EP1913083A1 - Use of a thermally curable aqueous composition as a binder for substrates - Google Patents

Abstract

The present invention relates to the use of a thermally curable aqueous composition comprising dispersed polymer particles of at least a) one polymer A1 containing 98-100% by weight of ethylenically unsaturated monomers A, where up to 20% by weight of the monomers A may contain glycidyl and/or hydroxyl groups and/or amine/amide groups and the polymer contains ≤ 5% by weight of an α,β-ethylenically unsaturated mono- or dicarboxylic acid and at least 1% by weight of acrylonitrile in copolymerized form, and 0-5% by weight of a bi- or multifunctional monomer, and b) one polymer A2 which is soluble in serum and contains, in copolymerized form, 60-100% by weight of at least one α,β-ethylenically unsaturated mono- or dicarboxylic acid whose carboxylic acid groups may form an anhydride group, salts or mixtures thereof, c) and a polyfunctional crosslinker or mixtures thereof, d) and optionally di- or trivalent metal ions which are added in the form of hydroxides, oxides, carbonates or hydrogencarbonates, as binders for substrates.

Description

Use of a thermally curable aqueous composition as a binder for substrates

description

The present invention relates to the use of formaldehyde-free thermally curable aqueous compositions as binders for substrates, in particular as binders for the production of bonded nonwovens. Another object of the invention is a process for the preparation of the binder.

Solidification of nonwovens can be done mechanically by calendering or needling. In order to achieve a sufficient heat resistance, the mechanical solidification is not sufficient. A substantial improvement in the heat resistance is achieved by solidification with chemical binders, which are applied in the usual way, for example in the form of aqueous polymer dispersions on the nonwoven fabric.

To increase the strength, in particular the wet strength and heat resistance, binders are often used which contain formaldehyde-releasing components. This poses the problem of formaldehyde emissions during application and end use. Such aqueous polymer dispersions used as binders usually contain a high degree of N-methylol groups in order to ensure good heat resistance of the polymer film and thus also of the bonded nonwoven fabric. The N-methylol groups form covalent crosslink bonds to hydroxyl or amide groups of the binder or fiber of the fabric.

In order to achieve greater crosslinking, such binders are sometimes added in the aqueous phase to soluble polymers such as water-soluble aminoplast resins. For example, US Pat. No. 4,125,663 describes such a polymer dispersion to which N-methylol groups are added as urea or melamine-formaldehyde resins to the dispersion. Compounds such as e.g. N-methylolacrylamide or N-methylolmethacrylamide can also be copolymerized directly into the dispersion (US Pat. No. 3,137,589).

As further monomers, for example, acrylonitrile, methyl methacrylate, acrylic acid, methacrylic acid, maleic acid, acrylamide or styrene and monomers which, in contrast to the above, have a low glass transition temperature in the polymer film used. Other such relatively low glass transition temperature monomers include butadiene, isoprene or chloroprene. Such sammengesetzte to-N-methylol-containing dispersion polymers typically have glass transition temperatures of at least 10 ⁰ C, but in general from 20 ⁰ C to 40 ° C. Binders whose glass transition temperatures are in this range have the disadvantage of imparting high stiffness and hardness to the bonded nonwoven fabrics, which can lead to difficulties in processing at low temperatures.

To produce the bonded nonwoven fabrics is dried after application of the N-methylol-containing dispersion at temperatures of 130 ⁰ C, but often at above 150 ⁰ C, wherein a filming and crosslinking of the polymer takes place. A disadvantage of the binders containing N-methylol groups, as mentioned above, is that considerable amounts of formaldehyde are liberated during drying and are removed with the dry air. The N-methylol groups give the film and thus also the nonwoven a good heat resistance, which is lost when using N-methylol-free binders.

To avoid formaldehyde emissions, numerous alternatives have already been proposed to the binder systems known hitherto:

Thus, e.g. N-methylolacrylamide or N-methylolmethacrylamide be replaced by non-formaldehyde releasing crosslinkers such as acrylamidoglycolic acid (EP 19169, EP 326298), N- (butoxymethyl) acrylamide (WO 92/08835).

Another formaldehyde-free alternative is the metal salt crosslinking of polymers.

For example, DE 4004915 and DE 196 19 639 describe binders based on metal salt crosslinking, inter alia. for nonwovens. Since they are ionomers, the water resistance is often unsatisfactory and the crosslink density is temperature dependent. Consequently, they may need to be blended with aminoplast or resorcinol resins to achieve desired heat and water resistance.

US Pat. No. 3,404,116 and GB 1239902 each describe dispersion polymers based on hydroxyl-containing copolymerizable monomers which are suitable as binders for paper, nonwoven webs and similar nonwovens. Only a good softness, flexibility and moisture resistance should be achieved. The problem of high heat resistance is not addressed.

EP 345 566 describes water-dispersed binders for nonwovens which contain hydroxyalkylated copolymers and are thermally crosslinked with water-soluble, formaldehyde-free imidazolidone derivatives.

US 20020187270 describes thermally curable binders based on an emulsion polymer which contains carboxyl and acetoacetoxy groups and is crosslinked by admixture with polyaldehyde and polyaziridine derivatives. EP 392 353 describes thermally curable binders for nonwovens of nonwoven fabrics based on emulsion polymers which contain no further polymerisable groups or groups which can be condensed with one another, and a water-soluble polymer which is essentially composed of N-hydroxy-carboxymethylamides of acrylic and / or methacrylic acid ,

From US Pat. No. 4,076,917 binders are known which contain carboxylic acid- or carboxylic anhydride-containing polymers and .beta.-hydroxyalkylamides as crosslinkers. A disadvantage is the relatively complicated preparation of the β-hydroxyalkylamides.

Thermally curable binders of polycarboxylic acids and polyols or alkanolamines are e.g. from EP 445 578, EP 583 086, EP 651 088, EP 672 920, EP 882 074, EP 882 003 or DE 199 49 592.

No. 5,314,943 describes a low-viscosity fast-curing binder for textile substrates, which is a mixture of an aqueous emulsion copolymer latex with an aqueous solution copolymer. The aqueous solution copolymer is obtained by copolymerization of an α, β-ethylenically unsaturated monocarboxylic acid and an α, β-ethylenically unsaturated dicarboxylic acid. The emulsion copolymer latex contains units of monomers selected from alkenylaromatic, conjugated diolefins, vinyl acetate and acrylates.

US 4,868,016 discloses a composition based on at least one thermoplastic, aqueous alkaline medium insoluble latex polymer and at least one alkali soluble polymer which is incompatible with the latex polymer. The latex polymer is a water-dispersed polymer which may be composed of acrylic or methacrylic acid esters, vinylaromatic compounds and vinyl esters and additionally contains 0.5 to 3% by weight of an ethylenically unsaturated carboxylic acid in copolymerized form. The alkali-soluble polymer is also composed of the stated monomers, but contains 10 to 60% by weight of an ethylenically unsaturated carboxylic acid. To adjust the pH to> 7, the composition may contain ammonia, triethylamine, ethylamine or dimethylhydroxyethylamine. It is useful for coating substrates.

EP 537 910 discloses mixtures of emulsion polymers, which are preferably composed of styrene and n-butyl acrylate, with acid-rich, water-soluble polymers which, when used as binders for paints, should lead to coatings with good substrate wetting and high solvent resistance.

EP 1 018 523 describes polymer dispersions which, in addition to the dispersed polymer particles in the serum, contain water-soluble polycarboxylic acids and an alkoxy- lated long-chain amine and polyfunctional alcohols which can be used as thermally curable binders for fabrics and moldings.

In DE 10151569, thermally curable binders based on an emulsion polymer, an acid polymer and an epoxy compound are described as curing agents. In addition, an alkanolamine can be used as a hardener in addition to the epoxide.

In WO 99/09100 aqueous compositions are described which contain an acid-rich, a low-acid polymer component and an alkanolamine having at least two hydroxyl groups and can be used as thermally curable binders for moldings.

U.S. 4,670,505 discloses a polyacrylate dispersion prepared by emulsion polymerization in the presence of 0.05 to 5% by weight of a protective colloid, e.g. Polyacrylic acid or its alkali metal salts, and 0.1 to 5 wt .-% of a water-soluble amino alcohol having 2 to 36 carbon atoms is produced. The dispersion obtained has a low viscosity, a good pigment binding capacity and is essentially free of specks and shear stable. For higher amounts of polyacrylic acid, the composition should show a very high viscosity, which may be used as a binder, e.g. for fibrous substrates.

EP 1 240 205 describes a thermally curable binder based on an emulsion polymer which is prepared in the presence of a carboxyl-containing polymer.

In many applications of bonded nonwovens, in particular based on polyester fiber, carbon fiber or glass fiber nonwovens a very good heat resistance and tear strength at room temperature of the bonded nonwoven fabric is required at the same time low water absorption capacity. So far, this property could only be achieved by bonded nonwovens with N-methylol-containing binders. In the case of the formaldehyde-free binders which have hitherto been described in the prior art, insufficient tear strengths and / or excessively high water absorption capacity are observed in the case of good heat resistance. In addition, colloidal stability problems or phase separations are observed in the case of mixtures of several components, in particular colloid-polymer mixtures. This topic is extensively used in textbooks on colloid chemistry / physics, such as Evans and Wennerström's "The Colloidal Domain" VCH, 1994, discussed.

Compared to the previously known thermally curable binders, the object of the present invention was a non-formaldehyde-emitting, thermal to provide curable binder for substrates such as mats or plates, in particular for the production of bonded nonwovens available.

The object has been achieved according to the invention by the use of a thermally curable aqueous composition containing dispersed polymer particles at least

a) containing a polymer A1,

98-100 wt .-% of ethylenically unsaturated monomers A, wherein up to 20 wt .-% of the monomers A glycidyl and / or hydroxyl groups and / or amine / amide groups may contain and the polymer <5 wt .-% of a α, ß-ethylenically unsaturated mono- or dicarboxylic acid and at least 1 wt .-% acrylonitrile in copolymerized form, and 0-5 wt .-% of a bifunctional or multifunctional monomer and b) a soluble in serum polymer A2, which in polymerized form 60 100% by weight of at least one α, β-ethylenically unsaturated mono- or dicarboxylic acid whose carboxylic acid groups can form an anhydride group, salts or mixtures thereof contains c) and a polyfunctional crosslinker or mixtures thereof d) and optionally divalent or trivalent metal ions which in the form of

Hydroxides, oxides, carbonates or bicarbonates may be added

as a binder for substrates.

The aqueous composition is prepared by free-radical emulsion polymerization of polymer A1 in the presence of a polymer A2 and / or admixing of the polymer A2 to the emulsion polymer A1, and optionally subsequent addition of divalent or trivalent metal ions in the form of hydroxides, oxides, carbonates or bicarbonates and / or or fillers

The binders according to the invention are used, for example, as nonwovens for cleaning and wiping cloths, filter materials, as wallpaper carrier webs, in bituminized roofing membranes, binders for natural fibers or as inliners or carrier material for floor coverings, such as e.g. made of PVC.

They are, inter alia, suitable for improving the strength of the molded articles obtained therefrom, in particular the heat resistance and water resistance at comparatively high tear strengths in comparison to the binder systems used hitherto. The binder according to the invention preferably has a high colloid stability and / or a low viscosity at high solids content. The binder should be dilutable with water or dilute salt or surfactant solutions as unlimited as possible. It can be assumed that the system is present in a colloidal 2 or multi-phase system after synthesis and also after dilution to liquor concentration (depletion separation). Regardless of the number of colloidal phases, the system should have the required performance properties after impregnation and drying.

The domain size of the phases may be under shear in the μm to mm range, i. If they separate macroscopically, the phases can be "homogenized" by stirring again.

Accordingly, the bonded nonwoven fabrics described above were found. The invention further provides a process for their preparation and their use as cleaning and wiping cloths, as wallpaper backing web, for roofing membranes, as a filter material, natural fiber molded articles and a manufacturing method for cleaning and wiping cloths, for wallpaper backing webs, for roofing membranes, for filter materials, for natural fiber molded articles.

The binders of the invention generally have a content of non-volatile constituents (solids content) of 10 to 70 wt .-%, preferably 25 to 55 wt .-%, particularly preferably 40 to 55 wt .-% to. The viscosity of the binders of the invention is at a solids content of about 50 wt .-% in the range of 10 to 2000 mPas, preferably from 30 to 1000 mPas, measured with a rotational viscometer according to DIN 53019 at 23 ⁰ C and a shear rate of 250 s ^-1 ,

The colloidal system (dispersed particles / water-soluble polymer / dispersion medium water) can be both homogeneous (single-phase) and multi-phase (depletion separation) after preparation and / or application (impregnation) or in the solids content range from 0.1 to 70 wt .-% , The serum-soluble polymers may be partially or completely grafted onto the dispersed particles by chemical bonding and / or physical adsorption.

The solids-based weight ratio of the dispersed particles to dissolved serum components is in the range of 9: 1 to 1: 9, preferably 4: 6 to 6: 4, more preferably 1: 1. The weight ratio of dissolved and grafted polymer to polyfunctional crosslinker ranges from 20: 1 to 2: 1. The metal ion content is 0 to 110 mol%, based on the polymerized α, ß-ethylenically unsaturated mono- or dicarboxylic acid or its salts.

The filler content is 0 to 70 wt .-% based on the polymeric portions of the aqueous composition The glass transition temperature of the dispersed particles is in the range of T _G = -30 to 110 ⁰ C and the average particle diameter (numbers middle I) in the range of 50 to 400 nm. There may be both a mono- and a multimodal particle size distribution.

The aqueous binder can be obtained by mixing the polymer A1 with dissolved polymer A2, the polyfunctional crosslinker and optionally the metal salts and / or fillers. Either the polymer A1 or the polymer A2 can be initially charged. The mixing can be carried out by mixing techniques, for example in a stirred tank, in a static or dynamic mixer.

Furthermore, the preparation of the binder can also be carried out by free-radical emulsion polymerization of the polymer A1 with the polymer A2.

In the context of the monomer components of the polymer A1, alkyl in the following preferably represents straight-chain or branched C ₁ -C 2 -alkyl radicals, in particular C ₁ -C 12 -alkyl and particularly preferably C ₁ -C 6 -alkyl radicals, such as methyl, ethyl, n-propyl, n- Butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-dodecyl or n-stearyl. Hydroxyalkyl is preferably hydroxy-C 1 -C 6 -alkyl, where the alkyl radicals may be straight-chain or branched, and in particular 2-hydroxyethyl, 2- or 3-hydroxypropyl, 2-methyl-2-hydroxypropyl and 4-hydroxybutyl , Cycloalkyl is preferably Cs-CyCyclohexyl, in particular cyclopentyl and cyclohexyl.

Aryl is preferably phenyl or naphthyl.

The polymer A1 represents a free-radical emulsion polymer. For the preparation thereof, it is possible to use all monomers which can be polymerized by free-radical polymerization. In general, the polymer is composed of

From 80 to 100% by weight, preferably from 85 to 99.9% by weight, based on the total weight of the monomers for the polymer, of at least one main ethylenically unsaturated monomer and

0 to 20 wt .-%, preferably 0.1 to 15 wt .-%, based on the total weight of the monomers for the polymer, at least one ethylenically unsaturated

Comonomers.

The main monomer is preferably selected from

Esters of preferably 3 to 6 carbon atoms having α, β-monoethylenically unsaturated mono- or dicarboxylic acid, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid with Ci-Ci ₂ -, preferably Ci-C ₈ - Alkanols. Such esters are in particular methyl, ethyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl and 2-ethylhexyl acrylate and / or methacrylate;

vinyl aromatic compounds, preferably styrene, α-methylstyrene, o-chlorostyrene, vinyltoluenes and mixtures thereof;

Vinyl esters of Ci-Cie mono- or dicarboxylic acids, such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate and / or vinyl stearate;

- butadiene;

linear 1-olefins, branched-chain 1-olefins or cyclic olefins, such as. Ethene, propene, butene, isobutene, pentene, cyclopentene, hexene or cyclohexene. Furthermore, metallocene-catalyzed oligoolefins with terminal double bond, such as. B. Oligopropen or oligohexene suitable;

Acrylonitrile, methacrylonitrile;

- Vinyl and Allylalkylethem having 1 to 40 carbon atoms in the alkyl radical, wherein the alkyl radical may carry further substituents, such as one or more hydroxyl groups, one or more amino or diamino groups or one or more alkoxy lat groups, such. Methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether and 2-ethylhexyl vinyl ether, isobutyl vinyl ether, vinylcyclohexyl ether, vinyl 4-hydroxybutyl ether, decyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether,

(Diethylamino) ethyl vinyl ether, 2- (di-n-butyl-amino) ethyl vinyl ether, methyl diglycol vinyl ether and the corresponding allyl ethers or mixtures thereof.

Particularly preferred major monomers are styrene, methyl methacrylate, n-butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, ethene and butadiene.

The comonomer is preferably selected from

ethylenically unsaturated mono- or dicarboxylic acids or their anhydrides, preferably acrylic acid, methacrylic acid, methacrylic anhydride, maleic acid, maleic anhydride, fumaric acid and / or itaconic acid;

Acrylamides and alkyl-substituted acrylamides, such as. Acrylamide, methacrylamide, N, N-dimethylacrylamide, N-methylolmethacrylamide, N-tert-butylacrylamide, N-methylmethacrylamide and mixtures thereof; sulfo-containing monomers, such as. For example, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, allyloxybenzenesulfonic acid, their corresponding alkali metal or ammonium salts or mixtures thereof, and also sulfopropyl acrylate and / or sulfopropyl methacrylate;

Ci-C4-hydroxyalkyl esters of Cs-Cβ mono- or dicarboxylic acids, in particular of acrylic acid, methacrylic acid or maleic acid, or their with 2 to 50 moles of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof alkoxylated derivatives or esters of from 2 to 50 mol Ethylene oxide, propylene oxide, butylene oxide or mixtures thereof alkoxylated Ci-Cie alcohols with the mentioned acids, such as. B. Hydroxyethylacrylat, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, butanediol-1, 4-monoacrylate, ethyl diglycol acrylate, methyl polyglycol acrylate (11 EO), (meth) acrylic acid ester of reacted with 3,5,7,10 or 30 moles of ethylene oxide Ci3 / Ci5-oxo alcohol or mixtures thereof;

Vinylphosphonic acids and their salts, vinylphosphonic acid dimethylester and other phosphorus containing monomers;

Alkylaminoalkyl (meth) acrylates or alkylaminoalkyl (meth) acrylamides or their quaternization products, such as. B. 2- (N, N-dimethylamino) ethyl (meth) acrylate or 2- (N, N, N-trimethylammonium) ethyl methacrylate chloride, 3- (N ₁ N-dimethylamino) propyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylamide, 3-dimethylaminopropyl (meth) acrylamide, 3-trimethylammoniumpropyl (meth) acrylamide chloride and mixtures thereof;

Allyl esters of Ci-C ₃ o-monocarboxylic acids;

N-vinyl compounds, such as N-vinylformamide, N-vinyl-N-methylformamide, N-vinylpyrrolidone, N-vinylimidazole, 1-vinyl-2-methylimidazole, 1-vinyl-2-methylimidazoline, 2-vinylpyridine, 4-vinylpyridine, N-vinylcarbazole and / or N-vinylcaprolactam;

Diallyldimethylammonium chloride, vinylidene chloride, vinyl chloride, acrolein, methacrolein;

1, 3-diketo groups containing monomers, such as. Acetoacetoxyethyl (meth) acrylate or diacetone acrylamide, monomers containing urea groups, such as ureidoethyl (meth) acrylate, acrylamidoglycolic acid, methacrylamidoglycolate methyl ether; Silyl-containing monomers, such as. B. trimethoxysilylpropyl methacrylate;

Glycidyl-containing monomers, such as. B. glycidyl methacrylate.

Particularly preferred comonomers are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, glycidyl methacrylate, acrylamide, and mixtures thereof. Very particular preference is given to hydroxyethyl acrylate and hydroxyethyl methacrylate, glycidyl methacrylate, acrylamide, in particular in amounts of from 2 to 20% by weight, based on the total monomer A1.

By bi- or multifunctional monomers is meant compounds having two or more ethylenically unsaturated groups, such as, for example, diacrylates or dimethacrylates of at least bivalent saturated alcohols, such as. B. ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1, 2-propylene glycol diacrylate, 1, 2-propylene glycol dimethacrylate, butanediol-1, 4-diacrylate, butanediol-1, 4-dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, Neopentylglykoldiacrylat, Neopentylglykoldimethacry- lat, 3-methylpentanediol diacrylate and 3-methylpentanediol dimethacrylate. The acrylic acid and methacrylic acid esters of alcohols having more than 2 OH groups can also be used as crosslinking agents, eg. Trimethylolpropane triacrylate or trimethylolpropane trimethacrylate. Another class of bifunctional or multifunctional monomers are diacrylates or dimethacrylates of polyethylene glycols or polypropylene glycols having molecular weights of 200 to 9,000, respectively.

In addition to the homopolymers of ethylene oxide or propylene oxide can also

Block copolymers of ethylene oxide and propylene oxide or copolymers of ethylene oxide and propylene oxide are used, which contain the ethylene oxide and propylene oxide units randomly distributed. The oligomers of ethylene oxide or propylene oxide are suitable for the preparation of bi- or multifunctional monomers, z. B. diethylene glycol diacrylate, diethylene glycol dimethacrylate,

Triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate and / or tetraethylene glycol dimethacrylate.

Also suitable are vinyl acrylate, vinyl methacrylate, vinyl itaconate, dinitrile divinyl ether, butanediol divinyl ether, trimethylolpropane trivinyl ether, allyl acrylate, allyl methacrylate, pentaerythritol triallyl ether, triallyl sucrose, pentaallyl sucrose, pentaallylsucrose, methylenebis (meth) acrylamide, divinylethyleneurea, divinylpropyleneurea, di vinylbenzene, divinyldioxane, triallylcyanurate, tetraallylsilane, tetravinylsilane and bis- or polyacrylsiloxanes (eg Tegomere® from Th. Goldschmidt AG). The bi- or multi-functional monomers can be used in amounts of from 0 to 5% by weight, preferably in amounts of from 10 ppm to 5% by weight, based on the monomers to be polymerized. The polymer A2 contains from 50 to 99.5% by weight, preferably from 70 to 99% by weight, of those structural elements which are derived from at least one ethylenically unsaturated mono- or dicarboxylic acid. If desired, these acids may also be partially or completely present in the form of a salt in the polymer. The acidic form is preferred.

Preferably, the polymer A2 is more than 10 g / l (at 25 C) soluble in water.

Useful ethylenically unsaturated carboxylic acids have already been mentioned above in connection with the polymer A1. Preferred carboxylic acids are C3 to Cio monocarboxylic acids and C ₄ - to C ₈ dicarboxylic acids, especially acrylic acid, thacrylsäure metal, crotonic acid, fumaric acid, maleic acid, 2-methylmaleic acid and / or itaconic acid. Particularly preferred are acrylic acid, methacrylic acid, maleic acid and mixtures thereof. In the preparation of the polymer A2, it is of course also possible to use, instead of the acids or together with the acids, their anhydrides, such as maleic anhydride, acrylic acid or methacrylic anhydride.

The polymer A2 further contains 0 to 50 wt .-%, preferably 0 to 30 wt .-%, of at least one ethylenically unsaturated compound which is selected from the esters of ethylenically unsaturated monocarboxylic acids and the half-esters and diesters of ethylenically unsaturated dicarboxylic acids having at least one hydroxyl-containing amine, in copolymerized form.

The polymer A2 is preferably present as a comb polymer with covalently bound amine side chains.

Monocarboxylic acids suitable as a component of the esters are the abovementioned C3 to C10 monocarboxylic acids, in particular acrylic acid, methacrylic acid, crotonic acid, and mixtures thereof.

Dicarboxylic acids suitable as a component of the half-esters and diesters are the abovementioned C ₄ -C -dicarboxylic acids, in particular fumaric acid, maleic acid, 2-methylmaleic acid, itaconic acid, and mixtures thereof.

Preferably, the amine having at least one hydroxyl group is selected from secondary and tertiary amines having at least one Ce to C22 alkyl, Ce to C22 alkenyl, aryl Cβ to C22 alkyl or aryl Cβ to C22 Alkenyl group may have 1, 2 or 3 non-adjacent double bonds.

Preferably, the amine is hydroxyalkylated and / or alkoxylated. Alkoxylated amines preferably have one or two alkylene oxide radicals with terminal hydroxyl groups. groups on. The alkylene oxide radicals preferably have from 1 to 100, preferably from 1 to 50, identical or different alkylene oxide units, randomly distributed or in the form of blocks. Preferred alkylene oxides are ethylene oxide, propylene oxide and / or butylene oxide. Particularly preferred is ethylene oxide.

The polymer A2 preferably contains an unsaturated compound based on an amine component which comprises at least one amine of the general formula

R ^c NR ^a R ^b

contains, where

R ^{c represents} C ₆ - to C ₂ 2-alkyl, C ₆ - to C ₂ 2 -alkenyl, aryl-C ₆ -C ₂ 2 -alkyl or aryl-C ₆ -C ₂₂ -alkenyl, where the alkenyl radical 1, 2 or 3 may have non-adjacent double bonds,

R ^{a is} hydroxy-C ₁ -C ₆ -alkyl or a radical of the formula II

- (CH ₂ CH ₂ O) X (CH ₂ CH (CH ₃ ) O) _V -H (II)

where in formula II the sequence of the alkylene oxide units is arbitrary and x and y independently of one another are an integer from 0 to 100, preferably 0 to 50, where the sum of x and y is> 1,

R ^{b is} hydrogen, C ₁ - to C ₂₂ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, C ₆ - to C ₂₂ -alkenyl, aryl-C ₆ -C ₂₂ -alkyl, aryl-C ₆ -C ₂₂ -alkenyl or C ₅ - to C ₈ -cycloalkyl, where the alkenyl radical may have 1, 2 or 3 non-adjacent double bonds, or R ^{b is} a radical of the formula III

- (CH ₂ CH ₂ O) v (CH ₂ CH (CH ₃ ) O) _w -H (111)

in the formula IM, the sequence of the alkylene oxide units is arbitrary and v and w independently of one another are an integer from 0 to 100, preferably 0 to 50, stand.

Preferably, R ^{c is} Cs to C ₂ o-alkyl or Cs to C ₂ o-alkenyl, wherein the alkenyl radical 1, 2 or 3 may have non-adjacent double bonds. Preferably, R ^{c is} the hydrocarbon radical of a saturated or mono- or polyunsaturated fatty acid. Preferred radicals R ^c are z. N-octyl, ethylhexyl, undecyl, lauryl, tri- decyl, myristyl, pentadecyl, palmityl, margarinyl, stearyl, palmitoleinyl, oleyl and lino IyI.

The amine component is particularly preferably an alkoxylated fatty amine or an alkoxylated fatty amine mixture. Particularly preferred are the ethoxylates. In particular, alkoxylates of amines based on naturally occurring fatty acids are used, such as. As tallow fatty amines containing predominantly saturated and unsaturated Cu, Ci6 and cis-alkylamines or cocoamines containing saturated, mono- and diunsaturated C ₆ -C22, preferably Ci2-Ci ₄ -alkylamines. For alkoxylation suitable amine mixtures are, for. B. various ArmeenR brands of the company Akzo or NoramR brands of the company. Ceca.

Suitable, commercially available alkoxylated amines are, for. B. the Noramox R brands of the company. Ceca, preferably ethoxylated oleyl amines, such as NoramoxR 05 (5 EO units), as well as the products marketed under the brand name LutensoIRFA products from BASF AG.

The copolymerization of the abovementioned esters, monoesters and diesters generally causes pronounced stabilization of the polymer dispersion according to the invention. The polymer dispersions according to the invention reliably retain their colloidal stability of the latex particles when diluted with water or with dilute electrolytes or surfactant solutions.

The esterification for the preparation of the esters, half esters and diesters described above takes place by customary methods known to the person skilled in the art. For the preparation of esters of unsaturated monocarboxylic acids, the free acids or suitable derivatives, such as anhydrides, halides, eg. As chlorides, and (C 1 to C ₄ ) alkyl esters are used. The preparation of half esters of unsaturated dicarboxylic acids is preferably carried out starting from the corresponding dicarboxylic anhydrides. Preferably, the reaction is carried out in the presence of a catalyst, such as. As a dialkyl titanate or an acid such as sulfuric acid, toluenesulfonic acid or methanesulfonic acid. The reaction is generally carried out at reaction temperatures of 60 to 200 C. According to a suitable embodiment, the reaction takes place in the presence of an inert gas, such as nitrogen. Water formed in the reaction can be removed from the reaction mixture by suitable means, such as distillation. If desired, the reaction can be carried out in the presence of customary polymerization inhibitors. The esterification reaction can be carried out substantially completely or only up to a partial conversion. If desired, one of the ester components, preferably the hydroxyl-containing amine, may be used in excess. The proportion of ester formation can be determined by means of infrared spectroscopy.

According to a preferred embodiment, the preparation of the unsaturated esters, half esters or diesters and their further reaction to the invention used polymers A2 without intermediate isolation of the esters and preferably in succession in the same reaction vessel.

For the preparation of the polymers A2, preference is given to using a reaction product of a dicarboxylic anhydride, preferably maleic anhydride, and one of the hydroxyl-containing amines described above.

In addition to the constituents carboxylic acid and esters, half esters and / or diesters, the polymer A2 may contain from 0 to 20% by weight, preferably from 0.1 to 10% by weight, in copolymerized form, other monomers. Useful monomers are the monomers mentioned in connection with the polymer A1, vinylaromatics, such as styrene, olefins, for example ethylene, or (meth) acrylic esters, such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and mixtures thereof are particularly preferred.

The preparation of the polymers A2 is preferably carried out by radical polymerization in bulk or in solution. Suitable solvents for the solvent polymerization are z. As water, water-miscible organic solvents such as alcohols and ketones, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, acetone, methyl ethyl ketone, etc., and mixtures thereof. Suitable polymerization initiators are, for example, peroxides, hydroperoxides, peroxodisulfates, percarbonates, peroxoesters, hydrogen peroxide and azo compounds, as described in more detail below for the preparation of the polymer dispersions of the invention. If desired, the polymers A2 can be prepared separately and isolated and / or purified by the usual method. The polymers A2 are preferably prepared immediately before the preparation of the polymer dispersions according to the invention and used without intermediate isolation for the dispersion polymerization and / or admixed subsequently.

The preparation of the polymers A2 can advantageously also be carried out by polymer-analogous reaction. For this purpose, a polymer which contains 80 to 100 wt .-% of at least one ethylenically unsaturated mono- and / or dicarboxylic acid and 0 to 20 wt .-% of the aforementioned other polymers incorporated, be reacted with at least one hydroxyl-containing amine.

Suitable ethylenically unsaturated mono- and dicarboxylic acids are those mentioned above as the component of the polymers A1 and A2. Suitable amines which have at least one hydroxyl group are likewise those mentioned above. If desired, the acids can be present in the polymer used for polymer-analogous reaction, partly or completely, in the form of a derivative, preferably a C 1 -C 6 -alkyl ester. The preparation of the polymers A2 by polymer-analogous reaction is preferably carried out in a suitable non-aqueous solvent or in bulk. In the reaction in substance, the amine component may optionally be used in excess to serve as a solvent. Preference is given to solvents which form an azeotrope with water and thus allow easy removal of the water formed during the reaction. Preferably, the reaction is carried out in the presence of an esterification catalyst, as described above. The reaction temperature is preferably in a range of 100 to 200 ^° C. Water formed in the reaction can be removed by suitable measures, such as. B. distilling off.

The weight ratio of polymer A1 to polymer A2, on a solids basis, is preferably in the range from 7: 1 to 1: 7, in particular 3: 1 to 1: 3.

In addition to the polymers A1 and A2, the latices according to the invention may contain from 0 to 50% by weight, preferably from 0.1 to 40% by weight, based on the polymer A2, of at least one polyfunctional crosslinker. The crosslinker may contain surface-active, alkoxylated, preferably ethoxylated or propoxylated, alkylamines. Preferred alkylamines are the alkylamines of the formula R ^c NR ^a R ^b , as defined above, which are also contained in the polymer A2, wherein alkylamines of the formula

_/ (EO / PO) _m RN

^X (EO / PO) _n

in which R represents an alkyl, alkenyl or alkylvinyl radical having at least 6 carbon atoms and m and n independently of one another are> 1, are particularly preferred. Preferred radicals R have 8 to 22 carbon atoms.

The alkoxylated alkylamines contained in the polymer A2 and the additional alkylamine crosslinkers may be the same or different compounds.

If desired, the polymer dispersion according to the invention may also contain further crosslinkers, for example an amine or amide crosslinker having at least two hydroxyl groups. Suitable crosslinkers are, in particular, the alkanolamines disclosed in DE 197 29 161, which are hereby incorporated by reference into the disclosure content of the present invention.

Further preferred crosslinkers are β-hydroxyalkylamines of the formula

R ²

1 '3

RNR ³ wherein R ^{1 is} an H atom, a C ¹ to C 10 alkyl group, a C ¹ to C 10 hydroxyalkyl group or a radical of the formula IV

- (CH ₂ CH ₂ O) X (CH ₂ CH (CH ₃ ) O) _V -H (IV)

where in the formula IV the sequence of the alkylene oxide units is arbitrary and x and y independently of one another are an integer from 0 to 10O, where the sum of x and y is> 1 and R ² and R ^{3 are} independently of one another for a d - stand to Cio-hydroxy alkyl group.

Particularly preferably, R ² and R ³ are each independently a C ₂ - to Cs hydroxyalkyl group, and R ¹ is a hydrogen atom, a C to C ₅ alkyl group or a C ₂ - to C ₅ hydroxyalkyl group.

Particular preference is given to diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, methyldiethanolamine, butyldiethanolamine and methyldiisopropanolamine, in particular triethanolamine.

Further preferred β-hydroxyalkylamines are the amines disclosed in DE 196 21 573 as component A, which are hereby incorporated by reference into the disclosure content of the present invention. These preferably include linear or branched aliphatic compounds which have at least two functional amino groups of the type (a) or (b) per molecule

^R ^ N- ^RR ^ N ^{/ R1}

(a) (b)

wherein R is hydroxyalkyl and R 'is alkyl, preferably a compound of formula I.

wherein

A is C ₂ -C ₈ -alkylene, which is optionally substituted by one or more groups independently selected from alkyl, hydroxyalkyl, cycloalkyl, OH and NR ⁶ R ⁷ , wherein R ⁶ and R ^{7 are} independently of each other is H, hydroxyalkyl or alkyl, which is optionally interrupted by one or more oxygen atoms and / or NR ⁵ groups, where R ^{5 is} H, hydroxyalkyl, (CH ₂ ) _n NR ⁶ R ⁷ , where n is 2 to 5 and R ⁶ and R ^{7 have} the meanings given above, or alkyl, which in turn may be interrupted by one or more NR ⁵ groups, wherein R ^{5 has} the meanings given above, and / or may be substituted by one or more NR ⁶ R ⁷ groups, wherein R ⁶ and R ⁷ are those indicated above Possess meanings, stands;

or A is a radical of the formula:

wherein

o, q and s are independently 0 or an integer from 1 to 6, p and r are independently 1 or 2 and t is 0,1 or 2,

wherein the cycloaliphatic radicals may also be substituted by 1, 2 or 3 alkyl radicals and

R ¹ , R ² and R ³ and R ⁴ independently of one another are H, hydroxyalkyl, alkyl or cycloalkyl.

Preferred higher-functionality .beta.-hydroxyalkylamines are in particular at least doubly ethoxylated amines having a molar weight of less than 1 000 g / mol, such as. Diethanolamine, triethanolamine and ethoxylated diethylenetriamine, preferably stoichiometrically ethoxylated diethylenetriamine, d. H. Diethylenetriamine, in which all NH hydrogen atoms are simply ethoxylated on average.

Highly suitable additional crosslinkers are also β-hydroxyalkylamides, preferably the β-hydroxyalkylamides of the formula ## STR1 ## mentioned in US Pat. No. 5,143,582

Particular preference is given to the β-hydroxyalkylamides of the above formula in which R ^{1 is} hydrogen, a short-chain alkyl group or HO (R ³ ) ² C (R ² ) ² C-, n and n 'are each 1, -A- is a - (CH 2) m Group, m is 0 to 8, preferably 2 to 8, R ^{2 are} each hydrogen, and one of the R ³ groups are each hydrogen and the other hydrogen or Ci-Cs-alkyl. Particularly preferred is bis [N, N-di (2-hydroxyethyl)] adipamide.

The addition of the crosslinker generally causes a better curing of the compositions of the invention at a given curing temperature or a cure at low temperature for a given curing time. The weight fraction of the crosslinking agent relative to the sum of polymer A1 and A2 is 0 to 30% by weight, preferably 0.1 to 15% by weight.

Furthermore, a reaction accelerator can be added to the polymer dispersions according to the invention. Preference is given here to phosphorus-containing compounds, in particular hypophosphorous acid and its alkali metal and alkaline earth metal salts or alkali metal tetrafluoroborates. Also, salts of Mn (II), Ca (II), Zn (II), Al (III), Sb (III) or Ti (IV) or strong acids such as para-toluenesulfonic acid, trichloroacetic acid and chlorosulfonic acid can be added as a reaction accelerator , The proportion by weight of the reaction accelerator relative to the sum of polymer A1 and A2 is from 0.1 to 5% by weight, preferably from 0.1 to 2% by weight.

Particularly preferred compositions of the polymer dispersions of the invention are

From 30 to 50% by weight of polymer A1,

70 to 50 wt .-% of polymer A2 and optionally, 0 to 10 wt .-% surface-active alkoxylated alkylamine, 0 to 20 wt .-% hydroxyl-containing crosslinker, 0 to 5 wt .-% reaction accelerator.

The invention further provides a process for preparing an aqueous polymer dispersion as described above, in which at least one ethylenically unsaturated monomer is converted by free-radical emulsion polymerization to give a polymer A1 and the polymerization is carried out in the presence of at least one polymer A2.

The preparation of the polymer dispersion according to the invention is preferably carried out by aqueous emulsion polymerization, wherein a batch, a semi-continuous or a continuous procedure is possible. It proved to be advantageous to meter the polymerizate A2 together with the monomers of the polymer A1 in the form of an emulsion feed into the reaction vessel. If desired, the monomers forming the polymer A1 and the polymer A2 may be partially or completely be fed via two or more separate feeds to the reaction vessel. The monomers can be supplied to the reaction vessel in both pre-emulsified and non-pre-emulsified form. According to a preferred embodiment, at least part of the polymer A2 is fed together with at least one monomer component of A1 to the reaction vessel. Advantageously, aqueous polymer dispersions according to the invention are generally obtained which have a lower viscosity than conventional dispersions. The polymer A2 can be used partially or completely as a reactor master. The use of a defined amount of a seed latex as reactor feedstock is advantageous for the polymer dispersions of the invention for the targeted adjustment of a particle size distribution. In this case, 0 to 25 wt .-%, preferably 0.1 to 10 wt .-%, based on the polymer A1, find a suitable seed latex use.

The preparation of the polymer dispersion is generally carried out in water as a dispersing medium. However, water-miscible organic solvents, such as alcohols and ketones, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, acetone or methyl ethyl ketone, may also be present up to a proportion of about 30% by volume.

The polymer A1 can therefore be prepared by aqueous emulsion polymerization in the presence of the polymer A2 and, if present, preferably in the presence of a surface-active amine as described above.

The polymerization is preferably carried out in the presence of free-radical-forming compounds (initiators). From these compounds it is necessary to use preferably from 0.05 to 10, particularly preferably from 0.2 to 5,% by weight, based on the monomers used in the polymerization.

Suitable polymerization initiators are, for example, peroxides, hydroperoxides, peroxodisulfates, percarbonates, peroxoesters, hydrogen peroxide and azo compounds. Examples of initiators which may be water-soluble or water-insoluble are hydrogen peroxide, dibenzoyl peroxide, dicyclohexyl peroxydicarbonate, dilauroyl peroxide, methyl ethyl ketone peroxide, di-tert-butyl peroxide, acetylacetone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butylperneodecanoate, tert-amyl perpivalate tert-butyl perpivalate, tert-butyl perohexanoate, tert-butyl per-2-ethyl hexanoate, tert-butyl perbenzoate, lithium, sodium, potassium and ammonium peroxodisulfate, azodiisobutyronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride, 2- (carbamoylazo) isobutyronitrile and 4,4-azobis (4-cyanovaleric acid). The known redox initiator systems such. For example, H2O2 / ascorbic acid or t-butyl hydroperoxide / sodium hydroxymethanesulfinate, can be used as polymerization initiators. The initiators can be used alone or mixed with each other, for. B. mixtures of hydrogen peroxide and sodium peroxydisulfate. Water-soluble initiators are preferably used for the polymerization in aqueous medium.

In order to prepare polymers of low average molecular weight, it is often convenient to carry out the copolymerization in the presence of regulators. Conventional regulators can be used for this purpose, for example compounds containing organic SH groups, such as 2-mercaptoethanol, 2-mercaptopropanol, mercaptoacetic acid, tert-butylmercaptan, n-octylmercaptan, n-dodecylmercaptan and tert-dodecylmercaptan, hydroxylammonium salts, such as hydroxylammonium sulfate, Formic acid, sodium bisulfite or isopropanol. The polymerization regulators are generally used in amounts of from 0.05 to 5% by weight, based on the monomers.

To produce relatively high molecular weight copolymers, it is often expedient to work in the polymerization in the presence of crosslinking agents. Such crosslinkers are compounds having two or more ethylenically unsaturated groups, such as diacrylates or dimethacrylates of at least dihydric saturated alcohols, such as. B. ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1, 2-propylene glycol diacrylate, 1, 2-propylene glycol dimethacrylate, butanediol-1, 4-diacrylate, butanediol-1, 4-dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate,

Neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 3-methylpentanediol diacrylate and 3-methylpentanediol dimethacrylate. The acrylic acid and methacrylic acid esters of alcohols having more than 2 OH groups can also be used as crosslinking agents, eg. B. trimethylolpropane triacrylate or trimethylolpropane trimethacrylate. Another class of crosslinkers are diacrylates or dimethacrylates of polyethylene glycols or polypropylene glycols having molecular weights of from 200 to 9,000, respectively.

In addition to the homopolymers of ethylene oxide or propylene oxide, it is also possible to use block copolymers of ethylene oxide and propylene oxide or copolymers of ethylene oxide and propylene oxide, which contain the ethylene oxide and propylene oxide units in random distribution. The oligomers of ethylene oxide or propylene oxide are suitable for the preparation of crosslinking agents, for. For example, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate and / or tetraethylene glycol dimethacrylate.

Also suitable as crosslinking agents are vinyl acrylate, vinyl methacrylate, vinyl itaconate, divinyl diazinyl ether, butanediol divinyl ether, trimethylolpropane trivinyl ether, allyl acrylate, allyl methacrylate, pentaerythritol triallyl ether, triallyl sucrose, pentaallyl sucrose, pentaallylsucrose, methylenebis (meth) acrylamide, divinylethyleneurea, divinylpropylurea, divinylbenzene , Divinyldioxane, triallyl cyanurate, tetraallylsilane, tetravinylsilane and bis- or polyacrylsiloxanes (eg Tegomere® from Th. Goldschmidt AG). The Crosslinkers can be used in amounts of 0 to 5, preferably in amounts of 10 ppm to 5 wt .-%, based on the monomers to be polymerized.

In addition to the constituents mentioned, the compositions according to the invention may contain customary additives depending on the intended use.

The components optionally additionally present in the composition according to the invention are added after the end of the emulsion polymerization.

Further, the compositions of the invention may contain conventional additives depending on the application. For example, they may contain bactericides or fungicides. In addition, they may contain water repellents to increase the water resistance of the treated substrates. Suitable water repellents are customary aqueous paraffin dispersions or silicones. Further, the compositions may contain wetting agents, thickeners, plasticizers, retention aids, pigments and fillers.

Finally, the compositions of the invention conventional fire-protective agents, such as. For example, aluminum silicates, aluminum hydroxides, borates and / or phosphates.

Frequently, the compositions also contain coupling reagents, such as alkoxysilanes, for example 3-aminopropyltriethoxysilane, soluble or emulsifiable oils as lubricants and dust binders, and wetting assistants.

The compositions of the invention can also be used in admixture with other binders, such as urea-formaldehyde resins, melamine-formaldehyde resins or phenol-formaldehyde resins, and with epoxy resins.

The compositions according to the invention are formaldehyde-free. Formaldehyde-free means that the compositions according to the invention do not contain any substantial amounts of formaldehyde and that no substantial amounts of formaldehyde are liberated even during drying and / or curing. In general, the compositions contain <100 ppm formaldehyde. They allow the production of moldings with a short curing time and give the moldings excellent mechanical properties.

The thermally curable, formaldehyde-free compositions according to the invention are essentially unvetected before use and therefore thermoplastic. If necessary, however, a low degree of pre-crosslinking of the polymer A1 can be achieved. be put, z. By use of monomers having two or more polymerisable groups.

The dispersions of the invention consisting essentially of finely divided emulsion of A1 and an aqueous phase containing the polymer A2 and optionally separately added or unreacted in the esterification amine, and optionally other water-soluble additives, eg. B. crosslinker.

This can lead to the formation of superstructures in the aqueous phase, such as. As formed by lamellar or spherical aggregates lyotropic phases.

The monomer composition is generally chosen such that for the polymer A1, a glass transition temperature Tg in the range of -60 C to +150 C results. The glass transition temperature Tg of the polymers can be prepared in a known manner, for. B. by differential scanning calorimetry (DSC) can be determined. The Tg can also be approximated using the Fox equation. After Fox TG, Bull. Am. Physics Soc. 1, 3, page 123 (1956) applies: 1 / Tg = xi / Tgi + x ₂ / Tg ₂ + ... + x _n / Tg _n where X _n is the mass fraction (wt .-% / 100) of the Monomer n is, and Tg _{n is} the glass transition temperature in Kelvin of the homopolymer of the monomer n. Tg values for homopolymers are listed in Polymer Handbook 3rd Edition, J. Wiley & Sons, New York (1989). For further processing into fiber insulation boards, preference is given to using polymers A1 having a glass transition temperature in the range from 60 to 120 ^° C. For further processing to cork the glass transition temperature is preferably in a range from -50 to 90 ⁰ C.

The polymer dispersions of the invention are finely divided, stable latices. The weight-average particle size of the latex particles is about 10 to 1500 nm, preferably 20 to 1000 nm, particularly preferably 30 to 500 nm, measured with the aid of the analytical ultracentrifuge (AUC).

The polymer dispersions according to the invention can be diluted indefinitely with water or dilute salt or surfactant solutions without coagulating the latex particles. The compositions of the invention have a content of nonvolatile matter (solids content) in the range of about 20 to 75 wt .-%, preferably 25 to 65 wt .-%. The viscosity (at a solids content of 40 wt .-%) is generally in a range of about 10 to 4000 mPas, measured with a rotational viscometer in accordance with DIN 53019 at 23 C and a shear rate of 250 s. ¹

Furthermore, the compositions of the invention may contain conventional auxiliaries in the coating and impregnation technology. Examples of this are fine Partially inert fillers, such as aluminum silicates, quartz, precipitated or pyrogenic silica, light and heavy spar, talc, dolomite or calcium carbonate; coloring pigments, such as titanium white, zinc white, iron oxide black, etc., foam inhibitors, such as modified dimethylpolysiloxanes, and adhesion promoters and preservatives.

The components of the composition according to the invention are generally contained in the coating composition in an amount of from 1 to 65% by weight. The proportion of inert fillers is generally from 0 to 85 wt .-%, the water content is at least 10 wt .-%.

The binders of the invention are useful as binders for substrates such as e.g. for the production of fiber webs.

The non-woven fabrics may consist of natural and / or synthetic fibers. Examples of natural fibers are cellulose fibers of various origins, such as pulp and staple fiber, as well as fibers of cotton, hemp, jute, sisal and wood, wool, and mixtures of at least two of the fiber types mentioned. Preferably used fibers from the group are fibers of jute, sisal and wood. Examples of synthetic fibers are viscose, polyester, polyamide, polypropylene, polyethylene, polyacrylonitrile and polyvinyl chloride fibers and carbon fibers, glass fibers, ceramic fibers and mineral fibers, and mixtures of at least two of the mentioned types of fibers. Polyester fibers and mixtures of polyester fibers and glass fibers are preferably used for producing the bonded nonwoven fabrics. Polyester fibers can be recovered from recycled material by melt spinning and used to make a carrier web. The nonwovens may e.g. consist of staple fibers or spun fibers and mixtures of these types of fibers.

As is known, they are produced mechanically by needling or hydroentanglement of a wet-laid or air-laid nonwoven fabric and / or by chemical solidification with polymeric binders. For the production of bonded fiber webs, for example, at least one binder in an amount of 0.5 to 30, preferably 15 to 20 wt .-%, based on the solids content of the binder and sheet-like fiber structure such as nonwovens used. The binder serves to solidify the nonwovens. It can be applied, for example, by spraying, dipping, impregnating or peeling or by treating the fiber structure with a foam.

The nonwovens for example have a basis weight of 10 to 700 g / m ² , preferably from 50 to 500 g / m ² . In most cases, the basis weight of the non-reinforced nonwovens is 75 to 300 g / m ² . The impregnated with a binder webs are for solidification to temperatures in the range from 130 ⁰ C to 230 ⁰ C, preferably heated 150 to 210 ⁰ C. The duration of the heating depends essentially on the temperature, the water content and the particular fiber that makes up the nonwoven fabric. In most cases, the nonwoven webs impregnated or coated with at least one binder are heated for 0.5 to 5, preferably 1.5 to 3 minutes. During heating, water vapor first softens, simultaneously or subsequently the thermally curable binder is crosslinked.

In the case of use as binders for nonwoven fabrics, the binders according to the invention may also contain additives such as silicates, silicones, boron-containing compounds, lubricants or wetting agents.

The invention also relates to the use of bonded nonwoven fabrics, which are solidified with the polymeric binder, as a carrier material for bituminous roofing membranes, as well as roofing membranes comprising the polymeric binder.

The roofing membranes are obtained by coating or impregnating the solidified nonwovens described above with bitumen on both sides or on one side. For example, a web made of a suitable nonwoven is passed through a bituminous melt and the web impregnated in this way is pressed off. This process can be repeated one or more times. The bitumen application, based on the consolidated nonwoven, based on the basis weight, for example, 25: 1 to 2: 1, preferably 15: 1 to 5: 1 wt .-%.

The roof membranes according to the invention surprisingly have a higher heat resistance compared to the known roofing membranes, lower water absorption at comparable tear strength.

Another use according to the invention of the binders is the use for the production of filter materials, in particular filter papers or filter fabrics. Tissue materials may, for example, be Ce I Iu loose, cotton, polyester, polyamide, PE, PP, glass fleece, glass wool. It may be advisable to adjust the aqueous polymer solutions to a pH of from 2 to 8, in particular from 3.0 to 6.5, before application to the corresponding paper or tissue by addition of various inorganic or organic bases. Suitable bases include triethanolamine, diethanolamine, monoethanolamine, hydroxyalkylamines, ammonia, organic mono- or polyfunctional amines, alcoholates and Metallalkylverbin- compounds, but also inorganic bases such as sodium hydroxide or potassium hydroxide. By adjusting the pH to the specified value range, inter alia, the falling of the bursting strength after storage or thermal stress is reduced and thus a high heat resistance is achieved. The application of the polymer solution to be used according to the invention to the filter materials, that is, inter alia, to filter paper or filter fabric, is preferably carried out by the so-called impregnation method or by spraying. The aqueous polymer solutions are applied by gluing onto the filter materials. It is advisable, after gluing the filter materials with the aqueous polymer solutions for another 0.1 to 60 minutes, especially for 1 to 60 minutes at temperatures of 100 to 250 ⁰ C, in particular from 110 to 220 ⁰ C to anneal, ie cure.

The inventive use of the aqueous polymer solution as a binder for filter materials has the consequence that the treated filter materials u.a. have an increased mechanical stability (higher tensile strength and bursting strength), especially after storage in a humid climate and at elevated temperature. Furthermore, the inventive use of the aqueous binder causes the resulting filter materials u.a. are characterized by high chemical resistance, for example to solvents, without affecting the permeability (pore size) of the filter material. By using the aqueous polymer solutions, it is also observed that these impart high strength to the filter materials already after drying (dry tensile strength), but the filter materials are still good at deformation below the curing temperature of the aqueous polymer solutions even after deformation by folding, creasing or Undergo pleating. After the subsequent thermal curing (tempering), the polymer solutions give the resulting filter materials according to the invention, essentially filter papers or filter cloths, a high dimensional stability. This property enables the production of semi-finished products and thus the separation of the manufacturing process into individual decoupled production steps.

Further uses according to the invention are the use of the aqueous polymer solutions as binders for cork, nonwovens, mats or slabs, as taped carrier webs, as nonwovens for cleaning and wiping cloths or as inliners or carrier material for floor coverings, such as, for example, made of PVC.

Production of nonwovens

Polyester spunbonded nonwovens having a basis weight of about 150 g / m ² are impregnated with the binder in a HVF impregnating machine with foulard from Mathis (rubber roller Shore A = 85 ° / steel roller). The raw fleece of 40 cm length and 37 cm width is guided in the longitudinal direction through the impregnating bath, and squeezed between two vertically mounted rollers (rubber / steel). The impregnating liquor has a solids content of 15% by weight. The wet application in the case of a 15% by weight liquor is about 130-135%. The drying of the fleece is then carried out in a laboratory dryer LTV with needle frame made by Mathies. The impregnated fleece is placed on a hinged needle frame, fixed, and 3 min. dried at 200 ⁰ C in the oven and cured.

The resulting fixed application is 20% by weight (+/- 0.5% by weight)

Order in% = mass binder (solid) / mass fibers

Tests of nonwovens

To characterize the water absorption of the nonwoven nonwoven strips are dipped for a period of 10 min 25 mm in a test liquid (0.1 wt .-% methylene blue in water) and then stripped between 2 filter papers. After drying at room temperature, the height of rise of the test liquid is determined.

The determination of the tensile strength and elongation at break at room temperature according to DIN 52123 using a tearing machine from Frank (Model 81565). The HZK value is obtained by dividing the resulting tear force by the basis weight of the nonwoven.

The characterization of the thermal stability of PET woven material takes place by tensile stretching experiments by means of a tearing machine from Zwick with integrated temperature chamber (T = 200 ⁰ C). For each measurement, 5 specimens each 50 * 210 mm (longitudinal direction) are prepared. The clamping length is 100 mm, the withdrawal speed 150 mm / min. At T = 200 ⁰ C, the nonwoven elongation is determined with increasing tensile force. The strain averaged over the 5 specimens is given for defined tensile forces.

Example A

X1 g of water, Y1 g of a 43% acrylate resin solution A ¹ and 5% of feed 2 are introduced into a 2.51 glass vessel with anchor stirrer and heated to 85 ° C. Then 10% of feed 1 is added. After 2 minutes at this temperature, the remainder of feed 1 in 3.5 h and the remainder of feed 2 in 3 hours to metered. The mixture is then postpolymerized for a further 1 h at this temperature and the reaction mixture is cooled. The dispersion thus prepared has a solids content of 25% and a pH of 2.5. Subsequently, 18% triethanolamine based on acrylate resin solution (solid) is added.

¹ Comparative Example from DE 10224922 Template:

Ex. 1 Bspl. 2 Bspl. 3 Bspl. 4 Bspl. 5

Ex. 6 Bspl. 7 Bspl. 8 Bspl. 9

Assembly of feed 1 in g:

Sodium persulfate 7% 57.1

Composition of feed 2 in g:

Example B

In a 2.51 glass vessel with anchor stirrer, X2 g of water, Y2 g (= 50%) of a 50% acrylate resin solution B ² and 5% of feed 2 are initially charged and heated to 85.degree. Then 10% of feed 1 is added. After 2 minutes at this temperature, the remainder of feed 1 in 3.5 h and the remainder of feed 2 are added in 3 h. The mixture is then polymerized for a further 1 h at this temperature and the reaction mixture is cooled. The dispersion thus prepared has a solids content of 25% and a pH of 2.5.

Template:

Ex. 10 Bspl. 11 Bspl. 12 Bspl. 13 Bspl. 14

Assembly of feed 1 in g

Sodium persulfate 7% 57.1

Composition of feed 2 in g:

Bspl.10 Bspl.11 Bspl.12 Bspl.13 Bspl.14

Examples C

230 g of water, 17.6 g of a 33% by weight polystyrene seed having a particle diameter of 28 nm and 10% by weight of the feed 2 are introduced into a 2.5 l glass vessel with anchor stirrer and heated to 85 ° C. Subsequently, 18 g of a 7% strength by weight aqueous sodium persulfate solution are added. After 2 min. Feed 1 and the remainder of feed 2 are metered in over the course of 3 hours at this temperature. subse-

Corresponds to binder G from DE 19606394 ßend is postpolymerized at this temperature for 1 h and cooled, the reaction mixture. The dispersion thus prepared has a solids content of 52% by weight and a pH of 3.7.

Composition of feed 1 in g:

7% strength by weight aqueous sodium persulfate solution 78.6

Composition of feed 2 in g:

Disp. 1 disp. 2 Disp. 3 disp. 4 Disp. 5

The dispersions are soaped with additional emulsifier. Mixtures of the dispersions with acrylate resin solution A ³ , B ⁴ , C ⁵ are carried out in a 1.0 l glass vessel with magnetic stirrer by initially charging the acrylate resin solution and adding the dispersion within 1 min.

³ Corresponds to binder C from DE19606394

⁴ Corresponds to binder G from DE 19606394

⁵ Comparative Example from DE10224922

⁶ % dispersion = 100% - proportion of acrylate resin solution

⁷ 32% by weight; Use amount 2.5% by weight based on the dispersion

Comparative Examples (N-methylol-containing binders)

⁸ 10% by weight, based on the polymer fraction of the binder, of ⁹ 20% by weight, based on the polymer fraction of the binder, of ¹⁰ 10% by weight, based on the polymer fraction of the binder

¹¹ 10% by weight, based on the polymer content of the binder

¹² without TEtA

¹³ % by weight, based on the polymer content of the binder

¹⁴ 8% by weight, based on the polymer content of the binder

¹⁵ % by weight, based on the polymer content of the binder, of ^{16 to} 10% by weight, based on the polymer content of the binder

¹⁷ 20% by weight, based on the polymer content of the binder

¹⁸ 20% by weight, based on the polymer fraction of the binder, ¹⁹ 10% by weight, based on the polymer fraction of the binder Application technical results

Claims

claims

Use of a thermally curable aqueous composition containing dispersed polymer particles at least

a) containing a polymer A1,

98-100 wt .-% of ethylenically unsaturated monomers A, wherein up to 20 wt .-% of the monomers A may contain glycidyl and / or hydroxyl groups and / or A- min- / amide and the polymer <5 wt .-% of a α, ß-ethylenically unsaturated mono- or dicarboxylic acid and at least 1

% By weight of acrylonitrile in copolymerized form, and 0-5 wt .-% of a bi or multi-functional monomer and b) a serum-soluble polymer A2, which in polymerized form 60-100 wt .-% of at least one α, ß-ethylenic unsaturated mono- or dicarboxylic acid whose carboxylic acid groups can form an anhydride group, salts or mixtures thereof contains c) and a polyfunctional crosslinker or mixtures thereof d) and optionally di- or trivalent metal ions added in the form of hydroxides, oxides, carbonates or bicarbonates become

as a binder for substrates.

2. Use according to claim 1, characterized in that the aqueous composition is prepared by free-radical emulsion polymerization of the polymer A1 in the presence of polymer A2.

3. Use according to claim 1, characterized in that the aqueous composition is obtained by mixing the polymers A1 and A2.

4. Use according to any one of claims 1 to 3, characterized in that are used as ethylenically unsaturated mono- or dicarboxylic acids, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, their anhydrides or mixtures thereof.

5. Use according to one of claims 1 to 4, as a binder for fibers, mats and nonwovens.

6. Use according to one of claims 1 to 4, as a binder for glass fibers, nonwovens, mats, mineral fibers, nonwovens and mats.

7. Use according to one of claims 1 to 6, as a carrier material for bitumen roofing membranes.

8. Use according to one of claims 1 to 6 as a nonwoven fabric for cleaning and wiping cloths.

9. Use according to one of claims 1 to 6 as a binder for filter materials.

10. Use according to one of claims 1 to 6 as a binder for wallpaper carrier webs.

11. Use according to one of claims 1 to 6 as a binder for inliner or carrier material for floor coverings.

12. A process for producing bonded fiber webs, characterized in that nonwoven fabrics coated with an aqueous binder according to any one of claims 1 to 4, sprayed or impregnated and then dried.

13. The method according to claim 12 for the production of bonded glass fiber webs or mats.

14. Bound fiber webs or mats, obtainable by using a formaldehyde-free, aqueous binder according to one of claims 1 to 4.

15. Bound glass fiber nonwovens or mats, obtainable by using a formaldehyde-free, aqueous binder according to one of claims 1 to 4.

16. roof sheets containing bonded non-woven fabrics or mats according to claim 14.

17. roof sheets containing bound glass fiber webs or mats according to claim 15.