JPH03119076A - Self-crosslinking high-rigidity resin composition for electro-deposition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent coating film properties such as yellowing resistance, chemical resistance and adhesion property in addition to high rigidity by polymerizing a polyblocked isocyanate and a hydroxy ester of an alpha,beta-ethylenic unsaturated monocarboxylic acid, etc. CONSTITUTION:The objective composition having a molecular weight of 3,000-30,000 and having a polyblocked isocyanate group on a side chain group is produced by polymerizing (A) 1-50 pts.wt. of a radical-polymerizable polyblocked isocyanate having one alpha,beta-ethylenic unsaturated group and 2 or 3 blocked isocyanate groups in one molecule and (B) 1-50 pts.wt. of at least one kind of compound selected from hydroxy ester of an alpha,beta-ethylenic unsaturated monocarboxylic acid, a caprolactone addition reaction product of an alpha,beta- ethylenic unsaturated monocarboxylic acid and an addition reaction product of an epoxy compound and an alpha,beta-ethylenic unsaturated monocarboxylic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a self-crosslinking highly rigid electrodeposition resin composition. More specifically, the present invention relates to a self-crosslinking, highly rigid electrodeposition resin composition that not only has high rigidity but also has excellent coating properties such as yellowing resistance, chemical resistance, and adhesion.

Conventional techniques for electrodeposition coating are described in the literature (e.g. J, Oil Co1. Ch.
em.

^3soc1. LL, 482 (1980)), a conductive coating material is immersed in a coating film-forming substance dispersed in water and given an electric charge, electricity is applied, and after electrocoagulation,
This is a painting method that involves baking. In this way, since water is used as a medium, there is little risk of fire, and it is a through-layer coating method that provides excellent uniformity of the coating film and low cost.

However, melamine resins and amino resins, which are widely used as crosslinking agents in such electrodeposition paints, may cause condensation reactions between the crosslinkers at room temperature, resulting in a decrease in the stability of the electrodeposition paints over time. Uniform electrodeposition of objects to be coated has become a problem. In addition, from the viewpoint of physical properties, electrodeposition paints using such crosslinking agents have poor coating performance such as light resistance and alkali resistance, and do not necessarily show fully satisfactory results. Since melamine resins are used as additives to resins, they have the disadvantage of poor compatibility and difficulty in making them water-based, since they have a relatively high molecular weight. Also, the baking temperature is relatively high, which is disadvantageous from the point of view of energy costs.

As a means to solve these problems, a method has been proposed in which a blocked isocyanate is included as a side chain group in an acrylic polymer and the polymer is liquefied. For example, JP-A-63-46203, JP-A-1-1134701
No. 3470 and P4399256 disclose copolymerization of acylated isocyanates, and JP-A-63-2037
3 and JP-A-63-18672286722 disclose the introduction of impropenyl α,α-dimethylbenzyl isocyanate, and JP-A-61-4720 and JP-A-62-74969 disclose the introduction of isophorone diisocyanate. You can see the disclosure of the body.

Problem to be Solved by the Invention However, with these methods - liquefaction can be achieved;
Although the stability over time is improved, since the number of crosslinking points is limited to one per molecule, it is insufficient as an electrodeposition resin that requires high physical strength. In addition, in order to obtain high rigidity, it is necessary to increase the charging ratio of blocked isocyanate, which results in an increase in the glass transition point of the polymer, resulting in poor smoothness during baking and a tendency for poor appearance. have.

It is therefore an object of the present invention to significantly improve various physical properties, in particular the stiffness, of polymers comprising such prior art radically polymerizable monoblocked isocyanates;
Another object of the present invention is to provide a self-crosslinkable, highly rigid electrodeposition resin composition that has good adhesion and surpasses the baking temperature and light resistance of conventional crosslinking agents for melamine resins.

Means for Solving the Problems In view of the above-mentioned circumstances, the present inventors have developed a method that fully satisfies physical properties such as stability over time, low-temperature curability, and high rigidity, and
- As a result of intensive research on liquid electrodeposition resin compositions, we found that (a) a specific radically polymerizable polyblocked isocyanate, (b) a hydroxy ester of α, β-ethylenically unsaturated monocarboxylic acid, At least one of the caprolactone addition reaction product of α,β-ethylenically unsaturated monocarboxylic acid or the addition reaction product of epoxy compound and α,β-ethylenically unsaturated monocarboxylic acid, (c) optionally, Tertiary amino group-containing vinyl monomer (d) If necessary, α,β-ethylenically unsaturated monocarboxylic acid,
(e) α, if necessary.

A composition containing a resin obtained by copolymerizing at least one of an alkyl ester of a β-ethylenically unsaturated monocarboxylic acid or an α,β-ethylenically unsaturated compound can provide a coating film with high rigidity and a moderate Based on this knowledge, we have completed the present invention.

That is, the present invention provides (a) one α, β in one molecule;
- 1 to 50 parts by weight of a radically polymerizable polyblocked isocyanate having an ethylenically unsaturated group and two or three blocked isocyanate groups, and (b) (b1) α,β-ethylene (b2) caprolactone addition reaction product of α, β-ethylenically unsaturated monocarboxylic acid, or (b3) epoxy compound and α, β-ethylenically unsaturated monocarboxylic acid. 1 to 50 parts by weight of at least one of the addition reaction products with the compound having an average molecular weight of 3000 to 300 and having a polyblocked isocyanate group as a side chain group.
This is a self-crosslinking, highly rigid electrodeposition resin composition characterized in that it contains a product controlled to have 0.00 as an active ingredient.

Further, in the present invention, the copolymerization is carried out by containing 1 to 20 parts by weight of (c) a tertiary amino group-containing vinyl monomer, and the average molecular weight of the copolymerization having a polyblocked isocyanate group as a side chain group is 3000. This is a self-crosslinking high-rigidity electrodeposition resin composition, characterized in that it is a composition containing as an active ingredient a product controlled to have a hardness of 30,000 to 30,000.

Further, in the present invention, the copolymerization may include (d) a, β
- A composition containing as an active ingredient a product containing 1 to 20 parts by weight of an ethylenically unsaturated monocarboxylic acid and having a polyblocked isocyanate group as a side chain group and having an average molecular weight controlled to 3,000 to 30,000. This is a self-crosslinking highly rigid electrodeposition resin composition characterized by the following.

Further, in the present invention, the copolymerization is carried out as necessary (e) (e1).
Polyblocked isocyanate group in the side chain containing 1 to 50 parts by weight of at least one of α,β-ethylenically unsaturated monocarboxylic acid alkyl ester or (e2) α,β-ethylenically unsaturated compound This is a self-crosslinking highly rigid electrodeposition resin composition characterized by containing as an active ingredient a product having an average molecular weight of 3,000 to 30,000.

The above-mentioned (a) polyblocked isocyanate capable of radical polymerization, which has one α, β-engineered tylenically unsaturated group and two or three blocked isocyanate groups in one molecule, It is an addition reaction product of a monosubstituted triol of α,β-ethylenically unsaturated monocarboxylic acid and a half-blocked isocyanate, and is represented by the formula (1), CHx ORz R, -C-OR,...・(I) CH20R4 (wherein, R1 represents hydrogen or a methyl group, and R21R3
. It is linked to the triol residue via a bond. ) Or, it is a derivative having two or three half-blocked isocyanates for a reaction product of dimethylolpropionic acid and a glycidylated metal of α,β-ethylenically unsaturated monocarboxylic acid, and has the formula (I[ ).

CH*ORs CH,OR,0RI (wherein, at least two groups of Rs, Rs, and Rt are half esters of an alicyclic diisocyanate group or an aliphatic diisocyanate group and a blocking agent, and dimethylol Combines with propionic acid residue, R
, represents an acryloyloxy group, a methacryloyl group, or an aryloyl group) Specifically, -α,β-ethylenically unsaturated monocarboxylic acid, which is the starting material of the addition reaction product represented by formula (1). Examples of monosubstituted triols include glycerin monoacrylate, glycerin monomethacrylate, glycerin monoallyl ether, trimethylolpropane monoacrylate, trimethylolpropane monomethacrylate, and trimethylolpropane monoallyl ether.

In addition, the compound represented by -8 formula (II) uses dimethylolpropionic acid as a starting material, and combines it with a glycidyl compound of α,β-ethylenically unsaturated carboxylic acid or an α,β-ethylenically unsaturated glycidyl ether compound. It is obtained by reacting an intermediate obtained by an addition reaction with a half-blocked product of an alicyclic diisocyanate or an aliphatic diisocyanate. Specifically, examples of glycidyl compounds of α,β-ethylenically unsaturated carboxylic acids include glycidyl acrylate, glycidyl methacrylate, etc., and examples of α,β-ethylenically unsaturated glycidyl ether compounds include allyl glycidyl ether. It will be done.

In general formula (1), two types among R2, R3, R,
In the general formula (■), two or more of Rs, Ft, and Rt represent a half ester of an aliphatic or alicyclic diisocyanate and a blocking agent.

Specific examples of the diisocyanate include bis(isocyanatomethyl)cyclohexane, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

Blocking agents used to block one side of the diisocyanate include, for example, phenol-based, lactam-based, active methylene-based, alcohol-based, mercaptan-based, urea-based, imidazole-based, oxime-based, hydroxamic acid-based, sulfite-based, or amine-based blocking agents. Examples include agents.

Particularly preferred are phenol-based, active methylene-based, hydroxamic acid-based, and oxime-based.

Specific examples of these blocking agents include the following.

(1) Phenolic blocking agents phenol, cresol, xylenol, nitrophenol, thymol, butylphenol, in-10-bylphenol, nonylphenol, octylphenol, chlorophenol, resorcinol, etc.

(2) Lactam-based blocking agents ε-caprolactam, δ-valerolactam, β-propiolactam, etc.

(3) Active methylene blocking agents such as acetylacetone, methyl acetoacetate, ethyl acetoacetate, dimethyl malonate, diethyl malonate, etc.

(4) Alcohol-based blocking agents methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, lauryl alcohol, ethylene glycol monomethyl ether,
Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, benzyl alcohol, methoxymethanol, furfuryl alcohol, cyclohexanol, trifluoro alcohol, etc.

(5) Mercaptan-based blocking agent butyl mercaptan, thiophenol, etc.

(6) Urea-based blocking agent Urea, thiourea, ethylene urea, etc.

(7) Imidazole blocking agent imidazole, 2-ethylimidazole, 2-methyl-
4-ethylimidazole and the like.

(8) Oxime-based blocking agents such as formamide oxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, isopropenyl oxime, quinone oxime, cyclohexanone oxime, benzophenone oxime, etc.

(9) Hydroxamic acid blocking agents such as phenylcarbamoyl and benzylbenzohydroxamate.

(10) Sulfite-based blocking agent Sodium bisulfite, potassium bisulfite, etc.

(11) Amine-based blocking agents such as dimethylamine, diethylamine, dibutylamine, monoethanolamine, jetanolamine, etc.

Half-blocking of blocking agent and diisocyanate is
The blocking agent and excess diisocyanate are reacted, and after the addition reaction product is produced, the excess diisocyanate is removed by suction. In addition, depending on the type of diisocyanate used, the difference in addition reaction rate may be used. This half-block formation is carried out, if necessary, in a solvent that does not inhibit the addition reaction between isocyanate groups and hydroxyl groups. Blocking agents are often liquid at room temperature and can themselves serve as blocking solvents, but include aromatic agents such as toluene and xylene, acetone,
The reaction may be carried out in a ketone solvent such as methyl ethyl ketone, or an ester solvent such as ethyl acetate or butyl acetate. These may be used alone or in mixtures.

This reaction is preferably carried out under a known catalyst such as an organotin, tertiary amine, or phosphine.

Specifically, the (b1) hydroxy ester of α,β-ethylenically unsaturated monocarboxylic acid used in the present invention includes hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and (meth)acrylic acid. Examples include hydroxybutyl.

Specific examples of the (b2) caprolactone addition reaction product of α,β-ethylenically unsaturated monocarboxylic acid used in the present invention include addition reaction products of (meth)acrylic acid, droxyethyl, and caprolactone. .

In addition, (b3) the epoxy compound used in the present invention and α
, (3-chloropropyl-2-hydroxy)(meth)acrylate, (3-butoxy-2-
hydroxy)propyl (meth)acrylate, (3-phenyloxy-2-hydroxy)propyl (meth)acrylate, (3-butyloxy-2-hydroxy)propyl (meth)acrylate? -, a reaction product of persatic acid glycidyl ester and (meth)acrylic acid, a reaction product of lauryl glycidyl ether and (meth)acrylic acid,
Examples include reaction products of allyl glycidyl ether and (meth)acrylic acid.

Specifically, the (c) tertiary amine group-containing vinyl monomer used as necessary for the purpose of imparting electrodepositability, flexibility, improved reactivity, and adhesion to the resin composition of the present invention includes:
Examples include dimethylamine methyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diaminopropyl (meth)acrylate, vinylpyridine, and vinylimidazole.

(d) α5β-ethylenically unsaturated monocarboxylic acid, which is used as necessary for the purpose of imparting electrodeposition, rigidity, and adhesion to the resin composition of the present invention, specifically includes (meth)
Acrylic acid, crotonic acid, itaconic acid, half ester of droxyethyl (meth)acrylate and succinic anhydride, half ester of hydroxyethyl (meth)acrylate and maleic anhydride, hydroxyethyl (meth)acrylate Half ester of and phthalic anhydride, (
Half ester of hydroxyethyl meth)acrylate and tetrahydrophthalic anhydride, Half ester of hydroxyethyl (meth)acrylate and hexahydrophthalic anhydride, Hydroxyethyl (meth)acrylate and methyltetrahydro Examples include half esters of phthalic anhydride, half esters of hydroxyethyl (meth)acrylate and trimellitic anhydride, and half esters of hydroxyethyl (meth)acrylate and pyromellitic anhydride.

(e1) α is used as necessary for the purpose of imparting visibility and flow characteristics to the resin composition of the present invention.

Specifically, the β-ethylenically unsaturated monocarboxylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and (meth)acrylate. 2-ethylhexyl acid, lauryl (meth)acrylate, boronyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylate
Examples include cyclohexyl acrylate and phenoxyethyl (meth)acrylate.

Further, as (e2) α, β-ethylenically unsaturated compounds used as necessary for imparting rigidity and flow characteristics to the resin composition of the present invention, styrene, methylstyrene, vinylcarbazole, etc. are specifically mentioned. Can be mentioned.

The composition of the resin composition of the present invention includes 1 to 50 parts by weight of the radically polymerizable polyblocked isocyanate (a);
Preferably it is 10 to 30 parts by weight. This range is preferable in terms of the balance between crosslink density and elasticity of the resin composition of the present invention. If it is too low, the crosslink density will be low and chemical properties such as solvent resistance will be impaired, and if it is too high, brittleness will occur and the resistance will be reduced. This results in a coating film with poor impact resistance, which is different from the highly rigid and highly elastic coating film of the present invention.

(b) hydroxy ester of α2β-ethylenically unsaturated monocarboxylic acid, which is an essential component of the resin composition of the present invention;
At least one of the caprolactone addition reaction product of α,β-ethylenically unsaturated monocarboxylic acid and the addition reaction product of epoxy compound and α,β-unsaturated monocarboxylic acid is 1-
The amount is 50 parts by weight, preferably 10 to 30 parts by weight. Hydroxyl groups contribute to adhesion to the base material and crosslinking components, so
Within this range, it is preferable to design the amount to be equivalent to or slightly in excess of the isocyanate group; too much hydroxyl group is undesirable because it increases the hydrophilicity of the coating film and increases the water absorption rate.

The amount of the tertiary amino group-containing vinyl monomer (c) used as needed in the resin composition of the present invention is 1 to 20 parts by weight, preferably 2 to 10 parts by weight.

If it is too small, the water dispersibility and adhesion of the coating film will be poor in the case of cationic electrodeposition, and if it is too large, the weather resistance will be poor, which is not preferable.

α of (d) used as necessary in the resin composition of the present invention
, β-ethylenically unsaturated monocarboxylic acid in an amount of 1 to 20 parts by weight, preferably 2 to 8 parts by weight. If it is too small, the water dispersibility and adhesion of the coating film will be poor in anionic electrodeposition, and if it is too large, the water resistance and alkali resistance will be poor.

α of (e) used as necessary in the resin composition of the present invention
, an alkyl ester of a β-ethylenically unsaturated monocarboxylic acid, and an α,β-ethylenically unsaturated compound in an amount of 1 to 50 parts by weight. If it is too small, it will be difficult to adjust the glass transition point of the coating, and the smoothness of the appearance will be lost.
It seriously impairs the aesthetic appearance. If the amount is too large, the number of crosslinking points will decrease, making it impossible to achieve the high rigidity of the present invention.

The resin composition of the present invention is a copolymer obtained by copolymerizing the above (a) and (b) and, if necessary, (c), (d) or (e) by a known polymerization method. , is a self-crosslinking electrodeposition resin composition having high rigidity with an average molecular weight controlled to 3,000 to 30,000 and having a polyblocked isocyanate group as a side chain group in the copolymer.

During polymerization, known additives such as polymerization regulators,
Antioxidants, solvents, radical generators, inert gases, etc. are used as appropriate.

The resulting copolymer neutralizes its acidic or basic groups and provides water dispersibility necessary for electrodeposition.

When acidic groups are introduced into the copolymer, neutralization is carried out with a base, and when basic groups are introduced, neutralization is carried out with an acid. Examples of acids necessary for neutralization include organic acids such as acetic acid, formic acid, propionic acid, and lactic acid, and inorganic acids such as sulfuric acid and phosphoric acid. As the base, amines such as methylamine, ethylamine, and triethylamine, alkanolamines such as monoethanolamine and jetanolamine, or inorganic bases such as sodium hydroxide and potassium hydroxide are used. The amount of neutralization is an important factor that determines the particle size of copolymer micelles, and is usually 0.
A neutralizing amount of 5 to 1.2 equivalents is used.

Aqueous dispersion is carried out according to a known method. For example, after neutralizing the resin composition, ion-exchanged water may be gradually added thereto to form an aqueous dispersion, or the resin composition may be added to ion-exchanged water to form an aqueous dispersion. In the compound represented by (II), Rs, which is a half ester of a terminal isocyanate group and a blocking agent, R
s, R? If alkanolamines are used as any one of the blocking agents, a basic group is introduced into the compound represented by formula (II), and in this case, the tertiary amino group-containing vinyl shown in (3) It is possible to obtain a water-dispersible resin composition without using a monomer. In this case, the restrictions on the content of basic groups and the amount of neutralization are in accordance with the above-mentioned regulations.

When the resin composition of the present invention is made into an aqueous dispersion, the following various additives are added as necessary. i.e. thickeners,
Surface active agents, surfactants, ultraviolet absorbers, corrosion inhibitors,
These include film-forming inhibitors, anti-sagging agents, lubricants, antistatic agents, crater-forming inhibitors, plasticizers, and antifoaming agents.

Copolymers other than those of the present invention may be added to this aqueous dispersion as necessary to improve electrodeposition characteristics and flow characteristics. Examples of copolymers include acrylic resin, alkyd resin, and polyester resin. , polyamide resins, and various cellulose derivatives.

Further, an organic or inorganic filler may be added to this aqueous dispersion as necessary. Examples of the filler include MMA bead polymer, styrene bead polymer, urethane polymer, calcium carbonate, silica, glass particles, talc,
Examples include kaolin.

Further, pigments or dyes may be added to this aqueous dispersion as necessary. Dyes and pigments include azo derivatives, azomethine derivatives, phthalocyanine derivatives, titanium dioxide, lithopone, barium sulfate, zinc oxide, carbon black, etc. can be mentioned.

Furthermore, this aqueous dispersion contains a reaction catalyst between isocyanate groups and active hydrogen, if necessary. Examples of the reaction catalyst include tin compounds, lead compounds, tertiary amines, phosphonium salts, metal salts of organic carboxylic acids, zinc compounds, etc., with tin compounds being preferred.
For example, Te1-butyltin, tributyltin chloride, tributyltin-〇-felt, tributyltin cyanate, tin octylate, tin oleate, dibutyltin silaurylate, dibutyltin di(2-ethylhexoate), tetra-
Examples include n-butyl-1,3-diacetyloxydistanoxane. These catalysts are used alone or as a mixture of two or more. The amount of the zero-reaction catalyst varies depending on the type, but it is usually 0.
．． A sufficient catalytic effect can be obtained with 0.01 to 1 part by weight.

In the present invention, charging differs depending on the ratio of the tertiary amino group-containing vinyl polymer (c) and the α,β-ethylenically unsaturated monocarboxylic acid (d) to the resin composition. That is, when the amino group component (c) is large, the resin becomes cationic, and when the carboxylic acid component (d) is large, the resin becomes anionic.

Cationic components are effective in accelerating thermosetting of resins and are preferable for improving reactivity during cationic electrodeposition, but in the case of anionic electrodeposition, excessive anionic components tend to inhibit curing, and are therefore preferable. If the acid value is within the range of 50 to 10, curing will not be inhibited.

The above-mentioned water-dispersible resins are stable in water even at resin concentrations of 1 to 70%. High solidity is advantageous for storage and transportation, and the concentration may be adjusted to this level, but in the past it was desirable to use it within a range of 5 to 15 parts by weight.

The resin composition of the present invention is a two-dimensional polymer before curing by heating, but after curing, it forms a three-dimensional bridge by urethanization of isocyanate groups and hydroxyl groups, and easily exhibits high rigidity. In this way, three-dimensional cross-building utilizes urethanization of isocyanate groups and hydroxyl groups, so the ratio of isocyanate equivalent to hydroxyl group has a significant effect on the rigidity and solvent resistance of the coating film. Normally, NC01
The 0H equivalent ratio is carried out within the range of 1.0 to 0.2, preferably in the range of 1.0 to 0.7. As a hydroxyl group, -
Grade or second grade or first and second grade are used. Although the rate of addition reaction is slower in the secondary type, there is often no particular problem.

The blocking agent of the present invention described above is not limited to the same type of blocking agent in the same molecule. In other words, if blocking agents with different dissociation temperatures are used, the curing temperature can be raised in stages to improve anti-sagging properties, It is also possible to improve the appearance. This method is also effective in suppressing residual stress in the coating film due to detachment of the blocking agent. In this case, the desorption temperature difference of the blocking agent needs to be about 40'C.

Function and Effect As mentioned above, the synthesized resin composition of the present invention having a polyblocked isocyanate group in its side chain easily dissociates the blocking agent and releases the reactive isocyanate group when a predetermined temperature is reached. Reproduce.

The regenerated isocyanate group immediately forms a bridge with the active hydrogen in the acrylic polymer of the resin composition, and the acrylic polymer is cross-linked via the urethane bond. Urethane bonds have strong intermolecular li concentration and a high ability to form intermolecular hydrogen bonds, increasing rigidity and adhesion to the base material. Moreover, the resin composition of the present invention has two or three blocked isocyanate groups, has many crosslinking points, and has a high density of crosslinks. That is, since two to three meshes are formed, high rigidity is achieved.

The present invention relates to a one-component acrylic emulsion of polyblocked isocyanate, and according to the present invention, a resin composition having high rigidity, excellent yellowing resistance, chemical resistance, and adhesion can be obtained. . This resin composition is
It is useful as water-based paints, automotive paints, electrodeposition paints, and engineering plastics, and is particularly suitable as electrodeposition paints for decorative metals that require good appearance and hardness.

Example The present invention will be explained in more detail by way of examples.

However, the present invention is not limited only to the examples.

(Example 1) 167 g of reaction product of glycerin monomethacrylate and acetoxime half-blocked product of hexamethylene diisocyanate, 52 g of n-butyl acrylate, 20 g of 2-ethylhexyl acrylate, 1 methyl methacrylate
16 g, styrene 60 g, hydroxyethyl methacrylate 80 g, N,N-dimethylaminoethyl methacrylate 32 g, 2,2'-azobis(2
9 g of 4-dimethylvaleronitrile) was dissolved in 100 g of isopropyl alcohol and added dropwise over 2 hours into a flask filled with 206 g of isopropyl alcohol. 1. During polymerization, nitrogen was bubbled, and the polymerization temperature was 90 to 95°C.
After completion of the 0 drop addition, aged for 2 hours to obtain a copolymer with an average molecular weight of 12,000. 11 g of acetic acid was added to the obtained copolymer with a polymerization rate of 96%, and after neutralization, water was added. The resin content was adjusted to 10%. The conditioning solution showed a uniform aqueous dispersion.

(Example 2) 181 g of reaction product of glycerin monoallyl ether and methyl acetoacetate half-blocked product of hexamethylene diisocyanate, 52 g of n-butyl acrylate, 2-
20 g of ethylhexyl acrylate, 112 g of methyl methacrylate, 60 g of styrene, 80 g of hydroxyethyl methacrylate, 32 g of N,N-dimethylaminoethyl methacrylate, 9 g of 2,2'-azobis(2,4-dimethylvaleronitrile) and 10 g of isopropyl alcohol.
During the polymerization, which was dissolved in 0.0 g and dropped into a flask filled with 206 g of isopropyl alcohol over a period of 2 hours, nitrogen gas was bubbled and the polymerization temperature was maintained at 90 to 95°C. After completion of the dropwise addition, aging was performed for 2 hours, and the average molecular weight was 1300.
A uniform dispersion was obtained by adding 11 g of vinegar a to the resulting copolymer with a polymerization rate of 97%, and after neutralization, water was added thereto.

(Example 3) 19 g of a reaction product in which the reaction product of dimethylolpropionic acid and glycidyl methacrylate was trisubstituted with an acetoxime-blocked isophorone diisocyanate half-blocked product,
n-butyl acrylate 1.52 g, 2.2'-dimethylaminoethyl methacrylate 32 g, methyl methacrylate 86 g, styrene 60 g, hydroxyethyl methacrylate 80 g, alkyl vinyl ether having 12 carbon atoms 2
6. Polymerization rate of 96% was obtained by dissolving 9 g of 2.2'-azobis(2,4-dimethylvaleronitrile) in 100 g of isopropyl alcohol and dropping it into a flask filled with 206 g of isopropyl alcohol over a period of 2 hours. 16 g of lactic acid was added to the resulting copolymer, and after neutralization, water was added to obtain a uniform dispersion.

(Comparative Example 1) 184 g of completely blocked product of isocyanate ethyl methacrylate and methyl ethyl ketoxime, 22 g of n-butyl acrylate, 20 g of 2-ethylhexyl acrylate
g, 106 g of methyl methacrylate, 43 g of styrene, 120 g of hydroxyethyl methacrylate, 32 g of N,N-dimethylaminoethyl methacrylate, and 9 g of 2゜2'-azobis(2,4-dimethylvaleronitrile) as a polymerization initiator in 100 g of isopropyl alcohol. The solution was dissolved in 206 g of isopropyl alcohol and dropped into a flask filled with 206 g of isopropyl alcohol over a period of 2 hours. During the polymerization, nitrogen was bubbled and the polymerization temperature was maintained at 90 to 95°C. The polymerization rate was 9.
A copolymer having an average molecular weight of 8% and an average molecular weight of 113,000 was obtained. 16 g of lactic acid was added to the obtained copolymer to adjust the resin content to 10%.

(Comparative Example 2) 235 g of a compound obtained by addition-reacting 2-hydroxyethyl methacrylate to a half-blocked product of isophorone diisocyanate and ethyl acetoacetate, 18 g of n-butyl acrylate, 81 g of methyl methacrylate, and 6 g of styrene.
0g, N,N-dimethylaminoethyl methacrylate 3
2g, 2,2'-azobis(2,4-
Dissolve 9 g of dimethylvaleronitrile in 100 g of isopropyl alcohol, and dissolve 20 g of isopropyl alcohol.
The mixture was added dropwise into a flask filled with 6 g over a period of 2 hours.

The following conditions are based on Comparative Example 1.

Electrodeposition was performed using the 10% aqueous dispersions of Examples 1 to 3 under the following conditions.

0 surface treatment using brass as the cathode and a carbon plate as the anode, acrylate (product name, manufactured by Shimizu Co., Ltd.) treatment, and then connector (product name, manufactured by Shimizu Co., Ltd.) treatment, printed on 50■, Electrify for 1 minute, wash with water after electrodeposition, pre-dry for 20 minutes at 100℃, and then heat to 140℃
Baking was performed for 20 minutes. The film thickness was 20 μm.

The coated film after baking had a good appearance, with no pinholes or traces of gas leakage, and a transparent, smooth, and uniform coated film was obtained.

Note that the activator treatment is an activation step, and the connector treatment is a chromate treatment.

Examples 1 to 3 using the 10% aqueous dispersion of Comparative Example 1.2
Electrodeposition was performed in the same manner. The appearance of the obtained coating film was good, and the coating film was transparent and smooth.

Table 1 shows the test results of Examples 1 to 3 and Comparative Example 1.2.

(Margin below)

Claims (4)

[Claims] (1) (a) One molecule of polyblocked isocyanate capable of radical polymerization, which has one α,β-ethylenically unsaturated group and two or three blocked isocyanate groups in one molecule. ~50 parts by weight, and (b) (b1) hydroxy ester of α,β-ethylenically unsaturated monocarboxylic acid, (b2) caprolactone addition reaction product of α,β-ethylenically unsaturated monocarboxylic acid, or (b3 ) An average compound having a polyblocked isocyanate group as a side chain group, obtained by polymerizing 1 to 50 parts by weight of at least one addition reaction product of an epoxy compound and an α,β-ethylenically unsaturated monocarboxylic acid. Molecular weight is 3000-3000
1. A self-crosslinking highly rigid electrodeposition resin composition, characterized in that the composition contains as an active ingredient a product controlled to have a 0. (2) The self-crosslinkable highly rigid electrodeposition resin composition according to claim 1, wherein the copolymerization is further carried out by containing 1 to 20 parts by weight of (c) a tertiary amino group-containing vinyl monomer. thing. (3) The copolymerization further includes (d) α,β-ethylenically unsaturated monocarboxylic acid from 1 to
Claim 1, characterized in that it contains 20 parts by weight.
3. The self-crosslinking highly rigid electrodeposition resin composition according to item 1 or 2. (4) The copolymerization further includes at least one of (e) (e1) an alkyl ester of an α,β-ethylenically unsaturated monocarboxylic acid or (e2) an α,β-ethylenically unsaturated compound. Claim 1 characterized in that
3. The self-crosslinking highly rigid electrodeposition resin composition according to item 1, 2 or 3.