KR20220135859A - Manufacturing method of artificial leather - Google Patents

Abstract

The present invention relates to a manufacturing method of artificial leather. More specifically, the present invention relates to a manufacturing method of artificial leather which, in the case of manufacturing artificial leather or synthetic leather using a water-based polyurethane resin, has an effect of preventing the surface migration of water-based polyurethane, and at the same time, expresses excellent touch by forming a non-adhesive area between a substrate and the water-based polyurethane resin.

Description

Manufacturing method of artificial leather {Manufacturing method of artificial leather}

The present invention relates to a method for manufacturing artificial leather, and more particularly, having an effect of preventing surface migration of water-based polyurethane when manufacturing artificial leather or synthetic leather using a water-based polyurethane resin; At the same time, it relates to a manufacturing method of artificial leather in which excellent tactile feel is expressed by forming a non-adhesive region between a substrate and an aqueous polyurethane resin.

Conventional natural leather has been widely used as a fabric material for shoes, bags, and clothing due to its unique soft feel and appearance, but it is expensive, production is limited in that it is derived from animal skins, and also has irregular sizes and shapes. There was a problem with mass production.

In addition, as ethical issues related to animal rights arise, the demand for the development of artificial leather as a sustainable substitute to solve the above problems has been continuously expanded, and accordingly, artificial leather has been developed to have a texture and appearance similar to that of natural leather. Research is being done to improve it.

In general, it is known that artificial leather is manufactured by a dry method and a wet method.

The dry method manufactures artificial leather including a polymer resin film layer and an adhesive layer, and specifically, a polymer resin is applied on a release paper to form a polymer resin film, and an adhesive is applied on the polymer resin film, then the fiber It is a method of manufacturing artificial leather by bonding and compressing a substrate and then removing the release paper. However, the artificial leather manufactured through this dry method has low air permeability and hygroscopicity due to the low-porosity polymeric resin film and the adhesive layer, and the feel is not soft and hard. There is a problem in that the reproducibility is low in that it is formed depending on the

On the other hand, in the wet method, a solution in which a polymer resin is dissolved by a solvent is applied or impregnated on a substrate to be coated including fibers and fabrics, and a polymer resin is applied or impregnated on the substrate to be coated, and then the solvent is removed and the polymer resin It is a method of manufacturing artificial leather through the washing and drying steps of

Artificial leather manufactured by this wet method has advantages of good breathability and hygroscopicity due to the pores in the polymer resin formed in the solvent removal step, and has the advantage of being soft to the touch. , there is a problem that the process of recovering the organic solvent must be necessarily accompanied.

In order to improve the problems caused by the use of the conventional organic solvent, research on manufacturing artificial leather using water and a hydrophilic solvent has been recently attempted.

As a related prior art, Korean Patent No. 10-0352466 (published on September 11, 2002) relates to a manufacturing method of artificial leather using water-dispersed polyurethane including a steam process, and in detail, water-dispersed polyurethane resin , a solution containing sodium bicarbonate as a foaming agent and an inorganic salt, ethyl alcohol, dimethylformamide (DMF) and a water-dispersed toner are impregnated into the textile substrate, and dried through steam spraying in the air to artificial leather In addition, Korean Patent Application Laid-Open No. 10-2020-0078345 (published on July 1, 2020) relates to a method for manufacturing artificial leather (leather material), and in detail, water-based polyurethane resin , a foaming agent, a formic acid ester compound, and a mixture containing water are impregnated into a fiber base material and then dried by heating to manufacture artificial leather.

However, the artificial leather manufactured from the prior documents uses water as a solvent for a mixed solution containing aqueous polyurethane. A migration phenomenon moving to the surface layer may occur frequently. In this case, when migration occurs, the aqueous polyurethane in the artificial leather is localized on the surface of the substrate to be coated and hardly exists therein, so the artificial leather There is a problem in that the feel of the skin becomes hard and wrinkles are easy to fold.

In addition, in the artificial leather manufactured from the preceding documents, in order to form a foamed structure in the aqueous polyurethane resin, a foaming agent must be necessarily included in the solution impregnating the fiber base, otherwise the artificial leather has a poor feel. Including a problem, in addition, when using an organic solvent such as DMF contained in the solution impregnating the fiber base, it may be absorbed into the skin and body and may be harmful, and contains environmental problems, thereby improving the above problems. There is a need to develop a manufacturing method for artificial leather.

Korean Patent No. 10-0352466 (Announcement Date: 2002.09.11.) Korea Patent Publication No. 10-2020-0078345 (published date: 2020.07.01.)

The present invention can prevent the migration phenomenon that occurs frequently in the manufacturing method of artificial leather obtained by impregnating the mixed solution containing water-based polyurethane and water according to the prior art to the substrate to be coated, and at the same time, it is possible to prevent migration between the substrate and the water-based poly It is an object of the present invention to provide a method for manufacturing artificial leather in which excellent tactile feel is expressed by forming non-adhesive regions between urethane resins.

In addition, the mixed solution impregnated into the base material to be coated, such as fibers, may have improved physical properties compared to the prior art without including a foaming agent and/or a foaming agent-related component that neutralizes the foaming agent or facilitates foaming, and also, the fibers Another object of the present invention is to provide a more eco-friendly, artificial leather manufacturing method since the mixed solution impregnated into the substrate does not contain organic solvents or foaming agent-related components that may cause human toxicity.

The manufacturing method of artificial leather according to the present invention comprises the steps of: a) impregnating a substrate to be coated with a mixed solution containing aqueous polyurethane and water; b) contacting at least a portion of the surface of the substrate to be coated, which is impregnated with the mixed solution obtained in step a), with a solution containing a decomposing acid that generates an acidic substance by heating; and c) heating the substrate to be coated, which has been contacted with the solution containing the decomposing acid that generates an acidic substance by heating, obtained in step b); includes

In one embodiment, the decomposed acid is an organic acid monohydric ester, an organic acid ester having 1 to 30 carbon atoms, an organic acid ester having 1 to 30 carbon atoms, an organic acid ester containing at least one ester group derived from a dihydric alcohol having 1 to 30 carbon atoms, and 1 carbon atom Derived from a trihydric alcohol of 30 to 30, an organic acid ester containing at least one ester group, an organic acid ester containing at least one ester group derived from a tetrahydric alcohol having 1 to 30 carbon atoms, a polyethylene glycol having 4 to 100 carbon atoms, It may include at least one of an organic acid ester including at least one ester group, an organic acid alkali metal salt, an organic acid alkaline earth metal salt, an organic acid ammonium salt, an organic acid quaternary amine salt, an inorganic acid ammonium salt, and mixtures thereof, wherein the organic acid has 1 carbon number to 30 carboxylic acids.

As a more preferable component of the decomposition acid, the decomposition acid is an organic acid ester, wherein the alcohol moiety is a monohydric alcohol having 1 to 10 carbon atoms, the alcohol moiety is a dihydric alcohol having 1 to 10 carbon atoms, and the alcohol moiety is 1 to 10 carbon atoms It may be a formic acid ester derived from one of the trihydric alcohols.

Here, as a more specific component of the decomposition acid, the decomposition acid is methyl formate, ethyl formate, butyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, ethylene glycol diformate. Mate, ethylene glycol diacetate, propylene glycol diacetate, polyethylene glycol monooleate, polyethylene glycol diolate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, trimethyl orthoformate, triethyl orthoformate, ammonium formate, ammonium acetate, diammonium maleate, diammonium hydro It may be at least one selected from gen citrate, ammonium citrate tribasic, ammonium polyacrylate, ammonium sulfate, ammonium carbonate, ammonium dihydrogen phosphate, diammonium phosphate, or a mixture thereof.

In one embodiment, in the step b), the contacting in the step of contacting the solution containing the decomposing acid to the surface of the substrate to be coated is the solution containing the decomposing acid that generates an acidic substance by heating the surface of the substrate to be coated. It can be achieved by spraying at least part of it.

As an embodiment, the heating of the coating target substrate contacted with the solution containing the decomposing acid in step c) may be heated so that the gelation temperature of the polyurethane in the coating target substrate is in the range of 20 to 100°C.

The present invention can also provide an artificial leather manufactured according to the manufacturing method of the artificial leather according to the present invention.

According to the artificial leather manufacturing method of the present invention, the migration phenomenon that occurs frequently in the manufacturing method of artificial leather obtained by impregnating the mixed solution containing water-based polyurethane and water according to the prior art to the substrate to be coated can be prevented. At the same time, it is possible to provide an artificial leather excellent in feel by forming a non-adhesive region between the base material and the water-based polyurethane resin.

In addition, since the mixed solution impregnated in the fiber base does not contain an organic solvent or foaming agent-related component that may cause human toxicity, it is possible to provide a more eco-friendly, artificial leather manufacturing method.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is those well known and commonly used in the art.

Throughout this specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

Hereinafter, in the specification of the present invention, the term 'decomposition acid' means that the original component is hydrolyzed or pyrolyzed in the presence of a catalyst or without a catalyst according to external heating or energy supply, resulting in the hydrolysis or thermal decomposition. It is defined as a compound whose decomposition products produce acidic substances. Here, the acidic material, which is a component produced by heating under the catalyst or non-catalyst of the decomposition acid, may have a pH of 7 or less when it is dissolved in an aqueous solution, and the decomposition acid which is a component before hydrolysis or thermal decomposition When dissolved in an aqueous solution and not heated, the pH of the solution in which the decomposed acid is dissolved may represent 7 or more.

The manufacturing method of artificial leather according to the present invention comprises the steps of: a) impregnating a substrate to be coated with a mixed solution containing aqueous polyurethane and water; b) contacting at least a portion of the surface of the substrate to be coated, which is impregnated with the mixed solution obtained in step a), with a solution containing a decomposing acid that generates an acidic substance by heating; and c) heating the substrate to be coated, which has been contacted with the solution containing the decomposing acid that generates an acidic substance by heating, obtained in step b); includes

According to the prior art, a method for producing artificial leather through a wet method using water as a solvent includes impregnating a substrate to be coated with a mixed solution containing aqueous polyurethane, a foaming agent and water, and performing a heating step as a subsequent step. , artificial leather can be manufactured using the principle that pores and foam structures are formed on the surface of the aqueous polyurethane film layer by carbon dioxide (CO ₂ ) generated from the foaming agent.

However, the present inventors have deviated from the method of manufacturing artificial leather, which must include the foaming agent in the prior art, and impregnated a mixed solution containing aqueous polyurethane and water into a substrate to be coated, such as a fiber (step (a)) After that, after contacting at least a portion of the surface of the substrate to be coated, which is impregnated with the mixed solution obtained in step a), with a solution containing a decomposing acid that generates an acidic substance by heating (step b)), the By heating the base material to be coated with the solution (step c)), migration that occurs frequently in the manufacturing method of artificial leather obtained by impregnating the mixed solution containing water-based polyurethane and water according to the prior art to the base material to be coated The present invention has been completed by discovering that it is possible to prevent development and provide an artificial leather excellent in feel.

Hereinafter, each step configuration according to the artificial leather manufacturing method of the present invention will be described in detail.

As a first step, step a) is a step of impregnating the coating target substrate with a mixed solution containing aqueous polyurethane and water;

Here, the coating target substrate is a component coated with an artificial leather coating layer containing aqueous polyurethane, and the coating target substrate is a fiber, yarn, fabric, cloth, fabric, circular knitted fabric, tricot, nonwoven fabric, etc. as described above. It is not limited to, and it can be used without limitation as long as it is a material that can be coated with a mixed solution containing an aqueous polyurethane regardless of component, shape, shape and weaving aspect, but it can imitate the breathability and hygroscopicity of natural leather. A nonwoven fabric including a network structure can be preferably used so as to be.

In addition, the material of the base material to be coated, such as such fibers, is not particularly limited, but polyamide fibers and polyester fibers are preferable from the viewpoints of a sufficient thickness and a feeling close to natural leather and quality.

In addition, in impregnating the coating target substrate with the mixed solution containing the aqueous polyurethane and water, it is preferable to sufficiently impregnate the resulting artificial leather so that the component derived from the aqueous polyurethane resin adheres to the inside.

On the other hand, the aqueous polyurethane is a resin component included in the film layer of artificial leather, and does not contain a hydrophilic functional group in the structure in a water-soluble solvent environment, so that it can be artificially emulsified by adding an emulsifier. It is classified as a self-emulsifying water-based polyurethane resin that can self-emulsify including a hydrophilic functional group.

As for the forced emulsification type aqueous polyurethane resin and self-emulsifying type aqueous polyurethane resin, conventionally known components may be used without limitation, and conventionally known components may be used without limitation as an emulsifier.

<Forced emulsification type water-based polyurethane>

As an embodiment of the present invention, the forced emulsification type aqueous polyurethane, which is a heat-sensitive coagulation type urethane resin, is first reacted with a polyol and a polyisocyanate selectively with a chain extender having two or more active hydrogen atoms to obtain an isocyanate group-terminated prepolymer. Then, the prepolymer is forcibly emulsified and dispersed in water using a nonionic surfactant of HLB 7 to 16, and then the one obtained by chain extension reaction with a polyamine compound containing two or more amino groups and/or imino groups can be used. have.

The HLB (Hydrophile-Lipophile Balance) of the nonionic surfactant is an index indicating the degree of hydrophilicity and lipophilicity of the surfactant calculated by Griffin's formula. The closer the HLB value is to 0, the higher the lipophilicity or hydrophobicity, and the The closer the HLB value to 20, the higher the hydrophilicity.

The polyol may include, but is not limited to, a polyester polyol having two or more hydroxyl groups, a polycarbonate polyol, and a polyether polyol.

The polyester polyol is polyethylene adipate, polybutylene adipate, polyethylenebutylene adipate, polyhexamethylene isophthalate adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, poly -ε caprolactone diol, poly(3-methyl-1,5-pentylene) adipate, polycondensate of 1,6-hexanediol and dimer acid, co-condensation of 1,6-hexanediol, adipic acid and dimer acid Water, a polycondensate of nonanediol and dimer acid, and a copolymer of ethylene glycol and adipic acid and dimer acid may be used without limitation.

The polycarbonate polyol may include, but is not limited to, polytetramethylene carbonate diol, polyhexamethylene carbonate diol, poly-1,4-cyclohexanedimethylene carbonate diol, and the like.

The polyether polyol has a molecular weight of 200 to 6,000 polyethylene glycol, polypropylene glycol, polytetramethylene glycol homopolymer, block copolymer and random copolymer, ethylene oxide and propylene oxide, ethylene oxide and butylene oxide random copolymer or Block copolymers and the like may be used without limitation.

In addition, as the polyol, a polyether ester polyol having an ether bond and an ester bond may be used, and in this case, the polyol may be used alone or in combination of two or more.

As the polyisocyanate, aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate having two or more isocyanate groups may be used, and as a specific example, aliphatic polyisocyanate compounds such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate, isophorone Alicyclic polyisocyanate, such as diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1, 3-bis (isocyanate methyl) cyclohexane, torylene diisocyanate, diphenylmethane diisocyanate, naphthalene Aromatic polyisocyanates such as diisocyanate, triidine diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate can be used without limitation. The said polyisocyanate compound can be used individually by 1 type or in combination of 2 or more types.

Among the polyisocyanate compounds, aliphatic polyisocyanate and alicyclic polyisocyanate compounds are preferable from the viewpoint of providing a non-yellowing film, for example, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, nor Bornanediisocyanate and 1,3-bis(isocyanatemethyl)cyclohexane can be preferably used. More preferably, dicyclohexylmethane diisocyanate having excellent light resistance and heat resistance may be used.

The chain extender having two or more active hydrogen atoms may be optionally used, and specific examples of the chain extender include ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, Low molecular weight polyhydric alcohols such as trimethylolpropane, pentaerythritol and sorbitol, ethylenediamine, propylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine, diethylenetriamine, triamine Low molecular weight polyamines such as ethylenetetramine may be used without limitation. The chain extender may be used alone or in combination of two or more.

The production method of the isocyanate group-terminated prepolymer is not limited to a specific method, and a known production method such as a one-shot polyisocyanate polyaddition reaction method or a multistage isocyanate polyaddition reaction method can be used.

The reaction temperature for synthesizing the isocyanate group-terminated prepolymer is preferably 40 to 150°C.

In addition, in the reaction solution for synthesizing the isocyanate group-terminated prepolymer, dibutyltin dilaurate, stanasoctoate, dibutyltin-2-ethylhexanoate, triethylamine, triethylenediamine, N-methylmorpholine A reaction catalyst such as these may be added.

In addition, an organic solvent that does not react with the isocyanate group may be added to the reaction solution for synthesizing the isocyanate group-terminated prepolymer during the reaction or after the completion of the reaction.

As a specific example, the organic solvent may include, but is not limited to, acetone, methyl ethyl ketone, toluene, tetrahydrofuran, dioxane, dimethylformamide, N-methylpyrrolidone, and the like. However, since the organic solvent is preferably removed by distillation under reduced pressure after the chain extension reaction is completed, acetone, methyl ethyl ketone, or tetrahydrofuran may be preferably used.

In one embodiment of the present invention, when the isocyanate-terminated prepolymer is dispersed in water, a nonionic surfactant of HLB 7 to 16, preferably a nonionic surfactant of HLB 9 to 15 may be used. In addition, the said HLB is HLB of the whole nonionic surfactant, and when many nonionic surfactants are used, the weighted average is meant. If the HLB of the nonionic surfactant used is less than 7, the emulsified dispersion is not stable, and if the HLB of the nonionic surfactant exceeds 16, the aqueous polyurethane composition is impregnated or applied to the foam, and then immersed in warm water , there is a problem that the urethane resin dispersion is eluted.

As the nonionic surfactant used for dispersing the isocyanate-terminated prepolymer in water, a known nonionic surfactant may be used without limitation as long as it is in the range of HLB 7 to 16, and as a specific example, polyoxyethylene distyrylphenyl ether type Nonionic surfactant, polyoxyethyleneoxypropylene distyrylphenyl ether type nonionic surfactant, polyoxyethylene tristyrylphenyl ether type nonionic surfactant, polyoxyethyleneoxypropylene tristyrylphenyl ether type nonionic surfactant; polyoxyethylene long-chain alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene sorbitol tetraoleate or the like, or block or random polymers of polyoxypropylene/polyoxyethylene glycol, polyoxypropylene/polyoxyethylene adducts of polyamines and the like can be used.

In particular, the nonionic surfactant preferably has a skeleton of the following formula (I).

[Formula 1]

(R-) _n Ph-O(AO) _m H

In the above [Formula 1], R is an alkyl group, aryl group, or arylalkyl group having 1 to 9 carbon atoms, n is an integer of 1 to 3, Ph is a phenyl ring residue, AO is oxyethylene and / or oxypropylene, m is the AO added moles.

The said nonionic surfactant can be used individually by 1 type or in combination of 2 or more types.

The amount of the nonionic surfactant used is not particularly limited, but is preferably 0.5 to 10 mass%, more preferably 1 to 6 mass%, based on 100 mass% of the total isocyanate-terminated prepolymer. If the amount of the nonionic surfactant is less than 0.5% by mass relative to the isocyanate-terminated prepolymer, there is a problem that a stable emulsified and dispersed state cannot be obtained. Or there is a problem that it is easily removed during washing.

When the isocyanate group-terminated prepolymer is emulsified and dispersed in water, mechanical shearing force can be used. There is no restriction|limiting in particular as a means for providing a mechanical shearing force, For example, emulsification equipment, such as a homomixer and a homogenizer, can be used.

It is preferable that the isocyanate group terminal prepolymer is emulsified and dispersed in water in a temperature range of 5 to 40°C to suppress the reaction of the isocyanate group with water or a nonionic surfactant.

In addition, when the isocyanate group-terminated prepolymer is emulsified and dispersed in water, a reaction inhibitor such as phosphoric acid, sodium dihydrogenphosphate, disodium hydrogenphosphate, paratoluenesulfonic acid, adipic acid, or benzoyl chloride may be optionally added.

After emulsifying and dispersing the isocyanate group-terminated prepolymer in water, a chain extension reaction is carried out using a polyamine compound containing two or more amino groups and/or imino groups, whereby an aqueous urethane resin product is obtained.

The polyamine compound including two or more amino groups and/or imino groups is a specific example, ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, diaminocyclohexylmethane, piperazine, hydrazine, 2-methylpiperazine Diamines such as isophorone diamine, norbornanediamine, diaminodiphenylmethane, torylenediamine, and xylylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, tris Polyamines such as (2-aminoethyl)amine, amidamines derived from primary amines and monocarboxylic acids, water-soluble amine derivatives such as monoketimine of primary amines, dihydrazide oxalate, dihydrazide meronate, di succinate Hydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, 1,1'-ethylene Hydrazine derivatives such as hydrazine, 1,1'-trimethylenehydrazine, and 1,1'-(1,4-butylene)dihydrazine can be used. The polyamine compound and the amine derivative may be used alone or in combination of two or more.

The chain extension reaction of the isocyanate group-terminated prepolymer can be carried out by adding a polyamine compound to the emulsified dispersion of the isocyanate group-terminated prepolymer or by adding an emulsified dispersion of the prepolymer to the polyamine compound.

It is preferable to carry out the said chain extension reaction at the reaction temperature of 20-40 degreeC. When an organic solvent is used in the synthesis of the isocyanate group-terminated prepolymer, it is preferable to remove the organic solvent by distillation under reduced pressure or the like after the chain extension reaction is completed.

When an organic solvent is used for the chain extension reaction, a substantially solvent-free aqueous dispersion having a solid content of about 10 to 60 mass %, preferably 15 to 50 mass %, is obtained through a step of removing the organic solvent. do.

The aqueous polyurethane can exhibit excellent heat-sensitive coagulation property by combination with the water-soluble acrylic polymer, and preferably has an average particle diameter of at least 0.1 µm or more from the viewpoint of preventing migration during drying. When the average particle diameter of the aqueous polyurethane is less than 0.1 µm, there is a problem in that the migration prevention properties are lowered. Moreover, it is more preferable that the average particle diameter of the said aqueous polyurethane is 0.15-5 micrometers. When the average particle diameter of the urethane resin is 5 µm or more, there is a problem that the stability of the aqueous polyurethane decreases.

The 'average particle diameter' in the specification of the present invention is the median diameter when measured on a volume basis using "LA-920", a laser diffraction/scattering type particle size distribution measuring device (refer to: Horibase, Inc.) points to

<Self-emulsifying water-based polyurethane>

As another example of the present invention, the aqueous polyurethane, which is a self-emulsifying water-based polyurethane resin, is an aqueous polyurethane having an anionic group in the resin backbone, and a water-emulsified dispersion in which the aqueous polyurethane concentration in water is 40% by mass is 20 ° C. It is preferable that it is an aqueous polyurethane in which no separation or settling is observed even after standing for 12 hours in a vacuum.

The anionic group may be a carboxy group, a carboxylate group, a sulfo group and a sulfonate group. The self-emulsifying aqueous polyurethane is preferably an aqueous polyurethane having at least one anionic group selected from the group consisting of a carboxyl group, a carboxylate group, a sulfo group and a sulfonate group from the viewpoint of excellent emulsion dispersion stability, a carboxyl group and It is more preferable that it is a polyurethane resin which has/or a carboxylate group, or an aqueous|water-based polyurethane which has a sulfo group and/or a sulfonate group.

The content of the anionic group in the self-emulsifying aqueous polyurethane is preferably 0.1 to 5.0 mass%, more preferably 0.2 to 2.5 mass%.

Further, (i) when the self-emulsifying aqueous polyurethane according to the present invention has a carboxyl group and/or a carboxylate group, the total content of the carboxyl group and the carboxylate group is more preferably 0.5 to 4.0 mass%, and 0.7 It is still more preferable that it is thru|or 2.5 mass %.

Further, when the self-emulsifying aqueous polyurethane resin has a sulfo group and/or a sulfonate group, the total content of the sulfo group and the sulfonate group is more preferably 0.1 to 1.0 mass%, and 0.2 to 1.0 mass%. it is even more preferable.

Further, when the self-emulsifying aqueous polyurethane has a carboxyl group and/or a carboxylate group, and a sulfo group and/or a sulfonate group, the total content of the carboxyl group and the carboxylate group is 0.1 to 4.0 mass%, and It is especially preferable that the total content of a sulfo group and a sulfonate group is 0.1-1.0 mass %.

When the content of the anionic group is less than the value described as the lower limit, there is a problem in that the storage stability of the aqueous self-emulsifying aqueous polyurethane dispersion is deteriorated. There is a problem in that the thermal coagulation temperature is high and the effect of inhibiting migration of the coating target substrate (a phenomenon in which the aqueous polyurethane migrates to the surface of the fiber substrate) is reduced.

As an example of the present invention, the self-emulsifying aqueous polyurethane is an isocyanate group-terminated prepolymer having a carboxylate group obtained from the reaction of a polyol, a polyisocyanate, and a compound containing a carboxyl group and two or more active hydrogens, by self-emulsification After emulsifying and dispersing in water, a polyurethane resin having a carboxyl group and/or a carboxylate group obtained by a chain extension reaction using a polyamine compound containing two or more amino groups and/or imino groups can be used.

As another example of the present invention, an isocyanate group-terminated prepolymer having a sulfonate group obtained through the reaction of a polyol, polyisocyanate, and a polyamine compound containing two or more amino and/or imino groups and a sulfo group and/or sulfonate group, A polyurethane resin having a sulfo group and/or a sulfonate group obtained by emulsifying and dispersing in water by self-emulsification and carrying out a chain extension reaction using a polyamine compound containing two or more amino groups and/or imino groups can be used.

The polyol, polyisocyanate and polyamine compound used in the method for producing the self-emulsifying water-based polyurethane can be used in the same way as the polyol, polyisocyanate and polyamine compound used in the method for preparing the forced-emulsifying water-based polyurethane. to be omitted.

The aqueous polyurethane component according to the present invention is preferably at least one selected from the group consisting of a self-emulsifying aqueous polyurethane resin having a hydrophilic functional group and a forced emulsifying aqueous polyurethane resin not containing a hydrophilic functional group, mixed It may be included in an amount of 5 to 90 wt%, preferably 10 to 70 wt%, based on the solid content based on 100 wt% of the total solution.

In addition, the water corresponds to a component that provides an aqueous solvent environment of the mixed solution containing the aqueous polyurethane. This is an alternative to the organic solvent, which is the solvent used in the wet method in the prior art, and as a solvent that is harmless to the human body and the environment compared to organic solvents, and does not require a separate recovery treatment, it enables the manufacture of eco-friendly artificial leather. Here, the water may be included in an amount of 5 to 90 wt%, preferably 10 to 70 wt%, based on 100 wt% of the total mixed solution.

In addition, the mixed solution in step a) is a solution containing aqueous polyurethane and water, may additionally contain a surfactant, and is a component for finally impregnating the aqueous polyurethane into the substrate to be coated.

The content ratio of aqueous polyurethane and water in the mixed solution of step a) in the present invention may be mixed in the range of 9:1 to 1:9 with respect to each weight of polyurethane solid content and water.

With respect to the content ratio of the aqueous polyurethane and water, if the content of the aqueous polyurethane is further increased based on the ratio of 9:1, the viscosity of the mixed solution is excessive and there is a problem that the degree of impregnation into the substrate to be coated is low, When the content of water is further increased based on the content ratio of 1:9, the above range is preferable because there is a problem that the aqueous polyurethane is insufficiently impregnated or coated on the substrate to be coated.

In addition, the impregnation of the coating target substrate may be performed by immersing the coating target substrate in one or more impregnation tanks containing a mixed solution or by immersing the coating target substrate therein using a roll to roll process. The present invention is not limited thereto, and known impregnation methods and accompanying machines and devices may be used.

On the other hand, step b) in the present invention is a step of contacting at least a portion of the surface of the substrate to be coated, which is impregnated with the mixed solution obtained in step a), with a solution containing a decomposing acid that generates an acidic substance by heating. As, for example, the coating target substrate is immersed in one or more impregnation tanks containing the mixed solution in step a), or the coating target substrate discharged after impregnation using a roll to roll process is acidified by heating. A solution comprising a decomposing acid that produces a substance may be brought into contact with at least a portion of the surface of the substrate to be coated.

Here, the configuration in which the solution containing the decomposing acid that generates an acidic material by heating is brought into contact with the substrate to be coated, which is impregnated with the mixed solution in step a), and then heated is a configuration corresponding to the technical characteristics of the present invention. , through this, the coating object impregnated with water and polyurethane components, rather than performing the thermal coagulation step through heating followed by the impregnation step of the coating target substrate by the mixed solution containing the foaming agent or decomposing acid in the prior art After the substrate is taken out from the impregnation tank, the step of contacting the decomposition acid with the surface is separately performed, and the generation of acidic material and the gelation of polyurethane according to its heating Through the steps, it has the effect of preventing the phenomenon of migration in the manufacturing process of artificial leather using water-based polyurethane.

In addition, the present invention provides a foaming agent component such as sodium hydrogen carbonate and sodium carbonate used for the purpose of forming pores and foam structures in the prior art through contact and heating of the decomposition acid after impregnation of the mixed solution with the substrate to be coated. It is possible to prevent migration and improve the feel of artificial leather without including it.

Here, the decomposition acid is, as described above, the original component is hydrolyzed or pyrolyzed in the presence of a catalyst or without a catalyst according to external heating or energy supply, so that the decomposition product produced according to the hydrolysis or thermal decomposition is acidic. It can be defined as a compound made of a substance, and an acidic substance, which is a component produced by heating a solution containing the decomposed acid under a catalyst or without a catalyst, prevents migration and provides an excellent tactile effect in the film layer composed of an aqueous polyurethane resin. can indicate

In addition, according to the present invention, the solution containing the decomposing acid may be a solution containing a decomposing acid component that is dissolved in water and has a pH of 7 or higher, and the solution is due to the decomposition of the decomposing acid component by heating. It will produce acidic material, so that the pH can be reduced below 7 after the solution is heated. In addition, as another example of the solution containing the decomposition acid, it may be a solution in which a basic material is mixed with a decomposition acid component that is dissolved in water to have a pH of 7 or less, in which case the solution containing the decomposition acid is heated As the decomposed acid produces acidic substances, the pH of the solution after heating can be lowered to 7 or less.

In one embodiment, the decomposed acid according to the present invention is an organic acid monohydric ester, and the monohydric alcohol moiety is derived from an organic acid ester having 1 to 30 carbon atoms or a dihydric alcohol having 1 to 30 carbon atoms, an organic acid containing at least one ester group. Esters, organic acid esters containing at least one ester group derived from trihydric alcohols having 1 to 30 carbon atoms, organic acid esters containing at least one ester group derived from tetrahydric alcohols having 1 to 30 carbon atoms, polyethylene having 4 to 100 carbon atoms It may include at least one of glycol-derived organic acid esters, organic acid alkali metal salts, organic acid alkaline earth metal salts, organic acid ammonium salts, organic acid quaternary amine salts, inorganic acid ammonium salts, and mixtures thereof including at least one ester group derived from glycol, wherein The organic acid means a carboxylic acid having 1 to 30 carbon atoms.

As a more preferable component of the decomposition acid, it is an organic acid monohydric ester, wherein the monohydric alcohol moiety contains at least one ester group derived from an organic acid ester having 1 to 10 carbon atoms or a dihydric alcohol having 1 to 10 carbon atoms. , derived from a trihydric alcohol having 1 to 10 carbon atoms, an organic acid ester containing at least one ester group, an organic acid ester containing at least one ester group derived from a tetrahydric alcohol having 1 to 10 carbon atoms, polyethylene glycol having 4 to 100 carbon atoms It may include at least one of an organic acid ester, an organic acid alkali metal salt, an organic acid alkaline earth metal salt, an organic acid ammonium salt, an organic acid quaternary amine salt, an inorganic acid ammonium salt, and a mixture thereof, wherein the organic acid means a carboxylic acid having 1 to 10 carbon atoms.

As a more preferable component of the decomposition acid, the decomposition acid is an organic acid ester, wherein the alcohol moiety is a monohydric alcohol having 1 to 10 carbon atoms, the alcohol moiety is a dihydric alcohol having 1 to 10 carbon atoms, and the alcohol moiety is 1 to 10 carbon atoms It may be a formic acid ester derived from one of the trihydric alcohols.

Here, as a more specific component of the decomposition acid, it is methyl formate, ethyl formate, butyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, ethylene glycol diformate, Ethylene glycol diacetate, propylene glycol diacetate, polyethylene glycol monooleate, polyethylene glycol diolate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl Ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, trimethyl orthoformate, triethyl orthoformate, ammonium formate, ammonium acetate, diammonium maleate, diammonium hydrogen sheet It may be at least one selected from lactate, ammonium citrate tribasic, ammonium polyacrylate, ammonium sulfate, ammonium carbonate, ammonium dihydrogen phosphate, and diammonium phosphate, or a mixture thereof.

Here, in the step b) according to the present invention, the solution containing the decomposing acid that generates an acidic substance by heating means the decomposition acid itself or a solution containing the decomposing acid, in this case, the decomposition acid is As the solvent in the containing solution, water or an aqueous solvent may be used.

That is, the decomposition acid may contain one of water and a water-soluble solvent or a mixture thereof in an amount of 0 to 95% by weight relative to 100% by weight of the total composition containing the decomposition acid, and the decomposition acid may be used as it is, or water and water-soluble One of the solvents or a mixture thereof may be used by diluting the decomposition acid.

On the other hand, in step b) of the present invention, in the step of contacting the solution containing the decomposition acid with at least a portion of the surface of the substrate to be coated with the mixed solution impregnated, the contacting includes a decomposition acid that generates an acidic substance by heating It can be made by spraying the solution to at least a portion of the surface of the substrate to be coated.

'Spraying' for the contact means an embodiment in which a solution containing a decomposing acid is dispersed in the air in the form of fine droplets and uniformly applied to at least a portion of the surface of the substrate to be coated, but is not limited thereto.

The contact by the spraying is a concept that includes all of the dispersion form or shape of the fine droplets dispersed in the air, the density of the microdroplets, and the number of times the microdroplets are sprayed, as long as they fall within the range that can be implemented by a known spraying technique.

That is, the solution containing the decomposition acid is included in the mixed solution together with the aqueous polyurethane component and is not impregnated with the substrate to be coated, and the acid component in the decomposition acid is generated by heating after contacting the substrate to be coated through a separate process. As a result, it exhibits the effect of preventing migration and providing a soft feel of artificial leather in the film layer made of the water-based polyurethane resin.

On the other hand, in the present invention, step c) is a step of heating the substrate to be coated in contact with the solution containing the decomposing acid that generates an acidic substance by heating obtained in step b), and in step b) The decomposed acid component in contact with the substrate is heated to generate an acidic substance, thereby preventing migration in the manufacturing process of artificial leather using water-based polyurethane.

In addition, the heating may be involved in the gelation of the polyurethane while at the same time generating an acidic substance of the decomposition acid. Here, the heating is performed so that the gelation temperature of the polyurethane in the substrate to be coated is in the range of 20 to 100 °C, preferably 30 to 100 °C, more preferably 40 to 100 °C, more preferably 45 to 100 °C. ℃, more preferably 50 ~ 100 ℃, more preferably in a temperature range of 55 ~ 100 ℃ so that the polyurethane is gelled. At this time, the temperature at which the polyurethane gelation starts is 30 ~ 100 ℃, preferably 40 ~ 90 ℃, more preferably 45 ~ 80 ℃, more preferably 45 ~ 70 ℃, more preferably 45 ~ 65 ℃ ℃, more preferably, in the temperature range of 50 to 60 ℃, it is possible to start the gelation of the polyurethane, and in addition, under the heating conditions, the original component of the decomposition acid is catalyzed or without a catalyst. can

When the gelation temperature of the polyurethane is less than 20 ° C, thermal decomposition of the decomposition acid is insufficient, and when it is more than 100 ° C, the water-based polyurethane migrates to the surface of the base material to be coated by water vapor evaporation, that is, the problem of migration There is this.

On the other hand, the present invention after step c), drying the heated substrate to be coated; may additionally include.

The drying may be, for example, a heat drying method performed accompanying the heating step of step c), and specific heat drying methods include dry heat drying using hot air, wet heat drying using high temperature steam, and microwave drying using microwave irradiation. However, it is not limited to the method described above.

The drying may be performed after the heating process by performing separately from the heating step of step c) as another example. As a drying method performed separately from heating, a natural drying method, a method of drying the surface by supplying a wind direction in the room temperature range, and a drying method using reduced pressure or a vacuum environment, but not limitedly, a known drying method may be used.

In addition, as another embodiment of the present invention, the mixed solution of step a) may optionally include a foaming agent that generates gas by heating and/or an acidic material. Here, after impregnating the coating target substrate with the mixed solution containing the foaming agent, the solution containing the decomposing acid is brought into contact with the impregnated coating target substrate, and then heated so that the coating target substrate containing the blowing agent is acidic. generated to prevent migration and at the same time form a foaming structure by a foaming agent, wherein the foaming agent is 0 to 50 wt%, preferably 0 to 10 wt%, more preferably based on 100 wt% of the total mixed solution 0 to 5 wt% may be included.

In addition, in the present invention, the mixed solution of step a) may additionally include at least one of a heat-sensitive gelling agent, a thickener, and a penetrating agent.

The heat-sensitive gelling agent may be selectively added to the mixed solution in view of the possibility of softening the texture of the artificial leather by suppressing the shrinkage of the foam structure during heating and/or drying.

The thermal gelling agent includes a sodium salt of an inorganic acid, an ammonium salt of an inorganic acid, and mixtures thereof, and the inorganic acid may be one of perchloric acid, carbonic acid, sulfuric acid, sulfuric acid, sulfurous acid, phosphoric acid, and nitric acid. As a preferred component of the heat-sensitive gelling agent, sodium sulfate (sodium saffron) can be used. The heat-sensitive gelling agent may be included in an amount of 0 to 2 wt%, preferably 0 to 1 wt%, more preferably 0 to 0.1 wt%, based on 100 wt% of the total mixed solution.

The thickener may be selectively added to the mixed solution in that the impregnation of the water-based polyurethane into the substrate to be coated is suppressed and the thickness of the substrate is sufficiently maintained, so that the artificial leather has a soft feel.

Specific examples of the thickener include cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl hydroxypropyl cellulose, and carboxymethyl cellulose; starch-based derivatives such as soluble starch, carboxymethyl starch, and methyl starch; Alginic acids, such as sodium alginate and alginate propylene glycol ester; Natural such as guar gum, carrageenan, galactan, gum arabic, locust bean gum, quince seed, tragacanth gum, pectin, mannan, starch, xanthan gum, dextran, succinoglucan, curdlan, hyaluronic acid and salts thereof polysaccharides; natural protein systems such as casein, gelatin, collagen, and albumin; Polyalkylene glycol, polyoxyethylene glycol distearic acid ester, myristoyl polyoxyethylene stearyl ether, polyoxyethylene sorbitan triisostearylate, polyoxyethylene methyl glucose (mono, di or tri) laurate, Polyoxyethylene methylglucose (mono, di or tri) myristate, polyoxyethylene methyl glucose (mono, di or tri) palmitate, polyoxyethylene methyl glucose (mono, di or tri) stearate, polyoxyethylene methyl glucose polyoxyalkylene-based nonionic polymers such as (mono, di or tri) isostearate and polyoxyethylene methyl glucose (mono, di or tri) oleate; Vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinylmethyl ether, polyurethane-based polymers, and mixtures thereof may be used, and hydroxyethyl cellulose may be preferably used. The thickener may be included in an amount of 0 to 10 wt% based on 100 wt% of the total mixed solution.

The penetrating agent is a component that is included in the solution containing the decomposing acid to facilitate penetration of the decomposing acid in the mixed solution on the substrate to be coated. Specific examples of the penetrant include lower alcohols, glycol-based solvents, alcohol-based nonionic surfactants, acetylene glycol-based special surfactants, silicone-based surfactants, fluorine-based surfactants, anionic surfactants, cationic surfactants, etc. Penetrant; may be used.

The present invention may provide an artificial leather manufactured by the method for manufacturing the artificial leather.

The artificial leather may be used without limitation in fields such as vehicles, furniture, medical care, shoes, bags, pockets, sandals, miscellaneous goods, and polishing.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not to be construed as being limited by these examples.

<Examples 1 to 10>

(1) Preparation of mixed solution

Examples 1 to 10 are based on 100 wt% of the total mixed solution, 45 wt% of aqueous polyurethane resin solids, 49 wt% of water, 6 wt% of black pigment, and optionally a blowing agent, a heat-sensitive gelling agent, a thickener, and a dye. After mixing as shown in Table 1, the mixture was stirred at room temperature at 300 rpm for 10 minutes to obtain a mixed solution. The thermal coagulation temperature of the mixed solution is 50 to 60 °C.

(2) Impregnation with the base material to be coated

Using a slit mangle, a PET nonwoven fabric having a width of 30 cm, a length of 25 cm, and a thickness of 1.8 mm, which is the substrate to be coated, is immersed in the impregnation bath containing the mixed solution for 10 seconds, and then the gap of the sling mangle is adjusted to obtain a pick-up rate (Wet Pick up). ) to 130%, thereby obtaining a substrate to be coated impregnated with the mixed solution.

(3) Injection of decomposed acid undiluted solution

After taking out the coating target substrate impregnated with the aqueous polyurethane component from the impregnation tank, a decomposed acid undiluted solution mixed with a decomposition acid and optionally a penetrant as shown in Table 1 below on the impregnated coating target substrate surface is applied to the nonwoven area It was sprayed so that 1 g per m ² remained on the surface of the nonwoven fabric. Here, in order to apply the same amount of the decomposed acid, the weight measurement operation was repeated after spraying and the spraying amount was adjusted.

(4) heating

Dry heat drying is performed at 150° C. for 5 to 7 minutes for the substrate to be coated onto which the decomposed acid undiluted solution is sprayed, so that the thermal gelation start temperature is 50 to 60° C., and the temperature is adjusted to achieve gelation within the above temperature range. The artificial leather to which the black pigment of Examples 1 to 10 was added was prepared.

<Comparative Example 1>

An artificial leather to which a black pigment was added was prepared in the same manner as in Examples 1 to 10, except that the step of (3) spraying the decomposed acid undiluted solution of the above Examples was not performed.

<Comparative Examples 2 to 4>

(3) In the spraying step of the decomposed acid undiluted solution of the above embodiments, the same amount of non-dissolved acid (glycolic acid, acetic acid or citric acid) stock solution was sprayed instead of the decomposed acid undiluted solution. A pigment-added artificial leather was prepared.

<Experimental Example 1> Migration measurement

For the artificial leather dyed black obtained in Examples and Comparative Examples, the state of filling of the aqueous polyurethane was visually evaluated by electron micrographs of the cross-sections of the artificial leather, and is shown in Table 2 below.

3: Water-based polyurethane filling the entire cross section of artificial leather.

2: There is little water-based polyurethane inside the artificial leather, and the resin is migrating to the surface of the artificial leather.

1: Most of the water-based polyurethane is migrating to the artificial leather surface.

<Experimental Example 2> Touch evaluation

The tactile feel of the artificial leathers obtained from Examples and Comparative Examples was evaluated according to the following criteria, and is shown in Table 2 below.

5: Soft, resilient and very rich feel

4: Soft, resilient and rich feel

3: Soft, slightly lacking in resilience and feel

2: Slightly rough and hard, like paper

1: Rough, hard, paper-like feel

evaluation item Example comparative example One 2 3 4 5 6 7 8 9 10 One 2 3 4 migration 3 3 3 3 3 3 3 3 3 3 One One One One touch 4 2 2 4 4 4 3 3 4 4 One One One One

According to Table 2, Examples 1 to 10, in which the decomposed acid stock solution was sprayed onto the PET nonwoven fabric impregnated with the mixed solution, were Comparative Example 1 in which the decomposed acid stock solution was not sprayed and Comparative Examples in which the non-decomposed acid (general acid) stock solution was sprayed. The texture and migration were good compared to 2 to 4.

As shown in Table 2, the artificial leathers prepared in Examples 1 to 10 according to the present invention prevented migration and exhibited superior tactile feel compared to the artificial leathers in Comparative Examples 1 to 4.

As a result, the artificial leather manufactured according to the present invention prevents migration by carrying out the step of contacting the surface of the base material to be coated with a solution containing a decomposing acid that generates an acidic material by heating, and a foaming agent is added to the mixed solution in the impregnation tank. It is judged that the application potential is high because it is possible to manufacture artificial leather having a touch similar to that of natural leather without inputting it.

Claims (6)

a) impregnating a substrate to be coated with a mixed solution containing aqueous polyurethane and water;
b) contacting at least a portion of the surface of the substrate to be coated, which is impregnated with the mixed solution obtained in step a), with a solution containing a decomposing acid that generates an acidic substance by heating; and
c) heating the substrate to be coated, which has been contacted with the solution containing the decomposing acid that generates an acidic substance by heating, obtained in step b); A manufacturing method of artificial leather comprising a.
The method of claim 1,
The decomposed acid is an organic acid monohydric ester, an organic acid ester having a monohydric alcohol moiety having 1 to 30 carbon atoms, an organic acid ester derived from a dihydric alcohol having 1 to 30 carbon atoms, an organic acid ester containing at least one ester group, a trivalent having 1 to 30 carbon atoms Alcohol-derived organic acid ester containing at least one ester group, C1-C30 tetrahydric alcohol-derived organic acid ester containing at least one ester group, C4-C100 polyethylene glycol-derived, at least one ester group A method for producing artificial leather, comprising at least one of an organic acid ester, an organic acid alkali metal salt, an organic acid alkaline earth metal salt, an organic acid ammonium salt, an organic acid quaternary amine salt, an inorganic acid ammonium salt, and a mixture thereof
Here, the organic acid means a carboxylic acid having 1 to 30 carbon atoms.
The method of claim 1,
The decomposed acid is an organic acid ester, wherein the alcohol moiety is a monohydric alcohol having 1 to 10 carbon atoms, the alcohol moiety is a dihydric alcohol having 1 to 10 carbon atoms, and the alcohol moiety is formic acid derived from one of a C 1 to C10 trihydric alcohol. ester
The method of claim 1,
The decomposing acid is methyl formate, ethyl formate, butyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, ethylene glycol diformate, ethylene glycol diacetate, propylene glycol diacetate Acetate, polyethylene glycol monooleate, polyethylene glycol diolate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether Acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, trimethyl orthoformate, triethyl orthoformate, ammonium formate, ammonium acetate, diammonium maleate, diammonium hydrogen citrate, ammonium citrate tribasic, A method for producing artificial leather, characterized in that at least one selected from ammonium polyacrylate, ammonium sulfate, ammonium carbonate, ammonium dihydrogen phosphate, and diammonium phosphate, or a mixture thereof.
According to claim 1,
In step b), the contacting in the step of contacting the solution containing the decomposing acid to the surface of the substrate to be coated sprays the solution containing the decomposition acid that generates an acidic substance by heating onto at least a portion of the surface of the substrate to be coated. A method of manufacturing artificial leather, characterized in that it is made by
The method of claim 1,
The method for producing artificial leather, characterized in that the heating of the coating target substrate contacted with the solution containing the decomposing acid in step c) is heated so that the gelation temperature of the polyurethane in the coating target substrate is in the range of 20 to 100° C. .