DE19754447A1 - Low odor, reusable fiber composite material - Google Patents

Abstract

A low odor, reusable fiber composite material (I) contains: (A) a polymer having naturalizable acid groups and/or anhydride groups as a binding agent that is water soluble in its neutralized form; and (B) 0.1-30 wt.% activated carbon (wrt the total amount of polymeric binding agent). An Independent claim is included for a process for the production of (I) by mixing fibers with an aqueous dispersion of with respect to and (B).

Description

The present invention relates to low odor, recyclable Fiber composites and a process for their manufacture.

Fiber composite materials are versatile industrial goods ter. These are fiber structures made with polymers Binders are solidified. The increased strength results thereby from the binding of the fibers by the film-forming poly mers that adhere to the fiber and thus reinforce the fiber structures. Basically, it should be borne in mind that the polymer film is made of is sufficiently stable against contact with water so that the fiber ver the mechanical material is sufficient even when wet Possesses strength.

There is a reason for recycling fiber composite materials in addition to their material non-uniformity. That is true Various processes are known, binders and fibers from one another the separate, however, the recycling of the bin turns out because of the difference to the fibers often not possible.

From DE-A 43 15 875 it is known that the polymeric binder Detach nonwovens and the resulting nonwoven to recycle. The binder solution obtained, however, must to be disposed of.

From EP-A 538 625 textile floor coverings are known which by needling a back layer onto a raw material and Im Impregnation of the back layer with a polymer dispersion getting produced. This dispersion can be done with the help of a Solvent are removed from the covering, so that a Recycling of the covering becomes possible in principle; a how however, recycling of the binder is not proposed.

US 3,843,321 describes a process for the recovery of Fibers from nonwovens by covering them with an aqueous solution from alkali metal hydroxide and an organic solvent treated at an elevated temperature. Here, the bindemite telpolymer completely destroyed.

Contains another approach to solving the recycling problem DE 195 35 792, in the fiber composites under use tion of aqueous polymer dispersions. By Treatment with aqueous base systems can remove the polymer from the Fiber composite material can be removed. The Po obtained in this way In turn, polymer solutions can be acidified into aqueous bottoms  transfer lymerisate dispersions (Redispergate), again for the production of fiber composite materials can be used can. However, it proves to be a disadvantage that such polymers risk dispersions and the resulting fiber composite smell unpleasant especially at elevated temperatures. In addition, in the manufacture of fiber composite materials Use of such polymer dispersions an undesirable Formation of aerosols (so-called "qualming"). The problem of Ge nuisance arises particularly in the case of products the basis of fiber composite materials used in automotive construction, ins especially used in vehicle interiors, for example wise wheel arch covers, hat racks, textile floor coverings and Trunk linings. There, especially when the sun is shining radiation, temperatures reached, leading to a noticeable free of odor-forming compounds.

From DE-A 30 23 023 it is known that to reduce Ge odor emission activated carbon can be used. For the use Formation of activated carbon in recyclable fiber composite fen, as proposed by DE-A 195 35 792, provides However, the problem arises that the activated carbon is disruptive can affect aqueous polymer dispersions by Coagulation contributes. This problem will particularly arise occur when aqueous polymer solutions in polymer dispersion NEN, because the activated carbon particles as Koa gulation germs act.

It has now surprisingly been found that activated carbon is on the recycling process proposed by DE-A 195 35 792 does not have a disruptive effect if the activated carbon is used in amounts of 0.1 up to 30% by weight, based on the polymeric binder.

Accordingly, the present invention relates to recycling bare, low-odor fiber composites, very few a poly Contain merisat 1 as a polymeric binder that neutralizes bare acid groups and / or anhydride groups and that in neutralized form is soluble in water, and 0.1 to 30 % By weight, based on the polymeric binder, contains activated carbon The activated carbon is preferably used in amounts of 0.2 to 20 % By weight, in particular 1 to 15% by weight, based on the polymer Binder used.

The activated carbon used preferably has a specific surface area in the range from 500 to 2500 m ² / g, in particular in the range from 800 to 1800 m ² / g and very particularly preferably in the range from 1000 to 1500 m ² / g (Langmuir- Surface, according to DIN 66131). Activated carbon with a high content of pores is preferred. The specific pore volume of the active carbon used is preferably in the range from 0.2 to 1.4 ml / g, in particular 0.4 to 0.8 ml / g. It is further preferred if the active carbon has a high content of micropores (this includes pores with a diameter <2 nm; see also Ullmann, Encyclopedia of Technical Chemistry, 5th edition, vol. A5, p. 126). The pore volume of the micropores is preferably in the range of preferably from 0.2 to 1.4 ml / g, in particular 0.2 to 0.5 ml / g, particularly preferably 0.3 to 0.4 ml / g. Suitable active carbons are commercially available. In principle, finely divided activated carbons with average particle sizes <200 µm, preferably <120 µm, are used. Such activated carbons are known to the person skilled in the art (see, for example, Ullmanns Enzyklopadie der Technischen Chemie, 3rd edition vol. 9, p. 808) and are commercially available. Carbon molecular sieves can also be used in place of or together with the activated carbon. Carbon molecular sieves are e.g. B. from Ullmann's Encyclopedia of Industrial Chemistry, 5th ed. Vol. B3, pp. 9-10, known and commercially available.

As polymer 1, preference is given to using polymers which, in copolymerized form, comprise 50 to 99% by weight, in particular 60 to 95% by weight and particularly preferably 70 to 90% by weight, in each case based on the total weight of polymer 1, monomers A. Contained in polymerised. The monomers A are selected from vinyl aromatic monomers, the esters of ethylenically unsaturated C ₃ -C ₈ monocarboxylic acids and C ₄ -C ₈ dicarboxylic acids with C ₁ -C ₁₂ alkanols, C ₅ -C ₁₀ cycloalkanols or C ₆ - C ₁₀ aryl alcohols, the vinyls of star aliphatic C ₁ -C ₁₂ carboxylic acids, the vinyl ethers aliphatic C ₁ -C ₁₂ alkanols, monoethylenically unsaturated olefins and conjugated dienes. Vinyl aromatic monomers preferably include styrene, α-methylstyrene, vinylnaphthalene, p-tert-butylstyrene, o-, m-, and p-methylstyrene, o-, m- and p-chlorostyrene. Suitable esters of ethylenically unsaturated monocarboxylic acids or dicarboxylic acids are, for example, the esters of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, fumaric acid and itaconic acid. The alcohol component of these esters is preferably selected from C ₁ -C ₈ -alkanols, in particular C ₁ -C ₄ -alkanols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, tert. -Butanol, 2-butanol, n-hexanol, 2-methylpentanol, n-octanol, 2-ethylhexanol, n-decanol, 2-propylheptanol and lauryl alcohol. Furthermore, the esters of the aforementioned ethylenically unsaturated carboxylic acid with C ₅ -C ₁₀ cycloalkanols such as cyclopentanol and cyclohexanol and the esters with C ₆ -C ₁₀ aryl alcohols such as phenol can also be used. The vinyl esters of aliphatic C ₁ -C ₁₂ carboxylic acids include in particular vinyl acetate, vinyl propionate, vinyl esters of (x-branched monocarboxylic acids having 9 to 11 carbon atoms (vinyl versatates) and vinyl laurate. Vinyl ether aliphatic C ₁ -C ₁₂ alkanols include, for example Vinyl methyl ether, vinyl ethyl ether, ethylene glycol methyl vinyl ether, diethylene glycol methyl vinyl ether. Suitable monoethyl nisch unsaturated olefins are ethylene, propene, n-butene, vinyl chloride and vinylidene chloride. Conjugated dienes are, for example, butadiene, isoprene, chloroprene and 1-phenylbutadiene. Preferred monomers are A C ₁ -C ₁₂ alkyl esters of acrylic acid and methacrylic acid, such as methyl acrylate, ethyl acrylate, n- and iso-propyl acrylate, n-, iso- and tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate and the corresponding methacrylates. The preferred monomers A also include styrene and α-methylstyrene.

The polymer 1 further contains in copolymerized form preferably 1 to 50% by weight, in particular 5 to 40% by weight and particularly preferably 10 to 30% by weight of monomers B which are an acid have group and / or an anhydride group. You are out chooses from ethylenically unsaturated monocarboxylic acids and Dicar bonic acids, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphonic acids, the semi-esters ethylenically unsaturated saturated dicarboxylic acids and the anhydrides ethylenically unsaturated ter dicarboxylic acids. Suitable ethylenically unsaturated mono- or Dicarboxylic acids generally have 3 to 8 carbon atoms. These preferably include acrylic acid, methacrylic acid, acrylami doglycolic acid, methacrylamidoglycolic acid, crotonic acid, malein acid, fumaric acid, itaconic acid and citraconic acid. examples for ethylenically unsaturated sulfonic acid or phosphonic acids are Vi nylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, vinyl phosphonic acid, acrylamido-2-methylpropanesulfonic acid, methacryla mido-2-methylpropanesulfonic acid and its salts. Further come as Monomers B also the half esters of ethylenically unsaturated dicarbon acids, e.g. B. monobutyl maleate and monomethyl maleate in question. As monomers B, the anhydrides can also be ethylenically unsaturated ter dicarboxylic acids z. B. maleic anhydride and citraconic acid hydride can be used. Preferred monomers B are acrylic acid, Methacrylic acid, acrylamidoglycolic acid, methacrylamidoglycolic acid and itaconic acid.

In addition to monomers A and B, polymer 1 can optionally be mono mere C in amounts of up to 30 wt .-%, preferably up to 20 % By weight and in particular up to 10% by weight, which he have increased water solubility (i.e. <60 g / l at 25 ° C). These include the amides of the aforementioned ethylenically unsaturated ten carboxylic acids such as acrylamide, methacrylamide, the N-alkylolamides the aforementioned ethylenically unsaturated carboxylic acid, preferred as N-methylol acrylamide, N-methylol methacrylamide, N-hydroxy ethyl acrylamide, N-hydroxyethyl methacrylamide, the hydroxyalkyl esters of ethylenically unsaturated monocarboxylic acids and the hydro  xyalkyl esters of ethylenically unsaturated dicarboxylic acids such as 2-Hy hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypro pyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, the implementation pro Products of acrylic acid, methacrylic acid or maleic acid with Diethy lenglycol or higher polyethylene glycols. Furthermore, as Monomers C acrylonitrile, methacrylonitrile, N-vinyl lactams such as N-Vi nylpyrolidone and N-vinylcaprolactam suitable.

Monomers A, B and C can each be used individually or preferably in mixtures. Preferred polymers 1 contain as monomers A at least one C ₁ -C ₁₂ alkyl acrylate and, if appropriate, a C ₁ -C ₁₂ alkyl methacrylate and as monomers B acrylic acid and / or methacrylic acid.

Particularly preferred monomer combinations for polymers 1 are:

• I. 60 to 85 wt .-% n-butyl acrylate, 2-ethylhexyl acrylate and / or Ethyl acrylate, 5 to 20% by weight acrylonitrile, methyl methacrylate and / or styrene and 10 to 20 wt .-% methacrylic acid or Acrylic acid
• II. 50 to 80 wt .-% n-butyl acrylate, 10 to 50 wt .-% vinyl acetate and / or vinyl propionate and 1 to 30% by weight of acrylic acid and / or methacrylic acid
• III. 30 to 65% by weight of n-butyl acrylate, 30 to 65% by weight of ethyl acrylate lat and 5 to 30 wt .-% methacrylic acid and / or acrylic acid.
• IV. 40 to 80% by weight methyl methacrylate, 5 to 25% by weight n-butyla crylate and / or 2-ethylhexyl acrylate, 10 to 30 wt .-% styrene and 5 to 30% by weight of methacrylic acid or acrylic acid.
• V. 40 to 60% by weight of n-butyl acrylate, 5 to 10% by weight of acrylonitrile, 5 to 30 wt .-% acrylic acid and / or methacrylic acid and 10 to 40% by weight maleic anhydride.

The percentages given relate to the Ge total amount of monomers A + B. In addition, the preferred Mo nomerkombinationen also monomers C in amounts up to 10%, z. B. Include hydroxyethyl acrylate. Furthermore, a part or the Ge total amount, preferably only part of the acrylic acid or metha acrylic acid by acrylamidoglycolic acid and / or methacrylamidogly colic acid to be replaced.  

As a binder for the fiber composite materials according to the invention polymers 1 are preferred whose molecular weight in loading ranges from 10,000 to 200,000 (weight average molecular weight weight determined by means of gel permeation chromatography with tetrahy dropropan as eluents and calibrated polystyrene references).

The molecular weight of the polymers 1 can in a known manner by the type and amount of the initiator system and by the polyme rization in the presence of controllers. Here it is preferably compounds, the thiol group contain and, if the polymerization in water or a aqueous alcoholic reaction medium is carried out before moves to those compounds that are water-soluble. Examples for water-soluble regulators containing thiol groups are ethyl thiol glycolate, 2-ethylhexylthioglycolate, cysteine, 2-mercaptoetha nol, 3-mercaptopropan-1-ol, 3-mercaptoglycerin, mercapto-vinegar acid, 3-mercaptopropionic acid, with 2-ethylhexylthioglycolate preferred among them. Halogenverbin also comes as a regulator such as bromotrichloromethane, tetrabromomethane or tetrachlorme than, linear or branched non-polar aliphatic thiols such as tert-dodecyl mercaptan, 3-mercaptopropyltrimetoxysilane in question. Allyl compounds such as allyl alcohol, Bu tenol, butenediol, allylsulfosuccinic acid esters, aldehydes such as Acetaldehyde, propionaldehyde, benzaldehyde, phosphorus-containing compound such as hypophosphites, especially sodium hypophosphite be applied. The amount of regulator used should be a value of 5% by weight, based on the monomers to be polymerized not exceed. Are regulators for adjusting the molecular Ge weight used, then they are preferably used in quantities from 0.2 to 3% by weight, in particular 0.5 to 2% by weight, based on the monomers to be polymerized.

The monomers are preferably combined in such a way that the resulting polymer 1 has a glass transition temperature in Range from -50 to + 60 ° C, especially -40 to + 40 ° C and whole particularly preferably has -30 to + 30 ° C (determined by DSC according to ASTM D3418-82; mid point temperature). Suitable monomer com binations can be made using known nutritional methods based on the glass transition temperature tabulated in the literature Calculate temperatures for homopolymers (see e.g. Fox, Bull. At the. Phys. Soc. (Ser. II) 1, 1956, p. 123; Ullmann's Encyclopedia of Industrial Chemistry, Vol. A21 (1992), p. 169; J. Brandrup, E.H. Immergut, Polymer Handbook, 3rd ed., J. Wiley, New York 1989).  

The manufacture of the fiber composite according to the invention Substances required polymers 1 are usually made by poly merization of the above monomers in the presence of free radicals Polymerization initiators. For the production of the fiction According to fiber composite materials, the polymers 1 in Re gel used as aqueous polymer dispersions, so that for the preparation of the polymers 1, the radical, aqueous Offers emulsion polymerization. Of course, the polymer sate 1 also produced by radical solution polymerization become. In this case it is advantageous to use the available poly to convert mer solutions into aqueous polymer dispersions (so-called secondary dispersions).

Polymers 1 which are preferred by free radical, aqueous Emulsion polymerization were prepared. For this, the Monomers A, B and C above in the presence of at least one radical polymerization initiator and optionally one surfactant and optionally a Molecular Ge weight regulator in an aqueous reaction medium under intense Mixing polymerized.

All those come as radical polymerization initiators conditions that are capable of a radical aqueous Trigger emulsion polymerization. It can be both Peroxides, e.g. B. alkali metal peroxodisulfates as well as azoverbin act. Combined systems are also used from at least one reducing agent and at least one per oxide and / or hydroperoxide are composed, for. B. tert-Bu tylhydroperoxid with the sodium salt of hydroxymethanesulfinic acid or hydrogen peroxide with ascorbic acid. Also be combi systems used that contain a small amount of one in the polymer contain a soluble metal compound, the me metallic component occur in several valence levels can, e.g. B. ascorbic acid / iron (II) sulfate / hydrogen peroxide, where, instead of ascorbic acid, the sodium salt of Hydroxymethanesulfinic acid, sodium sulfite, sodium hydrogen sulfite or sodium bisulfite and tert-Bu instead of hydrogen peroxide tylhydroperoxid or Alkaliperoxodisulfate and / or ammonium peroxodisulfate can be used. The alkali metals are preferred tall peroxodisulfates. The amount is preferably one set radical initiator systems, based on the total amount of the monomers to be polymerized, 0.1 to 2% by weight.

Limit suitable for carrying out the emulsion polymerization Surfactants are the most common for these purposes protective colloids and emulsifiers used. The interfacial tive substances are usually used in amounts of up to 10% by weight,  preferably 0.2 to 5% by weight and in particular 0.5 to 3% by weight, based on the monomers to be polymerized.

Suitable protective colloids are, for example, polyvinyl alcohols, starch and cellulose derivatives or copolymers containing vinylpyrrolidone. A detailed description of other suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Substances, Georg-Thieme-Verlag, Stuttgart 1961, pp. 411-420. Mixtures of emulsifiers and / or protective colloids can also be used. Preferably only emulsifiers are used as surface-active substances, the relative molecular weights of which, in contrast to the protective colloids, are usually below 2000. They can be both anionic, cationic and nonionic in nature. The anionic emulsifiers include alkali and ammonium salts of alkyl sulfates (alkyl radical: C ₈ -C ₁₂ ), of sulfuric acid half-esters of ethoxylated alkanols (EO degree: 2 to 50, alkyl radical: C ₁₂ to C ₁₈ ) and ethoxylated alkylphenols (EO Grade: 3 to 50, alkyl radical: C ₄ -C ₁₂ ), of alkyl sulfonic acids (alkyl radical: C ₁₂ -C ₁₈ ) and of alkylarylsulfonic acids (alkyl radical: C ₉ to C ₁₈ ). Further suitable emulsifiers can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Substances, Georg-Thieme-Verlag, Stuttgart, 1961, pp. 192-208). Preferred are anionic emulsifiers and in particular the salts of the aforementioned alkyl sulfonic acids, the sulfuric acid half-esters of ethoxylated alkanols and the sulfuric acid half-esters of the ethoxylated alkylphenols, very particularly preferably the sodium salts. Further suitable anionic emulsifiers are alkylated bis (sulfonato phenyl) ether, or their alkali metal or ammonium salts, which carry a C ₄ -C ₂₄ -alkyl group on one or both aromatic rings. Such connections are e.g. B. from US-A 4,269,749. A mixture of mono- and dialkyl compound is commercially available under the name Dowfax® 2A1 (trademark Dow Chemical).

In addition to the ionic emulsifiers mentioned, it is also possible to use one or more nonionic emulsifiers in amounts of preferably 0 to 10% by weight, in particular 0.5 to 8% by weight and particularly preferably 1 to 4% by weight, in each case based on use the total amount of monomer. Suitable nonionic emulsifiers are arali phatic or aliphatic nonionic emulsifiers, for example ethoxylated mono-, di- and trialkylphenols (EO grade: 3 to 50, alkyl radical: C ₄ -C ₉ ), ethoxylates of long-chain alcohols (EO grade: 3 to 50 , Alkyl radical: C ₈ -C ₃₆ ), and polyethylene oxide / polypropylene oxide block copolymers. Ethoxylates of long-chain alkanols (alkyl radical: C ₁₀ -C ₂₂ , average degree of ethoxylation: 10 to 50) are preferred, and among them those with a linear C ₁₂ -C ₁₈ alkyl radical are particularly preferred.

The emulsion polymerization can be both continuous and according to the batch mode, preferably after a semi-continuous process. The ones to be polymerized can Monomers continuously, including step or gradient way, the polymerization approach.

The monomers are preferably added in the form of an aq monomer emulsion, which in addition to the monomers, water and a Contains part of the surfactant.

In addition to the seed-free production method, a defined polymer particle size according to the emulsion polymerization the seed latex process or in the presence of in situ seed latex. Methods for this are known and can can be found in the prior art (see EP-B 40419, EP-A 129 699, EP-A 567 812, EP-A 614 922 and "Encyclopedia of Poly Science and Technology, "Vol. 5, John Wiley & Sons Inc., New York 1966, p. 847).

Polymerization pressure and polymerization temperature are of un secondary importance. Generally one works at Tempera structures between room temperature and 120 ° C, preferably at tempera tures from 40 to 95 ° C and particularly preferably between 50 and 90 ° C.

Following the actual polymerization reaction it is if necessary, the aqueous poly according to the invention Merisate dispersions largely free of odorants, like the rest monomeric and other organic volatile constituents design. This can be done physically in a manner known per se removal by distillation (especially by steam distillation tion) or by stripping with an inert gas the. The lowering of the residual monomers can continue chemically radical post-polymerization, especially under the action of redox initiator systems, such as e.g. B. in DE-A 44 35 423, DE-A 44 19 518 and DE-A 44 35 422 are listed, he consequences.

In a preferred embodiment of the present invention the polymers 1 by a gradual polymerization process manufactured. For this, two or more Monomermi creations that differ in their composition, time Lich successively fed to the polymerization reaction. The polymers obtainable here are preferred because the hy  more hydrophilic phases in the edge areas of the polymer part and enrich the dispersion process of the later binder support.

It has proven beneficial for a number of applications proven when used for the manufacture of fiber composites aqueous polymer dispersion used in addition to the polymer 1 contains a further polymer 2, which has a glass transition temperature temperature above 60 ° C. Polymer 1 then has preference have a glass transition temperature in the range of -50 to + 60 ° C on. The glass transition temperature preferably differs Ren of polymer 1 and polymer 2 by at least 20 ° C, ins especially at least 40 ° C. The weight ratio of polymer 1 and polymer 2 in the for the fiber ver polymer dispersions used in composite materials is in the ver Ratio of 10: 1 to 1:10, preferably 4: 1 to 1: 4 and completely particularly preferably 2: 1 to 1: 2. The preparation of the polymer dispersions containing both polymer 1 and polymer 2 can contain conventionally by mixing two polymers dispersions or by step polymerization (see above), preferably first polymer 1 and then Po lymerisat 2 produces. By using such polymer leave dispersions as binders for fiber composites thermoplastic deformable fiber composites len.

In principle, all conventional polymers with a glass transition temperature of <60 ° C. are suitable as “hard” polymers. Polymers composed of monomers A and B are preferred, the glass transition temperature being set by combining different monomers A, ie at least one “hard monomer and at least one“ soft ”monomer (see above). Such monomers are referred to as“ hard ” whose homopolymers have a glass transition temperature T _G <60 ° C, as "soft" all those whose homopolymers have a glass transition temperature T _G <30 ° C. The monomers A of the "hard polymer phase" are preferably identical to the monomers A. the "soft" phase, ie "hard and soft phase" differ only with respect to the monomers A in the relative monomer amounts. The hard phase preferably contains 50 to 100% by weight of "hard" monomers, eg styrene, α -Methylstyrene and / or C ₁ -C ₄ -alkyl methacrylates, such as methyl methacrylate or t-butyl methacrylate and 0 to 50% by weight of "soft" monomers, for example butadiene and / or C ₁ -C ₈ -alkyl acrylates, in particular Ethyl acrylate, n-butyl acrylate and / or 2-ethylhexyl acrylate. The "hard" phase can also contain crosslinking monomers, ie monomers with at least two polymerizable double bonds, in a polymerized form. In the "soft" phase, however, the "soft" monomers predominate. The "hard" phase can be made water-soluble or water-dispersible by the amount of monomers B and C used. However, this is not absolutely necessary, since a recovery of the "soft" phase is surprisingly independent of this, and the "hard" phase can be recovered in another way.

Preferred “hard” polymers 2 are those which are present of alkali are water-soluble or water-dispersible. To this Purpose is polymerized in the production of polymer 2 those monomer mixtures which, in addition to the monomers A, are preferred 5 to 40 wt .-% and in particular 10 to 30 wt .-%, based on the total amount of monomers, monomers B and optionally 0.5 to Contain 20% by weight of copolymerized monomers C. The monomers A advantageously comprise at least 30% by weight of a monomer A1, based on the total amount of monomers A, with a Was ser solubility in the range of 0.5 to 60 g / l (at 25 ° C), e.g. B. Methyl methacrylate, methyl acrylate or ethyl acrylate. Preferably in this case, the polymers 2 by polymerization in Ge present from 0.2 to 5 wt .-%, based on the total amount of Polymer 2 forming monomers, molecular weight regulators poses.

The for the manufacture of the fiber composite according to the invention Polymer dispersions used generally have a polymer content in the range of 30 to 70 wt .-%, based on the total weight of the polymer dispersion, preferably 40 up to 68% by weight and in particular 45 to 65% by weight.

The production of the fiber composite materials according to the invention follows preferably by solidifying fibers or fiber structure in the presence of 0.1 to 30 wt .-%, based on the polymer sat 1, one or more of the activated carbons described above. As a rule, the activated carbon is used according to conventional ver drive as they do for the addition of powdered solids Polymer dispersions are known, for example by means of egg nes dissolver, into the aqueous polymer dispersion The thus obtainable, activated carbon-containing dispersion of the polyme Risats 1 and optionally the polymer 2 can in this Form used for the production of fiber composite materials become. Here, however, conventional additives can also be known Amounts are added. Suitable additives include additives such as Plasticizers, defoamers, substances for pH regulation lation, external crosslinking agents such as melamine or formaldehyde Urea-formaldehyde resins, flame retardants, wetting agents, pig elements, thickeners, lubricants, antifreeze, paints  substances, perfumes, biocides etc. These additives are known to the expert known and can without loss of characteristic Eigen be added to the dispersion. Furthermore, the Dis Persions of the polymer 1 before or after the addition of the active Carbon water repellant can be added. This will make the Wet strength of the fiber composite materials increased, which in particular is of particular interest if the fiber according to the invention composite materials as interlining nonwovens for clothing fabrics, the to be washed or dry cleaned, or for hygiene net towels, for insoles that partially under conditions of use can become damp or wet. Suitable hy Drophobing agents include agents based on fluoroorganic Compounds or silicone compounds, such as copolymers, the fluorinated monomers and / or copolymerizable silicon compound polymerized doses contain z. B. acrylate-modified Si licone (Tegomer® grades from Goldschmidt AG). More water repellent medium are the solutions of salts of perfluorinated carboxylic acids or aqueous dispersions of organofluorine polymers.

The for the manufacture of the fiber composite according to the invention Fabrics required fibers are based on a person skilled in the art known manner according to the respective purpose. Basically however, all common fiber materials can be used. In addition to synthetic fibers such as viscose, poly ester, polyamide, polypropylene, polyacrylonitrile, carboxylic acid fibers or fibers of homopolymers and copolymers of vinyl chloride rids or tetrafluoroethylene, also fibers of natural origin, such as cellulose, cellulose, cellulose, cotton or wood fa star, also glass, ceramic or mineral fibers or mixtures of this. Mixtures are made from thermoformed needle felt Polyester and polypropylene or polyamide fibers preferred. For So - called disposables (hygiene articles and nonwovens for the Clothing industry) become polyester, cellulose or cell fabric fibers or polyester / pulp mixed fibers are preferred. For Disposables can also be made from polyester-based fibers 3-hydroxybutyrate, 3-hydroxyvalerate and 4-hydroxyvalerate be set. Such fibers are for example in EP-A 466 050. Fibers suitable for disposables have been shown preferably diameters from 0.002 to 0.1 mm, in particular 0.01 to 0.05 mm, the diameter in the usual way using can be determined from electron micrographs.

The fibers are usually not as such, but in one prefabricated form used. Methods for this are the expert known (see e.g. Römpp, Chemielexikon, Georg-Thieme-Verlag, Stuttgart / New York, 9th ed., P. 4550; Ullmann 's Encyclopedia of technical chemistry, 4th edition, volume 23, 1983, p. 733 ff.). Depending on  The application form can be a needle punch or we res or, preferably, directional nonwoven, the opposite is also mechanically prefabricated, for example by Na twisting, swirling or sewing.

The consolidation of the nonwoven or needle-punched nonwovens with the polyme risks to the fiber composite materials according to the invention using known methods (e.g. Ullmann's encyclopedia of techni chemistry, 4th edition, volume 23, 1983, pp. 738-742). Usually the fiber structure is impregnated with bath, foam impregnated kidney, spray, splash or print with the activated carbon containing polymer dispersion of polymer 1 and given if the polymer 2 soaked. The dispersion can even diluted with water or with conventional thickeners, e.g. B. starches, modified starches, polyvinylpyrrolidones, copo lymeren of vinyl pyrrolidone, e.g. B. with vinyl acetate, polyacrylic acids, polyvinyl alcohols, can be thickened to the desired Adjust processing viscosity. The fleece treatment with the Dispersion generally includes drying and tempering tion of the fiber composite material obtained. The drying area conditions naturally depend on the type of drying used ners and the desired fiber composite material. More common however, the drying temperature is between 100 and 230 ° C; the drying time is usually between 10 seconds and 60 minutes.

The fiber / binder polymer ratio (i.e. polymer 1 + optionally polymer 2) can, depending on the desired application Range from 1: 5 to 50: 1, preferably 1: 2 to 20: 1. For most applications are the fiber / binder po ratio lymer in the range from 1: 1 to 10: 1.

An important embodiment of the present invention relates to so-called thermoformable fiber composites. Such Fiber composite materials usually contain polymer 1 and at least one further polymer 2 with the egg mentioned above properties. Polymer 1 and polymer 2 can be separated be prepared polymers or step polymers (see above). This ensures that the fiber composite fabrics rigid at low temperature, but at elevated temperatures temperature are flexible and can therefore be processed thermoplastically.

Such fiber composites are used for thermoformable needle punched nonwovens, such as those found in automo bilbau can be used. In this case the ratio is from Polymer 1 to polymer 2 in the range from 1: 4 to 4: 1 preferably 3: 1 to 1: 3.  

The fiber composite materials according to the invention are characterized by one from the fact that it is also exposed to thermal stress at 70 ° C do not tend to emit unpleasant odors. Furthermore, no undesirable aerosol formation occurs during processing observed (so-called "qualming"). Fiber composite according to the invention fabrics used in automotive interior lining are also not prone to so-called "fogging", d. H. for the emission of compounds that turn out to be thinner Lubricant film on shiny surfaces, such as the windshield, to make noticable. The mechanical properties of the Invention according fiber composite materials in turn correspond to the fiber composite Bund materials made without the use of activated carbon become. (For the problem of fogging see e.g. P. Ehrler et al., Textilveredlung 29 (1994), pp. 254-260.)

Another important advantage of the fiber composite materials according to the invention is the fact that both the fibers used and the polymer 1 and the polymer 2 can be recycled. For this purpose, the fiber composite materials according to the invention are treated with an aqueous, alkaline solution of a low molecular weight, organic and / or inorganic base, preferably an inorganic base. As a result, the polymeric binder is released from the fiber composite material and the fiber composite material breaks down into the fibers or a fiber structure and an aqueous solution of the binder polymer. The activated carbon will usually accumulate in dispersed form in the aqueous solution of the binder polymer. The treatment of the fiber composite material with the alkaline solution can be carried out both at room temperature and at an elevated temperature, e.g. B. up to 80 ° C. The alkaline solution used to remove the polymer contains an alkali metal hydroxide, e.g. B. NaOH, or an alkali metal carbonate, e.g. B. Na ₂ CO ₃ . Aqueous ammonia solutions, preferably with 5 to 30% by weight of NH ₃ , can also be used as the alkaline solution. In addition, the alkaline solution can neutral or anionic wetting agents, e.g. B. the above emulsifiers and / or bis-C ₄ -C ₁₂ alkylsulfosuccinic acid, z. B. Contain bis (2-ethylhexyl) sulfosuccinate. Such wetting agents are preferably used in amounts of up to 5% by weight, and in particular in amounts of 0.1 to 2% by weight, based on the total weight of the aqueous alkaline solution. The concentration of base is preferably in the range from 0.1 to 10% by weight and preferably 0.2 to 5% by weight, based on the aqueous solution. The treatment of the fiber composite material with this alkaline aqueous solution naturally depends on the shape and type of the fiber composite material and can be done, for example, by rinsing or spraying the fiber composite material with the alkaline solution. In the treatment of the fiber composite material with the alkaline solution, on the one hand the fibers or fiber form freed from the binder polymer and on the other hand an aqueous, alkaline solution of the binder polymer in which the activated carbon has accumulated. This solution is separated from the fibers, e.g. B. by filtration, and then ver with an acid. Here, an aqueous, activated carbon-containing polymer dispersion (redisperse) is formed from the aqueous, activated carbon-containing solution of the binder polymer. This redisperse generally contains the main amount of activated carbon contained in the fiber composite material and can thus, if necessary after concentration and compensation of activated carbon and additive losses, be reused directly for the production of the fiber composite materials according to the invention. The redisperse is preferably used together with a fresh dispersion of the binder polymer, to which the amounts of activated carbon and / or additives still required were optionally used for the production of the fiber composite material according to the invention.

The method according to the invention for reusing fiber Bundwerkstoffe is characterized in particular by the fact that all Components can be reused. For example also show the fibers or the fibrous structures, after separating the Polymer solution and optionally after drying processes, the production of the fiber composite materials according to the invention such as which are fed. This may be in the binder poly Polymer 2 present has an effect on the invention according to the procedure not disruptive. Depending on the nature of this polymer It becomes risky 2 together with the polymer 1 from the fiber composite material detached or remains on the fiber and can after drying the fibers or the fiber structures mechanical processes, for example by tapping, from the Fibers are separated.

Examples I. Preparation and characterization of the polymeric binder 1. Analytics

The particle size of the polymer particles was determined by dy Namely light scattering on a 0.01% by weight disper sion at 23 ° C using an Autosizer IIc from Mal vern Instruments, England. The is given So-called z-mean diameter, as it emerges from the cumulan  evaluation of the measured autocorrelation function gives.

The glass transition temperature of the polymer was measured at Po films made by pouring the aqueous polymer sat dispersions were obtained by means of DSC (midpoint Method) determined according to ASTM D 3418-82.

The pH of the dispersions was determined with a Glass electrode.

2.Dispersion D1 (hard component)

A mixture of was in a polymerization reactor 600 g of water and 45 g of monomer emulsion presented and on Heated to 80 ° C. 1.5 g of initiator solution were then added to. After 15 minutes, the handover started, at the same time separate feeds within the rest of the monomer emulsion 2 hours, and the rest of the initiator solution within 135 minutes too. After the addition of initiator has ended the 80 ° C was maintained for a further 60 minutes. Subsequently it was cooled to room temperature and the contents were transferred tene dispersion with 1.32 g of tert-butyl hydroperoxide and 1.32 g isoascorbic acid (each in the form of dilute, aqueous solutions). A coagulate-free, about 50 wt .-% aqueous dispersion with a residual monomer hold (acrylate ester) of about 200 ppm.

The glass transition temperature of the polymer was 111.9 ° C. The average particle size of the polymer part Chen was 126 nm. The pH was 5.0.

The aqueous monomer emulsion had the following composition:

358 g methyl methacrylate
65 g of n-butyl acrylate
130 g styrene
98 g methacrylic acid
9 g of tert-dodecyl mercaptan
8.0 g of 25% by weight sodium hydroxide solution
46 g of a 25% by weight solution of the sodium salt of sulfated nonylphenyl ethoxylate; Texapon® NSO from Henkel KGaA
320 g water.

Composition of the initiator solution:

7.5 g sodium peroxodisulfate
290 g water

3.Dispersion D2 (soft component)

Analogous to dispersion D1, an aqueous polymer dispersion was prepared. The monomer emulsion had the following composition:

240 g of n-butyl acrylate
273 g of ethyl acrylate
87 g methacrylic acid
6 g of tert-dodecyl mercaptan
7 g 25% by weight sodium hydroxide solution
30 g Texapon® NSO
270 g water.

A 50% by weight, coagulate-free dispersion was obtained with a residual monomer content of about 100 ppm (acrylic ester).

The glass transition temperature of the polymer was -2.2 ° C. The average polymer particle diameter was at 164 nm. The polymer dispersion had a pH from 3.9 to.

II. Production of a fiber composite material according to the invention

60 parts by weight of dispersion D1 and 40 parts by weight of Disper sion D2 were mixed together and by adding Na tron liquor adjusted to a pH of 5.5. Subsequently was made by adding a 10 wt .-% aqueous solution solution of a vinyl pyrrolidone copolymer (Collacral® VL from BASF AG) a processing viscosity of about 2,000 mPas. To 5 parts by weight of activated carbon (Carboraffin® P from Lurgi). The dispersion thus obtained is using foulard rollers on a commercially available polypropylene / Polyester needle fleece applied on one side. The order quantity is about 45.3 g polymer per 100 g needle fleece (ent speaks about 100 g dispersion per 100 g fleece). Subsequently the fleece thus coated was dried at 120 ° C. cupboard dried to constant weight. Subsequently the samples were kept in the climatic room for 20 hours.

Carboraffin® P:

Langmuir surface (according to DIN 66131): 1213 m ² / g
Micropore volume: 0.357 ml
average pore diameter (according to Langmuir): 19 Å

III.Separation of the binder from the nonwoven and redispersion of the separated binder a) Separation of the binder

Samples of the back-coated fleece from II were 2 hours at 70 ° C in a 25 wt .-% ammonia solution solution stirred. Then the mixture was cooled From room temperature and filtered the fibers. Man he kept a stable suspension containing activated carbon. On in this way approx. 95% binder + activated carbon were added recovered.

In a comparable experiment with a back coating The nonwoven containing no activated carbon lay on the back extraction at about 98%.

b) recovery of the binder

The filtrates from a) were mixed with 15% by weight, aqueous sodium lauryl sulfate solution until the sodium laud ryl sulfate content at about 1 wt .-%, based on the Ge total weight of the mixture. Then you warmed up to 90 ° C and adjusted the pH with 5 wt .-% salt acid with stirring to a value of about 3.0. Man received a finely divided polymer dispersion. The Aktivkoh Particles settle. The polymer content of the so he holding fleet was about 10 wt .-%. The particle size the redispersed, finely divided dispersion was with be light scattering in the manner described above true and was around 120 nm. For comparison purposes the poly obtained from the activated carbon-free fleece mer solution redispersed in the manner described above. The particle size of the dispersion thus obtained was about 75 nm.

IV. Odor and smoke test

100 parts each of the thickened, aqueous polymer dispersion II became O, 1, 5 and 10 parts by weight of activated carbon transferred. Then, as described in II,  a one-sided coated needle fleece. The used Needle fleeces were previously used to remove finishing agents with Was rinsed out.

With the coated needle punched nonwovens thus obtained, a Odor test at 70 ° C, at 80 ° C and a smoke test carried out. The results are summarized in Table 1 sums up.

A. Odor test at 70 ° C

A rectangular test specimen (7 × 24 cm) is placed in a 3 l Wide neck bottle and this bottle with egg a glass stopper with a piece of filter in between paper sealed. It then turns on for 20 hours 70 ° C heated in a drying cabinet. Then leaves to cool the bottle to room temperature for 1 hour and then exchange the glass stopper for a flat glass cover out.

The assessment is done by holding your breath, pushing the lid of the jar aside and at the same time sticking your nose as far as possible into the opening, inhaling a small amount of air in several portions and then immediately closing the jar again . Depending on the perceived odor intensity, the sample is assessed on the following scale:

0 = odorless
1 = just perceptible
2 = clearly perceptible
3 = noticeable, but not disturbing
4 = tolerable
5 = just tolerable
6 = disturbing
7 = annoying
8 = very annoying
9 = unbearable.

Then let two to three breaths pass to condition and smell again judge the next rehearsal. If you judge all the samples has been reassessed so that you start with the lowest grade in the rehearsal. On this leads to a final assessment of the respective sample. The samples are checked by six examiners  assessed and then the mean of each Assessment formed.

B. Odor test at 80 ° C

The test is carried out analogously to the test at 70 ° C with the following changes:

• - The test specimen has an area of 150 cm ²
• - The bottle is stored at 80 ° C for 2 hours.
• - After removal from the drying cabinet, the test vessel first cooled to 60 ° C and the odor test guided.
• - After the assessment by three examiners, the container becomes he now stored at 80 ° C for 30 minutes and then at 60 ° C a further test by other examiners guided.
• - The following odor scale is used:
  
  • 1 = imperceptible
    2 = noticeable, not distracting
    3 = clearly perceptible, but not yet disturbing
    4 = disturbing
    5 = very annoying
    6 = unbearable.

C. Smoke test

A test specimen (31 × 8 cm) is measured using an infrared heater heated to 230 ° C. The aero formed in the process brine under side lighting in front of dark background observed and assessed according to their intensity. The intensity scale ranges from 0 for no noticeable Quality development up to 5 for a very strong quality development lung. Intermediate grades can also be awarded. The Testing is carried out twice for each sample. The he result is the worst value. The results from A. to C. are summarized in Table 2.  

Table 1

Claims (10)

1. Low-odor, recyclable fiber composite materials, ent holding at least one polymer as a polymeric binder 1, the neutralizable acid groups and / or anhydride groups which is water-soluble in neutralized form, and 0.1 to 30% by weight based on the total polymeric bin detergent, activated carbon. 2. Fiber composite materials according to claim 1, wherein the activated carbon has an average particle size below 200 microns. 3. Fiber composite materials according to one of claims 1 or 2, where in the polymer 1 in copolymerized form, based on the total weight of the polymer 1,

• 50 to 99% by weight of monomers A, selected from vinyl aromatic monomers, the esters of ethylenically unsaturated C ₃ -C ₈ monocarboxylic acids and the diesters of ethylenically unsaturated C ₄ -C ₈ dicarboxylic acids with C ₁ -C ₁₂ alkanols, C ₅ -C ₁₀ cycloalkanols, C ₆ -C ₁₀ aryl alcohols, the vinyls of star aliphatic C ₁ -C ₁₂ carboxylic acids, the vinyl ethers of aliphatic C ₁ -C ₁₂ alkanols, monoethylenically unsaturated olefins and conjugated, diethylenically unsaturated olefins ,
• - 1 to 50 wt .-% of monomers B, which are selected from ethylenically unsaturated C ₃ -C ₈ monocarboxylic acids and C ₄ -C ₈ dicarboxylic acids, ethylenically unsaturated sulfonic acids, ethylenically unsaturated phosphonic acids, semiesters of ethylenically unsaturated C ₄ -C ₈ -dicarboxylic acids and anhydrides of ethylenically unsaturated dicarboxylic acids and
• - 0 to 30 wt .-% of monomers C, selected from the amides and the N-alkylolamides of ethylenically unsaturated C ₃ -C ₈ monocarboxylic acids, the hydroxyalkyl esters of ethylenically-unsaturated C ₃ -C ₈ monocarboxylic acids, the ethylenically unsaturated C ₄ Bishydro xyalkylestern -C ₈ -dicarboxylic acids and ethylenically unsaturated nitriles,
  contains.

4. Fiber composite materials according to one of the preceding claims che, the polymer 1 by radical, aqueous Emulsion polymerization of the monomers mentioned in claim 3 is available.   5. Fiber composite materials according to one of the preceding claims, wherein the polymer 1 has a glass transition temperature T _G (DSC) in the range from -50 to + 60 ° C. 6. Fiber composite materials according to claim 5, wherein the polymer Binder additionally a different from polymer 1 Polymer 2 with a glass transition temperature above 60 ° C includes. 7. Fiber composite materials according to claim 10, in the form of a ther mouldable needle fleece. 8. Process for the production of low-odor fiber composite materials according to one of the preceding claims, such that the Fibers solidified by means of an aqueous polymer dispersion be at least one as in one of claims 1 and 3 to 6 defined polymeric binder and 0.1 to 30 % By weight of activated carbon, based on the polymeric binder, ent holds. 9. The method according to claim 8, characterized in that the Polymer dispersion ent an activated carbon according to claim 2 holds. 10. The method according to claim 8 or 9, characterized in that at least partially a redisperse is used as the polymer dispersion, which was obtained by

• i) treatment of a fiber composite material according to one of claims 1 to 7 with the aqueous solution of a low molecular weight, organic or inorganic base;
• ii) separating the aqueous polymer solution thus obtained from the fibers; and
• iii) converting the polymer solution freed from the fibers into an aqueous polymer dispersion (redisperse) by adding an acid.