DE19711023A1 - Aqueous polymer binder dispersion for biodegradable fibrous composite - Google Patents

Abstract

The use of aqueous polymer dispersions containing natural or synthetic phospholipid(s) for producing compostable fibrous composites is claimed.

Description

The invention relates to the use of aqueous polymer dispersion NEN, which contain at least one phospholipid, for the preparation compostable fiber composites.

Fiber composites, also known as nonwovens are industrial bulk goods (see Ullmann’s Encyclopedia der technical chemistry, 4th edition, volume 23, 729 ff.). Your fro position is achieved by solidifying fiber structures with polyme ren binders. A key problem with these substances is theirs Disposal, whereby not only used fiber composite materials, but also the waste that arises during their production and their elimination are increasing difficulties for manufacturers rides, must be taken into account.

In principle, there are two ways of solving this problem followed:

• a) Recyclable design of the fiber composite materials
• b) compostable design of the fiber composite materials.

During path a), especially with high-quality fiber composite path b) offers due to the lower Cost advantages with the cheaper textile products Basis of nonwovens, for example hygiene items such as Win deln, cleaning cloths and wipes, medical items such as monthly bin den, towels, bed linen, underwear and blankets, but also Fil Terpapiere, shaping insert and lining materials in the clothing industry and technical products, e.g. B. Laminates for rollers, bearing shells, insulation materials, mats, floor coverings.

Compostability is generally understood to be degradable through a rotting process in composting plants. The pro Products should quickly lose their strength in contact with earth and decay.

Prerequisite for the successful rotting of fiber composite The first is the biodegradability of the fibers. However, this alone is not sufficient, as this is usually biolo non-biodegradable synthetic binder polymer The fiber is covered and the bacteria have access to the degradable one Fiber closes. The use of a biodegradable However, dispersants open up the possibility in favorable cases  possibility of bacterial access, even if aqueous polymer sat dispersions are used as binders. At this It should be noted that the use of biodegradation The dispersant does not necessarily lead to decomposable fiber leads like tests with potassium oleate as a disperser have shown greed.

DE-A-23 61 468 describes a bonded nonwoven fabric that of short fibers such as cellulose fibers and a binder which is a blend of a polymer risk of ethylenically unsaturated monomers and naturally occurring polymers such as gelatin, collagen or starch. The Mixture is applied to the nonwoven fabric from an aqueous medium and removed the water. The bonded nonwovens are indeed biodegradable, but have only low wet strength and only moderate softness.

EP-A-345566 relates to binders based on a copolymer from hydroxyl-free monomers and those containing hydroxyl groups Components such as polyvinyl alcohol, starch, starch derivatives or colloidal cellulose. The polymers are in this binder by adding 1,3-dimethyl-4,5-dihydroxyimidazolidinone ver nets. These products also have poor wet strength and an unfavorable softness.

Those with better properties are waiting for those described in EP-A-591821 NEN nonwovens that are bound with saccharide graft polymers they are. However, here is the tear strength of the bound Nonwovens for some applications are not yet satisfactory lend.

German patent application P 41081706 describes a polymer sat by emulsion polymerization in the presence of proteins how casein or soy protein is produced and that is for the Production of films or coatings, for example Paper, suitable. When used as a binder for fiber Nonwovens become too stiff and not very waterproof fiber composite receive fabrics.

The present invention has for its object a To provide fiber composite material that is compostable, without significantly affecting mechanical properties.

Surprisingly, this task could be solved by a polymer dispersion used as a binder, which a Phos contains pholipid as a dispersant. Such polymer dispersions  are known in principle and described in DE 44 43 887, to which reference is made in full below.

The invention therefore relates to the use of aqueous Polymer dispersions that are at least one natural or synthetic contain table phospholipid, for the production of compostable Fiber composite materials. In the used according to the invention Phospholipids are compounds of the general Formula I,

wherein
R¹ for the acyl radical of an aliphatic C₈-C₂₆-carboxylic acid, the acyl radical of a mono- or polyunsaturated aliphatic C₈-C₂₆-monocarboxylic acid, or the acyl radical of a C₈-C₂₆-monocarboxylic acid, which consists of the corresponding mono- or polyunsaturated aliphatic monocarboxylic acid is obtainable by partial or complete hydroxylation of the unsaturated functions,
R² and R³ independently of one another for H, H₂-CH₂-O _m H with m = 1 to 50,
-SO₃H, -PO₂H₂, an acyl group such as R¹ or

stand,
R⁴ is C₁-C₅ alkyl, with the proviso that either R² or R³ is

stands,
and / or a salt of a compound of general formula I.

Preferred compounds of the formula I are those in which R 1 is the Acyl residue of an aliphatic monocarboxylic acid with a straight line Number of carbon atoms. The number of carbon atoms in R¹ is be preferably 12 to 24, in particular 14 to 22 and very particularly be preferably 16 to 18. Furthermore, it is advantageous if R 1 is unbranched is. The above statements also apply to R² or R³ if these are an acyl group such as R¹.

In particular, those compounds are preferred in which R¹ of palmitic acid (CH₃- (CH₂) ₁₄-COOH), stearic acid (CH₃- (CH₂) ₁₆-COOH), oleic acid (CH₃- (CH₂) ₇-CH = CH- (CH₂) ₇-COOH), linole acid (CH₃- (CH₂) ₄-CH = CH-CH₂-CH = CH- (CH₂) ₇-COOH, linolenic acid (CH₃-CH₂-CH = CH-CH₂-CH = CH-CH₂-CH = CH- (CH₂) ₇-COOH), palmitoleic acid (cis-9-hexadecenoic acid) or arachidonic acid (5,8,11,14-eikosa tetraenoic acid).

Preferred compounds I are furthermore those in which R² or R³ represents a hydrogen atom, among which there are in turn are added, in which R² represents a hydrogen atom.

Furthermore, those compounds I are advantageous in which
Z = CH₂-CH₂-N⊕ (CH₃) ₃⊖OH, CH₂-CH₂-NH₂ or C₆H₆ (OH) ₅.

Those compounds I which are the first are particularly advantageous Having features listed as preferred at the same time.

Mixtures of compounds I are also suitable, such as, for. B. in egg, soybean or rapeseed lecithin (expanded usage) are contained, or derived from them. This applies in particular to enzymatically hydrolyzed lecithin, from which a fatty acid chain is split off by enzymatic treatment, ie is replaced by a hydroxyl group. But it also applies to hydroxylated lecithin (saturation of fatty acid double bonds with hydroxyl groups) or acetylated lecithin (addition of carboxylic acid
residues on the free amino group of the CH₂-CH₂-NH₂ Z radical) and in the aforementioned manner multiply modified lecithin.

Suitable lecithins or modified lecithins of the general Formula I are the Lipotine® from Lucas Meyer GmbH & Co., Ham Castle. This applies in particular to Lipotin 100, Lipotin SB, Lipotin 100J, Lipotin H, Lipotin NE, Lipotin NA, Lipotin AN, but also Lipopur®.

Suitable salts of the compounds of the general formula I come especially their alkali metal (e.g. Na, K) and Ammonium salts into consideration.

In addition to the compounds of general formula I and their salts can stabilize aqueous polymer dis persions also others, especially in the context of radical water Emulsion polymerizations commonly used Disper yaws can also be used. As such, protection comes colloids as well as emulsifiers. Appropriate protection Colloids are, for example, polyvinyl alcohols, cellulose derivatives or polyvinyl pyrrolidones. The emulsifiers can be anionic, be cationic or non-ionic in nature. Common emul gators are e.g. B. ethoxylated mono-, di- and trialkylphenols (EO grade: 3-100, alkyl radical: C₄-C₁₂), ethoxylated fatty alcohols (EO grade: 3-100, alkyl radical: C₈-C₁₈), and alkali and ammonium salts of alkyl sulfates (alkyl radical: C₈-C₁₆), of sulfuric acid half-star ethoxylated alkanols (EO grade: 1-70, alkyl residue: C₁₂-C₁₈) and ethoxylated alkylphenols (EO grade: 3-100, alkyl balance: C₄-C₁₂), of alkyl sulfonic acids (alkyl radical: C₁₂-C₁₈) and of Alkylarylsulfonic acids (alkyl radical: C₉-C₁₈).

Other suitable emulsifiers such as the alkali salts the sulfosuccinic acid diesters are in Houben-Weyl, methods of Organic Chemistry, Volume XIV / 1, Macromolecular Substances, Georg-Thieme Verlag, Stuttgart 1961, pages 192-208. Before surfactants that are biologically active are added have it dismantled and that itself or its degradation and secondary products are not toxicologically harmful, such as sodium lauryl sulfate.

Other suitable surfactants have also been found Compounds of the general formula II

wherein A¹ and A² are hydrogen or C₄- to C₂₄-alkyl and are not simultaneously hydrogen, and X and Y are independent of each other for alkali metal ions and / or ammonium ions, preferably wise sodium, stand, proven. In formula I, A¹ and A² prefers linear or branched alkyl radicals with 6 to 18 C atoms, in particular with 6, 12 or 16 C atoms or hydrogen. Compounds II in which X and Y are particularly advantageous Sodium, A¹ is a branched alkyl radical with 12 C atoms and A² Is hydrogen or A¹. Technical mixtures are often used det, the proportion of 50 to 90 wt .-% of the monoalkylated Have product, for example Dowfax® 2A1 (trademark of Dow Chemical Company). The compounds II are generally be knows, e.g. B. from US-A 4,269,749, and commercially available.

The compounds I and / or are preferred whose salts with anionic and / or non-anionic auxiliary dis Combining agents. Remarkably, this one Connection an inhibitory effect of the Ver bindings I on the foam-promoting effect of Auxiliary dispersants are found.

The content of dispersant (compounds and / or salts of the general formula I and auxiliary dispersant) is in the range from 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the amount of polymer dispersed. The share of connections gene and / or salts of general formula I on the dispersant is at least 20% by weight, but often not more than 80 wt .-% and usually 20 to 60 wt .-%. The share can also be up to 100 wt .-%.

Radically polymerizable monomers come in particular monoethylenically unsaturated monomers, for example Olefins with up to 4 carbon atoms such as ethylene, vinyl aromatic mono mers with up to 10 carbon atoms such as styrene, α-methylstyrene, ortho-chlorostyrene or vinyl toluenes, vinyl and vinylidene halides, such as vinyl and vinylidene chloride, vinyl esters of C₁-C₁₈ monocarbon acids such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate and vinyl stearate, esters of preferably 3 to 6 carbon atoms having α, β-monoethylenically unsaturated mono- and dicarbon acids, such as in particular acrylic acid, methacrylic acid, maleic acid, Fumaric acid and itaconic acid with generally 1 to 12, preferred have 1 to 8 and in particular 1 to 4 carbon atoms Alkanols, in particular acrylic acid and methyl methacrylate, ethyl, n-butyl and -2-ethylhexyl esters, dimethyl maleate ester or maleic acid di-n-butyl ester. There are also nitriles mentioned α, β-monoethylenically unsaturated carboxylic acids, such as Acrylonitrile or methacrylonitrile and conjugated dienes with 4  up to 8 carbon atoms, e.g. B. 1,3-butadiene or isoprene. In In many cases, it has proven beneficial if the share of the nitriles in the total amount of the monomers used is smaller than 15% by weight, preferably 0% by weight.

The monomers mentioned are essentially in an aqueous medium insoluble and usually form the main monomers that based on the total amount of monomers used, more normal have a share of more than 70% by weight.

Furthermore, the polymers can modify up to 30% by weight or contain crosslinked monomers in copolymerized form. To the modifying monomers include those monomers that stand alone Usually polymerizes water-soluble homopolymers ben. They are usually up to 15% by weight, preferably 1 up to 10% by weight. Examples of such mono mers are α, β-monoethylenically unsaturated mono- and dicarboxylic acids ren and their amides, such as. As acrylic acid, methacrylic acid, malein acid, fumaric acid, itaconic acid, acrylamide and methacrylamide, also vinylsulfonic acids and their water-soluble salts, vinyl phosphonic acids, their salts and their esters with C₁-C₄ alkanols as well as N-vinylpyrrolidone and 2-hydroxyethyl acrylate, 3-hydroxy propyl acrylate or dimethylaminoethyl acrylate.

Crosslinking monomers can be used in amounts of up to % By weight, preferably from 0.5 to 10% by weight, in particular from 1 up to 6 wt .-%, based on the total amount of mono used meren, such monomers are used that only during the Drying of the polymer undergo the crosslinking reaction, wherein the crosslinking reaction by annealing and optionally by adding catalysts, such as. B. proton-releasing Substances such as maleic acid, diammonium hydrogen phosphate or Ammonium nitrate, can be forced. Examples of such mono mers are N-alkylolamides of α, β-monoethylenically unsaturated Carboxylic acids with 3 to 10 carbon atoms, including N-ethylol acrylamide and N-methylol methacrylamide are preferred. As networked the monomer with a reactive effect are acrylamidoglycolic acid and Methacrylamidoglycolic acid and its ethers, esters or ether esters with C₁-C₁₂ alkanols, for example acrylamidomethoxyacetic acid, Acrylamidohydroxyacetic acid methyl ester, Acrylamidomethoxyessig Acid methyl ester, methacrylamidomethoxyacetic acid, methacrylic amidohydroxyacetic acid methyl ester, methacrylamidomethoxyacetic acid acid methyl ester, the corresponding butyl and butoxy derivatives, Butyl acrylamidobutoxyacetate and methacrylamidobutoxy butyl acetate particularly preferred. Furthermore, the Ammonium salts of the (meth) acrylamido acids mentioned are suitable. These crosslinking systems split during the crosslinking reaction  no toxicologically questionable formaldehyde. The free (Meth) acrylamidoglycolic acid is very particularly preferred.

The choice of the monomer composition within the abovementioned composition grid is often such that the glass transition temperature (T _G values; DSC, mid-point temperature) of the resulting dispersed polymers is below 40 ° C. or below 30 ° C., often below 20 ° C and often below 0 ° C (down to -70 ° C).

The emulsion polymerization is advantageously carried out after a Inlet procedure, including step or gradient operation, carried out. The feed process in which one is preferred Part of the polymerization approach submitted to the polymer heated to temperature, polymerized and then the rest of the monomers and emulsifiers and the rest of the polymerization initiators continuously via separate feeds to the reaction approach feeds. Here one proceeds in such a way that one prefers above 70% by weight, particularly preferably above 80% by weight and very particularly preferably above 90% by weight of the total amount Monomer according to the progress of the polymerization already in the Monomers located in the polymerization vessel (both pure mono merenzulauf and preemul as a macro emulsion in the aqueous phase yaw) so that at least 80 wt .-%, preferably at least 90 wt .-% and particularly preferably at least 95 wt .-% of the Polymerized monomers located polymerized are. To influence the particle size of the dispersed poly Merisate particles can polymerize in the presence of aqueous Seed polymer dispersions are carried out (cf. EP-B 40 419 and Encyclopedia of Polymer Science and Technology, Vol. 5, John Wiley & Sons Inc., New York (1966) p. 847).

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 peroxide sulfates, ammonium peroxide sulfate or H₂O₂, as well as azo compounds.

Combined systems consisting of at least one are also suitable organic reducing agent and at least one peroxide and / or Hydroperoxide are composed, e.g. B. tert-butylhydro peroxide and sodium hydroxymethanesulfinate or hydrogen peroxide and ascorbic acid. Combined systems are also suitable in addition, a small amount of one in the polymerization medium soluble metal compound, the metallic component in meh reren valency levels can occur, contain, for. B. Ascorbin acid / iron (II) sulfate / hydrogen peroxide, instead of  Ascorbic acid also commonly sodium hydroxymethanesulfinate, sodium sulfite, sodium bisulfite or sodium bisulfite and instead of hydrogen peroxide tert-butyl hydroperoxide or alkali metal peroxidisulfate and / or ammonium peroxidisulfate who applied the. As a rule, the amount of radicals used is rule initiator systems, based on the total amount of poly merizing monomers 0.1 to 2 wt .-%. Particularly preferred are used as initiators ammonium and / or alkali metal peroxides sulfates used by themselves or as a component of combined systems puts.

The radical aqueous emulsion polymerization can be given if performed in the presence of regulators. Suitable Regulators are, for example, mercapto compounds, such as mercapto ethanol, mercaptopropanol, mercaptobutanol, mercaptoacetic acid, Mercaptopropionic acid, butyl mercaptan and dodecyl mercaptan. As Regulators are also suitable for allyl compounds such as allyl alcohol. If the reaction is carried out in the presence of regulators, can be 0.05 to 20 wt .-%, based on the poly used monomers.

The polymerization temperature is usually 30 to 95 ° C, preferably 75 to 90 ° C. The polymerization medium can both only from water, as well as from mixtures of water and thus miscible liquids such as methanol exist. Preferably only water is used.

The application of increased or reduced pressure is possible so that the polymerization temperature also exceed 95 ° C and up to be 130 ° C or more. Preferably, they are easily cursed term monomers such as ethylene, butadiene or vinyl chloride polymerized under increased pressure.

The polymer content of the aqueous polymer dispersions obtained be carries at least 10 vol .-%, based on the polymer dispersion. It is expediently in the range from 20 to 75% by volume.

Customary additives can be added to the polymer dispersions will. They are usually added after the end of the polymerization give. Crosslinking non-polymerizing are mentioned bare substances, usually in amounts of 0.1 to 5 wt .-% can be present. If the polymer contains free carboxyl groups, are suitable compounds that can crosslink such groups such as basic compounds of polyvalent metals, e.g. B. zinc oxide, Calcium oxide or the corresponding hydroxides, acetates or Carbonates or the corresponding mixed salts. Farther connections are suitable, the existing ones  Crosslink hydroxy groups. These include difunctional and polyfunctional ones inorganic acids and acid derivatives, e.g. B. phosphorus oxychloride, Alkali trimetaphosphates, alkali polyphosphates or alkali tetra borate, di- and polyfunctional organic acids, e.g. B. Adipin acid, citric acid, 1,2,3,4-butanetetracarboxylic acid, all-cis-1,2,3,4-cyclopentanetetracarboxylic acid. These continue to count Derivatives of di- and polyfunctional organic acids, such as Anhydrides or mixed anhydrides, e.g. B. diacetyladipic acid, Acetyl citric anhydride, acid chlorides, e.g. B. cyanuric acid chloride, imidazolides and guanidine derivatives. In addition, di and polyfunctional isocyanates such as hexamethylene diisocyanate, Toluene-2,4-diisocyanate toluene, di- and polyfunctional alkyl means, e.g. B. epichlorohydrin, β, β'-dichloroethyl ether, Diepoxides, various aldehydes or aldehyde derivatives such as form aldehyde, acetaldehyde, acrolein, 2,5-dimethoxytetrahydrofuran or Suitable for glutardialdehyde. Condensation products also occur based on formaldehyde, glyoxal, melamine, phenol and / or urine material into consideration. Here are formaldehyde and formaldehyde crosslinker systems due to toxicological concerns suitable.

The usual for bonded fiber composites (nonwovens) Additives can be added in known amounts, whereby biodegradable substances are preferred. To get the The product properties are the bonded fiber composite materials often free of clay or chalk.

Fibers are used for the fiber composites according to the invention costume that are biodegradable. In general it is about are natural fibers such as cellulose fibers, e.g. B. Tree wool, bast, cellulose, modified natural fibers, e.g. B. Vis cos fibers, acetate fibers or synthetic fibers such as aliphati cal polyester fibers, for example based on polymers and copolymers of 3-hydroxybutyrate, 3-hydroxyvalerate and 4-hydroxyvalerate as described in EP-A 466050. In egg In a preferred embodiment, the fibers have a diameter water from 0.002 to 0.1 mm, preferably 0.01 to 0.05 mm, wherein the diameter in the usual way with the help of electron micros copied recordings can be determined. The formation of fiber Nonwovens made from the fibers are generally known (Römpp, Chemie Lexi kon, Georg-Thieme-Verlag, Stuttgart-New York, 9th edition, p. 4550). It can be tangled nonwovens or preferably ge straightened non-woven fabrics with or without mechanical pre-consolidation, act, for example, by needling, swirling or sewing. (see also Ullmann’s Encyclopedia of Chemical Engineering, 4. Edition, volume 23, 1983, p. 733 ff.)  

The consolidation of the nonwovens with the polymers to the Fiber composite materials according to the invention are made according to known Methods (e.g. Ullmann’s encyclopedia of technical chemistry, 4th edition, volume 23, 1983, pp. 738 to 742). Usually the fiber fleece by bath impregnation, foam impregnation, spraying hen, splashing or printing with the polymer dispersion soaks. For this purpose the dispersion may be diluted with water or be thickened with conventional thickeners to get the desired set processing viscosity. The fleece treatment the dispersion is generally followed by drying and tempering of the fiber composite obtained. The drying conditions depend on the type of dryer used, The drying temperature is usually between 100 and 230 ° C and the drying or tempering is between 10 seconds and 60 min.

The proportion of polymer (a) based on the unbound fibers (b) in the finished fiber composite is in the range of 20: 1 to 1: 2 (parts by weight b: a, based on the solids content of the Polymer dispersion), preferably in the range from 10: 1 to 1: 1, be particularly preferably in the range from 5: 1 to 2: 1.

The fiber composite materials according to the invention are notable for their good compostability with favorable usage properties out. You assign u. a. good dry strength, high wetness strength and a soft grip.

The following examples are intended to illustrate the present Illustrate the invention without restricting it.

Examples

A partially hydrolyzed lecithin (Lipo tin® NE, from Lucas Meyer GmbH & Co., Hamburg).

Micronize lecithin

50 g Lipotin® NE were at 25 ° C using a dispersing stirrer (Ultra-Turrax, IKA, Stauffen) micronized in 200 g of water (9000 rpm, 5 min.). An aqueous dispersion (micro nisat) of the Lipotin® NE. The average particle size was 217 nm (As the particle diameter are below, if nothing else is always mentioned the Z mean, determined by photon cores Relation spectroscopy using an Autosizer 2C from Mal vern Instruments, England).  

Preparation of the polymer dispersions example 1

In a glass reactor with stirrer, reflux condenser, gas inlet and a mixture of two separate feeds

23.7 g polystyrene seed dispersion (solids content: 35% by weight,
Particle size: 38 nanometers, stabilized with 10% by weight (based on the solids content) of dodecyl benzenesulfonic acid sodium salt
0.89 g Dowfax® 2A1 (aqueous solution containing 45% by weight solids)
2% by weight of feed 1
20% by weight of feed 2
400 g of demineralized water

submitted. The template was stirred within 15 min. on Heated 85 ° C and then 10 min. with stirring at this Temperature maintained. It was then maintained the temperature, the remaining amount of feed 1 within 3 h and the Remaining amount of feed 2 within 3.5 h (starting simultaneously) continuously metered into the polymerization vessel with stirring.

The mixture was then stirred at 85 ° C for a further 2.5 h. You got an aqueous polymer dispersion D 1 with a polymer volume content of 45.9% by volume. The average polymer particle diameter was 222 nm.

Inlet 1:
Aqueous emulsion
400 g styrene
376 g of n-butyl acrylate
24 g acrylamide
40 g lecithin micronisate
0.89 g Dowfax® 2A1
352 g of demineralized water

Inlet 2:
3.2 g sodium peroxysulfate
100 g demineralized water.

Example 2 (Comparative example)

The procedure was as in Example 1, in contrast to Bei In game 1, feed 1 contained no micronized lecithin.

It was an aqueous polymer dispersion D₂ with a polymer volume amount of 45.8 vol% obtained. The average particle diameter it was 204 nm.  

Example 3 (Comparative example)

The procedure was as in one of the aforementioned examples. The Submission consisted of

23.7 g polystyrene seed dispersion (see above)
2.0 g of sodium lauryl sulfate (aqueous solution with a% by weight solids content)
2% by weight of feed 1
20% by weight of feed 2
400 g of deionized water

Inlet 1:
Aqueous emulsion
400 g styrene
376 g of n-butyl acrylate
24 g acrylamide
20 g sodium lauryl sulfate solution (see above)
352 g of demineralized water

Inlet 2: see example 1.

It was an aqueous polymer dispersion D₃ with a polymer volume amount of 46.8 vol% obtained. The average particle diameter water was 188 nm.

Example 4 (Comparative example)

The procedure was as in Example 1.

Template:
23.7 g polystyrene seed dispersion (see above)
1.3 g potassium oleate solution (aqueous solution with
23% by weight solids content)
2% by weight of feed 1
20% by weight of feed 2
400 g of demineralized water

Inlet 1:
Aqueous emulsion
400 g styrene
376 g of n-butyl acrylate
24 g acrylamide
13 g potassium oleate solution (see above)
352 g of demineralized water

Inlet 2: see example 1.

It was an aqueous polymer dispersion D₄ with a polymer volume amount of 46.2 vol% obtained. The middle polymer particle diameter was 188 nm.

Production of the fiber composite materials according to the invention

A longitudinal (fiber orientation preferred in the longitudinal direction raw) viscose fleece (100% biodegradable, Dilo) with a Weight of 67 g / m² was determined in independent tests with the Dispersions of Examples 1 to 4, previously based on one unit Liche solids content of 10 wt .-% had been diluted soaks, to separate the excess dispersion between brought two opposing rollers and then 4 min. exposed to a temperature of 150 ° C. The binder content of the Fiber composites thus obtained was in all cases 25% by weight.

Investigations on the bonded nonwovens

Strips 50 mm wide were cut from the nonwovens this with a free clamping length of 10 cm in a dry condition was used to determine the tensile strength in analogy to DIN 53 857 subjected to a patrol test. The tear resistance became cross-cutting (by cutting the test specimen accordingly) measured to the preferred fiber direction. The results of these experiments are shown in Table 1.

Composting the nonwovens

The compostability of the nonwovens obtained was determined using an earth digging test based on DIN 52933 was examined. For this purpose, several samples each with the polymer dis persions of Examples 1 to 4 consolidated nonwovens together with several samples of an unconsolidated nonwoven fabric as a con trolleys (slightly pre-needled viscose fleece with a flat surface weight of 67 g / m²) buried in potting soil. The earth moisture of the Potting soil was approximately 200% by weight, the test temperature was 30 ° C. The Nonwovens were dug up as soon as the tensile strength drop of the unbound fleece was 90% (after about 5 to 10 days). On the tensile strength of the samples was then determined. Of the Loss of tear strength was used as a measure of compostability used. In addition, the nonwoven fabric samples were visually examined assessed their state of decay.  

Table 1

Tear resistance of nonwovens

Table 1 shows that the reduction in tear strength solidified with a lecithin-containing polymer dispersion Nonwoven fabric is significantly larger than that with lecithin-free Polymer dispersions consolidated nonwovens. That is, the one with a polymer dispersion treated with phospholipids fiber ver Bund materials are compostable and essentially rot as fast as untreated, compostable fiber composite fabrics. The tensile strength of the fiber composite materials is determined by treatment with a polymer dispersion with phospholipids not significantly affected.

Claims (16)

  1. Use of aqueous polymer dispersions, at least contain a natural or synthetic phospholipid, for the production of compostable fiber composites. 2. Use according to claim 1, wherein the polymer dispersion as phospholipid at least one compound of the general formula I, wherein
R¹ for the acyl residue of an aliphatic C₈-C₂₆-carboxylic acid, the acyl residue of a mono- or polyunsaturated aliphatic C₈-C₂₆-monocarboxylic acid, or the acyl residue of a C₈-C₂₆-monocarboxylic acid, which consists of the corresponding mono- or polyunsaturated aliphatic monocarboxylic acid partial or complete hydroxylation of the unsaturated functions is available,
R² and R³ independently of one another for H, CH₂-CH₂-O _m H with m = 1 to 50, -SO₃H, -PO₂H₂, an acyl radical such as R¹ or stand,
R⁴ is C₁-C₅ alkyl, with the proviso that either R² or R³ is stands,
and / or contains a salt of a compound of general formula I. 3. Use according to claim 2, wherein R¹ in the general For mel I has an even number of carbon atoms. 4. Use according to claim 2 or 3, wherein R¹ in general NEN Formula I 12 to 24 and in particular 14 to 22 carbon atoms having. 5. Use according to claim 2, wherein R¹ is one for the acyl radical Carboxylic acid, which is selected from palmitic acid, Stearic acid, oleic acid, linoleic acid, linolenic acid, palmitolein acid and arachidonic acid. 6. Use according to any one of claims 2 to 5, wherein R² or R³ in the general formula I represents a hydrogen atom. 7. Use according to any one of claims 2 to 6, wherein R² or R³ for stands,
where Z for
CH₂-CH₂N⊕ (CH₃) ₃⊖OH,
CH₂-CH₂NH₂ or
C₆H₆ (OH) ₅ stands. 8. The method according to any one of the preceding claims, wherein the
Polymer content of the dispersion is at least 10% by volume, based on the aqueous polymer dispersion. 9. Use according to any one of the preceding claims, wherein the polymer dispersion 0.1 to 10% by weight of dispersant, based on the dispersed polymer. 10. Use according to claim 9, wherein the dispersant we at least 20% by weight of a compound of general formula I. and / or their salts. 11. Use according to one of the preceding claims, wherein the polymer dispersion by radical emulsion polymerisa tion of at least one ethylenically unsaturated monomer, which has at least one C = C double bond in an aq medium is available. 12. Use according to any one of the preceding claims, wherein the polymer too 70 to 100% by weight of a C₁-C₁₂ acrylic acid ester, C₁-C₁₂ methacrylic acid ester, styrene, butadiene, vinyl acetate and / or Vinyl propionate is built up. 13. Use according to any one of the preceding claims, wherein the number average polymer particle diameter of the aqueous Polymer dispersion is in the range of 150 nm to 800 nm. 14. Fiber composite materials from biodegradable fibers, in which the fibers with a binder according to one of the Claims 1 to 13 are solidified, the quantitative ratio nis fiber / binder in the range of 20: 1 to 1: 2 (weight proportions based on the solids content of the binder), is preferably in the range from 10: 1 to 1: 1. 15. Fiber composite materials according to claim 14, wherein the fibers are selected from cellulose fibers, viscose fibers or Polyester fibers based on 3-hydroxy polymers butyric acid, 3-hydroxyvaleric acid and / or 4-hydroxyvale rian acid. 16. Fiber composite materials according to one of claims 14 or 15, the fibers having a diameter in the range of 0.002 to 0.1 mm.