JPS5933630B2 - Electrodeposition paint and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel electrodeposition coating material and a method for producing the same.

In recent years, a method of forming an organic film on an electrical conductor by electrodeposition has attracted attention as an electrodeposition coating method, and water-soluble electrodeposition paints and water-dispersible electrodeposition paints have been developed for use in this coating method.
The above-mentioned water-soluble electrodeposition paint has a uniform deposited film and can be easily applied to small gaps, so it has good throwing power, or it can only obtain a film thickness of several tens of microns at most, so it is usually 100 microns or more. Most of them are unsuitable for electrical insulation applications, which require a film thickness of .

Therefore, water-dispersed electrodeposition paints, which are said to be able to theoretically obtain a desired film thickness, are considered promising for electrical insulation. Several types of water-dispersed electrodeposition paints are currently known, but at present no paint has been obtained that has excellent flexibility and adhesion, as well as satisfactory chemical resistance and voltage resistance. It is. The present inventors have conducted extensive research in view of the current situation, and have discovered that an epoxy resin modified with a polybutadiene compound can satisfy the above-mentioned characteristics as an electrodeposition coating, and have completed the present invention.

That is, the present invention uses a reaction product of hydroxypolybutadiene and a polybasic acid or anhydride thereof having a hydroxyl group at the end of the molecular chain or a side chain of the molecule, and an epoxy resin having two or more epoxy rings in the molecule. Electrodeposition coatings are based on polybutadiene-modified epoxy resin obtained by reacting the reaction product with hydroxypolybutadiene, which has a hydroxyl group at the end of the molecular chain or on the side chain of the molecule, and a polybasic acid or its anhydride. An epoxy resin having two or more epoxy rings is reacted to form a polybutadiene-modified epoxy resin, and then dissolved in an organic solvent and dispersed in water containing a surfactant and a volatile base. It is a method for producing electrodeposition paints in which the solvent and volatile base are distilled out of the system. The hydroxy polybutadiene used here includes 1/2 type added hydroxy polybutadiene, 1/4 type added hydroxy polybutadiene,
1, 2, 1, 4 type random addition hydroxypolybutadiene and their derivatives (butadiene with part of the double bond oxidized with oxygen, part of the double bond added with hydrogen or halogen atom) etc.), and the number average molecular weight preferably used is a liquid or solid one having a number average molecular weight of 200 to 5000.

If the number average molecular weight is less than 200, the mechanical properties will be poor, and if it is more than 5,000, water dispersibility will become difficult, which is not preferred. A typical commercially available example is NiSSO-P.
BGlOOOO,. G-2000,. G-3000 (manufactured by Nippon Soda, trade name) is mentioned.

The polybasic acid or its anhydride used herein can be used without any particular limitation, but preferred examples include maleic anhydride, phthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, Hexahydrophthalic anhydride, succinic anhydride, adipic acid, isophthalic acid,
These include acid-terminated polyester oligomers made of ethylene glycol and trimellitic anhydride, and acid-terminated polyester oligomers made of propylene glycol and isophthalic acid.

Furthermore, the epoxy resins used here include Epicoat 828 (epoxy equivalent weight 184-194), Epicoat 871 (epoxy equivalent weight 390-470), Epicoat 10
Bisphenol type epoxy resins such as 01 (epoxy equivalent: 450-500) (all manufactured by Ciel Chemical, trade names), Epicoat 152 (epoxy equivalent: 172-179),
Novolak-type epoxy resins such as Epicoat 154 (epoxy equivalent: 176 to 181) (all manufactured by Shinil Chemical Co., Ltd., trade names), Chitsonox 221 (epoxy equivalent: 131)
~145), Chitsonox 289 (epoxy equivalent weight 20
Alicyclic epoxy resins such as 5-222) (all manufactured by Chitsuso, trade names) can be used alone or in combination without any particular restrictions.

The electrodeposition paint of the present invention is obtained from the hydroxypolybutadiene and polybasic acid or its anhydride and has an acid value of 40 to
It is characterized in that a polybutadiene-modified epoxy resin having an acid value of 20 to 100 obtained by reacting a reaction product with an acid value of 300 to 100 is used as a main ingredient.
Next, manufacturing examples of the present invention will be described.

A hydroxy polybutadiene having a hydroxyl group at the end of the molecular chain or a side chain of the molecule and a polybasic acid or its anhydride are reacted until the acid value reaches 40 to 300, and this reaction product has two or more epoxy rings in the molecule. The so-called B before curing, which has an acid value of 20 to 100, is produced by reacting with an epoxy resin at 50 to 200°C in the absence of a solvent or in the presence of a solvent.
A stage polybutadiene-modified epoxy resin is obtained, which is dissolved in a solvent that mostly has a temperature below 100°C or which can evaporate at a temperature below 100°C by coexistence with water, and then a surfactant. and water containing a small amount of a volatile base such as ammonia, stirred at room temperature to about 80°C, and further blown with nitrogen gas to distill off part or all of the solvent and the volatile base, Stable and insoluble water-dispersed particles (electrodeposition paint) are produced.

As mentioned above, the solvent used in the above production dissolves the polybutadiene-modified epoxy resin, and most of the solvent has a temperature of 100°C or lower, or can evaporate at 100°C or lower due to coexistence with water. If necessary, for example, methyl nityl ketone, dioxane, acetone, ethylene dichloride, xylene, ethyl cellosolve, etc. can be used alone or in combination. It is also effective to use a small amount of a high-point solvent such as N-methylpyrrolidone to promote the dissolving power. As the surfactant, anionic surfactants, cationic surfactants, and nonionic surfactants can be used alone or in combination. Examples include sodium lauryl sulfate, sodium lauryl sulfate, sodium alkylbenzene sulfonate, sodium octylsulfosuccinate, polyoxyethylene alkyl ether, polyoxylauryl ether, etc. Anionic activators are preferred from the viewpoint of later electrodeposition properties. suitable.

Furthermore, as volatile bases, ammonia, trimethylamine, monoethanolamine, etc. can be used, and
It is necessary that the substance be volatile enough to be largely removed by the following heating.

Details will be explained below using examples. Example 1 A reaction vessel equipped with a thermometer, a stirrer and a gas guide tube was
1,2 addition polybutadiene (NiSSO-PB.G-1) with a number average molecular weight of 1300 and having hydroxyl groups at both ends of the molecule.
000 manufactured by Nippon Soda Co., Ltd.) 130 parts and trimellitic anhydride 3
Add 8.5 parts and 0.1 part of hydroquinone, an anti-gelling agent, gradually heat the contents to 175°C while passing nitrogen gas, and react at 175°C for 30 minutes while stirring to obtain acid-terminated polybutadiene. , cooled to 140'C, added 30 parts of xylene dropwise, then added 60 parts of Epikote 828 (epoxy equivalent: 184-194, manufactured by Ciel Chemical Co., Ltd.) and reacted at 140°C to 150°C for 30 to 60 minutes. Cool to 100°C, then add dioxane dropwise,
A solution with a solids content of about 70% was prepared.

(The acid value of the obtained polybutadiene-modified epoxy resin is 6
3) Next, Rariul sulfate ester soda 1.0y
、． Pour 500 parts of 0.3% ammonia water into four flasks, heat and stir at 70°C, then add 150 parts of the above 70% solution, reflux for 10 to 30 minutes, and heat for 4 hours at 70°C while passing Tituso gas. A stable aqueous dispersion is obtained by distilling off the ammonia and solvent.

When the aqueous dispersion obtained as above was placed in a 200CC beaker, two copper plates were placed facing each other, and a DC voltage of about 20V was applied between them, the particle layer deposited on the anode was hard and had no fluidity. 180℃ for 30 minutes at 120-150℃
The film baked at ℃ for 2 hours was uniform and had good mechanical strength.

Example 2 Acid-terminated polybutadiene 138 obtained in Example 1
30 parts of dioxane were added dropwise to the flask, and then Chitsonox 289 (epoxy equivalent: 205~
222, manufactured by Chitsuso Co., Ltd. Fine Chemicals) was added and reacted at 100 to 110°C for 60 minutes, and then heated to 70°C.
Cool to about 65% solids by adding acetone dropwise.
(The acid value of the obtained polybutadiene-modified epoxy resin was 42) Next, 600 parts of 1.570.4% ammonia water with sodium laurylbenzenesulfonate were charged into four flasks and heated to 75°C with stirring. Then, 170 parts of the above 65% solution was added, and after refluxing for 10 to 30 minutes, the ammonia and solvent were distilled off for 5 hours while passing nitrogen gas at 70 to 75°C, resulting in a stable aqueous dispersion. is obtained.

The aqueous dispersion obtained above was electrodeposited in the same manner as in Example 1, and the electrodeposited film was heated at 110 to 120°C for 30 minutes, and then for 17
The film baked at 0°C for 3 hours was uniform and had good mechanical strength.

Example 3 138 parts of the acid-terminated polybutadiene obtained in Example 1 were placed in four Lough flasks, 30 parts of xylene was added dropwise, and then 90 parts of Epikote 154 (epoxy equivalent: 176-181, manufactured by Ciel Chemical Co., Ltd.) was added to give 130 parts of the acid-terminated polybutadiene obtained in Example 1. 30-60 at ~140℃
After reacting for a minute, it was cooled to 80°C, and then methyl ethyl ketone was added dropwise to make a solution with a solid content of about 70% (the acid value of the obtained polybutadiene-modified epoxy resin was 25). Sulfonate 1.5 parts, 0
．． 600 parts of a 4% trimethylamine aqueous solution was placed in a four-necked flask, heated to 70'C, stirred, and then added to the above 70% solution.
Add 150 parts of the solution, reflux for 10 to 30 minutes, and then distill off the trimethylamine and solvent at 70°C for 5 hours while blowing air to obtain a stable aqueous dispersion.

The aqueous dispersion obtained above was electrodeposited in the same manner as in Example 1, and the electrodeposited film was heated at 120 to 130'C for 30 minutes, and then for 20 minutes.
The film baked at 0° C. for 1 hour was uniform and had good mechanical strength.

Example 4 130 parts of 1,2-added polyptadiene having a number average molecular weight of 1300 and having hydroxyl groups at both ends used in Example 1 and 19.6 parts of maleic anhydride were placed in a reaction vessel equipped with a thermometer, a stirrer, and a gas introduction tube. , and gradually heated the contents to 100°C while passing nitrogen gas, and reacted at 100°C for 60 minutes with thorough stirring to obtain acid-terminated polybutadiene. Next, 30 parts of xylene was added dropwise, and then Epicote 1
After adding 100 parts of 001 (epoxy equivalent: 450-500, manufactured by Ciel Chemical Co., Ltd.) and reacting at 130-140°C for 30-60 minutes, it was cooled to 100°C, and then dioxane was added dropwise to reduce the solid content to about 70%. (The acid value of the obtained polybutadiene-modified epoxy resin was 20.) Next, 1.0 part of sodium lauryl sulfate and 80 parts of 0.4% aqueous ammonia were added.
Pour 0 parts into three flasks, heat and stir at 80°C, then add 150 parts of the above 70% solution, and add 10 to 30 parts.
After refluxing for a minute, a stable aqueous dispersion was obtained by distilling off the ammonia and solvent at 75° C. for 6 hours while passing nitrogen gas through the solution.

The aqueous dispersion obtained as described above was electrodeposited in the same manner as in Examples 1 and 5, and the electrodeposited film was heated at 100°C for 30 minutes and further heated at 180°C.
The film baked for 2.5 hours was uniform and had good mechanical strength.

Example 5 A 1C reaction vessel equipped with a thermometer, a stirrer, and a gas introduction tube was prepared with a number average molecular weight of 2 having hydroxyl groups at both ends of the molecule.
000 1/2 addition polybutadiene (NiSSO-PB
．． 100 parts of G-2000 (manufactured by Nippon Soda), 19.7 parts of trimellitic anhydride, and 0.5 parts of tertiary-butylhydroxytoluene as an anti-gelling agent were added, and the contents were gradually heated to 175°C while passing nitrogen gas. and 175℃～1
Acid-terminated polybutadiene was obtained by reacting at 80°C for 30 minutes, cooled to 140°C, 30 parts of xylene was added dropwise, and *(
Next, add 82,850 parts of Epicoat and raise the temperature to 140-150°C.
After reacting for 30 to 60 minutes, the mixture was cooled to 70°C, and then methyl ethyl ketone was added dropwise to form a solution with a solid content of about 60%.

(The acid value of the obtained polybutadiene-modified epoxy resin is 3
It was 0. ) Next, 1.5 parts of sodium laurylbenzenesulfonate and 600 parts of 0.4% ammonia water were charged into four flasks, heated to 70°C and stirred, and then the above 60%
180 parts of the solution was added, and after refluxing for 10 to 30 minutes, excess ammonia and solvent were distilled off at 75° C. while passing nitrogen gas for 6 hours to obtain a stable aqueous dispersion.
The aqueous dispersion obtained as described above was electrodeposited in the same manner as in Example 1, and the electrodeposited film was heated at 100°C for 30 minutes and further at 180°C for 2 hours.
The time-baked film was uniform and had good mechanical strength.

The film characteristics of the examples described above are shown in the table.

Claims (1)

[Scope of Claims] 1. Obtained by reacting a reaction product of hydroxy polybutadiene having a hydroxyl group at the end of its molecular chain and an acid anhydride of a polybasic acid with an epoxy resin having two or more epoxy rings in the molecule. An electrodeposition paint characterized by containing a polybutadiene-modified epoxy resin having an acid value of 20 to 100 as a main ingredient. 2. The electrodeposition coating material according to claim 1, wherein the reaction product has an acid value of 40 to 300. 3. The electrodeposition paint according to claim 1 or 2, wherein the epoxy resin is of a bisphenol type. 4. The electrodeposition paint according to claim 1 or 2, wherein the epoxy resin is a novolac type. 5. The electrodeposition paint according to claim 1 or 2, wherein the epoxy resin is an alicyclic resin.