JPH01104646A - Thermosetting type resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition, consisting of a compound or resin having >=2 glycidyl groups and a specific acrylic (co)polymer having tert-butyl ester groups and used as one-pack type stable thermosetting coatings or powder coatings. CONSTITUTION:A thermosetting type resin composition, containing (A) a compound or resin having >=2 glycidyl groups in the molecule (e.g. diglycidyl ether of bisphenol A or diglycidylaniline) in an amount of 5-95wt.% expressed in terms of solid, (B) an acrylic (co)polymer (e.g. copolymer of tert-butyl methacrylate and methyl methacrylate) having tert-butyl ester groups as pendant groups without containing glycidyl group and group (phenolic OH, amino group or aldehyde group) reactive therewith in an amount of 95-5wt.% expressed in terms of solid and used as resin vehicles of one-pack type thermosetting coatings, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a thermosetting resin composition, and more particularly to a novel resin composition for use in a one-component stable thermosetting paint or powder coating. be.

Prior Art A polymer compound having a glycidyl group, such as a glycidyl methacrylate copolymerized acrylic resin or an epoxy resin,
Thermosetting resin compositions comprising polybasic acids and polyamines are well known and are widely used in coatings and other fields. In particular, the ester bond obtained by the reaction of a glycidyl group and a carboxylic acid is strong and stable, has excellent weather resistance, chemical resistance, heat resistance, etc., and does not cause coloring, so it is suitable for paint purposes.

However, the reactivity of glycidyl groups and carboxylic acid groups is quite high, and the reaction proceeds easily even at room temperature, so if they are allowed to coexist in a solution state, the viscosity increases and gels within a few days.

Therefore, it is necessary to mix a resin or compound containing a glycidyl group and a resin or compound with a carboxyl group immediately before use to create a so-called two-part type. It is almost impossible to prepare a resin or a group of compounds containing separate groups in a one-part form. In the field of powder coatings, for example, coatings containing glycidyl methacrylate copolymer resin and dicarboxylic acid have been put into practical use, but this is because the reaction rate is slow due to the solid phase. However, even in that case, if stored for more than a few months, the reaction will gradually proceed, making it impossible to put it into practical use. In particular, if stored at high temperatures, the reaction will proceed significantly.

Problems to be Solved by the Invention Although the invention ultimately utilizes the desired reaction between glycidyl groups and carboxyl groups, it is not possible to use a one-component paint;
Alternatively, there is a need for a resin composition that can be prepared into a powder coating that can be stored stably for a long period of time and that can also be used as a two-component coating, and it is an object of the present invention to meet such problems.

Means for Solving the Problems According to the present invention, the above-mentioned object of the invention is a compound or resin having two or more glycidyl groups in the molecule, calculated as a solid content of 5 to 9.
5% by weight of an acrylic polymer or copolymer having a t-butyl ester group as a pendant group and not containing a glycidyl group or a group reactive with a glycidyl group, calculated as a solid content of 95 to 5% by weight. This can be achieved by a curable resin composition.The compounds or resins having two or more glycidyl groups in the molecule used in the present invention include various glycidyl ethers, especially glycidyl ethers of polyhydric phenols or polyhydric alcohols. Can be mentioned. These can be obtained by reacting evil chlorohydrin with desired polyhydric phenols or polyhydric alcohols in the presence of an alkali. For example, diglycidyl ether of bisphenol A, diglycidyl ether of resorcinol, triglycidyl ether of phloroglucinol, triglycidyl ether of trihydroxydibiphenyl, phenol.
Polyglycidyl ether of formaldehyde novolak, polyglycidyl ether of 0-cresol formaldehyde novolac, diglycidyl ether of butanediol, diglycidyl ether of polypropylene glycol, diglycidyl ether of neopentyl glycol, triglycidyl ether of glycerin , triglycidyl ether of trimethylolpropane,
Tetraglycidyl ether of pentaerythritol, polyglycidyl ether of pentaerythritol, and other polyfunctional epoxy compounds include diglycidyl isophthalate, diglycidyl phthalate, and diglycidyl linole trimer acid as epoxy compounds derived from aromatic dicarboxylic acids. Also included are esters and triglycidyl isocyanurate, tetraphenylolethane epoxy, and the like. Furthermore, epoxidized esters of unsaturated alcohols and polyvalent aliphatic acids, such as di(2,3-epoxyhexyl adipate), di(2,3-oxalate),
epoxybutyl), di(2,3-epoxyhexyl) succinate, di(2,3-epoxybutyl) phthalate, and nitrogen compounds containing glycidyl groups, such as diglycidylaniline, di- and triglycidylamine, etc. Can be done.

The other component in the resin composition of the present invention is an acrylic polymer or copolymer that has a t-butyl ester group as a pendant group and does not contain a glycidyl group or a group reactive with a glycidyl group. In addition, in the specification of this application, “
The term "group reactive with a glycidyl group" refers to a group that is usually pendant to an acrylic resin, and is a group that is reactive with a glycidyl group.
It means a group that reacts with a glycidyl group at a temperature of °C, and specifically includes a phenolic hydroxyl group, an amino group, an aldehyde group, a carboxyl group, etc. Such acrylic polymers or copolymers are conveniently prepared by polymerization of t-butyl acrylate or dobutyl methacrylate, or by copolymerization of t-butyl acrylate or t-butyl methacrylate-I. with monomers such as those described below.

(1) Hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, allyl alcohol, methalyl alcohol, and the like.

(2) Alkyl acrylate or methacrylate-1.
For example, methyl acrylate, methyl methacrylate, ethyl acrylate-t-, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, etc. 6(3) Polymerizable amides, such as acryl amide, methacrylic amide.

(41 Polymerizable nitrile For example, acrylonitrile, methacrylate, etc.

(5) α-olefin For example, ethylene, propylene, etc.

(6) Vinyl compound For example, vinyl acetate, vinyl propionate, etc.

(71 ditechne compound ρ1 For example, butadiene, isoprene, etc.

(8)) Polymerizable aromatic compounds such as styrene, α-methylstyrene, vinyl)-luene, t-butylstyrene, etc.

The production of such acrylic polymers or copolymers, in which these monomers are used alone or in combination, is known per se, and the details thereof will be omitted.

In the resin composition of the present invention, the above-mentioned compound or resin having two or more glycidyl groups in the molecule and the above-mentioned acrylic polymer or copolymer each have a ratio of 5 to 95:95 in terms of solid content.
It is blended in a proportion of ~5% by weight. The present inventors found that the t-butyl ester group and the glycidyl group were
They can coexist stably with each other within a high temperature range of about 150~160℃, and the normal baking temperature of acrylic resin is 170℃.
It was discovered that t-butyl ester is thermally decomposed at high temperatures of ℃ or higher, generating isobutyne gas and carboxyl groups, causing a thermosetting reaction and forming a tough coating film. The present invention was completed by determining the ratio of each constituent component of the resin composition from the viewpoints of ester thermal decomposition, thermosetting reaction, and coating film performance.

As described above, the resin composition of the present invention can be used as it is as a resin vehicle for a one-component thermosetting paint.
It is also useful as a binder resin for powder coatings. Of course, if desired, a compound having two or more active hydrogen molecules that react with glycidyl may be added to the resin composition of the present invention in a small amount, for example, up to 5 parts by weight per 100 parts by weight (solid content) of the resin composition. , it is also possible to use it as a two-component thermosetting resin composition.

The present invention will be explained below with reference to Examples. In the following, unless otherwise specified, parts and percentages are by weight.

Resin production/@11 70 parts of xylene and 20 parts of n-butanol were placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen gas introduction tube, and dropping funnel, and heated at 100° while introducing nitrogen gas.
After heating to C, the following mixture was added dropwise at a constant rate over 3 hours using a dropping funnel.

Mixture (1) t-butyl methacrylate 30 parts, methyl methacrylate 20 parts n-butyl acrylate 20 parts styrene
20 parts 2-human υxyethyl methacrylate lo part t-7 tilveroxy-2-ethylhexanoate
After dropping 1 part of the above mixture, the mixture was kept warm for 30 minutes, and a mixed solution of 0.5 parts of t-butylperoxy-2-ethylhexanoate and 10 parts of xylene was added dropwise at a uniform rate over 30 minutes.

After completion of the dropwise addition, the mixture was aged at 100° C. for 3 hours and then cooled to obtain a resin solution A. The resin solids content was 50.1%.

Resin Production Example 2 A resin solution B was obtained by reacting a mixture having the following composition in the same manner as in Resin Production Example 1. The resin solid content was 50.0%.

Mixture (2) Xylene AO part n-butanol 20 parts t-butyl methacrylate 50 parts Methyl methacrylate 20 parts n-butyl acrylate 1O part Styrene
10 parts 2-ethyl methacrylate 10 parts t-7 ethyl hexanoyl methacrylate
1.5 parts Resin Production Example 3 A resin solution C was obtained by reacting a mixture having the following composition in the same manner as in Resin Production Example 1. The resin solids content was 50.1%.

Mixture (3) xylene 80 parts n-butanol 20 parts acrylic acid
30 parts methyl methacrylate
40 parts n-butyl acrylate 30 parts t-7 tylbaroxy-2-ethylhexanoate
1.5 parts Example 1 5 parts of resin solution A obtained in Resin Production Example 1, Epotote Y
D124 (bisphenol A type diglycidyl ether manufactured by Tobu Kasei Co., Ltd.) 95 parts, methyl isobutyl ketone 9
5 parts were added and stirred thoroughly to obtain a mixed solution.

The resulting mixture was applied onto a tin plate using a bar coater and baked at 170°C and 200°C for 30 minutes, respectively. After cooling to room temperature, a rubbing test was performed with xylene and acetone. The results are shown in Table 2. Also,
Table 2 shows the results of storing the mixed solution at 40° C. for one month.

Examples 2 to 8 Using the resin temperatures MA and B obtained in Resin Production Examples 1 and 2, mixtures were prepared in the same manner as in Example 1 according to the compositions shown in Table 1, and coated on a tin plate using a bar coater. and baked at 170°C and 200°C, respectively. After cooling to room temperature, a rubbing test was performed with xylene and acetone. The results are shown in Table 2. Table 2 shows the results of storing each mixed solution at 40° C. for one month.

Example 9 180 parts of the resin solution A obtained in Resin Production Example 1, 10 parts of Evotote YH434 (4-functional polyglycidylamine manufactured by Tobu Kasei), and 10 parts of methyl isobutyl ketone were added, and a mixed solution was prepared in the same manner as in Example 1. was prepared, coated on a tin plate using a bar coater, and heated at 170°C and 2°C, respectively.
Do not bake at 00℃. After cooling to room temperature, a rubbing test was performed with xylene and acetone. The results are shown in Table 2. In addition, the results of storing the mixed liquid at 40°C for one month were
Shown in the table.

Comparative Example 1 Using the resin solution C obtained in Resin Production Example 3, a mixed solution was prepared in the same manner as in Example 1 according to the composition shown in Table 1, and coated on a tin plate using a bar coater at 170°C. and baked at 200°C for 30 minutes. After cooling to room temperature, a rubbing test was performed with xylene and acetone. The results are shown in Table 2. In addition, Table 2 shows the results of storing the mixed solution at 40°C for one month. ``Rubbing test'' Rubbing test After soaking xylene or acetone in gauze and reciprocating the film surface 100 times, the condition of the film is shown. Determine visually.

O: Good with no change Δ: Film whitening ×: Film elution 2 and storage stability The respective mixtures were stored at 40° C. for one month, and changes in viscosity after storage were measured.

Claims (1)

Scope of Claims: (A) a compound having two or more glycidyl groups in the molecule or 5 to 95% by weight in terms of resin solid content; and (B) a compound having a t-butyl ester group as a pendant group, and a glycidyl group and Acrylic polymer or copolymer containing no groups reactive with glycidyl groups, solid content equivalent: 95
~5% by weight of a thermosetting resin composition.