JP3100652B2 - Baking type water-soluble coating resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a baking type water-soluble coating.
The present invention relates to a method for producing a resin . Specifically, the present invention relates to adhesion,
Excellent water resistance, corrosion resistance, solvent resistance and storage stability
The present invention relates to a method for producing a baking type water-soluble coating resin .

[0002]

2. Description of the Related Art It is widely known that a coating composition using an epoxy resin has excellent adhesion and corrosion resistance. However, a coating composition containing an epoxy resin of a two-liquid mixture type has a problem in workability. However, emulsion paints and water-soluble paints have the drawback that the original performance of epoxy resins cannot be obtained. One-pack curable aqueous resins comprising a water-soluble epoxy resin-amine adduct and a blocked isocyanate compound are also known, but those using isocyanate compounds blocked with alcohols and lactams have good stability. However, the disadvantage is that the baking temperature is high. In addition, those using isocyanate compounds blocked with oximes and phenols can be cured at a low temperature of 130 ° C or lower, but a large amount of dissociation catalyst is mixed to lower the dissociation temperature, Extremely high storage stability is extremely poor, water resistance of the coating film,
There are drawbacks such as poor corrosion resistance and poor solvent resistance.

[0003] Such a coating composition is disclosed in
No. 4978 discloses a polyglycidyl ether of polyphenol and an acid salt adduct of 2-ethylhexanol half-blocked toluene diisocyanate / dimethylethanolamine.

JP-B-59-5563 discloses a product obtained by neutralizing an epoxy resin-amine adduct and a phenol half-blocked isocyanate reactant with an acidic substance.

Japanese Patent Application Laid-Open No. 62-129363 discloses a mixture of a resin having an epoxy group, a hydroxyl group and an amino group and a polyphenol fully blocked isocyanate resin.

[0006]

However, the composition disclosed in JP-B-54-4978 is not preferred in that the curing temperature is as high as 150 ° C. or higher.

The composition disclosed in Japanese Patent Publication No. 59-5631 is as follows:
Although low-temperature curing at 00 ° C. is possible, it has disadvantages such as poor corrosion resistance of the cured coating film and poor long-term stability at room temperature.

Further, the composition disclosed in JP-A-62-129363 can be cured at a low temperature of 100 ° C., but also has the disadvantage that the cured coating film has poor corrosion resistance and poor long-term stability at room temperature. is there.

As described above, low-temperature baking at a temperature of 100 ° C. or less is possible, and the adhesiveness, water resistance, corrosion resistance, and solvent resistance of the original epoxy resin are excellent. Baking type water-soluble coating resins have not yet been put to practical use.

An object of the present invention is to solve the above-mentioned problems.
An object of the present invention is to provide a method for producing a baking type water-soluble coating resin .

[0011]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is,
The method for producing the baking type water-soluble coating resin of the present invention
The xy group-containing resin (I) contains at least one active water
Phosphate (II) containing silicon
Active hydrogen equivalent of 0.1 to 1 equivalent of epoxy group of (I)
Phosphorus-containing epoxy obtained by reacting to 0.5
An amine compound (III) is added to a resin (A),
Active hydrogen equivalent per 1 equivalent of epoxy group of resin (A)
Phosphorus containing obtained by reacting to 0.8-1.1
Epoxy resin-amine adduct (B) and partial block
After reacting the polyisocyanate (C), pH 4 with acid
-6 .

The phosphorus-containing epoxy resin-amine adduct (B) of the present invention is a phosphorus-containing epoxy resin obtained by reacting an epoxy group-containing resin (I) with a phosphate (II) having at least one active hydrogen. It is obtained by reacting an amine compound (III) with the resin (A).

As the epoxy group-containing resin (I) used in the present invention, those containing two or more epoxy groups in one molecule and having a molecular weight of 200 to 2,000, preferably 350 to 1,000 are suitable. The following are examples of such an epoxy group-containing resin (I).

An epoxy resin obtained from epichlorohydrin or β-methylepichlorohydrin and bisphenol A, bisphenol F or bisphenolsulfone, polyglycidyl ether of novolak resin, polyglycidyl ether of ethylene oxide or propylene oxide adduct of bisphenol A,
Polypropylene glycol, neopentyl glycol,
Polyglycidyl ethers of polyhydric alcohols such as 1,6-hexanediol, glycerin, trimethylolpropane, etc .; polyglycidyl esters of polycarboxylic acids such as adipic acid, phthalic acid, hexahydrophthalic acid and dimer acid; polyglycidyl Amines and the like. Further, an epoxy resin obtained by modifying the above epoxy resin with a polyphenol such as bisphenol A or bisphenol F, or a polycarboxylic acid such as adipic acid or sebacic acid can also be used.

The phosphate (II) having at least one active hydrogen used in the present invention includes phosphorus
Examples include acids , phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid monosalts, and phosphoric acid disalts . Phosphoric acid
Monoesters include monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, and the like.
Phosphoric diesters include dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, and the like. Monophosphate salts include monosodium dihydrogen phosphate, potassium monohydrogen phosphate, and monohydrogen phosphate. Examples of diphosphates such as ammonium include disodium monohydrogen phosphate, dipotassium monohydrogen phosphate, diammonium monohydrogen phosphate, calcium phosphate and the like.

Of the phosphates (II) having one or more active hydrogens, phosphate monoesters and phosphate monosalts having two active hydrogens are preferred.

The phosphorus-containing epoxy resin (A) of the present invention is obtained by reacting the above-mentioned epoxy group-containing resin (I) with a phosphate (II) having at least one active hydrogen. In the reaction, the active hydrogen equivalent of the phosphate (II) having at least one active hydrogen is 0.1 to 0.5 equivalent to 1 equivalent of the epoxy group of the epoxy group-containing resin (I).
Do with .

Next, as the amine compound (III) of the present invention, aliphatic and alicyclic primary amines, secondary amines and polyamines can be used. Examples of such primary amines include methylamine, ethylamine, n-propylamine, iso-propylamine, and monoethanolamine, and examples of secondary amines include diethylamine, diethanolamine, diisopropanolamine, and N-methylamine. Polyamines such as ethanolamine and N-ethylethanolamine include ethylenediamine, diethylenetriamine, hydroxyethylaminoethylamine,
Methylaminopropylamine and the like can be exemplified.

Of these, preferred are diethanolamine having a primary hydroxyl group, N-methylethanolamine, N-ethylethanolamine and the like.

The phosphorus-containing epoxy resin-amine adduct (B) of the present invention is obtained by reacting the amine compound (III) with the phosphorus-containing epoxy resin (A) obtained by the above reaction. The reaction was conducted using the epoxy group 1 of the phosphorus-containing epoxy resin (A).
The active hydrogen equivalent of the amine compound (III) is
0.8 to 1.1 is carried out in an equivalent.

Next, the partially blocked polyisocyanate (C) of the present invention is obtained by reacting a part of the isocyanate group of any polyisocyanate compound containing two or more isocyanate groups with a monophenol. Compounds having an average of about one free reactive isocyanate group are used.

As the above polyisocyanate compound,
Aliphatic polyisocyanates such as trimethylene isocyanate, tetramethylene isocyanate, pentamethylene isocyanate, hexamethylene isocyanate, ethylidene isocyanate, butyridine isocyanate,
1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,2-cyclohexane diisocyanate, cycloalkylene diisocyanate such as isophorone diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-
Diphenyl diisocyanate, aromatic diisocyanate such as 1,5-naphthalenediisocyanate, 4,4′-diphenylenemethane diisocyanate, 2,4-ditoluene diisocyanate, 2,6-ditoluene diisocyanate,
Or an aliphatic-aromatic isocyanate such as a mixed diisocyanate thereof, a dimer or trimer modified product of toluene diisocyanate, a polyfunctional isocyanate such as a dimer or trimer modified product of hexamethylene diisocyanate, a polyol such as glycerin, trimethylolpropane, or pentaerythritol. , Polyether polyols, polyester polyols and the like, and isocyanate group-containing prepolymers derived from the above polyisocyanates.

The monophenols serving as a blocking agent for the polyisocyanate compound preferably have a molecular weight of 90 to 600. As such monophenols, phenol, nonylphenol, α-naphthol,
Examples include β-naphthol, p-tert-octylphenol, ethylphenol, styrenated phenol, cresol, xylenol, nitrophenol, chlorophenol and the like.

In the reaction between the polyisocyanate compound and the blocking agent, the reaction ratio is adjusted so that the number of free-reactive isocyanate groups in the resulting partially blocked polyisocyanate (C) becomes about one. The reaction is preferably carried out at 80 to 100 ° C. in the presence of a tertiary amine catalyst.

When the viscosity of the reaction system is high, an appropriate solvent is preferably used. Examples of such a solvent include those which are inert to free isocyanate groups and are soluble in water, such as ethyl acetate and acetic acid. Butyl, cellosolve acetate, methyl ethyl ketone, dimethylformamide, dioxane and the like are preferred.

By reacting the thus obtained partially blocked polyisocyanate (C) with the above-mentioned phosphorus-containing epoxy resin-amine adduct (B), the baking according to the present invention is carried out.
A resin for mold coating is obtained.

In this reaction, one equivalent of active hydrogen of the phosphorus-containing epoxy resin-amine adduct (B) is added to all isocyanate groups (free isocyanate group and blocked isocyanate group) of the partially blocked polyisocyanate (C). Group) is 0.2 to 1.0 equivalent (preferably 0.6 to 0.1 equivalent).
It is preferable to carry out the reaction at a ratio of (8 equivalents).

By neutralizing the amino group in the obtained baking-type coating resin with an acid, a water-soluble baking-type water-soluble coating resin can be obtained.

As the acid used here, acetic acid, formic acid,
Organic acids such as propionic acid and lactic acid are exemplified. The amount of the acid used is 1.0 to 1.2 equivalents to 1 equivalent of the amino group in the baking type coating resin, and neutralized with ion exchanged water so that the nonvolatile content becomes 20 to 40%. At this time, pH 4
To ~ 6 .

[0030]

The baking type water-soluble coating resin of the present invention comprises:
It can be cured at a low temperature of 80 to 100 ° C, and has extremely good storage stability at a temperature of 50 ° C or less. Therefore, metal, slate board, mortar board, and various plastics can be used as they are in the form of clear or colored with coloring agents such as pigments and dyes by spraying, brushing, electrodeposition coating, dip coating, etc. , Can be used as a low-temperature baking type coating agent for thermoplastic materials such as rubber.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples and Examples, but the present invention is not limited to these Examples.

Production Example 1 Preparation of Phosphorus-Containing Epoxy Resin-Amine Adduct "Adekaresin EP-4100" (bisphenol A epichlorohydrin type epoxy resin manufactured by Asahi Denka Kogyo Co., Ltd.) having an epoxy equivalent of 190 was added to 190 parts (parts by weight, hereinafter the same). 38 parts of monoethyl phosphate were blended and stirred at 130 ° C. for 3 hours to obtain a phosphorus-containing epoxy resin (A-1). The epoxy equivalent was 770.

Thereafter, 30 parts of diethanolamine and 110 parts of cellosolve acetate were added and reacted at 100 ° C. for 2 hours to obtain a phosphorus-containing epoxy resin-amine adduct (B-B) having a nonvolatile content of 70%.
1) was obtained.

Production Example 2 Preparation of Phosphorus-Containing Epoxy Resin-Amine Adduct "ADEKARESIN EP-5100" (bisphenol A epichlorohydrin type epoxy resin manufactured by Asahi Denka Kogyo Co., Ltd.) having an epoxy equivalent of 500, and 5 parts of monomethyl phosphate mixed with 500 parts And stirred at 80 ° C. for 3 hours to obtain a phosphorus-containing epoxy resin (A-
2) was obtained. The epoxy equivalent was 580.

Thereafter, N-methylethanolamine
65 parts and 245 parts of cellosolve acetate were added, and at 100 ° C., an additional 3 parts were added.
The reaction was carried out for 70 hours to obtain a phosphorus-containing epoxy resin-amine adduct (B-2) having a nonvolatile content of 70%.

Production Example 3 Preparation of Phosphorus-Containing Epoxy Resin-Amine Adduct "Adekaresin EP-4901" (bisphenol F epichlorohydrin type epoxy resin manufactured by Asahi Denka Kogyo Co., Ltd.) having an epoxy equivalent of 175, 50 parts of bisphenol A, and dimethyl After mixing 2 parts of benzylamine and reacting at 150 ° C. for 5 hours, 10 parts of monosodium phosphate was mixed and stirred at 120 ° C. for 5 hours to obtain a phosphorus-containing epoxy resin (A-3).
The epoxy equivalent was 1250.

Thereafter, 20 parts of diethanolamine and 110 parts of cellosolve acetate were added, and the mixture was further reacted at 100 ° C. for 3 hours to obtain a phosphorus-containing epoxy resin-amine adduct (B-3) having a nonvolatile content of 70%.

Production Example 4 Preparation of phosphorus-containing epoxy resin-amine adduct To 240 parts of hydrogenated bisphenol A type epoxy resin having an epoxy equivalent of 240, 10 parts of phosphoric acid was mixed and reacted at 60 ° C. for 3 hours. Resin (A-4) was obtained. The epoxy equivalent was 1050.

Thereafter, N-methylethanolamine
30 parts and 120 parts of ethyl acetate were added, and the mixture was further reacted at 80 ° C. for 3 hours to obtain a phosphorus-containing epoxy resin-amine adduct (B-4) having a nonvolatile content of 70%.

Production Example 5 Preparation of Phosphorus-Containing Epoxy Resin-Amine Adduct “ADEKARESIN EP-4000” having an epoxy equivalent of 320 (epoxy resin of bisphenol A propylene oxide adduct manufactured by Asahi Denka Kogyo KK) 320 parts of bisphenol A 5
Five parts were mixed and reacted at 150 ° C. for 5 hours to obtain an epoxidized product having an epoxy equivalent of 750. Further cellosolve acetate
180 parts were added, the temperature was cooled to 80 ° C., 13 parts of monosodium phosphate was blended, and the mixture was stirred at 80 ° C. for 3 hours to obtain a phosphorus-containing epoxy resin (A-5). The epoxy equivalent was 1400.

Thereafter, 30 parts of diethanolamine was added to
The mixture was reacted at 80 ° C. for 3 hours to obtain a phosphorus-containing epoxy resin-amine adduct (B-5) having a nonvolatile content of 80%.

Production Example 6 Preparation of partially blocked polyisocyanate 174 parts of 2,4-toluene diisocyanate and phenol
96 parts, 5 parts of dimethylbenzylamine and 118 parts of ethyl acetate were added, and the mixture was stirred and reacted at 80 ° C. for 3 hours under nitrogen.
%, NCO% 10.6 to obtain a partially blocked polyisocyanate (C-1).

Preparation Example 7 Preparation of Partially Blocked Polyisocyanate 100 parts of 2,4-toluene diisocyanate prepolymer “Coronate L” (manufactured by Nippon Polyurethane Co., Ltd.) of trimethylolpropane having an NCO% of 13.3 and a non-volatile content of 75% , Nonylphenol (44 parts), dimethylbenzylamine (5 parts), and cellosolve acetate (65 parts) were added, and the mixture was stirred and reacted at 80 ° C. for 3 hours under nitrogen to obtain a partially blocked polyisocyanate (C-2) having a nonvolatile content of 70% and an NCO% of 20%. ) Got.

Example 1 70 parts of the phosphorus-containing epoxy resin-amine adduct (B-1) obtained in Production Example 1 and 30 parts of the partially blocked polyisocyanate (C-1) obtained in Production Example 6 At 80 ° C for 4 hours,
After stirring and reacting, it was confirmed by infrared scanning that absorption of NCO groups had completely disappeared. Then mix 3 parts of acetic acid,
It was further diluted with ion-exchanged water to obtain a baking type water-soluble coating resin of the present invention having a nonvolatile content of 25% and a pH of 4.1.

The aqueous clear resin thus obtained was treated with sandpaper (# 360) and then degreased with acetone according to JIS G
It was applied on a −3141 steel plate and baked at 80 ° C. for 30 minutes to obtain a coating film. Table 1 shows the test results of the coating film performance.

Example 2 70 parts of the phosphorus-containing epoxy resin-amine adduct (B-2) obtained in Production Example 2 and 30 parts of the partially blocked polyisocyanate (C-1) obtained in Production Example 6 Was mixed and the same operation as in Example 1 was performed to obtain a coating film. The test results of the coating film performance are shown in Table 1.

Example 3 70 parts of the phosphorus-containing epoxy resin-amine adduct (B-3) obtained in Production Example 3 and 30 parts of the partially blocked polyisocyanate (C-1) obtained in Production Example 6 Was mixed and the same operation as in Example 1 was performed to obtain a coating film. The test results of the coating film performance are shown in Table 1.

Example 4 60 parts of the phosphorus-containing epoxy resin-amine adduct (B-4) obtained in Production Example 4 and 40 parts of the partially blocked polyisocyanate (C-2) obtained in Production Example 7 After the mixture was mixed, the same operation as in Example 1 was carried out, and the reaction was carried out until the isocyanate group was completely eliminated. Then, 2.2 parts of formic acid was added, and the mixture was further diluted with ion-exchanged water so that the nonvolatile content became 25%. The pH of the aqueous solution was 4.5. Further, the same operation as in Example 1 was performed to obtain a coating film. The test results of the coating film performance are shown in Table 1.

Example 5 60 parts of the phosphorus-containing epoxy resin-amine adduct (B-5) obtained in Production Example 5 and 40 parts of the partially blocked polyisocyanate (C-2) obtained in Production Example 7 After mixing, the same operation as in Example 4 was performed to obtain a coating film. The test results of the coating film performance are shown in Table 1.

Comparative Example 1 "ADEKARESIN EP-5100" having an epoxy equivalent of 500 (bisphenol A epichlorohydrin type epoxy resin manufactured by Asahi Denka Kogyo KK) was mixed with 500 parts of N-methylethanolamine.
70 parts and 245 parts of cellosolve acetate were added, and the mixture was stirred at 100 ° C. for 3 hours to obtain an epoxy resin-amine adduct having a nonvolatile content of 70%.

70 parts of the above epoxy resin-amine adduct,
30 parts of the partially blocked polyisocyanate (C-1) obtained in Production Example 6 was mixed, and a coating film was obtained in the same manner as in Example 1. Table 1 shows the test results of the coating film performance.

Comparative Example 2 500 parts of "ADEKARESIN EP-5100" (bisphenol A epichlorohydrin type epoxy resin manufactured by Asahi Denka Kogyo Co., Ltd.) having an epoxy equivalent of 500 were added to N-methylethanolamine.
70 parts and 245 parts of cellosolve acetate were added, and the mixture was stirred at 100 ° C for 3 hours to obtain an epoxy resin-amine adduct having a nonvolatile content of 70%.

Separately, 2,4-toluene diisocyanate 1
74 parts, phenol 200 parts, dimethylbenzylamine 5
Parts, 160 parts of ethyl acetate, and at 80 ° C. for 8 hours under nitrogen,
After stirring and reacting, it was confirmed by infrared scanning that absorption of NCO groups was completely eliminated, and a fully blocked isocyanate compound was obtained.

70 parts of the above epoxy resin-amine adduct,
30 parts of a fully blocked isocyanate compound and 1.8 parts of acetic acid are mixed, diluted with ion-exchanged water, and a nonvolatile content of 25%, pH 5.
An aqueous solution of 5 was obtained.

Thereafter, a coating film was obtained in the same manner as in Example 1. The test results of the coating film performance are shown in Table 1.

Comparative Example 3 174 parts of 2,4-toluene diisocyanate, 72 parts of methylethylketoxime, 5 parts of dimethylbenzylamine and 107 parts of ethyl acetate were added, and the mixture was stirred and reacted at 80 ° C. for 3 hours under nitrogen to form a partial block. An isocyanate compound was obtained.

70 parts of the epoxy resin-amine adduct prepared in Comparative Example 1, 30 parts of the above partially blocked isocyanate compound and 2.2 parts of acetic acid were mixed and diluted with ion-exchanged water.
An aqueous solution having a nonvolatile content of 25% and a pH of 4.5 was obtained.

Thereafter, a coating film was obtained in the same manner as in Example 1. Table 1 shows the test results of the coating film performance.

Comparative Example 4 70 parts of the phosphorus-containing epoxy resin-amine adduct (B-1) obtained in Production Example 1, 30 parts of the fully blocked isocyanate compound prepared in Comparative Example 2, and 2.2 parts of acetic acid were mixed. Then, the mixture was diluted with ion-exchanged water to obtain a coating film in the same manner as in Example 1. The test results of the coating film performance are shown in Table 1.

[0060]

[Table 1]

Continuation of the front page (72) Inventor Jinichi Kanda 7-35 Higashiogu, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd. (56) References JP-A-61-130328 (JP, A) JP-A-56- 65052 (JP, A) JP-A-62-129363 (JP, A) JP-A-60-245617 (JP, A) JP-A-61-98724 (JP, A) Japanese Translation of PCT Application No. 58-500170 (JP, A) Tokio Table 60-500449 (JP, A) Tokio Table 3-502204 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 C09D 1/04 -201/10

Claims (1)

(57) [Claims] 1. A phosphate (II) having at least one active hydrogen on an epoxy group-containing resin (I) ,
Based on 1 equivalent of epoxy group of epoxy group-containing resin (I)
An amine compound (II) is added to the phosphorus-containing epoxy resin (A) obtained by the reaction so as to have an active hydrogen equivalent of 0.1 to 0.5.
I) to 1 equivalent of epoxy group of phosphorus-containing epoxy resin (A)
Phosphorus-containing epoxy resin-amine adduct (B) obtained by reacting with an active hydrogen equivalent of 0.8 to 1.1 on the other hand
And baking , after reacting the partially blocked polyisocyanate (C), with an acid to adjust the pH to 4 to 6.
Method for producing mold water-soluble coating resin.