JP2719191B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an epoxy resin composition. More specifically, the present invention relates to an epoxy resin composition which is excellent in flexibility, adhesion, water resistance and the like, and is particularly suitable for use as a coating material.

[Conventional technology]

Conventionally, it is known that epoxy resin can form a coating film with excellent adhesiveness, water resistance, chemical resistance, etc., for example, from a paint composed of an epoxy resin and a phenolic resin, or from an epoxy resin and an amino resin. The paint has good adhesion to metal substrates, flexibility to withstand processing, water and chemical resistance, so it can be used for food and beverage cans inside and outside, drums inside, chemical plant interiors, wires outside, etc. Widely used as a coating.

However, recently, with increasing use of applications, higher demands have been made on coating film performance.

In particular, applications that cause severe processing deformation to the coating film increase, and cracks and peeling occur in the conventional coating film. Therefore, improvement in the flexibility of the coating film is desired.

Therefore, many studies have been made for the purpose of improving the coating properties of the epoxy resin-based coating. So far, for example,
There have been proposed, for example, those having improved flexibility using a high molecular weight type epoxy resin and those having improved flexibility by modifying the terminals of the epoxy resin with bisphenols (JP-A-62-275166). .

However, when a high molecular weight epoxy resin is used, even if the flexibility of the coating film is improved,
The adhesion of the coating film decreases. Further, when an epoxy resin modified with a bisphenol is used, a decrease in water resistance is inevitable.

[Problems to be solved by the invention]

An object of the present invention is to solve such problems in conventional epoxy resin-based paints, and to provide an epoxy resin composition which can provide a coating film having excellent flexibility, adhesion, and water resistance. It was done.

[Means for solving the problem]

The present inventor has conducted intensive studies to develop an epoxy resin composition having the above-mentioned preferable properties, and as a result, by blending a specific modified epoxy resin with a phenol resin or an amino resin in a predetermined ratio, the purpose of the present invention is as follows. The present inventors have found that this has been achieved, and have accomplished the present invention based on this finding.

That is, the present invention is a modified epoxy resin which is a reaction product of a bisphenol-type epoxy resin, a bisphenol-based compound, and a monovalent phenol-based compound having an alkyl group having 5 to 15 carbon atoms. 80%
A modified epoxy resin (A) obtained by reacting an epoxy group with the above-mentioned monovalent phenol compound having an alkyl group having 5 to 15 carbon atoms, and a phenol resin in an amount of 1 to 50% by weight based on the total amount of the composition And at least one resin (B) selected from amino resins.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, examples of the bisphenol-type epoxy resin which is a raw material of the modified epoxy resin (A) include a resin composed of diglycidyl ether of bisphenol. Examples of the diglycidyl ether of bisphenol include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F,
Examples thereof include diglycidyl ethers of dihydric phenols such as tetramethylbisphenol AD, tetramethylbisphenol S, tetrachlorobisphenol A, and tetrabromobisphenol A.

Although not limited to resins composed of these compounds, preferred among these are resins composed of diglycidyl ether of bisphenol A. Further, bisphenol-type epoxy resins may be used alone or in combination of two or more.

In the composition of the present invention, the bisphenol-type epoxy resin preferably has a number average molecular weight in the range of 300 to 6000. If it exceeds 6,000, the subsequent reaction becomes difficult. The number average molecular weight of this bisphenol type epoxy resin is more preferably from 300 to 500.

In the composition of the present invention, examples of the bisphenol-based compound as a raw material of the modified epoxy resin (A) include the following.

For example, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S,
Examples thereof include tetrachlorobisphenol A and tetrabromobisphenol A. Of these, bisphenol A is preferable. These bisphenol compounds may be used alone or in combination of two or more.

In the composition of the present invention, the monovalent phenolic compound having an alkyl group having 5 to 15 carbon atoms, which is a raw material of the modified epoxy resin (A), refers to an alkyl group having 5 to 15 carbon atoms in a benzene nucleus of phenol. And the alkyl group may be linear or branched. If the total number of carbon atoms is 5 to 15, the number of alkyl groups bonded to the benzene nucleus of phenol may be any number in the range of 1 to 5, and the bonding position is not limited. As such, for example, p-pentylphenol,
p-hexylphenol, p-heptylphenol, p
-Octylphenol, p-nonylphenol, p-decylphenol, p-dodecylphenol, 2,6-dimethyl-4-pentylphenol, 2,6-dimethyl-4-
Octylphenol, 2,6-dimethyl-4-nonylphenol, 2-methyl-4-octylphenol, 2-methyl-4-nonylphenol and the like can be mentioned.

Of these, phenol having an alkyl group having 7 to 10 carbon atoms is preferable, and p-octylphenol and p-nonylphenol are more preferable. The monovalent phenolic compounds may be used alone or in combination of two or more. 5 carbon atoms
If it is less than 15, the flexibility of the coating film is not sufficient, and if it exceeds 15 carbon atoms, the adhesion of the coating film is reduced.

The modified epoxy resin (A) is obtained by mixing a bisphenol-type epoxy resin, a bisphenol compound and a monovalent phenol compound having an alkyl group having 5 to 15 carbon atoms with, for example, an alkali metal hydroxide, a tertiary amine, a quaternary amine. It can be produced by reacting in the presence of a catalyst such as a quaternary ammonium salt, imidazoles, phosphines, phosphonium salts and the like, usually at a temperature in the range of 80 to 200 ° C. for about 1 to 30 hours.

 Solvents can be used during manufacture.

Examples of the solvent that can be used include aromatic hydrocarbon alcohols, ketones, esters, and cellosolves. Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, and ethylbenzene, and examples of the alcohol solvent include methanol, ethanol, propanol, and n.
-Butanol, pentanol, hexanol, heptanol, isopropanol, isobutanol and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and the like. Examples of the ester solvent include ethyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, and the like. Is mentioned. 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.

In the present invention, the reaction between the bisphenol-type epoxy resin, the bisphenol-based compound and the monovalent phenol-based compound having an alkyl group having 5 to 15 carbon atoms is carried out by a high-molecular weight reaction with the bisphenol-type epoxy resin and the bisphenol-based compound, It consists of a reaction between a monovalent phenol compound having an alkyl group of 5 to 15 and an epoxy group (see Masaki Shinbo, "Epoxy Resin Handbook", Nikkan Kogyo (1987), pp. 34-36). Therefore, the molecular weight, the ratio of terminal groups, and the like can be controlled by controlling the molar ratio of each of the bisphenol-type epoxy resin, the bisphenol-based compound, and the monovalent phenol-based compound having an alkyl group having 5 to 15 carbon atoms.

The terminal of the modified epoxy resin in the present invention is a group (b) obtained by reacting an epoxy group (a) and a monovalent phenol compound having an alkyl group having 5 to 15 carbon atoms with an epoxy group.
And the ratio of (b) to ((a) + (b)) is 5 to 80%. If it is less than 5%, the flexibility of the coating film may not be sufficient, and if it exceeds 80%, the adhesion of the coating film is reduced. Preferably, it is selected in the range of 8 to 60%.

In the composition of the present invention, the modified epoxy resin (A) having a number average molecular weight in the range of 600 to 10,000 is used. If the number average molecular weight is less than 600, the flexibility of the coating film is not sufficient, and if it exceeds 10,000, the adhesiveness of the coating film tends to decrease. Preferred number average molecular weight is 1200
Selected in the range of ~ 8000.

In the composition of the present invention, a phenol resin or an amino resin is used as the resin (B). 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 an alkyl etherified phenol resin obtained by reacting the obtained product with alcohols, and an amino resin obtained by reacting, for example, urea, melamine, a triazine compound with formaldehyde. Examples thereof include those obtained by reacting alcohol with ethers, and among them, phenol resin is preferable.

One type of resin (B) may be used, or two or more types may be used in combination. The amount of the composition is the total amount of the composition,
That is, it is selected in the range of 1 to 50% by weight, preferably 5 to 40% by weight based on the total weight of the modified epoxy resin (A) and the resin (B). 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 flexibility of the coating film is reduced.

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 mixed only before use, or may be subjected to precondensation, At the time of use, it is more advantageous to dissolve in a solvent to carry out precondensation. As the solvent, the above-mentioned solvents can be used.

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, and oxidized Alumina, 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, cobalt blue, Examples include titanium oxide and cobalt black. Further, other additives include, for example, coal tar, liquid rubber, silicone resin, waxes and the like.

〔The invention's effect〕

The epoxy resin composition of the present invention gives a coating film which is excellent in flexibility and excellent in adhesion, water resistance and the like. Therefore, for example, clear paint for metals such as beverage cans,
It is suitably used as a coloring paint, a wall spray material, a floor material, or a printing ink composition using a pigment or the like in combination.

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

In addition, the bending property and adhesiveness of the coating film were evaluated by the following methods.

(1) Bendability A tin plate having a thickness of 0.2 mm was sandwiched between coating films, bent 180 degrees, and the bent portion was immersed in a copper sulfate solution to make a determination.

◎… No cracks ○… Some cracks △… Some cracks ×… Some cracks and some paint film peeling (2) Adhesion Normal and boiling water adhesion in accordance with JIS K5400 Seeking sex. The boiling water adhesion was determined by immersing the coating film in water at 100 ° C. for 1 hour, returning the coating film to room temperature, and performing a Gobang test. The numerical value indicates the number of remaining lines.

Reference Example 1 The amount of AER 331 shown in Table 1 [manufactured by Asahi Chemical Industry Co., Ltd.
Bisphenol A type epoxy resin, molecular weight 380, epoxy equivalent 189], bisphenol A and p-noniphenol were charged into the reactor at room temperature, and the mixture was stirred and heated until the contents were dissolved. After dissolution, the internal temperature was set to 60 ° C., an aqueous solution of sodium hydroxide having a concentration of 10% by weight was added thereto in an amount shown in Table 1, and then the internal temperature was gradually raised to 180 ° C. to start the reaction. After the reaction was carried out for a predetermined time, the contents were taken out and immediately cooled to room temperature 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 GP
C (column used four parallel products of Shodex 805, 804, 803, 802).

The terminal group ratio was calculated from the charged amount of the monohydric phenol and the amount of the epoxy group of the modified epoxy resin.

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

Examples 1 to 8 After coating materials were prepared at the compounding ratios shown in Table 3, they were applied to a tin plate (0.2 mm) using a bar coater so that the thickness of the cured coating film became 8 to 10 μm, and 200 ° C. For 10 minutes. Table 3 shows the evaluation results of the coating film properties.

Reference Example 3 A modified epoxy resin was produced in the same manner as in Reference Example 1, except that the raw materials having the types and amounts shown in Table 4 were used. The result is the fourth
It is shown in the table.

Comparative Examples 1 to 4 After the paints were adjusted at the compounding ratios shown in Table 5, the coating films were evaluated in the same manner as in Example 1. The result is the fifth
It is shown in the table.

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. A modified epoxy resin which is a reaction product of a bisphenol-type epoxy resin, a bisphenol-based compound and a monovalent phenol-based compound having an alkyl group having 5 to 15 carbon atoms. 80% is a modified epoxy resin (A) in which an epoxy group is reacted with the above-mentioned monovalent phenol compound having an alkyl group having 5 to 15 carbon atoms, and 1 to 50% by weight based on the total amount of the composition. An epoxy resin composition comprising an amount of at least one resin (B) selected from phenolic resins and amino resins.