JPH0477519A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition useful as a molding material, etc., having high adhering strength and excellent heat and water resistances comprising an epoxy resin and a specific polyfunctional methylol phenolic resin. CONSTITUTION:The objective composition is composed of (A) an epoxy resin and (B) a polyfunctional methylol phenolic resin comprising >=95% mononuclear body and/or binuclear body of phenols having at least two methylol groups in a molecule and <=5% total amount of unreacted monomer of phenols, a compound of monomethylolated phenols and a component having at least tri- nuclear body of phenols and having <=250 number-averaged molecular weight. Besides, a mixing ratio of the components is preferably 0.3-2 as epoxy equivalent/OH equivalent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a resin composition useful for injection, casting, compression, etc. molding materials, coating materials, covering materials, structural adhesives, and the like.

(Prior Art) Conventionally, epoxy resin-phenol resin compositions have been
It is used in a wide range of applications, including molding materials for packs, coating materials for dip paints, and structural adhesives. Improvements are required in terms of shortages and workability.

(Problem to be solved by the invention) Various studies have been conducted on materials that require long-term reliability, such as molding materials, coating materials, and structural adhesives related to electronic materials. However, it has been difficult to realize a resin composition that has both heat resistance and water resistance because these properties are contradictory in some cases.

In view of the above circumstances, the present invention aims to provide a resin composition that uses an epoxy resin and a specific polyvalent methylol phenol resin and has high mechanical strength, as well as excellent heat resistance and water resistance. be.

(Means for solving problems) Namely, the present invention is a bisphenol type epoxy resin.

Novolak type epoxy resin or tetrafunctional type epoxy resin, etc., phenols and aldehydes are reacted in the presence of a basic catalyst, and two or more mononuclear bodies and/or dinuclear bodies of phenols are present in one molecule. 95% or more of the monomers have methylol groups, and unreacted phenolic monomers
- The content of methylol group in the molecule is 1 or less, and - The total content of the molecule is 3 or more phenols, and the number average molecular weight is 25% or less.
The present invention provides a resin composition comprising a polyvalent methylolphenol resin (Formula 1) having a polyvalent methylolphenol resin (Formula 1) having a polyvalent methylolphenol resin of 0 or less.

Formula 1 % Formula % When the polyvalent methylol phenol resin of the present invention with a limited molecular structure is used, a composition with excellent compatibility with epoxy resin and relatively low viscosity can be obtained, resulting in excellent workability and When carrying out a crosslinking reaction, the crosslinking density is controlled to an appropriate level, and the content of phenolic monomers, monomethylolated phenols, and dimethylene ether bonds that undergo formaldehyde and/or dehydration reactions during heat curing is extremely high. It is presumed that because the amount is small, a uniform cured product can be obtained, and that the cured product is less susceptible to changes such as hydrolysis, elution, and thermal deterioration after curing.

There are no particular limitations on the epoxy resin used in the present invention.

For example, as a diglycidyl ether type of bisphenol A, Epicote 827°828.834 manufactured by Yuka Shell Co., Ltd.
, 1001, Dow DER-330, 331, 332
, Ciba's GY-257°, Dainippon Ink Chemical Co., Ltd.'s Evicron #840°850.810. Tobu Kasei Co., Ltd. Epotote VD-115, -127, Asahi Kasei Co., Ltd. AER330
Examples include ゜331.

A typical example of a novolac glycidyl ether type epoxy resin is DEN-431, 438 manufactured by Dow Company.

There are many types of cycloaliphatic epoxy resins in the literature, but in reality, Union Carbide's ERL-
Only No. 4221 is commercially available and can also be used in the present invention.

In addition, as a special epoxy resin, Yuka Shell Co., Ltd.'s Y
A biphenyl type called X-4000 is also available.

A diglycidyl ether type epoxy resin 1 using bisphenol F and bisphenol S instead of bisphenol A, such as Epicoat 807 type manufactured by Yuka Shell Co., Ltd., can also be used.

There is also a type in which alkylene oxide is added to bisphenol A and the terminal hydroxyl group is epoxidized with shrimp chlorohydrin.

Among these, preferred epoxy resins are phenyl glycidyl ether type polyaddition homologs synthesized from bisphenol and shrimp chlorohydrin. Its general formula is, for example, as shown below: Re2 (where n = 0 to 5, R□, R is hydrogen or a methyl group) The most suitable type for the present invention is the above formula, where n is 0 to 5. It is about 3rd grade.

The phenols used in the production of the polyvalent methylol phenol resin in the present invention include alkyl and allyl phenols such as phenol, cresol, xylenol, butylphenol, and phenylphenol, which may be used alone or in combination of two or more. It can be used as

The aldehydes used in the production of polyvalent methylol phenol resin in the present invention include formaldehyde,
Examples include paraformaldehyde and acetaldehyde.

As the catalyst used for producing the polyvalent methylol phenol resin in the present invention, a basic catalyst such as an alkali metal hydroxide or an alkaline earth metal hydroxide is used.

Although various methods for producing the polyvalent methylol phenol resin of the present invention are possible, the production method proposed here uses a relatively large amount of aldehyde and catalyst and is synthesized at a low temperature. Furthermore, the polyvalent methylol phenol resin thus obtained can be subjected to a slight reaction with an epoxy resin in advance.

The blending amount of the polyvalent methylol phenol resin in the resin composition of the present invention is 0.2 to 3 with an epoxy equivalent of 10H equivalent.
, preferably 0.3-2.

If the amount of polyvalent methylol phenol resin is increased so that the value is smaller than 0.2, the cured product will become too hard and stress relaxation will not be possible, resulting in a decrease in adhesive strength. If the amount of polyvalent methylol phenol resin is reduced to more than 3, the crosslinking density becomes too low and the heat resistance deteriorates.

At this time, imidazoles and other known curing accelerators may be added.

(Example) The present invention will be explained below using examples.

Example 1 138 g of paratertiary butylphenol, 187 g of 37% formalin, and 70 g of water were placed in a flask and heated to 80°C.
Raise the temperature until the entire mixture is uniformly dissolved, and then cool to room temperature. 80 g of a 25% aqueous sodium hydroxide solution was added thereto, and the mixture was reacted at 50° C. for 5 hours.

After the reaction, a 15% aqueous sulfuric acid solution was slowly added dropwise to adjust the pH to 4, and the resulting aqueous layer containing sodium sulfate was separated and removed. Add 140g of water to this, repeat stirring, standing still, and separating the aqueous layer 4 to 5 times, and add 200g of MEK to the desalted and purified resin.
was added and dissolved, and water was removed by azeotropic distillation under reduced pressure.

As a result of analyzing the obtained polyvalent methylol para tertiary butyl phenol resin by GPC, the number average molecular weight was 2.
20, the content of paratertiary butylphenol monomer, monomethylolated mononuclear product of paratertiary butylphenol, and polycondensate of trimer or higher paratertiary butylphenol and formaldehyde was 4% or less.

Example 2 The same method as in Example 1 was followed under the conditions listed in Table 1, and the results are shown in Table 1.

Example 3 Following the same method as in Example 1, after the reaction was carried out, the catalyst was removed through an ion exchange layer, MEK was added, and water was removed by azeotropic dehydration under reduced pressure.

The results obtained are shown in Table 1.

Comparative Examples 1 to 3 138 g of paratertiary butylphenol, 187 g of 37% formalin, and 70 g of water were placed in a flask and heated to 80°C.
After the mixture was heated until the mixture was uniformly dissolved, 8 g of a 25% aqueous solution of caustic soda was added, and the mixture was reacted at 80°C for 3 hours. Thereafter, the same purification as in Example 1 was carried out to obtain a resol type paratertiary butylphenol resin. This number average molecular weight is 460, and the paratertiary butylphenol monomer and 3
The content of components with a high molecular weight higher than that of the polymer was 31%.

Hereinafter, Comparative Examples 2 and 3 were carried out according to the method described in Table 1, and the results are shown in Table 1.

Furthermore, the products obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were blended together with Epicote 828 (manufactured by Yuka Shell Co., Ltd.) so that the epoxy equivalent was approximately 10H equivalent = 1, and the Then 1 part of imidazole 2E4MZ was added and dissolved with MEK to approximately 60% solids. Put this in an aluminum cup and heat at 80℃ for 1 hour plus 15 minutes.
After heating at 0''C for 2 hours, Tg was measured by DSC.

In addition, it was applied to an aluminum plate with a thickness of 2 m/m, and after drying, the coated surfaces were pasted together, a pressure of 0.1 kg/ffl was applied, and the adhesive was heated and bonded at 80°C for 1 hour plus 150°C for 1 hour. The tensile shear strength was measured after being immersed in hot water at 200°C and 80°C for 10 days and dried.

The above results are shown in Table 2.

Table 2 Tg and adhesive strength measurement results (effects of the invention) The resin composition of the present invention has high)N adhesive strength that could not be obtained with conventional epoxy resin/curing agent combinations, and has heat resistance and A cured product with water resistance can be obtained.

Claims (1)

[Claims] In a resin composition consisting of an epoxy resin and a polyvalent methylol phenol resin, 95% of the polyvalent methylol phenol resin is mononuclear and/or dinuclear of a phenol having two or more methylol groups in one molecule. That's all,
Use a polyhydric methylol phenol resin in which the total amount of unreacted phenol monomers, monomethylolated phenols, and trinuclear or higher components of phenols is 5% or less, and whose number average molecular weight is 250 or less. A resin composition characterized by: