JP2020105237A - Polyurethane resin aqueous dispersion - Google Patents

Abstract

To provide a polyurethane resin aqueous dispersion capable of forming an adhesive layer excellent in adhesion between a base material and a functional layer and thermal yellowing resistance.SOLUTION: A polyurethane resin aqueous dispersion (Q) contains: a polyurethane resin (U) that is a reactant of an isocyanate group-terminated prepolymer (P) containing a polymer polyol (a) having a number average molecular weight of 500 or more and organic polyisocyanate (b) as essential constituent monomers, a chain extender (e) and a terminal blocking agent (s) and has a ratio of the number of mols of the terminal blocking agent (s) to the number of mols of the isocyanate group of the prepolymer (P) of 0.25-0.75; and an aqueous medium.SELECTED DRAWING: None

Description

The present invention relates to an aqueous polyurethane resin dispersion.

The optically functional film used for a liquid crystal display is composed of a plurality of layers having respective functions. Polyethylene terephthalate (PET) is mainly used as a base material in terms of transparency, dimensional stability, chemical resistance and price, and a functional layer such as a protective (hard coat) layer or an antireflection layer is laminated on this. Generally, a PET film is biaxially stretched in order to exhibit the above-mentioned properties, but has a high degree of crystal orientation, and thus has poor adhesion to the functional layer. Therefore, an adhesive layer is formed on the PET film, and the functional layer is laminated thereon. As the adhesive layer, a polyurethane resin is often used because it has excellent flexibility, adhesion, chemical resistance, mechanical strength, and impact resistance (see, for example, Patent Documents 1 and 2).
The in-line coating method is frequently used for the optical functional film having a PET film as a base material from the viewpoint of performance. That is, a water-based adhesive resin is applied on an unstretched or uniaxially stretched PET film, followed by heat treatment, and further uniaxially stretched to crystallize PET (see, for example, Patent Document 3).
However, since this heat treatment is carried out at a high temperature, there is a problem that the adhesive layer is thermally yellowed and the optical performance is adversely affected.

Japanese Patent No. 4770971 Japanese Patent No. 5651954 JP 2001-341262 A

The present invention has been made in view of the above problems, and an object of the present invention is to provide a polyurethane resin aqueous dispersion capable of forming an adhesive layer excellent in adhesion between a substrate and a functional layer and heat yellowing. To do.

The present inventors have arrived at the present invention as a result of extensive studies to achieve the above object. That is, the present invention relates to an isocyanate group-terminated prepolymer (P) containing a high-molecular-weight polyol (a) having a number average molecular weight of 500 or more and an organic polyisocyanate (b) as essential constituent monomers, a chain extender (e), and a terminal. In the reaction product with the capping agent (s), the ratio of the number of moles of the terminal blocking agent (s) to the number of moles of the isocyanate group of the prepolymer (P) is 0.25 to 0.75. A polyurethane resin aqueous dispersion (Q) containing a certain polyurethane resin (U) and an aqueous medium; a multilayer film having a dry film of the polyurethane resin aqueous dispersion (Q) on at least one surface of a polyester film.

The dry film of the polyurethane resin aqueous dispersion of the present invention is excellent in adhesion between the base material and the functional layer and heat yellowing.

The polyurethane resin aqueous dispersion (Q) of the present invention comprises a high-molecular polyol (a) having a number average molecular weight (hereinafter abbreviated as Mn) of 500 or more and an isocyanate group containing an organic polyisocyanate (b) as essential constituent monomers. It contains a polyurethane resin (U), which is a reaction product of a terminal prepolymer (P), a chain extender (e), and a terminal blocking agent (s), and an aqueous medium.

Examples of the polyol (a) having Mn of 500 or more include polyester polyol (a1), polyether polyol (a2), and polyether polyester polyol (a3).

As the polyester polyol (a1), a polylactone polyol (a11), a polycarbonate polyol (a12), a polyester polyol (a13) having a carboxylic acid ester group and a carbonic acid ester group, and a polyhydric alcohol and a polyvalent carboxylic acid or ester formation thereof Examples thereof include polyester polyols (a14) having only a monomeric derivative as a constituent monomer.

As the polylactone polyol (a11), a lactone monomer having 3 to 12 carbon atoms (β-propiolactone, γ-butyrolactone, γ-valerolactone, ε-caprolactone, a polyhydric alcohol having 2 to 20 carbon atoms as an initiator, Examples include those obtained by ring-opening polymerization of η-caprylolactone, 11-undecanolactone, 12-tridecanoide and the like. The lactone monomers may be used alone or in combination of two or more.

As the polyhydric alcohol having 2 to 20 carbon atoms, a linear or branched aliphatic dihydric alcohol having 2 to 12 carbon atoms [ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5- Direct addition of pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, diethylene glycol, triethylene glycol and tetraethylene glycol. Chain alcohol; 1,2-, 1,3- or 2,3-butanediol, 2-methyl-1,4-butanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2- Methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,6-hexanediol, 3-methyl-1,6-hexanediol, 2-methyl-1,7- Heptanediol, 3-methyl-1,7-heptanediol, 4-methyl-1,7-heptanediol, 2-methyl-1,8-octanediol, 3-methyl-1,8-octanediol and 4-methyl Branched alcohols such as octanediol, etc.; alicyclic dihydric alcohols having 6 to 20 carbon atoms [1,4-cyclohexanediol, 1,3- or 1,4-cyclohexanedimethanol, 1,3-cyclopentanediol, 1,4-cycloheptanediol, 2,5-bis(hydroxymethyl)-1,4-dioxane, 2,7-norbornanediol, tetrahydrofuran dimethanol, 1,4-bis(hydroxyethoxy)cyclohexane, 1,4- Bis(hydroxymethyl)cyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane, etc.]; Aroaliphatic dihydric alcohol having 8 to 20 carbon atoms [m- or p-xylylenediol, bis(hydroxyethyl)benzene And bis(hydroxyethoxy)benzene, etc.]; C3-C20 trihydric alcohols [aliphatic triols (glycerin, trimethylolpropane, etc.)]; C5-C20 4-octahydric alcohols (aliphatic polyols ( Pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipentaerythritol, etc.); sugars (sucrose, glucose, mannose, fructose, methylglucoside and its derivatives)]; and the like.

As the polycarbonate polyol (a12), one type or two or more types (preferably 2 to 4 types) of the polyhydric alcohol having 2 to 20 carbon atoms and a low molecular weight carbonate compound (for example, 1 to 6 carbon atoms of an alkyl group). Dialkyl carbonate, an alkylene carbonate having an alkylene group having 2 to 6 carbon atoms, and a diaryl carbonate having an aryl group having 6 to 9 carbon atoms) or a mixture of two or more thereof, and is produced by condensation while performing a dealcoholization reaction. Polycarbonate polyol and the like.

Among the polyhydric alcohols used in (a12), dihydric alcohols are preferable from the viewpoint of tensile strength and elongation of the polyurethane resin (U), and more preferable are aliphatic dihydric alcohols having 2 to 8 carbon atoms. Is.

Examples of the polyester polyol (a13) having a carboxylic acid ester group and a carbonic acid ester group include the polyhydric alcohol having 2 to 20 carbon atoms, the polyhydric carboxylic acid having 2 to 10 carbon atoms or its ester-forming derivative and the low-molecular weight compound. Examples thereof include those obtained by reacting a carbonate compound and those obtained by ring-opening polymerization of the above-mentioned lactone monomer having 3 to 12 carbon atoms with the above-mentioned polycarbonate polyol (a12).

Examples of the polycarboxylic acid having 2 to 10 carbon atoms or its ester-forming derivative include aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, etc.), alicyclic dicarboxylic acids ( Dimer acid, etc.), aromatic dicarboxylic acid (terephthalic acid, isophthalic acid, phthalic acid, etc.), trivalent or higher polycarboxylic acid (trimellitic acid, pyromellitic acid, etc.), and their anhydrides (succinic anhydride, Maleic anhydride, phthalic anhydride, trimellitic anhydride, etc.), acid halides thereof (adipic acid dichloride, etc.), low molecular weight alkyl esters thereof (dimethyl succinate, dimethyl phthalate, etc.), and combinations thereof. ..

Examples of the polyester polyol (a14) containing only a polyhydric alcohol and a polycarboxylic acid or an ester-forming derivative thereof as a constituent monomer include the polyhydric alcohol having 2 to 20 carbon atoms and the polyhydric alcohol having 2 to 10 carbon atoms. Examples thereof include those reacted with a carboxylic acid or an ester-forming derivative thereof.

Examples of the polyether polyol (a2) include compounds obtained by adding an alkylene oxide having 2 to 12 carbon atoms (hereinafter abbreviated as AO) to the polyhydric alcohol having 2 to 20 carbon atoms. One type of AO may be used alone or two or more types may be used in combination. In the latter case, block addition (chip type, balance type, active secondary type, etc.), random addition, or a combination of these may be used.

As AO having 2 to 12 carbon atoms, ethylene oxide, 1,2- or 1,3-propylene oxide, 1,2-, 1,3- or 2,3-butylene oxide, tetrahydrofuran, 3-methyltetrahydrofuran, styrene Oxides, α-olefin oxides, epichlorohydrin and the like can be mentioned.

Specific examples of the polyether polyol (a2) include poly(oxyethylene)glycol, poly(oxypropyleneg)glycol, poly(oxytetramethylene)glycol, poly(oxy-3-methyltetramethylene)glycol, and tetrahydrofuran/ethylene. Examples thereof include oxide copolymer diol and tetrahydrofuran/3-methyltetrahydrofuran copolymer diol.

As the polyether polyester polyol (a3), one or more kinds of polyether polyols having the same composition as the polyether polyol (a2) and one kind of the polyvalent carboxylic acid having 2 to 10 carbon atoms or the ester-forming derivative thereof. Examples thereof include those obtained by polycondensation of the above.

Among the polyols (a), preferable from the viewpoint of heat-resistant yellowing are polylactone polyols (a11), polycarbonate polyols (a12) and polyester polyols (a13) having a carboxylic acid ester group and a carbonic acid ester group. Of these, diols are preferred. As the polyol (a), one type may be used alone, or two or more types may be used in combination.

From the viewpoint of tensile strength and elongation of the polyurethane resin (U), Mn of the polyol (a) is 500 or more, preferably 500 to 10,000, more preferably 1,000 to 5,000, and particularly preferably 1,500. ~3,000.
The Mn in the present invention can be measured by gel permeation chromatography, for example, under the following conditions.
Device: "Waters Alliance 2695" [manufactured by Waters]
Column: "Guardcolumn Super HL" (one), "TSKgel SuperH2000, TSKgel SuperH3000, TSKgel SuperH4000 (all manufactured by Tosoh Corp.) connected to each one"
Sample solution: Tetrahydrofuran solution solution of 0.25 wt% Injection volume: 10 μl
Flow rate: 0.6 ml/min Measuring temperature: 40°C
Detector: Refractive index detector Reference substance: Standard polyethylene glycol

As the organic polyisocyanate (b), a chain aliphatic polyisocyanate having 4 to 22 carbon atoms (b1) having 2 to 3 or more isocyanate groups, and an alicyclic polyisocyanate having 8 to 18 carbon atoms (b2) ), an aromatic polyisocyanate having 8 to 26 carbon atoms (b3), an araliphatic polyisocyanate having 10 to 18 carbon atoms (b4), and a modified product (b5) of these polyisocyanates. As the organic polyisocyanate (b), one type may be used alone, or two or more types may be used in combination.

Examples of the chain aliphatic polyisocyanate having 4 to 22 carbon atoms (b1) include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate. 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate and 2-isocyanato Ethyl-2,6-diisocyanatohexanoate may be mentioned.

Examples of the alicyclic polyisocyanate (b2) having 8 to 18 carbon atoms include isophorone diisocyanate (hereinafter abbreviated as IPDI), 4,4′-dicyclohexylmethane diisocyanate (hereinafter abbreviated as hydrogenated MDI), cyclohexylene diisocyanate, Mention may be made of methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate and 2,5- or 2,6-norbornane diisocyanate.

Examples of the aromatic polyisocyanate having 8 to 26 carbon atoms (b3) include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (hereinafter abbreviated as TDI), and crude TDI. , 4,4'- or 2,4'-diphenylmethane diisocyanate (hereinafter abbreviated as MDI), crude MDI, polyaryl polyisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4 '-Diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4"-triphenylmethane triisocyanate and m- or p -Isocyanatophenylsulfonyl isocyanate.

Examples of the araliphatic polyisocyanate having 10 to 18 carbon atoms (b4) include m- or p-xylylene diisocyanate and α,α,α′,α′-tetramethylxylylene diisocyanate.

Examples of modified polyisocyanates (b5) of (b1) to (b4) include modified products of the above polyisocyanates (urethane group, carbodiimide group, alohanate group, urea group, biuret group, uretdione group, uretoimine group, isocyanurate group. Or an oxazolidone group-containing modified product; a free isocyanate group content of 8 to 33% by weight, preferably 10 to 30% by weight, particularly 12 to 29% by weight, such as modified MDI (urethane-modified MDI, carbodiimide-modified MDI and Trihydrocarbyl phosphate-modified MDI), urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI, and isocyanurate-modified IPDI.

Among the organic polyisocyanates (b), preferred are (b1) and (b2), more preferred are (b2), and particularly preferred are IPDI and hydrogenated from the viewpoints of mechanical strength and heat-resistant yellowing of the resulting film. It is MDI.

The chain extender (e) used in the polyurethane resin (U) includes a chain extender (e1) that reacts with the isocyanate group-terminated prepolymer (P) and, if necessary, a high amount during the synthesis of the isocyanate group-terminated prepolymer (P). There is a chain extender (e2) used in combination with the molecular polyol (a) and the organic polyisocyanate (b).

As the chain extender (e1) to be reacted with the isocyanate group-terminated prepolymer (P), water, a diamine having 2 to 10 carbon atoms (for example, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine and piperazine), carbon Examples include polyalkylene polyamines having a number of 2 to 10 (for example, diethylenetriamine, triethylenetetramine and tetraethylenepentamine), and hydrazine and its derivatives (dibasic acid dihydrazide such as adipic acid dihydrazide).

Examples of the chain extender (e2) include the same as those exemplified as the chain extender (e1) and the polyhydric alcohol having 2 to 20 carbon atoms.
As the chain extender (e), one type may be used alone, or two or more types may be used in combination.

In order to impart water dispersibility to the isocyanate group-terminated prepolymer (P), an ionic group may be introduced using a compound (c) having an ionic group and an active hydrogen atom. As for (c), one type may be used alone, or two or more types may be used in combination.

Examples of the compound (c) having an ionic group and an active hydrogen atom include a compound (c1) having an anionic group and an active hydrogen atom, and a compound (c2) having a cationic group and an active hydrogen atom.
Examples of the compound (c1) having an anionic group and an active hydrogen atom include a compound having a carboxyl group as an anionic group and having a carbon number of 2 to 10 [dialkylolalkanoic acid (eg, 2,2-dimethylolpropion). Acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolheptanoic acid and 2,2-dimethyloloctanoic acid), tartaric acid and amino acids (eg glycine, alanine and valine), etc.], and sulfonic acid as an anionic group A compound containing a group and having 2 to 16 carbon atoms [3-(2,3-dihydroxypropoxy)-1-propanesulfonic acid, sulfoisophthalic acid di(ethylene glycol) ester, etc.], a sulfamic acid group as an anionic group And a compound having 2 to 10 carbon atoms [N,N-bis(2-hydroxylethyl)sulfamic acid and the like] and salts obtained by neutralizing these compounds with a neutralizing agent.

Examples of the neutralizing agent used for the salt of (c1) include ammonia, amine compounds having 1 to 20 carbon atoms, and alkali metal hydroxides (sodium hydroxide, potassium hydroxide, lithium hydroxide, etc.).
Examples of the amine compound having 1 to 20 carbon atoms include primary amines such as monomethylamine, monoethylamine, monobutylamine and monoethanolamine, and secondary amines such as dimethylamine, diethylamine, dibutylamine, diethanolamine and diisopropanolamine, methylpropanolamine. Examples include amines and tertiary amines such as trimethylamine, triethylamine, dimethylethylamine, dimethylmonoethanolamine and triethanolamine.
The neutralizing agent used in the salt of (c1) may be used alone or in combination of two or more kinds.

As the neutralizing agent used for the salt of (c1), a compound having a high vapor pressure at 25° C. is suitable from the viewpoint of the drying property of the resulting polyurethane resin aqueous dispersion and the water resistance of the obtained film. From such a viewpoint, as the neutralizing agent used for the salt of (c1), ammonia, monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine and dimethylethylamine are preferable.

Among (c1), 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and salts thereof are preferable from the viewpoint of the resin physical properties of the obtained film and the dispersion stability of the polyurethane resin aqueous dispersion. And more preferred are neutralized salts of 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid with ammonia or an amine compound having 1 to 20 carbon atoms.

Examples of the compound (c2) containing a cationic group and an active hydrogen atom include a compound having a tertiary amino group as a cationic group and a hydroxyl group as an active hydrogen atom, a tertiary amino group having 1 to 20 carbon atoms. Diol [N-alkyldialkanolamine (eg N-methyldiethanolamine, N-propyldiethanolamine, N-butyldiethanolamine and N-methyldipropanolamine) and N,N-dialkylmonoalkanolamine (eg N,N-dimethylethanolamine ) Etc.] and other compounds are neutralized with a neutralizing agent.

Examples of the neutralizing agent used in (c2) include monocarboxylic acids having 1 to 10 carbon atoms (for example, formic acid, acetic acid, propanoic acid, etc.), carbonic acid, dimethyl carbonate, dimethyl sulfate, methyl chloride and benzyl chloride. ..
The neutralizing agent used in the salt (c2) may be used alone or in combination of two or more.

The neutralizing agent used in (c1) and (c2) is added at any time before the urethanization reaction, during the urethanization reaction, after the urethanization reaction, before the water dispersion step, during the water dispersion step, or after the water dispersion step. However, from the viewpoint of the stability of the polyurethane resin (U) and the stability of the aqueous dispersion, it is preferably added before or during the water dispersion step. Further, the neutralizing agent component volatilized during the solvent removal may be additionally added after the solvent removal, and the neutralizing agent additionally added may be the same as or different from the volatilized neutralizing agent.

Examples of the terminal blocking agent (s) used for the polyurethane resin (U) include monohydric alcohols having 1 to 10 carbon atoms (methanol, ethanol, isopropanol, benzyl alcohol, ethyl cellosolve, carbitol, etc.) and 1 to 10 carbon atoms. Monoamines (monomethylamine, monoethylamine, monobutylamine, dibutylamine, monooctylamine, and other mono- or dialkylamines; monoethanolamine, diethanolamine, diisopropanolamine, and other mono- or dialkanolamines).

Among these, monoamines having 1 to 10 carbon atoms are preferable, and monoethanolamine and diethanolamine are more preferable, from the viewpoint of rapidly reacting with the terminal isocyanate group of the prepolymer (P) to enhance the reproducibility of production. As the terminal blocking agent (s), one type may be used alone, or two or more types may be used in combination.

The method for producing the polyurethane resin aqueous dispersion (Q) of the present invention is not particularly limited, and for example, it can be produced by the following production method [1] or [2].

Production method [1]: a compound (c) having a polyol (a) and an organic polyisocyanate (b) as essential constituent monomers, and optionally having an ionic group and an active hydrogen atom, a chain extender (e2), and After carrying out a urethanization reaction using an organic solvent to obtain an isocyanate-terminated prepolymer (P), when (c) is used, a neutralizing agent is mixed at a predetermined weight ratio and then dispersed in an aqueous medium, A method in which P) is reacted with the terminal blocking agent (s), and then an extension reaction with a chain extender (e1) is performed.

Production method [2]: a compound (c) having a polyol (a) and an organic polyisocyanate (b) as essential constituent monomers, and optionally having an ionic group and an active hydrogen atom, a chain extender (e2), and After carrying out a urethanization reaction using an organic solvent to obtain an isocyanate-terminated prepolymer (P), the end-capping agent (s) is reacted, and when (c) is used, the neutralizing agent is added to a predetermined weight. A method in which the components are mixed in a ratio and then dispersed in an aqueous medium to carry out an elongation reaction with a chain extender (e1).

Examples of the organic solvent used in the reaction include ketone solvents (eg acetone and methyl ethyl ketone), ester solvents (eg ethyl acetate), ether solvents (eg tetrahydrofuran), amide solvents (eg N,N-dimethylformamide and N). -Methylpyrrolidone) and aromatic hydrocarbon solvents (for example, toluene) and the like.
Examples of the aqueous medium include water, a mixture of water and the organic solvent, and a mixture of water and an alcohol solvent (for example, methanol, ethanol and isopropyl alcohol).
The organic solvent used in the reaction and the organic solvent used in the aqueous medium may be used alone or in combination of two or more.

The neutralizing agent in the production methods [1] and [2] is preferably premixed with the isocyanate-terminated prepolymer (P) or an organic solvent solution thereof, but is added to an aqueous medium together with (P) or an organic solvent solution thereof. Alternatively, it may be mixed with an aqueous medium.

As the terminal blocking agent (s) in the production method [1], it is necessary to use a monoamine having 1 to 10 carbon atoms in order to react the isocyanate group more quickly than water. As the terminal blocking agent (s) in the production method [2], either a monohydric alcohol having 1 to 10 carbon atoms or a monoamine having 1 to 10 carbon atoms can be used.

The isocyanate group content of the isocyanate group-terminated prepolymer (P) is preferably from 2 from the viewpoint of handleability of the prepolymer (P) during production and the adhesive strength of the adhesive layer obtained from the polyurethane resin aqueous dispersion (Q). It is 4% by weight.

From the viewpoint of heat-resistant yellowing of the dry film of the polyurethane resin aqueous dispersion (Q), the ratio of the number of moles of the terminal blocking agent (s) to the number of moles of the isocyanate group of the isocyanate-terminated prepolymer (P) is 0.25. It is necessary to be 0.75, preferably 0.30 to 0.70, and more preferably 0.40 to 0.60.

The isocyanate-terminated prepolymer (P) in the present invention comprises a polyol (a), an organic polyisocyanate (b), and optionally a compound (c) having an ionic group and an active hydrogen atom, a chain extender (e2) and an organic solvent. It can be obtained by heating in a heatable facility to carry out a urethanization reaction. For example, a method of charging a raw material of an isocyanate-terminated prepolymer (P) into a container, uniformly stirring the mixture, and then heating the mixture in a heating dryer or a heating furnace without stirring, a simple pressure reactor (autoclave), Kolben, uniaxial or A method in which a reaction is performed by heating while stirring or kneading with a biaxial kneader, plastomill, universal kneader, or the like can be used. Among them, the method of reacting by heating while stirring or kneading tends to increase the homogeneity of the isocyanate-terminated prepolymer (P) to be obtained and to further improve the mechanical properties and durability of the obtained film. preferable.

The reaction temperature in producing the isocyanate-terminated prepolymer (P) is preferably 60 to 120° C., more preferably 60 to 110° C., from the viewpoint of reducing the content of the alohanate group and the burette group of (P). , Most preferably 60 to 100°C. The time for producing (P) can be appropriately selected depending on the equipment used, but is generally preferably 1 minute to 100 hours, more preferably 3 minutes to 30 hours, and particularly preferably It is 5 minutes to 20 hours. Within this range, it is possible to obtain (P) which can sufficiently exert the effect of the present invention.

It is also possible to use a known urethanization catalyst in order to accelerate the urethanization reaction when producing the isocyanate group-terminated prepolymer (P).

Examples of the urethanization catalyst include metal catalysts [tin-based (trimethyltin laurate, trimethyltin hydroxide, dimethyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, stannas octoate and dibutyltin maleate), lead-based (olein). Lead acid, lead 2-ethylhexanoate, lead naphthenate and lead octenoate, etc.), cobalt type (cobalt naphthenate etc.), bismuth type {bismuth tris(2-ethylhexanoate etc.) and mercury type (phenyl mercury propione). Acid salts, etc.), amine catalysts [triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, diazabicycloalkene {1,8-diazabicyclo[5.4.0]-7-undecene}, etc.; dialkylaminoalkyl Amines {dimethylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminoethylamine, dimethylaminooctylamine and dipropylaminopropylamine, etc.] or heterocyclic aminoalkylamines [2-(1-aziridinyl)ethylamine and 4- [1-piperidinyl)-2-hexylamine and the like] carbonates or organic acid salts (formate and the like) and the like; N-methylmorpholine, N-ethylmorpholine, triethylamine, diethylethanolamine, dimethylethanolamine and the like], and these And a mixture of two or more thereof.
The urethanization catalyst may be used alone or in combination of two or more.

The amount of the reaction catalyst used is preferably 1% or less, more preferably 0.001 to 0.1%, based on the weight of the isocyanate-terminated prepolymer (P) obtained.

In dispersing the isocyanate-terminated prepolymer (P) or its organic solvent solution in an aqueous medium, the dispersibility of the (P) or its organic solvent solution and the stability of the aqueous dispersion, and the mechanical strength of the dry film of (Q) From the viewpoint, it is preferable to use the compound (c) having an ionic group and an active hydrogen atom, but instead of (c) or together with (c), a dispersant (h) is used (P) or an organic solvent thereof. It is also possible to disperse the solution in an aqueous medium.

Examples of the dispersant (h) include a nonionic surfactant (h1), an anionic surfactant (h2), a cationic surfactant (h3), an amphoteric surfactant (h4) and other emulsifying dispersants (h5). ) Is mentioned. (H) may be used alone or in combination of two or more.

Examples of (h1) include AO addition type nonionic surfactants and polyhydric alcohol type nonionic surfactants. As the AO addition type, EO addition product of aliphatic alcohol having 10 to 20 carbon atoms, EO addition product of phenol, EO addition product of nonylphenol, EO addition product of alkylamine having 8 to 22 carbon atoms and EO addition product of polypropylene glycol Examples of the polyhydric alcohol type include polyhydric (3 to 8 valent or higher) alcohol (C2 to C30) fatty acid (C8 to C24) ester (for example, glycerin monostearate, glycerin). Examples thereof include monooleate, sorbitan monolaurate and sorbitan monooleate) and alkyl (C4-24) poly(degree of polymerization 1-10) glycosides.

Examples of (h2) include ether carboxylic acids having a hydrocarbon group having 8 to 24 carbon atoms or salts thereof [sodium lauryl ether acetate and sodium (poly)oxyethylene (additional mol number 1 to 100) lauryl ether acetate, etc.]; Sulfuric acid ester or ether sulfuric acid ester having a hydrocarbon group having 8 to 24 carbon atoms and salts thereof [sodium lauryl sulfate, (poly)oxyethylene (addition mole number 1 to 100) sodium lauryl sulfate, (poly)oxyethylene (addition Lauryl sulfate triethanolamine and (poly)oxyethylene (additional mol number 1 to 100) coconut oil fatty acid monoethanolamide sodium sulfate, etc.]; sulfonate having a hydrocarbon group having 8 to 24 carbon atoms [Sodium dodecylbenzene sulfonate, etc.]; Sulfosuccinate having one or two hydrocarbon groups having 8 to 24 carbon atoms; Phosphoric acid ester or ether phosphate having a hydrocarbon group having 8 to 24 carbon atoms and those [Sodium lauryl phosphate and (poly)oxyethylene (additional mole number 1 to 100) sodium lauryl ether phosphate and the like]; fatty acid salt having a hydrocarbon group having 8 to 24 carbon atoms [sodium laurate and trilaurate Ethanolamine and the like]; and acylated amino acid salts having a hydrocarbon group having 8 to 24 carbon atoms [coconut oil fatty acid methyl taurine sodium, coconut oil fatty acid sarcosine sodium, coconut oil fatty acid sarcosine triethanolamine, N-coconut oil fatty acid acyl- L-glutamic acid triethanolamine, N-coconut oil fatty acid acyl-L-glutamic acid sodium salt, and lauroylmethyl-β-alanine sodium salt].

Examples of (h3) include quaternary ammonium salt type [stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride and lanolin fatty acid aminopropylethyldimethylammonium ethyl sulfate] and amine salt type [diethylaminoethyl stearate]. Amide lactate, dilaurylamine hydrochloride, oleylamine lactate and the like].

Examples of (h4) include betaine-type amphoteric surfactants [coconut oil fatty acid amide propyl dimethylamino acetic acid betaine, lauryl dimethyl amino acetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, lauryl hydroxy. Sulfobetaine and lauroylamidoethyl hydroxyethyl carboxymethyl betaine hydroxypropyl sodium phosphate, etc.] and amino acid type amphoteric surfactants [sodium β-laurylaminopropionate etc.].

Examples of (h5) include polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as carboxymethyl cellulose, methyl cellulose and hydroxyethyl cellulose, carboxyl group-containing (co)polymers such as sodium polyacrylate, and US Pat. No. 5,906,704. Examples thereof include the emulsifying dispersant having a urethane group or an ester group as described above [for example, polylactone polyol and polyether diol linked with polyisocyanate].

The dispersant (h) is added before the urethane reaction of the isocyanate-terminated prepolymer (P), during the urethane reaction, after the urethane reaction, before the water dispersion step, during the water dispersion step, or after the water dispersion. From the viewpoint of the dispersibility of the isocyanate-terminated prepolymer (P) or its organic solvent solution and the stability of the aqueous dispersion, it may be added before or during the water dispersion step of (P) or its organic solvent solution. It is preferable to add.

The amount of (h) used is preferably 0.01 to 20% by weight, more preferably 0.01 to 10% by weight, further preferably 0.1 to 5% by weight, based on the weight of the polyurethane resin (U). ..

As an apparatus for dispersing the isocyanate-terminated prepolymer (P) or its organic solvent solution in water, any apparatus having dispersion capacity (A) can be used, but from the viewpoint of temperature adjustment and dispersion capacity, etc. It is preferable to use the dispersion mixer (A1), the ultrasonic disperser (A2) or the kneader (A3), and among them, (A1) having particularly excellent dispersibility is more preferable.

The main dispersion principle of the rotary dispersion mixer (A1) is to apply a shearing force to the object to be processed from the outside by means of rotation of a driving unit or the like to atomize and disperse the particles. Further, (A1) can be operated under normal pressure, reduced pressure or increased pressure.

As the rotary dispersion mixer (A1), for example, a mixer having a general stirring blade such as Maxblend or a helical blade, TK Homomixer [manufactured by PRIMIX Corporation], CLEARMIX [manufactured by M Technique Co., Ltd.] , Filmix [Primix Co., Ltd.], Ultra Turrax [IKA Co., Ltd.], Ebara Milder [Ebara Corporation], Cavitron (Eurotech Co., Ltd.) and Biomixer [Nippon Seiki Co., Ltd.] Manufactured] and the like.

The number of rotations when the isocyanate-terminated prepolymer (P) or an organic solvent solution thereof is subjected to dispersion treatment using the rotary dispersion mixer (A1) is preferably 10 to 30000 rpm, more preferably 20 to 30 rpm from the viewpoint of dispersion ability. It is 20,000 rpm, more preferably 30 to 10,000 rpm.

The main dispersion principle of the ultrasonic dispersion device (A2) is to apply energy to the processed material from the outside by the vibration of the driving unit to form fine particles for dispersion. Further, (A2) can be operated under normal pressure, reduced pressure or increased pressure.

As the ultrasonic dispersion device (A2), an ultrasonic dispersion device commercially available from Ikemoto Rika Kogyo Co., Ltd., Cosmo Bio Co., Ltd., Ginsen Co., Ltd. or the like can be used.

The frequency of dispersion treatment of the isocyanate-terminated prepolymer (P) or its organic solvent solution using the ultrasonic dispersion device (A2) is preferably 1 to 100 kHz, more preferably 3 to 10 from the viewpoint of dispersion ability. 60 kHz, particularly preferably 10 to 30 kHz.

The main dispersion principle of the kneading machine (A3) is to knead the processed material in the rotating part of (A3) to give energy to form fine particles and disperse them. Further, (A3) can be operated under normal pressure, reduced pressure or increased pressure.
As the kneading machine (A3), a twin-screw extruder [PCM-30 manufactured by Ikegai Co., Ltd.], a kneader [KRC kneader manufactured by Kurimoto Iron Works Co., Ltd.], a universal mixer [Hibismix manufactured by Primix Co., Ltd.] Etc.] and Plastomill [Labo Plastomill etc. manufactured by Toyo Seiki Seisakusho Co., Ltd.] and the like.

The number of rotations when the isocyanate-terminated prepolymer (P) or the organic solvent solution thereof is subjected to dispersion treatment using the kneading machine (A3) is preferably 1 to 1000 rpm, more preferably 3 to 500 rpm, particularly preferably 3 to 500 rpm, from the viewpoint of dispersion ability. It is preferably 10 to 200 rpm.

The weight ratio of the isocyanate-terminated prepolymer (P) or its organic solvent solution to water supplied to the dispersing device (A) is appropriately selected depending on the resin component content of the desired aqueous dispersion, but is preferably {( P) or its organic solvent solution}/water=10/2 to 10/100, and more preferably 10/5 to 10/50.

When dispersing with the dispersing device (A), if necessary, one or more additives selected from a pH adjusting agent, a viscosity adjusting agent, an antifoaming agent, a preservative, an anti-degrading agent, an antifreezing agent and the like are added. It can be added. Further, if necessary, solvent removal, concentration and dilution may be performed after the dispersion.

Examples of the pH adjuster include alkaline substances such as strong bases (alkali metals, etc.) and weak acids (acids with pKa exceeding 2.0, such as carbonic acid and phosphoric acid) (sodium bicarbonate, etc.) and acidic substances (acetic acid, etc.). Can be mentioned.

Examples of the viscosity modifier include thickeners such as inorganic viscosity modifiers (sodium silicate, bentonite, etc.), cellulose viscosity modifiers (Methylcellulose having Mn of 20,000 or more, carboxymethylcellulose, hydroxymethylcellulose, etc.), proteins. System viscosity modifiers (casein, casein soda, casein ammonium, etc.), acrylics (sodium polyacrylate having Mn of 20,000 or more and ammonium polyacrylate, etc.) and vinyl viscosity modifiers (Mn of 20,000 or more) Polyvinyl alcohol and the like).

Examples of the defoaming agent include long-chain alcohols (octyl alcohol, etc.), sorbitan derivatives (sorbitan monooleate, etc.), silicone oils (polymethylsiloxane, polyether-modified silicone, etc.) and the like.
Examples of the preservatives include organic nitrogen-sulfur compound-based preservatives and organic sulfur halide-based preservatives.

Examples of the deterioration inhibitors (UV absorbers and antioxidants) include hindered phenol-based, hindered amine-based, hydrazine-based, phosphorus-based, benzophenone-based and benzotriazole-based deterioration inhibitors and stabilizers.
Examples of the antifreezing agent include ethylene glycol and propylene glycol.

The content of the viscosity modifier, the defoaming agent, the preservative, the deterioration inhibitor and the antifreezing agent is preferably 5% by weight or less, and more preferably 3% by weight or less, based on the weight of the polyurethane resin aqueous dispersion. ..

The polyurethane resin aqueous dispersion (Q) of the present invention may further contain a crosslinking agent.
As the cross-linking agent, a carbodiimide cross-linking agent capable of reacting with an anionic group optionally added to the polyurethane resin (U) and a terminal hydroxyl group when a mono- or dialkanolamine is used as the terminal blocking agent (s). There is a blocked isocyanate or the like that can be reacted at a high temperature.

The device for reacting the chain extender (d) and the terminal blocking agent (s) after dispersing the isocyanate-terminated prepolymer (P) or the organic solvent solution thereof in the aqueous medium is not particularly limited, but the dispersing device (A ), a flask, a static mixer, and the like are preferably mixed and reacted.

The solid content concentration (content of components other than volatile components) of the polyurethane resin aqueous dispersion (Q) is preferably 20 to 65% by weight, more preferably 25 to 55% from the viewpoint of easy handling of the aqueous dispersion. % By weight. The solid content concentration was about 1 g of the aqueous dispersion, which was thinly spread on a Petri dish and precisely weighed, and then the weight after heating for 45 minutes at 130° C. using a circulation type constant temperature dryer was precisely weighed, and before heating. It can be obtained by calculating the ratio (percentage) of the residual weight after heating to the weight.

The pH of the polyurethane resin aqueous dispersion (Q) is preferably 2 to 12, and more preferably 4 to 10. The pH can be measured at 25° C. with pH Meter M-12 [manufactured by Horiba, Ltd.].

The viscosity of the polyurethane resin aqueous dispersion (Q) is preferably 10 to 100,000 mPa·s, more preferably 10 to 5,000 mPa·s. The viscosity can be measured under a constant temperature of 25° C. using a BL type viscometer.

The volume average particle diameter (Dv) of the particles containing the polyurethane resin (U) in the aqueous polyurethane resin dispersion (Q) is preferably 0.01 to 1 μm, more preferably 0.02 to 0.7 μm, and particularly preferably Is 0.03 to 0.4 μm. When (Dv) is 0.01 μm or more, the viscosity is appropriate and the handling property is good, and when it is 1 μm or less, the dispersion stability is good. The volume average particle diameter (Dv) is measured by a light scattering particle size distribution measuring device.

The volume average particle diameter (Dv) of the particles in (Q) can be adjusted by the ionic group in (U), the amount of the dispersant, the type of the disperser used in the dispersion step, and the operating conditions. Therefore, in order to bring the volume average particle diameter (Dv) of (Q) into the desired range, an apparatus selected from the below-mentioned rotary disperser, ultrasonic disperser, and kneader is used in the dispersion step. If necessary, the content of the ionic group introduced into (U) and the amount of the dispersant (h) added as necessary may be adjusted appropriately.

The polyurethane resin aqueous dispersion (Q) of the present invention can be suitably used as an easy-adhesion layer between a resin film and a polyester film as a member for a prism sheet used in a backlight unit of a liquid crystal display or the like. In this case, it is used in the form of a multilayer film having a dry film of (Q) on at least one side of a polyester film.

Examples of the polyester used for the polyester film as the member for the prism sheet include those obtained by polycondensing dicarboxylic acid and glycol. Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and adipine. Examples of the acid include sebacic acid, and examples of the glycol include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol and 1,6-hexane glycol. Among these, preferred is a polyester obtained by polycondensing terephthalic acid and ethylene glycol.

The polyester film as the member for the prism sheet, for example, polyester using a single-screw extruder and a cooling roll, to produce a non-stretched polyester film, the resulting non-stretched polyester film by a roll or tenter stretching machine It is preferably produced by a method of stretching in one direction and then stretching in a direction orthogonal to the stretching direction of the first stage.

As a method for producing a multilayer film having a dry film of the polyurethane resin aqueous dispersion (Q) of the present invention on at least one surface of a polyester film, in-line coating applied during the production process of the polyester film or polyester after production An off-line coating applied to the film is included. From the viewpoint of the adhesion of (Q) to the polyester film, production by in-line coating is preferable.
The thickness of the dried film (Q) is preferably 0.1 to 2 μm from the viewpoint of adhesion and blocking resistance.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. In the following, “part” means “part by weight” and “%” means “% by weight”.

<Example 1>
A simple pressure reactor equipped with a stirrer and a heating device contains 57.0 parts of Praxel 220 as the polyol (a), 31.3 parts of IPDI as the organic polyisocyanate (b), an ionic group and an active hydrogen atom. 2.3 parts of dimethylolpropionic acid as the compound (c), 3.3 parts of 1,4-butanediol as the chain extender (e2) and 40.2 parts of acetone as the organic solvent (1) were charged. A urethane reaction was carried out by stirring at 85° C. for 12 hours to produce a 70% organic solvent solution of the isocyanate-terminated prepolymer (P-1). The isocyanate group content of the isocyanate-terminated prepolymer (P-1) was 3.30%.
Then, a 70% organic solvent solution of the isocyanate-terminated prepolymer (P-1) was further diluted to 60% with 22.4 parts of acetone as the organic solvent (2), and then 1.6 parts of triethylamine as a neutralizing agent was added. , 105.9 parts of water [total value of 0.5 part of water as the chain extender (e1) and 105.4 parts of water as the aqueous medium] were added under stirring over 10 minutes (P-1 ) Is further dispersed, and 11.1 parts of a 50% aqueous solution of diethanolamine as an end-capping agent (s) and 36.9 parts of water are added, followed by chain extension reaction with water as a chain extender (e1) and termination. While carrying out the sealing reaction, the organic solvents (1) and (2) were distilled off under reduced pressure at 65° C. for 8 hours to obtain a polyurethane resin aqueous dispersion (Q- containing a polyurethane resin (U) and an aqueous medium. 1) was obtained.

<Examples 2 to 6 and Comparative Examples 1 to 6>
Polyurethane resin aqueous dispersions (Q-2) to (Q-6) and (Q'-1) to (Q'-in the same manner as in Example 1 except that the raw materials and the amounts used in Table 1 were changed. 6) was obtained. In Comparative Examples 1 to 4, the end capping reaction with the end capping agent (s) was not performed.

<Example 7>
In a simple pressure reactor equipped with a stirrer and a heating device, 57.0 parts of Praxel 220 as the polyol (a), 31.3 parts of IPDI as the organic polyisocyanate (b), and as the endcapping agent (s) 3.7 parts of n-butyl alcohol, 2.3 parts of dimethylolpropionic acid as a compound (c) containing an ionic group and an active hydrogen atom, 1,4-butanediol as a chain extender (e2) 3. 3 parts and 41.5 parts of acetone as the organic solvent (1) were charged and stirred at 85° C. for 12 hours to carry out a urethanization reaction to produce a 70% organic solvent solution of the isocyanate-terminated prepolymer (P-7). .. The isocyanate group content of the isocyanate terminated prepolymer (P-7) was 1.65%.
Then, a 70% organic solvent solution of the isocyanate-terminated prepolymer (P-7) was further diluted to 60% with 21.6 parts of acetone as the organic solvent (2), and then 1.6 parts of triethylamine as a neutralizing agent was added. , 106.2 parts of water [total value of 0.5 part of water as the chain extender (e1) and 105.7 parts of water as the aqueous medium] were added under stirring over 10 minutes (P-7). ) Is dispersed, and 39.3 parts of water is further added, and then the organic solvent (1) and (2) are added under reduced pressure at 65° C. for 8 hours while performing a chain extension reaction with water as a chain extender (e1). ) Was distilled off to obtain a polyurethane resin aqueous dispersion (Q-7) containing the polyurethane resin (U) and an aqueous medium.

The composition of raw materials described by trade names in Table 1 is as follows.
-Plaxel 220: Mn=2,000 polycaprolactone diol [manufactured by Daicel Corporation]
-Ethanacol UH-200: poly(1,6-hexanediol)carbonate diol with Mn=2,000 [manufactured by Ube Industries, Ltd.]
-Nipporan 980R: polyhexamethylene carbonate diol with Mn=2,000 [manufactured by Nippon Polyurethane Industry Co., Ltd.]
PTMG2000: poly(oxytetramethylene) glycol with Mn=2,000 [manufactured by Mitsubishi Chemical Corporation]
-Kuraray polyol P-2010: poly 3-methyl-pentamethylene adipate with Mn=2,000 [manufactured by Kuraray Co., Ltd.]

Adhesion and heat resistance of the polyurethane resin aqueous dispersions (Q-1) to (Q-7) and (Q'-1) to (Q'-6) obtained in Examples 1 to 7 and Comparative Examples 1 to 6. Table 1 shows the results of evaluation of yellowing by the following evaluation method. The isocyanate group content of the isocyanate group-terminated prepolymer (P) during the production of each polyurethane resin aqueous dispersion (Q) and the moles of the terminal blocking agent (s) relative to the number of moles of the isocyanate groups contained in the prepolymer (P). The number ratios are also shown in Table 1.

<Adhesion>
A commercially available PET film [Lumirror L-100S, manufactured by Toray Industries, Inc.] was coated with a polyurethane resin aqueous dispersion having a solid content of 20% diluted with water to a thickness of 7 μm, dried at 230° C. for 3 minutes, and coated. A membrane was prepared. FineCure BCP-34 [Acrylourethane photocurable resin manufactured by Sanyo Chemical Industry Co., Ltd.] was applied to the surface of the coating film at a thickness of 20 μm and cured by irradiating with ultraviolet rays at a condition of 500 mJ/cm ² . The cured film of the obtained multilayer film and the dried film of the polyurethane resin aqueous dispersion are cut with a cutter knife to a width of 1 mm so that 100 (10×10) masses can be formed according to JIS K5600-5-6. Then, a peeling test was performed using a transparent pressure-sensitive adhesive tape to evaluate the adhesiveness. The evaluation result was expressed by "the squares remaining on the substrate after the test/100".

<Heat resistant yellowing>
Pour 10 parts of the polyurethane resin aqueous dispersion into a polypropylene mold having a length of 10 cm, a width of 20 cm, and a depth of 1 cm so that the film thickness after drying becomes 200 μm, and dry at room temperature for 12 hours, and then use an air-circulation dryer. A film was prepared by heating and drying at 105° C. for 3 hours. The obtained film was cut into 5 cm square pieces, placed on a glass plate (length 20 cm×width 20 cm×thickness 0.5 cm), placed in a circulating air drier, and heated at 140° C. for 4 hours. After heating at ℃ for 4 hours, further heated at 250 ℃ for 15 minutes to obtain a film (2). For the film before heating and the films (1) and (2) after heating, the yellowness (YI) was measured using "Spectro Photometer SD5000" manufactured by Nippon Denshoku Industries Co., Ltd. to obtain the film (1) or (2). The yellowness (YI) of the film before heating was subtracted from the yellowness (YI) of ( ₁ ) to calculate the ΔYI value, and the heat-resistant yellowing was evaluated according to the following criteria.
<Evaluation criteria>
◯: ΔYI value before and after heating is less than 30 Δ: ΔYI value before and after heating is 30 or more and less than 60 ×: ΔYI value before and after heating is 60 or more

The polyurethane resin aqueous dispersion (Q) of the present invention can form an adhesive layer having excellent adhesiveness between a base material and a functional layer and heat-resistant yellowing, and thus is used in a backlight unit of a liquid crystal display, etc. It can be suitably used for an easily adhesive layer of a polyester film and a resin prism as an optical member for use. Further, by utilizing this easy adhesiveness, it can be used as a resin for a primer layer of an acrylic resin for paint.

Claims (5)

Isocyanate group-terminated prepolymer (P) containing a polymer polyol (a) having a number average molecular weight of 500 or more and an organic polyisocyanate (b) as essential constituent monomers, a chain extender (e), and a terminal blocking agent (s) A polyurethane resin (U) in which the ratio of the number of moles of the terminal blocking agent (s) to the number of moles of the isocyanate group of the prepolymer (P) is 0.25 to 0.75. ) And an aqueous medium, a polyurethane resin aqueous dispersion (Q). The polymer polyol (a) is at least one polyester polyol selected from the group consisting of polycaprolactone polyol (a11), polycarbonate polyol (a12), and polyester polyol (a13) having a carboxylic acid ester group and a carbonic acid ester group. The polyurethane resin aqueous dispersion according to claim 1. The polyurethane resin aqueous dispersion according to claim 1, wherein the isocyanate group-terminated prepolymer (P) has an isocyanate group content of 2 to 4% by weight. 4. The endcapping agent (s) is at least one endcapping agent selected from the group consisting of monohydric alcohols having 1 to 10 carbon atoms and monoamines having 1 to 10 carbon atoms. An aqueous dispersion of the polyurethane resin as described above. A multilayer film having a dry film of the polyurethane resin aqueous dispersion (Q) according to any one of claims 1 to 4 on at least one surface of the polyester film.