WO2005083022A1 - Aqueous polyurethane coating composition - Google Patents

Abstract

A coating of synthetic leathers or the like which is excellent in weather resistance, texture, appearance, coating workability and the like can be obtained by using a polyurethane which is obtained using a liquid polyol or a polyol having a low melting point.

Description

Aqueous polyurethane coating composition

Technical field

 The present invention relates to an aqueous polyurethane coating composition. More specifically, the present invention relates to a synthetic leather having excellent heat resistance, hydrolysis resistance, abrasion resistance, flexibility, and weather resistance.

Used for automotive seating, furniture seating, furnishings, sundries, clothing, and shoes 1

Aqueous polyurethane coating composition capable of forming a surface coating layer on leather

The

Background art

 Generally, synthetic leather is composed of a base material, an adhesive layer and a coating layer, and is excellent in texture and appearance. Therefore, polyurethane resin is widely used for the adhesive layer and the coating layer. Above all, the coating layer required not only the texture and appearance but also abrasion resistance, hydrolysis resistance, weather resistance, heat resistance, light resistance, etc., but none of the materials had physical properties that satisfied all.

 Polyurethane used for the synthetic leather film layer mainly comprises a polyol, a polyisocyanate, and a chain extender such as a short-chain diol or diamine. For example, in Japanese Patent Application Laid-Open No. 2-251683, a polytetramethylene glycol-based polyurethane or a polycarbonate-based polyurethane, or a hydroxy compound having 6 or more carbon atoms is reacted with a dibasic acid in the skin layer. A synthetic leather using a polyester-based polyurethane containing the obtained polyester as a polyol component, or a polyester-based polyurethane containing an ε-force prolactone-based polyester polyol or a polymethylvalerolactone-based polyester polyol as a component is described.

Polycarbonate polyurethane is the most excellent in abrasion resistance, heat resistance and heat resistance Although it has excellent water decomposability, it has a problem that the finish is hard and the texture is poor. Polyurethanes using ether-based polyols such as polytetramethylene dalichol have no problem with hydrolysis resistance and texture, but have poor heat resistance and weather resistance.On the other hand, due to the condensation reaction between short-chain diol and dibasic acid, The resulting polyester polyol or polyurethane using ε-force prolactone-based polyester polyol is excellent in texture, weather resistance and heat resistance, but has a problem of strong crystallinity and whitening at low temperatures.

 In recent years, in consideration of the environment, various synthetic resin paints and coating material compositions used in a wide range of industrial fields such as automobiles, electric / electronics, and construction have been made water-soluble. Polyurethane coating compositions have also been made aqueous, for example, Japanese Patent Application Laid-Open Nos. 2000-63746, 2000-34-233, and An aqueous polyurethane film coating composition using various polyol components is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-220122.

 However, the aqueous polyurethane coating composition described in the above publication is inferior in workability because the polyol used in the process of producing the polyurethane prepolymer has high solidity or high viscosity, and the obtained film is flexible. It has a problem that it is inferior in properties and becomes brittle at low temperatures.

 An object of the present invention is to provide an aqueous polyurethane coating composition for use in synthetic leather and the like which has excellent appearance and flexibility, and has excellent heat resistance, hydrolysis resistance, and light resistance, and does not whiten even at low temperatures. Is to provide. Disclosure of the invention

The present inventors have conducted intensive studies to solve the above problems, and as a result, by using a liquid component or a low melting point polyol component shown below, excellent workability at the time of producing a polyurethane pre-polymer, and Used for synthetic leather, etc., which has excellent appearance and flexibility, and gives a film with excellent heat resistance, hydrolysis resistance, weather resistance, and low-temperature characteristics. They found that an aqueous polyurethane coating composition was obtained, and completed the present invention.

 That is, the first aspect of the present invention is to use a polyol component (A), an organic polyisocyanate component (B), a diol containing a hydrophilic group (C), a chain extender (D), and if necessary, In the aqueous polyurethane coating composition containing a curing agent (E) and water, at least 40% by weight of the polyol component (A) is a low molecular weight compound having at least two active hydrogen groups as an initiator. The copolymer obtained by ring-opening copolymerization of ε-force prolactone and δ-valerolactone at a molar ratio of ε-force prolactone / <5-valerolactone = 80Ζ20 to 20Ζ80 Provided is an aqueous polyurethane coating composition, which is a polymerized lactone polyol.

The second aspect of the present invention is that the copolymerized lactone polyol has a number average molecular weight of 500 to 500, and the polyol component (Α) has a number average molecular weight of 500 to 400 An aqueous polyester resin coating composition according to Invention 1 is provided. A third aspect of the present invention is that the low-molecular-weight compound having at least two active hydrogen groups is ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexane. The present invention provides the aqueous polyurethane coating composition according to the first aspect, which is at least one selected from diol, glycerin, trimethylolpropane, triethanolamine, and pentaerythritol. A fourth aspect of the present invention is that the diol (C) containing a hydrophilic group is 2,2-dimethylolpropionic acid and / or a salt thereof, 2,2-dimethylthiolbutanoic acid and / or a salt thereof, and a lipoxyl group 4. The aqueous polyurethane coating composition according to any one of the above inventions 1 to 3, which is at least one selected from polyester polyols containing Ζ or 塩 or a salt thereof. A fifth aspect of the present invention is that a polyester polyol containing a carboxylic acid group and a salt thereof is obtained by using 2,2-dimethylmethylpropionic acid and a salt thereof, or 2,2-dimethylolbutanoic acid and a salt thereof as an initiator. Molecular weight of ring-opening addition polymerized ε-force prolactone 40 The present invention provides the aqueous polyurethane coating composition according to the above invention 4, which is a polyproprolactone polyester polyol containing 0 to 300,000 hydroxyl groups and / or a salt thereof. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described.

 As a method for producing the aqueous polyurethane coating composition of the present invention, a method for synthesizing a general aqueous polyurethane resin can be used. Typically, first, a mixture of a polyol component (A), a polyol containing a hydrophilic group (C), and a curing agent (E) used as needed in the presence or absence of an organic solvent. An excess amount of the organic polyisocyanate component (B) is added to the mixture, and the mixture is reacted at a temperature of 50 to 120 ° C. to synthesize a hydrophilic group-containing polyurethane prepolymer having a terminal NC 0. When a diol (C) whose hydrophilic group is, for example, a lipoxyl group is used, a neutralizing agent is added to obtain a polyurethane prevolimer in which part or all of the lipoxyl group is a salt. To this, ion-exchanged water or distilled water is added with vigorous stirring to obtain an aqueous dispersion. In the dispersing step (phase conversion step), a method is preferably used in which the polyurethane prepolymer having a neutralized hydrophilic group is added to ion-exchanged water or distilled water with vigorous stirring. The aqueous polyurethane coating composition of the present invention is obtained by adding a chain extender (D) to the aqueous dispersion to increase the molecular weight of the polyurethane prepolymer.

Generally, an organic solvent is often used during the reaction or after the reaction to prepare an aqueous dispersion in order to control the reaction and reduce the viscosity during the synthesis of the polyurethane prepolymer, and examples of the organic solvent include: Aliphatic hydrocarbons such as n-hexane, n-heptane and cyclohexane; alicyclic hydrocarbons such as tetralin; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone (hereinafter referred to as MEK) Ketones such as methylisobutyl ketone; ethers such as tetrahydrofuran Acetates such as ethyl acetate, butyl acetate, ethyl acetate sorb acetate; ethers such as dioxane and tetrahydrofuran; methanol, ether, and isopropyl alcohol (hereinafter also referred to as IPA) And alcohols such as n-propyl alcohol and butanol; and amides such as dimethylformamide and N-methylpyrrolidone.

 Since the organic solvent is evaporated and removed from the aqueous dispersion of the polyurethane prepolymer at 25 to 60 ° C. under reduced pressure, it is preferable to use a solvent having a relatively low boiling point that is easily evaporated and removed, From the viewpoint of the solubility of the polyurethane prepolymer, ethyl acetate, butyl acetate, acetone, and methyl ethyl ketone are preferably used. The amount of the organic solvent used is from 0 to 100 parts by weight, preferably from 5 to 80 parts by weight, more preferably from 10 to 50 parts by weight, based on 100 parts by weight of the obtained polyurethane prepolymer. It is. If the amount is more than 100 parts by weight, the reaction speed in synthesizing the polyurethane prepolymer decreases, the adverse effect of chain transfer appears, and after the phase inversion, the organic solvent is removed by evaporation of the organic solvent. It is not preferable from the viewpoint of heat history and energy economy in preparing the composition.

 The copolymerized lactone polyol used in the present invention is obtained by ring-opening copolymerization of ε-force prolactone and <5-valerolactone using at least one low molecular weight compound having two or more active hydrogen groups as an initiator. is there. A copolymerized lactone polyol having a number average molecular weight of 500 to 50,000 is preferably used. The copolymerized lactone polyol accounts for at least 40% by weight of the polyol component (Α).

 In order to synthesize the copolymerized lactone polyol used in the present invention, a general method for obtaining a polyol compound by ring-opening polymerization of a cyclic lactone compound can be used. That is, it can be obtained by reacting a mixture of the initiator, ε-caprolactone and δ-valerolactone at 120 ° C. to 250 ° C. for 2 to 50 hours in the presence of a catalyst. .

The initiator used to synthesize the copolymerized lactone polyol used in the present invention Any low-molecular weight compound having at least two active hydrogen groups in one molecule may be used. For example, a polyol compound or a polyamine compound is used. As the polyol compound, various known compounds generally known as a glycol component of a polyester as described below can be used. For example, the molecular weight is 100,000 or less, preferably 500 or less, for example, ethylene dalicol, ethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3 —Butanediol, 1,4-butanediol, neopentyldaricol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-2-propyl-1,3-propanediol, 2,2-ethylethyl Various known glycols such as 1,3-propanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, and 1,4-butenediol Can be Further, in the present invention, in addition to the above-mentioned glycols, alkyldaricidyl ethers such as n-butyldaricidyl ether and 2-ethylhexyldaricidyl ether, and monocarboxylic glycidyl esters such as versatic acid glycidyl ester. Can also be used as a type of glycols. Further, compounds having three or more active hydrogen groups in one molecule include, for example, glycerin, trimethylolpropane, trimethylolethane, 1,2,61-hexanetriol, 1,2,4-butanetriol Sorbitol, pentaerythritol, triethanolamine and the like. Among these polyols, ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane and glycerin are particularly preferable. preferable.

Examples of polyamine compounds include ethylenediamine, p-phenylenediamine, hexamethylenediamine, tetraethylenediamine, isophoronediamine, diaminonodiphenylmethane, hydrogenated diaminodiphenylmethane, and propanediamine. Among them, ethylenediamine, hexamethylenediamine and isophoronediamine are preferred.

 In the present invention, the molar ratio of the cyclic lactone compound used, ε-force prolactone and δ-valerolactone, is in the range of 20/80 to 80/20, preferably 30/70. 0 to 70/30. When the constituent ratio of ε-force prolactone and << one lactone compound among valerola lactones exceeds 80 mol%, the crystallinity of the obtained copolymerized lactone polyol becomes high, and when it is formed into a polyurethane prepolymer, It is necessary to heat and melt the mixture, which is not preferable because of poor handling. Further, when the coating film obtained from the obtained aqueous polyester coating agent composition is exposed to a low temperature, the copolymerized lactone polycarbonate may crystallize and whiten, which is not preferable. In the present invention, in addition to ε-force prolactone and δ-valerolactone, trimethyl-ε-force prolactone, monomethyl-1-ε-force prolactone, avetyrolactone, monomethyl-1- <5-valerolactone and the like can be used. For example, when a cyclic lactone compound other than ε-force prolactone and δ-valerolactone is added, the amount of addition is 20 mol% or less in 100 mol% of the total cyclic lactone compound.

The number average molecular weight of the copolymerized lactone polyol used in the present invention is appropriately determined in consideration of the feeling, mechanical properties, durability, and the like of the obtained polyurethane film, and is usually 500 to 50,000. , Preferably in the range of 1,000 to 4,000. If the number average molecular weight is less than 500, the resulting polyurethane film becomes too hard, loses flexibility, and has a poor feel. On the other hand, if it exceeds 50,000, the viscosity becomes high or becomes waxy when synthesizing the urethane prepolymer, so that a large amount of organic solvent must be used, and the reaction requires a long time. This is not desirable. Further, the obtained polyurethane film becomes too soft, which is not preferable. The copolymerized lactone polyol used in the present invention may be used alone as the polyol component (Α), but may be used within a range not deviating from the intended performance of the present invention. If present, it can be used in combination with other polyols. For example, polyether polyols such as polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran using water or low molecular weight polyols as initiators, and polyester polyols obtained by condensing a dibasic acid and a glycol component , Polylactone polyols obtained by ring-opening polymerization of one kind of cyclic ester compound such as a lactone compound using water or low molecular weight polyol as an initiator, other polypolyester polyols, and polybutane glycol And various known high-molecular polyols generally used in the production of polyurethanes, such as glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A. The copolymerized lactone polyol used in the present invention accounts for at least 40% by weight of the polyol component (A). Preferably, the content is 50% by weight or more, more preferably 60% by weight or more. If the proportion of the copolymerized lactone polyol in (A) is less than 40% by weight, the resulting polyurethane film tends to have a poor balance of properties of feeling, weather resistance, heat resistance and low-temperature properties, which is not preferred. The number average molecular weight of the polyol component (A) is from 500 to 400, preferably from 700 to 300. If it is less than 50,000, the obtained polyurethane film is hard and the texture becomes poor, and if it is more than 4,000, the polyurethane film becomes soft and the strength is reduced. In the present invention, an organic polyisocyanate component (B) is reacted with a mixture of a polyol component (A), a diol containing a hydrophilic group (C), and a curing agent (E) used as required, to thereby provide hydrophilicity. Polyurethane prepolymer containing a hydrophilic group is prepared, and the polyurethane prepolymer containing a hydrophilic group is dispersed in water. Then, a chain extender (D) described below and, if necessary, a chain extender are added. After the reaction, the aqueous polyurethane coating composition of the present invention is obtained. The chain extender (D) and the like may be added before dispersing in water.

As the organic polyisocyanate component (B), various known aromatic, aliphatic or alicyclic polyisocyanates can be used. For example, 1, 5-na 4 'diphenyl dimethyl methane diisocyanate, 4, 4'-dibenzyl isocyanate, di (alkyl-substituted phenyl) methane diisocyanate, di (tetraalkyl-substituted phenyl) methane diisocyanate, 1,3-phenyl 1,2-diphenylisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4,1-trimethylhexamate Tylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate Neat, 4,4,1-dicyclohexylmethane-diisocyanate, 1,3-bis

(Isocyanatomethyl) cyclohexane, methylcyclohexanediisocyanate, m-tetramethylxylylenediisocyanate, dimer diisocyanate in which the carboxyl group of dimeric acid is converted to an isocyanate group, etc. This is a typical example. Of these, isophorone diisocyanate, hexamethylene diisocyanate, 4,4, -diphenylmethane diisocyanate, and tolylene diisocyanate are preferred.

The chain extender (D) used in the present invention includes, for example, ethylenediamine, prontriamine, isophoronediamine, dicyclohexylmethane-1,4, -diamine and the like. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, Representative examples thereof include diamines having a hydroxyl group in the molecule such as di-2-hydroxypropylethylenediamine, and diamine diamine in which the lipoxyl group of the low-molecular-weight glycol-dimer acid described in the above-mentioned polyester diol is converted to an amino group. As an example. The chain extender (D) used in the present invention may be any compound having at least two active hydrogens capable of reacting with the isocyanate. For example, diols, triols and amine compounds mentioned in the curing agent (E) may be used. In general, a diamine compound having a high reactivity with an isocyanate is preferably used since it is added after the polyurethane prepolymer is dispersed in water, and ethylenediamine, isophoronediamine, and diaminodicyclohexylmethane are generally used. Particularly preferably used. Further, a chain elongation terminator or a terminal blocking agent may be used as necessary. Examples of such a chain extension terminator include dialkylamines such as di-n-butylamine, alcohols such as ethanol and isopropyl alcohol, and amino alcohols such as monoethanolamine.

The method for producing the polyurethane prepolymer, which is the first step for producing the aqueous polyurethane resin coating composition of the present invention, is not particularly limited, and the components (A) to (E) are reacted at once. It may be manufactured by any of the (i) one-shot method and (ii) the multi-stage method. The multi-stage method is a method in which the reaction is carried out stepwise. For example, a polyol component (A) and an organic polyisocyanate component (B) are reacted under an excess of isocyanate group, and the polyol component (A) molecule A polyurethane having an isocyanate group at each end is synthesized, and a curing agent (E) is reacted with the polyurethane to prepare a polyurethane prepolymer, which is then dissolved in an appropriate solvent and dispersed in water. By reacting with the chain extender (D) and, if necessary, the chain extender, the aqueous polyurethane resin film agent composition of the present invention can be obtained. The chain extender (D) may be added before dispersing. The reaction is carried out at a temperature of usually 20 to 140 ° C, preferably 40 to 120 ° C. However, when the amine compound is reacted as the chain extender (D), the reaction is usually performed at a temperature of 100 or less, preferably 0 to 80 ° C. In order to accelerate the reaction, if necessary, a catalyst used in a general polyurethane-forming reaction, for example, an amine catalyst such as triethylamine, N_ethylmorpholine, and triethylenediamine, dibutyltin dilaurate, and octyltin dizilla Tin-based catalysts such as perylate and tin octoate, and titanium-based catalysts such as tetrabutyl titanate may be used.

 The diol (C) containing a hydrophilic group used in the aqueous polyurethane resin film agent composition of the present invention has a hydrophilic group in addition to two hydroxyl groups. For example, dioloxyl group, sulfone group Or a group containing at least two active hydrogen atoms in the molecule, and a group consisting of repeating units of ethylene oxide; repeating units of ethylene oxide and other alkylene oxides Nonionic compounds containing a group consisting of units are exemplified.

 Examples of the carboxyl-containing diol (C) include 2,2-dimethylolpropionic acid (DMPA), 2,2-dimethylolbutanoic acid (DMBA), 2,2-dimethylolbutyric acid, and 2,2-dimethylol Cyclic ester-containing compounds such as valeric acid, dioxymaleic acid, 2,6-dioxybenzoic acid, 3,4-diaminobenzoic acid, and derivatives and salts thereof, or ring-opening addition of cyclic ester compounds using these as initiators Examples of the resulting polyester polyol having a lipoxyl group include cyclic ester compounds capable of ring opening addition, such as one-pot prolactone, β-pot prolactone, r-pot prolactone, δ-pot prolactone, ε one-pot prolactone. Lactones such as acetone, α-methyl-ε-force prolactone, j3-methyl-ε-force prolactone, and 4-methylcaprolactone Emission class, and the like. Among them, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and ε-force have been considered from the viewpoint of easiness of handling, price, and adhesion of the obtained polyurethane resin composition to leather. Compounds obtained by ring-opening addition polymerization of prolactone are particularly preferred. The number of moles of lactone added is 3 to 45.

Examples of the sulfone group-containing compound include, for example, 2-oxyethanesulfonic acid, phenolsulfonic acid, sulfobenzoic acid, sulfosuccinic acid, 5-sulfoisophthalic acid, sulfanilic acid, 1,3-phenylenediamine-4,6- Various sulfone-containing compounds such as disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid, etc. Polyester polyols, polyamide polyols and polyamide polyester polyols obtained by dehydration condensation with riol are mentioned.

 By neutralizing these hydroxyl groups or sulfone groups into salts, the polyurethane resin finally obtained can be made water-dispersible. Examples of the neutralizing agent include nonvolatile bases such as sodium hydroxide and potassium hydroxide; tertiary amines such as trimethylamine, triethylamine, dimethylethanolamine, methyljetanolamine, and trietanolamine; and ammonia. And the like. The neutralization operation can be performed before, during, or after the urethanization reaction. The degree of neutralization is from 30 to 120 equivalents, preferably from 40 to 110 equivalents, to 100 equivalents of the acid group.

 Further, the nonionic group-containing compound includes an alkylene oxide, preferably an ethylenoxide repeating unit of at least 3 Q% by weight, and a molecular weight of at least one active hydrogen in the molecule of at least 300. And a polyoxyethylene glycol such as polyethylene glycol or polyoxyethylene-polypropylene propylene copolymer glycol, polyoxyethylene-polyoxybutylene copolymer glycol. Nonionic group-containing compounds such as polyoxyalkylene copolymer glycols or monoalkyl ethers thereof, or addition polymerization of ε-force prolactone, δ-valerolactone, aptyrolactone, etc. using these as initiators. And the resulting polyester polyether polyols. Further, polyester polyether polyols obtained by polycondensation of these nonionic group-containing diols and dibasic acids are also included.

 In order to introduce a hydrophilic group into the polyurethane prepolymer, the above compounds may be used alone or in combination.

In the aqueous polyurethane resin film agent composition of the present invention, the content of the hydrophilic group bonded to the molecule is finally obtained when the hydrophilic group is an ionic group such as a sulfoxyl group or a sulfone group. Polyurethane in aqueous polyurethane resin coating composition to be used 1 Preferably 0.05 to 0.2 equivalents, more preferably 0.01 to 0.1 equivalents per 0.0 parts by weight are required.

 When a nonionic group-containing compound is used, the compound is used in an amount of 1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the polyurethane in the finally obtained aqueous polyurethane resin coating composition. It is preferable to use one of the parts.

 In addition, in the aqueous polyurethane coating composition of the present invention, when the polyurethane prepolymer containing a hydrophilic group is dispersed in water, an external emulsifier is used in addition to using the hydrophilic group-containing compound as a raw material component. It does not matter. Examples of such external emulsifiers include nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrenated phenyl ether, and polyoxyethylene sorbitol tetraoleate; sodium oleate; Anionic emulsifiers such as fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, alkane sulfonate sodium salts, alkyl diphenyl ether sulfonate sodium salts, etc .; Nonionic anionic emulsifiers such as alkyl sulfates and polyoxyethylene alkylphenyl sulphates; cationic emulsifiers such as alkyltrimethyl ammonium salts; and fluorine-based and silicon-based emulsifiers Special emulsifying agent of the emissions system, and the like. The amount of the emulsifier used is preferably from 0.1 to 20 parts by weight, more preferably from 1 to 5 parts by weight, based on 100 parts by weight of the polyurethane.

The curing agent (E) optionally used in the present invention may be any compound having at least two active hydrogens capable of reacting with isocyanate. Examples thereof include ethylene glycol, propylene glycol, and 3-methyl-1. , 3-propanediol, 1,3-butanediol, 1,4-butanediol, dimethylpropanediol, 2,2-getyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2 —Ethyl-1,3-hexanediol, 1,6-hexane Short-chain diols such as diol, 1,5-pentanediol, 3-methyl-115-pentanediol, octanediol, neopentyl glycol, 1,4-cyclohexyldimethyl alcohol, diethylene glycol, dipropylene glycol, etc. Furthermore, triols such as glycerin and trimethylolpropane, ethylendiamine, propylenediamine, hexamethylenediamine, hydrazine and hydrazine derivative compounds, piperazine and piperazine compounds, diaminodiamine Examples include amine compounds such as cyclohexylmethane, diphenylmethanediamine, xylenediamine, and isophoronediamine. One or more of these are used in combination, and particularly, ethylene glycol, 3-methyl-1,3-propanediol, and 1,4-butanediol are particularly preferably used.

 The amount of the curing agent (Ε) to be used is preferably 6 times or less the total number of moles of the polyol component (成分), and is preferably 4 times or less. Particularly preferred. The amount 0 of the curing agent (Ε) used is also within the range of the present invention, but in that case, the obtained aqueous polyurethane coating composition of the present invention has a reduced cohesive strength and cannot obtain sufficient strength, which is relatively undesirable. If the amount is more than 6 times, it becomes too hard to reduce the feeling, and further, the viscosity of the resin solution increases during the synthesis of the hydrophilic group-containing polyurethane prepolymer, which is not preferable because the handling becomes difficult.

 A neutralizing agent is added, and ion-exchanged water or distilled water is added to the resulting polyurethane polymer obtained by converting a part or all of the hydrophilic groups into a salt while stirring vigorously to obtain an aqueous dispersion. The aqueous polyurethane coating composition of the present invention is obtained by adding a chain extender (D) to the aqueous dispersion obtained in the dispersing step (phase inversion step) to reduce the molecular weight of the polyurethane polyurethane prepolymer to a lower molecular weight. The amount of water used is 50 to 400 parts by weight, preferably 100 to 300 parts by weight, based on 100 parts by weight of the polyurethane prepolymer. The chain extender (D) may be added before the dispersing step (phase change step).

The chain extender (D) is a hydrophilic group-containing polyurethane prepolymer before being dispersed in water. The required amount may be added directly to the above solution, but in general, after a hydrophilic group-containing polyurethane prepolymer is made into an aqueous dispersion, a 10 to 20% by weight aqueous solution or a solvent solution is used. Is added. The amount of the chain extender (D) added is the total active hydrogen of the polyol component (A), the diol containing a hydrophilic group (C), the curing agent (E) and the chain extender (D) based on the total NCO equivalent. The ratio of the base equivalents is adjusted so as to be 0.9 to 1.5, preferably 1.0 to 1.2.

 The solid content in the aqueous polyurethane coating composition of the present invention is preferably 30 to 65% by weight, particularly preferably 35 to 60% by weight. If the solid content is less than 30% by weight, drying takes a long time and the efficiency is lowered, which is not preferable. If the content exceeds 65% by weight, the viscosity becomes too high, and workability and coating properties are deteriorated. Absent. Although the aqueous polyurethane coating composition of the present invention provides a coating having excellent mechanical properties and heat resistance without using a crosslinking agent, the coating has a higher level of durability, for example, heat resistance and solvent resistance. A cross-linking agent can be used for imparting properties, water resistance, moist heat resistance, weather resistance, and the like. Examples of the crosslinking agent include an epoxy resin, a melamine resin, an isocyanate compound, an aziridine compound, a polycarboimide compound, and a polyoxazoline compound.

(Example)

 Hereinafter, the present invention will be described in detail with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to these Examples and the like.

Production example 1>

In a round-bottomed flask equipped with a stirrer, thermometer, water separator and nitrogen gas inlet tube, 595 parts by weight of ε-caprolactone and 347 parts by weight of δ-valerolactone, and 1,6- Hexanediol (59 parts by weight) was charged, and polymerization was carried out at 180 under a nitrogen stream for 6 hours. After confirming that the total content of the remaining ε-force prolactone and (5-valerolactone) was 2% by weight or less, gradually use a vacuum pump. The vacuum was increased to remove ε-force prolactone and δ-valerolactone. Thus, hydroxyl value 56.4 KOHmg / g, acid value 0.06 KOHmgZg, moisture content 0.005%, viscosity at 25 ° C 250 OmPas, number average molecular weight 2,000, ε-force prolactone — A copolymerized lactone polyol (a1) having a valerolactone molar ratio of 60/40 was obtained.

<Production Example 2>

 ε-strength prolactone Ζ (5-valerolactone) was prepared in the same manner as in Production Example 1 except that 704 parts by weight of ε-strength prolactone, 265 parts by weight of <5-valerolactone, and 31 parts by weight of ethylene glycol as an initiator were used. Thus, a copolymerized lactone polyol (a 2) having a molar ratio of 70/30 was obtained, having a hydroxyl value of 56.4 KOHmg / g, an acid value of 0.08 K〇Hmg / g, and a moisture content of 0.005%. , 25, the viscosity was 2800 mPa · s, and the number average molecular weight was 2,000.

Manufacturing example 3>

 The same method as in Production Example 1 was used except that 209 parts by weight of ε-force prolactone, 732 parts by weight of δ-valerolactone, and 59 parts by weight of 1,6-hexanediol as an initiator were used. A copolymer lactone polyol (a3) having a molar ratio of 5-valerolactone of 20/80 was obtained. This polyol had a hydroxyl value of 56.5 KO Hmg / g> an acid value of 0.07 K〇Hmg / g, a water content of 0.006%, a viscosity at 25 ° C of 270 OmPa · s, and a number average molecular weight of 2,000.

<Production Example 4>

ε- force caprolactone 553 parts by weight and d one valerolactone 323 parts by weight, and the initiator as ethylene glycol 124 parts by weight and, except the Production Example 1 and the same way in ε Ichiriki caprolactone / ^/ <5- Valero A copolymerized lactone polyol (a4) having a lactone molar ratio of 60/40 was obtained. This polyol had a hydroxyl value of 224.7 KOH mgZg, an acid value of 0.09 KOH mgZg, a water content of 0.006%, a viscosity at 25 ° C of 70 OmPa · s, and a number average molecular weight of 500. <Production Example 5>

 ε-force prolactone / δ in the same manner as in Production Example 1 except that 607 parts by weight of ε-force prolactone, 354 parts by weight of δ-valerolactone, and 39 parts by weight of 1,6-hexanediol as an initiator were used. A lactone polyol (a5) having a valerolactone molar ratio of 60/40 was obtained. This polyol had a hydroxyl value of 37.3 KO HmgZg, an acid value of 0.0 SKOHmgZg, a water content of 0.005%, a viscosity at 25 ° C of 4, 90 OmPa · s, and a number average molecular weight of 3,000.

<Production Example 6>

 ε-force prolactone / δ in the same manner as in Production Example 1 except that 106 parts by weight of ε-force prolactone, 835 parts by weight of δ-valerolactone, and 59 parts by weight of 1,6-hexanediol as an initiator were used. A lactone polyol (a6) having a valerolactone molar ratio of 10/90 was obtained. This polyol had a hydroxyl value of 56.3 KO Hmg / g, an acid value of 0.05 KOHmgZg, a water content of 0.005%, and a number average molecular weight of 2,000.

 The polyol had a high crystallinity and was waxy at room temperature.

Manufacturing example 7>

 ε-force prolactone / δ-valerolactone in the same manner as in Production Example 1 except that 839 parts by weight of ε-force prolactone, 130 parts by weight of δ-valerolactone, and 31 parts by weight of ethylene glycol as an initiator were used. A copolymerized lactone polyol (a7) having a molar ratio of 85/15 was obtained. This polyol had a hydroxyl value of 56.4 KOHmg Zg, an acid value of 0.08 KOHmg / g, a water content of 0.006%, a viscosity at 25 ° C of 2500 mPa-s, and a number average molecular weight of 2000.

Manufacturing example 8>

ε-force prolactone / δ-valerolactone in the same manner as in Production Example 1 except that 625 parts by weight of ε-force prolactone, 365 parts by weight of δ-valerolactone, and 10 parts by weight of ethylene glycol as an initiator were used. Copolymerization ratio of 60/40 Thus, ton polyol (a8) was obtained. This polyol had a hydroxyl value of 18.8 KOHmg Zg, an acid value of 0.09 KOHmgZg, a water content of 0.007%, a viscosity of 5,300 mPa · s, and a number average molecular weight of 6,000.

<Production Example 9>

 ε-force prolactone-mol of valerolactone in the same manner as in Production Example 1 except that 519 parts by weight of ε-force prolactone, 303 parts by weight of <5-valerolactone, and 177 parts by weight of ethylene glycol as an initiator were used. A copolymerized lactone polyol (a9) having a ratio of 60/40 was obtained. This polyol had a hydroxyl value of 320.8 KOH mg / g, an acid value of 0.06 KOH mgZg, a water content of 0.005%, and a 25T: viscosity of 50 OmPa · s> number average molecular weight of 350.

 [Example 1]

 <Synthesis of a solution of a hydrophilic group-containing polyurethane prepolymer>

 229 g of the copolymerized lactone polyol (al) obtained in Production Example 1 was melted at 60 ° C in a 500 ml separable flask equipped with a thermometer, a nitrogen sealed tube, a stirrer, and a reflux device. 2,2-Dimethylol 72 g of ε-force prolactone adduct of butanoic acid [Placcel 205 205, molecular weight 500, acid value 11.3 KOHmg / g, manufactured by Daicel Chemical Industries, Ltd.], 72 g of curing agent (E) (4) Add 1-butanediol 4 and stir and mix while heating. When the temperature reaches about 60 ° C, add 95 g of isophorone diisocyanate (IPDI), maintain the temperature at 80 to 90 ° C, and proceed with the urethanization reaction for about 2 hours. 100 g of methyl ethyl ketone was added, and the mixture was stirred at 80 ° C. for 30 minutes to obtain a uniform hydrophilic group-containing polyurethane prepolymer solution. The solution had an NCO content of 2.15% by weight, a viscosity of 50 and 470 OmPa · s, with a solids content of 80%.

<Preparation of aqueous polyurethane coating agent composition>

500 g of the solution of the hydrophilic group-containing polyurethane prepolymer obtained above was cooled with stirring at 150 rpm. At the time below, 8 g of triethylamine was added as a neutralizing agent, and after a neutralization reaction for about 30 minutes, the stirring speed was increased to 250 rpm, and 710 g of distilled water was added for about 3 minutes. The mixture was added dropwise over 0 minutes, and the mixture was further stirred for 30 minutes to allow sufficient phase change. Thereafter, 60 g of a 10% by weight aqueous solution of ethylenediamine as a chain extender was added, and the mixture was further stirred for 1 to 3 hours. The mixture was further heated at 40 to 50 ° C under reduced pressure for about 5 hours, and By removing the ketone by evaporation, an aqueous polyurethane coating composition was obtained. This had a viscosity measured at 25 ° C. of 15 mPa · s, pH 7.6, an average particle diameter of 167 zm, and a solid content of 36% by weight at 25 ° C. Table 3 shows these properties. Production of synthetic leather>

 A polyurethane two-component curing adhesive is applied on the release paper with a knife coat so that the thickness after drying becomes 40 im, and a cotton swed-like brushed cloth is laminated as a base material. After drying with hot air at 100 ° C. for 5 minutes and aging at 70 ° C. for 48 hours, the release paper was peeled off to obtain a synthetic leather. The resulting synthetic leather is excellent in hydrolysis resistance, weather resistance, texture and appearance. Table 4 shows these characteristics.

 [Examples 2 to 6]

 A hydrophilic group-containing polyurethane prepolymer solution, an aqueous polyurethane coating composition and a synthetic leather were prepared in the same manner as in Example 1 except that each component having the composition shown in Table 1 was used. Similar film property evaluation tests were conducted for weather resistance, texture, and appearance. Table 3 shows the properties of the aqueous polyurethane coating composition, and Table 4 shows the results of the coating property evaluation test.

 [Comparative Examples 1 to 5]

A solution of a hydrophilic group-containing polyurethane prepolymer, an aqueous polyurethane coating composition and synthetic leather were prepared in the same manner as in Example 1 except that the compositions shown in Table 2 were used, and hydrolysis resistance, weather resistance, and texture were prepared. A similar test was conducted for the appearance. Table 3 shows the properties of the water-based polyester film coating composition, and Table 4 shows the results of the film property evaluation test. "Coating property"

 The sample was placed on a 50-m-thick PET (polyethylene terephthalate) film, applied once with a No. 60 bar coater, and observed for uneven coating. The evaluation was performed by the following method.

 〇: No coating residue is observed.

 X: Residual coating is observed.

 `` Weather resistance test ''

Test pieces of synthetic leather obtained in Examples and Comparative Examples were tested with a Sega Tester Co., Ltd. (QUV) at a test temperature of 50 to 70 ° C, ultraviolet irradiation energy 26 WZ m ² , irradiation 8 hours / wet After a 300-hour test with a 4-hour cycle, a surface wear test was performed using the same equipment and conditions as above, and the state of the sample surface was observed.

 "Texture"

 The synthetic leathers obtained in Examples and Comparative Examples were rubbed by hand and judged by feeling. "Appearance"

 By observing the surface condition, the transparency and the presence or absence of cracks were confirmed. When there is no problem, the evaluation is indicated by 〇, and when there is a problem, the state is specifically described.

 "Low temperature characteristics"

 The synthetic leathers obtained in the examples and comparative examples were put into a thermostat at 110, allowed to stand for 5 hours, taken out, and the state of the sample surface was observed.

 〇: Whitening is observed

 X: Maintains transparency without whitening

 The hydroxyl value and the acid value were measured by the method specified in 6.4 of JISK-1557, and the water content was measured by the Karl Fischer method. The viscosity is measured using a Ε-type viscometer, and the number average molecular weight is a value obtained from the obtained hydroxyl value and acid value by the following formula.

Number average molecular weight = (56.11 1 ΧΝΧ 1000) / hydroxyl value N is the number of active hydrogen groups of the low molecular weight compound having at least two active hydrogen groups as an initiator.

The average particle diameter was measured by a light scattering method. The NCO content was measured by the n-butylamine back titration method.

Table 1 Raw material ratio of prepolymer and coating agent composition

Note 1) and Note 2) are described below. Table 2

Note 1) and Note 2) are described below. Table 3 Aqueous polyurethane coating composition

 Solid content Viscosity Average particle size P H Number average molecular weight (% by weight) (25, mPa-s) (in)

Example 1 36 15 167 7.6 45000 Example 2 36 38 98 7.4 48000 Example 3 34 18 173 7.5 5.1000 Example 4 34 53 85 7.3 38000 Example 5 36 31 100 7.5 55000 Example 6 36 45 91 7.5 40000 Comparative Example 1 34 19 152 7.4 42000 Comparative Example 2 35 28 112 7.3 39 000 Comparative Example 3 35 365 223 7.4 68000 Comparative Example 4 36 238 210 7.8 34000 Comparative Example 5 35 16 178 7. 6 43000

Table 4 Synthetic leather evaluation results

Abbreviations and notes in the above table are as follows.

PTMG 2000: Polytetramethylene glycol with a number average molecular weight of 2000, manufactured by Mitsubishi Chemical Corporation, paste form (25 ° C)

 205 B A: Plaxel 205 B A [ε-one-prolactone adduct of dimethylolbutanoic acid having a number average molecular weight of 500 and an acid value of 11.3 KOHmgZg, manufactured by Daicel Chemical Industries, Ltd.]

 2 10 A: Daicel Chemical Industries, Ltd., ε-force prolactone adduct to dimethylol propionic acid with a number average molecular weight of 1000, waxy (25 ° C)

 DMPA: dimethylolpropionic acid

 1,4-BD: 1,4_butanediol

TEA: Triethylamine EDA: ethylenediamine

 CLM: ε-force prolactone

 VLM: δ-valerolactone

 ΜΕΚ: Methyl ethyl ketone

 Note 1): Molecular weight of copolymerized lactone polyols (a l) to (a 9) used as polyol component (ポ リ オ ー ル)

 Note 2): Ratio of copolymerized lactone polyol (a l) to (a 9) in the polyol component (A) Industrial applicability

 The aqueous polyurethane coating composition of the present invention provides a synthetic leather having excellent heat resistance, hydrolysis resistance, abrasion resistance, flexibility, and weather resistance, particularly, a sheet material for an automobile, a sheet material for furniture, a tongue, and miscellaneous goods. It can form a surface film layer of leather used for clothing, clothes, and shoes.

Claims

The scope of the claims

 1. A polyol component (A), an organic polyisocyanate component (B), a diol containing a hydrophilic group (C), a chain extender (D), and a curing agent (E) used as needed. In an aqueous polyurethane coating composition containing water, at least 40% by weight of the polyol component (A) is obtained by using a low molecular weight compound having at least two active hydrogen groups as an initiator and ε-force prolactone. And <5-valerolactone in a molar ratio of ε-force prolactone / <5_valerolactone = 80/20 to 20/80. Aqueous polyurethane coating composition.

 2. The aqueous polyurethane coating composition according to claim 1, wherein the number average molecular weight of the copolymerized lactone polyol is from 500 to 5,000, and the number average molecular weight of the polyol component (量) is from 500 to 4,000.

 3. The low molecular weight compound having at least two active hydrogen groups is ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, neopentyldaricol, 1,6-hexanediol, glycerol. 2. The aqueous polyester resin coating composition according to claim 1, which is at least one member selected from the group consisting of trimethylolpropane, trimethylolamine and penylerythritol.

 4. The diol (C) containing a hydrophilic group has 2,2-dimethylolpropionic acid and Ζ or a salt thereof, 2,2-dimethylthiolbutanoic acid and Ζ or a salt thereof, and a lipoxyl group The aqueous polyurethane coating composition according to any one of claims 1 to 3, wherein the composition is at least one selected from a polyester polyol and / or a salt thereof.

5. When the polyester polyol having a hydroxyl group or a salt thereof is 2,2-dimethylolpropionic acid and a salt thereof, or 2,2-dimethylol A polyfunctional prolactone polyester polyol or a salt thereof having a molecular weight of from 400 to 300, having a molecular weight of 400 to 300, obtained by ring-opening addition polymerization of ε-force prolactone using butanoic acid and Z or a salt thereof. Item 6. The aqueous polyurethane coating composition according to Item 4.