JPH0445120A - Curable resin - Google Patents

Abstract

PURPOSE:To provide a water-soluble or dispersible curable resin suitable for coatings, etc., by blocking a part of isocyanate groups of a polymer having a glycidyl group and the isocyanate groups and reacting the glycidyl group and the remaining isocyanate groups with an alkanolamine. CONSTITUTION:A polymer having a glycidyl group and two or more isocyanate groups and having a number-average mol.wt. of 500-50,000 is allowed to react with a blocking agent (e.g. phenol) to block a part of the isocyanate groups, and the remaining isocyanate groups and the glycidyl group are made to react with an alkanolamine [preferably 2-(methylamine)ethanol, etc.,] to prepare a low temperature-curable resin having the blocked isocyanate groups, a secondary or tertiary amino group or quaternary ammonium group and a hydroxyl group while preventing the gelling, coloring, etc., of the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel polymer having a blocked isocyanate group and a hydroxyl group, which are complementary reactive groups, in one molecule, which is particularly useful as a resin for water-based paints, etc. Regarding self-curing resin.

Prior art and its problems An unsaturated monomer containing a blocked isocyanate group, an unsaturated monomer containing a hydroxyl group, and an unsaturated monomer containing a tertiary amino group or/and a quaternary ammonium group are copolymerized into the same molecule. An aqueous crosslinking curable composition in which a complementary reactive group is introduced, the tertiary amino group is then neutralized with an acid, etc., and then dissolved in a mixture of a hydrophilic organic liquid and water is already known. (Japanese Patent Application Laid-Open No. 64-87606).

However, since a derivative of α-methylstyrene is used as the blocked isocyanate group-containing unsaturated monomer, the polymerization rate becomes insufficient when an azo polymerization initiator is used. In order to increase this polymerization rate, if a peroxide type or dialkyl peroxycarbonate type initiator is used, 1
Since it is necessary to carry out polymerization at a high temperature of 00°C or higher, the blocking agent dissociates during the polymerization reaction, and due to the presence of tertiary amino groups, the regenerated isocyanate groups and hydroxyl groups react, resulting in thickening and thickening. It is not preferable because it will gel.

Additionally, when using an isocyanate group-containing unsaturated monomer blocked with an oxime-based blocking agent, the blocking agent dissociates even at a low temperature of about 100°C, and reacts with the hydroxyl group-containing monomer during the polymerization reaction to form a gel. There is. In particular, when using isocyanate group-containing polymerizable monomers blocked with phenol-based or oxime-based blocking agents, the polymerization reaction is carried out at a high temperature (approximately 120 to 140°C), which has the disadvantage of causing significant coloring during polymerization. In addition, since the dissociation temperature of blocking agents other than these becomes high, it becomes necessary to heat the obtained self-curing resin to a higher temperature (approximately 170°C or higher) to cure it, and it becomes necessary to heat the obtained self-curing resin to a higher temperature (approximately 170°C or higher). It's hard to get things.

On the other hand, as is well known, the importance of water-based paints is increasing from the viewpoint of preventing air pollution and saving resources, but water-soluble melamine resins are mainly used as crosslinking agents, and the curability and coating performance are There is a problem in terms of

Furthermore, conventional blocked isocyanate crosslinking agents are difficult to use in aqueous systems.

Means for Solving the Problems In view of the above-mentioned circumstances, the inventors of the present invention have made extensive studies and have solved the problems such as gelation and coloring during the polymerization reaction, as well as a decrease in the polymerization rate. We have now invented a cationic self-curing resin that can be cured even when heated at the following low temperatures, has a blocked isocyanate group and a hydroxyl group in one molecule, and is soluble or dispersible in water.

That is, the present invention comprises: (1) blocking a part of the isocyanate groups in a polymer skeleton having a glycidyl group and two or more isocyanate groups in one molecule and having a number average molecular weight of 500 to 50,000;
Next, the glycidyl group and the remaining end-blocked isocyanate group are reacted with an alkanolamine to introduce a blocked isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base, and a hydroxyl group into one molecule. curable resin, (1) blocking all of the isocyanate groups in the polymer skeleton having a glycidyl group and two or more isocyanate groups in one molecule and having a number average molecular weight of 500 to 50,000;
A self-curing resin characterized in that the glycidyl group is then reacted with an alkanolamine to introduce a block isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base and a hydroxyl group into one molecule. (1) Blocking all of the isocyanate groups in the polymer skeleton with a number average molecular weight of 500 to 50,000 and having a glycidyl group and two or more isocyanate groups in one molecule, and then reacting the glycidyl groups with primary to tertiary amines. A self-curing resin characterized by introducing a blocked isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base and a hydroxyl group into one molecule, and ■ any of the above ■ to ■. An aqueous self-curing resin obtained by neutralizing amino groups in the self-curing resin with an acid component.

The composition, manufacturing method, uses, etc. of the self-curing resin of the present invention will be explained in detail.

A polymer having a glycidyl group and two or more isocyanate groups in one molecule and having a number average molecular weight of 500 to 50,000 (hereinafter sometimes abbreviated as "NCO polymer") is
Glycidyl group-containing polymerizable unsaturated monomer (hereinafter sometimes abbreviated as rGC monomer) and isocyanate group-containing polymerizable unsaturated monomer (hereinafter sometimes abbreviated as rNco monomer) ) as an essential component, and can be obtained by copolymerizing with other monomers as necessary.

First, the GC monomer is a compound having at least one glycidyl group and at least one polymerizable unsaturated bond in one molecule, and specifically includes 3,4-epoxycyclohexylmethyl (meth)acrylate, aryl glycidyl ether, and Examples include glycidyl (meth)acrylate. It is preferable that this GC monomer does not have a functional group that easily reacts with an isocyanate group.

The NGO monomer is a compound having at least one free isocyanate group and at least one polymerizable unsaturated bond in one molecule, such as methacryloyl isocyanate, 2-isocyanate ethyl methacrylate, m- or p-isopropenyl One or more selected from -α,α'-dimethylbenzyl isocyanate and an adduct of a hydroxyl group-containing vinyl monomer and a diisocyanate compound in a molar ratio of 1:1, among which,
Especially m- or p-isopropenyl-α.

α′-dimethylbenzyl isocyanate is preferred.

Although the NCO polymer contains the above-mentioned GC monomer and NGO monomer as essential components, other monomers can be used in combination as necessary.

Other monomers are active hydrogens that react easily with isocyanate groups (e.g. -〇HS>NH, -NH2, -COOH, etc.)
Polymerizable monomers that do not have, for example, styrene,
Aromatic vinyl monomers such as α-methylstyrene and vinyltoluene; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate
Acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate
Acrylate, (meth)acrylic acid esters such as benzyl (meth)acrylate; Viscose 3F, Viscose 3MF
, 8F and 8MF (all manufactured by Osaka Organic Chemical Co., Ltd.)
(trade name), perfluorocyclohexyl (meth)acrylate, N-2-propyl perfluorooctane sulfonic acid amidoethyl (meth)acrylate, vinyl fluoride, vinylidene fluoride and other fluorine-containing vinyl monomers, N,
Nitrogen-containing vinyl monomers such as N'-diethyl (meth)acrylamide; vinyl ether monomers such as vinyl ethyl ether and vinyl butyl ether; and alkyl etherified products of methylolacrylamide, (meth)acrylamide, (meth)acrylic Acid chloride, vinyl chloride, vinylidene chloride, (meth)acrylonitrile, γ-
Examples include methacryloxyalkyltrimethoxysilane, which are appropriately selected depending on desired performance and used singly or in combination of two or more.

The composition ratio of the above monomers in the NCO polymer may be within the range of having one or more glycidyl groups and two or more isocyanate groups in one molecule of the polymer, specifically,
Based on the total amount of the above three types of monomers, GC monomer is
30% by weight, especially 5-20% by weight, NGO monomers 5-6
0% by weight, especially 20-55% by weight and 92-10% by weight, especially 75-25% by weight of other monomers, respectively, are preferred.

The production of NGO polymers is carried out by copolymerizing the above monomer components in an inert organic solvent without active hydrogen.

An inert organic solvent is a functional group that reacts with an isocyanate group (e.g., hydroxyl group, amino group, carboxyl group, etc.)
For example, one or a mixed solvent of two or more selected from organic solvents such as aliphatic hydrocarbons, aromatics, esters, and ketones is used.

If the resin of the present invention is used in a water-based paint, the organic solvent used for this copolymerization is preferably a hydrophilic or water-soluble solvent, such as diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, and the like. However, care must be taken when using these two types of solvents since there is a risk of explosion during the reaction if a peroxide-based initiator is used. Other examples include N-methyl-2-pyrrolidone, dimethylformamide, and methyl cellosolve acetate. Since these hydrophilic solvents may contain water, it is preferable to dehydrate them in advance.

When these solvents are used during polymerization, they can be directly diluted with water.

On the other hand, during polymerization, a copolymer is synthesized in a water-insoluble organic solvent, and after the completion of the reaction, the solvent is removed under reduced pressure, etc., and the resulting powder is either concentrated or spray-dried. It can be converted into an aqueous liquid by dissolving or dispersing it in a mixed liquid with an organic solvent, or by an azeotropic method.

Examples of the water-insoluble organic solvent in this case include toluene, xylene, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl amyl ketone, diethyl ketone, ethyl butyl ketone, ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, Cellosolve acetate, carpitol acetate, heptane, cyclohexane, etc. can be used.

The copolymerization reaction of the above monomer components for producing the NGO polymer is usually carried out at a temperature of 50 to 180°C using a radical polymerization initiator. The molecular weight can be adjusted by adjusting the reaction concentration,
This is carried out by adjusting the amount of initiator, etc. Generally, the reaction concentration ranges from 20 to 80% by weight of polymer.

Radical polymerization initiators include, for example, organic peroxides such as benzoyl peroxide, lauroyl peroxide, caproyl peroxide, a-butyl peroctoate, and diacetyl peroxide; azobisisobutyronitrile, azobis α, γ-dimethyl Azo catalysts such as valeronitrile, dimethyl α, α′-azoisobutyrate; dialkyl peroxydicarbonates such as diisopropyl peroxycarbonate; and
A redox initiator or the like is used.

The concentration of the polymerization initiator is 0.01 to 15% by weight of the total monomers,
In particular, it is preferably within the range of 0.1 to 10% by weight.

Further, instead of using a polymerization initiator, electron beams, ultraviolet rays, etc. can be used, and ionic polymerization and group transfer polymerization methods can also be used.

The copolymerization reaction is usually carried out at a temperature of 50 to 180'C. However, when using isopropenyl-α,α-dimethylbenzyl isocyanate, a peroxide-based or carbonate-based initiator is used to increase the polymerization rate, and the reaction temperature is set at a high temperature of 100°C or higher. It is preferable to do so.

More preferably, when an acrylate monomer is used, it is easy to obtain an NGO polymer with a high polymerization rate.

The molecular weight of the NCO polymer is 500 to 50 in number average molecular weight.
000, preferably in the range of 1,000 to 30,000; if it is less than 500, the mechanical strength and weather resistance of the cured coating film obtained using it will deteriorate, and if it is more than 50,000, the viscosity of the copolymer solution will be significantly reduced. Moreover, it becomes difficult to convert to water-based.

Although this NGO polymer has glycidyl groups and isocyanate groups, it does not contain any active hydrogen that easily reacts with the isocyanate groups.

The self-curing resin of the present invention has a blocked isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base, and a hydroxyl group in one molecule. block some of the
Next, the glycidyl group and the remaining isocyanate group are reacted with alkanolamine [Self-curing resin (A)]
, or block all of the isocyanate groups, and then react the glycidyl groups with an alkanolamine [
[Self-curing resin (B)] or by reacting 11 to tertiary amino acids [Self-curing resin (C)].

The self-curing resin (A) is a self-curing resin characterized by blocking a part of the isocyanate groups in the NGO polymer skeleton, and then reacting the glycidyl groups and the remaining end-blocked isocyanate groups with an alkanolamine. It is a synthetic resin.

After some of the free isocyanate groups contained in the NGO polymer are reacted with a blocking agent, the NCO polymer contains glycidyl groups, free end-blocked isocyanate groups, and blocked isocyanate groups.

As the blocking agent, for example, phenol, cresol, xylenol, p-ethylphenol, O-isopropylphenol, p-jeN-butylphenol, p-jeN-butylphenol,
-jerj- Phenols such as octylphenol, thymol, p-naphthol, p-nitrophenol, p-talolophenol; methanol, ethanol, propatool, butanol, ethylene glycol, methyl cellosolve, butyl cellosolve, methyl calpitol, benzyl alcohol, Alcohols such as phenyl cellosolve, furfuryl alcohol, and cyclohexanol; activated methylenes such as dimethyl malonate, diethyl malonate, and ethyl acetoacetate; mercaptans such as butyl mercaptan, thiophenol, and tert-dodecyl mercaptan; acetanilide, acedoanidic, Acid amides such as acetate amide and benzamide; succinimide,
Imides such as maleic acid imide; diphenylamine,
Amine type such as phenylnaphthylamine, aniline, carbazole; Imidazole type such as imidazole, 2-ethylimidazole; Urea type such as urea, thiourea, ethylene urea; Phenyl N-phenylcarbamate, 2-
Carbamate types such as oxazolidone; Imine types such as ethyleneimine; Oxime types such as formaldoxime, acetaldoxime, methyl ethyl ketoxime, and cyclohexanone oxime; Sulfite types such as sodium bisulfite and potassium bisulfite; ε-caprolactam, Examples include lactams such as δvalerolactam, γ-butyrolactam, and β-propiolactam; particularly preferred are phenols, lactams, alcohols, and oximes.

The reaction between the NGO polymer and the blocking agent is carried out by blending the blocking agent into an organic solution of the NGO polymer, and usually at a reaction rate of 20 to 150%.
It is carried out at a temperature of °C. Furthermore, a tin-based catalyst may be used if necessary.

The amount of blocking agent to be added is determined by calculating the number of moles of isocyanate groups to be blocked in advance, depending on the amount of hydroxyl groups to be introduced into the NGO polymer in the next step, and determining the amount of blocking agent to be added. Specifically, it is preferable to determine the blending amount so that 5 to 95 mol%, preferably 20 to 80 mol%, of all free isocyanate groups contained in the NGO polymer are blocked.

Next, the remaining end-blocked isocyanate groups and glycidyl groups contained in the partially blocked NGO polymer as described above are reacted with an alkanolamine to form a blocked isocyanate group-containing NCO polymer with further hydroxyl groups and secondary or tertiary amino groups. Alternatively, the self-curing resin (A) of the present invention can be obtained by introducing a quaternary ammonium base.

As the alkanolamine, primary or secondary amines can be used, such as 2-(methylamino)ethanol, 2-(n-butylamino)ethanol, 2-(
Dodecylamino)ethanol includes mono- or di-alkanolamines such as 1-mono(or di)ethanolamine, diisopropanolamine, and 4-piperidineethanol, and among these, particularly preferred are 2-(methylamino)ethanol, Examples include jetanolamine.

The reaction between the isocyanate group or glycidyl group and the amino group of the alkanolamine is very fast and is usually completed in a short time at about room temperature. In this step, both functional groups (blocked isocyanate group and hydroxyl group) are introduced into the NCO polymer. Therefore, if the reaction with alkanolamine is allowed to proceed at a higher temperature than necessary, the blocking agent will partially dissociate and a reaction between both functional groups will occur, resulting in thickening or gelation. Preferably it is carried out at temperature.

In principle, the alkanolamine is preferably blended in an amount necessary to react with all of the end-blocked isocyanate groups and glycidyl groups remaining in the NGO polymer after blocking.

Further, among alkanolamines, when dialkanolamine is used, double the amount of hydroxyl groups can be introduced compared to monoalkanolamine, and the efficiency is good.

In the self-curing resin (A), if the amounts of blocked isocyanate groups and hydroxyl groups are equal, the degree of crosslinking as a self-crosslinking coating film will be the highest. It is preferable that either one of the functional groups is in excess in consideration of the adhesion with the
Suitable hydroxyl value (mgKOH/g) is 20 to 250, isocyanate value (g/10100O is 15 to 250, and amine value (mgKOH/g) is 25 to 100.

The self-curing resin (B) blocks all isocyanate groups in the NGO type O polymer skeleton, and then reacts the glycidyl group with an alkanolamine to form a secondary or tertiary amino group or a quaternary ammonium base and a hydroxyl group. This is a self-curing resin characterized by incorporating the following.

Blocking of isocyanate groups can be carried out in the same manner as described above, except that the blocking agent is used so that all of the isocyanate groups can be blocked.

In addition, N formed by blocking all isocyanate groups
The alkanolamine to be reacted with the glycidyl group in the GO polymer and its reaction conditions can also be carried out in the same manner as described above.

In the self-curing resin (B), if the amounts of pro-tsukiisocyanate groups and hydroxyl groups are made equal, the degree of crosslinking as a self-crosslinking coating film will be the highest, but when used in paints and adhesives, the degree of crosslinking will be the highest. , It is preferable that one of the functional groups is in excess in consideration of adhesion between layers, etc., and specifically, the hydroxyl value (II1gKO11/g) is 20 to 250,
Isocyanate group value (g/10100O is 15-250
A suitable amine value (+ngKOH/g) of 25 to 100 is suitable.

The self-curing resin (C) is produced by blocking all the isocyanate groups in the NGO type O polymer skeleton, and then reacting the glycidyl groups with primary to tertiary amines to form secondary to tertiary amino groups or quaternary amino groups. This is a self-curing resin characterized by introducing an ammonium base, a blocked isocyanate group, and a hydroxyl group.

The method for blocking all the isocyanate groups in the NGO polymer can be carried out in the same manner as in the case of resin (B) above.

As the primary to tertiary amine reacted with the glycidyl group, the following examples are preferable.

Primary or secondary amines include ammonia; lower alkyl amines such as methylamine, ethylamine,
Isopropylamine, n-butylamine, dimethylamine, diethylamine, diisopropylamine, di-n-
butylamine, etc.; alicyclic amines, such as cyclohexylamine; heterocyclic amines, such as morpholine, pyridine, etc.; examples of tertiary amines include trialkylamines, such as trimethylamine, triethylamine,
triisopropylamine, tri-n-propylamine,
Tri-n-butylamine; N-alkylmorpholine, such as N-methylmorpholine, N-ethylmorpholine; N
- dialkylalkanolamines, such as N,N-dimethylethanolamine, amine, N-diethylethanolamine; and mixtures of two or more thereof. Among these, it is preferable to use secondary or tertiary amines.

Although it is preferable to react the amine with all the glycidyl groups, it is acceptable if unreacted glycidyl groups remain. When an amine reacts with a glycidyl group, the ring opens and a hydroxyl group and a secondary to tertiary amino group or a quaternary ammonium base are generated.

In the self-curing resin (C), if the amounts of blocked isocyanate groups and hydroxyl groups are equal, the degree of crosslinking as a self-crosslinking coating film will be the highest, but when used in paints and adhesives, It is preferable that either one of the functional groups is in excess in consideration of the adhesion with the
It is suitable that the hydroxyl value (mgKOH/g) is 20 to 250, the isocyanate value (g/10100O is 15 to 250), and the amine value (■KOH/g) is 25 to 100.

The self-curing resin of the present invention has one or more blocked isocyanate groups, hydroxyl groups, secondary to tertiary amino groups and/or quaternary ammonium bases in one molecule, and when heated, the blocking agent It dissociates to regenerate isocyanate groups, which react with the hydroxyl groups to three-dimensionally self-crosslink and cure. The heating temperature is not particularly limited and may be any temperature at which the blocking agent dissociates, specifically 80°C.
The above is preferable. Therefore, the resin is stable at room temperature and does not self-cure.

Further, the self-curing resin of the present invention can be used after being dissolved or dispersed in an organic solvent. In addition, since it has a 2.tertiary amino group and/or a quaternary ammonium base in its molecule, the 2.tertiary amino group can be dissolved in water or It becomes dispersible and can be used as an aqueous solution (an organic solvent may also be present). A quaternary ammonium base is a tertiary ammonium base.
It can be produced by reacting a glycidyl group with a glycidyl group and then neutralizing it with the acid component described above, which is soluble or dispersible in water.

The self-curing resin is used in paints, adhesives, and the like.

For use in paints, pigments, fillers, surface conditioners, deterioration inhibitors, etc. may be added as necessary, and the paints can be used as molding paints. Additionally, polyols (e.g. acrylic resins,
Polyester resins, fluororesins), reactive diluents, and crosslinking agents (for example, melamine plasters, blocked isocyanates, epoxy systems, polybasic acid systems, alkoxysilane systems, etc.) can also be combined. Also, various curing catalysts may be used.

Paints, adhesives, and the like made of these materials are cured at a temperature of 50 to 200°C, preferably 80 to 150°C, to provide a three-dimensional crosslinked product.

Regarding the NGO polymer of the present invention, since no polymerizable monomer having active hydrogen or a solvent is used in the polymerization reaction system of the NGO monomer, gelation does not occur at all. In addition, in the present invention, since the blocking agent is reacted with the NCO polymer, the blocking agent only needs to be heated to the temperature required to react with the isocyanate group. It is advantageous for low-temperature curing because it can block isocyanate groups without being heated to high temperatures (approximately 100°C or less, does not cause any coloring, and dissociates at low temperatures (approximately 100°C or less). Even if the blocking agent is used at a high temperature, the reaction between the blocking agent and the NCO polymer is easily carried out and no gelation occurs. Because of this, it can be easily made water-based and can also be used as a cationic electrodeposition paint.

EXAMPLES Hereinafter, the present invention will be further explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto in any way.

In addition, [part] and [%] in Examples and Comparative Examples
As a general rule, it is based on heavy ■.

Example 1 30 parts of methyl cellosolve acetate was placed in a reactor equipped with a stirrer, a reflux condenser, and a thermometer, heated and maintained at 130°C, and 50 parts of m-isopropenyl-α,α'-dimethylbenzyl isocyanate was added. , 30 parts of n-butyl methacrylate, 8 parts of 2-ethylhexyl methacrylate, 12 parts of glycidyl methacrylate, and 3 parts of t-butyl peroxyisopropyl carbonate (manufactured by Gunpowder Axie)
．． 5 parts of the mixture were added dropwise over 3 hours.

Then, a mixed solution consisting of 5 parts of methyl ethyl ketone and 1.0 parts of t-butylperoxyisopropyl carbonate was added dropwise over 1 hour, and after further aging for 1 hour,
NC having a number average molecular weight of about 6500 when cooled to 0°C
A solution of O polymer was obtained.

To this polymer solution was added dropwise 21.6 parts of methyl ethyl ketone oxime over 15 minutes while stirring at 80°C, aged for 2 hours, and then 8.9 parts of jetanolamine was added dropwise over 15 minutes to The reaction was completed by aging at °C for 30 minutes [Self-curing resin (B)].

Neutralize by adding 5.0 parts of acetic acid, then add 6 parts of ion-exchanged water.
5 parts were added with stirring.

The obtained resin liquid was a slightly yellowish fine particle dispersion liquid. The Gardner viscosity was P, and no thickening was observed even after storage at 30° C. for one month.

The resin has a hydroxyl value of 94, 8 mgKOH/1
g Resin, isocyanate group value 104.4g/1000
g resin, amine value is 47.4mgKO! 'l/1 g resin.

Example 2 Under the same conditions as Example 1, 21.6 parts of methyl ethyl ketone oxime was added dropwise to the NCO polymer solution of Example 1 over 15 minutes, and the solution was aged for 2 hours. Then, 3.7 parts N, N
- dimethylethanolamine was added dropwise over 15 minutes, and
The reaction was completed by aging at 0°C for 2 hours. Acetic acid 2.5
3 parts were added to neutralize it, and then 65 parts of ion-exchanged water was added with stirring [self-curing resin (C)].

The resulting liquid was a slightly bluish, almost transparent dispersion.

Hydroxyl value 23. 7mgKO)l/1g resin, isocyanate group value 104.4g/1000g resin, amine value 23. It was 3 mg KOR/1 g resin.

Example 3 While stirring the NCO polymer solution obtained in Example 1 at 80°C, 16.23 parts of methyl ethyl ketone oxime was added dropwise over 15 minutes, aged for 2 hours, and then 15.
43 parts of jetanolamine was added dropwise over 15 minutes,
The reaction was completed by aging at 80° C. for 30 minutes.

8.82 parts of acetic acid was added to neutralize it, and then 65 parts of ion-exchanged water was added with stirring [Self-curing resin (A)]
.

The obtained resin liquid was a slightly yellowish fine particle dispersion liquid. The Gardner viscosity was P, and no thickening was observed even after storage at 30° C. for one month.

The resin has a hydroxyl value of 164.9 KO■/1 g resin,
The isocyanate value was 78.3 g/1000 g resin, and the amine value was 47.4 mg KOH/1 g resin.

Comparative Example 1 65 parts of methyl ethyl ketone was placed in a reactor equipped with a stirrer, a reflux condenser, and a thermometer, heated and maintained at 80°C,
20 parts of 2-isocyanate ethyl methacrylate, 15 parts of styrene, 22 parts of n-butyl methacrylate, 15 parts of 2-hydroxyethyl acrylate, 20 parts of 2-ethylhexyl acrylate, 8 parts of dimethylaminoethyl methacrylate, and azobis α,γ-dimethylvalero. A mixture of 2.5 parts of nitrile was added dropwise over 3 hours in an attempt to polymerize, but gelation occurred 30 minutes after the dropwise addition was started.

Comparative Example 2 In Example 1, 2-(methylamino)ethanol was added to the NGO polymer solution before adding methyl ethyl ketone oxime, and gelation occurred after 1 hour.

Performance test results The storage stability of the systems in which 0.2 parts of dibutyltin silaurylate was added as a curing catalyst per 100 parts of resin solid content to each resin liquid of Examples 1 to 3, and the system in which it was not added, and the storage stability of the systems in which these liquids were applied to a tin plate. The gel fraction was measured after coating to a dry film thickness of about 60 μm and baking at 120° C. and 140° C. for 30 minutes.

The results are shown in Table 1.

In Table 1, regarding storage stability, the increase in viscosity after storage at 30°C for one month was higher than that before storage using a Gardner viscometer (
20° C.), it was considered good if there were 2 or less. Further, the gel fraction was measured by extraction using acetone at a reflux temperature for 7 hours.

(that's all)

Claims (4)

[Claims] (1) A part of the isocyanate groups in the polymer skeleton having a number average molecular weight of 500 to 50,000 and having a glycidyl group and two or more isocyanate groups in one molecule are blocked, and then the glycidyl groups and the remaining end blocks are blocked. A self-curing resin characterized in that a blocked isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base, and a hydroxyl group are introduced into one molecule by reacting an isocyanate group with an alkanolamine. (2) Block all of the isocyanate groups in the polymer skeleton with a number average molecular weight of 500 to 50,000 and have a glycidyl group and two or more isocyanate groups in one molecule, and then react the glycidyl groups with an alkanolamine. A self-curing resin characterized in that a blocked isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base, and a hydroxyl group are introduced into one molecule. (3) Block all of the isocyanate groups in the polymer skeleton with a number average molecular weight of 500 to 50,000 and have a glycidyl group and two or more isocyanate groups in one molecule, and then block the glycidyl groups with primary to tertiary amines. React 1
A self-curing resin characterized by having a blocked isocyanate group, a secondary to tertiary amino group or a quaternary ammonium base, and a hydroxyl group introduced into the molecule. (4) An aqueous self-curing resin obtained by neutralizing the amino groups in the self-curing resin according to any one of claims (1) to (3) with an acid component.