JPH02238017A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition having excellent curability, adhesive property, water-resistance, eluation resistance, etc., and suitable for coating material by compounding a phenolic resin and an amino resin at specific ratios to an epoxy resin component composed of a specific amount of an epoxy resin and a specific amount of a modified epoxy resin. CONSTITUTION:The objective epoxy composition is produced by compounding (A) an epoxy resin component composed of (i) 5-95wt.% of an epoxy resin (preferably bisphenol A glycidyl ether having a molecular weight of 300-6,000) and (ii) 95-5wt.% of a modified epoxy resin (preferably having a molecular weight of 500-5,000) having terminals modified with a bisphenol (preferably bisphenol A) and/or a glycidol (e.g. glycidol) with (B) 1-50wt.%. preferably 5-40wt.% (based on the total epoxy resin components) of a phenolic resin and/or an amino resin (preferably phenolic resin).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel epoxy resin composition. More specifically, the present invention relates to an epoxy resin composition that has excellent curability, adhesion, water resistance, elution resistance, etc., and is particularly suitable for use in paints.

Conventional technology It has been known that epoxy resin paints form coating films with excellent adhesion, water resistance, chemical resistance, etc. For example, paints made of epoxy resin and phenolic resin,
Paints made of epoxy resins and amino resins have good adhesion to metal substrates, flexibility to withstand processing, water resistance, and chemical resistance, so they can be used on the inside and outside of food and beverage cans, on the inside of drums, and on the interior of chemical plants. It is widely used as a coating for the outer surface of wires, etc.

However, in recent years, with the diversification of applications, higher demands have been placed on the performance of coating films.Especially when coming into contact with water or chemicals, components in the coating film may elute not only at room temperature but also at high temperatures. It is hoped that this will be reduced as much as possible. In addition, regarding the baking conditions during processing, previously the baking temperature was 180°C to 220°C and the baking temperature was 5 to 30 minutes, but there is a demand for lowering the baking temperature and shortening the baking time. .

For this reason, many studies have been conducted to improve the film properties of epoxy resin paints, and so far, for example, phenol aldehyde resin, which is a combination of bisphenol A and p-[phenol], has been used as a curing agent to cure the paint. One with improved performance (Japanese Unexamined Patent Publication No. 63-36879), and one where the end of the epoxy resin is modified with bisphenols to suppress the elution of components (Japanese Unexamined Patent Publication No. 62-27516).
6), and one with improved characteristics using an epoxy resin with a reduced proportion of low-molecular components (Japanese Patent Laid-Open No. 63-7
No. 5069) and the like have been proposed.

However, although phenol aldehyde resin, which is a combination of bisphenol A and p-monosubstituted phenol, is used as a curing agent, it has little effect on suppressing the elution of components from the coating film, even though it improves curing performance. Furthermore, when using an epoxy resin terminal-modified with bisphenols or an epoxy resin with a reduced proportion of low-molecular components, coating film adhesion, especially boiling water adhesion, inevitably deteriorates.

Problems to be Solved by the Invention The present invention solves the problems with conventional epoxy resin paints, and has excellent curability, adhesion, water resistance,
The purpose of this invention is to provide an epoxy resin composition for paint that can provide a coating film with excellent elution resistance.

Means for Solving the Problems As a result of extensive research in order to develop an epoxy resin composition for paints having the above-mentioned preferable properties, the inventors have developed an epoxy resin component consisting of an epoxy resin and a specific modified epoxy resin. It has been discovered that the objective can be achieved by blending a phenol resin or an amino resin in a predetermined ratio with the resin, and based on this knowledge, the present invention has been completed.

That is, the present invention comprises (A) 5 to 95% by weight of an epoxy resin and (B) 95 to 5% by weight of a modified epoxy resin terminal-modified with bis-7 enols or glycidols or both.
1 to 1 based on the total amount of the composition to the epoxy resin component consisting of
The present invention provides an epoxy resin composition characterized in that <C> a phenolic resin, an amino resin, or both are blended in a proportion in the range of 50% by weight.

The present invention will be explained in detail below.

In the composition of the present invention, the epoxy resin used as component (A) has two or more epoxy groups in one molecule, such as glycidyl ethers, glycidyl esters, glycidyl Examples include amines, linear aliphatic epoxides, and alicyclic epoxides. Examples of the glycidyl ethers include diglycidyl ether of bisphenol, polyglycidyl ether of phenol novolak, and diglycidyl ether of alkylene glycol or polyalkylene gelylcol. Examples of the diglycidyl ether of bis7enol include bisphenol A1 bisphenol F, bisphenol AD, bisphenol S1 tetramethylbisphenol A, tetramethylbisphenol F1 tetramethylbisphenol AD, tetramethylbisphenol S1 tetramethylbisphenol A, and tetrabromobisphenol A. Examples of diglycidyl ethers of dihydric phenols such as phenol nopolak include polyglycidyl ethers of novolac resins such as 7-enol nopolak, talezol novolac, and brominated phenol nopolak, alkylene glycol or Examples of diglycidyl ethers of polyalkylene gelcols include diglycidyl ethers of glycols such as polyethylene glycol, polypropylene glycol, and butanediol.

Examples of the glycidyl esters include diglycidyl ester of hexahydrophthalic acid and diglycidyl ester of dimer acid, and examples of the glycidyl amines include tetraglycidyl amino diphenylmethane, triglycidylaminophenol, and triglycidyl isocyanate. Examples include nurate. moreover,
Examples of linear aliphatic epoxides include epoxidized polybutadiene and epoxidized soybean oil, and examples of alicyclic epoxides include 3,4-epoxy-6
-Methylcyclohexylmethyl lupoxylate, 3,
Examples include 4-epoxycyclohexylmethylcarpoxylate.

In the composition of the present invention, the epoxy resin used as component (A) is not limited to these compounds, but among these, preferably glycidyl ethers and glycyl amines, more preferably diglycidyl bisphenol. Among these ethers, diglycidyl ether of bisphenol A is particularly preferred. Further, each of the epoxy resins may be used alone, or two or more types may be used in combination.

In the composition of the present invention, the epoxy resin usually has a molecular weight of 100 to io. A value in the range ooo is used. If the molecular weight is less than 100, the coating film will not have sufficient flexibility, and if it exceeds io, ooo, the coating film adhesion will tend to decrease. The preferred molecular weight is 300 to a.
Selected within the range ooo.

In the composition of the present invention, as the component (B), a modified epoxy resin whose ends are modified with bisphenols, and I whose ends are modified with both bisphenols and glycidols;
A modified epoxy resin is used. An epoxy resin whose ends have been modified with bisphenols is an epoxy resin whose ends have been modified with epoxy groups with bisphenols,
For example, in the presence of a catalyst such as an alkali metal hydroxide, a tertiary amine, a quaternary ammonium salt, an imidazole, a phosphine, or a phosphonium salt, an epoxy resin and a bisphenol are heated at a temperature usually in the range of 80 to 200°C. It can be produced by reacting at a certain temperature for about 1 to 30 hours.

At this time, the epoxy resin and bisphenols need to be used in such a ratio that the molar ratio of the hydroxyl groups of the bisphenols to the unterminated epoxy groups of the epoxy resin is 1 or more. In addition, examples of the epoxy resin used in this case include those exemplified in the explanation of the epoxy resin of component (A), and examples of bis-7 enols include bis-7 enol A1 bisphenol F1 bisphenol AD, bisphenol Examples include S1 tetramethylbi7.7enol A1 tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetramethylbisphenol A1, tetrabromobisphenol A, and among these, bisphenol A is preferred. Moreover, these bisphenols may be used alone or in combination of two or more types.

On the other hand, an epoxy resin in which the terminal ends are modified with bisphenols and glycidols is a method in which the terminal epoxy groups of the epoxy resin are modified with bisphenols as described above, and then the terminals in the bisphenol residues in the modified epoxy resin are modified with bisphenols. Some or all of the hydroxyl groups are replaced with the formula R O CHz C CHs (I
)OH OH (R in the formula is a hydrogen atom or a substituent such as a methyl group) modified to a glycol ether group.

At this time, examples of glycidols used include glycidol and 2-methylglycidol,
These may be used alone or in combination of two or more.

The molecular weight of this modified epoxy resin can be arbitrarily changed by controlling the ratio of the hydroxyl group equivalent of the bisphenol to the terminal epoxy group equivalent of the epoxy resin, but is preferably 300 to 8,000, more preferably 300 to 8,000. is selected in the range of 500 to 5,000. If the molecular weight is less than 300, the stiffness of the coating film will be insufficient, and if it exceeds a, ooo, the adhesion of the coating film will be insufficient, which is not preferable.

In the composition of the present invention, as the modified epoxy resin of the component (B), an epoxy resin whose ends are modified with bisphenols or an epoxy resin modified sequentially with bisphenols and glycidols may be used alone, or A mixture of them may be used. In addition, the usage ratio of the epoxy resin as the component (A) and the modified epoxy resin as the component (B) is 5 to 95% by weight for the component (A) and 95% by weight for the component (B).
-5% by weight.

In the composition of the present invention, a phenol resin or an amino resin is used as component (C). The phenolic resin is produced by reacting phenol, cresols, ethylphenols, other alkylphenols, or bisphenols with aldehydes such as formaldehyde and acetaldehyde in the presence of a basic catalyst. Examples of amino resins include the obtained resins and alkyl etherified phenol resins made by reacting these resins with alcohols.
Examples include those obtained by reacting urea, melamine, and triazine compounds with formaldehyde, and those obtained by reacting alcohols with these, and among these, phenol resins are preferred.

In the composition of the present invention, one type of resin as the component (C) may be used, or two or more types may be used in combination. In addition, the blending amount is the total amount of the composition, that is, the amount of (A) mentioned above.
1 based on the total weight of ingredients, (B) ingredients and (C) ingredients
-50% by weight, preferably 5-40% by weight. If this amount is less than 1% by weight, the coating film may not be sufficiently cured, and if it exceeds 50% by weight, the elution resistance of the coating film will decrease.

The epoxy resin composition of the present invention may be used after being dissolved in a solvent, or may be used without the use of a solvent, or may only be mixed before use, or may be precondensed.
When used, it is advantageous to carry out the precondensation in a solvent.

The solvent includes aromatic hydrocarbons, alcohols,
Ketone type, ester type, cellosolve type, etc. can be used. Examples of aromatic hydrocarbon solvents include benzene, toluene, xylene, and ethylbenzene; examples of alcohol solvents include methanol,
Examples include ethanol, n-butanol, pentanol, hexanol, heptanol, impropanol, and imptanol. Examples of ketone solvents include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and diisobutyl ketone. Examples of ester solvents include ethyl acetate, butyl acetate, methyl cellosol acetate, and ethyl cellosol. Examples include acetate, butyl cellosolve acetate, and the like. Furthermore, examples of cellosolve-based solvents include methyl cellosolve, ethyl cellosolve, and butyl cellosolve. These solvents may be used alone or in combination of two or more.

The composition of the present invention may contain various additives conventionally used in epoxy paints, such as fillers, reinforcing materials,
Pigments etc. can be added.

Examples of fillers include alumina, calcium carbonate,
Silica, calcined silica, glass powder, mica powder, carbon black, graphite, aluminum powder, iron powder, hydrated alumina, asbestos, polyethylene powder, polypropylene powder, mica, kaolin, alumina oxide, bentone, silica aerosol, litobone, etc. However, examples of reinforcing materials include glass fiber, asbestos fiber, boron fiber, carbon fiber, etc., and examples of pigments include red iron, cadmium yellow, chrome yellow, chromium oxide, cobalt blue, titanium oxide, cobalt black, etc. .

Furthermore, as other additives, e.g. Examples include coal tar, liquid rubber, silicone resin, and waxes.

Effects of the Invention The epoxy resin composition for paint of the present invention has (A) and (B)
Since all three components (C) and (C) contribute to the curing reaction, the curability is improved, the baking temperature can be lowered, and the baking time can be shortened. Elution from the membrane is reduced and boiling water adhesion is improved.

As described above, the epoxy resin composition of the present invention has excellent curability and can form a coating film with excellent adhesion, water resistance, and elution resistance. It is suitably used as colored paints containing pigments, wall spraying materials, flooring materials, or printing ink compositions.

Examples Next, the present invention will be explained in more detail with reference to examples.
The present invention is not limited in any way by these examples.

In addition, the coating film adhesion and the elution resistance of the coating film were evaluated according to the following method.

(1) Adhesion Normal state and boiling water adhesion were determined in accordance with the cross-cut test of JIS κ5400. Boiling water adhesion is determined by coating film at 100°C.
After soaking in water for 1 hour, return to room temperature and perform a cross-cut test to determine I. The numerical value indicates the remaining number of rows.

(2) Elution resistance of the coating film 100 cm of the coating film was placed in a pressure container containing 100 ml of distilled water, and an extraction test was conducted at 125°C for 30 minutes.The amount of potassium permanganate consumed in the extract was calculated. The elution resistance was determined.

Reference Example 1 AER331 [manufactured by Asahi Kasei Kogyo Co., Ltd., pisphenol A type epoxy resin, molecular weight 380, epoxy equivalent weight 1891] and bisphenol A were placed in a reactor at room temperature and heated to 60°C while stirring. After heating, a 10% by weight aqueous sodium hydroxide solution was added in the amount shown in Table 1, and then the internal temperature was gradually raised to 140'O to initiate polymerization. When the viscosity of the contents increases, the internal temperature is further gradually raised to 170°C, and when the viscosity of the contents becomes constant, the contents are taken out and quickly cooled to room temperature.
A modified epoxy resin was obtained. The number average molecular weights are shown in Table 1.

In addition, the number average molecular weight of the obtained modified epoxy resin is G
PC (columns are Shodex 804, 803,
802. (using 4 parallel products of 802).

Table 1 Reference Example 3 Using the types and amounts of raw materials shown in Table 3, a modified epoxy resin whose terminals were sequentially modified with bisphenol A and glycidol was produced in the same manner as in Reference Example 1. The results are shown in Table 3.

Reference Example 2 A modified epoxy resin whose terminal end was modified with bisphenols was produced in the same manner as in Reference Example 1 using the types and amounts of raw materials shown in Table 2. The results are shown in Table 2.

Table Examples 1 to 6 After applying all the paints in the proportions shown in Table 4, they were coated on an aluminum plate using a bar coater so that the cured film thickness was 10μ, and heated at 200°C for 10 minutes. Burnt it. Table 4 shows the evaluation results of the coating film properties.

Examples 7 to 9 Paints were prepared according to the blending ratios shown in Table 5. A coating film test was conducted on the obtained paint in the same manner as in Example 1. The results are shown in Table 5.

Table 5 Weight: 950, number average molecular weight: 1500 3) AER667: Manufactured by Asahi Kasei Industries, Ltd., bisphenol A type epoxy resin, epoxy equivalent: 1:800, number average molecular weight: 2,500 Examples 10 to 15 Paints were prepared at the compounding ratios shown in Table 6. A coating film evaluation test was conducted in the same manner as in Example 1. The results are shown in Table 6.

Note 1) AER661: Manufactured by Asahi Kasei Industries, Ltd., bisphenol A type epoxy resin, epoxy equivalent weight 450, number average molecular weight 870 2) AER664: Manufactured by Asahi Kasei Industries, Ltd., bisphenol A type epoxy resin, epoxy Comparative Examples 1 and 2 After preparing a paint with the compounding ratio shown in Table 7, Example 1
An evaluation test for the coating film was conducted in the same manner as above.

The results are shown in Table 7.

Table 7

Claims (1)

[Claims] 1 to an epoxy resin component consisting of (A) 5 to 95% by weight of an epoxy resin and (B) 95 to 5% by weight of a modified epoxy resin terminal-modified with bisphenols or glycidols or both, based on the total amount of the composition. An epoxy resin composition characterized in that (C) a phenol resin, an amino resin, or both are blended in a proportion in the range of 50% by weight.