layer of the adhesive solution at 24 2 C over an area of 1 cm x 2.5 cm of a commercial grade dry weight 80 g / m 2 filter strip and 10.0 cm x 2.5 cm x 0.12 cm, completely covering the application area. After application of the adhesive to the strip, the faces of this strip and a dry strip of paper without adhesive were joined under compressive strength of approximately 700 N for 5 s. The drying of Glued specimen, placed on a polyethylene (PE) film, was held at 24 ° C and approximately 40% humidity for 90 min. This procedure was repeated to generate 11 more specimens.
  • PE polyethylene
  • the adhesion efficiency was evaluated for the 12 specimens by mechanical tensile test under controlled conditions.
  • the specimens were conditioned at 23 ⁇ 2 ° C and 50 ⁇ 5% humidity for 48 h. A speed of 1.25 mm / min and a working length of 140 mm was applied to the specimens, giving the maximum tension identical to that of a single strip of filter paper (12 MPa).
  • the adhesive joints subjected to the test conditions proved to be tensile resistant.
  • the disruption of all specimens always occurred in a region other than the glued area, showing that the adhesive joint is stronger than the paper itself ( Figure 1).
  • Glued regions from randomly selected specimens were selected for analysis by X-ray microtomography (Figure 2) to evaluate the bonding efficiency.
  • the performance of the adhesive solution on repulping was evaluated from an assay that simulated reprocessing of the bonded substrates.
  • Five bonded specimens were repulped by grinding in a blender with the addition of 100 ml of water.
  • Controls selected for repulping efficiency comparison criteria were strips of filter paper without adhesive and 5 specimens of the same filter paper bonded with a commercial PVA latex adhesive. The crushed suspensions were decanted at rest for 30 minutes, obtaining similar looking pulps in both the bonded material and the control.
  • This embodiment of the invention differs from Example 1 in the form of application of the adhesive and the surface covered by the adhesive on the substrate.
  • the adhesive solution is prepared following exactly the procedure of Example 1, but the adhesive solution is applied to commercial grade 80 g / m 2 qualitative filter paper strips of 10.0 cm x 2.5 cm x 0 size. , 12 cm whose ends have been torn. 2 mm of the torn end of each strip was immersed in the adhesive solution and the two strips were glued together by joining its adhesive-covered ends.
  • the adhesion and drying parameters of the bonded strips and the tensile test parameters were similar to those described in example 1. In this embodiment, the adhesive joints glued by the torn ends proved to be tensile resistant under the test conditions.
  • This embodiment of the invention differs from Example 1 in the moisture of the substrate where bonding occurs.
  • bonding occurs on damp sheets of sulfite paper.
  • the adhesive solution is prepared by total solubilization of 2%. (w / w) microcrystalline cellulose in a solution of 2.8% (w / w) NaOH in water, and following the same methodology as Example 1. Sizing was performed by applying 25 mg of the adhesive solution to strips of 75 g / m 2 damp sulfite paper, 10.0 cm x 2.5 cm x 0.12 cm in size, covering an area of 1 cm x 2.5 cm of the paper strip. The strips of paper contained on average 60% humidity. After application of the adhesive solution, the joining of the faces between two strips was performed as described in Example 1. The drying of the specimens was performed at 24 ° C and approximately 40% humidity for 180 min on a PE film. In this mode, all adhesive joints of the samples proved to be tensile resistant when subjected to controlled mechanical testing conditions.
  • This embodiment of the invention differs from the previous examples in that the adhesive is produced in paste form and the sizing is performed on damp sheets of the commercial qualitative filter paper used in Example 1.
  • the adhesive paste produced in this example is proportionally richer in cellulose. than the adhesive solutions disclosed in Examples 1, 2, 3, 5, 6, 7 and 8 of this invention.
  • the adhesive paste is prepared by partially solubilizing 20% (w / w) microcrystalline cellulose in a 7% (w / w) solution of NaOH in water. The alkaline solution was cooled to 0 C and 2 the pulp was added to this solution slowly and under low shear stirring. The homogenization extended for 10 minutes and at the end the dispersion was cooled at rest at -20 2 C for 1h, generating the opaque adhesive paste.
  • Bonding was performed by applying a single 25 mg layer of the adhesive paste at 24 2 C over an area of 1 cm x 2.5 cm of the wet strips of 80 g / m 2 qualitative weight filter paper of 10, 0 cm x 2.5 cm x 0.12 cm. The strips of paper contained on average 60% humidity.
  • the joining of the faces of two strips was performed following the same procedure as Example 1.
  • the drying of the samples was performed following the procedure of Example 3. In this embodiment, all the adhesive joints of the samples proved to be resistant to traction when subjected to controlled mechanical test conditions.
  • Example 1 is repeated but the commercial qualitative filter paper is replaced with dry sulfite paper sheets. In this mode, all adhesive joints of the samples proved to be tensile resistant when subjected to controlled mechanical testing conditions.
  • This embodiment of the invention differs from the previous examples in that the adhesive solution is prepared by the direct dissolution of 5% (w / w) commercial grade 87 g / m 2 filter paper with a minimum concentration of 98% (w / w). ) in cellulose and without starch, in a solution of 7% (w / w) NaOH in water.
  • the temperature and agitation parameters for solubilization are the same. Bonding was performed by applying 25 mg of the adhesive solution over an area of 1 cm x 2.5 cm strips of qualitative filter paper weighing 80 g / m 2 and 10.0 cm x 2 in size. 5 cm x 0.12 cm.
  • the filter paper sheets contained an average of 60% humidity. Face joining was performed following the same procedure as Example 1 under compressive strength of approximately 700 N for 5 s and drying was performed following the same procedure as Example 3. In this embodiment, all adhesive joints of the samples were tensile resistant when subjected. controlled mechanical test conditions.
  • the adhesive solution is prepared by dissolving 5% (w / w) of commercially available high purity microcrystalline cellulose from cotton linter in a 7% (w / w) solution of 12% NaOH in water. (m / m) of urea. The cellulose is added to the aqueous solution of NaOH and urea and homogenized at 0 ° C and 6000 rpm for 10 min. The bonding was performed by applying a 40 mg layer of the adhesive solution over a 1 cm x 2 cm area of a 5.0 cm x 2.0 cm commercially known poplin strip of fabric covering the entire area. of application.
  • the adhesive-coated fabric strip was joined with a 75 g / m 2 bond of sulfite paper of the same size.
  • the faces were joined under force approximately 1000 N for 10 s.
  • the glued specimen was dried at 24 ° C and approximately 40% humidity for 90 min, placed on a PE film.
  • a 40 mg layer of adhesive was applied to the outer surface of the fabric on the adhesive joint and heat treated at 60 ° C and saturated humidity for 30 min.
  • the final drying of the specimen was performed at 24 ° C and approximately 40% humidity for 90 min, placed on a PE film. In this mode, all adhesive joints of the samples proved to be tensile resistant when subjected to controlled mechanical testing conditions.
  • This embodiment of the invention differs from the previous examples in that the starting material used in the preparation of the adhesive solution.
  • the adhesive solution was made from sugarcane bagasse pulp, previously prepared by heat treatment of the bagasse at 130 ° C in 3% (w / v) aqueous NaOH solution for 3 h.
  • the sugarcane bagasse wet pulp (humidity 67%) was dispersed in an aqueous NaOH solution, obtaining a dispersion of 5% (w / w) bagasse pulp and 7% (w / w) NaOH.
  • the temperature and stirring parameters for homogenization were the same as described in Example 1.
  • the supernatant of this dispersion was separated by centrifugation at 10,000 rpm for 5 min.
  • the bonding was performed by applying 50 ⁇ L of the liquid phase over an area of 1 cm x 2.5 cm of wet strips of 80 g / m 2 qualitative filter paper with a size of 10.0 cm x 2.5 cm x 0. .12 cm.
  • the filter paper sheets contained an average of 60% humidity.
  • the junction of Faces were performed following the same procedure as Example 1 under compressive strength of approximately 700 N per 5 s and drying was performed following the same procedure as Example 3. In this embodiment, all adhesive joints of the samples were tensile strength when subjected to controlled conditions. of mechanical tests.

Abstract

The invention relates to repulpable adhesives for use on cellulosic substrates, such as paper, fibres and fabrics, promoting adhesion and other surface properties. The main embodiment of the invention consists of an adhesive solution composed mainly of cellulose (CA Number 9004-34-6) solubilised in an alcaline aqueous medium with or without additives. The adhesive solutions and pastes produced according to this invention are used for gluing both dry and wet substrates, forming adhesive joints of different geometries which impart excellent mechanical resistance to the glued surfaces. The parts glued or coated with the adhesives produced by the method according to this invention can be entirely repulped in water by simple mechanical action, producing pulps that are indistinguishable from those obtained from the same substrates without any adhesives. The adhesives proposed by this invention offer a promising alternative to the adhesives based on synthetic polymers, which are normally used by the cellulose processing and transforming industries, and ensure sustainable reprocessing of cellulose pulps.

Description

ADESIVOS REPOLPAVEIS PARA SUBSTRATOS CELULÓSICOS, OBTIDOS POR SOLUBILIZAÇÃO OU PLASTIFICAÇÃO DE CELULOSE, E SEUS USOS CELULOSTIC SUBSTRATES, REPOLPABLE STICKERS OBTAINED BY CELLULOSE SOLUBILIZATION OR PLASIFICATION, AND THEIR USES
CAMPO DA INVENÇÃO FIELD OF INVENTION
[001] A presente invenção se refere a adesivos produzidos pela solubilização ou plastificação de celulose ou de polpas de fontes biomássicas majoritariamente constituídas por celulose, que são aplicados para a colagem ou acabamento superficial de substratos celulósicos secos ou úmidos .  [001] The present invention relates to adhesives produced by solubilizing or plasticizing cellulose or pulps from mostly cellulose biomedical sources, which are applied for the sizing or surface finishing of dry or wet cellulosic substrates.
[002] Nesta invenção, "celulose" compreende e representa o polímero de celulose em sua forma pura, registrado sob o CAS Number 9004-34-6. Dentro da denominação "celulose" aqui empregada, estão compreendidas diferentes formas cristalinas do polímero, incluindo celuloses micro e nanocristalinas , e arranjos de macro, micro ou nanofibras de diferentes dimensões e razões de aspecto.  In this invention, "cellulose" comprises and represents the cellulose polymer in its pure form, registered under CAS Number 9004-34-6. Within the term "cellulose" as used herein, different crystalline forms of the polymer are comprised, including micro and nanocrystalline celluloses, and macro, micro or nanofiber arrangements of different dimensions and aspect ratios.
[003] Nesta invenção, "polpa de celulose" compreende e representa a substância de CAS Number 65996-61-4, definida como um material fibroso obtido pelo tratamento de fontes biomássicas lignocelulósicas de diferentes origens com uma ou mais soluções aquosas de polpação e/ou produtos químicos para branqueamento. A polpa é composta majoritariamente por celulose e pode conter hemicelulose, lignina e outros componentes em menor proporção. Os montantes relativos desses componentes minoritários dependem da extensão dos processos de pré-tratamento, polpação e branqueamento aplicados sobre as fontes biomássicas.  In this invention, "cellulose pulp" comprises and represents the substance of CAS Number 65996-61-4, defined as a fibrous material obtained by treating lignocellulosic biomedical sources of different origins with one or more aqueous pulping solutions and / or bleaching chemicals. The pulp is mainly composed of cellulose and may contain hemicellulose, lignin and other components to a lesser extent. The relative amounts of these minority components depend on the extent of the pretreatment, pulping and bleaching processes applied on biomedical sources.
[004] Os produtos desta invenção são aplicados preferencialmente em papel, papelão, cartões, embalagens e similares, podendo ainda ser aplicados em outros tipos de substratos provenientes de fontes celulósicas, como fibras e tecidos. The products of this invention are preferably applied to paper, cardboard, cartons, packaging and the like and may be applied to other types of materials. substrates from cellulosic sources such as fibers and fabrics.
[005] Os adesivos são totalmente repolpáveis e permitem que os substratos colados possam ser reprocessados com alta operacionalidade e eficiência, com destaque para o reprocessamento de papéis.  [005] Adhesives are fully repulpable and allow glued substrates to be reprocessed with high operability and efficiency, especially paper reprocessing.
[006] O processo usado para produção dos adesivos é constituído por um conjunto de etapas que permite aos versados no estado da arte produzir diferentes modalidades da presente invenção, também capazes de se incorporar ao papel e permitir a total repolpabilidade do mesmo. Ainda, a presente invenção compreende a produção destes adesivos repolpáveis na forma líquida, de pasta ou em fitas.  The process used for the production of the adhesives consists of a set of steps that allows those skilled in the art to produce different embodiments of the present invention, also capable of being incorporated into the paper and allowing its full repulpability. Further, the present invention comprises the production of such repulpable adhesives in liquid, paste or tape form.
FUNDAMENTOS DA INVENÇÃO BACKGROUND OF THE INVENTION
[007] Papéis, papelões e embalagens de diferentes composições celulósicas são colados com facilidade pela ação de adesivos à base de diferentes substâncias químicas. Adesivos também são empregados em substratos celulósicos para fornecer propriedades específicas às suas superfícies como resistência à água e a líquidos orgânicos, aumento ou redução de brilho, rigidez, reforço da capacidade de tingimento, ajuste de porosidade e de rugosidade da superfície, entre outras propriedades físico-químicas e dimensionais, sendo nesta aplicação denominados ligantes ou agentes de sizing.  [007] Paper, cardboard and packaging of different cellulosic compositions are easily glued by the action of adhesives based on different chemicals. Adhesives are also employed on cellulosic substrates to provide surface specific properties such as water and organic liquid resistance, increase or decrease in gloss, stiffness, enhanced dyeing capacity, surface porosity and roughness adjustment, among other physical properties. - chemical and dimensional, in this application being called binders or sizing agents.
[008] A escolha do melhor adesivo para unir substratos celulósicos pode envolver análises que vão além das próprias necessidades a serem atendidas e do desempenho das juntas adesivas quanto à robustez e durabilidade da ligação promovida pelo adesivo, especialmente quando envolvem questões de custo e de sustentabilidade. [008] The choice of the best adhesive for bonding cellulosic substrates may involve analyzes that go beyond the very needs to be met and the performance of adhesive joints for the strength and durability of bonding promoted by the adhesive, especially when involving cost and sustainability issues.
[009] Quanto à sustentabilidade, os mercados industriais de papel e de embalagens substituíram progressivamente o emprego de adesivos à base de solventes orgânicos por adesivos à base de água, reduzindo a exposição dos trabalhadores a voláteis orgânicos potencialmente tóxicos. Sob o ponto de vista operacional, esta mesma substituição facilitou o processo de reciclagem, dispensando a necessidade da separação e recuperação dos solventes e estendendo o ciclo de vida dos produtos.  [009] As for sustainability, the industrial paper and packaging markets have progressively replaced the use of organic solvent based adhesives with water based adhesives, reducing workers' exposure to potentially toxic organic volatiles. From an operational point of view, this same replacement facilitated the recycling process, eliminating the need for solvent separation and recovery and extending the life cycle of products.
[0010] Geralmente, adesivos têm efeito desfavorável no processo de reciclagem dos papéis, uma vez que interferem negativamente na formação da polpa. A propriedade hidrofóbica dos adesivos constitui uma das principais causas do que é chamado "campo branco pegajoso", ou seja, durante o processo de reprocessamento a quente dos papéis, os adesivos frequentemente se depositam em partes quentes e móveis das máquinas de papel, levando a paradas de máquinas e interrupção do processo. Esse problema é especialmente sério não só nos reprocessadores , mas nas próprias fábricas de papel, onde eventualmente ocorrem rasgos nas folhas e rolos que demandam emendas emergenciais , e o material emendado devendo ser eventualmente repolpado. O mesmo problema ocorre na produção de etiquetas e na colagem de cartões, papelões e outros derivados celulósicos, cuja reciclagem e composição final da polpa também são prejudicadas devido à dificuldade na remoção dos adesivos utilizados .  Generally, adhesives have an unfavorable effect on the paper recycling process as they negatively interfere with pulp formation. The hydrophobic property of adhesives is a major cause of what is called a "sticky white field," meaning that during the hot reprocessing process, adhesives often deposit on hot, moving parts of paper machines, leading to machine shutdowns and process interruption. This problem is especially serious not only in reprocessors, but in the paper mills themselves, where tearing occurs in the sheets and rolls that require emergency splicing, and the spliced material must eventually be repossessed. The same problem occurs in the production of labels and in the bonding of cartons, cardboard and other cellulosic derivatives, whose recycling and final pulp composition are also impaired due to the difficulty in removing the used adhesives.
[0011] Como citado, devido à necessidade de controle fino no processo de produção do papel para evitar danos em sua superfície, e considerando a tecnologia em equipamentos e instalações presentemente empregada para aplicação das soluções adesivas, é altamente desejável que a escolha do melhor adesivo para colagem do substrato seja feita com base na formulação que venha a garantir a ideal processabilidade operacional . As mentioned, due to the need for fine control in the paper production process to avoid damage to your paper. Considering the technology in equipment and installations currently employed for the application of adhesive solutions, it is highly desirable that the choice of the best substrate bonding adhesive be made on the basis of the formulation that ensures optimum operational processability.
[0012] Relatos de autores versados na colagem de derivados celulósicos indicam que o processo de colagem de celulose úmida oferece muitas dificuldades para uma execução bem sucedida. Robert Pelton, uma autoridade internacional na arte, em relação a este fato, declara em Microgel adhesive for wet cellulose : measurements and modeling (artigo publicado na Langmuir, em 2012), que "celulose úmida é um substrato desafiador" . Para a colagem de celulose úmida, em geral são necessários adesivos de alta complexidade e especificamente desenvolvidos para essa finalidade, tais como polivinilaminas em microgéis de poli-N- isopropilacrilamida . Outros sistemas poliméricos para esta finalidade podem ser menos complexos, porém os seus processos de colagem compreendem etapas que resultam em desvantagens operacionais. Um destes casos é descrito na patente US 7,294,670, onde uma dispersão aquosa de resina de poliuretano é usada para adesão na laminação de papel molhado e seco, porém esta colagem demanda uma necessária etapa de cura. Contudo, os adesivos que são produtos da invenção aqui descrita são de baixa complexidade, tanto na sua composição quanto com relação ao seu processo produtivo, e diferentemente dos adesivos acima relatados, apresentam a capacidade de colar substratos celulósicos úmidos com ótima eficiência . [0013] Foram encontrados documentos no estado da técnica que revelam processos de produção de adesivos que tratam da repolpagem de substratos celulósicos. O pedido US 14/083,286 (publicado sob o número US 20140120277) descreve adesivos repolpáveis à base de monômeros ou polímeros acrílicos e PET modificado. O pedido US 14/211,132 (publicado sob o número US 20140272352) descreve a adição de nanopartícuias inorgânicas, com destaque para a argila, a resinas poliolefínicas para promover a adesão de camadas de substratos celulósicos formando compósitos repolpáveis. A patente US 6,242,593 descreve a fabricação de adesivos biodegradáveis e repolpáveis a partir de copolímeros de monômeros vinílicos e ésteres de ácidos maleicos de alquilpoliglicosídeos . No entanto, a metodologia de produção dos adesivos que é proposta nesta invenção difere das reveladas nestes documentos dado que tem como matéria-prima somente a celulose, não compreendendo polímeros de outras naturezas, celuloses modificadas ou derivados de celulose. [0012] Reports from authors skilled in sizing cellulosic derivatives indicate that the wet cellulose sizing process offers many difficulties for successful execution. Robert Pelton, an international authority on the art, in this regard states in Microgel adhesive for wet cellulose: measurements and modeling (article published in Langmuir in 2012) that "wet cellulose is a challenging substrate". For wet cellulose bonding, highly complex and specifically developed adhesives such as polyvinylamines in poly-N-isopropylacrylamide microgels are generally required. Other polymer systems for this purpose may be less complex, but their sizing processes comprise steps that result in operational disadvantages. One such case is described in US patent 7,294,670, where an aqueous dispersion of polyurethane resin is used for adhesion on wet and dry paper lamination, but this bonding requires a necessary curing step. However, adhesives which are products of the invention described herein are of low complexity both in composition and production process, and unlike the adhesives reported above, they have the ability to glue wet cellulosic substrates with optimum efficiency. Prior art documents have been found that disclose adhesive manufacturing processes that deal with repulping of cellulosic substrates. US 14 / 083,286 (published under US 20140120277) describes repulpable adhesives based on acrylic monomers or polymers and modified PET. US 14 / 211,132 (published under US 20140272352) describes the addition of inorganic nanoparticles, especially clay, to polyolefin resins to promote the adhesion of layers of cellulosic substrates forming repulpable composites. US 6,242,593 describes the manufacture of biodegradable and repulpable adhesives from vinyl monomer copolymers and alkyl polyglycoside maleic acid esters. However, the adhesive production methodology proposed in this invention differs from those disclosed in these documents in that it has only cellulose as its raw material, not comprising other polymers, modified celluloses or cellulose derivatives.
[0014] Não foi identificado nenhum documento no estado da técnica que descrevesse o uso da celulose como matéria prima para elaboração de adesivos totalmente repolpáveis para substratos celulósicos de diferentes naturezas. A invenção aqui proposta traz como novidade em relação ao estado da técnica o uso da celulose como material de partida considerando duas possíveis alternativas: (i) uma celulose livre de substâncias que reduzem a eficiência do processo de solubilização e plastificação e limitam a repolpabilidade, ou (ii) uma polpa de celulose proveniente de uma fonte biomássica previamente tratada para maximizar a quantidade de celulose e eliminar ou reduzir ao máximo a presença de substâncias que reduzem a eficiência do processo de solubilização e plastificação. As substâncias indesejáveis compreendem compostos de diferentes naturezas, sendo os mais comuns a lignina e a hemicelulose . No prior art document describing the use of cellulose as a raw material for the production of fully repulpable adhesives for different types of cellulosic substrates has been identified. The invention here proposed as novel in relation to the state of the art is the use of cellulose as a starting material considering two possible alternatives: (i) a substance-free cellulose that reduces the efficiency of the solubilization and plasticization process and limits repulpability, or (ii) a cellulose pulp from a previously treated biomass source to maximize the amount of cellulose and eliminate or minimize the presence of substances that reduce the efficiency of the solubilization and plasticization process. Undesirable substances include compounds of different natures, the most common being lignin and hemicellulose.
[0015] Os fenómenos de adesão associados com a fabricação e uso final de produtos de papel são estudados há longo tempo. Boxin e Hyock, autores que amplamente estudaram o tema, revelam em Adhesion of Polymers in Paper Products from the Macroscopic to Molecular Levei — an overview (artigo publicado no Journal of Adhesion Science and Technology, 25 (2011) pp . 557-579), que a aplicação de polímeros sobre a superfície de papéis tem sido uma prática comum para melhorar e agregar valor aos produtos de papel. Contudo, poucas pesquisas se concentraram em compreender o mecanismo da adesão entre estes polímeros e os papéis, em contraste com o enorme volume de informação disponível sobre: (i) o fenómeno de adesão, individualmente dito, (ii) adesivos, propriamente ditos, e (ii) a tecnologia de produção de papel, sendo que a maioria desta informação é decorrente de estudos realizados dentro de uma perspectiva de fenómenos físicos e mecânicos. Segundo os autores, a adesão em papel pode se tornar mais eficiente desde que possam ser desenvolvidos sistemas com bases poliméricas e aditivos especialmente selecionados para atender as características intrínsecas dos substratos celulósicos.  The adhesion phenomena associated with the manufacture and end use of paper products have been studied for a long time. Boxin and Hyock, authors who have extensively studied the subject, reveal in Adhesion of Polymers in Paper Products from the Macroscopic to Light Molecular - an overview (article published in the Journal of Adhesion Science and Technology, 25 (2011) pp. 557-579), The application of polymers to the paper surface has been a common practice to improve and add value to paper products. However, little research has focused on understanding the adhesion mechanism between these polymers and papers, in contrast to the huge amount of information available on: (i) the adhesion phenomenon, individually stated, (ii) adhesives themselves, and (ii) the technology of paper production, most of this information comes from studies conducted from the perspective of physical and mechanical phenomena. According to the authors, paper adhesion can become more efficient provided that systems with polymeric bases and specially selected additives can be developed to meet the intrinsic characteristics of cellulosic substrates.
[0016] A escolha do aditivo para soluções adesivas em base aquosa é limitada por questões ligadas à sua compatibilidade com o adesivo e à aplicação final do material colado. Por exemplo, no caso da colagem de papel para cigarros, em geral é usada uma solução aquosa de adesivo à base de carboximetilcelulose livre de qualquer aditivo que possivelmente apresente um potencial de toxicidade ao fumante. Além disso, o aditivo a ser escolhido ainda precisa ser totalmente solúvel em água, ser compatível com a base celulósica e não desestabilizar a solução formada. Aditivos ainda podem trazer um custo adicional à preparação das soluções . The choice of the additive for aqueous based adhesive solutions is limited because of its compatibility with the adhesive and the final application of the bonded material. For example, in the case of cigarette paper bonding, an aqueous solution of carboxymethylcellulose free of any additives that may have a potential for toxicity to the smoker. In addition, the additive to be chosen must still be fully water soluble, compatible with the cellulosic base and not destabilize the solution formed. Additives may still come at an additional cost to prepare solutions.
[0017] Em geral, soluções compostas por um específico polímero têm bom desempenho como adesivos para unir peças e partes constituídas pelo mesmo polímero. Baseado nesta afirmação e visando atender as questões de custo e sustentabilidade citadas nesta invenção, o adesivo ideal para um papel 100% repolpável será uma solução aquosa de celulose. Infelizmente, a celulose é notoriamente insolúvel em água e na grande maioria dos líquidos conhecidos e de baixo impacto ambiental, o que torna a obtenção desta referida solução um desafio. Adicionalmente, a solução precisará estar isenta de impurezas ou aditivos que interfiram negativamente no reprocessamento dos substratos e repolpagem.  In general, solutions composed of a specific polymer perform well as adhesives for joining parts and parts made of the same polymer. Based on this statement and in order to address the cost and sustainability issues cited in this invention, the ideal adhesive for 100% repulpable paper will be an aqueous cellulose solution. Unfortunately, cellulose is notoriously insoluble in water and in the vast majority of known low environmental impact liquids, which makes obtaining this solution a challenge. Additionally, the solution will need to be free of impurities or additives that negatively interfere with substrate reprocessing and repulping.
[0018] Os fatores da insolubilidade da celulose são atualmente o centro de uma controvérsia científica. A literatura descreve a obtenção de soluções aquosas de celulose, mas os resultados dos experimentos de solubilização não foram totalmente compreendidos. A eficiência do processo de produção das soluções e a eficácia das soluções produzidas, em diferentes aplicações finais, têm sido debatidas nas últimas décadas. Adicionalmente, os melhores solventes para a celulose apresentam ressalvas de uso, pois: (i) são exóticos, como soluções de cupramônio, (ii) ambientalmente indesejáveis, como xantogenato, ou (iii) excessivamente caros, como soluções de morfolina e alguns líquidos iónicos. [0018] Factors of cellulose insolubility are currently the center of a scientific controversy. The literature describes obtaining aqueous cellulose solutions, but the results of the solubilization experiments were not fully understood. The efficiency of the solution production process and the effectiveness of the solutions produced in different end applications have been debated in recent decades. In addition, the best cellulose solvents have caveats of use because: (i) they are exotic, such as cuprammonium solutions, (ii) environmentally undesirable, such as xantogenate, or (iii) excessively expensive, such as morpholine solutions and some ionic liquids.
[0019] Dificuldades do uso direto da celulose como adesivo, devido à sua insolubilidade em solventes comuns, foram reveladas por Baumann e Conner no Capítulo 22 do Handbook of adhesive technology, revised and expanded. Algumas soluções para este problema são conseguidas através de modificações químicas na celulose, que geram derivados celulósicos processáveis em diferentes solventes.  [0019] Difficulties in the direct use of cellulose as an adhesive due to its insolubility in common solvents were revealed by Baumann and Conner in Chapter 22 of the Handbook of adhesive technology, revised and expanded. Some solutions to this problem are achieved through chemical modifications in cellulose, which generate processable cellulosic derivatives in different solvents.
[0020] No estado da técnica, estão disponíveis várias patentes e pedidos de patentes que descrevem a produção de adesivos e de outros tipos de revestimentos para papel a partir de soluções aquosas de celulose modificada ou de seus derivados. Os documentos EP 2432828, DE 19725448, DE 10249838, GB 366586, GB 552442, GB 9100277, JP 09040926, JP 5240520, US 5,536,778, US 5,416,140, US 5,087,649, US 4,731,162, US 4,464,202, WO1991013121 e KR 20140086023 revelam a produção de soluções aquosas repolpáveis a partir de derivados da celulose, porém, diferentemente do proposto nesta invenção, nenhuma delas partiu diretamente da celulose. Estes documentos apresentam, como material de partida para a produção das soluções, polímeros solúveis derivados da celulose que hoje são amplamente usados pela indústria, tais como: (i) a hidroxietilcelulose, de uso geral, (ii) o acetato-butirato de celulose, usado principalmente para a colagem entre papéis de diferentes composições e de papéis em plásticos, (iii) a metilcelulose, aplicada em substratos celulósicos quando se deseja minimizar o efeito de enrugamento e, (iv) a etilcelulose, apropriada para colagem de substratos celulósicos a baixas temperaturas. Os polímeros solúveis de celulose acima citados se concentram nos efluentes aquosos gerados pelo processo de reciclagem, contribuindo para o aumento de demanda bioquímica de oxigénio dos efluentes e interferindo nos processos de floculação utilizados para o seu tratamento. In the prior art, various patents and patent applications are available describing the production of adhesives and other types of paper coatings from aqueous modified cellulose solutions or derivatives thereof. EP 2432828, DE 19725448, DE 10249838, GB 366586, GB 552442, GB 9100277, JP 09040926, JP 5240520, US 5,536,778, US 5,416,140, US 4,787,162, US 4,464,202, WO1991013121 and KR 20140086023 production solutions. Aqueous repulpable from cellulose derivatives, however, unlike that proposed in this invention, none of them came directly from cellulose. These documents provide, as a starting material for the production of solutions, soluble cellulose-derived polymers that are widely used in industry today, such as: (i) hydroxyethylcellulose, commonly used, (ii) cellulose acetate butyrate, mainly used for bonding between papers of different compositions and papers in plastics, (iii) methylcellulose, applied on cellulosic substrates when the wrinkling effect is to be minimized and (iv) ethylcellulose, suitable for bonding cellulosic substrates at low temperatures. The aforementioned soluble cellulose polymers concentrate on the aqueous effluents generated by the recycling process, contributing to the increased biochemical oxygen demand of the effluents and interfering with the flocculation processes used for their treatment.
[0021] A maioria dos adesivos derivados da celulose e de outros carboidratos é usada nas indústrias de papel e têxtil como ligantes e aditivos funcionais. Nesta classe de adesivos, a adesão é promovida por evaporação ou difusão de solvente, aquoso ou não.  Most adhesives derived from cellulose and other carbohydrates are used in the paper and textile industries as binders and functional additives. In this class of adhesives, adhesion is promoted by evaporation or diffusion of solvent, aqueous or not.
[0022] Contudo, a obtenção de adesivos em solução aquosa diretamente a partir da celulose que: (i) sejam estáveis química e termicamente, (ii) sequem dentro do intervalo de tempo mais curto sem causar efeitos colaterais à superfície do substrato, como enrugamento, e (iii) que apresentem um balanço favorável na relação entre custo e desempenho ainda é um desafio para os versados no estado da arte, devido à necessidade de se desenvolver processos de tratamento da celulose que otimizem a sua solubilização nos solventes de interesse, especialmente em se considerando a variabilidade da composição da biomassa em função da sua natureza e origem.  However, obtaining adhesives in aqueous solution directly from cellulose that: (i) are chemically and thermally stable, (ii) dry within the shortest time without causing side effects to the substrate surface, such as wrinkling , and (iii) presenting a favorable balance in cost-performance ratio is still a challenge for those skilled in the art, due to the need to develop cellulose treatment processes that optimize its solubilization in the solvents of interest, especially considering the variability of biomass composition as a function of its nature and origin.
[0023] Esta invenção revela um processo composto por um conjunto de etapas que permitem a solubilização ou plastificação de celulose ou de polpas de fontes biomássicas maj oritariamente constituídas por celulose. A etapa principal do processo compreende um cisalhamento mecânico do material de partida sob baixa temperatura em meio aquoso e condições alcalinas.  [0023] This invention discloses a process comprising a set of steps that allow the solubilization or plasticization of cellulose or pulps from predominantly cellulose-based biomassic sources. The main step of the process comprises mechanical shearing of the starting material under low temperature in aqueous medium and alkaline conditions.
[0024] Embora o intumescimento de celulose em soluções alcalinas tenha sido descrito por John Mercer em 1844, com a mercerizaçao de fibras de algodão em presença de hidróxido de sódio, e tenha sido amplamente discutido na literatura aberta, a preparação de soluções de celulose em baixas temperaturas em solventes alcalinos somente foi descrita em 1987 por Kamide e Okajima na patente US 4,634,470. Não foi encontrada nenhuma anterioridade, nas bases de dados, para seu uso no preparo de adesivos à base de celulose, assim como nenhuma anterioridade para sua aplicação em um processo de produção tal como o aqui apresentado. Although cellulose swelling in solutions Alkaline was described by John Mercer in 1844, with the mercerization of cotton fibers in the presence of sodium hydroxide, and has been widely discussed in the open literature, the preparation of low temperature cellulose solutions in alkaline solvents was only described in 1987. by Kamide and Okajima in US Patent 4,634,470. No priorities were found in the databases for their use in preparing cellulose-based adhesives, as well as no priorities for their application in a production process such as the one presented herein.
[0025] Os resultados obtidos através do processo aqui descrito indicam que, contrariamente aos reportes efetuados por diferentes autores em registros históricos no estado da arte, celulose e polpas de fontes biomássicas lignocelulósicas propriamente tratadas podem ser utilizadas diretamente como material de partida para produção de adesivos que apresentam excelente desempenho na colagem de papel seco ou úmido, formando juntas mais resistentes a esforços mecânicos que as próprias folhas de papel coladas em presença de outros adesivos.  The results obtained through the process described herein indicate that, contrary to reports made by different authors in state-of-the-art historical records, pulp and pulp from properly treated lignocellulosic biome sources can be used directly as a starting material for the production of adhesives. They perform well in bonding dry or wet paper, forming joints that are more resistant to mechanical stress than the actual sheets bonded in the presence of other adhesives.
[0026] Uma vantagem significativa desta invenção é que papéis e outros substratos celulósicos nos quais foram aplicados os adesivos da presente invenção foram passíveis de reprocessamento e repolpagem em sua totalidade, resolvendo um problema tecnológico bem conhecido do estado da arte. Desta forma, os adesivos apresentados nesta invenção possuem um significativo potencial para imediata aplicabilidade pelas indústrias de produção e de transformação de papel e de outras fontes biomássicas maj oritariamente compostas por celulose e para substituição total ou parcial de adesivos usados por estes setores. A significant advantage of this invention is that papers and other cellulosic substrates on which the adhesives of the present invention were applied were subject to reprocessing and repulping in their entirety, solving a state-of-the-art technological problem. Thus, the adhesives presented in this invention have significant potential for immediate applicability by the papermaking and papermaking industries and other biomechanical sources mainly composed of cellulose and for substitution total or partial adhesives used by these sectors.
BREVE DESCRIÇÃO DA INVENÇÃO BRIEF DESCRIPTION OF THE INVENTION
[0027] Esta invenção se refere a adesivos repolpáveis produzidos pela solubilização ou plastificação de celulose ou de polpas de outras fontes biomássicas lignocelulósicas maj oritariamente constituídas por celulose, através de um conjunto de etapas de processo cuja etapa principal é o cisalhamento do material de partida em meio aquoso alcalino sob baixa temperatura. Os adesivos resultantes podem ser aplicados sobre a superfície de papéis e outros substratos celulósicos com diferentes teores de umidade, desde totalmente seco até totalmente úmido.  This invention relates to repulpable adhesives produced by solubilizing or plasticizing cellulose or pulps from other lignocellulosic biomedical sources predominantly composed of cellulose, through a set of process steps whose main step is the shear of the starting material in alkaline aqueous medium under low temperature. The resulting adhesives can be applied to the surface of paper and other cellulosic substrates with different moisture contents, from totally dry to fully wet.
[0028] Ainda, os adesivos da presente invenção proporcionam uma boa eficiência de colagem somente com a presença de celulose em sua composição, sem a necessidade de aditivar a formulação com éteres, ésteres ou outros derivados de celulose, ou outras bases poliméricas sintéticas tais como polivinilálcool , vinílicos, acrilatos, vinil-acrílicos , estireno-acrílicos , cianoacrilatos , aminoacrilatos , resinas estireno-butadieno e resinas isopreno-acríliças , entre outros polímeros conhecidos e utilizados no estado da arte como componentes de adesivos em base aquosa.  Furthermore, the adhesives of the present invention provide good sizing efficiency only with the presence of cellulose in its composition, without the need to add the formulation with ethers, esters or other cellulose derivatives, or other synthetic polymer bases such as polyvinyl alcohol, vinyls, acrylates, vinyl acrylics, styrene acrylics, cyanoacrylates, aminoacrylates, styrene butadiene resins and isoprene acrylic resins, among other known polymers used in the art as water based adhesive components.
[0029] Os materiais de partida da presente invenção são celuloses de diferentes graus de pureza, cristalinidade e razão de aspecto, que podem ser eficientemente solubilizadas ou plastificadas através do conjunto de etapas de processo descrito neste documento e resultam em adesivos que poderão ser aplicados sobre os substratos celulósicos na forma de soluções, pastas ou outras formas físicas.  The starting materials of the present invention are celluloses of varying degrees of purity, crystallinity and aspect ratio which can be efficiently solubilized or plasticized by the process steps described herein and result in adhesives which may be applied over cellulosic substrates in the form of solutions, pastes or other physical forms.
[0030] O desempenho dos adesivos à base de celulose propostos nesta invenção ainda pode ser significativamente melhorado pela incorporação ao meio, durante o processo de produção da solução adesiva, de aditivos tais como: óxidos metálicos, álcoois e gliceróis, tensoativos catiônicos, aniônicos e não-iônicos, sabões de metais alcalinos, argilas e nanoparticulas diversas que podem exercer função de plastificantes ou de agentes de reforço para melhorar a adesão do aditivo ao substrato, entre outras possibilidades de compostos. [0030] The performance of cellulose based adhesives proposed in this invention can still be significantly improved by incorporating into the medium during the adhesive production process additives such as: metal oxides, alcohols and glycerols, cationic, anionic and nonionic surfactants, alkali metal soaps, clays and miscellaneous nanoparticles which may function as plasticizers or reinforcing agents to improve adhesion of the additive to the substrate, among other compound possibilities.
[0031] As juntas adesivas obtidas a partir dos adesivos produzidos nesta invenção são 100% repolpáveis. A polpa produzida após o reprocessamento destas juntas, ou dos substratos que contêm estas juntas, não é distinguivel de uma polpa obtida com o mesmo papel na ausência de adesivo.  The adhesive joints obtained from the adhesives produced in this invention are 100% repulpable. Pulp produced after reprocessing these joints, or the substrates containing these joints, is not distinguishable from a pulp obtained with the same paper in the absence of adhesive.
[0032] O excelente desempenho dos adesivos produzidos nesta invenção foi comprovado pela execução de ensaios de resistência mecânica sob condições controladas de juntas adesivas produzidas pela colagem de diferentes substratos por diferentes formulações de soluções adesivas produzidas através do conjunto de etapas de processo desta invenção. Todas as juntas adesivas coladas pelas soluções resistiram às condições dos ensaios. Rasgos e falhas ocorreram nas regiões situadas fora das juntas adesivas.  The excellent performance of the adhesives produced in this invention has been proven by performing mechanical strength tests under controlled conditions of adhesive joints produced by bonding different substrates by different adhesive solution formulations produced by the process stepset of this invention. All adhesive joints glued by the solutions withstood the test conditions. Tearing and failures occurred in regions outside the adhesive joints.
BREVE DESCRIÇÃO DAS FIGURAS BRIEF DESCRIPTION OF THE FIGURES
[0033] A Figura 1 é uma imagem fotográfica que mostra o comportamento das juntas adesivas de 12 corpos de prova submetidos a ensaio de resistência mecânica sob condições controladas. Os corpos de prova foram produzidos a partir da colagem de 24 tiras de papel de filtro, duas a duas, com uma solução aquosa de adesivo produzida através da presente invenção . [0033] Figure 1 is a photographic image showing the behavior of the adhesive joints of 12 specimens subjected to mechanical strength testing under controlled conditions. The specimens were produced by gluing 24 strips of filter paper two by two with an aqueous adhesive solution produced by the present invention.
[0034] A Figura 2 é uma representação esquemática da reconstrução de um papel de filtro colado com uma solução adesiva produzida através da presente invenção, obtida por microtomografia de raios-X.  Figure 2 is a schematic representation of the reconstruction of a filter paper bonded with an adhesive solution produced by the present invention obtained by X-ray microtomography.
[0035] As Figuras 3A e 3B são imagens fotográficas que revelam a decantação da polpa de amostras de tiras de um mesmo papel de filtro que foram unidas por colagem e posteriormente trituradas com água. A figura 3A mostra a decantação da polpa de 5 pares de tiras de papel de filtro comercial previamente coladas com um adesivo à base de acetato de polivinila, comercialmente conhecido por látex PVA. A figura 3B mostra a decantação da polpa de 5 pares de tiras do mesmo papel de filtro previamente coladas com uma solução aquosa alcalina de celulose preparada de acordo com o Exemplo 1 da presente invenção. A figura 3C mostra o resultado da trituração e repolpagem da amostra de referência, ou seja, o papel de filtro sem a adição de adesivos .  Figures 3A and 3B are photographic images showing the decantation of the pulp from strips of the same filter paper which were glued together and then triturated with water. Figure 3A shows the pulp decantation of 5 pairs of commercial filter paper strips previously bonded with a polyvinyl acetate-based adhesive, commercially known as PVA latex. Figure 3B shows the decantation of the pulp from 5 pairs of strips of the same filter paper previously pasted with an alkaline aqueous cellulose solution prepared according to Example 1 of the present invention. Figure 3C shows the result of grinding and repulping the reference sample, ie the filter paper without the addition of adhesives.
[0036] As Figuras 4A, 4B e 4C são imagens fotográficas que revelam modos de aplicação do adesivo produzido na presente invenção na forma de solução sobre um substrato de papel de filtro comercial. A figura 4A mostra a aplicação da solução adesiva sobre a extremidade de uma tira de papel de modo a delimitar a região da junta adesiva. A figura 4B mostra a união de duas tiras pelas suas extremidades, formando o corpo de prova. A figura 4C mostra o corpo de prova unido pela junta adesiva após aplicação de força compressiva, pronto para ser submetido à secagem.  Figures 4A, 4B and 4C are photographic images showing modes of application of the adhesive produced in the present invention as a solution on a commercial filter paper substrate. Figure 4A shows the application of the adhesive solution to the end of a paper strip to delimit the region of the adhesive joint. Figure 4B shows the union of two strips at their ends, forming the specimen. Figure 4C shows the specimen joined by the adhesive joint after applying compressive force, ready to be dried.
DESCRIÇÃO DETALHADA DAS FIGURAS [0037] A Figura 3 é uma imagem fotográfica de 24 tiras de papel de filtro de mesma dimensão coladas duas a duas com uma solução aquosa de adesivo composta por 5% em massa de celulose e 7% em massa de NaOH que foi preparada por tratamento térmico e mecânico. Os 12 corpos de prova colados foram condicionados a 23 ± 2°C e 50 ± 5% de umidade por 48 h e submetidos a ensaio de tração com velocidade de 1,25 mm/min e comprimento de trabalho do corpo de prova de 140 mm. Em cada corpo de prova foi obtida tensão máxima idêntica à de uma única tira de papel (12 mPa) . A Figura 1 mostra que em todos os corpos de prova o rompimento do substrato sob tração controlada ocorreu em uma região distinta da junta adesiva, evidenciando que a junta colada pela solução adesiva é mais resistente que o próprio papel. DETAILED DESCRIPTION OF THE FIGURES Figure 3 is a photographic image of 24 strips of same size filter paper bonded two by two with an aqueous adhesive solution composed of 5 wt% cellulose and 7 wt% NaOH which was prepared by treatment. thermal and mechanical. The 12 bonded specimens were conditioned at 23 ± 2 ° C and 50 ± 5% humidity for 48 h and submitted to a tensile test with a speed of 1.25 mm / min and a working length of 140 mm. In each specimen, a maximum tension identical to that of a single paper strip (12 mPa) was obtained. Figure 1 shows that in all specimens the rupture of the substrate under controlled traction occurred in a distinct region of the adhesive joint, showing that the joint glued by the adhesive solution is stronger than the paper itself.
[0038] A Figura 4 é uma representação esquemática da microtomografia de raios-X da reconstrução de um papel de filtro colado com uma solução adesiva produzida conforme preparação descrita no Exemplo 1 desta invenção. Os pontos azuis da imagem indicam regiões de maior atenuação dos raios- X, ou seja, de maior densidade eletrônica. Este efeito ocorre principalmente pela presença de ions de sódio no adesivo. A Figura 2 mostra que a solução adesiva aplicada sobre o substrato preenche os espaços entre as fibras do papel, ao invés de preferencialmente se espalhar sobre a superfície das folhas e formar um filme de adesivo entre elas.  Figure 4 is a schematic representation of the X-ray microtomography of the reconstruction of a filter paper bonded with an adhesive solution produced according to the preparation described in Example 1 of this invention. The blue dots in the image indicate regions of higher X-ray attenuation, that is, of higher electron density. This effect occurs mainly by the presence of sodium ions in the adhesive. Figure 2 shows that the adhesive solution applied to the substrate fills the gaps between the paper fibers, rather than preferably spreading over the surface of the sheets and forming an adhesive film therebetween.
[0039] As Figuras 3A e 3B são imagens fotográficas que mostram polpas obtidas após repolpagem da região da junta adesiva de corpos de prova constituídos por tiras de um mesmo papel de filtro que foram unidas por colagem. A Figura 3A mostra uma polpa obtida pela trituração de 5 corpos de prova compostos por duas tiras de papel de filtro comercial previamente coladas com um adesivo à base de acetato de polivinila, comercialmente conhecido por látex PVA. 0 pH final desta dispersão foi igual a 5. A Figura 3B mostra uma polpa obtida pela trituração de 5 corpos de prova do mesmo papel de filtro comercial compostos por duas tiras coladas com uma solução aquosa alcalina de celulose preparada de acordo com o Exemplo 1 desta invenção. 0 pH final desta dispersão foi 6. A Figura 3C mostra o resultado da trituração e repolpagem da amostra de referência, ou seja, o mesmo papel de filtro comercial sem a adição de adesivos. A área triturada era de mesma dimensão que as áreas das juntas adesivas dos corpos de prova das Figuras 3A e 3B. Esta dispersão apresentou pH 5. 0 processo de repolpagem para as preparações 3A, 3B e 3C foi semelhante e compreendeu a trituração das juntas em liquidificador na presença de 100 ml de água e decantação da polpa sob repouso por 30 minutos. A Figura 3B mostra que a dispersão contendo a polpa da junta adesiva do corpo de prova colado pela solução adesiva produzida na presente invenção decanta totalmente, assim como a dispersão da amostra de referência (Figura 3C) . Já a dispersão contendo a polpa da junta adesiva do corpo de prova colado com o adesivo comercial de látex PVA (Figura 3A) não decanta, ocorrendo presença de sobrenadante e indicando que este adesivo comercial não é 100% repolpável, limitando um eficiente reprocessamento industrial. Figures 3A and 3B are photographic images showing pulps obtained after repulping the region of the adhesive joint of strips of the same filter paper which have been bonded together. Figure 3A shows a pulp obtained by grinding 5 specimens. composed of two strips of commercial filter paper previously bonded with a polyvinyl acetate-based adhesive, commercially known as PVA latex. The final pH of this dispersion was 5. Figure 3B shows a pulp obtained by grinding 5 specimens of the same commercial filter paper composed of two strips bonded with an alkaline aqueous cellulose solution prepared according to Example 1 of this invention. The final pH of this dispersion was 6. Figure 3C shows the result of grinding and repulping the reference sample, ie the same commercial filter paper without the addition of adhesives. The crushed area was the same size as the adhesive joint areas of the test specimens of Figures 3A and 3B. This dispersion was pH 5. The repulping process for preparations 3A, 3B and 3C was similar and comprised grinding the joints in a blender in the presence of 100 ml of water and decanting the pulp under rest for 30 minutes. Figure 3B shows that the dispersion containing the specimen adhesive joint pulp glued by the adhesive solution produced in the present invention is completely decanted, as well as the dispersion of the reference sample (Figure 3C). The dispersion containing the specimen adhesive joint pulp bonded with the PVA latex commercial adhesive (Figure 3A) does not decant, with the presence of supernatant and indicating that this commercial adhesive is not 100% repulpable, limiting efficient industrial reprocessing.
[0040] A Figura 4A é uma imagem fotográfica que mostra uma solução adesiva composta por 5% em massa de papel de filtro qualitativo comercial e 7% em massa de NaOH e preparada segundo as etapas descritas nesta invenção, sendo manualmente aplicada por meio de uma laminula de vidro sobre a extremidade de uma tira de papel de filtro qualitativo comercial de dimensão 10,0 cm x 2,5 cm x 0,12 cm. A extremidade da tira seca com área de 1 cm x 2,5 cm foi coberta por 40 mg da solução adesiva. A Figura 4B mostra o corpo de prova após a união das extremidades de duas tiras preparadas segundo o procedimento descrito na Figura 4A. A Figura 4C apresenta o corpo de prova após a aplicação de força compressiva de aproximadamente 700 N por 5 s sobre a região colada, formando a junta adesiva. Figure 4A is a photographic image showing an adhesive solution composed of 5 mass% commercial qualitative filter paper and 7 mass% NaOH prepared according to the steps described in this invention. manually applied by means of a glass laminate over the end of a commercial qualitative filter paper strip 10.0 cm x 2.5 cm x 0.12 cm. The end of the 1 cm x 2.5 cm dry strip was covered with 40 mg of the adhesive solution. Figure 4B shows the specimen after joining the ends of two strips prepared according to the procedure described in Figure 4A. Figure 4C shows the specimen after the application of compressive force of approximately 700 N for 5 s over the bonded region forming the adhesive joint.
DESCRIÇÃO DETALHADA DA INVENÇÃO DETAILED DESCRIPTION OF THE INVENTION
[0041] Os adesivos repolpáveis apresentados nesta invenção resolvem problemas usuais e indesejáveis na fabricação de derivados celulósicos, especialmente na produção de papel, facilitando a total reciclagem e repolpagem dos substratos celulósicos após o uso.  The repulpable adhesives presented in this invention solve usual and undesirable problems in the manufacture of cellulosic derivatives, especially in the production of paper, facilitating the complete recycling and repulping of cellulosic substrates after use.
[0042] Adesivos normalmente utilizados na fabricação de artefatos de papel e papelão têm excelentes propriedades mecânicas, mas criam um problema quando são novamente transformados em polpa celulósica, pois formam uma borra insolúvel em água que contamina a polpa. Este problema operacional é conhecido no estado da técnica e citado por vários autores, como Venditti, Lucas e Jameel. Os depósitos de adesivos provocam a obstrução de malhas utilizadas no processo, acarretando a redução da velocidade de produção, além de defeitos no papel e problemas de impressão.  Adhesives commonly used in the manufacture of paper and cardboard artifacts have excellent mechanical properties, but create a problem when they are once again made into cellulosic pulp as they form a water-insoluble sludge that contaminates the pulp. This operational problem is known in the state of the art and cited by several authors, such as Venditti, Lucas and Jameel. Adhesive deposits clog the mesh used in the process, leading to reduced production speed, paper defects and printing problems.
[0043] Esse problema é resolvido pela presente invenção, que revela adesivos produzidos por solubili zação ou plastificação de celulose ou de polpa de celulose obtida pelo tratamento de diferentes fontes biomássicas, usando um conjunto de etapas produtivas sob condições controladas que incluem a mistura mecânica do sólido celulósico e do liquido alcalino e o resfriamento desta mistura para aumentar a solubilidade da celulose ou o seu grau de intumescimento . This problem is solved by the present invention, which discloses adhesives produced by solubilization or plasticization of cellulose or cellulose pulp obtained by treating different biomassic sources using a set of production steps under controlled conditions that include the mechanical mixing of the cellulosic solid and the alkaline liquid and cooling of this mixture to increase the solubility of the cellulose or its swelling.
[0044] Os adesivos repolpáveis da presente invenção compreendem de 0,5% a 35% em massa de celulose (CAS Number 9004-34-6) ou polpa majoritariamente composta por celulose (CAS Number 65996-61-4), total ou parcialmente solubilizada em um meio solvente, e de 1% a 10% em massa de um ou mais álcalis, total ou parcialmente solubilizados no meio solvente. Os referidos um ou mais álcalis são selecionados a partir de um grupo que compreende hidróxidos de sódio, potássio, lítio, cálcio e amónio, tetrametilamônio, ou aluminatos e zincatos de metais alcalinos.  The repulpable adhesives of the present invention comprise from 0.5% to 35% by weight of cellulose (CAS Number 9004-34-6) or pulp mainly composed of cellulose (CAS Number 65996-61-4), wholly or partially. solubilized in a solvent medium, and from 1% to 10% by weight of one or more alkalis, totally or partially solubilized in the solvent medium. Said one or more alkalis are selected from a group comprising sodium, potassium, lithium, calcium and ammonium hydroxides, tetramethylammonium, or alkali metal aluminates and zincates.
[0045] Os adesivos repolpáveis da presente invenção compreendem, opcionalmente, um ou mais aditivos em uma concentração de 0% a 30% em massa, total ou parcialmente solubilizados no meio solvente.  The repulpable adhesives of the present invention optionally comprise one or more additives in a concentration of 0% to 30% by weight, totally or partially solubilized in the solvent medium.
[0046] O adesivo resultante na forma de solução ou pasta é aplicado nas superfícies do substrato celulósico formando juntas adesivas que serão coladas como lap joints, ou juntas de encaixe, ou como butt joints, ou juntas de topo. Como o polímero majoritariamente presente na composição no adesivo é a celulose (CA Number 9004-34-6), esta se incorpora à polpa e não prejudica a sua formação nem a contamina com impurezas indesejáveis, assim possibilitando a total repolpagem do substrato .  The resulting solution or paste adhesive is applied to the surfaces of the cellulosic substrate forming adhesive joints that will be glued as lap joints, or joint joints, or as butt joints, or butt joints. As the polymer predominantly present in the composition in the adhesive is cellulose (CA Number 9004-34-6), it is incorporated into the pulp and does not impair its formation or contaminate it with undesirable impurities, thus enabling full repulping of the substrate.
[0047] Em uma modalidade alternativa da invenção, o adesivo é produzido pela mistura de uma solução ou dispersão alcalina de celulose com um aditivo sólido neutralizante, tal como o bicarbonato de sódio, o bórax, o ácido bórico ou qualquer outra substância com ação tamponante em pH neutro, para evitar o manuseio de uma solução fortemente alcalina durante a colagem do papel. In an alternative embodiment of the invention, the adhesive is produced by mixing an alkaline cellulose solution or dispersion with a neutralizing solid additive. such as sodium bicarbonate, borax, boric acid or any other buffering substance at neutral pH, to avoid handling a strongly alkaline solution while bonding the paper.
[0048] Em outra modalidade da invenção, o adesivo é produzido pela adição à solução alcalina de celulose de um aditivo hidrotrópico como a uréia, tiouréia, mono-, di- e trietanolaminas , glicerol, etanol e outros álcoois, dimetilsulfóxido, toluenossulfonatos , xilenossulfonatos , cumenossulfonatos , lignossulfonatos , benzoatos, salicilatos, citratos, acetatos e outros compostos conhecidos da arte.  In another embodiment of the invention, the adhesive is produced by adding to the alkaline cellulose solution a hydrotropic additive such as urea, thiourea, mono-, di- and triethanolamines, glycerol, ethanol and other alcohols, dimethyl sulfoxide, toluenesulfonates, xylenesulfonates. , cumenesulfonates, lignosulfonates, benzoates, salicylates, citrates, acetates and other compounds known in the art.
[0049] Ainda em outra modalidade da invenção, a solução ou dispersão alcalina de celulose é aditivada com óxidos de zinco, alumínio, vanádio, estanho e germânio.  In yet another embodiment of the invention, the alkaline cellulose solution or dispersion is added with zinc, aluminum, vanadium, tin and germanium oxides.
[0050] Em outra modalidade da invenção, a solução ou dispersão alcalina de celulose é aditivada com compostos alcalinos como hidróxido de lítio, potássio, amónio e tetrametilamônio e óxido de cálcio.  In another embodiment of the invention, the alkaline cellulose solution or dispersion is added with alkaline compounds such as lithium hydroxide, potassium, ammonium and tetramethylammonium and calcium oxide.
[0051] Ainda em outra modalidade da invenção, a solução ou dispersão alcalina de celulose é aditivada com um dispersante tensoativo dos tipos aniônico, catiônico ou não iônico .  In yet another embodiment of the invention, the alkaline cellulose solution or dispersion is added with an anionic, cationic or nonionic surfactant dispersant.
[0052] Em uma outra modalidade da invenção, a solução ou dispersão alcalina de celulose é aditivada com nanopartícuias de argilas, óxidos metálicos, carbonatos, fosfatos ou silicatos, que atuam como agentes de reforço na colagem de peças ou folhas espessas de papelão ou cartão, melhorando as propriedades mecânicas do próprio adesivo.  In another embodiment of the invention, the alkaline cellulose solution or dispersion is additive with clay nanoparticles, metal oxides, carbonates, phosphates or silicates, which act as reinforcing agents in the bonding of thick cardboard or paperboard parts or sheets. , improving the mechanical properties of the adhesive itself.
[0053] A secagem das juntas ocorre por simples evaporação do solvente ao ar, mas pode ser acelerada por aquecimento usando qualquer método conhecido da arte, bem como por circulação forçada de ar ou exposição a um secante. [0053] Joint drying occurs by simple evaporation It can be accelerated by heating using any method known in the art, as well as by forced air circulation or exposure to a drier.
[0054] Os adesivos da presente invenção possuem diversos usos e aplicações, tais como:  The adhesives of the present invention have various uses and applications, such as:
• para a adesão ou revestimento de substratos celulósicos selecionados de um grupo que inclui fibra de celulose, mantas e tecidos celulósicos, celofane e seus filmes, celulose regenerada e seus filmes, papel, papelão, papel cartão e embalagens constituídas por celulose e seus derivados, entre outros materiais similares;  • for the adhesion or coating of selected cellulosic substrates from a group comprising cellulose fiber, cellulose wraps and fabrics, cellophane and its films, regenerated cellulose and its films, paper, cardboard, paperboard and packaging consisting of cellulose and its derivatives, among other similar materials;
• para a colagem de substratos celulósicos contendo teores de umidade preferencialmente entre 6% e 70%, quando aplicados aos mesmos;  • for bonding cellulosic substrates containing moisture contents preferably between 6% and 70% when applied to them;
· para a formação de juntas adesivas que permitem a colagem pela face ou topo das superfícies de substratos celulósicos em formas e figuras planas, tais como folhas, lâminas, lenços, absorventes, toalhas, papel higiénico, mantas, tapetes e rolos de papel e de tecido, entre outras formas similares; ou a colagem por encaixe das superfícies de substratos celulósicos em diferentes formas geométricas tais como embalagens com perfis em L, perfis em T e perfis em U, entre outras formas similares.  · For the formation of adhesive joints that allow the face or top surface to stick to cellulosic substrates in flat shapes and figures, such as sheets, sheets, wipes, tampons, towels, toilet paper, blankets, mats and paper rolls. fabric, among other similar forms; or snap-bonding the surfaces of cellulosic substrates into different geometric shapes such as L-shaped packages, T-profiles and U-profiles, among other similar forms.
[0055] A aplicação dos adesivos ao papel ou papelão seco ou úmido é feita usando qualquer método ou dispositivo conhecido pela arte e, uma vez seca, a junta adesiva resiste a esforços mecânicos controlados de tração, torção, rasgo e despelamento com um desempenho superior às próprias folhas de papel ou papelão usadas na formação da junta.  Applying the adhesives to dry or wet paper or cardboard is done using any method or device known in the art, and once dry, the adhesive resists controlled mechanical tensile, twisting, tearing and peeling efforts with superior performance. to the very sheets of paper or cardboard used in forming the joint.
[0056] A seguir são descritos exemplos das preparações dos adesivos repolpáveis produto da presente invenção, exemplos de aplicação e exemplos do desempenho e propriedades das juntas adesivas obtidas com os adesivos produtos da presente invenção. The following are examples of the preparations of the repulpable product adhesives of the present invention, application examples and examples of the performance and properties of the adhesive joints obtained with the product adhesives of the present invention.
[0057] Os exemplos a seguir apenas representam algumas modalidades da presente invenção e não devem ser considerados, de forma alguma, como limitantes do escopo e conceito inventivo da presente invenção, uma vez que há possíveis modalidades alternativas adicionais.  The following examples only represent certain embodiments of the present invention and should not be construed in any way as limiting the scope and inventive concept of the present invention, as there are possible additional alternative embodiments.
EXEMPLOSEXAMPLES
EXEMPLO 1 - PREPARO DE UMA SOLUÇÃO ADESIVA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL DE FILTRO SECAS. EXAMPLE 1 - PREPARING AN ADHESIVE SOLUTION AND ITS APPLICATION FOR COLLATING DRIED FILTER PAPER SHEETS.
[0058] Na modalidade preferencial da invenção, o adesivo é preparado em solução pela total solubilização de 5% (m/m) de celulose microcristalina de alta pureza, comercialmente disponível, oriunda de linter de algodão, em uma solução de 7% (m/m) de NaOH em água. A celulose é lentamente adicionada à solução aquosa de NaOH e homogeneizada a 0°C e 6000 rpm por 10 minutos. A solução resultante é resfriada sob repouso a -20°C por 1 h.  In the preferred embodiment of the invention, the adhesive is prepared in solution by the total solubilization of 5% (w / w) commercially available high purity microcrystalline cellulose from cotton linter in a 7% (w / w) solution. / m) NaOH in water. The cellulose is slowly added to the aqueous NaOH solution and homogenized at 0 ° C and 6000 rpm for 10 minutes. The resulting solution is cooled on standing at -20 ° C for 1 h.
[0059] A eficiência de adesão da solução adesiva é verificada através da realização de um ensaio de colagem. O referido ensaio se inicia com a aplicação de uma camada de 40 mg da solução adesiva a 242C sobre uma área de 1 cm x 2,5 cm de uma tira de papel seco de filtro qualitativo comercial de gramatura 80 g/m2 e de dimensão 10,0 cm x 2,5 cm x 0,12 cm, recobrindo totalmente a área de aplicação. Após a aplicação do adesivo na tira, as faces desta tira e de uma tira de papel seca e sem adesivo foram unidas sob força compressiva de aproximadamente 700 N por 5 s. A secagem do corpo de prova colado, posicionado sobre um filme de polietileno (PE), foi realizada a 24°C e aproximadamente 40% de umidade por 90 min. Este procedimento foi repetido de forma a gerar mais 11 corpos de prova. A eficiência da adesão foi avaliada para os 12 corpos de prova através de ensaio mecânico de tração sob condições controladas. Os corpos de prova foram condicionados a 23 ± 2 °C e 50 ± 5% de umidade por 48 h. Foi aplicada sobre os corpos de prova uma velocidade de 1,25 mm/min e comprimento de trabalho de 140 mm, obtendo-se tensão máxima idêntica à de uma única tira de papel de filtro (12 MPa) . Neste exemplo, as juntas adesivas submetidas às condições do ensaio se mostraram resistentes à tração. O rompimento de todos os corpos de prova ocorreu sempre em outra região que não a área colada, mostrando que a junta adesiva é mais resistente que o próprio papel (Figura 1) . Regiões coladas de corpos de prova aleatoriamente selecionados foram selecionadas para análise por microtomografia de raios-X (Figura 2) para avaliar a eficiência de colagem. The adhesion efficiency of the adhesive solution is verified by performing a sizing test. Said test begins by applying a 40 mg layer of the adhesive solution at 24 2 C over an area of 1 cm x 2.5 cm of a commercial grade dry weight 80 g / m 2 filter strip and 10.0 cm x 2.5 cm x 0.12 cm, completely covering the application area. After application of the adhesive to the strip, the faces of this strip and a dry strip of paper without adhesive were joined under compressive strength of approximately 700 N for 5 s. The drying of Glued specimen, placed on a polyethylene (PE) film, was held at 24 ° C and approximately 40% humidity for 90 min. This procedure was repeated to generate 11 more specimens. The adhesion efficiency was evaluated for the 12 specimens by mechanical tensile test under controlled conditions. The specimens were conditioned at 23 ± 2 ° C and 50 ± 5% humidity for 48 h. A speed of 1.25 mm / min and a working length of 140 mm was applied to the specimens, giving the maximum tension identical to that of a single strip of filter paper (12 MPa). In this example, the adhesive joints subjected to the test conditions proved to be tensile resistant. The disruption of all specimens always occurred in a region other than the glued area, showing that the adhesive joint is stronger than the paper itself (Figure 1). Glued regions from randomly selected specimens were selected for analysis by X-ray microtomography (Figure 2) to evaluate the bonding efficiency.
[0060] O desempenho da solução adesiva na repolpagem foi avaliado a partir de um ensaio que simulou o reprocessamento dos substratos colados. Cinco corpos de prova colados foram repolpados por tritura em liquidificador com a adição de 100 ml de água. Os controles selecionados para critério de comparação de eficiência de repolpagem foram tiras do papel de filtro sem adesivo e 5 corpos de prova do mesmo papel de filtro colados com um adesivo comercial de látex PVA. As suspensões trituradas foram decantadas sob repouso por 30 minutos, obtendo-se polpas de aspecto semelhante tanto no material colado quanto no controle. A suspensão de papel colado com PVA triturado em água não decantou, em função da presença de finas partículas que se mantiveram suspensas no meio (Figura 3A) , enquanto que a suspensão do papel sem adesivo (Figura 3C) e a suspensão do papel colado com o adesivo proposto pela presente invenção (Figura 3B) decantaram, possibilitando o reprocesso dos substratos colados . The performance of the adhesive solution on repulping was evaluated from an assay that simulated reprocessing of the bonded substrates. Five bonded specimens were repulped by grinding in a blender with the addition of 100 ml of water. Controls selected for repulping efficiency comparison criteria were strips of filter paper without adhesive and 5 specimens of the same filter paper bonded with a commercial PVA latex adhesive. The crushed suspensions were decanted at rest for 30 minutes, obtaining similar looking pulps in both the bonded material and the control. The paper suspension bonded with water-crushed PVA did not decant due to the presence of fine particles that remained suspended in the medium (Figure 3A), while the paper-free suspension (Figure 3C) and the paper-bonded suspension proposed by The present invention (Figure 3B) was decanted, allowing the reprocessing of the bonded substrates.
EXEMPLO 2 - PREPARO DE UMA SOLUÇÃO ADESIVA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL DE FILTRO SECAS.  EXAMPLE 2 - PREPARING AN ADHESIVE SOLUTION AND ITS APPLICATION FOR COLLATING DRIED FILTER PAPER SHEETS.
[0061] Esta modalidade da invenção difere do Exemplo 1 pela forma de aplicação do adesivo e pela superfície coberta pelo adesivo no substrato. A solução adesiva é preparada seguindo exatamente o procedimento do Exemplo 1, porém a aplicação da solução adesiva é feita em tiras de papel de filtro qualitativo comercial de gramatura 80 g/m2 e de dimensão 10,0 cm x 2,5 cm x 0,12 cm cujas extremidades foram rasgadas. 2 mm da extremidade rasgada de cada tira foi imersa na solução adesiva e a colagem de duas tiras foi feita pela junção das suas extremidades cobertas pelo adesivo. Os parâmetros de adesão e secagem das tiras coladas e os parâmetros dos ensaios de tração foram semelhantes aos descritos no exemplo 1. Nesta modalidade, as juntas adesivas coladas pelas extremidades rasgadas se mostraram resistentes à tração nas condições de ensaio. This embodiment of the invention differs from Example 1 in the form of application of the adhesive and the surface covered by the adhesive on the substrate. The adhesive solution is prepared following exactly the procedure of Example 1, but the adhesive solution is applied to commercial grade 80 g / m 2 qualitative filter paper strips of 10.0 cm x 2.5 cm x 0 size. , 12 cm whose ends have been torn. 2 mm of the torn end of each strip was immersed in the adhesive solution and the two strips were glued together by joining its adhesive-covered ends. The adhesion and drying parameters of the bonded strips and the tensile test parameters were similar to those described in example 1. In this embodiment, the adhesive joints glued by the torn ends proved to be tensile resistant under the test conditions.
EXEMPLO 3 - PREPARO DE UMA SOLUÇÃO ADESIVA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL DE SULFITE ÚMIDAS . EXAMPLE 3 - PREPARING AN ADHESIVE SOLUTION AND ITS APPLICATION FOR COLLATING Damp SULPHITE PAPER SHEETS.
[0062] Esta modalidade da invenção difere do Exemplo 1 quanto à umidade do substrato onde ocorre a colagem. Neste exemplo a colagem ocorre em folhas úmidas de papel sulfite. A solução adesiva é preparada pela total solubilização de 2% (m/m) de celulose microcristalina em uma solução de 2,8% (m/m) de NaOH em água, e, seguindo a mesma metodologia do Exemplo 1. A colagem foi realizada aplicando-se 25 mg da solução adesiva em tiras de papel sulfite úmidas de gramatura 75 g/m2 e de dimensão 10,0 cm x 2,5 cm x 0,12 cm, cobrindo uma área de 1 cm x 2,5 cm da tira de papel. As tiras de papel continham em média 60% de umidade. Após a aplicação da solução adesiva, a junção das faces entre duas tiras foi realizada conforme descrito no Exemplo 1. A secagem dos corpos de prova foi realizada a 24°C e aproximadamente 40% de umidade por 180 min, sobre um filme de PE. Nesta modalidade, todas as juntas adesivas das amostras se mostraram resistentes à tração quando submetidas a condições controladas de ensaios mecânicos. This embodiment of the invention differs from Example 1 in the moisture of the substrate where bonding occurs. In this example bonding occurs on damp sheets of sulfite paper. The adhesive solution is prepared by total solubilization of 2%. (w / w) microcrystalline cellulose in a solution of 2.8% (w / w) NaOH in water, and following the same methodology as Example 1. Sizing was performed by applying 25 mg of the adhesive solution to strips of 75 g / m 2 damp sulfite paper, 10.0 cm x 2.5 cm x 0.12 cm in size, covering an area of 1 cm x 2.5 cm of the paper strip. The strips of paper contained on average 60% humidity. After application of the adhesive solution, the joining of the faces between two strips was performed as described in Example 1. The drying of the specimens was performed at 24 ° C and approximately 40% humidity for 180 min on a PE film. In this mode, all adhesive joints of the samples proved to be tensile resistant when subjected to controlled mechanical testing conditions.
EXEMPLO 4 - PREPARO DE UMA PASTA ADESIVA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL DE FILTRO ÚMIDAS. EXAMPLE 4 - PREPARATION OF AN ADHESIVE FOLDER AND ITS APPLICATION FOR COLLATING Damp FILTER PAPER SHEETS.
[0063] Esta modalidade da invenção difere dos exemplos anteriores pelo adesivo ser produzido na forma de pasta e a colagem ser efetuada sobre folhas úmidas do papel de filtro qualitativo comercial usado no Exemplo 1. A pasta adesiva produzida neste exemplo é proporcionalmente mais rica em celulose do que as soluções adesivas reveladas nos Exemplos 1, 2, 3, 5, 6, 7 e 8 desta invenção. A pasta adesiva é preparada pela solubilização parcial de 20% (m/m) de celulose microcristalina em uma solução de 7% (m/m) de NaOH em água. A solução alcalina foi resfriada a 02C e a celulose foi adicionada a esta solução sob agitação lenta e baixo cisalhamento . A homogeneização se estendeu por 10 minutos e ao final a dispersão foi resfriada em repouso a -202C por lh, gerando a pasta adesiva, que apresenta aspecto opaco, diferentemente do aspecto translúcido das soluções adesivas dos demais exemplos desta invenção. A colagem foi realizada aplicando uma única camada de 25 mg da pasta adesiva a 242C sobre uma área de 1 cm x 2,5 cm das tiras úmidas de papel de filtro qualitativo de gramatura 80 g/m2 e de dimensão de 10,0 cm x 2,5 cm x 0,12 cm. As tiras de papel continham em média 60% de umidade. Após a aplicação da pasta adesiva, a junção das faces de duas tiras foi realizada seguindo o mesmo procedimento do Exemplo 1. A secagem das amostras foi realizada seguindo o procedimento do Exemplo 3. Nesta modalidade, todas as juntas adesivas das amostras se mostraram resistentes à tração quando submetidas a condições controladas de ensaios mecânicos. This embodiment of the invention differs from the previous examples in that the adhesive is produced in paste form and the sizing is performed on damp sheets of the commercial qualitative filter paper used in Example 1. The adhesive paste produced in this example is proportionally richer in cellulose. than the adhesive solutions disclosed in Examples 1, 2, 3, 5, 6, 7 and 8 of this invention. The adhesive paste is prepared by partially solubilizing 20% (w / w) microcrystalline cellulose in a 7% (w / w) solution of NaOH in water. The alkaline solution was cooled to 0 C and 2 the pulp was added to this solution slowly and under low shear stirring. The homogenization extended for 10 minutes and at the end the dispersion was cooled at rest at -20 2 C for 1h, generating the opaque adhesive paste. unlike the translucent aspect of the adhesive solutions of the other examples of this invention. Bonding was performed by applying a single 25 mg layer of the adhesive paste at 24 2 C over an area of 1 cm x 2.5 cm of the wet strips of 80 g / m 2 qualitative weight filter paper of 10, 0 cm x 2.5 cm x 0.12 cm. The strips of paper contained on average 60% humidity. After application of the adhesive paste, the joining of the faces of two strips was performed following the same procedure as Example 1. The drying of the samples was performed following the procedure of Example 3. In this embodiment, all the adhesive joints of the samples proved to be resistant to traction when subjected to controlled mechanical test conditions.
EXEMPLO 5 - PREPARO DE UMA SOLUÇÃO ADESIVA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL SULFITE SECAS.  EXAMPLE 5 - PREPARATION OF AN ADHESIVE SOLUTION AND ITS APPLICATION FOR COLLATING DRIED SULPHITE PAPER SHEETS.
[0064] Nesta modalidade da invenção, o Exemplo 1 é repetido, porém trocando-se o papel de filtro qualitativo comercial por folhas de papel sulfite seco. Nesta modalidade, todas as juntas adesivas das amostras se mostraram resistentes à tração quando submetidas a condições controladas de ensaios mecânicos.  In this embodiment of the invention, Example 1 is repeated but the commercial qualitative filter paper is replaced with dry sulfite paper sheets. In this mode, all adhesive joints of the samples proved to be tensile resistant when subjected to controlled mechanical testing conditions.
EXEMPLO 6 - PREPARO DE UMA SOLUÇÃO ADESIVA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL FILTRO ÚMIDAS.  EXAMPLE 6 - PREPARING AN ADHESIVE SOLUTION AND ITS APPLICATION FOR COLLATING Damp FILTER PAPER SHEETS.
[0065] Esta modalidade da invenção difere dos exemplos anteriores pela solução adesiva ser preparada pela dissolução direta de 5% (m/m) de papel filtro qualitativo comercial de gramatura 87 g/m2, de concentração mínima de 98% (m/m) em celulose e sem a presença de amido, em uma solução de 7% (m/m) de NaOH em água. Os parâmetros de temperatura e agitação para solubilização são os mesmos descritos no Exemplo 1. A colagem foi realizada aplicando 25 mg da solução adesiva sobre uma área de 1 cm x 2,5 cm de tiras de papel filtro qualitativo de gramatura 80 g/m2 e de dimensão de 10,0 cm x 2,5 cm x 0,12 cm. As folhas de papel de filtro continham em média 60% de umidade. A junção das faces foi realizada seguindo o mesmo procedimento do Exemplo 1 sob força compressiva de aproximadamente 700 N por 5 s e a secagem foi realizada seguindo o mesmo procedimento do Exemplo 3. Nesta modalidade, todas as juntas adesivas das amostras se mostraram resistentes à tração quando submetidas a condições controladas de ensaios mecânicos. This embodiment of the invention differs from the previous examples in that the adhesive solution is prepared by the direct dissolution of 5% (w / w) commercial grade 87 g / m 2 filter paper with a minimum concentration of 98% (w / w). ) in cellulose and without starch, in a solution of 7% (w / w) NaOH in water. The temperature and agitation parameters for solubilization are the same. Bonding was performed by applying 25 mg of the adhesive solution over an area of 1 cm x 2.5 cm strips of qualitative filter paper weighing 80 g / m 2 and 10.0 cm x 2 in size. 5 cm x 0.12 cm. The filter paper sheets contained an average of 60% humidity. Face joining was performed following the same procedure as Example 1 under compressive strength of approximately 700 N for 5 s and drying was performed following the same procedure as Example 3. In this embodiment, all adhesive joints of the samples were tensile resistant when subjected. controlled mechanical test conditions.
EXEMPLO 7 - PREPARO DE UMA SOLUÇÃO ADESIVA E SUA APLICAÇÃO NA COLAGEM ENTRE UMA TIRA DE PAPEL DE SULFITE E UMA TIRA DE TECIDO DE ALGODÃO.  EXAMPLE 7 - PREPARING AN ADHESIVE SOLUTION AND ITS APPLICATION FOR COLLAGE BETWEEN A SULFITE PAPER STRIP AND A COTTON FABRIC STRIP.
[0066] Esta modalidade da invenção difere dos exemplos anteriores revelados nesta invenção pela adição de um aditivo à solução adesiva. A solução adesiva é preparada pela dissolução de 5% (m/m) de celulose microcristalina de alta pureza comercialmente disponível, oriunda de linter de algodão, em uma solução de 7% (m/m) de NaOH em água, aditivada por 12% (m/m) de uréia. A celulose é adicionada à solução aquosa de NaOH e uréia e homogeneizada a 0°C e 6000 rpm por 10 min. A colagem foi realizada aplicando uma camada de 40 mg da solução adesiva sobre uma área de 1 cm x 2 cm de uma tira de tecido de algodão comercialmente conhecido como popeline, de dimensão 5,0 cm x 2,0 cm, recobrindo totalmente a área de aplicação. Após a aplicação do adesivo, foi realizada a junção da tira de tecido recoberta pelo adesivo com uma tira de papel sulfite de gramatura 75 g/m2 de mesma dimensão. A junção das faces foi realizada sob força compressiva de aproximadamente 1000 N por 10 s. A secagem do corpo de prova colado foi realizada a 24 °C e aproximadamente 40% de umidade por 90 min, posicionado sobre um filme de PE. Após a secagem foi aplicada uma camada de 40 mg de adesivo na face externa do tecido na junta adesiva e foi realizado tratamento térmico a 60 °C e umidade saturada por 30 min. A secagem final do corpo de prova foi realizada a 24°C e aproximadamente 40% de umidade por 90 min, posicionado sobre um filme de PE. Nesta modalidade, todas as juntas adesivas das amostras se mostraram resistentes à tração quando submetidas a condições controladas de ensaios mecânicos. EXEMPLO 8 - PREPARO DE UMA SOLUÇÃO ADESIVA A PARTIR DE POLPA DE BAGAÇO DE CANA E SUA APLICAÇÃO NA COLAGEM DE FOLHAS DE PAPEL FILTRO ÚMIDAS . This embodiment of the invention differs from the previous examples disclosed in this invention by the addition of an additive to the adhesive solution. The adhesive solution is prepared by dissolving 5% (w / w) of commercially available high purity microcrystalline cellulose from cotton linter in a 7% (w / w) solution of 12% NaOH in water. (m / m) of urea. The cellulose is added to the aqueous solution of NaOH and urea and homogenized at 0 ° C and 6000 rpm for 10 min. The bonding was performed by applying a 40 mg layer of the adhesive solution over a 1 cm x 2 cm area of a 5.0 cm x 2.0 cm commercially known poplin strip of fabric covering the entire area. of application. After application of the adhesive, the adhesive-coated fabric strip was joined with a 75 g / m 2 bond of sulfite paper of the same size. The faces were joined under force approximately 1000 N for 10 s. The glued specimen was dried at 24 ° C and approximately 40% humidity for 90 min, placed on a PE film. After drying, a 40 mg layer of adhesive was applied to the outer surface of the fabric on the adhesive joint and heat treated at 60 ° C and saturated humidity for 30 min. The final drying of the specimen was performed at 24 ° C and approximately 40% humidity for 90 min, placed on a PE film. In this mode, all adhesive joints of the samples proved to be tensile resistant when subjected to controlled mechanical testing conditions. EXAMPLE 8 - PREPARING A STICKER ADHESIVE SOLUTION FROM CANE CANE PULP AND ITS APPLICATION FOR COLLATING Damp FILTER PAPER SHEETS.
[0067] Esta modalidade da invenção difere dos exemplos anteriores pela matéria-prima de partida usada na preparação da solução adesiva. A solução adesiva partiu de polpa de bagaço de cana-de-açúcar, preparada previamente por tratamento térmico do bagaço a 130°C em solução aquosa de NaOH 3% (m/v) por 3 h. A polpa úmida de bagaço de cana (umidade 67 %) foi dispersa em uma solução aquosa de NaOH, obtendo-se uma dispersão de 5% (m/m) de polpa de bagaço e 7% (m/m) de NaOH. Os parâmetros de temperatura e agitação para homogeneização foram os mesmos descritos no Exemplo 1. O sobrenadante desta dispersão foi separado por centrifugação a 10000 rpm por 5 min. A colagem foi realizada aplicando 50 pL da fase liquida em uma área de 1 cm x 2,5 cm de tiras úmidas de papel filtro qualitativo de gramatura 80 g/m2 e de dimensão de 10,0 cm x 2,5 cm x 0,12 cm. As folhas de papel de filtro continham em média 60% de umidade. A junção das faces foi realizada seguindo o mesmo procedimento do Exemplo 1 sob força compressiva de aproximadamente 700 N por 5 s e a secagem foi realizada seguindo o mesmo procedimento do Exemplo 3. Nesta modalidade, todas as juntas adesivas das amostras se mostraram resistentes à tração quando submetidas a condições controladas de ensaios mecânicos. This embodiment of the invention differs from the previous examples in that the starting material used in the preparation of the adhesive solution. The adhesive solution was made from sugarcane bagasse pulp, previously prepared by heat treatment of the bagasse at 130 ° C in 3% (w / v) aqueous NaOH solution for 3 h. The sugarcane bagasse wet pulp (humidity 67%) was dispersed in an aqueous NaOH solution, obtaining a dispersion of 5% (w / w) bagasse pulp and 7% (w / w) NaOH. The temperature and stirring parameters for homogenization were the same as described in Example 1. The supernatant of this dispersion was separated by centrifugation at 10,000 rpm for 5 min. The bonding was performed by applying 50 µL of the liquid phase over an area of 1 cm x 2.5 cm of wet strips of 80 g / m 2 qualitative filter paper with a size of 10.0 cm x 2.5 cm x 0. .12 cm. The filter paper sheets contained an average of 60% humidity. The junction of Faces were performed following the same procedure as Example 1 under compressive strength of approximately 700 N per 5 s and drying was performed following the same procedure as Example 3. In this embodiment, all adhesive joints of the samples were tensile strength when subjected to controlled conditions. of mechanical tests.
[0068] Muito embora modalidades particulares da invenção presente tenham sido mostradas e descritas nos exemplos, as concentrações e matérias primas utilizadas para a obtenção do presente adesivo compreendem várias possibilidades de variações para atender necessidades especificas sem se afastar da invenção em seus aspectos originais mais amplos. As modalidades descritas nos exemplos são meramente ilustrativas e qualquer modificação ao longo delas pode ocorrer para um técnico versado na arte. O técnico saberá prontamente avaliar, por meio dos ensinamentos contidos no texto e dos exemplos apresentados, vantagens da invenção e propor variações e alternativas equivalentes de matérias primas que compreendem majoritariamente celulose em sua composição, assim como usos alternativos dos adesivos aqui revelados, sem fugir, no entanto, ao escopo da invenção. Por conseguinte, a invenção aqui apresentada não deve ser considerada limitada quanto às modalidades descritas neste pedido.  Although particular embodiments of the present invention have been shown and described in the examples, the concentrations and starting materials used to obtain the present adhesive comprise various possibilities of variations to meet specific needs without departing from the invention in its broader original aspects. . The embodiments described in the examples are illustrative only and any modification thereto may occur to one skilled in the art. The person skilled in the art will readily appreciate, by means of the teachings contained in the text and the examples presented, advantages of the invention and propose variations and equivalent alternatives of raw materials comprising mainly cellulose in its composition, as well as alternative uses of the adhesives disclosed herein, without escaping, however, to the scope of the invention. Accordingly, the invention presented herein should not be construed as limited to the embodiments described in this application.
REFERÊNCIAS BIBLIOGRÁFICAS BIBLIOGRAPHIC REFERENCES
• Pelton, R. Microgel adhesive for wet cellulose: measurements and modeling. Langmuir, (2012)  Pelton, R. Microgel adhesive for wet cellulose: measurements and modeling. Langmuir, (2012)
• Boxin, Z.; Hyock, J. K. Adhesion of Polymers in Paper Products from the Macroscopic to Molecular Levei — an overview. Journal of Adhesion Science and Technology, 25 (2011) pp. 557-579. • Venditti, R. A.; Lucas, B. E.; Jameel, H. The effects of adhesive properties on the removal of pressure sensitive adhesive contaminants by pressure screens. Progress in Paper Recycling (2007), 16(3) :18-31. • Boxin, Z .; Hyock, JK Adhesion of Polymers in Paper Products from the Macroscopic to Molecular Took - an overview. Journal of Adhesion Science and Technology, 25 (2011) pp. 557-579. • Venditti, RA; Lucas, BE; Jameel, H. The effects of adhesive properties on the removal of pressure sensitive adhesive contaminants by pressure screens. Progress in Paper Recycling (2007), 16 (3): 18-31.
«Bauma-in, M. G. D; Conner, A. H. Carbohydrate Polymers as Adhesives. Handbook of adhesive technology, revised and expanded, Chapter 22. Mittal, K. L and Pizzi, A. (2003) .  Bauma-in, M. G. D; Conner, A.H. Carbohydrate Polymers as Adhesives. Handbook of adhesive technology, revised and expanded, Chapter 22. Mittal, K. L. and Pizzi, A. (2003).

Claims

REIVINDICAÇÕES
1- Adesivo repolpável, caracterizado pelo fato de compreender :  1- Repulpable adhesive, characterized in that it comprises:
0,5% a 35% em massa de celulose (CAS Number 9004-34-6) ou polpa majoritariamente composta por celulose (CAS Number 65996-61-4), total ou parcialmente solubilizada em um meio solvente; e  0.5% to 35% by weight of cellulose (CAS Number 9004-34-6) or pulp mainly composed of cellulose (CAS Number 65996-61-4), totally or partially solubilized in a solvent medium; and
1% a 10% em massa de um ou mais álcalis, total ou parcialmente solubilizados no meio solvente; e  1% to 10% by weight of one or more alkalis, totally or partially solubilized in the solvent medium; and
0% a 30% em massa de um ou mais aditivos, total ou parcialmente solubilizados no meio solvente.  0% to 30% by weight of one or more additives, totally or partially solubilized in the solvent medium.
2- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de estar na forma de solução ou de pasta .  Adhesive according to claim 1, characterized in that it is in solution or paste form.
3- Adesivo, de acordo com a reivindicação 1 ou 2, caracterizado pelo fato de compreender preferencialmente: de 1% a 7% em massa da referida celulose ou polpa maj oritariamente composta por celulose, quando em forma de solução, e  Adhesive according to Claim 1 or 2, characterized in that it preferably comprises: from 1% to 7% by weight of said cellulose or pulp predominantly composed of cellulose, when in solution form, and
de 15% a 20% em massa da referida celulose ou polpa majoritariamente composta por celulose, quando em forma de pasta .  from 15% to 20% by weight of said cellulose or pulp, mainly composed of cellulose, when in paste form.
4- Adesivo, de acordo com a reivindicação 1, caracterizado pelo de compreender preferencialmente de 2,8% a 8% em massa de um ou mais álcalis, total ou parcialmente solubilizados no meio solvente.  Adhesive according to Claim 1, characterized in that it preferably comprises from 2.8% to 8% by weight of one or more alkalis, totally or partially solubilized in the solvent medium.
5- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que a polpa majoritariamente composta por celulose (CAS Number 65996-61-4) é obtida a partir do tratamento de fontes biomássicas lignocelulosicas, tais como eucalipto, algodão e cana de açúcar e outras fontes similares, através de processos químicos, mecânicos ou biotecnológicos . Adhesive according to Claim 1, characterized in that the pulp mainly composed of cellulose (CAS Number 65996-61-4) is obtained from the treatment of lignocellulosic biomassic sources. such as eucalyptus, cotton and sugar cane and other similar sources through chemical, mechanical or biotechnological processes.
6- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que o meio solvente é a água.  Adhesive according to Claim 1, characterized in that the solvent medium is water.
7- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que o álcali é um ou mais dos compostos selecionados do um grupo que compreende hidróxidos de sódio, potássio, lítio, cálcio e amónio, tetrametilamônio, ou aluminatos e zincatos de metais alcalinos .  Adhesive according to Claim 1, characterized in that the alkali is one or more of the compounds selected from the group comprising sodium, potassium, lithium, calcium and ammonium hydroxides, tetramethylammonium, or metal aluminates and zincates. alkaline.
8- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que os aditivos são compostos hidrotrópicos selecionados de um grupo que compreende uréia, tiouréia, etanol, glicerol, mono-, di- e trietanolaminas , dimetilsulfóxido, toluenossulfonatos , xilenossulfonatos , cumenossulfonatos , lignossulfonatos , benzoatos, salicilatos, citratos, acetatos e outros compostos similares .  Adhesive according to Claim 1, characterized in that the additives are hydrotropic compounds selected from a group comprising urea, thiourea, ethanol, glycerol, mono-, di- and triethanolamines, dimethylsulfoxide, toluenesulfonates, xylenesulfonates, cumenesulfonates. , lignosulfonates, benzoates, salicylates, citrates, acetates and other similar compounds.
9- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que os aditivos são óxidos de metais tais como zinco, alumínio, vanádio, estanho e germânio, ou outro composto similar.  Adhesive according to claim 1, characterized in that the additives are metal oxides such as zinc, aluminum, vanadium, tin and germanium, or other similar compound.
10- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que os aditivos são dispersantes tensoativos de qualquer um dos tipos aniônico, catiônico ou não iônico.  Adhesive according to claim 1, characterized in that the additives are surfactant dispersants of either anionic, cationic or nonionic type.
11- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que os aditivos são nanopart ícuias de argilas, óxidos metálicos, carbonatos, fosfatos ou silicatos, ou nanopart iculas de outras naturezas empregadas como agentes de reforço e de melhora de propriedades mecânicas de polímeros. Adhesive according to claim 1, characterized in that the additives are nanoparticles of clays, metal oxides, carbonates, phosphates or silicates, or nanoparticles of other natures employed as reinforcing and mechanical enhancing agents of polymers.
12- Adesivo, de acordo com a reivindicação 1, caracterizado pelo fato de que os aditivos são sólidos neutralizantes, tais como bicarbonato de sódio, bórax, ácido bórico ou qualquer outra substância com ação tamponante em pH neutro, para evitar o manuseio de uma solução fortemente alcalina durante a colagem de um substrato celulósico.  Adhesive according to Claim 1, characterized in that the additives are neutralizing solids, such as sodium bicarbonate, borax, boric acid or any other buffering agent at neutral pH, to avoid handling of a solution. strongly alkaline during bonding of a cellulosic substrate.
13- Uso do adesivo de qualquer uma das reivindicações Use of the adhesive of any one of the claims.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ou 12, caracterizado pelo fato de ser para a adesão ou revestimento de substratos celulósicos selecionados de um grupo que inclui fibra de celulose, mantas e tecidos celulósicos, celofane e seus filmes, celulose regenerada e seus filmes, papel, papelão, papel cartão e embalagens constituídas por celulose e seus derivados, entre outros materiais similares. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterized in that it is for the adhesion or coating of cellulosic substrates selected from a group including cellulose fiber, webs and fabrics cellulose, cellophane and its films, regenerated cellulose and its films, paper, cardboard, paperboard and packaging consisting of cellulose and its derivatives, among other similar materials.
14- Uso do adesivo de qualquer uma das reivindicações 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ou 12, caracterizado pelo fato de ser para a colagem de substratos celulósicos contendo teores de umidade preferencialmente entre 6% e 70%, quando aplicados aos mesmos.  Use of the adhesive of any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterized in that it is for the bonding of cellulosic substrates containing preferably moisture content. between 6% and 70% when applied to them.
15- Uso do adesivo de qualquer uma das reivindicações 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ou 12, caracterizado pelo fato de ser para a formação de juntas adesivas que permitem: a colagem pela face ou topo das superfícies de substratos celulósicos em formas e figuras planas, tais como folhas, lâminas, lenços, absorventes, toalhas, papel higiénico, mantas, tapetes e rolos de papel e de tecido, entre outras formas similares; ou a colagem por encaixe das superfícies de substratos celulósicos em diferentes formas geométricas tais como embalagens com perfis em L, perfis em T e perfis em U, entre outras formas similares. Use of the adhesive of any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterized in that it is for the formation of adhesive joints that allow: gluing face or top surfaces of cellulosic substrates in flat shapes and figures, such as sheets, blades, tissues, tampons, towels, toilet paper, blankets, mats and rolls of paper and fabric, among other similar forms; or bonding of the surfaces of cellulosic substrates into different geometric shapes such as L-shaped, T-shaped and U-shaped packages, among other similar shapes.
PCT/BR2016/050011 2015-01-28 2016-01-22 Repulpable adhesives for cellulosic substrates obtained by cellulose solubilisation or plasticising, and uses thereof WO2016119032A1 (en)

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