DE1669731A1 - Process for crosslinking copolymers of ethylenically unsaturated compounds containing optionally etherified N-methylolamide groups - Google Patents

Description

Badische Anilin- & Soda-i'abrik AG

Our symbols: O.Z. 25 195 Wd / Ho Ludwigshafen / Rhine, October 24th, 1967

Process for the crosslinking of optionally etherified N-methylolamide groups containing copolymers of ethylenically unsaturated compounds

Copolymers of ethylenically unsaturated compounds which contain N-methylolamide groups or etherified N-methylolamide groups are widely used in the form of their aqueous dispersions or in the form of their solutions in water or organic solvents. As ethylenically unsaturated monomers, they usually contain esters of acrylic or methacrylic acid or butadiene, optionally polymerized as a mixture with styrene and / or acrylonitrile. The copolymers are used, for example, as binders for nonwovens, as adhesives, for coatings, such as on metals, and for textile and leather finishing. When heated to temperatures of about 90 to 150 ^° C., in particular in the presence of acidic catalysts, the copolymers crosslink and products are obtained whose tensile strength is increased and their solubility in organic compounds. Solvents and water is reduced.

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Acidic catalysts are, for example (DAS 1 191 784 and French patent specification 1 388 4-73 ') organic or inorganic acids such as boric acid, phosphoric acid, acetic acid and p-toluenesulfonic acid or compounds that split off acids

Ammcn i iimr> i tra ~ - fertilize, such as zinc chloride, magnesium chloride, aluminum chloride, / or ammonium oxalate used. The tensile strength of the using Copolymers crosslinked with such catalysts are, however, still in need of improvement. In addition, the time span is the mixtures from the polymers containing N-methylolamide groups or their solutions or dispersions and such catalysts can be stored at room temperature without noticeable crosslinking, relatively briefly. The catalysts can therefore should only be added shortly before processing.

It is furthermore, for example from the US patent 2,978,437 and the Belgian patent specification 584,000 are known to be ethylenic in copolymers containing N-methylolamide groups of unsaturated compounds, monomers containing carboxyl groups, such as acrylic acid in particular, to be polymerized as further comonomers. In the case of copolymers of this type which, in addition to the N-methylolamide groups, also contain carboxyl groups, the The addition of low-molecular, acidic substances is not absolutely necessary. Aqueous dispersions of such copolymers are storage-stable for a long time, but even in this case, for example, the tensile strength of the cross-linked copolymers does not to be desired. The softness and, above all, the elasticity of such copolymers are often un-

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It has now been found that etherified N-methylolamide groups can be obtained containing copolymers of ethylenically unsaturated compounds with the addition of carboxyl groups containing substances as catalysts and with heating can advantageously crosslink by containing as carboxyl groups Substances 0.2 to 10 percent by weight, based on the optional polymer containing etherified K-methylolamide groups, of polymers of ethylenically unsaturated carboxylic acids which contain at least 15% of their weight in carboxyl groups contain, or the ammonium salts of such polymers used.

The new process is suitable for the crosslinking of all copolymers of ethylenically unsaturated compounds _for the N-methylolamide groups, ie groups of the general formula I.

-CON - CH ₂ - OH,

or etherified N-methylolamide groups, i.e. groups of the general Formula II

-CON - CHp - 0 - C -,

contain. In general, such copolymers contain 0.5 to 20 percent by weight of monomers with N-methylolamide groups

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polymerized in pen or etherified N-methylolamide groups. The proportion of these monomers in the copolymers is usually the same 2 to 10 percent by weight. As monomers with N-methylolamide groups are above all N-methylolacrylamide and methacrylamide, also the N-methylol compounds of maleic acid mono- and diamids, of maleimide and of the amides of fumaric and itaconic acid. Monomers with etherified N-methylolamide groups are e.g. the ethers of the mentioned N-methylolamide monomers, especially their alkyl ethers. Of particular interest are the alkyl ethers, which differ from such N-Me thy 1 ο 1-amide monomers and straight-chain or branched alkanols containing 1 to 4 carbon atoms, such as above all the methyl, ethyl, isopropyl, η-butyl, isobutyl and tert-butyl ethers of N-methylol acrylamide and N-methylol methacrylamide.

The ethylenically unsaturated monomers contained in the optionally etherified copolymers containing N-methylolamide groups include, for example, 1,3-dienes, such as butadiene or isoprene, vinylaromatic compounds, such as styrene, O (-methylstyrene, ethylstyrenes, 4-methylstyrene or 2-chlorostyrene) , Nitriles (λ, ß-ethylenically unsaturated carboxylic acids, such as especially acrylonitrile and methacrylonitrile, esters O ( , ß-ethylenically unsaturated carboxylic acids containing 1 to 20 carbon atoms, straight-chain or branched alkanols, such as especially the acrylic, methacrylic and maleic acid esters of straight-chain or branched , 1 to 10, and especially 1 to 4 carbon atoms

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Alkenols, such as methyl, ethyl, η-butyl, 2-ethylhexyl, n-decyl, tert-butyl, lauryl and stearyl esters, vinyl esters such as vinyl acetate, vinyl propionate, vinyl laurate and Vinyl stearate, furthermore vinyl ethers and vinyl ketones are polymerized in. The copolymers can also advantageously contain small amounts, preferably 0.1 to 4% of their weight, of such monomers in polymerized form which contain 2 polymerizable double bonds. Particularly suitable compounds of this type are the neutral esters of acrylic and / or methacrylic acid with diols, in particular the alkanediols containing 2 to 6 carbon atoms, such as glycol and butanediol (1,4) diacrylate, and allyl esters, such as allyl acrylate and diallyl phthalate, and also divinylbenzene Ethylenically unsaturated monomers containing 0.5 to 5 percent by weight of acidic groups, such as maleic acid, acrylic acid, methacrylic acid and / or vinylsulphonic acid, are incorporated as polymerized units lten. The polymers optionally containing ethereal N-methylolamide groups can be present in the form of their dispersions or as solutions, for example in organic solvents such as methyl ethyl ketone, butyl acetate and / or toluene.

The polymers of ethylenically unsaturated carboxylic acids acting as catalysts should contain at least 15 ° of their weight in carboxyl groups. For example, the homopolymers and copolymers of ethylenically unsaturated mono- and / or dicarboxylic acids, such as, in particular, acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, are suitable. For the copolymers of the

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Ethylenically unsaturated carboxylic acids occur as comonomers especially esters of acrylic and / or methacrylic acid with 1 to 20, preferably 1 to 10 and in particular 1 to 4 carbon atoms containing alkanols, such as methyl, ethyl, propyl, η-butyl, ter-t.-butyl, hexyl, cyclohexyl, 2-ethylhexyl, Lauryl and stearyl esters in question. Suitable comonomers are also vinyl esters, such as vinyl acetate, vinyl propionate, vinyl laurate and vinyl stearate, .vinylaromatic compounds, such as in particular Styrene, 1,3-dienes, such as butadiene in particular, and amides and nitriles e (, ß-unsaturated carboxylic acids, such as acrylonitrile in particular, also acrylamide and methacrylamide.

The polymers of ethylenically unsaturated carboxylic acids can in the form of their aqueous dispersions or in the form of their solutions in water or organic solvents such as butyl acetate, Methyl ethyl ketone, acetone and toluene are used, generally those solvents are chosen which are compatible with the solvents in which the K-methylolamide groups containing polymers are used.

Aqueous dispersions of copolymers of 30 to 60 percent by weight are used as crosslinking catalysts for the new process Acrylic and / or methacrylic acid and 40 to 70 percent by weight, based on the polymer, acrylic and / or methacrylic acid esters ναι 2 to 4 carbon atoms containing alkanols, like above all ethyl acrylate, of particular interest. They can be used with particular advantage as catalysts for crosslinking

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aqueous dispersions of copolymers from 1 to 10 percent by weight the optionally etherified E-methylolamide compounds of fit, ß-ethylenically unsaturated carboxylic acids with 2 to 5 carbon atoms, such as especially K-methylol methacrylamide, and containing predominant amounts of acrylic and / or methacrylic acid esters of 1 Ms 10 carbon atoms Alkanols, especially ethyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate, or butadiene, or mixtures of butadiene with up to 70 percent by weight of the mixture of styrene and / or Acrylonitrile can be used.

The amount of polymer of the ethylenically unsaturated carboxylic acids with at least 15 percent by weight of carboxyl groups can be varied within wide limits. In general, 0.5 to 5 percent by weight of such polymers (solid) are used, based on the amount of the polymer (solid) which may contain etherified H-methylolamide groups. In some cases , quantities smaller than 0.5 % or larger quantities than $ 5 can be advantageous.

In the process, the polymers containing N-methylolamide groups and the polymers of the ethylenically unsaturated carboxylic acids are mixed, generally in the form of their solutions or dispersions. The mixtures obtained can be stored for a relatively long time, especially if they are aqueous dispersions, and can usually be processed for up to 5 months after their preparation. The long shelf life of such mixtures is a particular advantage of the

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Procedure. The mixtures can in a conventional manner, for example as a binder for nonwovens, as adhesives, e.g. for laminating textiles with foams, for manufacturing of coatings and coverings on wood, metal, textiles, paper, etc. are used.

The optionally N-methylol amide groups etherified containing copolymers crosslink in the presence of the polymers of ethylenically unsaturated carboxylic acids at elevated temperature, particularly at temperatures above 80 C, usually at temperatures of 90-170 ⁰ C, preferably between 100 and 150 C, rapidly. The copolymers crosslinked according to the invention are distinguished by a particularly high tensile strength and solvent resistance as well as good wash resistance and in this respect exceed the products which have been crosslinked using the usual crosslinking catalysts such as ammonium oxalate, maleic acid or zinc chloride.

The parts and percentages given in the following examples are based on weight. The K values given therein were according to H. Pikentscher, Cellulose Chemie, Volume (1932) page 58, measured.

example 1

100 parts of a 20% strength aqueous dispersion of a commercial copolymer of 5 # N-methylol methacrylamide and 95 ° / ° n-butyl acrylate is mixed with 2 parts of a 10% strength aqueous

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Solution of a polyacrylic acid with a K value of 30 mixed. The carboxyl group content of the polyacrylic acid is 63% . A commercially available polyamide fiber fleece of 60 g / m made of 3-denier polyamide fibers with a length of 60 mm is impregnated and squeezed off with the mixture in such a way that the finished nonwoven fabric, after drying, is $ 100, based on the amount of polyamide fibers of the N-methylolamide groups containing copolymer. The impregnated and squeezed mat is then dried after-treated for 5 minutes at 120 ⁰ C and 15O ⁰ C in 3.Minuten, wherein the binder crosslinked. A nonwoven fabric is obtained, the tensile strength of which in the dry state is 225 kg / cm, in per-

2 chlorethylene-wet condition (15 minutes storage) HO kg / cm amounts to.

Comparative experiment

The same amount of ammonium oxalate is used instead of the polyacrylic acid or maleic acid, then, under otherwise identical conditions, nonwovens are obtained whose tensile strength is dry

2
Condition 150 or 165 kg / cm, in the perchlorethylene-wet condition only 95 or 105 kg / cm.

Example 2

100 parts of a 20 follow aqueous dispersion of a copolymer prepared in usual manner from 3 ° / ° N-methylolmethacrylamide, 1% acrylic acid, 3 ^a / ° acrylonitrile and 93 "ß> n-butyl 'acrylate with 5 parts of a 20 ^ aqueous Dispersion of a conventionally prepared copolymer from 10 $

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Acrylic acid, 34 $ methacrylic acid and 56 ^σ /> ethyl acetate (carboxyl group content 23%) mixed. The mixture is stable on storage for 5 months at room temperature. A polyamide fiber fleece is impregnated with it as indicated in Example 1 and a nonwoven fabric is obtained,

its tensile strength in the dry state 215 kg / cm, in per-

chlorethylene-wet state is 90 kg / cm.

Example 3

To 100 parts of a 20 figs aqueous dispersion of a copolymer prepared in usual manner from 3 fe N-methylolmethacrylamide, 1 fe acrylic acid, 3 fe acrylonitrile and 93 fe butyl acrylate 2 parts of a 10 figs solution of the ammonium salt is added a polyacrylic acid of the K value 250 ( Carboxyl group content 51 fe) . A polyamide fiber fleece is impregnated with the mixture as described in Example 1. Under otherwise identical conditions, a nonwoven fabric is obtained which has a tensile strength of 195 kg / cm in the dry state and in the perchlorethylene-wet state

the tensile strength is 105 kg / cm.

Comparative experiment

If, instead of the ammonium salt of polyacrylic acid parts of a 10 follow wäiirigen Magnesiumch loridlösung, we obtain a nonwoven fabric whose tensile strength kg / cm in the dry state only 150 kg / cm, wet perchlorethylene-in condition 35 under otherwise identical conditions.

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Example 4

Mixing 100 parts of a 20 $ aqueous dispersion of a copolymer produced in a conventional manner from 4 $ N-methylol methacrylamide, 3 i ° diallyl phthalate, 1 fo acrylamide, 7 # acrylic acid, 13 $> acrylonitrile and 72 $> n-butyl acrylate with 1 part a 20 $ aqueous dispersion of a copolymer prepared in conventional manner from 10 $> acrylic acid, 34 ° / ° of methacrylic acid and 56 ° J> ethyl acrylate (carboxy lgrupp closely ehalt 23 i °). The mixture obtained is extremely stable on storage. A polyamide fiber fleece is impregnated with it according to the information in Example 1 and, under otherwise identical conditions, a fleece material is obtained whose tensile strength in the dry state is 300 kg / cm ^,

2 in the perchlorethylene-wet state is 210 kg / cm.

Comparative experiment

If instead of the aqueous dispersion of the copolymer, which contains 23 fo carboxyl groups, 2 parts of a 20 maleic acid solution in water are used, a polyamide nonwoven fabric is obtained under otherwise identical conditions, the tensile strength of which in the dry state is 265 kg / cm, in perchlorethylene

2
when wet is 165 kg / cm.

Example 5

• is mixed 100 parts of a 20 $ aqueous dispersion of a copolymer produced in a conventional manner from 5 ° / o N-methylolmethacrylamide, 2 fo diallyl phthalate, 32 <fo styrene and

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61 io butadiene with 1 part of a fig aqueous dispersion of the copolymer indicated in Example 2 and having a carboxyl group content of 23 $. As indicated in Example 1, a polyamide fiber fleece is impregnated with the mixture obtained, which is very stable on storage. Under otherwise identical conditions, a polyamide nonwoven is obtained, the tensile strength of which in the dry state is 220 kg / cm, in perchlorethylene

when wet is 100 kg / cm.

Comparative experiment

Is used instead of the 23 $ containing carboxyl groups Copolymer the same amount of ammonium oxalate as a catalyst, one obtains one under otherwise identical conditions Polyamide nonwoven fabric, its tensile strength when dry

is only 95 kg / cm.

Example 6

100 parts of a 20 $ aqueous solution of the copolymer containing N-methylolamide groups specified in Example 2 are mixed with 2 parts of a 30% solution of a copolymer of 50 parts each of vinyl isobutyl ether and maleic anhydride in toluene, which is subsequently crosslinked with 2 i » hexamethylenediamine and with 25 #, aqueous ammonia was neutralized, added. The saponification product has a carboxyl group content of 42 jt. A polyamide fiber fleece is impregnated with the mixture as described in Example 1 under otherwise identical conditions. A polyamide nonwoven is obtained,

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dessert tensile strength when dry 220 kg / cm, in

perchlorethylene wet state is 135 kg / cm.

Example 7

To 100 parts of a 50 $ aqueous dispersion of a copolymer of 3 ⁰ A N-methylolmethacrylamide, ^σ _22/0 acrylonitrile, 3 i ° ethylene glycol monoacrylate, 8 $ methyl acrylate and
52 ° β> n-butyl acrylate are added 2 parts of a 25 ^ strength aqueous dispersion of the copolymer used in Example 2 with a carboxyl group content of 23% . The pH of the mixture is adjusted by addition of ^S 25% aqueous ammonia to 6 to eighth With the adhesive mixture obtained, a commercial cotton poplin is coated in the usual manner at an application rate of 28 to 32 g / m 2 and a polyamide fabric is applied to the coated cotton poplin under slight pressure. It is dried at room temperature and tempered at 95 ° C. for 3 minutes. The adhesive strength of the fabric laminated on top of one another is then measured on 2 cm wide strips in a commercially available tearing machine at a feed rate of
150 mm / min, determined. When dry it is 1,300 g / 2 cm, after 1/2 hour storage in perchlorethylene or perchlorethylene.
Water in perchlorethylene-wet state 270 g / 2 cm and in
water-wet state 240 g / 2 cm.

Attempted comparison

One uses an adhesive mixture that instead of the carboxyl groups contained copolymer of the carboxyl group

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Content 23 ? 2.5 parts of 20% aqueous maleic acid solution and changes the pH of the adhesive, which is 5 after the addition of maleic acid, not by adding ammonia, but sets 2 parts of a 30 % aqueous solution of a commercially available one Adding a thickener based on polyvinylpyrrolidone, under otherwise the same conditions, one obtains a lamination of the Polyaniiageweb.es on the cotton poplin, whose shear strength in the dry state only 900 g / 2 cm, in the perchlorethylene-wet state only 160 g / 2 cm , and in the water-wet state is only 230 g / 2 cm.

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Claims (1)

Claim Method for crosslinking possibly etherified N-Methylo! Amide group-containing copolymers of ethylenically unsaturated compounds with the addition of carboxyl group-containing substances as catalysts with heating, characterized in that the carboxyl group-containing substances are 0.2 to 10 percent by weight, based on the optionally etherified polymers containing N-methylolamide groups, of polymers of ethylenically unsaturated carboxylic acids which contain at least 15 ^ o their weight of carboxyl groups, or their ammonium salts are used. Badische Anilin- & Soda-Fabrik AG /IN THE 109830/1867