DE2405934A1 - Compsn. for reversal coating of textiles - comprising polyurethane, vinyl copolymer and diene graft copolymer, giving better light resistance - Google Patents

Abstract

In coating textile flat goods by the reversal process, (a) a soln. of a mixt. contg. (A) 50-90 (70-80) wt. % of a linear polyurethane, with no reactive end-gps., from a dihydroxy cpd. of MW 500-4000, an aromatic diisocyanate and a diol of MW 62-450, (B) 0-50 (5-25) wt. % of a vinyl copolymer and (C) 1-50 (5-25) wT. % of a diene graft copolymer, is applied to a release carrier and is dried; (b) a bonding layer soln. is applied; (c) the surface is covered with the textile; (d) the solvent of the bonding layer is evapd.; and (e) the coated textile is removed from the carrier. The coatings have better light resistance.

Description

Textile coating with mixtures of polyurethanes, vinyl copolymers and diene graft polymerizates. The present invention relates to the use of special mixtures of one-component polyurethanes, optionally vinyl copolymers and diene graft copolymers for coating textile fabrics.

Mixtures of segmented, essentially linear polyurethanes from higher molecular weight dihydroxyl compounds, aromatic diisocyanates and dialcohols as chain extenders, vinyl copolymers and diene graft copolymers to coatings with surprisingly significantly improved light fastness and Lightfastness.

It has been part of the state of the art for a long time, textiles such as Woven, knitted and nonwovens with solutions of polyester urethanes after direct or reverse process to coat. The articles obtained become manufacturing of outerwear, upholstery, bags, shoe uppers, tarpaulins, Used awnings and many other products.

In contrast to the two-component polyurethanes that have been known for a long time The so-called one-component polyurethanes are the newer state of the art. These Products are made by reacting polyhydroxyl compounds, in practice all dihydroxy polyesters or dihydroxy polyethers mixed with glycols, preferably Ethylene glycol or butanediol-1.4, with aromatic diisocyanates, preferably 4,4'-diphenylmethane diisocyanate, obtain. These can be produced both in the melt and in solution, essentially linear polyurethanes are only soluble in solvent mixtures, which are dimethylformamide or other highly polar compounds such as dimethylacetamide or N-methylpyrrolidone in proportions of approx. 20 - 60%, based on the total solvent. the One-component polyurethane solutions have a practically unlimited pot life.

The film formation process in this case is merely a physical one Process that, in contrast to two-component polyurethanes, is not chemical Reaction is accompanied.

Polyurethanes made with the help of aromatic diisocyanates generally have poor lightfastness and lightfastness. It is also known to improve the properties of aromatic one- or two-component polyurethanes, Light stabilizers such as UV absorbers and antioxidants should also be used.

One-component polyurethanes are used to produce top coats and adhesive coats according to the reverse process as 20 to 3 above Solutions that are practical always contain dimethylformamide for reasons of solubility. About that In addition, polyurethane elastomers can also be produced using the melt extrusion process Laminate onto textile substrates, or as an aqueous dispersion or as Process dry sinter powder for the purpose of textile coating. The after However, the most widespread method in the prior art is coating by means of Solutions.

It has now been found that when using special mixtures from one-component polyurethanes, optionally vinyl copolymers and diene graft copolymers for the coating of textile fabrics, surprisingly, coatings with improved lightfastness and improved lightfastness can be obtained.

The present invention relates to a method for coating of textile fabrics with polyurethanes according to the reverse process, whereby one in a first stage on a separating support the solution of an essentially of reactive end group-free polyurethane applies as a top coat, the top coat dries, in a second stage an adhesive coating solution is applied to the top coat, the textile fabric is laminated, the solvent in a second drying cycle of the adhesive line evaporates and then the coated textile from the release liner takes off, characterized in that polymer mixtures are used as top coats, those from A) 50-90% by weight, based on total polymer, of essentially linear Polyurethanes made from high molecular weight dihydroxyl compounds (molecular weight 500 - 4000), aromatic diisocyanates and diols (molecular weight 62-450), B) o - 50% by weight of vinyl copolymers and C) 1 - 50% by weight of diene graft polymers are.

The polyurethanes A can by methods known per se in the Melt or in solution, and two both by the one-shot process as well as a prepolymer.

Suitable dihydroxy polyesters and / or dihydroxy polyethers are preferably those with molecular weights between 600 and 4000, particularly preferably between 800 and 2500.

The dihydroxy polyesters are made from one or more in a known manner Dicarboxylic acids with preferably at least 6 carbon atoms and one or more dihydric alcohols produced.

Instead of the free polycarboxylic acids, the corresponding Polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures of these can be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic Be natural and optionally substituted and / or unsaturated, for example by halogen atoms be. Examples include: succinic acid, pimelic acid, adipic acid, Suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, Phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Tetrachlorophthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutaric anhydride, Maleic acid, Maleic anhydride, fumaric acid, dimeric and trimeric fatty acids such as oleic acid, optionally as a mixture with monomeric fatty acids, dimethyl terephthalate or bis-glycol terephthalate. Aliphatic dicarboxylic acids are preferred, and adipic acid is particularly preferred.

The dihydric alcohols are e.g. ethylene glycol, propylene glycol- (1,2) and - (1,3), butylene glycol (1,4) and - (2,3), hexanediol (1,6), octanediol (1,8), neopentyl glycol, 1,4-bishydroxymethylcylohexane, 2-methyl-1,3-propanediol, also diethylene glycol, Triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, Dibutylene glycol and polybutylene glycols in question. Also polyesters from lactones, e.g. E-caprolactone or hydroxycarboxylic acids, e.g. E-hydroxycaproic acid, can be used.

In addition to such polyesters, those according to the invention are suitable for the production Polyurethanes to be used also include hydroxy polycarbonates, in particular those made from Hexanediol-1,6 and diaryl carbonates.

Also those containing two hydroxyl groups that come into consideration according to the invention Polyethers are those of the type known per se and are made, for example, by polymerization of epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with itself, e.g. in the presence of BF3, or by attachment these epoxides, optionally in a mixture or in succession, on starting components with reactive hydrogen atoms such as alcohols or amines, e.g. Water, ethylene glycol, Propylene glycol- (1,2) or - (1,3), 4,4'-dihydroxydiphenylpropane, aniline, ethanolamine or ethylenediamine produced.

Dihydroxybutylene glycol polyethers and dihydroxypropylene glycol polyethers are particularly preferred.

Starting components to be used according to the invention are also used aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic Polyisocyanates into consideration, such as those by W. Siefgen in Justus Liebig's Annalen der Chemie, 562, pages 75 to 136, are described, for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, Cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate, and any Mixtures of these isomers, l-methyl-2,6-diisocyanatocyclohexane, l-methyl-2,4-diisocyanatocyclohexane, 1-isocyanato-3,3, 5-trimethyl-5-isocyanatomethyl-cyclohexane, 2,4- and 2,6-hexahydrotolylene diisocyanate as well as any mixtures of these isomers, hexahydro-l 3- and / or 1,4-phenylene diisocyanate, Perhydro-2,4t- and / or -4,4'-diphenylmethane diisocyanate, 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate and any mixtures of these isomers, diphenylmethane-2,4'- and / or -4,4'-diisocyanate, napthylene-1,5-diisocyanate or 4,4'-diphenyl-dimethylmethane diisocyanate or mixtures of these compounds. 4,4'-Diphenylmethane diisocyanate is particularly suitable.

The low molecular weight diol components that act as chain extenders serve in the production of the polyurethanes to be used according to the invention preferably molecular weights of 62-450. According to the invention, there are the most varied Types of diol compounds in question, for example a) alkanediols such as ethylene glycol, Propylene glycol-1,3 and propylene glycol-1,2, butanediol-1,4, pentanediol-1,5, dimethylpropanediol-1,4 3 and 1,6-hexanediol; b) ether diols such as diethylene glycol, triethylene glycol or 1,4-phenylene bis (ß-hydroxyethyl ether); c) aminodiols such as N-methyldiethanolamine or N-methyldipropanolamine; d) Ester diols of the general formulas HO- (CH2) x -CO-O- (CH2) y -OH and HO- (CH2 -O-CO-R-CO-O- (CH2) -OH in which R is an alkylene or arylene radical with 1-10, preferably 2-6, to carbon atoms, x = 2-6 and y = 3-5, z. B. # -Hydroxybutyl - # - hydroxy-caproic acid ester, # -Hydroxyhexyl- # -hydroxybutyric acid ester, adipic acid (ß-hydroxyethyl) ester and Terephthalic acid bis (ß-hydroxyethyl) ester.

e) Diolurethanes of the general formula HO- (CH2) xO-CO-NH-R'-NH-CO-O- (CH2) x-OH in which R 'is an alkylene, cycloalkylene or arylene radical with 2-15, preferably 2-6 carbon atoms and x represent a number between 2 and 6, for example 1,6-hexamethylene-bis- (ß-hydroxyethyl urethane) or 4,4'-diphenylmethane-bis (g-hydroxybutyl urethane); f) diol ureas of the general formula in which R "is an alkylene, cycloalkylene or arylene radical with 2-15, preferably 2-9, carbon atoms, R"'= H or CH3 and x = 2.3, for example 4,4'-diphenylmethane bis - (ß-hydroxyethylurea) or the compound The vinyl copolymers (component B) to be used according to the invention are prepared by known processes. Styrene, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl acetate and acrylic and methacrylic esters of aliphatic alcohols with 1 to 6 carbon atoms serve as monomers for this purpose. The copolymer should contain at least two of the vinyl monomers in an amount of more than 1% by weight, preferably more than 10% by weight.

According to the invention, copolymers of styrene are particularly preferred those with acrylonitrile, the styrene content is between 50 and 99% by weight, preferably between 60 and 80% by weight. The molecular weight of the copolymers is between 50,000 and 500,000, preferably between 70,000 and 100,000.

The diene graft copolymers to be used according to the invention (component C) are also produced by known processes.

Suitable graft base polymers are, for example, polybutadiene, polyisoprene, Polychloroprene, trans-polypentenamer and others or mixtures of these compounds.

The monomers used for grafting onto the polyene include the following vinyl compounds into consideration: styrene, acrylonitrile, vinyl acetate and Acrylic and / or methacrylic acid esters. Graft copolymers are preferred according to the invention of styrene and acrylonitrile used as graft monomers on polybutadiene. The polybutadiene content is between 30 and 90% by weight, preferably between 40 and 70% by weight.

The proportion of the graft monomers in the total graft copolymer is between 10 and 70% by weight, preferably between 30 and 60% by weight. This amounts to Ratio of styrene: acrylonitrile preferably 2: 1 to 4: 1. The molecular weight of the Graft copolymers is between 50,000 and 500,000, preferably between 70,000 and 100,000.

The polymer mixtures to be used according to the invention as top coats contain 50-90% by weight, preferably 70-80% by weight, of the essentially linear Polyurethane (component A), 0-50% by weight, preferably 5-25% by weight, vinyl copolymers (Federation 1-50% by weight, preferably 5-25% by weight, diene graft copolymers (C).

The preferred use of the mixtures according to the invention for coating textile underlays come from solutions.

These solutions contain 20 - 40%, preferably 25 - 30% solids, in solvent mixtures containing dimethylformamide. Contains besides dimethylformamide the solutions preferably methyl ethyl ketone; but you can also with toluene, xylene, ethyl acetate, acetone, methyl isobutyl ketone, methyl glycol acetate, Ethyl glycol acetate, cyclohexanone, tetrahydrofuran etc. can be blended. It is but it is also possible to use the mixtures according to the invention by the methods of melt extrusion or to be applied to textile substrates as aqueous dispersions.

The adhesive coats, with the aid of which the top coats according to the invention are laminated with the textile carrier material, can in principle be the same as the top lines be built up.

In this case, however, it is also possible to use the polyurethanes A) alone to use. In addition to one-component polyurethanes, they are also according to the invention the two-component systems known per se are also suitable as adhesive coatings. It deals are generally mixtures of polyurethane prepolymers with terminal OH groups and a molecular weight of about 10,000 to 80,000, preferably 20,000 up to 50,000, polyisocyanates and optionally catalysts. Come as polyisocyanates in addition to the abovementioned also compounds with more than 2 NCO groups or also Reaction products of polyhydroxyl compounds with excess polyisocyanate in question e.g. a 75% solution in ethyl acetate of a polyisocyanate from trimethylolpropane and 2,4-tolylene diisocyanate with an NCO content of approx. 10 % and a solid tolylene diisocyanate content of less than 0.3%.

In the adhesive coating solutions based on two-component polyurethanes In addition, catalysts of the type known per se are often used, e.g. tertiary Amines like Triethylamine, tributylamine, N-methyl-morpholine, N-ethyl-morpholine, N-cocomorpholine, N, N, N ', N'-tetramethyl-ethylenediamine, 1,4-diaza-ticyclo- (2,2,2) -octane, N-methyl-N'-dimethylaminoethyl-piperaæin, N, N-dimethylbenzylamine, bis- (N, N-diethylaminoethyl) adipate, N, N-diethylbenzylamine, pentamethyldiethylenetriamine, N, N-dimethylcyclohexylamine, N, N, N ', N'-tetramethyl-1,3-butanediamine, N, N-dimethyl-ß-phenylethylamine, 1,2-dimethylimidazole, 2-methylimidazole.

Tertiary hydrogen atoms which are active with respect to isocyanate groups Amines are e.g. triethanolamine, triisopropanolamine, N-methyl-diethanolamine, N-ethyl-diethanolamine, N, N-dimethyl-ethanolamine, and their reaction products with alkylene oxides, such as Propylene oxide and / or ethylene oxide.

Silaamines with carbon-silicon bonds are also used as catalysts, as described, for example, in German patent specification 1 229 290, in question, e.g. 2,2,4-trimethyl-2-silamorpholine, 1,3-diethyiaminomethyl-tetramethyl-disiloxane.

According to the invention, organic metal compounds, in particular organic titanium compounds, can be used as catalysts.

Further representatives of catalysts to be used according to the invention as well as details about the mode of operation of the catalytic converters can be found in the plastics manual, Volume VII, edited by Vieweg and Höchtlen, Carl-Hanser-Verlag, Munich 1966, e.g. described on pages 96 to 102.

As a solvent for the adhesive coats, they all come from the top coats mentioned substances into consideration. Highly polar solvents such as dimethylformamide however, should be based on less than 70% by weight, preferably less than 50 gb on total solvent mix, be present.

The top coat solutions which are made up of those to be used according to the invention Mixtures exist, and the adhesive coating solutions can of course also contain pigments, Fillers and other auxiliaries, such as hydrolysis stabilizers, UV stabilizers, Anti-aging agents, polysiloxanes, crosslinkers and accelerators are added.

The coating of a textile according to the reverse process takes place in generally in the following way: On a coating machine, e.g. the top coat solution is doctored onto a release paper using a roller doctor blade.

After the first passage through the drying tunnel, the one at the entrance Air temperature of about 80 - 1000C and at the exit of about 120 - 1400c, the adhesive coating solution is applied in a second coating system or after the web has returned in in an analogous manner, the textile web is laminated and im The solvent mixture of the adhesive coating evaporates in the drying tunnel. When leaving the In the drying tunnel, the release paper and the coated fabric web become independent wound from each other.

In the examples, the increased lightfastness and lightfastness of the coating mixtures according to the invention composed of polyurethanes, vinyl copolymers and diene graft copolymers demonstrated. Unless otherwise stated, figures are to be understood as parts by weight or percentages by weight.

EXAMPLES General working method for coating: On a coating machine, release paper is applied by means of a roller doctor blade the top coat solution D is applied by a doctor blade; the application rate is 120 g / m2 solution. To a first passage through a drying tunnel with an air temperature at the entrance of 1000C and at the output of 1400C, the Adhesive coat solution H (120 g solution / m²) knife-coated in an analogous manner, the textile web, a roughened cotton duvet with a weight of 240 g square meter, laminated and the solvent mixture of the adhesive coating evaporates in the drying tunnel. When leaving of the drying tunnel, the release paper and the coated fabric web become independent wound from each other.

Example 1: The top coat solution; D 1 is a 30% plastic solution in dimethylformamide / methyl ethyl ketone (3: 2) with a viscosity of 12,000 cP 250C; it contains: 24.0, a polyurethane elastomer made from 2,250 g (1.0 mole) of one Polyesters of 1,4-butanediol and adipic acid, 216.0 g of 1,4-butanediol (2.4 mol) and the equivalent amount of 4,4'-diphenylmethane diisocyanate (850 g); 4.20% of a copolymer made of styrene and acrylonitrile with a mixing ratio of 72:28 and a molecular weight from about 100,000; 1.80, a butadiene graft copolymer made from 50% polybutadiene, 36% styrene and 14% acrylonitrile. (Molecular weight approx. 100,000); 42% dimethylformamide and 28% methyl ethyl ketone.

The top coat solution D 2 is a goat plastic solution in dimethylformamide / methyl ethyl ketone (3: 2) with a viscosity of 20,000 cP at 25 ° C; it contains: 21.0% of the in the polyester urethane used in the top coat solution D 1; 3.15% of that in the top coat solution D 1 used copolymers of styrene and acrylonitrile; 5.85 96 of the butadiene graft copolymer described in top coat solution D 1; 42 % Dimethylformamide and 28% methyl ethyl ketone.

The top coat solution D 3 (comparative test) is a 30% plastic solution in dimethylformamide / methyl ethyl ketone (3: 2) with a viscosity of 20,000 cP 250C; it contains: 30% of the polyester urethane of the coating solution D 1 42% dimethylformamide and 28% methyl ethyl ketone.

The adhesive coat solution H 1 is a 25% solution of a polyester urethane in dimethylformamide / methyl ethyl ketone (3: 7) with 7,000 cP at 250C, which is made from 1700 g (1.0 mol) of a mixed polyester of 1,6-hexanediol, neopentyl glycol and adipic acid , 135.0 g of 1,4-butanediol (1.5 mol) and the equivalent amount of 4,4-diphenylmethanediisocyanate (625 g) was built up. D 1 D 2 D 3 (comparison) Lightfastness (measured after 5 5 4 DIN 54 004) Tensile strength. (kp / cm) a) zero value b) after 400 hours the Xenotest 300 260 80 (DIN 54004) The lightfastness and, in particular, light resistance of films from top coat solutions D 1 and D 2 are considerably increased compared to those from top coat solution D 3, which contains no vinyl copolymer and no diene graft copolymer.

Example 2 The top coat solution D 4 is a 30% plastic solution in dimethylformamide / methyl ethyl ketone (1: 1) with a viscosity of 14,000 cP 250; it contains: 21.0% of a polyester urethane from 2000 g (1.0 mol) of a mixed polyester from ethylene glycol / 1,4-butanediol and adipic acid (molecular weight approx. 2000), 108.0 g (1.20 Moles) 1,4-butanediol, 141.6 g (1.20 moles) 1,6-hexanediol and an equivalent amount of 4,4'-diphenylmethane diisocyanate (850 g); 3.15% of that in top coat solution D 1 contained copolymers of styrene and acrylonitrile; 5.85% of that in the top coat solution D 1 contained butadiene graft copolymer; 35% dimethylformamide and 35% methyl ethyl ketone.

The top coat solution D 5 (comparison product) is a 3096 plastic solution in dimethylformamide / methyl ethyl ketone (1: 1) with a viscosity of 17,000 cP at 25 ° C; it contains: 30% of the polyester urethane described for top coat solution D 4; 35% dimethylformamide and 35% methyl ethyl ketone. D4 D5 Lightfastness (measured after 5 4 DIN 54 004) tensile strenght a) zero value Light resistance 380 390 age b) 400 hours Xenotest 270 60 (DIN 54004)

Claims (7)

Claims: 1) Process for coating flat textile structures with polyurethanes according to the reverse process, with one in a first stage on a separating carrier is the solution of an essentially free of reactive end groups Applying polyurethane as a top coat, the top coat dries, in a second Step applies an adhesive coat solution to the top coat, the textile fabric laminated, the solvent of the adhesive coating in a second drying cycle evaporates and then the coated textile lifts off the release carrier, thereby characterized in that polymer mixtures are used as top coats, which consist of A) 50-90% by weight, based on total polymer, of essentially linear polyurethanes from high molecular weight dihydroxyl compounds (molecular weight 500 - 4000), aromatic Diisocyanates and diols (molecular weight 62-450), B) 0-50% by weight of vinyl copolymers and C) 1 to 50% by weight of diene graft copolymers are composed. 2) Method according to claim 1, characterized in that as top coats Polymer mixtures from A) 70-80% by weight of essentially linear polyurethanes, B) 5-25% by weight of vinyl copolymers and C) 5-25% by weight of diene graft copolymers be used. 3) Method according to claim 1 and 2, characterized in that as Vinyl copolymers Copolymers of 50-99% by weight of styrene and 1-50% by weight of acrylonitrile be used. 4) Method according to claim 1 and 2, characterized in that as Vinyl copolymers copolymers of 60 - 80 wt. 5 'styrene and 20 - 40 wt. -5' Acrylonitrile can be used. 5) Method according to claim 1 to 4, characterized in that as Diene graft copolymers those with a butadiene content of 30-90% by weight are used will. 6) Method according to claim 1 to 4, characterized in that as Diene graft copolymers used with a butadiene content of 40-70% by weight will. 7) Method according to claim 1 to 4, characterized in that as Diene graft copolymers those made from 40-70% by weight 5 'butadiene and 30-60% by weight styrene / acrylonitrile can be used in a weight ratio of 2: 1 to 4: 1.