JPS6291568A - Low-temperature baking water paint resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent resistance to impact, corrosion and solvents and suitable for use in cationic electro deposition coating, by blending a resin having both Oh and cationic groups with a specified polyurethane resin and a polyepoxide. CONSTITUTION:A resin (A) having OH group in an amount of a hydroxyl number of about 10-400 and cationic groups in an amount of 5-160 in terms of KOH (mg/g of solid) is blended with a polyurethane resin (B) having no free isocyanate group and having an MW of 400-3,000 which is a reaction product of a phenol compd. composed of a polyphenol having at least two phenol groups and optionally, a monophenol with a polyisocyanate having at least two isocyanate groups [e.g., a reaction product of a bis(4-hydroxyphenyl)alkane with a polyisocyanate having at least two isocyanate groups] and a polyepoxide (C) having at least two epoxy groups [e.g. an epoxidized butadiene (Co)polymer].

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition for low-temperature baking type water-based paint,
More specifically, it is a low-temperature coating suitable for cationic electrodeposition coating, which is suitable for integrated coating of objects made of thermoplastic materials such as plastics and rubber and metal, which require low-temperature baking, and coating of castings. The present invention relates to a resin composition for baking type water-based paint.

Conventionally used cationic electrodeposition paints are typically composed of a water-soluble epoxy resin such as bisphenol A-epichlorohydrin epoxy resin and an aromatic polyisocyanate compound blocked with alcohol. The coating film obtained by electrodepositing this material and curing it at, for example, 170°C has excellent corrosion resistance, but because the curing temperature is high, thermoplastic materials such as plastics and rubber (fat and zinc phosphate treatment) It is unsuitable for applications that require curing in the temperature range of room temperature to 130° C., such as integral coating of objects made of metal such as plates, and coating of castings.

Therefore, in order to obtain electrodeposition coatings that can be cured at low temperatures, large amounts of catalysts that dissociate isocyanate compounds blocked with alcohols at low temperatures have been used.
However, the problem still requires high temperatures and has not yet been solved.

In order to enable low-temperature curing at 130'C or less, it is possible to use phenols, oximes, tIS3 heroxyamines, caprolactams, active methylene compounds, etc. as blocking agents. When used in paints, there are at least one of the following problems: ■ Toxicity of the blocking agent, ■ Insufficient compatibility with the base resin, ■ Generation of smoke or tar during baking, and ■ Instability of the blocked product. In particular, when baking at a low temperature of 130°C or lower, these blocking agents remain in the coating even after baking, reducing corrosion resistance and causing defects such as bleeding and yellowing. Moreover, the residual blocking agent itself is highly harmful (toxicity, odor), making it difficult to put it into practical use. Therefore, as a method for solving these problems, the present inventors first prepared (A) a resin having a hydroxyl group and a cationic group, and (B) a polyphenol containing at least two phenol groups and at least two isocyanate groups. We have proposed a resin composition for low-temperature baking water-based paints that contains as its main component a polyurethane resin whose terminal end is a phenol group, which is a reaction product with the polyisocyanate it contains (see specification of Japanese Patent Application No. 197781/1981). .

This product has excellent suitability for curing at low temperatures of 130°C or lower, and almost all of the solids in the resin composition, excluding water and volatile solvents, participate in the formation of a cured coating, resulting in a coating with good coating performance. This is a resin composition that provides. However, there is still free poly7 in the heat-cured coating film obtained in this way.
Contains alcohol. That is, among the polyisocyanate and polyphenol components that form the polyurethane resin that is the curing resin, when the polyisocyanate is bonded to the base resin by a curing reaction, the polyphenol that is left behind is present alone in the coating film. Although this polyphenol does not have an adverse effect on the water resistance, slip spray resistance, etc. of the coating film, there is a problem in that it has a somewhat adverse effect on the solvent resistance, other physical properties, etc. Therefore, the present inventors have developed a method that does not have these problems, that is, has excellent low-temperature curing suitability at 130'C or less, and has excellent not only water resistance and corrosion resistance, but also solvent resistance and other physical properties, especially cationic electrodeposition. As a result of extensive research in order to obtain a resin composition for low-temperature baking water-based paints suitable for painting, we found that the previously proposed composition contains at least two 7-er groups produced by thermal decomposition of polyurethane resin. By using a polyepoxide containing at least two epoxy groups as the third component, which is reactive with polyphenols and monophenols added as necessary, it cures at a low temperature of 130°C or less, and has excellent solvent resistance and other properties. A coating resin composition that has excellent physical properties, in which almost all of the solids in the resin composition except for water and volatile solvents participates in the formation of a cured coating film, and provides a coating film with good anticorrosive coating performance. The present inventors discovered that the present invention can be obtained and completed the present invention.

Thus, according to the present invention, 1. (A) a resin having a hydroxyl group and a cationic group; (B) a poly7 containing at least two 7-el groups;
A polyurethane resin having no free isocyanate groups, which is a reaction product of a phenol compound obtained by adding a monophenol to this and a polyisocyanate containing at least two isocyanate groups,
and (C) a resin composition for a low-temperature baking type water-based paint, which is characterized by containing as a main component a polyepoxide containing at least two epoxy groups.

In the present invention, the resin (A) having a hydroxyl group and a sicationic group (hereinafter sometimes referred to as "base resin (A)") is a resin that contains a hydroxyl group that can react with an isocyanate group and is stable. Any resin having a sufficient number of cationic groups to form an aqueous dispersion is used. Examples of the base resin (A) include the following.

(1) A reaction product obtained by reacting a polyepoxy resin with a cationizing agent; (ii) A polycondensate of a polycarboxylic acid and a polyamine (see U.S. Pat. No. 2,450,940) (iii) Polyadducts of polyisocyanates and polyols with mono- or polyamines are protonated with acids; (iv) Copolymers of acrylic or vinyl monomers containing hydroxyl groups and amine 7 groups. Protonated with acid (Japanese Patent Publication No. 45-12395, Japanese Patent Publication No. 45-12
(see US Pat. No. 396); (v) an adduct of polycarboxylic acid resin and fullkyleneimine protonated with acid (US Pat. No. 3,40);
3,088); etc.

For specific examples and manufacturing methods of these cationic I(III?), see, for example, Japanese Patent Publications No. 12395-1982, No. 12396-1980, No. 23087-1987, and U.S. Patent No. 2,450,940. Specification, U.S. Patent fjIJ3,403,088, U.S. Patent No. 3
, No. 891.529, U.S. Patent No. 3,933.
, No. 663.

Particularly desirable as the base resin (A) in the present invention are agents for cationizing the epoxy groups of a polyepoxide compound obtained from a poly(7-functional) compound and epichlorohydrin because of their excellent anticorrosion properties. It is a reaction product obtained by reacting epoxy groups, which may have residual epoxy groups.

The polyepoxide compound is an epoxy base, generally at least 200, preferably from 400 to 4,000,
More preferably, those having a number average molecular weight within the range of 800 to 2,000 are suitable. As such an Evoquinde compound, those known per se can be used. For example, poly 7 ether/- which can be produced by reacting poly 7 ether/- with epichlorohydrin in the presence of an alkali. The polyglycidyl ethers of Examples of the poly7enyl that can be used here include bis(4-hydroxy7enyl)-2,2-propane, 4,4'-dihydroxybenzophenone, and bis(4-hydroxy7enyl)-2,2-propane, 4,4'-dihydroxybenzophenone,
4-bitroxyphenyl)-1゜1-ethane, bis-(
4-hydroxyphenyl)-1゜1-ynebutane, bis(4-hydroxy-tert-butyl-phenyl)-2
, 2-propane, bis(2-hydroxynaphthyl)methane, 1f5-dihydroxynaphthalene, bis(2,4-
(4-hydroxyphenyl)methane, tetra(4-hydroxyphenyl)-1,1,2゜2-ethane, 4.4'-nohydroxynophenyl ether, 4.4'-nohydroxynophenyl ether, 4.4' -nohydroxydiphenylsulfone, phenol/borac, cresol/borac, and the like.

Among the above-mentioned polyepoxide compounds, those particularly suitable for the production of base resin A have a number average molecular weight of at least about 3.
80, preferably about 800 to 2,000, and an epoxy equivalent weight of 190 to 2,000, preferably 400 to 1.000.
It is represented by the following general formula within the range of . The polyepoxide compound may be partially reacted with polyol, polyether polyol, polyester polyol, polyamide amine, polycarboxylic acid, polyisocyanate, etc., and may also be graft-polymerized with ε-caprolactone, acrylic monomer, etc.

On the other hand, examples of the cationizing agent reacted with the polyepoxide compound include aliphatic, alicyclic, or aromatic-aliphatic primary or secondary amines, tertiary amine salts, secondary sulfide salts, and tertiary phosphine salts. Examples include salt. These react with epoxy groups to form cationic groups.

Furthermore, a tertiary amino monoisocyanate obtained by the reaction of a tertiary amino alcohol and a diisocyanate can be reacted with a hydroxyl group of an epoxy resin to form a cationic group.

Examples of the amide/compound in the cationizing agent include:
For example, the following can be exemplified.

(1) Methylamine, ethylamine, n- or 1s
Primary amines (2) such as o-propylamine, mo/etha/-7leamine, n- or 1so-propylamine (2)
Secondary amines such as noethyloleamine, ethanolamine, n- or 1so-propylamine, N-methylnitinolamine, N-ethylethanolamine (3) Ethylenenoamine, noethylenetriamine, hydroquinethylamino Polyamines such as ethylamine, dithylaminoethylamine, methylaminopropylamine, trimethylaminoethylamine, and trimethylaminopropylamine, and among these, alkanolamines having a hydroxyl group are preferred. The primary amine 7 group may be blocked by reacting with a ketone in advance, and then the remaining active hydrogen may be reacted with an epoxy group.

Furthermore, in addition to the above-mentioned amine compounds, basic compounds such as ammonia, hydroxylamine, hydrazine, and hydroxyethylhydrazine can also be used. The basic group formed using these compounds is protonated with an acid, particularly preferably a water-soluble organic carboxylic acid such as formic acid, acetic acid, or lactic acid, to form a cationic group.

Furthermore, triethylamine, triethanolamine, N
, N-nomethylethynohelamine, N-methyljetanolamine, N,N-noethylethylamine, N-
Tertiary amines such as methyljetanolamine can be used, and these can be preprotonated with an acid and converted into a quaternary salt with an epoxy group.

In addition to amino compounds, salts of sulfides such as quetyl sulfide, nophenyl sulfide, tetramethylene sulfide, and thiogetanol with boric acid, carbonic acid, and organic monokanebonic acids can be reacted with epoxy groups to produce tA tertiary Good as a sulfonium salt.

Furthermore, phosphines such as triethylphosphine, phenyldimethylphosphine, diphenylmethylphosphine, and triphenylphosphine may be reacted with the above-mentioned acids to form a quaternary phosphonium salt.

The hydroxyl group content of the base resin (A) used in the present invention is generally preferably in the range of about 10 to 400, particularly 20 to 200 in terms of hydroxyl value, from the viewpoint of reactivity with polyisocyanate.

In addition, the content of the cationic group is desirably small enough to stably disperse the base (M fat (A)) in water;
Generally, a range of 5 to 160, particularly 10 to 80 in terms of H (ug/g solid content) is preferred. However, even if the cationic group content is 5 or less, it is possible to use aqueous dispersion using a 1llllL surfactant, etc.
It is desirable to adjust the cationic group so that r+H of the aqueous dispersion composition is 4 to 9, preferably 6 to 7.

Next, the polyurethane resin (B) having no free isocyanate groups, which is used in combination with the base resin (A), will be explained.

Polyurethane resin (B) without free isocyanate groups used in the present invention (hereinafter referred to as [curing resin +
11? (B)J)'s! ! The polyisocyanates used in the latter are polyisocyanates containing at least two isocyanate groups. Preferably, the polyisocyanate has a total of 2 to 3 isocyanate groups and a molecular weight in the range of 150 to 600. Typical examples of such polyisocyanates are 4,4
Aromatic isocyanates such as '-diphenylmethane diisocyanate; aliphatic noisocyanates such as hexamethylene diisocyanate and gimaric acid noisocyanate); cycloalkylenes such as 1,4-nocyclohexylmethane noisocyanate and isophorone diisocyanate. Ring-containing diisocyanates; aromatic-aliphatic diisocyanates such as l-1 or p-xylylene diisocyanate; suitable polyisocyanates include alicyclic polyisocyanates that have excellent weather resistance and are used in 2-foot finishing undercoat paints; Low-volatility 4,4'-dicyclohexylmethane diisocyanate suitable for this purpose is mentioned.

A curing resin (B ) can be generated.

The polyphenol preferably has a total of 2 to 3 72/-l groups and a molecular weight in the range of 100 to 600. A typical example of polyphenol is bis(4-hydroxy7enyl)-212-7'
Lopane, 4,4'-dihydroxybenzophenone, bis(4-hydroxyphenyl)-1°1-ethane, bis(
4-hydroxyphenyl)-1,1 isobutane, bis(
4-hydroxyphenyl)-2゜2-isobutane, bis(4-hydroxy-tert-)+luphenyl)-2,
2-propane, bis(2-hydroxynaphthyl)methane, 1,5-nohydroxynaphthyl 7talene, novolac phenol resin (di- to trinuclear), etc., and bis(4-hydroxy, which is easily available industrially). Phenyl)-2,2-propane and novolak phenolic resins are preferred.
゛Moreover, the monophenol preferably has a molecular weight in the range of 90 to 600. Representative examples of such monophenols include /nylphenol, a- or β
-su7toll, p-tert-octylphenol,
Examples include 〇- or p-phenylphenol, and p-phenylphenol, which is industrially easily available and easy to handle, is preferred.

The reaction for producing a polyurethane resin (B) having no free isocyanate groups from such a polyisocyanate, polyphenol, and optionally added mono7 esters can be carried out in the absence of a solvent or in the presence of, for example, toluene,
Generally in the presence of an inert organic solvent such as xylene, dioxane, methyl ethyl ketone, ethyl acetate, etc.
It can be done at 0℃. The reaction may be carried out in the presence of a urethanization catalyst such as dibutyltin noacetate, butyltin nolaurate, etc., if necessary. The amount of polyphenol and optionally added monophenol relative to the polyisocyanate is a ratio of more than 1 equivalent and less than 2 equivalents, more preferably 1.2 to 1.5 times the equivalent of the isocyanate group of the polyisocyanate. The amount of polyphenols corresponding to the amount of 7 enol groups and the amount of monophenol added as necessary. Both ends of the polyurethane resin may be phenol groups, and if necessary, monophenols may be used to stop the increase in molecular weight. The thus obtained curing resin (B) (i'l
Molecular weight C, usually 400-3,000. Preferably 1.00
The range is 0 to 2,000.

The amount of curing resin (B) used when mixing the curing resin (B) with base resin (A) depends on the type of base resin (A) used, and whether the resulting coating film is self-curing or heat-curing. The amount can be varied from the minimum amount required for curing to the maximum amount that does not impair the stability of the aqueous dispersion coating, but in general, the number of isocyanate groups reacted with the phenol groups in the curing resin (B) ( It is preferable that the number of equivalents) is approximately equal to the total amount (number of equivalents) of the active hydrogen-containing functions m and f in the base resin (A).

Next, the polyepoxide (C) containing at least two epoxy groups and used in combination with the base resin (A) and the curing resin (B) will be described.

The polyepoxide (C) containing at least two epoxy groups (hereinafter also referred to as "curing resin (C)") used in the present invention includes polyphenol and mono7 ether added as necessary. Any resin containing an effective number of epoxy groups to react may be used, but particularly preferred are stable polyepoxides that coexist in water with the base resin (A) having cationic groups over long periods of time.

Representative examples of such polyepoxides include the following.

1) Polyepoxides obtained by epoxidizing natural oils such as linseed oil, tung oil, soybean oil, and dehydrated castor oil, or stand oils obtained by heat-treating these natural oils (e.g., JP-A-53-16048) ii) Polymers of conjugated diolefins such as butanoene, isoprene and piperylene and/or copolymers of these conjugated diolefins; one or more of the above conjugated diolefins and ethylenically unsaturated copolymers with vinyl monomers having a group such as imbutylene, styrene, vinyltoluene, etc. (see, for example, Japanese Patent Publication No. 60-25466); iii) Ethylenically unsaturated polymerization epoxy group-containing monomers, such as butadiene monoepoxide, 4-vinylcyclohexene monoepoxide, etc. Or a copolymer of two or more of the above conjugated diolefins and/or a vinyl monomer having an ethylenically unsaturated group (see, for example, JP-A-54-15935 and JP-A-57-139147).

Particularly desirable polyepoxides in the present invention are epoxidized polybutadiene polymers and/or copolymers that are compatible with bisphenol A epoxide resins and significantly improve physical properties and solvent resistance.

The above-mentioned polyepoxide is a compound having 2 or more, preferably 5 to 20, epoxy groups in one molecule, which are obtained by epoxidizing a carbon-carbon double bond, and generally 200 or more, preferably 400 to 50. ooo, more preferably 1, OOO~4.

Those having a number average molecular weight in the range of 0.000 are suitable. As such polyepoxides, those known per se can be used. For example, epoxide resins obtained by epoxidizing a compound whose main chain is a polymer of conjugated diolefins such as butadiene, isoprene, and piperylene are used. Included. As the compound forming the main chain portion of the epoxide resin, those having an iodine value of 100 to 5,001, preferably 200 to 450, and a number average molecular weight of 200 or more, preferably i, o o o to 4,000 are advantageously used. The compound that becomes this main chain part has the general formula (where, R2 is a hydrogen atom or a methyl group; X is a hydrogen atom or a bond, and when X is a bond, the carbon atom to which R1 is attached and the The attached carbon atoms can together form part of the main chain) An epoxy group is introduced. For the introduction of epoxy groups, for example, a conventionally known method of reacting peracetic acid at a temperature of 0 to 100°C can be used (for example, Japanese Patent Publication No. 37
(Refer to Japanese Patent Publication No. 15107 and Japanese Patent Publication No. 38-8289). The amount of epoxy groups represented by the above general formula is from 50 to 5,000, preferably from 100 to 300, in terms of weight. The polyepoxide may be partially reacted with a substance that reacts with an epoxy group, such as amine, phenol, carboxylic acid, or alcohol, to increase its reactivity.

The amount of the curing resin (C) to be used when mixing the curing resin (C) with the base resin (A) and the curing Q (fat (B)) should be determined so that the resulting coating film has the best physical properties and solvent resistance. , select the optimum amount necessary to obtain performance such as water resistance and spray resistance.
However, in general, the number of epoxy groups (equivalent number) in the curing resin (C) is a phenol that has already reacted with the unreacted phenol groups and zoisocyanate groups contained in the curing resin (B). It is preferable to adjust the amount to about % to 2 times the total number of groups (number of equivalents), preferably % to 1 times the equivalent. In this case, the polyphenols dissociated from the polyurethane resin during curing and the monophenols added as necessary are combined with the curing resin (C) in the coating film and do not volatilize and scatter, so the use of monophenols is effective II). becomes.

Thus, the composition consisting of the base resin (A), the curing resin (B), and the curing resin (34 resin) can be used as a resin component for water-based paints that can be baked at low temperatures of 130°C or less. To prepare a resin composition for water-based paint,
Base resin (A), curing resin (B), and curing resin (C
), then add water 1. Stabilize the dispersion and then add carbon black, titanium white, ben
This is done by kneading colored pigments such as clay; extender pigments such as clay and talc; anticorrosion pigments such as strontium chromate and lead chromate; or other additives.

Other additives that may be included include, for example, a small amount of nonionic surfactant as a dispersant or anti-repellent agent for the coated surface;
Examples include curing preservatives (for example, salts of metals such as lead, bismuth, tin, zinc, iron, and aluminum, and/or imigzoline compounds, imidazoles), and the like.

The resin composition for aqueous paints thus prepared can be used, for example, for cationic electrodeposition coating. The coating film obtained by electrodeposition on a suitable substrate is, for example, 130
C. or less, preferably 80 DEG C. to 130 DEG C., but if desired, curing at room temperature is also possible. The reason for this is that the acid is removed from the resin composition that has not been neutralized by the acid by electrodeposition, and the pH of the deposited film becomes high, thereby promoting the curing reaction. This also applies when other coating methods useful for water-based paints for room temperature drying or low temperature baking are used.

The low-temperature curing aqueous coating composition of the present invention is advantageously used for the integral coating of objects made of thermoplastic substances such as platylas and rubber and metals, particularly for the cationic electrodeposition coating of castings. be able to.

Next, the present invention will be further explained by examples. All parts in the examples are "parts by weight", and "%" is 1% by weight.

In addition, the "throwing property", "silt spray resistance", "impact resistance", "bending resistance", and 'solvent resistance' of the coating compositions obtained in the following examples were measured by the following methods. It is something.

(1) Throwing property test method (pipe method) JP-A-55-9
The method is based on the method described in Publication No. 0566. .

(2) Tested according to JIS 22871, and passed if creep from the cut (linear cut) part is within 2.0am on one side and 7 creases of the coating film other than the cut part is 8F (ASTM) or less. .

(3) Impact resistance (Debon method) After placing the test plate in a constant temperature and humidity room with a temperature of 20 ± 1°C and a humidity of 75 ± 2% for 24 hours, place it in a DuPont impact tester with a cradle of the specified size. Attach the impact center, place the test plate between them with the painted surface facing upward, and then drop a weight of the specified weight onto the impact center from the specified height to prevent cracking of the paint film due to impact.
Pass the test if there is no problem.

(4) Bending resistance test The plate was placed in a constant temperature and humidity chamber at a temperature of 20±1°C and 75±2% for 24 hours, and then bent at a right angle for 1 to 2 seconds. A cured coating film is applied to both the front and back sides of the test plate. If there is no abnormality on both sides of the folded part, the product is passed, and if at least one of the bent parts has an abnormality such as cracks or scratches, the product is judged to be rejected.

(5) Solvent Resistance If the product contains methyl isobutyl ketone and is not scratched even after wiping it back and forth 15 times with a diluted wipe, it is considered to be a pass, and if it cannot withstand it, it is judged to be a fail.

Example 1 1,900 parts of a bis-7 ether/A type epoxy resin (trade name: Pico) having an epoxy equivalent of 950 (trade name: GI), Shell Chemical Co., Ltd., was dissolved in 1,012 parts of butyl cellosolve, and 124 parts of noethylamine was dissolved in 80 to 80 parts of butyl cellosolve. After dropping at 100°C, the mixture was maintained at 120°C for 2 hours to obtain an Evoquin resin-amine adduct having an amine value of 47.

Next is a guimaric acid type polyamide resin with an amine value of 100 (trade name: Persamide 460, manufactured by Henkel Hakusui Co., Ltd.)!
! 1,000 g of the solution was dissolved in 429 parts of methyl imbutyl ketone, heated to 130 to 150°C under reflux, the water produced was distilled off, and the 7 terminal amino groups were converted to ketimine. this thing 1
Hold at 50°C for about 3 hours, and after water distillation stops, hold at 60°C.
Cool to 0°C.

Next, this product was added to the epoxy resin-amine adduct, heated to 100°C, held for 1 hour, and then cooled to room temperature to obtain an epoxy resin-amine-polyamide adduct resin (A) with a solid content of 68% and an amine value of 65. get. 1.5 parts of acetic acid is added to 100 parts of this resin to neutralize it. Next, 7.3 parts of 4-4' cyclohexyl 7-tannoisocyanate and bis(4
-Hydroxy7enyl)-2,2-propane (7.9 parts) was dissolved in 7.6 parts of methylimptyl ketone, 1 drop of noptyltinnolaurate was added, and the mixture was reacted at 120°C for 12 hours. After cooling to room temperature, a curing resin (B) is synthesized.

The epoxy equivalent of 200 and the viscosity of 700 points at 25° C. are added to the neutralized product of the epoxy resin-7min-boryamide addition resin (A) obtained in this way. Add 20 parts of polybutanoene (trade name: E-1000, manufactured by Nippon Petrochemicals Co., Ltd.), and while stirring thoroughly, add 272 parts of deionized water to form an electrodeposition bath with a solid content of 20 parts and a VpH of 6.2. make.

Using this electrodeposition bath, a zinc phosphate treated plate was used as a cathode to form a mold at 30° C. and 250 μm for 3 minutes, and then baked at 120° C. for 30 minutes to obtain a coating film with a thickness of 24 μm and a pencil hardness of 3H. The performance of this coating film is as follows.

(1) Impact resistance <3A inch, 1 kg, 50cm
) Passed (2) Tsuruto spray resistance (240 hours) Passed (3) Throwing property 2Oc theory (
4) Flexibility Resistance Pass (5) Solvent Resistance Pass Example 2 101.5 parts of the acetic acid neutralized product of the epoxy resin-amine-polyamide addition resin (A> used in Example 1) and 22 parts of the curing resin (B) .8 parts, epoxy equivalent: 200, viscosity: 4
At 5°C, 15 parts of epoxidized polybutanoene (trade name R-45EPI, manufactured by Idemitsu Petrochemical Co., Ltd.) with 360 voids was added, and while stirring thoroughly, 277 parts of deionized water was added to reduce the solid content to 20 parts ( /Create an electrodeposition bath with a pH of 6.3.Use this 'Ki deposition bath to form a coating film at 30°C and 200V for 3 minutes using a zinc phosphate treated plate as a cathode.
Bake at 20℃ for 30 minutes to achieve a thickness of 20μ and a pencil hardness of 3.
A coating film of H is obtained. The performance of this a-film is as follows.

(1) Impact resistance (% inch, 1 kg, 50cm) passed (2) Tsuruto spray resistance (240 hours) passed (3)
Throwing property 19c (4) Flexing resistance Pass (5) Solvent resistance
Passing Comparative Example Neutralized product ioi, s part and curing resin (B) of epoxy resin-amine-polyamide addition resin (A) used in Example 1
) Add an additional 292 parts of deionized water to 22.8 parts of the solution with thorough stirring to create an electrodeposition bath with a solids content of approximately 20% and a pH of 6.5. Using the zinc phosphate treated plate as a cathode in the electrodeposition bath, the resulting coating film was molded at 30°C and 200cm for 3 minutes, and baked at 120°C for 30 minutes to form a 22μ thick and 3H pencil hardwood coating. Obtain a membrane. The properties ff8 of this coating film are as follows.

(1) Impact resistance (inch, 1 kg, 50ca+
)failure

Claims (1)

[Claims] 1. (A) a resin having a hydroxyl group and a cationic group, (B) a polyphenol containing at least two phenol groups, a phenol compound obtained by adding monophenol to this as necessary, and an isocyanate group. (C) a polyurethane resin having no free isocyanate groups which is a reaction product with a polyisocyanate containing at least two epoxy groups; Resin composition for baking type water-based paint. 2. The polyurethane resin (B) contains at least two bis(4-hydroxyphenyl)alkanes and isocyanate groups.
The composition according to claim 1, which is a reaction product having no free isocyanate groups with a polyisocyanate containing polyisocyanate. 3. The composition according to claim 1, wherein the polyepoxide (C) is an epoxidized butadiene polymer and/or an epoxidized butadiene copolymer.