JPH06136085A - Production of interivally cross-linked aqueous urethane resin - Google Patents

Abstract

PURPOSE:To obtain an internally cross-linked aqueous urethane resin useful as a coating, adhesive, etc., excellent in solvent resistance and water resistance by subjecting an aqueous urethane prepolymer obtained by a specific method to chain extension reaction and subsequently to a radical polymerization. CONSTITUTION:(A) A terminal NCO-containing urethane prepolymer comprising a diisocyanate, a polyol and a polyol having a carboxyl group (preferably 2,2- dimethylolpropionic acid) is reacted with (B) a compound having a double bond and a hydroxyl group (e.g. hydroxyethyl acrylate) to produce an urethane prepolymer. The carboxyl groups in the urethane prepolymer are neutralized with (C) a basic compound (preferably dimethylethanolamine), and the reaction product is dispersed in water to produce an aqueous urethane prepolymer. The prepolymer is subjected to an elongation reaction and subsequently to a radical polymerization to provide the objective resin. The chain extender is preferably water, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an internal cross-linking type water-based urethane resin which is excellent in solvent resistance and water resistance in water-based urethane resin and is useful as a paint, an adhesive and a surface coating agent.

[0002]

Water-based polyurethane resins are used as sealers or top coats for paints, adhesives, water-based inks, leather, paper, metals, plastics, wood, rubber, inorganic materials, etc. The organic solvent resistance and water resistance are not necessarily sufficient. Amino resins, polyfunctional aziridines, and water-soluble epoxies are used as curing agents in conventional aqueous polyurethane resins.
Although there are proposals to improve the performance, these are two-part solutions and therefore have drawbacks such as workability, stability, temperature dependence, and hydrolysis.

[0003]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above-mentioned problems, the present invention provides a double bond to a part or all of the terminals of a carboxylic acid group-containing urethane prepolymer, and the carboxylic acid of this prepolymer is The internal cross-linking type aqueous urethane resin obtained by neutralizing the group with a basic compound and dispersing it in water, and then performing a radical polymerization reaction of an extension reaction and a double bond is excellent in solvent resistance and water resistance. As a result, they have completed the present invention.

[0004]

Means for Solving the Problems That is, the present invention is as follows. (A) A urethane prepolymer obtained by reacting a urethane prepolymer (a) having an isocyanate group at the terminal, which is composed of diisocyanate, a polyol and a polyol having a carboxylic acid, with a compound (b) having a double bond and a hydroxyl group. (c) is obtained by neutralizing a part or all of the carboxylic acid in the urethane prepolymer with a basic compound (d) and dispersing the aqueous urethane prepolymer (e) in water to cause an elongation reaction and a radical polymerization reaction. A method for producing an internal cross-linking type water-based urethane resin, which comprises: (B) The method for producing an internally crosslinked aqueous urethane resin according to (a) above, wherein the urethane prepolymer (a) has an isocyanate group content of 1.5 to 20.0% (solid content conversion). (C) At least 0. in the urethane prepolymer (a).
The method for producing an internally crosslinked aqueous urethane resin according to (a) above, wherein 5% by weight is a polyol having 3 or more hydroxyl groups. (D) The double bond equivalent of the urethane prepolymer (c) is
The method for producing an internal cross-linking aqueous urethane resin according to the above (a), which is 200 to 2000 g / eq. (E) The urethane prepolymer (c) has an isocyanate group content of 0 to 3.0% (solid content conversion) (a)
A method for producing the internally crosslinked aqueous urethane resin described. (F) The isocyanate group content of the urethane prepolymer (c) is 0% to 3.0%, and the double bond equivalent is 200 to 20.
Urethane prepolymer (a) and / so that it becomes 00g / eq
Alternatively, in the step of synthesizing the urethane prepolymer (c), it is prepared by adding alcohols or secondary amines, and the method for producing an internally crosslinked aqueous urethane resin according to (a) above. (G) The basic compound (d) is ammonia (water), dimethylethanolamine, triethylamine, and the equivalent ratio of the basic compound (basic compound / carboxylic acid group)
Is in the range of 0.5 to 1.5, The method for producing an internal cross-linking aqueous urethane resin according to (A) above. (H) Radical polymerization reaction, urethane prepolymer
(c) The solid content concentration is in the range of 15 to 30% by weight. (I) When the urethane prepolymer (a) is reacted with the compound (b) having a double bond and a hydroxy group, a polymerization inhibitor and / or air is used, and the internal cross-linking type described in (a) above is used. Manufacturing method of water-based urethane resin. (G) The amount of the polymerization inhibitor is 50 to 2000 ppm by weight with respect to the compound (b) having a double bond and a hydroxy group.
The method for producing an internally crosslinked aqueous urethane resin according to (i) above, which is

The internally crosslinkable aqueous urethane resin of the present invention is
For example, it is manufactured as follows. That is, the following diisocyanate is reacted with a polyol and a polyol having a carboxylic acid group to obtain a urethane prepolymer (a) having an isocyanate group at the terminal. Then the urethane prepolymer
A compound having a double bond and a hydroxyl group in (a) (b)
To give a urethane prepolymer (c). Furthermore, some or all of the carboxylic acid groups of this urethane prepolymer (c) were neutralized with a basic compound (d) and dispersed in water to obtain an aqueous urethane prepolymer (e), which was then subjected to elongation reaction and double bond. An internal cross-linking type aqueous urethane resin can be produced by carrying out the radical polymerization reaction. In the production of the above-mentioned aqueous urethane prepolymer (e) and the elongation reaction and the radical polymerization reaction of the double bond, the urethane prepolymer (c) is mixed with the following solvent and / or
Alternatively, it is dissolved or suspended in water and mixed, and a basic compound (which reacts with a carboxyl group to increase hydrophilicity) and the following extender are added dropwise, or the basic compound and the extender are dissolved in a solvent and / or water. , The urethane prepolymer (c) is added dropwise to make the urethane prepolymer hydrophilic and at the same time react with the extender, and then water and a polymerization catalyst are charged in a nitrogen atmosphere to prepare a double bond. Carry out radical polymerization reaction. Further, the internal cross-linking type aqueous urethane resin is obtained by performing solvent removal and dehydration until the concentration of nonvolatile components is 30 to 45%. At this time, the extension reaction and the radical polymerization reaction may be performed at the same time, but the concentration of the solid content of the urethane prepolymer (e) before the radical polymerization reaction is 15 to 30% by weight.
Is preferred. In this case, it is preferable to disperse the urethane prepolymer in water and then add water to disperse the prepolymer in water to adjust the solid content to 15 to 30% by weight. Water may be added at any time before the radical reaction is started, preferably from 30 minutes after dispersion to the addition of the catalyst. The reaction temperature and reaction time for the preparation of the urethane prepolymer (a) and the urethane prepolymer (c) can be carried out under the conditions which are usually carried out.
~ 3 hours is appropriate. The extension reaction or radical polymerization can also be carried out under commonly used conditions, for example, at 60 to 100 ° C for 1 to 3 hours.

The double bond equivalent in the urethane prepolymer (c) in the above reaction is set to 200 to 2000 g / eq, preferably 400 to 1500 g / eq. If the double bond equivalent is 2000 g / eq or more, internal cross-linking is not sufficient, and sufficient performance such as solvent resistance is difficult to develop.
If it is less than / eq, it does not easily form a film when coated, and gelation may occur during the production of the urethane prepolymer. In the above reaction, the isocyanate group content of the urethane prepolymer (c) is set to 0 to 3.0% (solid content conversion). When the isocyanate group content is 3.0% or more, internal crosslinking is insufficient and performance such as solvent resistance is insufficient.
At this time, the isocyanate group content of the urethane prepolymer (c) is 0 to 3.0%, and the double bond equivalent is 200 to 2000.
If necessary, alcohols or secondary amines can be added in the range of g / eq at the stage of synthesizing the urethane prepolymer (a) and / or the urethane prepolymer (c). Further, the amount of carboxylic acid in the urethane prepolymer (c) is set to be 10 or more, preferably 20, and more preferably 25 or more as an acid value (as solid content). When the acid value is 10 or less, self-emulsification is difficult and the particle size becomes large, resulting in lack of stability and precipitation. Furthermore, the equivalent ratio of the basic compound (basic compound / carboxylic acid group) necessary for neutralizing the carboxylic acid group in the urethane prepolymer (c) is 0.5 to 1.5, preferably 0.75.
It is 1.0. If it is less than 0.5, it is difficult to self-emulsify, and the particle size becomes large and lacks stability. If it exceeds 1.5, the particle size becomes too small and the viscosity when dispersed in water becomes too high. Furthermore, when the compound (b) having a double bond and a hydroxyl group is reacted with the urethane prepolymer (a) having an isocyanate terminal, the amount of the polymerization inhibitor is 50 to 2000 ppm, preferably 100 to 2000 by weight ratio with respect to the compound (b). It is set to be 1000 ppm. When the amount of the polymerization inhibitor is 50 ppm or less, there is a risk of gelation due to the radical-reactive double bond during the urethanization reaction, and when it is 2000 ppm or more, the radical reaction after hydration is difficult to proceed.

Examples of the above-mentioned isocyanate compound include 1,4-tetramethylene diisocyanate, 1,
Aliphatic isocyanates such as 6-hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and 2,8-diisocyanate methylcaproate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, methylcyclohexyl Alicyclic diisocyanates such as -2,4-diisocyanate, toluylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthene diisocyanate, difermethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,
One or more of aromatic diisocyanates such as 4-dibenzyl diisocyanate and 1,3-phenylene diisocyanate, chlorinated diisocyanates, brominated diisocyanates, and polyisocyanate compounds that are adducts with water. A mixture is used.

As the polyols used in the present invention, known polyols usually used in the production of urethane resins, for example, diethylene glycol, butanediol, hexanediol, neopentyl glycol, bisphenol A, cyclohexanedimethanol, and triol. Methylolpropane, glycerin, pentaerythritol,
One or a mixture of two or more of polyethylene glycol, polycarbonate polyol, cyclohexanedimethanol, polypropylene glycol, polyester polyol, polycaprolactone, polytetramethylene ether glycol, polythioether polyol, polyacetal polyol, polybutadiene polyol, flange methanol, etc. Can be mentioned. These polyols can be appropriately selected according to the purpose and application, and the required physical properties such as hardness and softness can be easily designed. Any of the above carboxylic acid-containing polyols can be used as long as it imparts a carboxylic acid in a branched form to the urethane prepolymer molecule, but in order to increase the carboxylic acid content in the urethane prepolymer, It is preferably a low molecular weight one having at least one carboxyl group and having 3 to 10 carbon atoms, such as 2,2-dimethylolpropionic acid. Examples of the compound (b) having a double bond and a hydroxyl group used in the present invention include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate,
Examples thereof include hydroxybutyl methacrylate, and one or a mixture of two or more of the above monomers and a compound of propylene oxide, ethylene oxide, or caprolactone.

In the present invention, the urethane prepolymer (a) and /
Or, in the synthesis stage of the urethane prepolymer (c), alcohols or secondary amines added as necessary include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, methyl cellosolve,
Examples thereof include alcohols such as ethyl cellosolve, butyl cellosolve, methyl carbitol, ethyl carbitol and butyl carbitol, and amines such as monoethanolamine, dimethylethanolamine and morpholine. Known substances can be used as the polymerization inhibitor used in the present invention. For example, N-nitroso-N-methylaniline, 3,5
-Ditertiarybutyl-4-hydroxytoluene, paratertiarybutylcatechol, hydroquinone, hydroquinone monomethyl ether, methylhydroquinone,
Parabenzoquinone, thiodiphenylamine, 2,4-dimethyl-6-tert-butylphenol and the like can be mentioned. Air can also be used by utilizing the polymerization inhibition effect of oxygen. In this case, air may be used alone, but it is preferably used in combination with the above polymerization inhibitor. Further, air is preferably continuously blown into the reaction system, and more preferably dry air is used.

As the extender used in the present invention, for example, water or diamines are suitable, and as the polyamines, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine,
Butylenediamine, hexamethylenediamine, cyclohexylenediamine, piperazine, 2-methylpiperazine, phenylenediamine, tolylenediamine, xylenediamine, α, α′-methylenebis (2-chloroaniline) 3,3′-dichloro-α, α '-Biphenylamine, m-xylenediamine, isophoronediamine, N
-Methyl-3,3'-diaminopropylamine and an adduct of diethylenetriamine and an acrylate or a hydrolysis product thereof. As the basic organic compound that reacts with the carboxyl group to impart hydrophilicity, any known compound can be used, and examples thereof include dimethylethanolamine, diethylethanolamine, triethylamine, ammonia (water), diethanolamine. , Triethanolamine, isobasic organic compounds, caustic soda, caustic and the like basic inorganic compounds. Preferred examples include ammonia (water), dimethylethanolamine and triethylamine. At this time, the equivalent ratio of the basic compound (basic compound / carboxylic acid group) is 0.5 to 1.5, preferably 0.75 to 1.0.
Is. If it is 0.5 or less, self-emulsification is difficult and the particle size becomes large and lacks stability. If it is 1.5 or more, the particle size becomes too small and the viscosity when dispersed in water becomes too high.
Known polymerization catalysts can be used in the present invention. For example, azo-based polymerization catalysts such as 2,2′-azobis (2-methylbutyronitrile) and 2,2′-azobis (2,4-dimethylvaleronitrile), decanoyl peroxide, octanoyl peroxide, etc. Examples include peracid catalysts.

As the solvent used in the present invention, an organic solvent usually used for producing a urethane resin can be used.
For example, methyl ethyl ketone, methyl isobutyl ketone,
Examples thereof include ethyl acetate, toluene, xylene, isobutyl acetate, butyl acetate, acetone, dimethylformamide, N-methyl-2-pyrrolidone and diethylene glycol dimethyl ether. Further, the internal cross-linking type water-based urethane resin used in the present invention is, if necessary, an organic solvent, pigment, dye, emulsifier, surfactant, thickener, heat stabilizer, leveling agent, defoaming agent, filler, sedimentation. Inhibitor, film forming aid,
It may contain other conventional components such as a UV absorber, an acid value inhibitor and a viscosity reducing agent. Further, the internally crosslinked aqueous polyurethane resin obtained in the present invention can be used for blending with an acrylic emulsion, a rubber emulsion, or another aqueous resin. Further, the internally cross-linked aqueous urethane resin obtained in the present invention and at least one vinyl monomer such as acrylic acid (ester), methacrylic acid (ester), vinyl chloride, styrene, acrylonitrile, divinylbenzene, vinyl acetate and the like, and / Or an oligomer having one or more acryloyl groups (molecular weight 100 to 100)
It is also possible to copolymerize with (00). In this case, the urethane prepolymer may be blended with the above monomer and / or oligomer, and then dispersed in water and polymerized.

[0012]

EXAMPLES The present invention will now be described with reference to Examples and Comparative Examples in order to more specifically describe the present invention, but the present invention is not limited to these Examples. Example 1 In a 2000 ml four-necked flask equipped with a thermometer, a stirrer, a cooling tube, and a nitrogen (air) introducing tube, 126.8 g of polypropylene glycol having a molecular weight of 1000, 21.5 g of dimethylolpropionic acid, and N-methyl were introduced. 68.8 g of 2-pyrrolidone was charged and the temperature was raised to 90 ° C. while introducing nitrogen to dissolve the contents. Then cool to 40 ° C., 6
8.9 g of acetone was added, and when the internal temperature reached 30 ° C., 97.3 g of tolylene diisocyanate was added dropwise over 1 hour. The internal temperature was maintained at 30 to 40 ° C., the reaction was carried out for 1 hour, then 5.4 g of trimethylolpropane was charged, and the reaction was carried out for another 1 hour. At this time, the isocyanate content was 4.5% / varnish. Hydroquinone (0.15 g) was added to this prepolymer, the atmosphere (oxygen) was changed to 68.8 g of acetone and 48.9 g of hydroxyethyl acrylate, and the reaction was carried out at 50 ° C. for 8 hours. At this time, the isocyanate content was 0.2% / varnish. To this, 1.2 g of methyl alcohol was added and the reaction was continued for 1 hour. The isocyanate content of this urethane prepolymer was 0% / varnish. 481.2 g of deionized water containing 11.7 g of 28% aqueous ammonia
Was maintained at 40 ° C. and the above urethane prepolymer was added dropwise. The reaction system was set to a nitrogen atmosphere, 0.49 g of 2,2′-azobis (2-methylbutyronitrile) and 200 g of deionized water were added, and the reaction was carried out at 80 ° C. for 4 hours. Next, deacetone and dehydration are carried out under reduced pressure, and finally the nonvolatile matter 35.
0% of internally crosslinked aqueous urethane resin was obtained.

Example 2 144.9 g of polypropylene glycol having a molecular weight of 1000, 21.5 g of dimethylolpropionic acid and 68.7 g of N-methyl-2-pyrrolidone were charged in the same four-necked flask as in Example 1. While introducing nitrogen, the temperature was raised to 90 ° C. to dissolve the contents. Then cool to 40 ° C., 6
After adding 8.7 g of acetone, when the internal temperature reached 30 ° C., 97.4 g of tolylene diisocyanate was added dropwise over 1 hour. The internal temperature was kept at 30 to 40 ° C., the reaction was carried out for 1 hour, then 9.1 g of trimethylolpropane was charged, and the reaction was carried out for another 1 hour. At this time, the isocyanate content was 3.1% / varnish. Hydroquinone (0.15 g) was charged into this prepolymer, the air (oxygen) atmosphere was switched to, and 68.7 g of acetone and 27.2 g of hydroxyethyl acrylate were charged, and the reaction was carried out at 50 ° C. for 5 hours. The isocyanate content of this urethane prepolymer was 0.6% / varnish. 401.0 g of deionized water containing 12.9 g of dimethylethanolamine
The above-mentioned urethane prepolymer was added dropwise while maintaining the temperature at ℃. The reaction system was made a nitrogen atmosphere, 0.14 g of 2,2′-azobis (2-methylbutyronitrile) and 200 g of deionized water were added, and the reaction was carried out at 80 ° C. for 4 hours. Next, deacetone and dehydration were performed under reduced pressure to finally obtain an internally crosslinked aqueous urethane resin having a nonvolatile content of 40.0%.

Example 3 In the same four-necked flask as in Example 1, 52.2 g of a polyester polyol having a molecular weight of 500 (Q4646B, manufactured by Mitsui Toatsu Chemicals, Inc.) and dimethylolpropionic acid 2 were added.
1.5 g and 68.3 g of N-methyl-2-pyrrolidone were charged, the temperature was raised to 90 ° C. while introducing nitrogen, and the contents were dissolved. Next, the mixture was cooled to 70 ° C., 68.3 g of ethyl acetate was added, and when the internal temperature reached 80 ° C., 183.2 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate was charged. Inner temperature is 90 ° C
The temperature was raised to 1, the reaction was carried out for 2 hours, then 11.8 g of trimethylolpropane was charged, and the reaction was carried out for another 2 hours. At this time, the isocyanate content was 9.2% / varnish. This prepolymer was charged with 0.15 g of hydroquinone, and the atmosphere was changed to an air (oxygen) atmosphere. Ethyl acetate 68.3
g, 30.9 g of hydroxypropyl methacrylate and 69.6 g of butyl cellosolve were charged, and the reaction was carried out at 90 ° C. for 5 hours. The isocyanate content of this urethane prepolymer was 0.5% / varnish. 16.2 g of triethylamine was added to the urethane prepolymer, 481.0 g of deionized water was kept at 40 ° C., and the above urethane prepolymer was added dropwise. The reaction system was made to have a nitrogen atmosphere, 0.15 g of 2,2′-azobis (2-methylbutyronitrile) and 200 g of deionized water were added, and the reaction was carried out at 80 ° C. for 4 hours. Next, deacetic acid removal and dehydration were performed under reduced pressure to finally obtain an internally crosslinked aqueous urethane resin having a nonvolatile content of 35.0%.

Example 4 In the same four-necked flask as in Example 1, 73.9 g of a polyester polyol having a molecular weight of 500 (Q4646B, manufactured by Mitsui Toatsu Chemicals, Inc.) and 2 parts of dimethylolpropionic acid were used.
1.5 g and 68.3 g of N-methyl-2-pyrrolidone were charged, the temperature was raised to 90 ° C. while introducing nitrogen, and the contents were dissolved. Next, the mixture was cooled to 70 ° C., 68.3 g of ethyl acetate was added, and when the internal temperature reached 80 ° C., 143.6 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate was charged. Internal temperature 9
The temperature was raised to 0 ° C., the reaction was carried out for 2 hours, then 16.7 g of trimethylolpropane was charged, and the reaction was carried out for another 2 hours.
At this time, the isocyanate content was 7.3% / varnish. Hydroquinone (0.15 g) was added to this prepolymer, and the atmosphere was changed to an air (oxygen) atmosphere. Ethyl acetate 68.
3 g, hydroxypropyl methacrylate 43.8 g,
After charging 55.2 g of butyl cellosolve, the reaction was carried out at 90 ° C. for 5 hours. The isocyanate content of this urethane prepolymer was 0.5% / varnish. NK ester 9
30 g of PG (manufactured by Shin-Nakamura Chemical Co., Ltd.) and 16.2 g of triethylamine were added to the urethane prepolymer, and 477.9 g of deionized water was kept at 40 ° C. and the above urethane prepolymer was added dropwise. The reaction system is set to a nitrogen atmosphere and 2,2 '
-Azobis (2-methylbutyronitrile) 0.37 g,
400 g of deionized water was added and the reaction was carried out at 80 ° C. for 4 hours. Next, deacetic acid removal and dehydration were performed under reduced pressure to finally obtain an internally crosslinked aqueous urethane resin having a nonvolatile content of 35.0%.

Example 5 In the same four-necked flask as in Example 1, 95.8 g of polytetramethylene ether glycol having a molecular weight of 2000, 21.5 g of dimethylolpropionic acid and N-methyl-2-
Charge 68.3 g of pyrrolidone and introduce 9 while introducing nitrogen.
The temperature was raised to 0 ° C. to dissolve the contents. Next, the mixture was cooled to 70 ° C., 68.3 g of ethyl acetate was added, and when the internal temperature reached 80 ° C., 3-isocyanatomethyl-3,5,5
-Trimethylcyclohexyl isocyanate 122.3
g was charged. The internal temperature was raised to 90 ° C., the reaction was carried out for 2 hours, then 13.2 g of trimethylolpropane was charged, and the reaction was carried out for another 2 hours. At this time, the isocyanate content was 7.3% / varnish. Hydroquinone (0.15 g) was charged into this prepolymer, and the atmosphere (oxygen) was changed to 68.3 g of ethyl acetate, 46.7 g of hydroxypropyl methacrylate and 1.0 g of methyl alcohol, and the reaction was carried out at 90 ° C for 5 hours. . The isocyanate content of this urethane prepolymer was 0.5% / varnish. Neopentyl glycol diacrylate 30 g,
16.2 g of triethylamine was added to the urethane prepolymer, and 477.9 g of deionized water was kept at 40 ° C., and the above urethane prepolymer was added dropwise. The reaction system was made a nitrogen atmosphere and 2,2'-azobis (2-methylbutyronitrile)
0.77 g and 400 g of deionized water were added and the reaction was carried out at 80 ° C. for 4 hours. Next, deacetic acid removal and dehydration were performed under reduced pressure to finally obtain an internally crosslinked aqueous urethane resin having a nonvolatile content of 35.0%.

Example 6 In the same four-necked flask as in Example 1, 82.1 g of a polyester polyol having a molecular weight of 500 (Q4646B, manufactured by Mitsui Toatsu Chemicals, Inc.) and dimethylolpropionic acid 2 were used.
1.5 g and 34.2 g of N-methyl-2-pyrrolidone were charged, the temperature was raised to 90 ° C. while introducing nitrogen, and the contents were dissolved. Next, the mixture was cooled to 30 ° C., 85.7 g of methyl ethyl ketone was added, 129.1 g of tolylene diisocyanate was added dropwise over 1 hour while keeping the internal temperature at 30 to 40 ° C. The reaction is carried out for 1 hour, then trimethylolpropane 1
8.5 g was charged and the reaction was further performed for 1 hour. At this time, the isocyanate content was 4.7% / varnish. This prepolymer was charged with 0.15 g of hydroquinone, and the atmosphere (oxygen) was changed to methyl ethyl ketone 85.7.
g, hydroxyethyl acrylate 48.7 g after charging 6
The reaction was carried out at 0 ° C for 5 hours. The isocyanate content of this urethane prepolymer was 0.3% / varnish.
480.0 g of deionized water containing 14.3 g of dimethylethanolamine was maintained at 40 ° C. and the above urethane prepolymer was added dropwise. The reaction system is set to a nitrogen atmosphere and 2,2 '
-Azobis (2-methylbutyronitrile) 0.39 g,
200 g of deionized water and 30 g of N-butyl acrylate were added and the reaction was carried out at 80 ° C. for 4 hours. Next, demethyl ethyl ketone and dehydration are performed under reduced pressure to finally obtain a nonvolatile content of 35.0.
% Of the internally crosslinked aqueous urethane resin was obtained.

Comparative Example 1 In the same four-necked flask as in Example 1, 106.9 g of a polyester polyol having a molecular weight of 500 (Q4646B, manufactured by Mitsui Toatsu Chemicals, Inc.), 21.5 g of dimethylolpropionic acid and N-methyl were used. -2-pyrrolidone 68.7g
It was charged and the temperature was raised to 90 ° C. while introducing nitrogen to dissolve the contents. Next, the mixture was cooled to 40 ° C., 68.7 g of acetone was added, and when the internal temperature reached 30 ° C., 144.8 g of tolylene diisocyanate was added dropwise over 1 hour. The internal temperature was kept at 30 to 40 ° C., the reaction was carried out for 1 hour, then 13.4 g of trimethylolpropane was charged, and the reaction was carried out for another 1 hour. At this time, the isocyanate content was 6.
It was 1% / varnish. Hydroquinone (0.15 g) was charged into this prepolymer, the air (oxygen) atmosphere was switched to, and 68.7 g of acetone and 13.4 g of hydroxyethyl acrylate were charged, followed by reaction at 50 ° C. for 5 hours. The isocyanate content of this urethane prepolymer was 4.0.
% / Varnish. Dimethyl ethanolamine 12.
481.0 g of deionized water containing 9 g was kept at 40 ° C. and the above urethane prepolymer was added dropwise. The reaction system is set to a nitrogen atmosphere, 0.02 g of 2,2'-azobis (2-methylbutyronitrile) and 200 g of deionized water are added, and the temperature is set to 80 ° C.
The reaction was carried out for 4 hours. Next, deacetone and dehydration were performed under reduced pressure to finally obtain an aqueous urethane resin having a nonvolatile content of 40.0%.

Comparative Example 2 In the same four-necked flask as in Example 1, 90.4 g of polypropylene glycol having a molecular weight of 2000, 55.7 g of 1.6 hexanediol and 17.9 of dimethylolpropionic acid were used.
g, 68.9 g of N-methyl-2-pyrrolidone,
While introducing nitrogen, the temperature was raised to 90 ° C. to dissolve the contents. Next, the mixture was cooled to 30 ° C., 68.9 g of acetone was added, 131.4 g of tolylene diisocyanate was added dropwise over 1 hour while keeping the internal temperature at 30 to 40 ° C. The reaction was carried out for 5 hours, then 4.5 g of trimethylolpropane and 68.9 g of acetone were charged, and the reaction was carried out for another 1 hour. At this time, the isocyanate content of the urethane prepolymer is 0.8
% / Varnish. Dimethyl ethanolamine 10.
482.5 g of deionized water containing 7 g was kept at 40 ° C. and the above urethane prepolymer was added dropwise. Next, deacetone and dehydration are performed under reduced pressure to finally obtain a nonvolatile content of 37.0%.
A water-based urethane resin of

Comparative Example 3 In the same four-necked flask as in Example 1, 46.9 g of polypropylene glycol having a molecular weight of 2000, 17.9 g of dimethylolpropionic acid and 6 parts of N-methyl-2-pyrrolidone were added.
Charge 8.9g and raise the temperature to 90 ° C while introducing nitrogen,
The contents were dissolved. Then cool to 30 ° C., 68.9 g
Of methyl ethyl ketone was added, 130.9 g of tolylene diisocyanate was added dropwise over 5 hours while keeping the internal temperature at 30 to 40 ° C. The reaction was carried out for 5 hours, then 1.3 g of trimethylolpropane was charged, and the reaction was further carried out for 1 hour. At this time, the isocyanate content was 2.9% / varnish. This prepolymer was charged with 0.15 g of hydroquinone, and the atmosphere (oxygen) was changed to 68.9 g of methyl ethyl ketone and 25.6 g of hydroxyethyl acrylate.
After charging, the reaction was carried out at 60 ° C. for 5 hours. The isocyanate content of this urethane prepolymer was 0.8% / varnish. 482.5 g of deionized water containing 10.7 g of dimethylethanolamine was maintained at 40 ° C. and the above urethane prepolymer was added dropwise. The reaction system was set to a nitrogen atmosphere, and 2,2'-azobis (2-methylbutyronitrile)
0.13 g and 200 g of deionized water were added and the reaction was carried out at 80 ° C. for 4 hours. Then demethyl ethyl ketone under reduced pressure,
It was dehydrated to finally obtain an aqueous urethane resin having a nonvolatile content of 35.0%. Evaluation of solvent resistance and water resistance Deionized water was added as necessary to the internally crosslinked aqueous urethane resins of Examples 1 to 6 and the aqueous urethane resins of Comparative Examples 1 to 3 to adjust the nonvolatile content to 35%. And a mild steel plate (JIS.G.3141) was coated with a bar coater so as to have a thickness of 10 microns after drying. The coating film at a temperature of 20
It was dried for 7 days in a constant temperature and constant humidity chamber at a temperature of 60 ° C. and a humidity of 60%, and subjected to a performance test.

[0021]

Test Method and Evaluation Criteria Solvent Resistance: A solvent is soaked in gauze and the coating surface is rubbed 50 times and the surface condition is observed (Migaki mild steel plate) ⊚: The condition before the test is maintained ○: Slightly glossed Δ: Lusterless ×: Dissolved coating film within 50 reciprocations Water resistance: Immersed in water at 20 ° C. for 8 hours and observed whitening state 1 hour after taking out (glass plate) ◎: No whitening Δ: Partly whitening ×: Whitening (no transparency at all)

[0023]

INDUSTRIAL APPLICABILITY The internally crosslinked aqueous urethane resin obtained in the present invention is excellent in solvent resistance and water resistance.
More clear.

Claims (10)

[Claims] 1. A urethane obtained by reacting a urethane prepolymer (a) having an isocyanate group at the terminal, which is composed of diisocyanate, a polyol and a polyol having a carboxylic acid, with a compound (b) having a double bond and a hydroxyl group. The prepolymer (c) is a compound in which a part or all of the carboxylic acid in the urethane prepolymer is a basic compound.
Aqueous urethane prepolymer neutralized with (d) and dispersed in water
A method for producing an internally crosslinked aqueous urethane resin, which comprises subjecting (e) to an elongation reaction and a radical polymerization reaction. 2. The method for producing an internally crosslinked aqueous urethane resin according to claim 1, wherein the urethane prepolymer (a) has an isocyanate group content of 1.5 to 20.0% (solid content conversion). 3. The method for producing an internally crosslinked aqueous urethane resin according to claim 1, wherein at least 0.5% by weight of the urethane prepolymer (a) is a polyol having three or more hydroxyl groups. 4. The method for producing an internally crosslinked aqueous urethane resin according to claim 1, wherein the double bond equivalent of the urethane prepolymer (c) is 200 to 2000 g / eq. 5. The method for producing an internally crosslinked aqueous urethane resin according to claim 1, wherein the isocyanate group content of the urethane prepolymer (c) is 0 to 3.0% (solid content conversion). 6. The urethane prepolymer (c) has an isocyanate group content of 0% to 3.0% and a double bond equivalent weight of 200 to.
At the synthesis stage of the urethane prepolymer (a) and / or the urethane prepolymer (c) so as to be 2000 g / eq,
The method for producing an internally crosslinked aqueous urethane resin according to claim 1, which is prepared by adding alcohols or secondary amines. 7. The basic compound (d) is ammonia (water), dimethylethanolamine, triethylamine, and the equivalent ratio of the basic compound (basic compound / carboxylic acid group) is 0.5 to 1.5. The method for producing an internally crosslinked aqueous urethane resin according to claim 1, wherein 8. The method for producing an internally crosslinked aqueous urethane resin according to claim 1, wherein the radical polymerization reaction is carried out at a solid concentration of the urethane prepolymer (c) in the range of 15 to 30% by weight. 9. The internal cross-linking according to claim 1, wherein a polymerization inhibitor and / or air is used when the urethane prepolymer (a) is reacted with the compound (b) having a double bond and a hydroxy group. Manufacturing method of mold-type water-based urethane resin. 10. A weight ratio of the polymerization inhibitor to the compound (b) having a double bond and a hydroxy group is 50 to 200.
It is 0 ppm, The manufacturing method of the internal bridge | crosslinking type | mold aqueous urethane resin of Claim 9.