JPH02173023A - Curing agent for epoxy resin - Google Patents

Abstract

PURPOSE:To obtain a curing agent which can give a cured product improved in heat resistance and having a good balance among water resistance, moldability, etc., when used in an epoxy resin composition by using a specified polyalcohol as a component. CONSTITUTION:A curing agent of an epoxy resin comprising a polyphenol of the formula (wherein R<1> to R<6> are each H, a 1-10C alkyl or a phenyl; R<7> to R<12> are each H, a 1-4C alkyl or an alkoxy; X is Cl, or Br; a, b, c, d and e are each 0 or 1; and n is 0.5-5). The above polyphenol can be obtained by condensing a phenol with an aromatic carbonyl compound in the presence of an acid catalyst. As the aromatic carbonyl compound used, p- hydroxybenzaldehyde is particularly desirable. In order to increase the number of respective units, it is suitable to use a larger amount of the catalyst and a larger amount of the aromatic carbonyl compound. Substituents can be introduced to the obtained polyphenol by alkylation, chlorination or bromination.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a curing agent used in epoxy resin compositions used in a wide range of applications such as casting, molding, lamination, coatings, and adhesives. Regarding.

<Prior Art> Epoxy resins have excellent adhesive properties, processability, solvent resistance, etc., and are used in a wide range of applications.

However, with remarkable technological progress in recent years, higher performance, particularly heat resistance, is required in each application field.

As a method for improving the heat resistance of epoxy resin compositions,
In addition to improving the epoxy resin itself, there is a method of changing the curing agent.

As curing agents for epoxy resins, amine compounds, acid anhydrides, phenol compounds, etc. are used. Generally, when amine compounds are used, they have poor water resistance and also have toxicity problems.

In addition, acid anhydride cures slowly, and the cured product has poor water resistance.
It has the disadvantage of poor adhesion.

As a substitute for these, phenol novolaks, which have well-balanced heat resistance and water resistance, are used, particularly in the field of molding materials.

(Issues Ifi to be Solved by the Invention) Phenol tuborac-based curing agents are increasingly being used in applications where heat resistance is insufficient.

For example, currently O-
The mainstream is a system in which glycidyl ether of Talesol Novolac is cured with phenol novola 7, but recently, high heat resistance has been achieved by increasing the integration density of ICs or by dipping them in a solder bath due to surface mounting. Demand is increasing.

Means for Solving the Problems> The present invention provides a curing agent for epoxy resin consisting of a polyhydric phenol represented by the following (i) (in the formula, R1-R6
is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group.

R1-R11 are hydrogen atoms, or alkyl groups or alkoxy groups having 1 to 4 carbon atoms.

X is a chlorine atom or a bromine atom.

a, b, , c, d, e are numbers 01 or 1, and n is
It is a number from 0.5 to 5. ) Substituent Rl of polyhydric phenol represented by general formula (+)
, R& is specifically exemplified by a hydrogen atom, a methyl group,
Examples include ethyl group, propyl group, butyl group, hexyl group, nonyl group, cyclopropyl group, cyclohexyl group, and phenyl group.

Specific examples of R7-R11 include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, and a propoxy group.

The alkyl group-substituted product improves water resistance, and the halogen-substituted product provides @l flammability.

n represents the average number of repeating units and is 0.5 or more and 5 or less.

If n is less than 0.5, the effect of improving heat resistance will be small, and if n is too large, the viscosity will become too high and processability and moldability will deteriorate, which is not preferable.

The polyhydric phenol of the present invention can be obtained by condensing a phenol and an aromatic carbonyl compound over an acidic catalyst.

Specific examples of phenols include phenol, cresol, ethylphenol, propylphenol, butylphenol, hexylphenol, nonylphenol, cyclopropylphenol, cyclohexylphenol, chlorophenol, bromophenol, xylenol, methylpropylphenol, methylbutylphenol, and methylhexyl. Examples include phenol, dipropylphenol, dibutylphenol, dichlorophenol, dibromophenol, chlorcresol, bromcresol (including each isomer), and the like.

Specific examples of aromatic carbonyl compounds include hydroxybenzaldehyde, methylhydroxybenzaldehyde, methoxyhydroxyhenzaldehyde, crotonaldehyde, bromobenzaldehyde, dimethylhydroxybenzaldehyde, dichlorobenzaldehyde, dibromobenzaldehyde (including each isomer), etc. It will be done.

Among these, hydroxybenzaldehyde, particularly p-hydroxybenzaldehyde, is preferred.

These phenols and aromatic carbonyl compounds are
One type or two or more types of each can be used.

Further, small amounts of other aldehydes can also be used in combination with the aromatic carbonyl compound.

Other aldehydes include formaldehyde, acetaldehyde, crotonaldehyde, acrolein, glyoxal, and benzaldehyde.

The condensation of phenols with aromatic carbonyl compounds is carried out using well-known acidic catalysts for novolak synthesis, such as mineral acids, organic acids such as toluenesulfonic acid, zinc acetate, and the like.

In order to increase the number of repeating units, it is sufficient to increase the aromatic carbonyl compound and the catalyst.

Substituents can also be added to the thus obtained polyhydric phenol by alkylation, chlorination or bromination.

As the epoxy resin using the polyhydric phenol of the present invention as a curing agent, there are known epoxy resins! Confirm it.

For example, glycidyl ethers of diphenols such as bisphenol A1 bisphenol F1 bisphenol AD, brominated bisphenol A luzorcin, hydroquinone; phenol novolac, talesol novolanc, resollanc bora, trihydroxyphenylmethane, trihydroxyphenylpropane, tetrahydroquinone; Grindyl ethers of polyphenols such as di-diphenylethane, polyvinylphenol, polyisopropenylphenol, and the polyhydric phenol represented by the general formula (1) of the present invention; glycidylamines such as diaminodiphenylmethane and aminophenol; vinylcyclohexene These include alicyclic epoxy resins such as carbon dioxide, alicylinoxy dieboxy acetal, and alicylic diepoxycarboxylate; heterocyclic epoxy resins such as hydantoin type epoxy resins and triglycidyl isocyanurate;

The amount of the polyhydric phenol curing agent used in the present invention is such that the phenolic hydroxyl group is 0.2 to 1.5 equivalents to the glycidyl group.

In particular, in order to lower the viscosity of the composition with epoxy resin,
Use it sparingly. .

Furthermore, the composition of the curing agent and epoxy resin of the present invention includes:
If necessary, known additives such as fillers, hardening accelerators, mold retardants, flame retardants, and surface treatment agents can be added.

Transfer molding, compression molding, injection molding, etc. can be used to encapsulate semiconductors and other electronic components using the composition of the present invention, which includes a curing agent and an epoxy resin. In some cases, conventionally known molding methods such as casting, dipping, and dropping methods may be applied.

In addition, in order to use the resin composition for laminates, the resin composition is uniformly dissolved using methyl ethyl ketone, toluene, or ethylene glycol monomethyl ether, and glass fibers or organic fibers are impregnated with this, and then heated and dried. , prepreg, and press molding this.

(Effects of the Invention) By using the epoxy resin composition using the specific curing agent of the present invention, it is possible to obtain a cured molded product with high heat resistance, which has not been obtained so far, and a well-balanced water resistance, moldability, etc. can.

(Example> The present invention will be explained below with reference to Examples.

The average molecular weight and average number of repeating units were measured using a gel permeation chromatograph (manufactured by JASCO Corporation, TRIRO).
It was measured and calculated using TAR SR-■).

Evaluation of the cured molded product is as follows.

Glass transition temperature thermomechanical analyzer (T made by Daini Seikosha)
MA10 type).

Reference examples 1 to 6, comparative reference examples! In a reactor equipped with a thermometer, stirrer, and condenser, the phenols listed in Table 1, 122 g of p-hydroxybenzaldehyde, and p-toluenesulfone full (
-Water (m) 3.8 g 9 The reaction was allowed to proceed for 6 hours under stirring and reflux at 5 to 105°C.

Subsequently, the mixture was neutralized in a 10% aqueous sodium hydroxide solution, washed with water five times, and distilled to remove unreacted monomers to obtain polyhydric phenol.

The average number of repeating units of this polyhydric phenol was measured. The results are shown in Table 1.

Reference Example 7 Polyhydric phenol was obtained in the same manner as Reference Example 1 except that 188 g of phenol was replaced with 141 g of phenol and 54 g of m-cresol.

The average number of repeating units was 2.7.

Reference Example 8 In a reaction vessel similar to Reference Example 1, 246 g of 3-methyl 6t-butylphenol, 54 g of O-cresol, and 3.8 g of p-toluenesulfonic acid hydrate were mixed at 95 to 105°C with stirring for 36 g. After dropping 16.7 g of % formalin over 1 hour, the mixture was kept warm for 1 hour.

Subsequently, 97.6 g of p-hydroxybenzaldehyde was added and reacted for 5 hours.

Thereafter, the same post-treatment as in Reference Example 1 was performed to obtain polyhydric phenol.

The average number of repeating units was 2.2.

Table Examples 1 to 8, Comparative Example 1.2 As the epoxy resin, glycidyl ether of O-cresol novolak (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumiepoxy 6ESCN-195, epoxy equivalent 1.95) 195
g, various polyhydric phenols shown in Table 2 as a curing agent, triphenylphosphine as a curing accelerator, and fused silica (FS-891 manufactured by Denki Kagaku Kogyo ■) as a filler in the amounts shown in Table 2, and rolled. After heating and kneading at 175℃
Press molding was performed for 5 minutes.

Further, the product was subjected to bost kinearing in an oven at 180° C. for 5 hours to obtain a cured molded product.

The glass transition temperature of this cured molded product was measured.

The results are shown in Table 2.

Table: Product name Tamanol, softening point 95°C) Examples 9 to 12, Comparative Example 3.4 As the epoxy resin, bisphenol A type liquid epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., product name Sumiepoxy ■ELA-
070, 188 g of epoxy [188], various polyhydric phenols synthesized in Reference Examples and Comparative Reference Examples as a curing agent and shown in Table 3, curing 1iIJI, 2-methyl 4-methyl imitasol in the amount shown in Table 3 were blended and cast molded at 100°C for 1 hour and then at 150°C for 4 hours to obtain a cured molded product.

The glass transition temperature of this cured product was measured.

The results are shown in Table 3.

Claims (1)

[Claims] A curing agent for epoxy resin comprising a polyhydric phenol represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1 to R^6 are hydrogen atoms, carbon numbers 1 to 10
It is an alkyl group up to or a phenyl group. R^7~R^1^2 are hydrogen atoms or carbon atoms 1 to 4
These are alkyl groups and alkoxy groups. X is a chlorine atom or a bromine atom. a, b, c, d, e are numbers 0 or 1, and n is 0
．． The number is 5-5. )