JP2511774B2 - Method for producing aqueous dispersion of polyurethane resin - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aqueous dispersion of a high molecular weight polyurethane resin neutralized with a primary and / or secondary monoamine.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an aqueous dispersion of a polyurethane resin, a urethane prepolymer containing a terminal NCO group having an anionic group such as a carboxyl group in the molecule is neutralized with a tertiary amine, and then emulsion extension is carried out. (For example, Japanese Patent Publication No. 53-38760, Japanese Patent Publication No. 63-8141), or a terminal NCO group-containing urethane prepolymer is reacted with a chain extender and / or a polymerization terminator to form a terminal NCO group. A method is known in which, after blocking, it is neutralized with a primary and / or secondary monoamine and then emulsified to produce (Japanese Patent Application No. 3-327393).

[0003]

However, the above method has an advantage that a resin having a high molecular weight can be obtained and a resin having high resin properties can be obtained, but it is water-soluble in thermosetting paints and adhesives. When an amino resin is used as a curing agent and heat-cured in the presence of an acidic catalyst, there are problems that the activity of the acidic catalyst is blocked by the tertiary amine and it is difficult to cure at low temperature, and further that it takes time to cure even at high temperature. there were. The water-based polyurethane resin dispersion obtained by the other method does not cause the above-mentioned curing inhibition, but has a drawback that it is difficult to obtain a high molecular weight and it is difficult to obtain sufficient resin physical properties.

[0004]

The present inventors have arrived at the present invention as a result of intensive studies to solve these problems. That is, the present invention provides a polyurethane resin aqueous dispersion (A) having a carboxyl group neutralized with a tertiary amine (f) in the molecule and a primary and / or secondary monoamine (B). A method for producing a primary and / or secondary amine-neutralized polyurethane resin aqueous dispersion, which comprises mixing and then removing the liberated tertiary amine.

The present invention includes the following steps. (1) Consist of an organic diisocyanate (a), a polymer polyol (b), an α, α-dimethylolmonocarboxylic acid (c) and, if necessary, a low molecular polyol (d) and / or an amine chain extender (e) Aqueous polyurethane dispersion (A) neutralized with a tertiary amine (f)
And (2) mixing the polyurethane aqueous dispersion (A) with the primary and / or secondary monoamine (B), and then removing the liberated tertiary amine (f).

In the present invention, the organic diisocyanate (a) constituting the polyurethane resin aqueous dispersion (A) having a carboxyl group neutralized with a tertiary amine (f) in the molecule is an aromatic diisocyanate, For example, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), m-xylylene diisocyanate (XDI), naphthalene diisocyanate;
Aliphatic diisocyanates having 2 to 12 carbon atoms, such as hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate, lysine diisocyanate;
Alicyclic diisocyanates having 4 to 18 carbon atoms, for example, 1,4-
Cyclohexane diisocyanate (CDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), methylcyclohexane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, 1,3-diisocyanatomethylcyclohexane (Hydrogenated XDI); Aliphatic diisocyanate having an aromatic ring, such as xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI); Modified products of these diisocyanates (carbodiimide, uretdione, uretimine, burette and / or Modified products of isocyanurate); and mixtures of two or more thereof. Preferred among these are HDI, IPDI, hydrogenated MDI.
And TMXDI.

The polymer polyol (b) is a polyether polyol, for example, one obtained by polymerizing or copolymerizing alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) and / or heterocyclic ether (tetrahydrofuran, etc.). Specifically, polyethylene glycol, polypropylene glycol, polyethylene-polypropylene (block or random) glycol, polyethylene-tetramethylene glycol (block or random), polytetramethylene ether glycol, polyhexamethylene ether glycol, etc .; polyester polyol, for example, fat Group dicarboxylic acids (succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, etc.) and / or aromatic dicarboxylic acids (isophthalic acid, terephthalic acid) Low molecular weight glycol (ethylene glycol, propylene glycol, etc.)
1,4-butanediol, 1,6-hexanediol, 3-methyl
-1,5-pentanediol, neopentyl glycol, 1,4
-Dihydroxymethylcyclohexane etc.), specifically polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyneopentyl adipate diol, polyethylene / butylene adipate diol, polyneopentyl / hexyl Adipate diol,
Poly-3-methylpentane adipate diol, polybutylene isophthalate diol, etc .; polylactone polyols, such as polycaprolactone diol or triol, poly-3-methylvalerolactone diol, etc .; polycarbonate polyols, such as polyhexamethylene carbonate diol; polyolefin polyols, Examples thereof include polybutadiene glycol, polyisoprene glycol or hydrogenated products thereof; and mixtures of two or more thereof. Among the above-exemplified ones, preferred ones are at least one selected from, and
It is a mixture with one or more of. The number average molecular weight of (b) is usually 500 to 5000, preferably 1000 to 4000.

Α, α-Dimethylolmonocarboxylic acid (c)
Is a component used to introduce an anionic hydrophilic group for stably dispersing a polyurethane resin in water, and specific examples include α, α-dimethylolacetic acid, α, α-dimethylolpropionic acid, α , α-Dimethylolbutyric acid, and of these, preferred is α, α-dimethylolpropionic acid.

As a component of (A), a low molecular weight polyol (d) and / or an amine chain extender (e) can be used if necessary.

Examples of (d) include glycols and their alkylene oxide low-molar adducts (number average molecular weight less than 500) listed as the raw materials for the above polyester polyols; bisphenol alkylene oxide low-molar adducts (number average molecular weight less than 500). Trihydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, etc. and low molar adducts of alkylene oxides thereof (number average molecular weight less than 500); and mixtures of two or more thereof.

Examples of (e) include aliphatic polyamines such as ethylenediamine, N-hydroxyethylethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine; alicyclic polyamines such as
4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, isophoronediamine; hydrazines,
Examples thereof include hydrazine, carbodihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, phthalic acid dihydrazide; and mixtures of two or more thereof.

The tertiary amine (f) used for neutralizing the carboxyl group of (A) is a lower alkyl amine,
For example, trimethylamine, triethylamine, tri-n-
Examples include propylamine and tri-n-butylamine. Among these, trimethylamine and triethylamine having a boiling point lower than that of water are particularly preferable because they are easily removed in the step (2).

The method for producing (A) in the present invention is not particularly limited. For example, a hydrophilic organic solvent containing no active hydrogen group in the molecule (for example, acetone, methyl ethyl ketone,
In the presence or absence of tetrahydrofuran, dioxane, and a mixture of two or more thereof, the organic diisocyanate (a), the polymer polyol (b), the α, α-dimethylolmonocarboxylic acid (c), and if necessary, The low-molecular polyol (d) and the isocyanate (a) (NC
O) group and the active hydrogen group of (b) + (c) + (d) in an equivalent ratio of usually 1.1 to 2.0, preferably 1.2 to 1.6 by a one-shot method or a multi-step method, usually at 20 ° C. The terminal NCO is reacted at 150 ° C, preferably 60 ° C to 110 ° C for 2 to 10 hours.
A group-containing urethane prepolymer, which is then neutralized with the tertiary amine (f) or while being neutralized, usually at 10 ° C to 60 ° C, preferably at 20 ° C to 40 ° C in water and / or
Alternatively, a specific example is a method of mixing with an aqueous solution containing an amine chain extender (e) and performing an emulsion elongation reaction until the NCO groups are almost eliminated.

The amount of the α, α-dimethylolmonocarboxylic acid (c) in the above is 0.3 to 5% by weight based on the solid content in the urethane prepolymer as a carboxyl group (--COOH).
It is preferably 0.5 to 4% by weight. If it is less than 0.3% by weight, it is difficult to obtain a stable dispersion, and if it exceeds 5% by weight, the hydrophilicity of the polymer becomes high, so that the water resistance when formed into a coating film is lowered.

The amount of the tertiary amine (f) is usually 0.5 to 1.5 equivalents, preferably 0.7 to 1.3 equivalents, relative to the carboxyl group.

When the amine-based chain extender (e) is used in the above-mentioned emulsion extension reaction, the amount of the (e) is usually 1.1 equivalents or less, preferably 1.0 equivalent to the NCO group in the prepolymer.
It is 5 equivalents or less. If it exceeds 1.1 equivalents, the polymer cannot be polymerized and sufficient resin properties cannot be obtained.

As the primary and / or secondary monoamine (B) used in the step (2), a lower alkylamine such as methylamine, ethylamine, isopropylamine, n-butylamine, dimethylamine, diethylamine is used. , Diisopropylamine, di-n-butylamine and the like; alicyclic amines such as cyclohexylamine and the like;
Heterocyclic amines such as morpholine, pyridine and the like; alkanolamines such as monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine, methylethanolamine, methylisopropanolamine, 2-amino-2-methylpropanol and the like; or these Mixtures of two or more may be mentioned. Among these, preferred are alkanolamines, and particularly preferred are ethanolamine, diethanolamine, isopropanolamine, diisopurpanolamine and 2-amino-2-methyl-1-propanol.

In the step (2), the tertiary amine-neutralized polyurethane resin aqueous dispersion (A) and a predetermined amount of the primary and / or secondary monoamine (B) are usually added in an amount of 10 to 100.
The tertiary amine (f) liberated by mixing at 20 ° C. and then free is usually 20 ° C. to 100 ° C., preferably 40 ° C. to 8 ° C. under normal pressure or reduced pressure.
This is a step of removing at 0 ° C. In this step, (f)
Is quantitatively replaced with (B) and is released into the system.

There is no particular restriction on the timing and mixing method of mixing (A) and (B) in the step (2). For example, when a solvent is used in the step (1), before the solvent is removed. It may be during removal or after removal, but if (B) is added before removing the solvent, the liberated tertiary amine and the solvent can be removed at the same time, which is industrially advantageous.

The amount of (B) depends on the amount of the tertiary amine to be substituted, but is usually 0.5 to 1.5 equivalents, preferably 0.7 to 1.3 equivalents based on the carboxyl group. If it is less than 0.5 equivalent, the hydrolysis resistance of the resin in the state of the aqueous dispersion is lowered, and 1.5
When the amount exceeds the equivalent, it tends to cause a decrease in heat-resistant yellowing upon heat curing when used as a paint.

[0021]

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

Example 1 Polycaprolactone diol [number average molecular weight (hereinafter abbreviated as Mn) 2000] 117.3 parts, poly-3-methylpentane adipate diol (Mn2000) 117.3 parts, 1,4-butanediol 3.3 g, trimethylol 6.4 g of propane, 18.7 parts of α, α-dimethylolpropionic acid, 121.7 parts of IPDI and 146 parts of acetone were charged into a pressure reaction vessel, and the reaction was carried out at 85 ° C. for 6 hours under closed pressure with stirring, and the residual NCO content was 2.5%. Was synthesized. This urethane prepolymer
After cooling to 40 ° C, 12.7 parts of triethylamine was added and stirred and mixed for 30 minutes, and 440 parts was added to 560 parts of ion-exchanged water at 20 ° C in a four-necked Korben while stirring and mixing to emulsify and remain at 40 ° C. A water extension reaction was carried out until the NCO group was eliminated to obtain a tertiary amine-neutralized polyurethane resin water-based dispersion (A-1) containing acetone. Next, 12.8 parts of 2-amino-2-methyl-1-propanol was added to 1000 parts of the (A-1) at 60 ° C., and the mixture was stirred and mixed. Then, while maintaining the same temperature, acetone was added under reduced pressure for about 7 hours. And triethylamine are distilled off,
800 parts of a primary amine-neutralized polyurethane resin aqueous dispersion having a solid content of 40.0%, a viscosity of 200 cps / 25 ° C. and a pH of 10.0 was obtained. The content of triethylamine contained in this dispersion by gas chromatography was 0.08%. A film of the obtained water-based urethane resin dispersion was prepared under the following conditions. <Film preparation conditions> Aqueous urethane resin dispersion was diluted with ion-exchanged water to a solid content of about 20%, poured into a framed glass plate in an amount of 12 g, and allowed to stand horizontally.
It was dried at 0 ° C. for 3 hours and further at 140 ° C. for 30 minutes to form a film (film thickness: about 20 μm). A cured coating film was prepared using the obtained water-based urethane resin dispersion under the following conditions. <Cured coating preparation conditions> Water-based urethane resin dispersion (solid content) 100 parts Cymel 303 (solid content) 15 parts (Mitsui Cyanamid KK) p-toluenesulfonic acid 0.3 parts The above composition was applied to a tin plate (JIS G3303). The composition was applied, dried at room temperature for 30 minutes, and then baked at 120 ° C. for 20 minutes to form a cured coating film (film thickness of about 20 μm).

Example 2 260.6 parts of polycarbonate diol (Mn2000), α, α-
Dimethylolpropionic acid (18.7 parts) and HDI (84.2 parts) were charged into a pressure reaction vessel, and the reaction was carried out at 80 ° C for 2 hours under closed pressure while stirring. After cooling to 40 ° C, 2 mol of ethylene oxide adduct of bisphenol A (Mn330 ) 21.2 parts and 146 parts of acetone are charged, and the mixture is stirred at 80 ° C. under a closed pressure for 3 times.
By reacting for a time, a urethane prepolymer having a residual NCO content of 2.3% was synthesized. This urethane prepolymer was cooled to 40 ° C, 12.7 parts of triethylamine was added, and the mixture was stirred and mixed for 30 minutes, and 440 parts were mixed with 560 parts of 20 ° C ion-exchanged water in a four-neck Kolben.
Part with stirring and mixing to emulsify and leave residual NCO at 40 ° C.
A water extension reaction was carried out until the groups disappeared to obtain a tertiary amine-neutralized polyurethane aqueous dispersion (A-2) containing acetone. Next, to 1000 parts of the (A-2) at 60 ° C., 2-amino-2
1-methyl-1-propanol (12.0 parts) was added, and the rest of Example 1
Perform the same operation as above, solid content 39.5%, viscosity 450cps / 25 ℃,
810 parts of an aqueous polyurethane resin dispersion having a pH of 9.5 was obtained. The content of triethylamine contained in this dispersion by gas chromatography was 0.08%. A film and a cured coating film were prepared under the same conditions as in Example 1 using the obtained water-based urethane resin dispersion.

Example 3 Poly-3-methylpentane adipate diol (Mn3950) 24
8.5 parts, 1,4-butanediol 6.9 parts, trimethylolpropane 3.9 parts, α, α-dimethylolpropionic acid 16.6 parts,
95.3 parts of IPDI and 158 parts of acetone were charged into a pressure reaction vessel, and reacted at 85 ° C. for 6 hours under closed pressure while stirring,
A urethane prepolymer with a residual NCO content of 1.8% was synthesized.
After cooling this urethane prepolymer to 40 ° C., 11.3 parts of triethylamine was added and stirred and mixed for 30 minutes, 456 parts were added to 560 g of 20 ° C. ion-exchanged water in a four-necked Korben while stirring and emulsified, and 40 A water elongation reaction was carried out at 0 ° C. until the residual NCO groups disappeared to obtain an aqueous polyurethane resin dispersion containing acetone (A-3). Then the (A-3)
13.9 parts of diethanolamine was added to 1016 parts at 60 ° C., and then the same operation as in Example 1 was performed to obtain a solid content of 40.5% and a viscosity of 3
50cps / 25 ℃, pH 10.0 Polyurethane Resin Aqueous Dispersion 79
I got 0 copies. The content of triethylamine contained in this dispersion by gas chromatography was 0.10%. Using the obtained polyurethane resin aqueous dispersion, a film and a cured coating film were prepared under the same conditions as in Example 1.

Example 4 Polyethylene isophthalate diol (Mn2000) 234.1
Part, neopentyl glycol 3.9 parts, trimethylolpropane 6.4 parts, α, α-dimethylolpropionic acid 18.7
Parts, 121.7 parts of IPDI and 146 parts of acetone were charged into a pressure reaction vessel and reacted under stirring and closed pressure at 85 ° C. for 5.5 hours to synthesize a urethane prepolymer having a residual NCO content of 2.6%. This urethane prepolymer was cooled to 40 ° C, 12.7 parts of triethylamine was added, and the mixture was stirred and mixed for 30 minutes 44
0 part was added to 760 parts of a 20 ° C ion-exchange aqueous solution in which 10.8 parts of isophoronediamine was dissolved in a four-necked Kolben while stirring and mixing to emulsify, and an extension reaction was carried out at 20 ° C until there were no remaining NCO groups, and acetone was added. A tertiary amine-neutralized polyurethane aqueous dispersion containing (A-4) was obtained. Next, the (A
-4) 12.8 parts of 2-amino-2-methyl-1-propanol was added to 1200 parts at 60 ° C., and then the same operation as in Example 1 was carried out to obtain a solid content of 33.2%, a viscosity of 120 cps / 25 ° C., 1000 parts of an aqueous urethane resin dispersion having a pH of 9.4 was obtained. The content of triethylamine contained in this dispersion by gas chromatography was 0.08%. Using the obtained polyurethane resin aqueous dispersion, a film and a cured coating film were prepared under the same conditions as in Example 1.

Example 5 110.8 parts of polycaprolactone diol (Mn2000), poly-
3-Methylpentane adipate diol (Mn2000) 110.8
, 2.5 parts of 1,4-butanediol, 6.1 parts of trimethylolpropane, 18.7 parts of α, α-dimethylolpropionic acid, 135.8 parts of hydrogenated MDI and 146 parts of acetone are charged into a pressure reaction vessel and sealed with stirring. React under pressure at 85 ℃ for 6 hours,
A urethane prepolymer with a residual NCO content of 2.4% was synthesized.
This urethane prepolymer was cooled to 40 ° C, 12.7 parts of triethylamine was added, and the mixture was stirred and mixed for 30 minutes, 440 parts was mixed with 760 parts of a 20 ° C ion exchange aqueous solution in which 9.0 parts of carbodihydrazide was dissolved in a four-necked Korben. However, the mixture was added and emulsified, and the elongation reaction was carried out at 20 ° C. until the residual NCO groups were exhausted to obtain a tertiary amine-neutralized polyurethane aqueous dispersion (A-5) containing acetone. Then (A-
5) To 1200 parts of the obtained urethane aqueous dispersion, 12.8 parts of 2-amino-2-methyl-1-propanol was added at 60 ° C., and then the same operation as in Example 1 was performed to obtain a solid content of 33.7%, Viscosity 70cps
950 parts of a polyurethane resin aqueous dispersion having a pH of 9.6 at / 25 ° C was obtained. The content of triethylamine contained in this dispersion by gas chromatography was 0.12%. Using the obtained polyurethane resin aqueous dispersion, a film and a cured coating film were prepared under the same conditions as in Example 1.

Comparative Example 1 Polycaprolactone diol (Mn2000) 117.3 parts, poly-
3-Methylpentane adipate diol (Mn2000) 117.3
Parts, 3.3 parts of 1,4-butanediol, 6.4 parts of trimethylolpropane, 18.7 parts of α, α-dimethylolpropionic acid, I
121.7 parts of PDI and 146 parts of acetone were charged into a pressure reaction vessel and reacted under stirring and closed pressure at 85 ° C. for 6 hours to synthesize a urethane prepolymer having a residual NCO content of 2.5%. After cooling this urethane prepolymer to 40 ° C., 12.7 parts of triethylamine was added and 440 parts obtained by stirring and mixing for 30 minutes,
The mixture was added to 560 parts of 20 ° C. ion-exchanged water in a four-necked Korben while stirring and mixing to emulsify, and the water elongation reaction was carried out at 40 ° C. until the residual NCO groups were exhausted. Next, the acetone-containing polyurethane resin aqueous dispersion obtained was distilled off acetone under reduced pressure for 5 hours while stirring at 50 ° C., and then 3.4 parts of triethylamine was added under stirring at normal pressure to obtain a solid content of 40.2%. , Viscosity 23
780 parts of an aqueous urethane resin dispersion having a pH of 10.0 at 0 cps / 25 ° C was obtained. Using the obtained tertiary amine neutralized polyurethane resin aqueous dispersion, a film and a cured coating film were prepared under the same conditions as in Example 1.

Comparative Example 2 Poly-3-methylpentane adipate diol (Mn2000) 2
21.6 parts, 1,4-butanediol 2.5 parts, trimethylolpropane 6.1 parts, α, α-dimethylolpropionic acid 18.7
Parts, 135.8 parts of hydrogenated MDI and 146 parts of acetone were charged into a pressure reaction vessel and reacted under stirring and closed pressure at 85 ° C. for 6 hours to synthesize a urethane prepolymer having a residual NCO content of 2.4%. This urethane prepolymer was cooled to 40 ° C, 12.7 g of triethylamine was added, and the mixture was stirred and mixed for 30 minutes 440
Parts were added to 760 parts of a 20 ° C ion exchange aqueous solution in which 9.0 parts of carbodihydrazide was dissolved in a four-necked Korben with stirring and mixing to emulsify, and an extension reaction was carried out at 20 ° C until there were no remaining NCO groups. Next, the resulting polyurethane resin aqueous dispersion containing acetone was distilled off under reduced pressure for 5 hours while stirring the polyurethane resin aqueous dispersion at 50 ° C., and then 3.4 parts of triethylamine was added at normal pressure with stirring to obtain a solid content of 40.3. %, Viscosity 310c
795 parts of an aqueous urethane resin dispersion having a ps / 25 ° C. and a pH of 10.1 was obtained. Example 1 using the obtained water-based urethane resin dispersion
A film and a cured coating film were prepared under the same conditions as in.

Comparative Example 3 117.3 parts of polycaprolactone diol (Mn2000), poly-
3-Methylpentane adipate diol (Mn2000) 117.3
Parts, 1,4-butanediol 6.4 parts, trimethylolpropane 3.3 parts, α, α-dimethylolpropionic acid 18.7 parts, I
121.7 parts of PDI and 146 parts of acetone were charged into a pressure reaction vessel and reacted under stirring and closed pressure at 85 ° C. for 6 hours to synthesize a urethane prepolymer having a residual NCO content of 2.5%. 440 parts of this urethane prepolymer cooled to 40 ° C were placed in a 4-neck Kolben, and aminoethylethanolamine was added.
10.9 parts, diethanolamine 5.5 parts and acetone 214.4 parts were added and the chain extension reaction was carried out at 40 ° C. for 1 hour with stirring to obtain a terminal NC.
It was prepared with an acetone solution of a polyurethane resin in which O groups were blocked. Next, 13.4 parts of 2-amino-2-methyl-1-propanol was added at 40 ° C, and the mixture was stirred and mixed for 30 minutes, and then 846 parts of deionized water was added dropwise at 20 ° C over 20 minutes to emulsify and disperse the polyurethane aqueous system. As a body, raise the temperature to 50 ° C and distill off acetone under reduced pressure for 5 hours to obtain a solid content of 32.0%, viscosity of 520cps / 25 ° C, pH
1080 parts of an aqueous polyurethane resin dispersion of 10.2 was obtained. A film and a cured coating film were prepared under the same conditions as in Example 1 using the obtained water-based urethane resin dispersion.

Comparative Example 4 117.3 parts of polycaprolactone diol (Mn2000), poly-
3-Methylpentane adipate diol (Mn2000) 117.3
Parts, 1,4-butanediol 3.3 parts g, trimethylolpropane 6.4 parts, α, α-dimethylolpropionic acid 18.7 parts, I
121.7 parts of PDI and 146 parts of acetone were charged into a pressure reaction vessel and reacted at 85 ° C for 6 hours under a closed pressure, and the residual NCO content was 2.5%.
Was synthesized. After cooling this urethane prepolymer to 40 ° C., 15.8 parts of 2-amino-2-methyl-1-propanol was added and stirred and mixed for 30 minutes, 440 parts were mixed with 560 parts of 20 ° C. ion-exchanged water in a four-necked Korben. Although the mixture was added with stirring and mixing, the polyurethane resin aqueous dispersion could not be obtained due to almost coagulation and precipitation.

The following performance tests were conducted on the films and cured coatings prepared in Examples 1 to 5 and Comparative Examples 1 to 3 above.

[Performance test items and test method] Film strength: A film was punched out into a dumbbell-shaped No. 3 to form a test piece, and the tensile strength was measured according to JIS K6301. Pencil hardness: The hardness of the cured coating film was measured according to JIS 5400 using a high-grade pencil defined in JIS S6006. Water resistance: After soaking the cured coating film in ion-exchanged water for 200 hours,
The whitening of the coating film and the blistering state were visually evaluated. (○ No change △ Partial whitening × Total whitening and blistering) Solvent resistance: Acetone was spotted on the cured coating film to determine the change in coating film state. (○ No change △ Swell slightly × Partially dissolved)

The results of the above tests are shown in Table 1.

[0034]

[Table 1]

[0035]

The method for producing the urethane resin aqueous dispersion of the present invention has the following effects. 1. A primary and / or secondary monoamine type and high molecular weight polyurethane resin aqueous dispersion can be easily produced industrially. 2. The urethane resin aqueous dispersion obtained by the production method of the present invention is a thermosetting system using a water-soluble melamine resin as a curing agent in the presence of an acidic catalyst, which can be cured at a relatively low temperature, and has a film strength and A cured product having excellent water resistance can be obtained. From the above effects, the urethane resin aqueous dispersion obtained by the production method of the present invention is a metal, plastic, concrete, paint for ceramics, coating agent, adhesive, etc., particularly high physical properties and low temperature curability. It is useful for applications that require

Claims (4)

(57) [Claims] 1. A mixture of a polyurethane resin aqueous dispersion (A) having a carboxyl group neutralized with a tertiary amine (f) in the molecule and a primary and / or secondary monoamine (B). And then removing the liberated tertiary amine, and a method for producing a primary and / or secondary amine neutralized polyurethane resin aqueous dispersion. 2. The method for producing an aqueous dispersion according to claim 1, which comprises the following steps. (1) From organic diisocyanate (a), polymer polyol (b), α, α-dimethylolmonocarboxylic acid (c), and optionally low-molecular polyol (d) and / or amine chain extender (e) Polyurethane aqueous dispersion (A) constituted and neutralized with a tertiary amine (f)
And (2) mixing the polyurethane aqueous dispersion (A) with the primary and / or secondary monoamine (B) and then removing the liberated tertiary amine (f). 3. The method for producing an aqueous dispersion according to claim 1, wherein the tertiary amine (f) is at least one selected from trimethylamine, triethylamine and tri-n-propylamine. 4. The primary and / or secondary monoamine (B) is selected from monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine, 2-amino-2-methyl-1-propanol. It is at least 1 type, The manufacturing method of the water-based dispersion in any one of Claims 1-3.