Aqueous urethane resin composition, coating film, and article

Abstract

The present invention is an aqueous urethane resin composition that comprises a urethane resin (A), an aqueous medium (B), and a crosslinking agent (C), and that is characterized in that: essential raw materials for the urethane resin (A) are a polyisocyanate compound (a2) and a polyol compound (a1) including a polyoxyethylene glycol (a1-1) and / or a polyoxyethylene polyoxypropylene glycol (a1-2); and the crosslinking agent (C) includes an epoxy-based crosslinking agent having a polyoxyethylene chain. The aqueous urethane resin composition can form a coating film having excellent moisture permeability and water resistance.

Description

Water-based urethane resin composition, film and article

[0001] The present invention relates to an aqueous urethane resin composition, a coating, and an article.

[0002] Urethane resin compositions generally have good adhesion to substrates and are capable of forming flexible coating films, and are therefore used in a variety of applications including coating agents and adhesives.

[0003] In particular, due to its mechanical strength and good texture, it is widely used in the production of synthetic leather (including artificial leather), and solvent-based urethane resins containing N,N-dimethylformamide (DMF) have been the mainstream for this application until now. However, against the backdrop of DMF restrictions in Europe, stricter VOC emission restrictions in China and Taiwan, and DMF restrictions imposed by major apparel manufacturers, there is a demand for DMF-free urethane resins that make up synthetic leather.

[0004] In order to respond to such changes in the times, urethane resin compositions in which urethane resins are dispersed in water, etc., have been widely studied (see, for example, Patent Document 1). However, although studies on replacement have been conducted, it has often been pointed out that these compositions are inferior to solvent-based compositions in terms of physical properties.

[0005] Furthermore, in the fields of sports shoes, functional shoes, breathable clothing, and the like, there is a trend toward eliminating DMF, but water-based materials have insufficient breathability and water resistance, and do not satisfy the increasingly high performance requirements of recent years.

[0006] The water-based urethane resins used in these products are required to have durability equivalent to that of solvent-based urethane resins, but because the resin itself contains a hydrophilic component or an emulsifier component, the durability of the resin alone tends to be low. Furthermore, the film-forming properties, heat discoloration resistance, flexibility, heat resistance, and moist heat resistance are insufficient, and the performance requirements that have been increasing recently have not been met.

[0007] Therefore, there is a need for materials with even better moisture permeability and water resistance.

[0008] Japanese Patent Application Laid-Open No. 2007-119749

[0009] The problem to be solved by the present invention is to provide an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance, a film formed from the aqueous urethane resin composition, and an article having the film.

[0010] As a result of intensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using an aqueous urethane resin composition containing a urethane resin made from specific raw materials, an aqueous medium, and a specific crosslinking agent, and have thus completed the present invention.

[0011] Specifically, the present invention relates to an aqueous urethane resin composition comprising a urethane resin (A), an aqueous medium (B), and a crosslinking agent (C), wherein the urethane resin (A) comprises, as essential raw materials, a polyol compound (a1) containing polyoxyethylene glycol (a1-1) and / or polyoxyethylene polyoxypropylene glycol (a1-2), and a polyisocyanate compound (a2), and the crosslinking agent (C) contains an epoxy-based crosslinking agent having a polyoxyethylene chain; a coating formed from the aqueous urethane resin composition; and an article having the coating.

[0012] The present invention provides the following embodiments. [1] An aqueous urethane resin composition comprising a urethane resin (A), an aqueous medium (B), and a crosslinking agent (C), wherein the urethane resin (A) comprises, as essential raw materials, a polyol compound (a1) containing polyoxyethylene glycol (a1-1) and / or polyoxyethylene polyoxypropylene glycol (a1-2), and a polyisocyanate compound (a2), and the crosslinking agent (C) contains an epoxy-based crosslinking agent having a polyoxyethylene chain. [2] The aqueous urethane resin composition according to [1] above, wherein the ethylene oxide concentration in the urethane resin (A) is in the range of 1 to 6 mmol / g. [3] The aqueous urethane resin composition according to [1] or [2] above, wherein the polyol compound (a1) further contains a polyether polyol other than the polyoxyethylene glycol (a1-1) and the polyoxyethylene polyoxypropylene glycol (a1-2). [4] The aqueous urethane resin composition according to any one of [1] to [3], wherein the amount of the crosslinking agent (C) used is 0.5 parts by mass or more per 100 parts by mass of the total of the urethane resin (A) and the aqueous medium (B). [5] The aqueous urethane resin composition according to any one of [1] to [4], wherein the epoxy-based crosslinking agent having a polyoxyethylene chain is polyethylene glycol diglycidyl ether. [6] The aqueous urethane resin composition according to [5], wherein the polyethylene glycol diglycidyl ether has a number-average molecular weight in the range of 100 to 1500. [7] A film formed from the aqueous urethane resin composition according to any one of [1] to [6]. [8] An article having the film according to [7].

[0013] The aqueous urethane resin composition of the present invention has excellent moisture permeability and water resistance, and can therefore be suitably used for synthetic leather, moisture-permeable clothing, and moisture-permeable films.

[0014] The aqueous urethane resin composition of the present invention is characterized by comprising a urethane resin (A), an aqueous medium (B), and a crosslinking agent (C).

[0015] The urethane resin (A) used contains a polyol compound (a1) and a polyisocyanate compound (a2) as essential raw materials.

[0016] As the polyol compound (a1), polyoxyethylene glycol (a1-1) and / or polyoxyethylene polyoxypropylene glycol (a1-2) are used as essential components.

[0017] The polyoxyethylene glycol (a1-1) can be, for example, a product obtained by ring-opening polymerization of ethylene oxide alone or ethylene oxide and propylene oxide in combination with a low-molecular-weight polyol as an initiator.

[0018] Examples of the low molecular weight polyol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol.

[0019] The number average molecular weight of the polyoxyethylene glycol (a1-1) is preferably in the range of 1,000 to 25,000, and more preferably in the range of 2,000 to 5,500, since an aqueous urethane resin composition having excellent chemical resistance and low-temperature flexibility can be obtained.

[0020] Examples of the polyoxyethylene polyoxypropylene glycol (a1-2) that can be used include random copolymers in which a mixture of ethylene oxide (hereinafter sometimes referred to as "EO") and propylene oxide (hereinafter sometimes referred to as "PO") is added to ethylene glycol or propylene glycol as an initiator; copolymers in which propylene oxide is added to ethylene glycol or propylene glycol as an initiator, and then ethylene oxide is added to the terminal; and block copolymers in which ethylene oxide is added to ethylene glycol or propylene glycol as an initiator, and then propylene oxide is added to the terminal. These polyoxyethylene polyoxypropylene glycols can be used alone or in combination of two or more.

[0021] The ratio of the number of moles of EO added to the number of moles of PO added in the polyoxyethylene polyoxypropylene glycol (a1-2) [EO / PO] is preferably in the range of 10 / 90 to 99 / 1, since an aqueous urethane resin composition having excellent chemical resistance and low-temperature flexibility can be obtained.

[0022] The number average molecular weight of the polyoxyethylene polyoxypropylene glycol (a1-2) is preferably in the range of 500 to 3,000, more preferably in the range of 1,000 to 2,000, since an aqueous urethane resin composition having excellent chemical resistance and low-temperature flexibility can be obtained.

[0023] As the polyol compound (a1), polyol compounds other than the polyoxyethylene glycol (a1-1) and the polyoxyethylene polyoxypropylene glycol (a1-2) (hereinafter abbreviated as "other polyol compounds") can also be used, if necessary.

[0024] Examples of the other polyol compounds include polyester polyols, polyether polyols other than the polyoxyethylene glycol (a1-1) and the polyoxyethylene polyoxypropylene glycol (a1-2), polycarbonate polyols, polybutadiene polyols, etc. These polyol compounds can be used alone or in combination of two or more.

[0025] Examples of the polyester polyol include those obtained by esterifying a polycarboxylic acid with a polyhydric alcohol.

[0026] Examples of the polycarboxylic acid include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid, and esters thereof, and aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, maleic acid, pimelic acid, suberic acid, azelaic acid, itaconic acid, sebacic acid, chlorendic acid, 1,2,4-butanetricarboxylic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, dimer acid, and fumaric acid, and esters thereof. These polycarboxylic acids and esters thereof can be used alone or in combination of two or more.

[0027] Examples of the polyhydric alcohol include aromatic diols such as benzenedimethanol, toluenedimethanol, and xylene dimethanol, and aliphatic polyols such as ethylene glycol, propylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, and neopentyl glycol ethylene glycol. These polyhydric alcohols can be used alone or in combination of two or more.

[0028] In the esterification reaction for producing the polyester polyol, it is preferable to use an esterification catalyst for the purpose of accelerating the esterification reaction. Examples of the esterification catalyst include metals such as titanium, tin, zinc, aluminum, zirconium, magnesium, hafnium, and germanium; and metal compounds such as titanium tetraisopropoxide, titanium tetrabutoxide, titanium oxyacetylacetonate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, tin octoate, 2-ethylhexanetin, zinc acetylacetonate, zirconium tetrachloride, zirconium tetrachloride tetrahydrofuran complex, hafnium tetrachloride, hafnium tetrachloride tetrahydrofuran complex, germanium oxide, and tetraethoxygermanium. These esterification catalysts can be used alone or in combination of two or more.

[0029] Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene polyoxytetramethylene glycol, etc. These polyether polyols can be used alone or in combination of two or more.

[0030] Examples of the polycarbonate polyol include polycarbonate polyols obtained by reacting a carbonate ester and / or phosgene with a diol compound.

[0031] Examples of the carbonate ester include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, etc. These carbonate esters can be used alone or in combination of two or more.

[0032] Examples of the diol compound include aliphatic diol compounds such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,5-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,8-nonanediol, 1,10-decanediol, 2-ethyl-2-butyl-1,3-propanediol, and 1,12-dodecanediol; and alicyclic diol compounds such as 1,4-cyclohexanedimethanol and 1,3-cyclohexanedimethanol. These diol compounds can be used alone or in combination of two or more.

[0033] The number average molecular weight of the other polyol compounds is preferably in the range of 200 to 100,000, more preferably in the range of 500 to 10,000, since an aqueous urethane resin composition having excellent chemical resistance and low-temperature flexibility can be obtained. In the present invention, the number average molecular weight of the polyol compounds indicates a value measured by gel permeation chromatography (GPC).

[0034] The amount of the other polyol compounds used is preferably in the range of 0 to 90% by mass, more preferably 0 to 40% by mass, in the polyol compound (a1).

[0035] Examples of the polyisocyanate compound (a2) include aromatic polyisocyanates such as phenylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate; aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate; and alicyclic diisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, di(isocyanatemethyl)cyclohexane, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and norbornane diisocyanate. These polyisocyanates can be used alone or in combination of two or more. Among these, aliphatic polyisocyanates are preferred because they provide an aqueous urethane resin composition having excellent chemical resistance and low-temperature flexibility, and hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate are more preferred.

[0036] The amount of the polyisocyanate compound (a2) used is preferably in the range of 10 to 40 mass %, more preferably in the range of 12 to 37 mass %, and even more preferably in the range of 15 to 35 mass %, of the total mass of the raw materials for the urethane resin (A), since an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance can be obtained.

[0037] In addition to the polyol compound (a1) and the polyisocyanate compound (a2), a compound (a3) ​​having a hydrophilic group can also be used as a raw material for the urethane resin (A), if necessary.

[0038] Examples of the compound (a3) ​​having a hydrophilic group include a compound having a carboxyl group as the hydrophilic group, a compound having a sulfonic acid group as the hydrophilic group, and a compound having a polyalkylene oxide structure as the hydrophilic group.

[0039] Examples of the compound having a carboxyl group as the hydrophilic group include compounds having a carboxyl group such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2′-dimethylolvaleric acid, and polyol compounds obtained by esterifying the compounds having a carboxyl group.

[0040] Examples of the compound having a sulfonic acid group as the hydrophilic group include diamines or polyamines containing an alkali metal sulfonate group, such as alkali metal salts of N-(2-aminoethyl)-2-aminoethanesulfonic acid. Examples of the compound having a sulfonic acid group as the hydrophilic group include polyol compounds obtained by esterifying the polyhydric alcohol with a compound having a sulfonic acid group, such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, or 5[4-sulfophenoxy]isophthalic acid.

[0041] Examples of the compound having a polyalkylene oxide structure as the hydrophilic group include polyethylene glycol, polypropylene glycol, a copolymer of ethylene oxide and propylene oxide, a copolymer of ethylene oxide and butylene oxide, a copolymer of ethylene oxide and another alkylene oxide, and monoalkyl ethers thereof.

[0042] These compounds (a3) ​​having a hydrophilic group can be used alone or in combination of two or more kinds.

[0043] The amount of the compound (a3) ​​having a hydrophilic group used is preferably in the range of 0.1 to 5 mass %, more preferably 0.5 to 3 mass %, of the total mass of the raw materials for the urethane resin (A), since an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance can be obtained.

[0044] Furthermore, in addition to the polyol compound (a1) and the polyisocyanate compound (a2), a chain extender (a4) can also be used as a raw material for the urethane resin (A), if necessary.

[0045] Examples of the chain extender (a4) include chain extenders having a hydroxyl group, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, trimethylolpropane, and glycerin; and chain extenders having an amino group, such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, aminoethylethanolamine, hydrazine, diethylenetriamine, and triethylenetetramine. These chain extenders can be used alone or in combination of two or more. Among these, a chain extender having a hydroxyl group is preferred, and ethylene glycol, diethylene glycol, 1,3-propanediol, and 1,4-butanediol are more preferred, as they can provide an aqueous urethane resin composition capable of forming a film with excellent moisture permeability and water resistance. Furthermore, bio-based ethylene glycol, bio-based 1,3-propanediol, bio-based 1,4-butanediol, etc. can also be used, as they can reduce the environmental impact.

[0046] The amount of the chain extender (a4) used is preferably in the range of 0.1 to 30 mass %, more preferably 1 to 10 mass %, of the total mass of the raw materials for the urethane resin (A), since an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance can be obtained.

[0047] The acid value of the urethane resin (A) is preferably in the range of 0.1 to 25 mgKOH / g, more preferably in the range of 1 to 10 mgKOH / g, because an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance can be obtained.

[0048] The ethylene oxide concentration in the urethane resin (A) is preferably in the range of 1 to 6 mmol / g, more preferably in the range of 1.5 to 5 mmol / g, because an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance can be obtained.

[0049] The method for producing the urethane resin (A) is not particularly limited, and any method may be used. For example, the urethane resin (A) may be produced by reacting all of the reactant materials, including the polyol compound (a1) and the polyisocyanate compound (a2), at once, or by reacting the reactant materials sequentially. These reactions are preferably carried out at a temperature of 50 to 100°C for 3 to 10 hours.

[0050] Examples of the aqueous medium (B) include ion-exchanged water, distilled water, etc. These aqueous media can be used alone or in combination of two or more.

[0051] The mass ratio [(A) / (B)] of the urethane resin (A) to the aqueous medium (B) is preferably in the range of 20 / 80 to 80 / 20, more preferably in the range of 30 / 70 to 70 / 30, since an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance can be obtained.

[0052] As the crosslinking agent (C), an epoxy-based crosslinking agent having a polyoxyethylene chain is used as an essential component.

[0053] Examples of the epoxy-based crosslinking agent having a polyoxyethylene chain include polyethylene glycol diglycidyl ether, polyoxyethylene polyoxypropylene glycol diglycidyl ether, etc. Among these, polyethylene glycol diglycidyl ether is preferred because it can provide an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance.

[0054] The polyethylene glycol diglycidyl ether preferably has a number average molecular weight in the range of 100 to 1,500, since this gives an aqueous urethane resin composition capable of forming a film having excellent moisture permeability and water resistance.

[0055] The amount of the crosslinking agent (C) used is preferably 0.5 parts by mass or more, more preferably 1 to 10 parts by mass, per 100 parts by mass of the total of the urethane resin (A) and the aqueous medium (B).

[0056] The method for producing the aqueous urethane resin composition is not particularly limited, and any method may be used for production. For example, there may be mentioned a method (Method 1) of mixing a urethane resin (A), an aqueous medium (B), and a crosslinking agent (C) to obtain the composition, a method (Method 2) of synthesizing a prepolymer by charging a polyol compound (a1), a polyisocyanate compound (a2), a compound having a hydrophilic group (a3), and a chain extender (a4) all at once and reacting them, and dispersing the prepolymer in an aqueous medium (B), followed by reacting the crosslinking agent (C), and a method (Method 3) of synthesizing a prepolymer having an isocyanate group by reacting the polyol compound (a1), a polyisocyanate compound (a2), and a compound having a hydrophilic group (a3), followed by reacting the chain extender (a4), dispersing the prepolymer in an aqueous medium (B), followed by reacting the crosslinking agent (C).

[0057] In the above (Method 1) to (Method 3), a neutralizing agent can be used if necessary.

[0058] Examples of methods for mixing the urethane resin (A), the aqueous medium (B), and the crosslinking agent (C) include methods using a reaction vessel equipped with a stirring blade; a kneader such as a kneader, a continuous kneader, a taper roll, a single-screw extruder, a twin-screw extruder, a triple-screw extruder, a universal mixer, a Plastomill, or a Bodeta-type kneader; a rotary dispersion mixer such as a homomixer, a static mixer, FILMICS, an Ebara Milder, a Clearmix, an Ultra-Turrax, a Cavitron, or a Biomixer; an ultrasonic dispersion device; or a device such as an in-line mixer that has no moving parts and can mix by the flow of the fluid itself.

[0059] The aqueous urethane resin composition of the present invention may contain other additives as needed.

[0060] Examples of the other additives include emulsifiers, thickeners, urethane catalysts, fillers, flame retardants, leveling agents, antiblocking agents, etc. These additives can be used alone or in combination of two or more.

[0061] Examples of the emulsifier include nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrylphenyl ether, polyoxyethylene sorbitol tetraoleate, and polyoxyethylene-polyoxypropylene copolymer; anionic emulsifiers such as fatty acid salts such as sodium oleate, alkyl sulfate ester salts, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, sodium alkanesulfonates, and sodium alkyldiphenyl ether sulfonates; and cationic emulsifiers such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts. These emulsifiers can be used alone or in combination of two or more.

[0062] Examples of the thickener include associative and acid thickeners.

[0063] Examples of the urethane catalyst include organotin catalysts and bismuth catalysts.

[0064] Examples of the filler include calcium carbonate and silica.

[0065] Examples of the flame retardant include phosphorus-based flame retardants.

[0066] Examples of the leveling agent include silicone-based leveling agents.

[0067] Examples of the anti-blocking agent include acrylic agents and cellulose ester agents.

[0068] The coating of the present invention is made of the aqueous urethane resin composition.

[0069] The coating may be formed, for example, by applying the aqueous urethane resin composition of the present invention to a substrate and then drying the aqueous medium.

[0070] Examples of the substrate include fiber substrates such as nonwoven fabrics, woven fabrics, and knitted fabrics made from polyester fibers, polyethylene fibers, nylon fibers, acrylic fibers, polyurethane fibers, acetate fibers, rayon fibers, polylactic acid fibers, cotton, hemp, silk, wool, glass fibers, carbon fibers, and blends thereof; nonwoven fabrics impregnated with resins such as polyurethane resins; nonwoven fabrics further provided with a porous layer; resin substrates; rubber; glass; wood; and metals.

[0071] Examples of methods for applying the aqueous urethane resin composition to the substrate include methods using a roll coater, knife coater, comma coater, applicator, and the like.

[0072] The method for drying the water includes, for example, drying at a temperature of 60 to 130° C. for 30 seconds to 10 minutes.

[0073] The thickness of the film obtained by the above method is, for example, 5 to 1,000 μm.

[0074] The articles of the present invention include those having the above-mentioned coating, and specific examples thereof include synthetic leather, artificial leather, moisture-permeable clothing, and moisture-permeable films.

[0075] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the examples given below.

[0076] (Synthesis Example 1: Synthesis of urethane resin aqueous dispersion (1)) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of polytetramethylene glycol (number average molecular weight: 2,000, hereinafter abbreviated as "PTMG"), 45 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=75 / 25, number average molecular weight: 1,100), 4 parts by mass of 2,2-dimethylolpropionic acid (hereinafter abbreviated as "DMPA"), and 171 parts by mass of methyl ethyl ketone (hereinafter abbreviated as "MEK") were added under a nitrogen stream and mixed uniformly. After that, 56 parts by mass of dicyclohexylmethane diisocyanate (hereinafter abbreviated as "HMDI") was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70°C for approximately 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0077] Next, 3.6 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 708 parts by mass of ion-exchanged water was added, followed by the addition of 11.9 parts by mass of isophorone diamine (hereinafter abbreviated as "IPDA"), and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (1). The anionic group concentration of this urethane resin aqueous dispersion (1) was 0.12 mmol / g, and the EO chain concentration was 3.5 mmol / g.

[0078] Synthesis Example 2 Synthesis of Urethane Resin Aqueous Dispersion (2) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 2,000), 34 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=75 / 25, number average molecular weight: 1,100), 3 parts by mass of DMPA, and 150 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 39 parts by mass of HMDI was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70° C. for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0079] Next, 1.9 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 615 parts by mass of ion-exchanged water was added, followed by 8.6 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (2). The anionic group concentration of this urethane resin aqueous dispersion (2) was 0.10 mmol / g, and the EO concentration was 3.05 mmol / g.

[0080] Synthesis Example 3 Synthesis of Urethane Resin Aqueous Dispersion (3) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 2,000), 50 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=75 / 25, number average molecular weight: 1,100), 3 parts by mass of DMPA, and 166 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 46 parts by mass of HMDI was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70° C. for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0081] Next, 2.6 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 674 parts by mass of ion-exchanged water was added, followed by 8 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (3). The anionic group concentration of this urethane resin aqueous dispersion (3) was 0.10 mmol / g, and the EO concentration was 4 mmol / g.

[0082] Synthesis Example 4 Synthesis of Urethane Resin Water Dispersion (4) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 3,000), 30 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=75 / 25, number average molecular weight: 1,100), 2 parts by mass of DMPA, and 141 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 37 parts by mass of HMDI was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70° C. for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0083] Next, 2.4 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 579 parts by mass of ion-exchanged water was added, followed by 7.9 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (4). The anionic group concentration of this urethane resin aqueous dispersion (4) was 0.10 mmol / g, and the EO concentration was 2.85 mmol / g.

[0084] Synthesis Example 5 Synthesis of Urethane Resin Water Dispersion (5) Under a nitrogen stream, 100 parts by mass of PTMG (number average molecular weight: 2,000), 35 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=50 / 50, number average molecular weight: 1,750), 3 parts by mass of DMPA, and 146 parts by mass of MEK were added to a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, and mixed uniformly. After that, 36 parts by mass of HMDI was added, and then 0.1 parts by mass of dibutyltin dilaurate was added, and the mixture was allowed to react at 70° C. for about 4 hours, thereby obtaining a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0085] Next, 2.3 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, followed by the addition of 590 parts by mass of ion-exchanged water, followed by the addition of 7.9 parts by mass of IPDA, and the mixture was allowed to react. The methyl ethyl ketone was then distilled off under reduced pressure, and 9.1 parts by mass of silicone emulsion (WACKER E22 manufactured by Wacker Asahi Kasei Silicones Co., Ltd., solids content: 42% by mass) was added to obtain a urethane resin aqueous dispersion (5). The anionic group concentration of this urethane resin aqueous dispersion (5) was 0.12 mmol / g, and the EO concentration was 2.13 mmol / g.

[0086] Synthesis Example 6 Synthesis of Urethane Resin Aqueous Dispersion (6) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 250 parts by mass of polyoxyethylene polyoxypropylene glycol (a block copolymer of EO and PO, [EO / PO]=10 / 90, number average molecular weight: 1,100), 9 parts by mass of DMPA, and 380 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 156 parts by mass of HMDI was added, and then 0.09 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70° C. for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0087] Next, 8.7 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 1601 parts by mass of ion-exchanged water was added, followed by 33 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (6). The anionic group concentration of this urethane resin aqueous dispersion (6) was 0.13 mmol / g, and the EO concentration was 1.98 mmol / g.

[0088] Synthesis Example 7 Synthesis of Urethane Resin Aqueous Dispersion (7) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 2,000), 39 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=75 / 25, number average molecular weight: 1,100), 4 parts by mass of DMPA, and 164 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 47 parts by mass of isophorone diisocyanate (hereinafter abbreviated as "IPDI") was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70°C for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having isocyanate groups.

[0089] Next, 3.6 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 680 parts by mass of ion-exchanged water was added, followed by the addition of 11.9 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (7). The anionic group concentration of this urethane resin aqueous dispersion (7) was 0.13 mmol / g, and the EO concentration was 3.65 mmol / g.

[0090] Synthesis Example 8 Synthesis of Urethane Resin Water Dispersion (8) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 2,000), 39 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=75 / 25, number average molecular weight: 1,100), 4 parts by mass of DMPA, and 154 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 36 parts by mass of hexamethylene diisocyanate (hereinafter abbreviated as "HDI") was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70°C for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having isocyanate groups.

[0091] Next, 3.6 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 643 parts by mass of ion-exchanged water was added, followed by the addition of 11.9 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (8). The anionic group concentration of this urethane resin aqueous dispersion (8) was 0.14 mmol / g, and the EO concentration was 3.86 mmol / g.

[0092] Synthesis Example 9 Synthesis of Urethane Resin Aqueous Dispersion (9) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 2,000), 33 parts by mass of polyoxyethylene glycol (number average molecular weight: 1,000, hereinafter abbreviated as "PEG"), 3 parts by mass of DMPA, and 160 parts by mass of MEK were added under a nitrogen stream and mixed uniformly. After that, 54 parts by mass of HMDI was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70°C for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0093] Next, 3.4 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 666 parts by mass of ion-exchanged water was added, followed by 11.6 parts by mass of IPDA, and the mixture was allowed to react. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (9). The anionic group concentration of this urethane resin aqueous dispersion (9) was 0.12 mmol / g, and the EO concentration was 3.65 mmol / g.

[0094] Synthesis Example 10 Synthesis of Urethane Resin Aqueous Dispersion (10) Under a nitrogen stream, 100 parts by mass of PTMG (number average molecular weight: 2,000), 2.2 parts by mass of PEG, 47 parts by mass of polyoxyethylene polyoxypropylene glycol (a random copolymer of EO and PO, [EO / PO]=50 / 50, number average molecular weight: 1,750), 3 parts by mass of DMPA, and 168 parts by mass of MEK were added to a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, and after uniformly mixing, 49 parts by mass of HMDI was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70° C. for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0095] Next, 2.9 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 695 parts by mass of ion-exchanged water was added, followed by 10.6 parts by mass of IPDA, and the mixture was allowed to react. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (10). The anionic group concentration of this urethane resin aqueous dispersion (10) was 0.10 mmol / g, and the EO concentration was 2.68 mmol / g.

[0096] Synthesis Example 11 Synthesis of Urethane Resin Aqueous Dispersion (11) In a four-neck flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 100 parts by mass of PTMG (number average molecular weight: 2,000), 2 parts by mass of DMPA, and 110 parts by mass of MEK were added under a nitrogen stream and mixed uniformly, and then 31 parts by mass of HMDI was added, and then 0.04 parts by mass of bismuth 2-ethylhexanoate was added, and the mixture was allowed to react at 70°C for about 4 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group.

[0097] Next, 2.0 parts by mass of triethylamine was added to neutralize the carboxyl groups in the urethane polymer, and then 453 parts by mass of ion-exchanged water was added, followed by the addition of 6.5 parts by mass of IPDA, and the reaction was allowed to proceed. The methyl ethyl ketone was then distilled off under reduced pressure to obtain a urethane resin aqueous dispersion (11). The anionic group concentration of this urethane resin aqueous dispersion (11) was 0.11 mmol / g, and the EO concentration was 0 mmol / g.

[0098] Table 1 shows the compositions, anionic group concentrations and EO concentrations of the urethane resin dispersions (1) to (11) obtained in the above synthesis examples.

[0099]

[0100] Example 1 Preparation of Aqueous Urethane Resin Composition (1) An aqueous urethane resin composition (1) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (1) obtained in Synthesis Example 1, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-850"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (1).

[0101] Example 2 Preparation of Aqueous Urethane Resin Composition (2) An aqueous urethane resin composition (2) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (1) obtained in Synthesis Example 1, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0102] Example 3 Preparation of Aqueous Urethane Resin Composition (3) An aqueous urethane resin composition (3) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (1) obtained in Synthesis Example 1, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-861"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0103] Example 4 Preparation of Aqueous Urethane Resin Composition (4) An aqueous urethane resin composition (4) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (2) obtained in Synthesis Example 2, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0104] Example 5 Preparation of Aqueous Urethane Resin Composition (5) An aqueous urethane resin composition (5) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (3) obtained in Synthesis Example 3, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0105] Example 6 Preparation of Aqueous Urethane Resin Composition (6) An aqueous urethane resin composition (6) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (4) obtained in Synthesis Example 4, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0106] Example 7 Preparation of Aqueous Urethane Resin Composition (7) An aqueous urethane resin composition (7) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (5) obtained in Synthesis Example 5, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0107] Example 8 Preparation of Aqueous Urethane Resin Composition (8) An aqueous urethane resin composition (8) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (6) obtained in Synthesis Example 6, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (8).

[0108] Example 9 Preparation of Aqueous Urethane Resin Composition (9) An aqueous urethane resin composition (9) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (7) obtained in Synthesis Example 7, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (9).

[0109] Example 10 Preparation of Aqueous Urethane Resin Composition (10) An aqueous urethane resin composition (10) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (8) obtained in Synthesis Example 8, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (10).

[0110] Example 11 Preparation of Aqueous Urethane Resin Composition (11) An aqueous urethane resin composition (11) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (9) obtained in Synthesis Example 9, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (11).

[0111] Example 12 Preparation of Aqueous Urethane Resin Composition (12) An aqueous urethane resin composition (12) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (10) obtained in Synthesis Example 10, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (12).

[0112] Comparative Example 1 Preparation of Aqueous Urethane Resin Composition (R1) An aqueous urethane resin composition (R1) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (1) obtained in Synthesis Example 1, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of a carbodiimide crosslinking agent (Nisshinbo Inc.'s "V-02-L2"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0113] Comparative Example 2: Preparation of aqueous urethane resin composition (R2) An aqueous urethane resin composition (R2) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (2) obtained in Synthesis Example 2, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of a carbodiimide crosslinking agent (Nisshinbo Inc.'s "V-02-L2"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF")

[0114] Comparative Example 3 Preparation of Aqueous Urethane Resin Composition (R3) An aqueous urethane resin composition (R3) was obtained by blending 100 parts by mass of the urethane resin aqueous dispersion (11) obtained in Synthesis Example 11, 0.6 parts by mass of a leveling agent (BYK Corporation's "BYK-3455"), 0.3 parts by mass of an antifoaming agent (BYK Corporation's "BYK-093"), 4 parts by mass of an epoxy-based crosslinking agent (Nagase Chemtec Corporation's polyoxyethylene chain-having epoxy-based crosslinking agent "Denacol EX-830"), and 0.5 parts by mass of a thickener (ADEKA Corporation's "ADEKA NOL UH-541VF") to obtain an aqueous urethane resin composition (R3).

[0115] The aqueous urethane resin compositions (1) to (12) and (R1) to (R3) obtained in the above Examples and Comparative Examples were evaluated as follows.

[0116] [Preparation of Test Pieces] The aqueous urethane resin compositions prepared in the Examples and Comparative Examples were applied to flat release paper so that the film thickness after drying would be 20 μm, and then dried at 70° C. for 4 minutes and at 120° C. for 5 minutes to obtain thin films (test pieces).

[0117] [Method for evaluating moisture permeability] The moisture permeability was measured based on the test method of JIS-L-1099 (2012). Specifically, calcium chloride was added to a moisture permeability cup, the coated surface of the test piece was placed on the calcium chloride side, the moisture permeability cup was set, and this was placed in a thermo-hygrostat at 40°C and 90% RH. After 1 hour of humidity control, the sample was weighed. The sample was then placed in the same apparatus again, and after another 1 hour, the sample was weighed. The mass of water vapor that had passed through the sample and been absorbed by the moisture absorbent in the cup was calculated to obtain the moisture permeability (g / m ２ / 24h) was calculated and the moisture permeability was evaluated according to the following criteria.

[0118] A: In a film having a thickness of less than 20 μm after drying, the moisture permeability is 5,000 (g / m ２ B: In a film having a thickness of less than 20 μm after drying, the moisture permeability was 3,000 (g / m ２ / 24h) or more 5,000 (g / m ２ C: In a film having a thickness of less than 20 μm after drying, the moisture permeability was less than 3,000 (g / m ２ / 24h).

[0119] [Method for evaluating water resistance] Water pressure resistance was measured based on the test method of JIS-L-1092 (2020). Specifically, the test piece was fixed to a measuring machine and measurement was started. Water pressure was applied to the measurement sample at a pressure increase rate of 100 kPa / min, and the measurement was completed when water seeped out of the measurement sample at three locations. Water resistance was evaluated according to the following criteria.

[0120] A: For a film with a thickness of less than 20 μm after drying, the water pressure resistance is 10,000 (mmH ２ B: For a film having a thickness of less than 20 μm after drying, the water pressure resistance was 5,000 (mmH ２ O) or more than 10,000 (mmH ２ C: For a film having a thickness of less than 20 μm after drying, the water pressure resistance was less than 5,000 (mmH ２ O).

[0121] Tables 2 and 3 show the evaluation results of the aqueous urethane resin compositions (1) to (12) and (R1) to (R3) obtained in the above Examples and Comparative Examples.

[0122]

[0123]

[0124] From the evaluation results in Table 2 above, it was confirmed that the aqueous urethane resin composition of the present invention is capable of forming a film having excellent moisture permeability and water resistance.

[0125] On the other hand, Comparative Examples 1 and 2 shown in Table 3 are examples in which a crosslinking agent other than the crosslinking agent specified in the present invention (a carbodiimide-based crosslinking agent) was used, and it was confirmed that the moisture permeability was insufficient and that the film did not have both moisture permeability and water resistance.

[0126] Comparative Example 3 is an example in which the polyol compound (a1) defined in the present invention is not used, but like Comparative Examples 1 and 2, it was confirmed that the moisture permeability was insufficient and that the composition did not have both moisture permeability and water resistance.

Claims

1. An aqueous urethane resin composition comprising a urethane resin (A), an aqueous medium (B), and a crosslinking agent (C), wherein the urethane resin (A) comprises, as essential raw materials, a polyol compound (a1) containing polyoxyethylene glycol (a1-1) and / or polyoxyethylene polyoxypropylene glycol (a1-2), and a polyisocyanate compound (a2), and the crosslinking agent (C) contains an epoxy-based crosslinking agent having a polyoxyethylene chain.

2. The aqueous urethane resin composition according to claim 1, wherein the ethylene oxide concentration in the urethane resin (A) is in the range of 1 to 6 mmol / g.

3. The aqueous urethane resin composition according to claim 1, wherein the polyol compound (a1) further contains a polyether polyol other than the polyoxyethylene glycol (a1-1) and the polyoxyethylene polyoxypropylene glycol (a1-2).

4. An aqueous urethane resin composition according to claim 1, wherein the amount of the crosslinking agent (C) used is 0.5 parts by mass or more per 100 parts by mass of the total of the urethane resin (A) and the aqueous medium (B).

5. The aqueous urethane resin composition according to claim 1, wherein the epoxy-based crosslinking agent having a polyoxyethylene chain is polyethylene glycol diglycidyl ether.

6. The aqueous urethane resin composition according to claim 5, wherein the number average molecular weight of said polyethylene glycol diglycidyl ether is in the range of 100 to 1,500.

7. A coating formed from the aqueous urethane resin composition according to any one of claims 1 to 6.

8. An article comprising the coating of claim 7.

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