JP2000198962A - Aqueous coating agent for decorative laminate or wallpaper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous coating agent capable of forming a coating film excellent in resistances to abrasion and blocking by incorporating a water- soluble or water-dispersible polyurethane resin containing anionic or anion- forming groups in the molecule and having specified solubility parameter and glass transition temperature into the same. SOLUTION: This coating agent contains a water-soluble or water-dispersible polyurethane resin containing 0.1-10 mmol/g of anionic or anion-forming groups (e.g. carboxyl groups) in the molecule and having a solubility parameter of 11-12, a glass transition temperature of 40-150 deg.C, a sum of concentrations of urethane groups and urea groups of 2-8 mmol/g, and a wt, average mol.wt. of 3, 000-200,000 and a crosslinker in an amount lower than 50 mass %. The agent has a resin content of 20-60 mass % and a viscosity (at 40 mass % concentration) of 100-2,000 mPa.s/25 deg.C. A water-soluble or water-dispersible polyepoxy compound (e.g. a polyglycidyl ether of a polyhydric alcohol) is used as the crosslinker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous coating agent for decorative boards or wallpaper. More specifically, it has excellent abrasion resistance, chemical resistance, stain resistance, blocking resistance, etc., and is especially used for decorative paper and resin decorative sheets (vinyl chloride resin, acrylic resin, polystyrene, polypropylene, The present invention relates to an aqueous coating agent suitable for a top coat agent for a decorative sheet made of a resin such as polyester.

[0002]

2. Description of the Related Art Conventionally, a solvent-based resin has been used as a top coating agent for decorative paper or a resin decorative sheet, but recently, environmental problems, resource saving, occupational safety, and fire. In view of the above, there is a strong demand for a water-based coating agent which minimizes the use of an organic solvent. As the aqueous coating agent, a coating film having a high surface hardness is required, and an acrylic resin-based aqueous dispersion has been proposed (for example, JP-A-9-15809).
No. 8). However, when an acrylic resin-based water-based coating agent is used as the top coat agent, there is a problem that abrasion resistance and chemical resistance are inferior to solvent-based resins. As a solution to these problems, a solution made of an aqueous urethane resin having a specific structure has been proposed (JP-A-9-235460).

[0003]

However, the above-mentioned compounds are excellent in abrasion resistance and chemical resistance, but are not always satisfactory in stain resistance and blocking resistance.

[0004]

Means for Solving the Problems The present inventors have intensively studied an aqueous coating agent for a decorative plate or a wallpaper for forming a coating film having excellent abrasion resistance, chemical resistance, stain resistance, blocking resistance and the like. As a result, the present invention has been achieved. That is, the present invention has an anion group or an anion-forming group in a molecule and has a solubility parameter (SP) of 11 to 12.
Value) and a water-soluble or water-dispersible polyurethane resin (A) having a glass transition temperature of 40 to 150 ° C., and an aqueous coating agent for decorative boards or wallpaper; Decorative paper or resin decorative sheet used for a decorative board or wallpaper used as a material.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The water-soluble or water-dispersible polyurethane resin (A) in the present invention includes, for example, an organic polyisocyanate (a) and a compound (b) having two or more active hydrogen-containing groups, Compound (c) having an active hydrogen-containing group and an anionic group or an anion-forming group in the molecule and, if necessary, a polymerization terminator (d),
The equivalent ratio of isocyanate group / active hydrogen-containing group is usually 0.1.
The reaction is carried out at 5 to 1.7, preferably 0.7 to 1.5 to form a urethane prepolymer. If the prepolymer has an anionic group, it is neutralized with a base to form an anionic group. Dissolved or dispersed in water, if necessary (if the prepolymer contains isocyanate groups)
Further, those obtained by a chain extension reaction with a chain extender (e) may be mentioned.

[0006] As the organic polyisocyanate (a) used in the present invention, those conventionally used in the production of polyurethane can be used. Such polyisocyanates include aromatic polyisocyanates having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same applies hereinafter), aliphatic polyisocyanates having 2 to 18 carbon atoms, and 4 to 15 carbon atoms.
Alicyclic polyisocyanates, araliphatic polyisocyanates having 8 to 15 carbon atoms and modified products of these polyisocyanates (urethane group, carbodiimide group, allophanate group, urea group, buret group, uretdione group, uretoimine group, isocyanate) Nurate group, oxazolidone group-containing modified product) and a mixture of two or more of these.

Specific examples of the aromatic diisocyanate include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'- 4,4 '
-Diphenylmethane diisocyanate (MDI), 4,
4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, crude M
DI [crude diaminophenylmethane [condensation product of formaldehyde with an aromatic amine (aniline) or a mixture thereof; diaminodiphenylmethane and a small amount (for example, 5
~ 20% by weight) of a triamine or higher polyamine)
Phosgenated product: polyallyl polyisocyanate (PA
PI)], 1,5-naphthylene diisocyanate, 4,
4 ', 4 "-triphenylmethane triisocyanate,
m- and p-isocyanatophenylsulfonyl isocyanate;

Specific examples of the aliphatic polyisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (H
DI), dodecamethylene diisocyanate, 1,6,1
1-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate And aliphatic polyisocyanates such as 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

Specific examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate,
Methylcyclohexylene diisocyanate (hydrogenated TD
I), bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- and / or 2,6-norbornane diisocyanate.

Specific examples of the araliphatic polyisocyanate include m- or p-xylylene diisocyanate (XDI) and α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI).

The modified polyisocyanate includes modified MDI (urethane-modified MDI, carbodiimide-modified MDI, trihydrocarbyl phosphate-modified MD).
I), urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI, isocyanurate-modified IP
Modified polyisocyanates such as DI and mixtures of two or more thereof are included. The urethane-modified polyisocyanate [excess polyisocyanate (TDI, MD
I) or the like, and a free isocyanate-containing prepolymer obtained by reacting a polyol with a polyol having an equivalent weight of 30 to 200, for example, a glycol such as ethylene glycol, propylene glycol, diethylene glycol or dipropylene glycol; Triols such as methylolpropane and glycerin; highly functional polyols such as pentaerythritol and sorbitol; and alkylene oxide (ethylene oxide and / or propylene oxide) adducts thereof.

Among these, preferred are aliphatic diisocyanates and alicyclic diisocyanates, and particularly preferred are HDI, IPDI and hydrogenated MDI.

As the compound (b) having two or more active hydrogen-containing groups used in the present invention, the high molecular polyol (b1) having a number average molecular weight of 300 to 5,000, preferably 500 to 3,000, A low molecular weight active hydrogen-containing compound (b2) having an average molecular weight of less than 300;
Mixtures of more than one species are included.

As the polymer polyol (b1), for example, polyether polyol, polyester polyol,
Examples thereof include polydiene polyol or a hydrogenated product thereof and a mixture of two or more thereof.

The polyether polyols include low molecular weight polyols having 2 to 20 carbon atoms [dihydric alcohols such as ethylene glycol, propylene glycol,
4-butanediol; bisphenols (bisphenol A, bisphenol S, bisphenol F, etc.);
Starting from a polyhydric alcohol such as glycerin or trimethylolpropane, alkylene oxide [alkylene oxide having 2 to 4 carbon atoms such as ethylene oxide (EO), propylene oxide (PO), 1,2
, 1,3- or 2,3-butylene oxide, tetrahydrofuran, etc.], and addition polymerization or addition copolymerization (block and / or random). Specific examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polyoxyethyleneoxypropylene (block or random) glycol, polyoxytetramethylene glycol, polyoxytetramethyleneoxyethylene (block or random) glycol, and ethylene oxide of bisphenol A. And / or propylene oxide adducts and mixtures of two or more thereof.

As the polyester polyol, for example, at least one of the low-molecular polyols exemplified as the starting materials for the polyether polyol, and a dicarboxylic acid [aliphatic dicarboxylic acid having 2 to 20 carbon atoms (for example, succinic acid,
Adipic acid, sebacic acid, etc.), aromatic dicarboxylic acids having 6 to 20 carbon atoms (eg, terephthalic acid, isophthalic acid, etc.), and ester-forming derivatives of these dicarboxylic acids (acid anhydrides, lower alkyl esters, etc.)] Condensed polyester polyol obtained by reacting with one or more [polyethylene adipate polyol, polybutylene adipate polyol, polyethylene butylene adipate polyol, etc.]; a lactone having 3 to 12 carbon atoms (ε-
Polylactone polyol (polycaprolactone polyol, polybutyrolactone polyol, polyvalerolactone polyol, etc.) obtained by ring-opening polymerization of caprolactone, γ-butyrolactone, γ-valerolactone, etc .; Ethylene carbonate, dimethyl carbonate, etc.)
(For example, polybutylene carbonate diol, polyhexamethylene carbonate diol, etc.) and a mixture of two or more thereof.

Examples of the polydiene polyol or its hydrogenated product include polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol,
And hydrogenated polyisoprene polyol.

The low molecular active hydrogen compound (b2) includes
For example, low molecular weight polyols exemplified as the starting materials for the polyether polyols, alkylene oxide (EO and / or PO) adducts (with a molecular weight of less than 300); water; polyamines [aliphatic diamines having 2 to 20 carbon atoms (eg, ethylenediamine; , Hexamethylenediamine, etc.), an alicyclic diamine having 4 to 20 carbon atoms (e.g., isophoronediamine, 4,4'-diaminodicyclohexylmethane, etc.), and an aromatic diamine having 6 to 20 carbon atoms (e.g., 4,4'-diamino Diphenylmethane, diaminotoluene, etc.), araliphatic diamines having 8 to 20 carbon atoms (eg, xylylenediamine), etc .; hydrazine or derivatives thereof [dibasic dihydrazide (eg, adipic dihydrazide, etc.)], and two or more thereof. And mixtures thereof.

Preferred among these are polyether diols, polyester diols, polycarbonate diols, and combinations of at least one of these with a low molecular weight diol.

As the compound (c) having an active hydrogen-containing group and an anionic group or an anion-forming group in the molecule, for example, a compound having a carboxyl group and a hydroxyl group (eg, lactic acid, dimethylolpropionic acid, dimethylolbutyric acid) ), A compound having a sulfonic acid group and an amino group or a hydroxyl group [eg, aminoethylsulfonic acid, 3- (2,3-dihydroxypropoxy) propanesulfonic acid, etc.], a compound having a phosphoric acid group [bis- (2 -Hydroxyethyl) phosphate], and neutralized products thereof with a volatile base (eg, ammonia, trimethylamine, triethylamine, etc.) and / or a non-volatile base (eg, sodium hydroxide, potassium hydroxide, etc.). Among these, preferred are compounds having a carboxyl group and a hydroxyl group and salts of volatile bases thereof, and particularly preferred are dimethylolpropionic acid and its ammonium salt or triethylamine salt.

Examples of the polymerization terminator (d) include aliphatic monohydric alcohols having 1 to 20 carbon atoms (such as methanol, ethanol, butanol and stearyl alcohol), and monoamines (mono- or dialkylamines having 1 to 20 carbon atoms). For example, diethylamine, butylamine, dibutylamine, octylamine, stearylamine and the like; alkanolamines having 2 to 4 carbon atoms, such as monoethanolamine, diethanolamine, diisopropanolamine and the like can be mentioned.

As the chain extender (e), the low molecular polyol exemplified as the low molecular active hydrogen compound (b2),
Examples include water, aliphatic diamines, alicyclic diamines, aromatic diamines, and hydrazine or derivatives thereof. Preferred among these are water, aliphatic diamines, alicyclic diamines, and hydrazine or derivatives thereof.

As a method for producing the water-soluble or water-dispersible polyurethane resin (A), for example, organic solvents containing no active hydrogen in the molecule [ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (acetic acid)] Ethyl, butyl acetate, ethyl cellosolve acetate, etc.), ethers (dioxane, tetrahydrofuran, etc.), hydrocarbons (n-hexane, n-heptane, cyclohexane, tetralin, toluene, xylene, etc.), chlorinated hydrocarbons (dichloroethane) , Trichloroethane, trichloroethylene, perchloroethylene, etc.), amides (dimethylformamide, dimethylacetamide, etc.), N-methylpyrrolidone, etc.] in the presence or absence of the above (a), (b), (c) and (D) if necessary When the equivalent ratio (isocyanate group / active hydrogen group) of the cyanate group to the active hydrogen-containing group (excluding the carboxyl group) is usually 0.5 to 1.7, preferably 0.7 to 1.5, one shot 20 ° C. to 150 ° C., preferably 60 ° C. to 1
The mixture is reacted at 10 ° C. for 2 to 10 hours to form a urethane prepolymer, and then the prepolymer is neutralized with a base (for example, ammonia, triethylamine, sodium hydroxide, potassium hydroxide, or the like), or while neutralizing, usually 10%. C. to 60.degree. C., preferably 20.degree. C. to 40.degree. C., dissolved or dispersed in water, and if necessary (if the prepolymer contains isocyanate groups), further mix (e) to eliminate the isocyanate groups. A method in which a chain extension reaction is performed until the organic solvent evaporates, and the organic solvent is distilled off if necessary.

In the urethanization reaction, catalysts used in ordinary urethanization reactions, such as amine catalysts (triethylamine, N-ethylmorpholine, triethylenediamine, etc.), tin catalysts (dibutyltin Dilaurate, dioctyltin dilaurate, tin octylate, etc.), and titanium-based catalysts (tetrabutyl titanate, etc.). The amount of the catalyst used is usually 0.1% by weight or less based on the weight of the polyurethane resin.

Preferred as the polyurethane resin (A) thus obtained is that the content of the anion group or the anion-forming group in the (A) is usually 0.1 to 10 mmol / g per resin solid content, Preferably 0.2 to
8 mmol / g, more preferably 0.3 to 6 mmol / g
g. When the content of the anionic group or the anion-forming group is less than 0.1 mmol / g, the solvent resistance of the coating film is insufficient, and when it exceeds 10 mmol / g, the water resistance of the coating film tends to decrease.

The (A) has a number average molecular weight of 3,000 to 2
00,000 or more, preferably 5,000 to
150,000. If the number average molecular weight is less than 3,000, the resulting coating film has insufficient solvent resistance, which is not preferable.

The solubility parameter (S) of (A)
P value) is usually 11 to 12, preferably 11.2 to 11.
8 If the SP value is less than 11, the abrasion resistance and stain resistance are reduced, and if it exceeds 12, the water resistance tends to be reduced. The SP value is, for example, POLYMER ENGINEERING AND SCIE
It can be obtained by the method proposed by RFFEDORS described in NCE, 1974, VOL14, NO.

The glass transition temperature measured by the differential scanning calorimetry (DSC) method (A) is usually 40 to 150 ° C., preferably 50 to 140 ° C., and more preferably 60 to 130 ° C.
° C. When the glass transition temperature is less than 40 ° C, the stain resistance and blocking resistance of the coating film are insufficient, and when the glass transition temperature exceeds 150 ° C, the film-forming property is poor, so that it may be difficult to form a good coating film.

The urethane group (-NHCOO) in the above (A)
-) And the urea group (-NHCONH-) have a total concentration of usually 2 to 8 mmol / g, preferably 3 to 7 mmol.
/ G. When the total concentration of the urethane group and the urea group is 2
If the amount is less than mmol / g, the abrasion resistance and blocking resistance of the coating film decrease, and if it exceeds 8 mmol / g, the film-forming property tends to decrease.

The coating agent of the present invention may contain, if necessary, two or more functional groups capable of reacting with a carboxyl group or a hydroxyl group in the resin (A) together with the resin (A) in order to form a coating film having better durability. The water-soluble or water-dispersible crosslinking agent (B) can be used in combination.

As the crosslinking agent (B), a water-soluble or water-dispersible polyepoxy compound (B1) [for example, ethylene glycol or polyethylene glycol (polymerization degree: 2
10 to 10) diglycidyl ether (molecular weight: 600 or less); glycerin, polyglycerin (degree of polymerization: 2 to 8);
Polyglycidyl ethers of polyhydric alcohols having 3 to 8 or more valences such as trimethylolpropane and sorbitol (molecular weight of 1,500 or less); those obtained by adding alkylene oxide (2 to 3 carbon atoms) to the above polyhydric alcohols ( Water-soluble or water-dispersible polyglycidyl ethers having an addition mole number of 1 to 10) (molecular weight of 2,000 or less; aqueous emulsions of bisphenols or novolak polyglycidyl ethers (molecular weight of 1,000 or less)] Water-soluble or water-dispersible aminoplast (B2) [for example, a urea or melamine derivative containing two or more (alkoxy having 1 to 4 carbon atoms) methylol groups (molecular weight of 500 or less)], water-soluble or water-dispersible Or aqueous polyisocyanate compound (B3) [for example, if IPDI Polyisocyanates aqueous emulsion blocked and 3 weight products of HDI and the like methyl ethyl ketoxime or ε- caprolactam; IP
A water-dispersible compound (having a molecular weight of 1,000 or less) in which a hydrophilic group such as a polyoxyethylene group is introduced into a trimer of DI or HDI or the like, a water-soluble or water-dispersible oxazoline compound (B4) [for example, Oxazoline group-containing polystyrene (molecular weight 300 to 10,000), oxazoline group-containing acrylonitrile styrene copolymer (molecular weight 3
00-10,000), bis (4,4'-ethyleneiminophenyl) methane and the like. Among these, preferred are (B1), more preferred are polyglycidyl ethers of polyhydric alcohols having 3 to 8 or more valences, and particularly preferred are polyglycerin (degree of polymerization 2 to 5) polyglycidyl ether. It is.

When (B) is used in combination, the amount used is usually not more than 50% by mass, preferably 3 to 45% by mass, based on the total mass of (A) and (B) as solids. Preferably it is 5 to 40% by mass. When the proportion of (B) is within the above range, a coating film having sufficient surface strength and excellent abrasion resistance, solvent resistance, chemical resistance and stain resistance when used as a top coat can be obtained. Can be The (B) is
It may be previously mixed with the coating agent comprising (A), or may be mixed at the time of use.

The aqueous coating agent of the present invention may further contain, if necessary, an aqueous resin other than (A), a release agent, a dye, a pigment, a stabilizer, a dispersant, a surfactant, an antifoaming agent, a preservative, Additives such as anti-freezing agents, thickeners and the like can be added.
Specific examples of these are as follows. Aqueous resin: water-soluble or water-dispersible acrylic, styrene / maleic acid copolymer, vinyl acetate, vinyl chloride or nonionic urethane resin, SBR or NBR
Aqueous resin such as latex. Release agents: Release agents such as silicone, fluorine, and wax. Dyes: Dyes such as direct dyes, reactive dyes, and metal complex dyes. Pigments: pigments such as titanium oxide, carbon black, and organic pigments. Stabilizers: hindered phenols, hydrazines, benzophenones, benzotriazoles, oxalic acid anilides, hindered amines, etc. Dispersant: a stabilizer such as a polyacrylic acid-based dispersant. Surfactant: a nonionic surfactant such as an ethylene oxide adduct of nonylphenol. Antifoaming agents: Antifoaming agents of silicone type, mineral oil type, alcohol type, etc. Preservatives: Preservatives such as organic nitrogen sulfur compounds and organic sulfur halogen compounds. Antifreeze: ethylene glycol, propylene glycol, and the like. Thickeners: cellulose derivatives, starch derivatives, polyvinyl alcohol, etc.

The concentration of the resin component of the aqueous coating agent of the present invention is usually 20 to 60% by mass, and the content of (A) in the resin component is at least 50% by mass, preferably 65% by mass.
That is all. The viscosity at a resin concentration of 40% by mass is usually 100 to 2,000 mPa · s / 25 ° C.

Paper, various plastics (vinyl chloride resin,
Acrylic resin, polystyrene, polypropylene, polyester, etc.) sheet, metal, wood, etc.
Particularly preferred are paper and plastic sheets having a base pattern and colors.

The method for applying the coating agent of the present invention to a substrate is not particularly limited, and the coating is carried out using a known coating device, for example, a roll coater, a reverse roll coater, a gravure coater, a knife coater or the like. The coating amount can be appropriately selected according to the purpose, but is usually ^{2 to 20} g / m ² , preferably 3 to 10 g / m ^{2 in} dry film thickness.
It is. The coating agent is applied to a substrate, dried by heating, and then cured at 50 to 80 ° C. for 1 to 3 days (especially when a crosslinking agent is used together), so that the coating film has sufficient coating properties and durability. To form

The water-based coating agent of the present invention gives a coating film having excellent abrasion resistance, chemical resistance, stain resistance and durability. Can be suitably used as a top coat agent. In addition, it can be used advantageously as a top coat agent for various interiors. As the base to which the top coat agent is applied, for example, papers on which a decorative pattern is printed, the printing ink surface or the base of the plastic sheet on which the decorative pattern is printed, the base of the plastic sheet colored with a pigment, or the like Is mentioned.

[0038]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the following, "parts" indicates parts by mass and "%" indicates mass%.

Production Example 1 162 parts of an ethylene oxide adduct of bisphenol A having a number average molecular weight of 320, 218 parts of hexamethylene diisocyanate and 67 parts of dimethylolpropionic acid were added to 300 L of acetone in a 2 L autoclave, and dried at 80 ° C. in a dry nitrogen atmosphere. For 7 hours to obtain an acetone solution of an NCO-terminated urethane prepolymer having an NCO% content of 3.4%. The obtained acetone solution was cooled to 30 ° C., and 40 parts of triethylamine was added. Next, 800 parts of water is added to the acetone solution, acetone is removed at 50 to 60 ° C. under reduced pressure, solid content 40%, viscosity 850 mPa · s / 25 ° C.
Thus, an aqueous urethane resin dispersion (I) was obtained. The glass transition temperature (Tg) of this urethane resin measured by a differential scanning calorimeter (DSC) was 50 ° C., the number average molecular weight (Mn) measured by GPC was 20,000, and the total content of urethane groups and urea groups was 5.15 mmol / g.

Production Example 2 162 parts of an ethylene oxide adduct of bisphenol A having a number average molecular weight of 320, 289 parts of isophorone diisocyanate and 67 parts of dimethylolpropionic acid were added to 300 parts of acetone in a 2 L autoclave, and dried at 80 ° C. under a nitrogen atmosphere. After reacting for 7 hours, the NCO% content was 3.1.
% NCO-terminated urethane prepolymer in acetone. The obtained acetone solution was cooled to 30 ° C., and 40 parts of triethylamine was added. Next, 800 parts of water was added to the acetone solution, and acetone was removed at 50 to 60 ° C under reduced pressure to obtain an aqueous urethane resin dispersion (II) having a solid content of 40% and a viscosity of 1100 mPa · s / 25 ° C. The Tg of this urethane resin was 95 ° C., the Mn was 15,000, and the total content of urethane groups and urea groups was 4.46 mmol / g.

Production Example 3 In a 2 L autoclave, 162 parts of an ethylene oxide adduct of bisphenol A having a number average molecular weight of 320, 340 parts of dicyclohexylmethane-4,4'-diisocyanate and 67 parts of dimethylolpropionic acid were added to 30 parts of acetone.
0 parts, and reacted at 80 ° C. for 7 hours under a dry nitrogen atmosphere to obtain an acetone solution of an NCO-terminated urethane prepolymer having an NCO% content of 2.9%. The obtained acetone solution was cooled to 30 ° C., and 40 parts of triethylamine was added.
Next, 900 parts of water is added to the acetone solution,
Acetone is removed at 60 ° C., solid content 40%, viscosity 790
mPa · s / 25 ° C. aqueous urethane resin dispersion (II
I) was obtained. The Tg of this urethane resin is 102 ° C., Mn
Was 15,000, and the total content of urethane groups and urea groups was 4.05 mmol / g.

Production Example 4 In a 2 L autoclave, 120 parts of an ethylene oxide adduct of bisphenol A having a number average molecular weight of 320 and polybutylene adipate diol 42 having a number average molecular weight of 1,000 were added.
340 parts of dicyclohexylmethane-4,4'-diisocyanate and 67 parts of dimethylolpropionic acid were added to 300 parts of acetone, and reacted at 80 ° C. for 7 hours in a dry nitrogen atmosphere to obtain an NCO% content of 4.0%. An acetone solution of the NCO-terminated urethane prepolymer was obtained. The obtained acetone solution is cooled to 30 ° C. and triethylamine 40
Parts were added. Then add 900 parts of water to the acetone solution,
The acetone is removed at 50 to 60 ° C. under reduced pressure to obtain a solid content of 40%.
%, And an aqueous urethane resin dispersion (IV) having a viscosity of 480 mPa · s / 25 ° C. was obtained. The Tg of this urethane resin is 60
C., Mn was 13,000, and the total content of urethane groups and urea groups was 3.89 mmol / g.

Comparative Production Example 1 200 parts of isopropanol were charged and the temperature was raised to 80 ° C.
In an L flask, 20 parts of styrene and methyl methacrylate 1
100 parts of a toluene solution in which 200 parts of a mixed monomer of 50 parts and 30 parts of acrylic acid and 10 parts of azobisisobutyrotrile were dissolved was added dropwise over 3 hours, and a polymerization reaction was further performed at 80 ° C. for 1 hour. The obtained polymer solution was cooled to 30 ° C., and neutralized by adding 20 parts of 35% aqueous ammonia.
0 parts were added, isopropanol and toluene were removed under reduced pressure, solid content was 30%, viscosity was 900 mPa · s / 25 ° C.
Thus, an aqueous acrylic resin (V) was obtained. The acrylic resin had a Tg of 98 ° C. and a Mn of 8,000.

Comparative Production Example 2 To a 2 L autoclave, 500 parts of polybutylene adipate diol having a number average molecular weight of 2,000, 109 parts of hexamethylene diisocyanate and 34 parts of dimethylolpropionic acid were added to 300 parts of acetone. After reacting for 7 hours, an acetone solution of an NCO-terminated urethane prepolymer having an NCO% content of 1.3% was obtained. The obtained acetone solution was cooled to 30 ° C., and 20 parts of triethylamine was added. Next, 1000 parts of water was added to the acetone solution, and acetone was removed at 50 to 60 ° C. under reduced pressure to obtain an aqueous urethane resin dispersion (VI) having a solid content of 40% and a viscosity of 1000 mPa · s / 25 ° C. The Tg of the urethane resin was −20 ° C., the Mn was 10,000, and the total content of urethane groups and urea groups was 1.79 mmol / g.

Examples 1-4, Comparative Examples 1-2 Each aqueous resin was mixed with a crosslinking agent and water according to the formulation shown in Table 1 to prepare a coating solution for coating. Each coating solution was coated on a high quality paper using a bar coater to a thickness of 20 μm (wet thickness), dried with hot air at 120 ° C. for 1 minute, and then dried at 60 ° C.
For 3 days. The coated paper was bonded to a particle board with a vinyl acetate adhesive, and pressure-bonded with a pressure press at 10 kgf / cm 2 at 150 ° C. to prepare a test sample, and the performance was evaluated by the following test method.
Table 2 shows the results.

[0046]

[Table 1] * 1: Water-soluble polyepoxy compound, polyglycidyl ether of tetraglycerin [manufactured by Nagase Kasei Co., Ltd .; Denacol EX-521] * 2: Nonionic surfactant, 10 mol of nonylphenol ethylene oxide adduct [Sanyo Chemical Industries, Ltd.] Manufactured by Nonipol 100]

<Test Method and Evaluation> (1) Abrasion resistance test: The surface of the test piece was tested using a wear tester [manufactured by Yasuda Seiki Co., Ltd.] using a wear wheel CS17 and a load of 50.
After 100 revolutions under the condition of 0 g, the state of the surface was evaluated. Evaluation criteria ○: 80% or more remains △: 80 to 50% remains ×; remainder less than 50% (2) Chemical resistance test: 5% aqueous sodium hydroxide solution, 5% aqueous acetic acid solution and lacquer thinner were applied to the surface of the test piece. Each was dropped and covered with a watch glass. Six hours later, the watch glass of the coating was removed and wiped off, and the surface condition after standing at room temperature for 24 hours was observed. Evaluation criteria ；: no change ；: partial blistering ×: full blistering (3) Stain resistance test: A 1 cm wide line was drawn on the surface of the test piece with red crayon, blue ink and magic ink, and after leaving for 4 hours, After wiping with ethanol, the surface was observed. Evaluation criteria ○: No stain △: Slight stain ×; Stain remains (4) Blocking resistance test: 60 ° C. with the coated surface of the coated paper before curing and curing pressed at 2 kg / cm 2
Left in the oven. It was taken out after 24 hours, the coated surface and the coated surface were peeled off, and the state of blocking was observed. Evaluation criteria ○: easily peeled off △: resisted but peeled off ×: not peeled off

[0048]

[Table 2]

[0049]

The coating agent using the aqueous dispersion of the present invention not only meets the requirements for desolvation, but also has the problems of abrasion resistance, chemical resistance, stain resistance, and resistance to the problems of conventional aqueous coating agents. Form a coating film having good blocking properties.
Due to the above effects, the water-based coating agent of the present invention is extremely useful especially as a topcoat agent for decorative paper or resin decorative sheet used for decorative boards or wallpaper.

Continued on front page F-term (reference) 4F100 AK51A AT00B BA02 BA10A BA10B CA02A CA02H CC01A DG10B GB08 HB00B JA05A JB01 JB06A JB09A JK09 JL05 JL06 YY00A 4J038 DB002 DG001 KA03 MA08 MA09 MA10 MA13 PA07

Claims (6)

[Claims] An anion group or an anion-forming group in a molecule having a solubility parameter of 11 to 12 (SP
Value) and a water-soluble or water-dispersible polyurethane resin (A) having a glass transition temperature of 40 to 150 ° C. 2. The coating agent according to claim 1, wherein the anion group or the anion-forming group is a carboxylic acid (salt) group. 3. The urethane group (-NHCOO) in (A)
-) And the urea group (-NHCONH-) have a total concentration of 2
The coating agent according to claim 1, wherein the amount is from 8 to 8 mmol / g. 4. The coating agent according to claim 1, further comprising a water-soluble or water-dispersible crosslinking agent (B). 5. The coating agent according to claim 4, wherein (B) is a water-soluble polyepoxy compound. 6. A decorative paper or resin decorative sheet used for a decorative board or wallpaper using the coating agent according to claim 1 as a top coat agent.