JP2015501393A - Textile coating method - Google Patents

Abstract

The present invention relates to a method for producing a coated textile product, wherein the textile substrate is first contacted with an aqueous dispersion comprising at least one inorganic salt and at least one modified cellulose.

Description

  The present invention relates to a method for producing a coated textile product, wherein the textile substrate is first contacted with an aqueous dispersion comprising at least one inorganic salt and at least one modified cellulose.

  It has hitherto been known to produce synthetic leather by coating textiles with plastic. For example, synthetic leather is used, inter alia, as a shoe upper member, for clothing articles, as a material for making heels, or in the upholstery field. Besides other plastics such as PVC, the primary paint used here is polyurethane. A generally known principle for coating textiles with polyurethane is described in W. Schroeer, Textilveredlung [textile finishing] 1987, 22 (12), pages 459-467. A description of the coagulation sedimentation method can also be found in “Water-permeable new materials”, Harro Traeubel, Springer Verlag, Berlin, Heidelberg, New York, 1999, ISBN 3-540-64946-8, pages 42-63. .

  The main methods used in the production of synthetic leather are the direct coating method, the transfer coating method (indirect coating) and the setting (wet) method. In contrast to the direct method, the coating material in the transfer method is applied to a temporary support, and in the subsequent lamination step, the film is bonded to the textile substrate and separated from the temporary support (release paper). The transfer method is preferably carried out with a textile substrate that does not have a high tensile stress during coating, or with a coarse cloth that is not particularly dense.

  In the setting method, the textile substrate is usually coated with a DMF solution containing polyurethane. In the second step, the coated substrate is passed through a DMF / water bath and the proportion of water is gradually increased. The precipitation of polyurethane and the formation of a porous film occur here. Here, the fact that DMF and water have excellent miscibility and DMF and water act as a solvent / non-solvent pair for polyurethane is utilized. Condensed polyurethane paints are used especially for high-quality synthetic leather because they have relatively good respiratory activity and leather feel. The basic principle of the setting method is based on the use of suitable solvent / non-solvent pairs for polyurethane. A great advantage of the setting method is that it is possible to obtain a porous and breathable synthetic leather with excellent leather feel. Examples include the synthetic leather brands Clarino (R) and Alcantara (R). The disadvantage of the condensation method is that it requires the use of large amounts of DMF as the organic solvent. In order to minimize employee exposure to DMF emissions during manufacturing, additional design measures must be taken, which means much less expense compared to the simpler method. In addition, post-treatment requires disposal or post-treatment of large amounts of DMF / water mixture. This is a problem because water and DMF form an azeotrope and can therefore only be separated by distillation with great effort.

W. Schroeer, Textilveredlung [Textile Finish] 1987, 22 (12), 459-467 `` New material with water vapor permeability '', Harro Traeubel, Springer Verlag, Berlin, Heidelberg, New York, 1999, ISBN 3-540-64946-8, pp. 42-63

  Thus, one object of the invention makes it possible to obtain a coated fiber product with good properties, for example feel, without having to use a toxicologically unacceptable solvent, for example DMF. It was to develop a method for coating textile substrates.

The above purpose is
a) contacting the textile substrate with an aqueous dispersion A comprising at least one inorganic salt and at least one modified cellulose;
b) contacting the textile substrate with an aqueous dispersion B comprising at least one polymer selected from the group consisting of polyacrylates and polybutadienes; and
c) Achieved by a method for producing a coated textile product comprising at least a precipitation step in or on the textile substrate of at least one polymer selected from the group consisting of polyacrylates and polybutadienes.

  In step a), the textile substrate is contacted with an aqueous solution comprising at least one inorganic salt and at least one modified cellulose.

  The inorganic salt is preferably a salt selected from the group comprising alkali metal salts and alkaline earth metal salts. Inorganic salts include alkali metal halides, alkali metal phosphates, alkali metal nitrates, alkali metal sulfates, alkali metal carbonates, alkali metal hydrogen carbonates, alkaline earth metal halides, alkaline earth metal nitrates, alkaline earths Particularly preferred are salts selected from the group consisting of alkali metal phosphates, alkaline earth metal sulfates, alkaline earth metal carbonates and alkaline earth metal hydrogen carbonates. Inorganic salts must be sodium chloride, potassium chloride, sodium sulfate, sodium carbonate, potassium sulfate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, magnesium chloride, magnesium sulfate, magnesium nitrate, calcium chloride, calcium nitrate or calcium sulfate Is very particularly preferred. The inorganic salt is more preferably calcium nitrate, magnesium nitrate, calcium chloride or magnesium chloride.

  Inorganic salts are preferably in an amount of 0.01 to 25% by weight, particularly preferably in an amount of 0.5 to 15% by weight and very particularly preferably in an amount of 0.5 to 10% by weight, based on the total amount of dispersion A. Present in dispersion A.

  The chemically modified cellulose is preferably a compound selected from the group consisting of alkylated cellulose, hydroxyalkylated cellulose and carboxyalkylated cellulose.

  The chemically modified cellulose may be a compound selected from the group consisting of methylcellulose, ethylcellulose, propylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose and carboxypropylcellulose. Particularly preferred.

  The chemically modified cellulose is very particularly preferably methylcellulose or ethylcellulose.

  The modified cellulose is preferably in an amount of 10 ppm to 5% by weight, particularly preferably in an amount of 100 ppm to 3% by weight and very particularly preferably in an amount of 400 ppm to 1.5% by weight, based on the total amount of dispersion A. Present in dispersion A.

  The textile substrate is preferably contacted with the aqueous dispersion A at room temperature for 2 to 4 minutes, particularly preferably 1 to 2 minutes, very particularly preferably 0.2 to 1 minute. For the purposes of the present invention, contacting means partial or complete immersion in the dispersion, preferably complete immersion, or application of the dispersion by hand coater, printing or spraying.

  After contacting with dispersion A, the textile substrate is preferably passed through a squeezer consisting of two rollers to remove excess dispersion A. Here, before the textile substrate is brought into contact with the dispersion B containing at least one polymer selected from the group consisting of polyacrylate and polybutadiene, the squeezing machine is configured so that the dispersion A is a base material (liquid uptake). It should preferably be set to remain in the textile substrate in an amount of 60 to 180% by weight, particularly preferably 70 to 140%, very particularly preferably 80 to 120%, based on the weight per unit area. Before the textile substrate can be contacted with the dispersion B containing at least one polymer selected from the group consisting of polyacrylates and polybutadienes, air, infrared, preferably 2 to 10 minutes, particularly preferably 1 to 5 minutes Or it is preferable to dry partially using a heat | fever cylinder.

  The polyacrylate and polybutadiene present in the dispersion B are not particularly limited as long as they are soluble in water.

  Polyacrylate polymers are prepared from hydroxyl group-containing monomers, “acidic” monomers, or monomers that contain neither acidic nor OH groups.

  Suitable hydroxyl group-containing monomers include hydroxyalkyl esters of acrylic acid or methacrylic acid, preferably having 2 to 4 carbon atoms in the alkyl group, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2 -Or 3-hydroxypropyl acrylate and methacrylate, isomeric hydroxybutyl acrylate and methacrylate, and mixtures of these monomers.

  Suitable “acidic” comonomers include olefinically unsaturated polymerizable compounds containing at least one carboxyl group and / or sulfonic acid group, such as monocarboxylic acids having a molecular weight of 72 to 207 which are olefinically unsaturated. Or dicarboxylic acid is mentioned. Specific examples include olefinically unsaturated compounds containing acrylic acid, methacrylic acid, maleic acid, itaconic acid, and sulfonic acid groups, such as 2-acrylamido-2-methylpropanesulfonic acid, and their olefinically Mention may be made of mixtures of unsaturated acids.

  A third group of olefinically unsaturated monomers that may be used in conjunction in the preparation of polyacrylate polymers includes olefinically unsaturated compounds that do not contain either acidic or hydroxyl groups. Specific examples include esters of acrylic acid or methacrylic acid having 1 to 18, preferably 1 to 8 carbon atoms in the alcohol group, such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate , N-butyl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, n-stearyl acrylate, methacrylates corresponding to these acrylates, styrene, alkyl-substituted styrene, butadiene, isoprene, acrylonitrile, methacrylonitrile, vinyl acetate, stearin Examples include vinyl acid as well as mixtures of these monomers. Comonomers containing epoxy groups, such as glycidyl acrylate or methacrylate, or monomers such as N-methoxymeth-acrylamide or N-methacrylamide may also be used in small amounts.

  The production of aqueous dispersions containing polyacrylates and / or polybutadienes is carried out by known free radical polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization. A free radical emulsion polymerization method in an aqueous medium is preferred.

  Continuous or discontinuous polymerization methods may be used. Specific examples of the discontinuous method are a batch method and a feed method, the latter being preferred. In the feed process, water is added alone or with an anionic emulsifier and optionally a part of a nonionic emulsifier and with a part of the monomer mixture and heated to the polymerization temperature. In the case of monomer addition, the polymerization is initiated by free radicals and the remaining monomer mixture is metered together with the initiator mixture and emulsifier over a period of 1-10 hours, preferably 3-6 hours. . If necessary, the reaction mixture is then post-activated in order to carry out the polymerization to a conversion of at least 99%.

  The emulsifier used may be anionic and / or nonionic. The anionic emulsifier contains a carboxylate group, a sulfate group, a sulfonate group, a phosphate group or a phosphonate group. The emulsifier preferably contains a carboxylate group, a sulfate group, a sulfonate group, a phosphate group or a phosphonate group. The emulsifier may have a low molecular weight or a high molecular weight. The latter is described, for example, in DE-A 3 806 066 and DE-A 1 953 349.

  Suitable anionic emulsifiers are long chain alcohols or substituted phenols, polyether chains bound to hydroxyl groups containing 2 to 100 ethylene oxide units, and sulfate or phosphate groups bound in the form of ester units. It was built from Ammonia or amine is a preferred neutralizing agent for non-esterified acid groups. The emulsifiers may be added to the emulsion batch individually or as a mixture.

  Suitable nonionic emulsifiers which may be used in combination with anionic emulsifiers are aliphatic, araliphatic, cycloaliphatic or aromatic carboxylic acids, alcohols, phenol derivatives and / or amines, ethylene oxide Reaction products with epoxides such as Specific examples include ethylene oxide and castor oil carboxylic acid and abietic acid; long-chain alcohols such as oleyl alcohol, lauryl alcohol and stearyl alcohol; and phenol derivatives such as substituted benzylphenol, phenylphenol and nonylphenol. And reaction products of long chain amines such as dodecylamine and stearylamine. Reaction products with ethylene oxide include oligoethers and / or polyethers having a degree of polymerization of 2-100, preferably 5-50.

  These emulsifiers are added in an amount of 0.1 to 10% by weight, based on the monomer mixture. Suitable co-solvents include water soluble and water insoluble solvents. Suitable co-solvents include aromatic compounds such as benzene, toluene, xylene and chlorobenzene; esters such as ethyl acetate, butyl acetate, methyl glycol acetate, ethyl glycol acetate and methoxypropyl acetate; butyl glycol, tetrahydrofuran, dioxane, Ethers such as ethyl glycol ether, and ethers of diglycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; trichloromonofluoroethane; and cyclic amides such as N-methyl-pyrrolidone and N-methylcaprolactam .

  Free radical initiated polymerization may be initiated by water soluble and water insoluble initiators or initiator systems whose radical decomposition half-life at temperatures between 10 ° C. and 100 ° C. is 0.5 seconds to 7 hours. .

In general, the polymerization is carried out in aqueous emulsions in the aforementioned temperature range, preferably between 30 ° C. and 90 ° C., under a pressure of 10 ³ to 2 × 10 ⁴ mbar. The exact polymerization temperature is determined by the type of initiator. These initiators are used in an amount of 0.05 to 6% by weight, based on the total amount of monomers.

  Suitable initiators include water-soluble and water-insoluble azo compounds such as azoisobutyronitrile or 4,4′-azo-bis- (4-cyanopentanoic acid); inorganic and organic peroxides such as peroxides. Dibenzoyl oxide, t-butyl perpivalate, t-butyl-per-2-ethylhexanoate, t-butyl perbenzoate, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide, dicyclohexyl dicarbonate, Dibenzyl peroxydicarbonate, sodium salt, potassium salt and ammonium salt of peroxodisulfuric acid, and hydrogen peroxide. Peroxodisulfate and hydrogen peroxide may be used in combination with a reducing agent such as sodium salt of formamidine sulfinic acid, ascorbic acid or polyalkylene polyamine. A significant decrease in the polymerization temperature is generally achieved by the above.

  Conventional regulators may be used to regulate the molecular weight of the polymer, including n-dodecyl mercaptan, t-dodecyl mercaptan, diisopropyl xanthogen disulfide, di (methylene-trimethylolpropane) xanthogen disulfide and thioglycol. . These regulators are added in amounts of up to 3% by weight, based on the monomer mixture.

  If necessary after completion of the polymerization reaction, a neutralizing agent is added to the polymer present in the aqueous dispersion to obtain a degree of neutralization of 30-100%, preferably 50-100%. An inorganic base, ammonia or amine is added as a neutralizing agent. Specific examples include inorganic bases such as sodium hydroxide and potassium hydroxide; and amines such as ammonia, trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine and triethanolamine. The neutralizing agent may be used in substoichiometric or excess stoichiometric amounts, resulting in the aforementioned contents of sulfonate and / or carboxylate groups, in particular carboxylate groups and the aforementioned acid values.

  If there is complete neutralization of any acidic groups that may be present, the result is an acid value of zero, and the content of sulfonate and / or carboxylate groups is the initial content of sulfonate and / or carboxyl groups. Equivalent to. Due to partial neutralization, the content of sulfonate groups and / or carboxylate groups corresponds to the amount of neutralizing agent used. The resulting aqueous dispersion has the aforementioned concentration and viscosity. The optional co-solvent may remain in the aqueous dispersion in the amounts described above or may be removed by distillation after the polymerization reaction.

A preferred polyacrylate-containing aqueous dispersion B is the dispersion sold under the trademark Primal® available from Rohm and Hass, Philadelphia, Pa., USA.
Suitable polybutadiene-containing aqueous dispersions B include Euderm®-Resin 40B and Euderm®-Resin 50B.

  In a further preferred embodiment, Dispersion B comprises at least one coagulant in addition to at least one polymer selected from the group consisting of polyacrylates and polybutadienes. The coagulant is a salt or acid, for example an ammonium salt of an organic acid, which causes the coagulation of at least one polymer selected from the group consisting of polyacrylates and polybutadienes under specific conditions such as a specific temperature. . These substances include chemical agents that produce acids, ie, substances that are not acids at room temperature but become acid after warming. Some examples of such compounds include ethylene glycol diacetate, ethylene glycol formate, diethylene glycol formate, triethyl citrate, monostearyl citrate and organic acid esters.

  The coagulant is preferably present in the composition in an amount of 1 to 10% by weight based on the solid content of Dispersant B.

  In order to achieve good sedimentation stability, the number average particle size of certain polyacrylate dispersions and polybutadiene dispersions, determined by laser correlation spectroscopy, is preferably less than 750 nm, particularly preferably less than 500 nm, very particularly preferably It is less than 400 nm.

  The method of achieving precipitation in or on the textile substrate depends largely on the chemical composition of the dispersion B used according to the invention and, if present, on the type of coagulant. For example, precipitation can be effected by evaporation coagulation or salt, acid or electrolyte coagulation.

  In general, precipitation is achieved by increasing the temperature. For example, a simple heat treatment with steam can be applied to a textile substrate, for example, at 100 to 110 ° C. for 1 to 10 seconds. This is particularly preferred when ammonium salts or organic acids are used as coagulants. On the other hand, when the above-mentioned chemicals that produce acids are used as coagulants, it is preferable to carry out precipitation formation as described in US 5,916,636, US 5,968,597, US 5,952,413 and US 6,040,393.

  Alternatively, solidification is caused by immersion in a salt solution. Solidification is preferably performed using an inorganic salt selected from the group consisting of alkali metal salts and alkaline earth metal salts. Inorganic salts include alkali metal halides, alkali metal nitrates, alkali metal phosphates, alkali metal sulfates, alkali metal carbonates, alkali metal hydrogen carbonates, alkaline earth metal halides, alkaline earth metal phosphates, Particularly preferred are salts selected from the group consisting of alkaline earth metal nitrates, alkaline earth metal sulfates, alkaline earth metal carbonates and alkaline earth metal hydrogen carbonates. The inorganic salt is very particularly preferably sodium chloride, potassium chloride, sodium sulfate, sodium carbonate, potassium sulfate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, magnesium chloride, magnesium sulfate, calcium chloride or calcium sulfate. Even more preferably, the inorganic salt is calcium chloride or magnesium chloride.

  Inorganic salts are preferably used in an amount of 1 to 25% by weight, particularly preferably 1 to 15% by weight and very particularly preferably 1 to 10% by weight, based on the total amount of salt solution. Present in solution.

  After the precipitate formation in step c), further steps such as drying or condensation are carried out if necessary.

  The textile substrate used is preferably a woven, knitted or non-woven fabric based on natural and / or synthetic fibers. The textile substrate is particularly preferably a nonwoven fabric (short fiber nonwoven fabric, microfiber nonwoven fabric, etc.).

  The textile substrate is preferably a fiber such as polyester, nylon (6 or 6,6), cotton, polyester / cotton blend, wool, ramie, spandex, glass, thermoplastic polyurethane (TPU), thermoplastic olefin (TPO) Can be formed from The textile substrate can have a bonded / mesh-like (knitted), woven or non-woven construction.

  Treat textile substrates with dyes, colorants, pigments, UV absorbers, plasticizers, recontaminants, lubricants, antioxidants, flame inhibitors, rheology agents and the like before or after coating However, it is preferable to perform the addition before coating.

  When an elastomer polymer is immersed in a predetermined nonwoven fabric to be condensed and then subjected to a normal coloring process, a suede-like synthetic leather having good characteristics is obtained.

  The invention therefore further relates to a coated textile product, preferably a synthetic leather, obtainable by the process according to the invention.

Claims (11)

at least
a) contacting the textile substrate with an aqueous dispersion A comprising at least one inorganic salt and at least one modified cellulose;
b) contacting the textile substrate with an aqueous dispersion B comprising at least one polymer selected from the group consisting of polyacrylates and polybutadienes; and
c) A method for producing a coated fiber product comprising a precipitation step in or on a textile substrate of at least one polymer selected from the group consisting of polyacrylate and polybutadiene.   2. The method according to claim 1, wherein the inorganic salt is a salt selected from the group consisting of an alkali metal salt and an alkaline earth metal salt.   The alkali metal salt is a salt selected from the group consisting of an alkali metal halide, an alkali metal nitrate, an alkali metal phosphate, an alkali metal sulfate, an alkali metal carbonate, and an alkali metal bicarbonate. The method described.   Alkaline earth metal salts include alkaline earth metal halides, alkaline earth metal nitrates, alkaline earth metal phosphates, alkaline earth metal sulfates, alkaline earth metal carbonates and alkaline earth metal hydrogen carbonates. 3. The method according to claim 2, wherein the salt is selected from the group consisting of:   The method according to claim 1, wherein the inorganic salt is present in the dispersion A in an amount of 0.01 to 25% by weight based on the total amount of the dispersion A.   The modified cellulose is a compound selected from the group consisting of methylcellulose, ethylcellulose, propylcellulose, hydroxy-methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxy-propylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose and carboxy-propylcellulose. The method according to 1.   The method according to claim 1, wherein the modified cellulose is present in the dispersion A in an amount of 10 ppm to 5% by weight based on the total amount of the dispersion A.   2. A method according to claim 1, characterized in that the textile substrate used is a woven, knitted or non-woven fabric based on natural and / or synthetic fibers.   2. At least one polymer selected from the group consisting of polyacrylates and polybutadienes is precipitated in step c) in a water-containing bath or using a temperature in the range from 80 to 120 ° C. The method described in 1.   A coated fiber product obtained by the method according to any one of claims 1 to 9.   11. The coated fiber product according to claim 10, wherein the coated fiber product is synthetic leather.