WO2015004074A1

WO2015004074A1 - Spunbonded nonwovens and threads made of lignin-containing fiber-forming polymers and a method for the production thereof

Info

Publication number: WO2015004074A1
Application number: PCT/EP2014/064483
Authority: WO
Inventors: Lüder GERKING
Original assignee: Gerking Lüder
Priority date: 2013-07-08
Filing date: 2014-07-07
Publication date: 2015-01-15
Also published as: EP3019647A1; EP2824224A1

Abstract

The invention relates to spunbonded nonwovens and yarns made of fiber-forming polymers that can be produced from a spinning material that contains fiber-forming polymers, wherein the spinning material is spun from at least one spinning hole and the spun thread is drawn by gas streams that are continuously accelerated to a high speed by means of a de Laval nozzle, characterized in that the spinning material contains lignin as an additive.

Description

Spinnyliese and filaments of lignocellulosic fiber-forming polymers and process for its preparation

The invention relates to spunbonded nonwovens or yarns produced from spinning solutions or melts according to the nanovalue splicing spinning process, to which lignin is added before spinning. The spinning solutions, preferably in

Amine oxides of dissolved cellulose, or the melts, preferably of synthetic fiber-forming polymers are spun from at least one spinning bore and the spun yarn is spliced by means of a Laval nozzle to high speed steadily accelerated gas streams into finer threads and warped with loop and loop formation, the gas flow is substantially laminar in the field of thread formation. The invention further relates to processes for producing such spunbonded nonwovens and yarns from the fibers or filaments.

This spinning process, called splicing spinning process for short, is described in EP 1 192 301 Bl for melt-spun threads and nonwovens thereof and in US Pat EP 1 358 369 B1 for solution-spun threads and nonwovens thereof.

In the state of the art, the production of cellulose fibers is known. Thus, EP 1 379 713 Bl describes a process for the preparation of

Cellulose fibers or elements of pulp after a dry-wet extrusion process with aqueous amine oxides, today also referred to as lyocell threads. However, it has been shown that such methods do not have sufficient spinning safety. The disadvantage is in particular that undissolved particles or unevenly enriched with cellulose masses lead to thread breaks. Furthermore, from EP 1 358 369 Bl a method has become known in which threads of spun from spinneret solutions of fiber-forming dope are deformed by warping and splicing in endless or finite long threads by splicing or even bursting and warping into much finer threads than that Ausgangsmonofil. This splice spinning process is in contrast to all other known spinning processes of melts or solutions. In other spinning processes, the longitudinal distortion is effected either by mechanical tensile forces by means of winders or other devices which generate the forward movement of the yarn, or by accompanying gas streams, generally air streams, as in the spunbonding processes.

In the splicing spinning process, now also often referred to as nanoval process, splicing occurs up to the sudden bursting of the liquid thread monofilament, in that the accompanying accelerated gas flow, whose velocity is higher than the velocity of the monofilament, generates shear stresses on the monofilament. The gas flow is preferably substantially laminar in the area of the thread formation. Due to a special fluidic effect, forces are generated in the liquid thread as a result of the action of the outer gas flow, so that parts of the monofilament splinter off or burst open altogether. The spun threads are cooled by the gas / air flow from the outside or by withdrawal Volatiles outside solid, so that forms a pipe structure. It essentially comes to endless threads in this particular process.

Characteristics are always spinnerets spun out of the yarn mass and the accelerated gas flow surrounding the yarn, often in the form of Laval nozzles or in their modification of shaped channels in the flow direction behind the spinnerets.

Since several threads are formed in this process from an opening for the fiber stream to be spun, the spinning openings can be larger than in comparison to other spinning methods, and yet fine threads can be produced, which is otherwise possible with linear distortion only with lower throughput. Solid, unmelted or dissolved additives of the thread mass can be added without the risk of clogging in the spinning bores.

Due to the accompanying gas flow, here air flow, it comes after a thread break for the automatic Wiederanspinnen. This is in contrast to all known Cellulosespinnverfahren, whether from the spinneret via an air gap and then by a precipitation bath as in dry-wet lyocell spinning or the viscose spinning process with the spinneret directly in the precipitation bath, a significant advantage of splice spinning, and in particular if the spinning masses are not homogeneous, but contain other substances as additives. The same applies to the spinning of synthetic polymers.

However, it has been shown that the processes of the prior art, when fibers are to be processed into spunbonded fabrics, are complicated and cost-intensive.

On this basis, it is the object of the present invention to provide novel spunbonded nonwovens or yarns which can be produced simply and inexpensively from fibers and filaments of fiber-forming polymers and to provide a corresponding process. The invention is achieved with respect to the method by the features of claim 1 and with respect to the spunbonded nonwoven by the features of claim 11. The present invention (claim 1) is the admixture of

Lignin as an additive to the dope of fiber-forming polymers, which causes special properties of the threads produced later in yarns or nonwovens. The matrix consists of cellulosic fibers and threads for nonwovens and

Yarns of cellulose, also commonly called pulp, spun from solutions in NMMO (N-methylmorpholine-N-oxide); but it can also be used as other ionic solvents or other organic origin. Thus, the spinning solutions for viscose filaments (rayon) can also be used. The spunbonded nonwovens or yarns according to the invention are produced by the splicing spinning process (nanoval process), the accompanying air streams depositing the filaments into a nonwoven fabric with the special properties added by lignin compared to the pure spinning composition of the fiber-forming polymers. The threads can also be collected into yarns below the splicing device, each consisting of spinning and gas (Laval) nozzle.

The same applies to the embodiment of the invention when not working with a spinning solution but with melting of fiber-forming polymers.

If lignin is introduced into the spinning dope, ie either into the spinning solution or into the melt prior to spinning, then a binder is present in the nonwoven. The same is true when creating yarns. In the nonwovens, in the case of added lignin, the binding of the threads to one another is produced by pressure and temperature effects on the produced nonwoven. It can therefore be omitted that additional binders are later added to the fleece or that binding threads are spun with, spun from separate spinning systems or as bicomponents such as core / sheath threads of special spinning units of two fibers, the sheath of which has a lower softening temperature than the inside of the thread, the matrix, has. chemical see binder or mechanical needling of the nonwoven fabrics are generally no longer required for pure nonwoven weave. According to the invention, the spinning masses are thus loaded with lignin. Similar to wood, the fleece is made by lignin a forces-absorbing dressing.

The fiber-forming polymer used according to the invention is preferably cellulose. In the case of cellulose as a fiber-forming polymer, it has been possible to show that, instead of the expensive chemical pulp (mainly alpha-cellulose) required for cellulosic viscose / rayon threads, it is also possible to spin paper pulp with high levels of hemicellulose. It has also been shown that paper, for example waste paper, can be added to a cellulose NMMO solution or even make this spinning solution 100% from waste paper and in which highly resistant to contamination splicing can produce nonwovens, again with fine monofilaments larger than in the other methods necessary narrower spin holes. With regard to the embodiment of the method, reference is made to EP 1 358 369 B1.

The solvent used for cellulose fibers is preferably NMMO or ionic solvents. An ionic solvent is a salt in which the ions are so poorly coordinated that the solvents are liquids below 100 ° C or even liquid at room temperatures. This requires delocalized charges and at least one ion based on an organic molecule to prevent the formation of a stable crystal lattice. Methylimidazolium and pyrithinium ions have proven to be good

Starting points for the development of ionic liquids proved. . Examples include, EMIMac, BMIMac, EMIMCI, BMIMCI, EDMIMCI, BDMIMCI, EMIMTfO ^"BMIMBF _four, BMIMNTf With regard to the nomenclature referred z.um instance to: URL: http: //www.organische- chemistry ch / OC. In accordance with the invention, 3-20%, more preferably 4-15% of lignin, based on the fiber-forming polymer, is used, and 5-20% of fiber-forming polymers have proven favorable in the spinning solution preferably 5-15%, particularly preferably 8-13% of fiber-forming polymers are contained.

For spunbonded nonwovens or yarns (claim 11), which consist of the melt of fibrous In principle, all fiber-forming polymers such as polyethylene (PE), polyethylene terephthalate (PET), polyamides (PA), polyolefins such as polypropylene (PP) can be used. With regard to the production of fibers from melts, reference is made to EP 1 192 301 Bl. The proportions of lignin in the dope are identical to the process from the solution and are 3-20%, preferably 4-15% based on the fiber-forming polymers.

In the spunbonded nonwovens or yarns according to the invention, it is particularly preferred if they contain ground wood or wood dust. Polypropylene is preferred in the fiber-forming polymers.

With regard to the spunbonded nonwovens or yarns, reference should be made in relation to the material selection to the process described above and the educts mentioned therein.

It has been shown that with such, possibly slightly modified spinning masses with appropriate process management of the splicing spinning process can finally produce long fibers in the product, the spunbonded, which is suitable to be dissolved in water flows, which is desired, for example as wipes continue with the wastewater without it in the piping systems as usual to blockages. Normally, after the splicing spinning process, predominantly to exclusively endless filaments of, for example, cellulose and the hemicelluloses are formed, which is attributed to the strong effect of the hydrogen bonds in the lyocell solution.

Other additives besides lignin may also be added to the dope. The additives are, in particular, activated carbon, superabsorbents, ion exchange resins, PCM, metals and metal oxides, flame retardants, abrasives, zeolites, phyllosilicates, such as concreteites, or modified phyllosilicates, cosmetics or Mixtures thereof. As protection against X-rays, barium sulfate, also lead in powder form can serve. Even liquid lipophilic substances, such as paraffins, waxes or oils, one or more component (s) can be introduced in lower concentrations, for example nanosilver or dyes or else active substances, for example pharmaceuticals Substances or insecticides. The additives are to be added to the spinning solutions and melts, in each case in particle sizes smaller than the opening width of the spinnerets. Further examples can be found in WO 2012/034679 AI.

When using paper as a strong additive, ie an additive with a high proportion in the spinning solution or even exclusively, it is particularly well to produce liquid streams dissolving nonwovens and thus comply with the requirement for flushability (English, flushability). This works particularly well with waste paper.

The invention will be explained in more detail by the following examples.

(All the following% values are always% by weight)

A lyocell spinning solution was prepared, with NMMO as the solvent, 11% cotton linter pulp, the cotton seed hairs, with a DP = 465 average degree of polymerisation. To the solution was added 1.0% lignin in the form of lignosulphonate from the company

Borregaard was added and fed under pressure to a single nozzle opening of 0.8 mm diameter, the emerging solution thread was caused to splice by an air flow, which was supplied to the splicing device below 1800 mbar. The throughput was 2.4 g / min. There were threads between 3.1 and 9.5 μιη diameter, on average 5.3 μιη. The amount of air was 13.7 m ³ / h. If this amount of blown air was reduced to 10 m ³ / h by lowering the feed pressure to 1000 mbar, the result was, at the same spinning throughput of 2.4 g / min, between 3.7 and 14.4 μιη, on average 7.7 μιη.

For comparison, a lyocell spinning solution was prepared without lignin and spun at 800 mbar air pressure at 2.4 g / min per spinning hole, and there were by splicing the monofilament threads between 1.7 and 3.5 μιη, so much finer, which showed in that the lignin produces a higher viscosity of the spinning solution and reduces splicing and longitudinal distortion. The threads were endless (see Table 1, experiment lh). Further experiments with different conditions of throughput

Cellulose spinning solution with lignin by addition of lignosulphonate and

different blowing air pressures are given in Table 1 below.

Table 1: Lyocell with lignin as lignosulfonate

Trial lignin lignin / cellulose throughput process air thread count

Cellulose g / min m ³ / h mbar dmin dso dmax

(μηι (μηι) (μηι))

Cotton linters

DP 465

la) 1.00% 9.1% 11% 2.4 13.7 1800 3.1 5.3 9.5 lb) 1.00% 9.1% 11% 2.4 10 1000 3.7 7, 7 14.4 lc) 1.00% 9.1% 11% 1.6 14 4000 0.9 2.6 5.4 ld) 1.50% 13.6% 11% 2.4 10 1000 3.4 8.1 12.4 le) 0.50% 4.5% 11% 2.4 10 1000 2.8 4.4 6.4 lf) 0.50% 4.5% 11% 5.1 7.5 600 2.1 3.1 5.4 lh) 0% 0.0% 11% 2.4 8.9 800 1.7 2.5 3.5

The spun splices were collected on a sieve belt so that small fleece patterns could be made from the one spinning hole. In contrast to those spun from cotton linters without lignin they were characterized by a higher cohesion, but were also a bit harder to handle. Similarly, viscose solution (rayon) was mixed with 9-10% cellulose with 1% lignosulphonate from Borregaard. Table 2: Viscose (rayon) with lignin as lignosulfonate

Experiment Cellulose Throughput Process air Filament denier dmin dso dmax Type Mo eg / min m ³ / h mbar (pm) (pm) (pm)

Lignin viscose

2 a) 1.0% 9-10% 4 5.4 300 1.6 4.6 8.2

2 b) 1.0% 9-10% 5.6 4.3 250 3 10.8 21.7

2 c) 1.0% 9-10% 5 7.5 600 2.1 7.2 17.0

The binding of the threads to a nonwoven fabric was comparable to the lyocell fleece with lignin. The values are given in Table 2.

It could also be shown that directly with the lignin of the wood, a spinning solution could be produced on the basis of otherwise taken pulp for solution-spun threads. For this purpose, wood sanding dust with a particle size of less than 130 μm of a lyocell

6% cellulosic content cellulose pulp solution added in an amount of 25% based on the originally used cellulose of 6% in the solution, d. H. in the spinning solution were then 6% cellulose and 1.5% wood. After estimating the lignin content of the wood with about 20%, this gave a lignin content in the spinning solution of 20% × 1.5% = 0.3% lignin and in the finished nonwoven a fraction of 0.3 / (6 + 1.5) 0.3 / 7.5 = 0.04 = 4%.

The spinning to splice threads of the wood and chemical pulp containing solution required some changes in the spinning parameters, because in particular the spinning solution with wood is more viscous. However, it has been shown that "wood spinning" is possible, which can be used to produce self-bonding cellulosic spunbonded webs (here lyocell), as well as to save one part of pulp, namely the one from wood to the spinning solution In the examples, about 20% of the fleece comes from the added wood, so to speak, bypassing pulp production. Table 3 shows the results of the filaments spun from "wood cellulose" in the splice spinning process: Table 3: Lyocell with chemical pulp (Modo) and wood flour

Trial wood lignin / cell cellulose throughput process air thread denier dmin d50 dmax

20% g / min m ³ / h mbar (μηΐ) (μηΐ) (μηΐ) lignin content

in the wood

Wood-chemical pulp

Share DP 650

3 a) 1.5% 5.0% 6% 4 7.5 600 12 43 104

3 b) 1.5% 5.0% 6% 6 7.9 650 8 36 105

3 c) 1.5% 5.0% 6% 8 7.9 650 9 35 107

3 d) 1.5% 5.0% 6% 1.8 8.9 800 10 30 77

3 e) 1.5% 5.0% 6% 2 8.9 800 6 34 93

In the case of the splicing spinning process according to Nanoval, the spinning solution can be produced both from chemical pulp and paper pulp, but also "stretched" by paper, also lignin-containing papers, eg K-liners with about 3% lignin, or wood In the case of yarns, this is generally not important, since the binding takes place force-fittingly by twisting all the way to twisting.

Depending on the lignin content, the spunbonded webs were soft to about 0.5% lignin and harder, stiffer above where high strengths and flexural stiffnesses occurred over 1.5%. The latter products could be used, for example, as the outer skin of automobiles with the advantage of low weight compared to steel and even aluminum. The essentially endless threads act as a reinforcement, ie a reinforcement of the surface structure of these "cellulosic sheets." Since the lignin-spun spunbonded nonwovens are deposited wet, this can take place in molds and can thus be applied later. NEN of such a band of successive shaped nonwoven bodies, the individual construction elements are made of cellulosic nonwoven. Experiments have also been conducted with polypropylene (PP) and polylactide

(PLA), which were also treated with lignosulfonate Borregaard, see Table 4 and 5.

Table 4: Polylactide (PLA) with lignin as lignosulfonate

Test lignin sulphonate polylactide throughput process air thread denier dmin dso dmax

(Borretan 103) g / min m ³ / h mbar (μηι) (μηι) (μι-η)

Lignin polylactide

0.0% 100% 1 7.1 550 0.4 1 2.4

4 a) 5.0% 95% 0.2 3.6 200 3 4.4 7

4 b) 5.0% 95% 0.4 3.6 200 1.7 2.5 3.7

Table 5: Polypropylene (PP) with lignin as lignosulfonate

The fleeces were also characterized by the fact that they could be glued by short thermal treatment of about 30 - 60 seconds using an iron with other nonwovens, cardboard or papers easily. In addition, some lignin-containing nonwovens, in particular PP nonwovens, were not so thermally sensitive. For example, two strips of once-splice-spun PP and then lignin-containing, spun-spun PP were simultaneously ironed for about 1-2 minutes at a higher but not the highest heat setting of an iron between two boards on an aluminum plate, melting the pure PP and only fusing the lignin-containing one Structure, retained its filaments.

Claims

claims

1. A process for producing a spunbonded fabric in which a spinning dope containing fiber-forming polymers and lignin additive is spun from at least one spinning bore and the spun yarn is spliced and distorted by means of a Laval nozzle to high speed steadily accelerated gas streams and the resulting filaments as a nonwoven are deposited, the dope contains 3-20% lignin, based on the fiber-forming polymers.

2. The method according to claim 1, characterized in that the gas flow in the region of the thread formation is substantially laminar

3. The method according to claim 1 or 2, characterized in that the lignin is added in the form of wood pulp of the dope.

4. The method according to at least one of claims 1- 3, characterized in that the lignin is added in the form of ground wood or wood abrasive dust of the dope.

5. The method according to at least one of claims 1- 4, characterized in that the lignin is added in the form of a lignin salt, preferably as lignosulfonate of the dope.

6. The method according to at least one of claims 1-6, characterized in that the fiber-forming polymer is selected from cel lulose, polypropylene (PP) and polylactide (PLA).

7. Process or yarn according to claim 6, characterized in that a spinning solution of cellulose dissolved in aqueous amine oxide and / or ionic solvent is used as the spinning mass.

8. The method according to claim 7, characterized in that the cellulose is obtained from chemical pulp such as alpha cellulose and / or paper pulp and / or cotton linter.

9. The method according to claim 8, characterized in that waste paper is used as paper pulp.

10. The method according to at least one of claims 1-9, characterized in that the spinning mass contains as further additives activated carbon, superabsorbers, ion exchange resins, PCM, metal oxides, flame retardants, abrasives, zeolites, phyllosilicates and / or mixtures thereof.

11. Spun nonwovens or yarns of fiber-forming polymers produced from a spinning dope containing fiber-forming polymers in which the spinning dope is spun from at least one spinning bore and the spun yarn is warped by means of a Laval nozzle to high speed steadily accelerated gas streams characterized in that the dope as an additive Contains lignin.

12. Spun nonwovens or yarns according to claim 11, characterized in that they contain 3-20% lignin, based on the fiber-forming polymers.

13. spun nonwoven fabric or yarn according to any one of claims 11 or 12, characterized in that they contain ground wood or wood abrasive dust.

14. Spun nonwovens or yarns according to any one of claims 11 to 13, characterized in that the fiber-forming polymer is polypropylene.

15. Spun nonwovens or yarns produced by the method according to one of claims 1 to 10.