JP2716996B2 - Epoxy resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel epoxy resin composition. More specifically, the present invention provides curability, adhesion,
The present invention relates to an epoxy resin composition which is excellent in water resistance, elution resistance and the like and is particularly suitable for use in paints.

Conventional technology Conventionally, it has been known that epoxy resin-based paint can form a coating film having excellent adhesion, water resistance, chemical resistance, and the like.
For example, a coating composed of an epoxy resin and a phenolic resin, and a coating composed of an epoxy resin and an amino resin are used for adhesiveness to a metal substrate, flexibility to withstand processing, water resistance,
Because of its good chemical resistance, it is widely used as a coating on the inner and outer surfaces of food and beverage cans, the inner surface of drums, the interior of chemical plants, and the outer surface of wires.

However, recently, with the diversification of applications, higher demands have been made on the performance of the coating film, especially when contacting with water or chemicals, the elution of components in the coating film not only at room temperature but also at high temperatures. It is desired that this be reduced as much as possible. Also, regarding the baking conditions at the time of processing, so far, the baking temperature was 180 to 220 ° C, and the baking temperature was 5 to 5.
Although it was 30 minutes, it is required to lower the baking temperature and shorten the baking time.

For this reason, many studies have been made with the aim of improving the coating properties of epoxy resin-based paints. (JP-A-63-36879), epoxy resin end modified with bisphenols to suppress the elution of the components (JP-A-62-275166), Japanese Patent Application Laid-Open (JP-A) No. 63-75069 proposes a resin having improved properties by using a reduced epoxy resin.

However, when a phenol aldehyde resin obtained by combining bisphenol A and a p-substituted phenol is used as a curing agent, hardening is hardly recognized in terms of suppressing component elution of the coating film, even though the curing performance is improved. When an epoxy resin terminal-modified with a bisphenol or an epoxy resin with a reduced proportion of low molecular components is used, the coating film adhesion, especially the boiling water adhesion, is inevitably reduced.

Problems to be Solved by the Invention The present invention solves such problems in the conventional epoxy resin-based paint, and can provide a coating film having excellent curability, and excellent adhesion, water resistance, and elution resistance. The purpose of the present invention is to provide an epoxy resin composition for paint.

Means for Solving the Problems The present inventor has conducted intensive studies to develop an epoxy resin composition for coatings having the above-mentioned preferable properties, and as a result, an epoxy resin component comprising an epoxy resin and a specific modified epoxy resin has been obtained. It has been found that the object can be achieved by blending a wenol resin or an amino resin at a predetermined ratio, and the present invention has been accomplished based on this finding.

That is, the present invention relates to an epoxy resin component comprising (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 a bisphenol and / or glycidol. 1 to 50 based on total amount
An epoxy resin composition comprising (C) a phenolic resin and / or an amino resin in a proportion in the range of weight%.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, the epoxy resin used as the component (A) has two or more epoxy groups in one molecule, and examples thereof include glycidyl ethers, glycidyl esters, and glycidyl esters. Examples include amines, linear aliphatic epoxides, and alicyclic epoxides. As glycidyl ethers,
Examples thereof include diglycidyl ether of bisphenol, polyglycidyl ether of phenol novolak, alkylene glycol, and diglycidyl ether of polyalkylene glycol. Examples of the diglycidyl ether of bisphenol include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrachlorobisphenol A, tetrabromo Examples of diglycidyl ethers of dihydric phenols such as bisphenol A and polyglycidyl ethers of phenol novolak include polyglycidyl ethers of novolak resins such as phenol novolak, cresol novolak, and brominated phenol novolak, alkylene glycol or polyalkylene glycol. Examples of the diglycidyl ether include polyethylene glycol, polypropylene glycol, And diglycidyl ethers of glycols such as tandiol.

Examples of the glycidyl esters include diglycidyl esters of hexahydrophthalic acid and diglycidyl esters of dimer acid.Examples of glycidylamines include tetraglycidylaminodiphenylmethane, triglycidylaminophenol, and triglycidyl isocyanate. Nurate and the like. Further, as the linear aliphatic epoxides, for example, epoxidized polybutadiene, epoxidized soybean oil and the like,
As alicyclic epoxides, for example, 3,4-epoxy-
6-methylcyclohexylmethyl carboxylate, 3,
4-epoxycyclohexylmethyl carboxylate and the like.

In the composition of the present invention, the epoxy resin used as the component (A) is not limited to these compounds, but among them, glycidyl ethers and glycidylamines are preferable, and diglycidyl of bisphenol is more preferable. Ethers are preferred, and among them, diglycidyl ether of bisphenol A is particularly preferable. The epoxy resins may be used alone or in combination of two or more.

In the composition of the present invention, the epoxy resin usually has a molecular weight in the range of 100 to 10,000. If the molecular weight is less than 100, the flexibility of the coating film is not sufficient, and if it exceeds 10,000, the adhesion of the coating film tends to decrease. The preferred molecular weight is selected in the range of 300 to 6,000.

In the composition of the present invention, as the component (B), a modified epoxy resin whose terminal is modified with a bisphenol or a modified epoxy resin whose terminal is modified with both a bisphenol and a glycidol is used. The epoxy resin whose end is modified with bisphenols is the epoxy resin whose terminal epoxy group is modified with bisphenols,
For example, in the presence of a catalyst such as an alkali metal hydroxide, a tertiary amine, a quaternary ammonium salt, imidazoles, phosphines, and a phosphonium salt, an epoxy resin and a bisphenol are usually used at a temperature in the range of 80 to 200 ° C. At
It can be produced by reacting for about 1 to 30 hours.

At this time, it is necessary to use the epoxy resin and the bisphenol in such a ratio that the molar ratio of the hydroxyl group of the bisphenol to the terminal epoxy group of the epoxy resin becomes 1 or more. Examples of the epoxy resin used in this case include those exemplified in the description of the epoxy resin of the component (A). Examples of the bisphenols include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, and tetraphenol. Examples include methylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrachlorobisphenol A, tetrabromobisphenol A, and the like. Of these, bisphenol A is preferred. In addition, these bisphenols may be used alone or in combination of two or more.

On the other hand, an epoxy resin in which the unterminated ends are sequentially modified with bisphenols and glycidols means that, as described above, the unterminated epoxy groups of the epoxy resin are knitted with bisphenols, and then the bisphenol residues in the modified epoxy resin are modified. A part or all of the hydroxyl groups are converted to glycidols by the formula (Wherein R in the formula is a substituent such as a hydrogen atom or a methyl group).

The glycidols used at this time include, for example, glycidol and 2-methylglycidol, which may be used alone or in combination of two or more.

Further, the molecular weight of the modified epoxy resin can be arbitrarily changed by controlling the ratio of the hydroxyl group equivalent of bisphenols and the epoxy group equivalent of the unterminated epoxy resin, preferably 300 to 8,000, more preferably
It is chosen in the range of 500-5,000. If the molecular weight is less than 300, the flexibility of the coating film will be insufficient, and if it exceeds 8,000, the adhesion of the coating film will be insufficient.

In the composition of the present invention, as the modified epoxy resin of the component (B), an epoxy resin whose end is modified with a bisphenol or an epoxy resin sequentially modified with a bisphenol and a glycidol may be used alone, They may be used in combination. The proportion of the epoxy resin (A) to the modified epoxy resin (B) is 5 to 95% by weight of the component (A) and 95 to 95% by weight of the component (B).
It is selected in the range of 5% by weight.

In the composition of the present invention, a phenol resin or an amino resin is used as the component (C). As the phenolic resin, for example, phenols such as phenols, cresols, ethylphenols, other alkylphenols, or bisphenols, and aldehydes such as formaldehyde and acetaldehyde are reacted in the presence of a basic catalyst. Examples of the obtained resin include alcohol-etherified phenolic resins obtained by reacting the obtained product with alcohols.On the other hand, examples of the amino resin include those obtained by reacting urea, melamine, a triazine compound with formaldehyde. Examples thereof include those obtained by reacting alcohol with ethers, and among them, phenol resin is preferable.

In the composition of the present invention, the resin of the component (C) is 1
Species may be used, or two or more may be used in combination. The compounding amount is selected in the range of 1 to 50% by weight, preferably 5 to 40% by weight based on the total weight of the composition, that is, the total weight of the components (A), (B) and (C). If the 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 decreases.

The epoxy resin composition of the present invention may be used by dissolving in a solvent, it is not necessary to use a solvent, or it may be only mixed before use, or may be precondensed, When used, it is advantageous to carry out the precondensation by dissolving in a solvent.

As the solvent, aromatic hydrocarbons, alcohols, ketones, esters, cellosolves, and the like can be used. Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, ethylbenzene and the like, and examples of the alcohol solvent include methanol, ethanol, propanol, n-butanol, pentanol, hexanol, heptanol, isopropanol and isobutanol. And the like. Further, as the ketone solvent, for example, acetone, methyl ethyl ketone,
Examples thereof include diethyl ketone, methyl isobutyl ketone, and diisobutyl ketone, and examples of the ester solvent include ethyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate. Further, examples of the cellosolve-based solvent include methyl cellosolve, ethyl cellosolve, butyl cellosolve and the like. These solvents may be used alone or in combination of two or more.

To the composition of the present invention, various additives conventionally used in epoxy paints, for example, fillers, reinforcing materials, pigments and the like can be added, if desired. Examples of the filler 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, penton, silica aerosol, lithobon, etc., as a reinforcing material, for example, glass fiber, asbestos fiber, boron fiber, carbon fiber, etc., as a pigment, for example, bengara, cadmium yellow, chrome yellow, chromium oxide, Examples thereof include cobalt blue, titanium oxide, and cobalt black. Further, other additives include, for example, coal tar, liquid rubber, silicone resin, waxes and the like.

Effect of the Invention The epoxy resin composition for a paint of the present invention comprises (A)
Since all three components (B) and (C) contribute to the curing reaction, the curability is improved, the baking temperature can be reduced, the baking time can be reduced, and unreacted components in the coating film can be reduced. Less, elution from the coating film is reduced, and the adhesion to boiling water is improved.

Thus, the epoxy resin composition of the present invention is excellent in curability, and adhesion, water resistance, since it can form a coating film excellent in elution resistance, for example, a clear paint for metals such as beverage cans, It is suitably used as a coloring paint, a wall spray material, a floor material, a printing ink composition or the like in combination with a pigment or the like.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The coating film adhesion and the elution resistance of the coating film were evaluated according to the following methods.

(1) Adhesion Adhesion under normal conditions and boiling water was determined based on the Gobang test of JIS K 5400. Adhesion to boiling water is as follows:
After soaking for a period of time, the temperature was returned to room temperature, and a Gobang eye test was performed. The numerical value indicates the number of remaining lines.

(2) Elution resistance of the coating film 100 cm ² of the coating film was put into a pressure-resistant container containing 100 ml of distilled water, and an extraction test was performed at 125 ° C. for 30 minutes. It measured and the elution resistance was calculated | required.

Reference Example 1 AER331 [Asahi Kasei Kogyo Co., Ltd., bisphenol A type epoxy resin, molecular weight 380, epoxy equivalent 189] and bisphenol A in the amounts shown in Table 1 were charged into a reactor at room temperature, and stirred to 60 ° C. After heating, a 10% by weight aqueous solution of sodium hydroxide was added thereto in an amount shown in Table 1, and then the internal temperature was gradually raised to 140 ° C. to initiate polymerization. When the viscosity of the contents increased, the internal temperature was further gradually raised to 170 ° C, and when the viscosity of the contents became constant, the contents were taken out and immediately cooled to room temperature to terminate the terminal with bisphenol A. To obtain a modified epoxy resin. The number average molecular weight is shown in Table 1.

The number average molecular weight of the obtained modified epoxy resin is
GPC (4 columns of Shodex 804, 803, 802, 802 were used in parallel) was measured.

Reference Example 2 A modified epoxy resin having a terminal modified with a bisphenol was produced in the same manner as in Reference Example 1 using the types and amounts of raw materials shown in Table 2. Table 2 shows the results.

Reference Example 3 In the same manner as in Reference Example 1, a modified epoxy resin whose terminal was sequentially modified with bisphenol A and glycidol was produced using the types and amounts of raw materials shown in Table 3. Table 3 shows the results.

Examples 1 to 6 After coating materials were prepared at the compounding ratios shown in Table 4, they were applied to an aluminum plate using a bar coater so that the thickness of the cured coating film became 10 μm, and baked at 200 ° C. for 10 minutes. Table 4 shows the evaluation results of the coating film properties.

Examples 7 to 9 Paints were prepared in the proportions shown in Table 5. A coating film test was performed on the obtained paint in the same manner as in Example 1. Table 5 shows the results.

Examples 10 to 15 Paints were prepared at the compounding ratios shown in Table 6, and the coating film was evaluated in the same manner as in Example 1. Table 6 shows the results.

Comparative Examples 1 and 2 After preparing paints at the compounding ratios shown in Table 7, the coating film was evaluated in the same manner as in Example 1. Table 7 shows the results.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C09D 163/00 C09D 163/00

Claims (1)

(57) [Claims] (1) 5-95% by weight of an epoxy resin (A) and (B)
An epoxy resin component consisting of 95 to 5% by weight of a modified epoxy resin end-modified with bisphenols and / or glycidol is added to the (C) phenolic resin or amino in a proportion of 1 to 50% by weight based on the total amount of the composition. An epoxy resin composition comprising a resin or both.