WO2007101896A1

WO2007101896A1 - Compound material, method for producing it continuously and its use

Info

Publication number: WO2007101896A1
Application number: PCT/ES2007/000117
Authority: WO
Inventors: Carlos GONZÁLEZ SÁNCHEZ
Original assignee: Crady Eléctrica S.A.
Priority date: 2006-03-06
Filing date: 2007-03-06
Publication date: 2007-09-13
Also published as: ES2281290B1; ES2281290A1

Abstract

The present invention relates to compound materials that comprise thermoplastic polymer and cellulose fibres, to a method for producing them continuously and to the use of said compound materials in the manufacture of various mouldable articles.

Description

COMPOSITE MATERIAL. METHOD FOR CONTINUOUS PRODUCTION AND USE OF THE SAME

FIELD OF THE INVENTION

This invention relates to composite materials comprising cellulosic materials that serve even for moderately demanding applications, such as those in the sectors of manufacture of electrical, electronic and telecommunications material, and can thus replace different thermosetting polymers and fiber reinforced materials. of glass, currently used. Additionally, the present invention relates to a method for the continuous production of said composite materials to which it refers and to the use of said composite materials for the manufacture of various moldable articles.

STATE OF THE TECHNIQUE

Glass fiber reinforced thermoplastics and thermosetting polymers currently used as raw material for the molding of different items in different industrial sectors, such as the manufacturing of electrical, electronic and telecommunications equipment, present several important disadvantages:

1. Thermosetting polymeric materials are not recyclable. In addition, the cycle times for injection molding are long. In the case of laminar molding compounds such as those used in compression molding of thermosetting prepregs (SMCs), a lot of labor is required and the production process is relatively rudimentary and difficult to automate. Therefore, production costs are high.

2. Thermoplastic materials are relatively expensive, difficult to recycle and, their waste, difficult to treat, due to their content of glass fibers, which are not biodegradable. In addition, its density is relatively high (around 2.5-2.8 kg / m ³ ), resulting in molded articles that are heavier than desirable. The abrasion produced by glass fibers in processing equipment is notable, resulting in higher production costs because the change of the various parts of the processing equipment has to be carried out more frequently (eg, the spindles of injection molding machines).

Therefore, there is a need to find polymeric materials without the aforementioned disadvantages and, at the same time, allow to obtain molded products that meet similar or superior requirements to those of molded products manufactured, currently, with the aforementioned raw materials. Among these requirements are, for example, resistance to abnormal heat and fire in the electrical, electronic and telecommunications sector.

In recent decades, a great deal of research has been carried out with the objective of achieving the effective use of cellulosic materials such as fillers and reinforcements in polymer matrix composite materials. Cellulosic materials are composed of different types of particulate fillers and reinforcements derived from a multitude of plant species and tree or wood species, whose main components are cellulose, hemicellulose and lignin, among others. Cellulosic materials have some important advantages over inorganic materials such as talc, mica or glass fibers, traditionally used as fillers and reinforcements in polymer matrix composite materials. Mainly, these advantages are: lower density, lower cost, less abrasion of processing equipment, biodegradability and renewable character. However, cellulosic materials have several disadvantages:

1. Very limited thermal stability, which results in a substantial thermal degradation thereof at the processing temperatures commonly used for thermoplastic materials. Said stability depends on the nature or origin of the cellulosic material and the process followed for its isolation or obtaining. Thus, cellulose fibers from tree species have a higher thermal stability than cellulose fibers from plant plants, which lose a large part of their resistance at temperatures above 160 ⁰ C. In addition, cellulose fibers obtained by following Different insulation processes - processes for obtaining cellulose pulp - have different thermal stability. The Thermal degradation suffered by the cellulosic material impairs the properties of the composite materials finally obtained.

2. Most cellulosic materials have a polar nature and, therefore, are hydrophilic, due to the presence of hydroxyl groups in their chemical structure, while some of the polymers used as matrices for composite materials (polyolefins) are non-polar. and, therefore, hydrophobic. Therefore, the chemical compatibility between the polymer matrix and the cellulosic material used as filler or reinforcement tends to be low. Said low compatibility results in a poor dispersion of the cellulosic material within the polymer matrix. On the other hand, this low compatibility results in a weak interface between the polymer and the cellulosic material, which results in a poor transfer of effort between the polymer matrix and the cellulosic material, thus damaging the properties of the composite material and restricting Your possible applications.

Therefore, considerable scientific research has been dedicated to the solution of the aforementioned drawbacks and to the combination of different types of cellulosic and polymeric materials in different proportions to give rise to different formulations of composite materials in order to improve the properties of Composite materials obtained and expand its potential spectrum of applications. Taking into account this spectrum of potential applications, the developed composite materials can be divided into two groups: 1) Composite materials whose main component is a cellulosic material. 2) Composite materials whose main component is a polymer. Depending on the type of cellulosic materials and polymers used, their relative proportion in the composite material and the formulation of the composite material as a whole, the methods of obtaining the composite materials and their potential applications can vary widely.

The prior art includes various formulations of composite materials based on cellulosic materials from a multitude of potential sources of raw materials (cellulosic, virgin or residual fibers, from plant or herbaceous plants, or tree or wood species). In relation to the objects of this patent, the most relevant attempts of the prior art state, for Solving the problems encountered in trying to combine different types of polymers and cellulosic materials, include different approaches.

Thus, patent application WO9605347 in the name of SKILLICORN, describes a series of formulations of composite materials composed of cellulose fibers of different plant plants (among others, jute or kenaf) and a thermoplastic selected from the group of polypropylenes or polyethylenes. This invention provides a multitude of applications for these formulations of composite materials: packaging, small appliances, furniture, building materials, automotive products, among many others. Also, in accordance with said invention, the composite materials disclosed by it can be transformed by injection molding, compression molding, extrusion, rotational molding or blow molding. According to the method disclosed in said invention, different techniques can be used to mix between 20 to 60%, by weight, of cellulose fibers coated with a malleable polypropylene, with 80 to 40%, by weight, of polypropylene. These techniques include cold compression and pelletizing devices, the Banbury mixer, the Farrell continuous mixer or the single-screw and twin-screw extruders. One of the objectives of the method used to obtain the composite material is to maximize the slenderness -relation length / diameter- of the fibers. With this objective and in order to maintain an adequate dispersion of the fibers in the composite material, the use of less intensive mixers such as continuous kneaders or appropriately configured double screw extruders is recommended.

The EP0426619 patent to ICMA SAN GIORGIO describes a method for the continuous production of mouldable panels obtained from a polymer with high melting temperature (T _your _ng> 150 ° C) and a thermosensitive filler by direct extrusion using a corroding double screw extruder. The method corresponding to the invention comprises the use of three or, preferably, four helical extrusion sections for transport or effective feeding, and two or, preferably, three interposed kneading sections. The cylinder or chamber of the extruder used in said invention has three openings or ports. The first opening serves to feed the polymer. The second opening serves to feed the heat-sensitive filling and the third opening for venting or degassing. The spindles of the extruder of the invention consist of helical extrusion sections, which have a typical angle, shape and depth of channel, but not considered critical. The distance between the cylindrical spaces defined by the rotation of the spindles of the extruder and the integral mixing and extrusion space varies between 0.2 and 2 mm.

EP0611250 in the name of ICMA SAN GIORGIO describes a method for the extrusion of composite materials based on low melting temperature polymers (T _fUs _ón <150 ° C) for the continuous production of typical semi-finished products, such as PVC panels The method described in patent EP0611250 is very similar to that described in patent EP0426619, but, as the applicants for patent EP0611250 stand out, the use of low melting point polymers is not mentioned in patent EP0426619.

WO 9956936 in the name of INST VOOR AGROTECH ONDERZOEK, SNIJDER MARTINUS HENDRICUS VER, KEMENADE MATHEA JOHANNA JOSEPH and BOS HARRIETTE LOUISE describes a process for the continuous manufacture of composite materials composed of a thermoplastic polymer and cellulose fibers, using an extruder of double corroding spindle, whose spindles rotate at a speed of 200 rpm. According to this invention, thermoplastic polymers that can be used to make composite materials comprise so-called general-purpose plastics, such as polyolefins and polystyrene, or engineering plastics. In addition to virgin thermoplastics, recycled thermoplastics can also be used instead. It is also preferred to add a coupling agent to the polymeric material. The preferred ratio of polymer to coupling agent for a polyolefin matrix (eg, polyethylene, polypropylene) is 70 to 6, with the most preferred ratio being 8 to 16, by weight. Preferred coupling agents for such matrices are polyethylenes grafted with maleic anhydride or polypropylenes grafted with maleic anhydride, depending on the type of matrix used. Other additives, such as pigments, antioxidants, flame retardants and fillers such as talc, calcium carbonate and carbon black, can also be added to the polymer. The pellet of composite material obtained following the process indicated in the patent is considered suitable for obtaining articles by injection molding and compression molding. Also, as indicated by this invention, it is possible to directly mold the composite material obtained in the form of plates, tubes or profiles. Items obtained from Composite material obtained can be used to replace wood, plastic and, alternatively, composite materials with different fillers and reinforcements. The authors of WO 9956936 highlight the importance of slenderness and the length of the fibers to obtain composite materials with good mechanical properties. Accordingly, they recommend the use of annual plant fibers or fibers of the stem bark of annual plants, such as flax, hemp, jute and kenaf, due to their high length and high slenderness (length / diameter ratio). They indicate that it is also possible to use a combination of different types of fibers, such as recycled paper fibers and fibers of the bark of the stem of annual plants. They also emphasize that the process revealed by the patent is advantageous because the individual or elementary fibers retain their high slenderness and length. In accordance with the invention, the location of the zones of the extruder is calculated from the head of the same, because it is important that the fiber feeding port is located as close as possible to the end of the extruder. Therefore, cellulose fibers are introduced into the melt as late as possible, so that they are minimally affected by friction and heat. The extruder claimed by the invention comprises all extruders with two separate feed ports and a degassing port. The extruder claimed is divided, according to the authors of the invention, into four zones: a first zone where the polymer is fed, a second zone where the cellulose fibers are fed, a third zone for venting or degassing and a fourth zone in where the pressure is increased.

Patent application US 5288772 in the name of Clemson University provides a thermoplastic formulation reinforced with cellulose fibers that allows the production of composite materials. Another object of said patent is to provide a method to use residual cellulosic and thermoplastic materials. In accordance with said invention, the thermoplastic resin present in the composite material can be any thermoplastic (polyolefins, vinyl polymers, polyamides, acrylic resins and styrene resins). The cellulosic materials included in said invention can be any material containing cellulose fibers (newspapers, cardboard, wood fibers, scratches, cottons, ramie, jute, bagasse, among many others). According to the invention, to ensure that the fibers and thermoplastics give rise to a sufficiently coherent mass, lignin can be added to the formulation, as well as independent component, or already forming part of the cellulosic materials themselves. Another object of the patent is to provide a method for obtaining said composite materials. According to said method, thermoplastic resins are heated in a mixing device until a molten matrix is obtained. Then, while stirring the molten matrix of thermoplastics is continued, the cellulosic materials are added thereto, maintaining the selected temperature.

US5516472 in the name of STRANDEX describes a composite material comprising a polymer and cellulosic fibers, as well as the process and the machine for manufacturing said product. The composite material is characterized by having a high content of cellulose fibers (more than 50%, by weight). According to the authors of the patent, using the continuous low temperature extrusion process revealed by the patent, the material could have up to a 1: 0 fiber / thermoplastic ratio.

EP799679 in the name of AIN ENGINEERING KK refers to a method for achieving a drawing, such as a wood grain with the appearance of natural wood, on the surface of a synthetic board. Said board is constituted by a mixture containing between 20-65%, by weight, of a wood flour, and 35-80%, by weight, of a thermoplastic. If the thermoplastic used is polypropylene or polyethylene, the preferred content of wood flour varies between 50-55%, by weight. The synthetic board is manufactured by extrusion, using a single or multi-spindle extruder.

Patent application US2003 / 00301176 in the name of THERMO FIBERGEN presents as a novelty that high levels of sludge from papermaking can be mixed (eg, up to 70-75%), transformed into granules by wet way, with plastic and , if desired, cellulose fiber, to obtain composite materials. The authors of the invention indicate that, surprisingly, despite the low relative levels of plastic, composite materials have good mechanical properties (high strength, high modulus, high impact resistance, among others). These mechanical properties make the composite materials object of the patent useful as raw material for the manufacture of different products, such as roof tiles, fences, door panels, acoustic screens, roofing materials, decorative wall coverings and similar applications. However, the examples show that the mechanical properties of composite materials are poor. Thus, for example, its resistance to bending does not exceed 17,34 MPa (2,500 psi) and its modulus of elasticity to bending does not exceed 2,9 GPa (418,000 ps¡), in the best cases. These poor mechanical properties already represent, on the one hand, an important limitation in the applications in which these composite materials can be used. On the other hand, they negatively affect the geometry of the products to be manufactured which, as a consequence, must have greater wall thicknesses to achieve the necessary stiffness, which implies a greater material expense, a greater weight of the piece and, in Definitely, a higher cost.

According to the description of said patent application, the sludge from the manufacture of cellulose, lignin, hemicellulose, calcium carbonate, clay and other inorganic components paper. In many cases, the ashes of the sludge from papermaking total up to 50% (and in some cases, up to 80% or more) of the volume of sludge. The main components of the ashes are calcium carbonate (20-75% of the dry mud) and clay. These two minerals are commonly used in paper as a coating and a filler to improve its mechanical characteristics as well as its appearance. More specifically, the granules (BIODAC brand), obtained by wet transformation of the sludge of papermaking, used as raw material, in combination with rice husk, to obtain the composite materials object of the patent are composed of: Paper fiber (CAS # 9004-34- 6): 47-53%; Kaolin: 28-34% (CAS # 1332-58-7); Calcium carbonate (CAS # 471-34-1): 14-20%. Titanium dioxide (CAS # 13463-67-7): <1%. Its density ranges from 0.64-0.768 g / cm ³ and its granulometry can be 10/30 meshes (0.590-2,000 mm) or 12/20 meshes (0.840-1, 680 mm) or 20/50 meshes (0.297-0.840 mm) . The composite material can also contain, together with the granulated sludge of papermaking, different types of cellulose fibers from different sources: short fibers of agricultural origin; fibrous plant materials; fibers from the processes of textile fiber production and processing operations of cellulose pulp and paper; fibers from the recycling processes of paper and wood products, etc. In one of the embodiments of said invention, the organic material of the composite material comprises the granulated sludge, alone or in combination with cellulose fibers. Agree With the invention, a further ecological benefit can be achieved by combining the granulated sludge with recycled plastic. In the formulation of the composite material, reinforcing agents, lubricants, colorants, compatibilizers and / or flame retardants can also be included, at levels consistent with well known applications of the composite materials. The authors of the invention indicate that the final product of this patent -the composite material- can be transformed, preferably, by extrusion, injection molding or compression molding. However, the examples shown in the patent refer exclusively to the transformation of composite materials by extrusion to obtain products whose minimum wall thickness is 0.25 inches (6.35 mm). No mention is made in the patent to which are the rheological properties of the composite materials object of the invention. Said properties totally condition their possibilities of transformation into real products of different thicknesses - in many cases smaller than those indicated in the patent -, especially in the case of their transformation by injection molding.

According to the description of the THERMO FIBERGEN patent, the claimed composite material is manufactured by mixing certain amounts of its components to give rise to a homogeneous mixture, which is then fed to a twin screw extruder. Thus, the method followed to manufacture the composite material involves the prior obtaining of a homogeneous mixture of the components of the composite material, instead of its direct separate feeding to the extruder, which represents a further stage in the process of obtaining and Higher production cost. The resulting composite material is pelleted and fed to a single screw extruder to shape the final product. According to the authors, the invention provides, on the one hand, new and effective composite materials, and on the other hand, a new use for the pulp and paper sludge. They also indicate that, according to their invention, the new composite materials can be used, in general, for a wide variety of specific applications. Moreover, the authors mention that the composite materials of their invention can be made flame retardant. However, in its patent there is no reference to the way in which it is to be operated to obtain said interesting property, nor to the types of articles that could be manufactured using those fire-retardant composite materials. Patent application WO01 / 83195 in the name of DAVIS STANDARD CORP, MURDOCK DAVID E., SNEAD DALE K, DARDENNE DARRELL S. and MILLS IAN W. describes an extrusion process for the manufacture of plastic matrix composites containing particles of wood or wood fibers, whose humidity can be variable and / or high. In accordance with this invention, the wood fibers can come from soft wood species -conifers- and / or hardwood species -frondosas-, being the most popular for obtaining profiles, pine, maple and oak. In addition to wood fibers, organic fillers, such as grass residues, agricultural residues, natural fibers from land or aquatic plants, can also be used. The process revealed by this patent, uses a double screw spindle extruder to dry the organic filling, as well as at least a second extruder to melt the polymer and feed it into the cylinder of the first extruder. In accordance with this patent, the process corresponding to the invention uses spindle rotation speeds and shear speeds, lower than traditional equipment and processes.

Thus, the state of the existing technique describes various formulations of composite materials that are suitable for a multitude of applications. However, none of these formulations of composite materials meets the requirements set to the raw materials currently used for some moderately demanding applications, such as those in the sectors of manufacturing of electrical, electronic and telecommunications equipment, or others such as The construction, aviation, automotive, furniture and packaging. In fact, there is no commercial product of the type disclosed in the state of the art that meets the requirements set to the materials used for the aforementioned applications.

The extrusion-mixing processes with twin-screw extruders corrotantes, used to obtain different composite materials, according to the prior art, are very similar. These processes differ in very small details that, taking into account the number of patents granted, are those that condition the obtaining of the desired composite materials and products intended for those composite materials. That is, small changes in the extrusion-mixing processes allow the obtaining of different composite materials, with different properties and different possible applications. As described above, in the state of the art various virgin and recycled plastics are proposed as matrices for the manufacture of composite materials reinforced with cellulose. However, no reference is made about what specific characteristics these plastics should possess in order to be used in the production of the composite materials and the products claimed by the patents corresponding to the prior art. Specifically, there is no reference to what morphology and rheological properties they should possess in order to be used, nor what specific characteristics the feeding equipment of said plastics should have for its continuous and adequate dosage to the production line of composite materials.

The prior art state places all cellulosic fibers within a broad and general category. However, the chemical composition, the thermal stability and the morphology of the cellulosic fibers depend on their nature or origin and the process followed for their isolation and obtaining. Thus, cellulosic fibers of tree or wood species are different from cellulosic fibers from plant plants. Cellulosic fibers from soft wood tree species - whose lengths are between 0.7-1.6 mm approximately - differ from those that come from hardwood tree species - whose lengths are between 2.7-4, 6 mm, approximately. Likewise, the cellulosic fibers of plant plants - whose lengths are between 0.7-250 mm approximately - differ from each other. On the other hand, residual cellulosic fibers differ from virgin cellulose fibers. In addition, the cellulosic fibers obtained by different insulation processes (e.g., the different mechanical, chemical and chemical thermomechanical processes for obtaining cellulose pulp), bleaching processes and refining processes, have different characteristics.

On the other hand, the type of treatments to which the cellulosic fibers can be subjected to be obtained in the desired final form also affects their quality. As a whole, all these factors mentioned condition the morphology of the individual fibers and the characteristics of the agglomerates that they can form (that is, their morphology and apparent density). In turn, all these factors condition the possibilities of continuously feeding and dosing cellulosic fibers to mixing equipment with molten polymers that can allow the obtaining of composite materials, as well as the properties of the composite materials themselves. The prior art does not take into account that the means necessary for dosing the longer cellulose fibers, which are presented in the form of skeins or strands, are different from the means necessary for dosing shorter cellulose fibers. Specifically, it is ignored that the greater the length of the fiber, the greater the entanglement that occurs between the fibers and the lower the apparent density of the agglomerates they form. The lower the apparent density of these agglomerates, the more difficult it is to feed the equipment for obtaining composite materials, which results in the quality and properties of the composite materials thus obtained being variable and, in addition, it is not possible to reach the production rates required by the industrial scale production.

Moreover, the longer fibers give rise to composite materials with a higher viscosity and a variable rheological behavior, which makes their transformation into different articles difficult by means of the most common molding processes such as injection molding. Mixtures of fibers of different nature and origin cannot be subtracted from the aforementioned problems and limitations and require adequate technology to enable their effective use as a cellulosic raw material in polymeric matrix composites.

The problems mentioned above are very relevant, and condition the achievement of a suitable and practical technology for the manufacture of polymer matrix composite materials with cellulosic materials and the products that correspond to their applications. Thus, the practical and effective use of the multitude of cellulosic materials cited in the prior art state, tends to be less than what is indicated therein, when real and moderately demanding industrial applications are contemplated for that type of composite materials. This is because its use can compromise, not only the properties of composite materials, but the process of obtaining composite materials, due to the different problems that each type of cellulosic material presents. Additionally, when the applications that are the direct object of this patent or that are suggested by it are contemplated For this type of composite materials, there are no specific formulations or mixing methods that are suitable for the processing of the corresponding raw materials. As a result, the potential benefits offered by the formulations of composite materials indicated so far remain limited, in what refers to really available materials and products, environmental benefits and costs.

It is an object of the present invention to provide new thermoplastic matrix composite materials comprising cellulosic materials. These new materials make it possible to replace thermosetting polymers and glass fiber reinforced materials, currently used in various sectors, such as the manufacturing of electrical, electronic and telecommunications equipment. It is also the object of the present invention to provide a new method for the continuous production of said composite materials, as well as some of the molded products that can be manufactured using said composite materials as raw material. Thus, the technology described in this application allows obtaining, in a technical and economically viable way, new thermoplastic matrix composite materials comprising cellulosic materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The description of the present invention will be carried out below with the help of the following figures:

Figure 1 is a side view of an installation used in the method according to the present invention for obtaining the composite material. Figure 2 represents a side view of the corroding extruder with an illustration of the types of spindle elements that can be inserted on each of the mandrels thereof to give rise to different spindle configurations.

Figure 3 shows a fuse holder base for blade fuses made of the composite materials object of this invention. Figure 4 shows a fuse holder base for cylindrical fuses made of the composite materials object of this invention.

Figure 5 shows the body of the closed vertical tripolar bases manufactured with the composite materials object of this invention. DESCRIPTION OF THE INVENTION

Therefore, according to a first essential aspect, the present invention refers to a composite material that, for every 100 parts of its weight, comprises: (A) between 25 and 90 parts, by weight, of a thermoplastic polymer; (B) between 1 and 50 parts, by weight, of a cellulosic material, (C) between 0.1 and 15 parts, by weight, of a coupling agent; (D) between 0.05 and 3 parts, by weight, of a primary antioxidant; (E) between 0.05 and 6 parts, by weight, of a secondary antioxidant (F) between 1 and 40 parts, by weight, of a flame retardant, characterized in that said cellulosic material (B) comprises fibers that are selected from the group formed by virgin cellulose pulp fibers from hardwood tree species, fibers obtained as waste from the pulp and paper industry, fibers obtained as waste from the synthetic and textile fiber manufacturing industries, fibers from solid urban and industrial waste or mixtures thereof.

According to a preferred embodiment according to the present invention, said thermoplastic polymer (A) is a polyolefin, which is selected from the group consisting of polypropylene homopolymers, propylene copolymers, polypropylene-polyethylene vinyl acetate (PP) + EVA), high density polyethylene, low density polyethylene), a polystyrene (which is selected from the group of its homopolymers, copolymers or terpolymers), polyvinylchloride (PVC), a polymer from the polyamide group, poly (ethylene glycol terephthalate) (PETP), poly (butylene glycol terephthalate) (PBTP), poly (methyl methacrylate) (PMMA) or polycarbonate (PC) or mixtures thereof. The preferred virgin polyolefins for carrying out this invention are polypropylene homopolymers and copolymers of controlled rheology with similar melting points and flow rates ranging from 12 to 150 g / 10 minutes (according to ISO 1133, at 230 ⁰ C and 2 , 16 kg).

According to another preferred embodiment according to the present invention, said thermoplastic polymers come from industrial waste from the transformation of plastics (eg, any polypropylene, polyethylene, polystyrene or polypropylene co-polyethylene-vinyl- acetate (PP + EVA)) or of the comment of urban solid waste. The latter are mainly different mixtures of polypropylene and polyethylene available, initially, in the form of irregularly shaped and sized scales.

The recommended coupling agents (C), in accordance with the present invention, are those belonging to the group of polyolefins grafted with maleic anhydride, said polyolefins having number average molecular weights between 2000 and 50,000 or mass average molecular weights comprised between 4000 and 300000, and having maleic anhydride contents comprised between 0.1 and 20%, by weight; pure or modified polyethyleneimines whose molecular weights vary between 800 g / mol-g and 200000 g / mol-g, which are presented as anhydrous products or not; aromatic and aliphatic organosilanes or mixtures thereof.

On the other hand, preferably, the composite material according to the present invention comprises cellulose fibers from hardwood tree species, such as Eucalyptus globulυs. Said cellulose fibers may be virgin cellulose pulp fibers, either raw, bleached or refined. The virgin raw cellulose pulp fibers have the following approximate composition (on a dry basis): 97%, by weight, holocellulose, 2.5%, by weight, lignin and 0.5%, by weight, ash. Virgin bleached or refined cellulose pulp fibers contain cellulose, for the most part, and very small proportions of lignin and hemicelluloses.

According to a preferred embodiment according to the present invention said fibers obtained as residues of the pulp and paper pulp industry can be residual pulp pulp fibers of the pulp pulp production processes from wood species, from the rejections of the sieving processes of the mixture of cellulose fibers and black liquor leaving the digesters, of the final rejections of the purification processes of the cellulose pulp, and of various losses and leaks through the fabrics of the scrubbers used in the different phases of the bleaching of the cellulose pulp and through the sheet-forming fabric in the window dressing machine. Said residual cellulose pulp fibers, after being subjected to filtration and compaction, are presented in the form of agglomerates with a humidity comprised between 50-70%, by weight, and which may also contain "uncooked". Said agglomerates have the following approximate composition (on a dry basis): between a 5 and 20%, by weight, of ashes, between 5 and 20%, by weight, of lignin and between 55 and 90%, by weight, of holocellulose, and presented in the form of planar agglomerates of form and irregular contours, whose diameter equivalent to its projected area is essentially less than 67 mm, whose sphericity is between 0.5 and 0.9, and whose roundness is between 0.3 and 0.7, its bulk density being between 0 , 08 and 0.380 g / cm ³ . For these purposes, diameter equivalent to the area projected by the agglomerate is understood to be that diameter of the circle of the same area as that projected by the particle agglomerate in a stable position. Sphericity is understood as that relationship or quotient between the area of the surface of the sphere with the same volume as the agglomerate and the area of the surface of the agglomerate. Roundness is understood as that relationship or quotient between the perimeter of the circle with the same area as the area projected by the agglomerate in a stable position and the actual perimeter of the particle projected in a stable position. "Incocided" pieces of wood are understood to be not defibrated during the cooking of the wood that takes place in the process of obtaining the cellulose pulp or fiber packages that did not dissolve during said cooking.

According to another preferred embodiment, said fibers obtained as residues of the pulp and paper industry are the residual cellulose fibers from the industrial processes of manufacturing cellulose pulp from plant plants selected from the group that includes jute, abaca, sisal, hemp, flax, or mixtures thereof.

According to another preferred embodiment according to the present invention, said cellulose fibers from the rejections of the manufacturing processes of synthetic and textile fibers are selected from the group consisting of cellulose fibers from the rejections of the manufacturing processes of synthetic fibers. (eg, cellulosic fiber threads - viscose and rayon threads -, etc.), cellulose fibers obtained from the recycling of spent textile products (for example, clothing, household textiles-clothing of household-, sanitary material-bandages, dressings-, protective garments, cleaning material), or residual cellulose fibers from industrial manufacturing processes of non-woven fabrics (for example, those in which non-woven fabric It is made using a hydraulic interlacing process in which jets of High speed water seals the cellulose fibers resulting in a high technical performance fabric).

According to another preferred embodiment according to the present invention, said cellulose fibers from urban and industrial solid waste are residual cellulose fibers from the urban solid waste stream (cellulose fibers from used paper and cardboard) or the residual fibers of cellulose from the recycling processes of paper and cardboard used (eg, newspaper, magazine, cartons for liquids from complex containers with plastic and aluminum, etc.), provided that, mainly, they belong to the type of Cellulose fibers indicated above, or having a length and slenderness - length / diameter ratio - similar to those of the cellulose fibers indicated above.

The length and slenderness of the cellulose fibers, used as raw material, are preferably similar and constant within a range. The extent of said range depends on the characteristics of the specific embodiment of the method used to obtain the composite materials object of this invention.

Optionally, said cellulosic material (B) comprises cellulosic fibers with individual lengths between 0.1-10 mm, individual fiber diameters between 0.01-50 μm, and individual length / diameter ratios between 2-250.

According to another preferred embodiment according to the present invention, the recommended primary antioxidants are those belonging to the group of sterically hindered phenols with molecular weights greater than 300 g / mol, cinnamates, amines or mixtures thereof.

In accordance with another preferred embodiment according to the present invention, the secondary antioxidant (E) is selected from the group consisting of phosphorus compounds, thioethers, thioesters, preferably thioethers, or mixtures thereof. Preferably, the flame retardants (F) are selected from the group consisting of the compounds belonging to the category of phosphorus compounds, chlorinated compounds, brominated compounds or mixtures thereof. Optionally, the flame retardants (F) indicated above can also be combined with one of the following synergistic components: aluminum trihydroxide, hydrated aluminas, borates, stannates, magnesium hydroxide, antimony oxide (III) and compounds belonging to the category of nitrogen-containing compounds.

According to another preferred embodiment according to the present invention, said composite material comprises at least one lactone.

According to another preferred embodiment according to the present invention, the composite material additionally comprises between 0.1 and 40%, by weight, with respect to the total weight of the composite material, of an additive (G) that is selected from the group formed by the stabilizers to light or UV stabilizers, modifiers of impact properties, inorganic fillers, lubricants, pigments, biocides and foaming agents or mixtures thereof. The additives (G) can be used to improve some of the properties and processability of the composite materials that constitute one of the objects of the present invention, provided that the final application of the composite material requires it. Preferably, the light stabilizers are lignin, carbon black and those belonging to the groups of the bénzófenoήas, bénzotriazoles and the triazines. The content of said light stabilizers in the composite material can be comprised between 0.1-10%, by weight, with respect to the total weight of the composite material. Preferably, the modifiers of the impact properties are those belonging to the group of ethylene and propylene copolymers, including grafted copolymers of ethylene and propylene, terpolymers of ethylene, propylene and non-conjugated diene monomers, and polybutenes. The content of said modifiers of the impact properties in the composite material may be between 1 and 30%, by weight, with respect to the total weight of the composite material. In accordance with a preferred embodiment according to the present invention, the lubricants are those belonging to the group of the derivatives of long main chain fatty acids, amide waxes, natural paraffins, waxes of low molecular weight polyolefins, stearates, siloxanes, and even fluorothermoplastics The specific lubricants to be used and their dosage levels depend on the specific production scale of the industrial process and on the specific application in which the composite materials are used. One of the advantages of the new composite materials according to the present invention is that they fulfill the requirements corresponding to the articles of the sectors of manufacture of electrical, electronic and telecommunications equipment. In summary, among others, these requirements are: • Mechanical rigidity sufficient to resist the removal of any electrical component (eg, a fusible cartridge) without breaking or cracking, both at room temperature and after being subjected to heating at a temperature of 80 + 5 ⁰ C.

• No deterioration of the insulating parts after being subjected to continuous heating at a temperature of 155 ± 5 ⁰ C for 168 hours.

• Insulation resistance not less than 5 Megaohms; after being subjected to a continuous voltage of 500 V.

• Resistance to the formation of conductive paths after subjecting the material to a drip with a conductive solution of anhydrous ammonium chloride and sodium dibutyl naphthalene sulfate and subjecting it to a voltage of 600V.

• Verification of the heating of the carrier assembly and dissipable power that involves subjecting the articles manufactured with the composite material to its nominal intensity.

• Fusion test to check the resistance of the material to severe working conditions. • Resistance to abnormal heat and fire, which means that after contacting the manufactured articles with the composite material, an incandescent wire at a temperature of 960 ⁰ C for 30 seconds, the flame produced must be extinguished before the next 30 seconds .

• Degree of protection equivalent to IP203 (protection against the entry of solid bodies, water and resistance to mechanical impacts with a standardized pendulum).

• Dielectric strength sufficient not to suffer perforations or contours after being subjected to a normalized voltage at industrial frequency.

• present a lower footprint to 2 mm after being subjected to a standard point - shaped weight in an oven at 125 ⁰ C for 1 hour. • Resistance to corrosion in salt spray atmosphere, the material does not deteriorate, after exposure for 336 hours. The formulations of the composite materials object of this invention cover the future demand for environmentally sustainable materials, due to their high content of renewable fibers and compounds that are not harmful to the environment.

In accordance with a second essential aspect, the present invention refers to a new method of obtaining the new continuous composite materials, which allows the effective use of different types of cellulose fibers (virgin or residual) for obtaining different Composite material formulations. Such formulations are suitable, even, for demanding applications, such as those in the manufacturing of electrical, electronic and telecommunications equipment. Said new method for obtaining the new composite materials with cellulosic materials comprises the following steps: a) drying the cellulosic material object of the present invention rb) providing a corroding double screw extruder, which comprises two mandrels (3), in each of which an identical spindle configuration is mounted using different spindle elements, the ratio between its external and internal diameter being between 1, 02 and 2; c) mix the components of the composite material; and d) discharge the resulting composite material through a discharge zone (4) which extends along a length between three and seven times the diameter of the extruder.

Step a) consists in subjecting the cellulosic material to drying, preferably, to a moisture content of between 1 and 10%, by weight, for which any of the commercially available drying technologies can be used. In the case of some cellulosic materials that can be used as raw materials in this invention, an additional step may be required which comprises the transformation of the previously dried cellulosic materials into agglomerates with a size and shape suitable for continuous feeding to the equipment. of melt phase mixing in which the composite materials object of this invention are obtained. Preferably, the cellulosic materials are transformed into planar agglomerates of irregular shape and contour, whose diameter equivalent to their projected area is essentially less than 15 mm, whose sphericity is between 0.3 and 0.7, and whose roundness is comprised between 0.1 and 0.7, suitable for continuous feeding. The double screw extruder used in the present invention can comprise at least two separate feeding ports and at least one degassing port and can have up to 10 openings or separate ports. Three of these ports are preferably suitable for feeding different raw materials in solid state. Four of these ports are preferably suitable for feeding raw materials in liquid phase, and the other three ports are preferably suitable for atmospheric venting, or by vacuum, of various gaseous products. This method allows the control of the length and slenderness -relation length / diameter- of the cellulose fibers, in order to optimize the properties of the composite materials that are also the object of this invention.

In step d) according to the present invention, the resulting composite material leaves the extruder through a discharge head (5), after which it can undergo various transformation processes. When the composite material in the form of a pellet is desired, a cord extrusion head is placed. Preferably, the pelletizing methods are the cord granulator or the head knife granulator with air cooling or air-water mixtures. The composite pellet thus obtained is capable of being fed to an industrial injection molding machine in order to obtain molded products.

In accordance with a preferred embodiment according to the present invention, the composite material, after passing through the discharge zone (4) and being subjected to a granulation process, is subjected to an injection molding process. Preferably, the composite pellets is injected at a temperature lower than 210 ⁰ C in any of the heating zones of a chamber or plasticising cylinder of a molding machine injection.

Optionally, said composite material is subjected to a calendering process as it leaves the discharge zone (4) in order to have a thin panel, followed by compression molding. In accordance with another preferred embodiment according to the present invention, the composite material is subjected to a direct extrusion process after passing through the discharge zone (4).

In stages b) and c), the necessary adjustments are made on the same extruder preparing an optimal spindle configuration for obtaining a composite material with the characteristics appropriate to each application. The spindle configuration chosen depends on the characteristics of the thermoplastic to be fed to the extruder (such as morphology and fluidity index) and the characteristics of the cellulosic material to be fed to the extruder (such as length and slenderness of its cellulose fibers). It also depends on the mechanical and rheological properties that the composite material to obtain must have, which, in turn, depend on the requirements of the final application in which the composite material is to be used. Therefore, in accordance with a preferred embodiment according to the present invention, the mixing stage c) comprises the following steps: i.- dosing through a feed hopper '(6) the thermoplastic polymer (A), the agent coupling (C), the primary antioxidant (D) and the secondary antioxidant (E) and, optionally also the additives (G) that are selected from the group consisting of light stabilizers or UV stabilizers, modifiers of the impact properties, inorganic fillers, lubricants, pigments, biocides and foaming agents, by means of a set of gravimetric dosers (2), within a feeding zone of the polymer and additives (7), which comprises positive transport spindle elements and extends to The length of a length between three and seven times the diameter of the extruder; i¡.- heating the mixture obtained in step i.- and transporting said mixture along a closed transport and heating zone (8) comprising positive transport spindle elements;

¡¡I.- melt, mix and knead said mixture in a melting zone (9), which comprises kneading spindle elements, the joint length of the closed transport and heating zone (8) and of the mixing zone being included. fusion (9) between three and seven times the diameter of the extruder; iv.- subject the previous mixture, through the atmospheric venting port (11), to venting and degassing in a first venting zone (10) comprising spindle elements of negative or reverse transport and positive transport; v.- continuously dosing the cellulosic material (B) in a lateral feeding zone of the cellulosic material (12) comprising positive transport spindle elements, using a first double spindle stuffing with spindles that must have a minimum external diameter 24 mm (13), in turn fed by a second double screw gravimetric dispenser (14) disposed above said first stuffer, the joint length of the first vent zone (10) and the lateral feed zone being comprised of the cellulosic material (12) between three and eight times the diameter of the extruder. vi.- kneading the mixture obtained in the previous stage v.- in an area of incorporation of the cellulosic material and liquid injection (15) comprising at least one kneading spindle element or at least one toothed mixing element, or at less a positive transport element, or at least one negative transport element or a mixture thereof, said area extending along a length between three and seven times the diameter of the extruder; vii.-submit the mixture obtained in the previous stage vi.- through a second atmospheric venting port (17), to venting and degassing in a second venting zone (16) comprising transport and transport spindle elements positive; viii.- continuously dosing a flame retardant (F) in a side feed zone of the flame retardant (18) comprising positive transport spindle elements using a second double spindle stuffing chamber with chamber and preferably chilled spindles (19) , said spindles having a minimum external diameter of 20 mm, fed in turn by a third double spindle gravimetric dispenser (20) disposed above said second stuffer (19), the joint length of the second venting area being comprised

(16) and of the side feed zone of the flame retardant (18) between three and eight times the diameter of the extruder. ix.- kneading the mixture obtained in the previous stage viii.- in a zone of incorporation of the flame retardant and liquid injection (21) comprising at least one kneading spindle element or at least one toothed mixing element, or at least one positive transport element, or at least one negative transport element or a mixture thereof, said area extending along a length between three and seven times the diameter of the extruder; x.- subject the mixture obtained in the previous stage ¡x.-, through a third venting port (23), to venting and vacuum degassing in a third venting zone

(22) comprising spindle elements of negative or reverse transport and positive transport Ia which extends along a length between three and seven times the diameter of the extruder.

According to a preferred embodiment according to the present invention, the temperature in stage i.- is comprised between 20 and 50 ⁰ C, the temperature in stage i¡.- is comprised between 175 ⁰ C and 205 ⁰ C, the temperature in stage iii.- is between 175 ⁰ C and 205 ⁰ C, the temperature in stage iv.- is between 174 ⁰ C and 204 ⁰ C, the temperature in stage v.- is between 174 ⁰ C and 204 ⁰ C, the temperature in stage vi.- is comprised between 173 ⁰ C and 203 ⁰ C, the temperature in stage vii.- is comprised between 171 ⁰ C and 201 ⁰ C, the temperature in stage viii. - is between 171 ⁰ C and 201 ⁰ C, the temperature in stage ix.- is between 169 ⁰ C and 199 ⁰ C, the temperature in stage x.- is between 167 ⁰ C and 197 ⁰ C. Optionally, the temperature in the discharge zone (4) is comprised between 165 ⁰ C and 195 ⁰ C.

Each gravimetric dispenser used in stage i.- may have different configuration depending on the nature of the component to be fed: i. for pellet-shaped components, to be fed in said stage i.-, the gravimetric dispenser can preferably be selected from the double spindle feeders, whose spindles have a minimum external diameter of 20 mm, a minimum propeller angle of 11, 31 sexagesimal degrees, a minimum fillet thickness of 1.5 mm and a minimum channel depth of 3 mm; or between single spindle feeders whose spindle has a minimum external diameter of 24 mm, a minimum propeller angle of 7.12 sexagesimal degrees, a minimum fillet thickness of 1.5 mm and a minimum channel depth of 3 mm; ii. for powder-shaped components, to be fed in said stage i.-, the gravimetric dispenser can preferably be selected from the double spindle feeders, whose spindles have a minimum external diameter of 12 mm, a minimum propeller angle of 9, 47 sexagesimal degrees, a minimum fillet thickness of 1 mm and a minimum channel depth of 1 mm; iii. for components in the form of irregular scales or particles (such as those corresponding to residual polymers from urban solid waste), to be fed at said stage i.-, the gravimetric dispenser can preferably be selected from the double spindle feeders , whose spindles have a minimum external diameter of 35 mm, a minimum propeller angle of 19.65 sexagesimal degrees, a minimum fillet thickness of 3 mm and a minimum channel depth of 7.5 mm.

Optionally, the spindle configuration in stage d) comprises a combination of spindle elements of positive transport and toothed mixing. The configuration of the gravimetric dosers used in stages v.- and viii.- will depend on the physical characteristics of the cellulosic material and the flame retardant respectively. Preferably, the double screw gravimetric dispenser (14) used in step v.- to increase the cellulosic material can be selected from the feeders, whose spindles have a minimum external diameter of 35 mm, a minimum helix angle of 19, 65 sexagesimal degrees, a minimum fillet thickness of 3 mm and a minimum channel depth of 7.5 mm. In accordance with another preferred embodiment according to the present invention, the double screw gravimetric dispenser (20) used in step viii.- to feed the flame retardant has a minimum external diameter of 20 mm, a minimum propeller angle of 11, 31 sexagesimal degrees, a minimum fillet thickness of 1.5 mm and a minimum channel depth of 3 mm.

In accordance with a preferred embodiment according to the present invention, the two mandrels of the corroding extruder preferably rotate at a speed greater than 200 rpm and the two mandrels rotate in the same direction, in accordance with the direction of transport of the components. In this way, a good dispersion of the cellulose fibers and the rest of the components of the composite material can be achieved. In addition, said speeds of rotation of the spindles allow to achieve productions of composite material higher than those that can be achieved, using the embodiments described in the prior art. The method object of the invention allows, however, the control of the length and slenderness -relation length / diameter- of the cellulose fibers, in order to optimize the properties of the composite materials, according to the applications that are also object of this invention. During the kneading stage of the cellulosic material (stage vi.-) said cellulosic material is kneaded with the components of the composite material that have been mixed and kneaded in the previous stages. In this way, the cellulosic material is subjected to dispersive or distributive mixing, depending on the spindle elements selected, in accordance with the spindle configuration chosen to obtain the composite material. The kneading of the cellulosic fibers requires sufficient time for mixing with the molten polymer, as well as for its mechanical anchoring with it, and for reacting with the coupling agent. Thus, in the present invention, in order to avoid thermal and mechanical degradation of the cellulosic fibers, preferably stage vi.- comprises kneading by means of toothed mixing elements. This configuration allows the fibers to be distributed evenly and effectively.

Stage ix.- of flame retardant kneading; You should understand as little time as possible to prevent additives that can decompose due to shearing, such as some flame retardants, from decomposing.

The composite materials according to the present invention have characteristics that make them suitable for use in the manufacture of components for various sectors, even for moderately demanding applications, such as those in the sectors of manufacture of electrical, electronic and telecommunications equipment, being able to in this way replace different materials reinforced with fiberglass and thermosetting polymers, currently used. Among these requirements are resistance to abnormal heat and fire. Moreover, the composite materials according to the present invention respond to the growing environmental restrictions, by reusing waste materials from other industries. An important advantage is that the new composite materials have a uniform rheological behavior and a relatively low viscosity that makes them easily moldable in various articles, following different techniques such as extrusion, injection molding and compression molding, using the machinery available in the market. This advantage is inherent in the new composite materials and the method object of the present invention. This advantage means that items with wall thicknesses as thin as 0.5 mm can be molded at industrial production rates, without damaging the properties of the composite materials or the appearance of the molded articles. Therefore, in accordance with a third essential aspect, the present invention relates to the use of the composite material according to the present invention to obtain molded articles. Said articles are especially suitable for use in the electrical, electronic and telecommunications sectors, preferably for the manufacture of fuse bases, common telecommunications infrastructures and boxes for meter centralization. The articles obtained meet the requirements of stability and resistance to heat and fire required in these industries. Additionally, said articles formed from a composite material according to the present invention, are also suitable for use in the construction, aviation, automotive, furniture sectors.

Next, several preferred embodiments according to the present invention are described for a better understanding thereof, with examples that in no case are limiting.

Example 1

For the sake of clarity and brevity, in this example, only the distinctive features of the embodiment of the invention corresponding to this example are described.

From the part of the mandrel that is coupled to the drive unit of the extruder (1) to the end of the mandrel that corresponds to the head of the same (5) (from left to right in the following table), in each of the two mandrels of the corroding extruder, various spindle elements were introduced in the order indicated in Table I:

Table

Keys of the table: ETP means Positive Transport Element; EA means Kneading Element; ETN means Negative Transport Element; EMD stands for Serrated Mix Element

Both mandrels were thus configured with identical spindle configuration. Its rotation speed, in this case, was set at 300 rpm.

The temperature profile set in the different mixing stages and in the discharge zone (4) of the extruder is shown in Table II:

Il table

The polymer, the planar agglomerates of the cellulosic material from the rejections and losses of the production process of kraft pulp from Eucalyptus globulus wood, previously dried and transformed into agglomerates with the appropriate morphology for continuous feeding, the agent of coupling, the antioxidants and the flame retardant, were continuously fed to said corroding double screw extruder for mixing in molten phase. Following the method described above, a composite material was obtained which, for every 100 parts of its weight, comprised:

• 44.25 parts, by weight, of a homopolymer polypropylene with a flow rate of 75 g / 10 minutes (according to ISO 1133, at 230 ° C and 2.16 kg).

• 1.15 parts, by weight, of a polypropylene grafted with maleic anhydride with a number average molecular weight of 3900, a mass average molecular weight of 9100 and a content of maleic anhydride of 8.21% by weight. • 0.15 parts, by weight, of pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) (CAS # 6683-19-8)

• 0.62 parts, by weight, of (3, 3-Methylpropionate) dioctadecyl (CAS # 693-36-7)

• 30.77 parts, by weight, of a cellulosic material from the rejections and losses of the production process of kraft pulp from Eucalyptus globulus wood.

• 23.06 parts, by weight, of the non-halogenated flame retardant ammonium polyphosphate (CAS # 68333-79-9)

The composite material pellet of the formulation corresponding to this example, finally obtained, was fed to an injection molding machine of 450 kN of closing force, in which the cylinder or plasticizing chamber of the injection molding machine is heated according to the selected temperature profile (see table III):

Table III

The cooling time was 25 seconds. Thus, multipurpose specimens were obtained in accordance with ISO 3167 that were used to determine the properties of the composite material obtained. In accordance with ISO standards, the values of the main mechanical and thermal properties of the composite materials obtained were:

Example 2 Following the method described in Example 1 and using planar agglomerates of a cellulosic material consisting of virgin fibers of raw cellulose pulp of Eucalyptus globulus previously dried and whose morphology allowed its continuous feeding to the extruder without being subjected to the aforementioned transformation process, a composite material was obtained which, for every 100 parts of its weight, included:

• 44.25 parts by weight of a polypropylene homopolymer with a melt index of 75 g / 10 minutes (according to ISO 1133, at 230 ⁰ C and 2.16 kg).

• 1.15 parts, by weight, of a polypropylene grafted with maleic anhydride with a number average molecular weight of 3900, a mass average molecular weight of 9100 and a content of maleic anhydride of 8.21% by weight.

• 0.15 parts, by weight, of pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) (CAS # 6683-19-8)

• 0.62 parts, by weight, of (3, 3 ^x -thiodiprσpiσnato) dioctadecyl (CAS # 693-36-7)

• 30.77 parts, by weight, of a cellulosic material consisting of virgin fibers of raw cellulose pulp from Eucaliptus globulus.

Following the method described in example 1, the composite material pellet of the formulation corresponding to this example was injected to obtain multipurpose specimens in accordance with ISO 3167. According to ISO standards, the values of the main mechanical properties and The thermal materials obtained were (see table IV):

Table IV

Example 3

Following the method described in Example 1 and using planar agglomerates of a cellulosic material consisting of virgin fibers of bleached cellulose pulp from previously dried Eucalyptus globulus and whose morphology allowed its continuous feeding to the extruder without being subjected to the process of The above-mentioned transformation obtained a composite material that, for every 100 parts of its weight, comprised:

• 44.25 parts by weight of a polypropylene homopolymer with a melt index of 75 g / 10 minutes (according to ISO 1133, at 230 ⁰ C and 2.16 kg). • 1.15 parts, by weight, of a polypropylene grafted with maleic anhydride with a number average molecular weight of 3900, a mass average molecular weight of 9100 and a content of maleic anhydride of 8.21% by weight.

• 0.15 parts, by weight, of tetrakis (3- (3,5-dT-tert-butr-4-hydroxyphenyl) propyonate) of pentaerythritol (CAS # 6683-19-8) • 0.62 parts, by weight of dioctadecyl (3, 3-propionate) diodedecyl (CAS # 693-36-7)

• 30.77 parts, by weight, of a cellulosic material consisting of virgin fibers of bleached cellulose pulp from Eucaliptus globulus.

• 23.06 parts, by weight, of the non-halogenated flame retardant ammonium polyphosphate (CAS # 68333-79-9) Following the method described in example 1, the composite material pellet of the formulation corresponding to this example was injected to obtain specimens multipurpose in accordance with ISO 3167. According to ISO standards, the values of the main mechanical and thermal properties of the composite materials obtained were (see table V):

Table V

Example 4

Following the method described in example 1 and using planar agglomerates of a cellulosic material constituted by residual cellulose fibers of a recycled paper process used previously dried and transformed into agglomerates with the morphology suitable for continuous feeding, a composite material was obtained which, for every 100 parts of its weight, included:

• 0.62 parts, by weight, of (3, 3 ^x -iodiopropionate) dioctadecyl (CAS # 693-36-7) • 30.77 parts, by weight, of a cellulosic material consisting of residual cellulose fibers of a cellulose waste paper recycling process

Following the method described in example 1, the composite material pellet of the formulation corresponding to this example was injected to obtain multipurpose specimens in accordance with ISO 3167. According to ISO standards, the values of the main mechanical properties and The thermal materials obtained were (see Table Vl):

Vl table

Example 5

Using the composite material with the composition described in Example 1 and the method described in said example, pellets were produced in sufficient quantity to feed an industrial injection molding machine of 2000 kN of closing force, in which the cylinder or Plasticizing chamber of the injection molding machine was heated according to the following selected temperature profile (see Table VII):

Table VII

ZONES OF THE CYLINDER OF THE ZONE 1 ZONE 2 ZONE 3 ZONE 4 INJECTOR NOZZLE

Temperature ( ⁰ C) 180 185 195 200 200

B cooling time was 30 seconds. In this way, the fuse holder base for blade fuses was shown, which is shown in Figure 3, characterized by a minimum wall thickness of 2.66 mm and for whose injection the maximum melt flow path was 20 cm, approximately. This product underwent various tests set by the standards that apply to these types of products. Table VIII shows the results of said tests, as well as their comparison with the results obtained for the same product manufactured with a conventional material such as poly (butylene glycol terephthalate) (PBTP) reinforced with 30% fiberglass.

Table VIII

Example 6

Using the composite material with the composition described in Example 1 and the method described in said example, pellets were produced in sufficient quantity to feed an industrial injection molding machine of 800 kN closing force, in which the cylinder or Plasticizing chamber of the injection molding machine was heated according to the temperature profile, selected as follows (see table IX):.

Table IX

The cooling time was 12 seconds. In this way, the body and the handle of the fuse holder base for cylindrical fuses are shown, which is shown in Figure 4, characterized by a minimum wall thickness of 2 mm and for whose injection the maximum melt flow path was 25 cm, approximately. This product underwent various tests set by the standards that apply to these types of products. Table X shows the results of said tests, as well as their comparison with the results obtained for the same product manufactured with a conventional material such as poly (butylene glycol terephthalate) (PBTP) reinforced with 30% fiberglass. Table X

Example 7

Using the composite material with the composition described in Example 1 and the method described in said example, pellets were produced in sufficient quantity to feed an industrial injection molding machine of 800 kN closing force, in which the cylinder or Plasticizing chamber of the injection molding machine was heated according to the following selected temperature profile (see table Xl):

Table Xl

ZONES OF THE CYLINDER OF THE ZONE 1 ZONE 2 ZONE 3 ZONE 4 INJECTOR NOZZLE

Temperature ( ⁰ C) 180 185 195 200 200

The cooling time was 8 seconds. Thus, the body and the handle of a fuse holder base for cylindrical fuses were manufactured similar to that shown in Figure 4, characterized by a minimum wall thickness of 1.74 mm and for whose Injection, the maximum melt flow path was approximately 20 cm. This product underwent various tests set by the standards that apply to these types of products. Table XII shows the results of said tests, as well as their comparison with the results obtained for the same product manufactured with a conventional material such as poly (butylene glycol terephthalate) (PBTP) reinforced with 30% fiberglass.

Table XII

Example 8

Using the composite material with the composition described in Example 1 and the method described in said example, pellets were produced in sufficient quantity to feed an industrial injection molding machine of 5000 kN of closing force, in which the cylinder or Plasticizing chamber of the injection molding machine was heated according to the following selected temperature profile (see table XIII): Table XIII

ZONES OF THE CYLINDER OF THE ZONE 1 ZONE 2 ZONE 3 ZONE 4 INJECTOR NOZZLE

Temperature ( ⁰ C) 180 185 195 200 200

The cooling time was 60 seconds. In this way, a part of the body of the closed three-pole vertical bases was shown, which is shown in Figure 5, characterized by a minimum wall thickness of 1.66 mm and for whose injection the maximum melt flow path was 48 cm, approximately. This product underwent various tests set by the standards that apply to these types of products. Table XIV shows the results of said tests, as well as their comparison with the results obtained for the same product manufactured with a conventional material such as pqljarηida. reinforced with 20% fiberglass.

Table XIV

Example 9

In this example (see table XV) some of the results of the tests carried out for the determination of the most appropriate set of dosers are shown depending on the component to be fed:

Table XV

Keys of the table: D _ext means external diameter of each spindle; α means the propeller angle of each spindle; Esp. Means thickness of the fillets of each spindle; Prof. means Channel depth of the channels of each spindle; D _hEmb means external diameter of the spindles of the stuffer.

Claims

Claims:

1. Composite material which, for every 100 parts of its weight, comprises: (A) between 25 and 90 parts, by weight, of a thermoplastic polymer; (B) between 1 and 50 parts, by weight, of a cellulosic material, (C) between 0.1 and 15 parts, by weight, of a coupling agent; (D) between 0.05 and 3 parts, by weight, of a primary antioxidant; (E) between 0.05 and 6 parts, by weight, of a secondary antioxidant (F) between 1 and 40 parts, by weight, of a flame retardant, characterized in that said cellulosic material (B) comprises fibers that are selected from the group formed by virgin cellulose pulp fibers from hardwood tree species, fibers obtained as waste from the pulp and paper industry, fibers obtained as waste from the synthetic and textile fiber manufacturing industries, fibers from solid urban and industrial waste or mixtures thereof.

2. Composite material according to claim 1, characterized in that said virgin cellulose pulp fibers from hardwood tree species; they can be virgin fibers, either raw, bleached or refined.

3. Composite material according to claim 1, characterized in that said fibers obtained as waste from the pulp and paper industry are the residual pulp fibers of the pulp production processes from wood species , from the rejections of the sieving processes of the mixture of cellulose fibers and black liquor that leaves the digesters, of the final rejections of the processes of purification of the cellulose pulp, and of various losses and leaks through the fabrics of the scrubbers used in the different phases of the bleaching of the cellulose pulp and through the sheet-forming fabric in the window dressing machine, said residual fibers being presented in the form of planar agglomerates of irregular shape and contour, whose diameter equivalent to their projected area is essentially less than 67 mm, whose sphericity is between 0.5 and 0.9, and whose roundness is comprised in Between 0.3 and 0.7, with an apparent density between 0.08 and 0.380 g / cm ³ , said agglomerates comprising, on a dry basis, between 5 and 20%, by weight, of ashes, between 5 and 20%, by weight, of lignin and between 55 and 90%, by weight, of holocellulose.

4. Composite material according to claim 1, characterized in that said fibers obtained as waste from the pulp and paper industry are the residual cellulose fibers from the industrial processes of manufacturing cellulose pulp from selected plant plants from the group that includes jute, abaca, sisal, hemp, flax, or mixtures thereof.

5. Composite material according to claim 1, characterized in that said fibers obtained as waste from the synthetic and textile fiber manufacturing industries are selected from the group consisting of cellulose fibers from the rejections of the synthetic fiber manufacturing processes, fibers of Cellulose obtained from the recycling of spent textile products, or residual cellulose fibers from industrial manufacturing processes of non-woven fabrics.

6. Composite material according to claim 1, characterized in that said fibers from urban and industrial solid waste are waste or cellulose fibers from the urban solid waste stream or residual cellulose fibers of the paper and cardboard recycling processes used.

7. Composite material according to any of the preceding claims, characterized in that said cellulosic material (B) comprises cellulosic fibers with individual lengths between 0.1-10 mm, individual fiber diameters between 0.01-50 μm, and length ratios / diameter individual between 2-250.

8. Composite material according to any of the preceding claims, characterized in that said coupling agent (C) is selected from the group consisting of polyolefins grafted with maleic anhydride, said polyolefins having number average molecular weights between 2000 and 50,000 or average molecular weights in mass between 4000 and 300000, and having contents of maleic anhydride between 0.1 and 20%, by weight; pure or modified polyethyleneimines whose molecular weights vary between 800 g / mol and 200000 g / mol-g, which are presented as anhydrous products or not; aromatic and aliphatic organosilanes or mixtures thereof. 9. Composite material according to any of the preceding claims, characterized in that said primary antioxidant (D) is selected from the group consisting of sterically hindered phenols with a molecular weight greater than 300g / mol, cinnamates, amines or mixtures thereof.

10. Composite material according to any of the preceding claims, characterized in that said flame retardant (F) is selected from the group consisting of compounds belonging to the category of phosphorus compounds, chlorinated compounds, brominated compounds or mixtures thereof. 11. Composite material according to any of the preceding claims, characterized in that it additionally comprises one or more of the following synergistic compounds with respect to the flame retardant (F): aluminum trihydroxide, hydrated aluminas, borates, stannates, magnesium hydroxide, antimony oxide (III) and compounds that belong to the category of nitrogen-containing compounds. 12. Composite material according to any of the preceding claims, characterized in that said secondary antioxidant (E) is selected from the group consisting of phosphorus compounds, thioethers, thioesters, preferably thioethers, or mixtures thereof.

13. Composite material according to any of the preceding claims, characterized in that it comprises at least one lactone.

14. Composite material according to any of the preceding claims, characterized in that it additionally comprises between 0.1 and 40%, by weight, with respect to the total weight of the composite material, of an additive (G) selected from the group formed by the stabilizers to light or UV stabilizers, modifiers of impact properties, inorganic fillers, lubricants, pigments, biocides and foaming agents or mixtures thereof.

15. Composite material according to any of the preceding claims, characterized in that said thermoplastic polymer (A) is selected from the group consisting of polypropylene homopolymers, propylene copolymers, polypropylene-vinyl acetate polypropylene, high density polyethylene, low density polyethylene, a polystyrene, preferably which is selected from the group of its homopolymers, copolymers or terpolymers, polyvinylchloride, a polymer from the group of polyamides, poly (ethylene glycol terephthalate), poly (butylene glycol terephthalate ), poly (methyl methacrylate), polycarbonate or mixtures thereof. 16. Composite material according to claim 15, characterized in that said polypropylene homopolymer or copolymer is selected from polypropylene homopolymers and copolymers of rheology controlled with points of Similar fusion and melt indices ranging from 12 to 150 g / 10 minutes (according to ISO 1133 at 230 ⁰ C and 2.16 kg).

17. Composite material according to any of the preceding claims, characterized in that said thermoplastic polymer (A) comprises thermoplastics present in urban solid waste or in industrial waste from the transformation of plastics.

18. A method for the continuous production of a composite material according to claims 1 to 17, characterized in that it comprises the following steps: a) drying said cellulosic material; b) be provided with a corroding double spindle extruder, which comprises two mandrels (3), in each of which an identical spindle configuration is mounted using different spindle elements being the relationship between external and internal diameter of said elements of spindle, between 1, 02 and 2; c) mix the components of the composite material; and d) discharge the resulting composite material through a discharge zone (4)

Which extends along a length between three and seven times the diameter of the extruder.

19. Method according to claim 18, characterized in that before stage b), it comprises an additional stage of transformation of the cellulosic materials into planar agglomerates of irregular shape and contour, whose diameter equivalent to their projected area is essentially less than 15 mm , whose sphericity is between 0.3 and 0.7, and whose roundness is between 0.1 and 0.7, suitable for continuous feeding.

20. Method according to claim 19, characterized in that said cellulosic material is dried to reach a moisture content comprised between 1 and 10%, by weight.

21. Method according to any of claims 18-20, characterized in that the two mandrels of the corrotant extruder rotate at a speed greater than 200 rpm.

22. Method according to any of claims 18-21, characterized in that the mixing stage c) comprises the following steps: i.- dosing through a feed hopper (6) the thermoplastic polymer (A), the coupling agent (C), the primary antioxidant (D) and the secondary antioxidant (E) and optionally also the additives (G) that are selected from the group consisting of light stabilizers or UV stabilizers, modifiers of impact properties, inorganic fillers, lubricants, pigments, biocides and foaming agents, by means of a set of gravimetric dosers (2), within a polymer feeding zone and additives (7), which comprises positive transport spindle elements and extends along a length between three and seven times the diameter of the extruder; ii.- heating the mixture obtained in step i.- and transporting said mixture along a closed transport and heating zone (8) comprising positive transport spindle elements; iii.- melting, mixing and kneading said mixture in a melting zone (9), comprising kneading spindle elements, the joint length of the closed transport and heating zone (8) and the melting zone being comprised ( 9) between three and seven times the diameter of the extruder; - iv.- subjecting the previous mixture, through the atmospheric venting port (11), to venting and degassing in a first venting zone (10) comprising spindle elements of negative or reverse transport and positive transport; v.- continuously dosing the cellulosic material (B) in a lateral feeding zone of the cellulosic material (12) comprising positive transport spindle elements, using a first double spindle stuffing with spindles that must have a minimum external diameter 24 mm (13), in turn fed by a second double screw gravimetric dispenser (14) disposed above said first stuffer, the joint length of the first vent zone (10) and the lateral feed zone being comprised of the cellulosic material (12) between three and eight times the diameter of the extruder. vi.- kneading the mixture obtained in the previous stage v.- in an area of incorporation of the cellulosic material and liquid injection (15) comprising at least one kneading spindle element or at least one toothed mixing element, or at less a positive transport element, or at least one negative transport element or a mixture thereof, said area extending along a length between three and seven times the diameter of the extruder; vü -submit the mixture obtained in the previous stage vi.- through a second atmospheric venting port (17), to venting and degassing in a second zone of venting (16) comprising transport and positive transport spindle elements; viii.- continuously dosing a flame retardant (F) in a side feed zone of the flame retardant (18) comprising positive transport spindle elements using a second double spindle stuffing chamber with chamber and preferably chilled spindles (19) said spindles having a minimum external diameter of 20 mm, fed in turn by a third double spindle gravimetric dispenser (20) disposed above said second stuffer

(19), the joint length of the second venting zone (16) and the lateral feed zone of the flame retardant (18) being comprised between three and eight times the diameter of the extruder. ix.- kneading the mixture obtained in the previous stage viii.- in an area of incorporation of the d & Hama retarder and liquid injection (21) comprising at least one kneading spindle element or at least one toothed mixing element, or at least one positive transport element, or at least one negative transport element or a mixture thereof, said area extending along a length between three and seven times the diameter of the extruder; x.- subject the mixture obtained in the previous stage ix.-, through a third venting port (23), to venting and vacuum degassing in a third venting zone (22) comprising negative transport spindle elements or inverse and positive transport Ia which extends along a length between three and seven times the diameter of the extruder.

23. Method according to claim 22, characterized in that each gravimetric dispenser of those used in stage i.- can have different configuration depending on the nature of the component to be fed: i. For pellet-shaped components, to be fed in said stage i.-, the gravimetric dispenser can preferably be selected from the double spindle feeders, whose spindles have a minimum external diameter of 20 mm, a minimum propeller angle of 11, 31 sexagesimal degrees, a minimum fillet thickness of 1.5 mm and a minimum channel depth of 3 mm; or between single spindle feeders whose spindle has a minimum external diameter of 24 mm, a minimum propeller angle of 7.12 sexagesimal degrees, a minimum fillet thickness of 1.5 mm and a minimum channel depth of 3 mm; ii. for powder-shaped components, to be fed in said stage i.-, the gravimetric dispenser can preferably be selected from the double spindle feeders, whose spindles have a minimum external diameter of 12 mm, a minimum propeller angle of 9, 47 sexagesimal degrees, a minimum fillet thickness of 1 mm and a minimum channel depth of 1 mm; iii. for components in the form of irregular scales or particles (such as those corresponding to residual polymers from urban solid waste), to be fed at said stage L-, the gravimetric doser can preferably be selected from among the double screw feeders, whose spindles have a minimum external diameter of 35 mm, a minimum propeller angle of 19.65 sexagesimal degrees, a minimum fillet thickness of 3 mm and a minimum channel depth of 7.5 mm.

24. Method according to any one of claims 18-23, characterized in that the spindle configuration in stage d) comprises a combination of spindle elements of positive transport and toothed mixing.

25. Method according to claim 22, characterized in that the double-spindle gravimetric dispenser (14) used in step v. * To feed the cellulosic material can be selected from the feeders, whose spindles have a minimum external diameter of 35 mm, a minimum propeller angle of 19.65 sexagesimal degrees, a minimum fillet thickness of 3 mm and a minimum channel depth of 7.5 mm.

26. Method according to claim 22, characterized in that the double-spindle gravimetric dispenser (20) used in step viii.- to feed the flame retardant has a minimum external diameter of 20 mm, a minimum propeller angle of 11, 31 sexagesimal degrees, a minimum fillet thickness of 1.5 mm and a minimum channel depth of 3 mm.

27. Method according to any of claims 22-26, characterized in that the temperature in stage L- is comprised between 20 and 50 ⁰ C, the temperature in stage ii.- is comprised between 175 ⁰ C and 205 ⁰ C, Ia temperature in stage iii.- is between 175 ⁰ C and 205 ⁰ C, the temperature in stage iv.- is between 174 ⁰ C and 204 ⁰ C, the temperature in stage v.- is between 174 ° C and 204 ⁰ C, the temperature in stage vi.- is between 173 ⁰ C and 203 ⁰ C, the temperature in stage viL is between 171 ⁰ C and 201 ⁰ C, the temperature in stage viü.- it is comprised between 171 ⁰ C and 201 ⁰ C, the temperature in stage ¡x.- is comprised between 169 ⁰ C and 199 ⁰ C, the temperature in stage x.- is between 167 ° C and 197 ⁰ C.

28. Method according to any of claims 18-27, characterized in that the temperature in the discharge zone (4) is comprised between 165 ⁰ C and 195 ⁰ C.

29. Method according to any of claims 18-28, characterized in that the composite material, after passing through the discharge zone (4) and being subjected to a granulation process, is subjected to an injection molding process.

30. Method according to claim 29, characterized in that said injection molding process comprises injecting the granulated composite material at a temperature less than 210 ⁰ C in any of the heating zones of a chamber or piastification cylinder of a molding machine by injection. 3-1. A method according to any of claims 18-28, characterized in that the composite material is subjected to a direct extrusion process after passing through the discharge zone (4).

32. Method according to any of claims 18-28, characterized in that said composite material is subjected to a calendering process as it leaves the discharge zone (4) in order to obtain a thin panel, followed by compression molding . 33. Use of a composite material according to claims 1-17 to obtain molded articles.

34. Use according to claim 33 for obtaining molded articles suitable for the electrical, electronic and telecommunications sector.

35. Use according to claim 34 for obtaining fuse bases. 36. Use according to claim 34 for obtaining boxes for common telecommunications infrastructure.

37. Use according to claim 34 for obtaining boxes for centralization of meters.

38. Use according to claim 33 for obtaining molded articles in the construction, aviation, automotive, furniture and packaging sectors.