JPS6295315A - One-pack type curable epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide the titled composition containing an epoxy resin, a specific imidazole compound as a curing agent and a specific phosphonium salt as a cure accelerator, having excellent storage stability and curability and giving a cured product having high glass transition temperature. CONSTITUTION:The objective one-pack type epoxy resin composition can be produced by compounding (A) 100pts.(wt.) of an epoxy resin, preferably a liquid glycidyl ether derived from a polyhydric alcohol such as bisphenol A, etc., with (B) 1-10pts. of an imidazole compound selected from the compound of formula I (n is 1-14; R<1>-R<3> are H, alkyl or phenyl) and formula II (R' is H, methyl or hydroxymethyl; R'' is alkyl or phenyl) and (C) 0.005-1pt. of a phosphonium salt such as triethylbenzyl phosphonium chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention The present invention relates to a one-component curable epoxy resin composition that has excellent storage stability and curability and provides a cured product with a high positive transition temperature.

(Industrial Application Field) The epoxy resin composition of the present invention is used for various purposes, particularly for casting of electrical and electronic components, botting,
It can be advantageously used for insulation sealing, etc.

(Conventional technology) Epoxy resin has excellent electrical insulation, adhesive properties, moisture resistance, etc.
Moreover, considering that the shrinkage during curing is small, electrical parts,
It is widely used for insulation sealing of semiconductor elements, integrated circuits, etc.

Conventionally, polyamines, organic dibasic acid anhydrides, phenolic resins, etc. have been used as curing agents for epoxy resins, but these curing agents have a usable life of only a few minutes when mixed with epoxy resins. Since the curing agent is only a few days long, it is used as a curing agent for so-called multi-component epoxy resins, in which the epoxy resin and curing agent are stored separately and mixed immediately before use. However, multi-component epoxy resin
It requires preliminary dispersion, weighing, mixing, etc. during use, and has the disadvantage of poor workability.

In addition, as a latent curing agent for dispersible epoxy resin,
Typical examples include amine complexes of three types of borohydrides, and non-andiamides.

And, the amine complex of boron trifluoride provides an epoxy resin composition with a pot life of several months, and the 4-oxy resin composition cures quickly at 120-150 °C, but the amine complex during curing It is undesirable for casting and sealing electronic parts because it easily generates gas and contaminates, for example, semiconductor elements.

When used alone, dicyanamide requires a high curing temperature of 170° C. or higher. In addition, imidazole-based compounds are known as curing accelerators for dicyanamide, but non-ancyamide curing agents generate significant heat, decompose the curing accelerator, generate gas, and contaminate semiconductor devices. When curing with a thin film, the curing properties are poor.

(Node to be solved by the invention) The present invention provides a one-component curable epoxy resin composition that has excellent storage stability, a long pot life, excellent curability, and provides a cured product with a high glass transition temperature. It tries to provide something.

(b) Structure of the Invention (Means for Solving the Problems) As a result of various studies in order to solve the above problems, the present inventors have discovered that a specific imidazole compound is used as a curing agent, and By using a specific phosphonium salt as a curing accelerator, this objective could be easily achieved.

That is, the one-component curable epoxy resin composition of the present invention comprises (A) an epoxy resin, (B) a curing agent of the general formula % (1) (where n represents an integer of 1 to 14, R1, R2, and R each represent a hydrogen atom, an alkyl group, or a phenyl group. and R" represents either an alkyl group or a phenyl group.] and (C) a phosphonium salt as a curing accelerator. It is something to do.

Various kinds of epoxy resins can be used as the epoxy resin (A) in the present invention. For example, glycidyl ethers of polyhydric phenols such as bisphenol A, bisphenol F, phenol nogera, resin, and cresol novolac resin;
Glycidyl ethers of alcohols such as butane nol, polyethylene glycol, and polypropylene glycol; glycidyl esters of carboxylic acids such as phthalic acid, inphthalic acid, and tetrahydrophthalic acid; aniline,
Epoxy resins such as diaminodiphenylmethane in which the active hydrogen bonded to the nitrogen atom is replaced with a glycizol group; epoxidized products such as aminophenol; alicyclic resins such as vinylcyclohexenezoepoxide obtained by epoxidizing the olefin bond in the molecule with peracid, etc. Examples include molded epoxy resin. Particularly preferred epoxy resins are liquid glycidyl ethers derived from polyhydric phenols such as bisphenol A and bisphenol F.

Examples of the imidazole compound represented by the general formula CB of the curing agent (B) in the present invention include 2,
4-diamino-6-(2'-methylimidazole-(1
'))-ethyl-3-triazine and incyanuric acid adduct (containing water of crystallization), and the like.

Further, as the imidazole compound represented by the general formula (B2), for example, 2-phenyl-4-methyl-
5-hydroxymethylimidazole, 2-7 enyl-4
, 5-dihydroxymethylimidazole and the like.

Even if it is an imidazole compound, the general formula (B1)
Alternatively, when an imidazole compound other than (B2) is used as a curing accelerator, the storage stability of the epoxy resin composition is low and it is difficult to use it as a molding composition.

The general formula (B) and/or (B2) in the present invention
) The blending ratio of the curing agent is 10% of the epoxy resin.
0! It is usually 1 to 10 parts by weight. If the blending ratio is too small, the curability will be poor, and if it is too large, the storage stability will be poor and the usable life will be shortened.

Examples of the phosphonium salt represented by the above general formula of the curing agent accelerator (C) in the present invention include triethylpencylphosphonium chloride, tetra-n-butylphosphonium chloride, tetra-n-butylphosphonium bromide, and tetra-n-butylphosphonium Iodite, Tri-N-Kimbutylmethylphosphonium iodite, )! J-n-butylallylphosphonium bromide, tri-n-butylpene solphosphonium chloride, tetra-n-butylphosphonium-0,0-diethylphosphoro-dithiony),) IJ-n-butylhexadecylphosphonium bromide,) +) -n-octylethylphosphonium bromide, tris-2-cyanoethylallylphosphonium chloride, ethylene bistris(2-cyanoethyl)phosphonium bromide, and the like.

The blending ratio of the phosphonium salt as a curing accelerator in the present invention is usually 0.0 parts by weight per 100 parts by weight of the epoxy resin.
Place about 0.5 to 1 part by weight. If the blending ratio of the phosphonium salt is too small, the curing speed will be slow, and if it is too large, the storage stability will be poor and the usable life will be shortened.

The resin composition of the present invention may further contain various additives depending on the intended use.

For example, zircon, silica, fused silica glass, alumina, aluminum hydroxide, glass powder, calcium silicate,
Calcium carbonate, magnesium oxide, magnesium hydroxide, zirconium silicate, clay, kaolin, talc,
Fillers such as iron powder, copper powder, mica, asbestos, silicon carbide, boron nitride, molybdenum disulfide, lead compounds (for example, lead oxide), and zinc white can be blended.

In addition, epoxysilane, vinylsilane, aminosilane,
? Coupling agents such as oran compounds, alkoxy titanate compounds, and aluminum chelate compounds, and flame retardants such as antimony compounds, phosphorus compounds, and halodane compounds can be blended.

The epoxy resin composition of the present invention includes each component (A) and (B).
Although there are some differences depending on the type and combination of (C) and (C), in general, without impairing curability or cured physical properties,
It can be stably stored at room temperature for about 1 to 3 months, and can be cured quickly (for example, in 30 minutes to 3 hours) by heating at a relatively low temperature of about 100 to 150°C. There is no risk of generating gas or the like during curing, and the glass transition temperature of the cured product is approximately 140 to 160°C, which is extremely high.

The epoxy resin composition of the present invention can be used for electrical parts, electronic parts,
For example, transformers, reed relays, motors, capacitors, resistors, and hybrid ICs.

It can be advantageously used for casting, potting, insulating sealing, etc. of diodes, etc. At that time, it has extremely good workability because it is liquid-molded and has a fast curing speed.

(Examples, etc.) The following is a more detailed description of Examples and Comparative Examples.

Example 1 Ebisu type epoxy resin with epoxy equivalent of 190 (Yuka Shell Epoxy Co., Ltd. trade name Ebico-828) 1
00 parts by weight, 2,4-zoamino-6-
(2'-methyl-imidazolyl-(1')l-ethyl-
Add 4 parts by weight of an adduct of trianone and incyanuric acid (Shikoku Kasei Co., Ltd. trade name 2MA/0K) and 0.1 part by weight of triethylbennorphosphonium bromide as a curing accelerator, and after premixing, mix well with three rolls. A mold-curable epoxy equivalent was prepared by kneading and then degassing under reduced pressure.

Example 2 In place of the curing agent in Example 1, 2-phenyl-4-
A one-component curable epoxy resin composition was prepared in the same manner as in Example 1 except that 4 parts by weight of methyl-5-hydroxymethylimidazole (trade name 2P4M, manufactured by Shikoku Kasei Co., Ltd.) (Z) was used.

Example 3 Instead of the curing accelerator in Example 1, 0.1 part by weight of tri-n-butylallylphosphonium chloride was used,
A one-component curable epoxy resin composition was otherwise prepared in the same manner as in Example 1.

Example 4 A one-component curable epoxy resin composition was prepared in the same manner as in Example 3, except that 2-phenyl-4,5-dihydroxymethylimidazole was used as a curing agent instead of the curing agent in Example 3. did.

Comparative Example 1 In place of the curing agent in Example 1, 2-ethyl-4-methylimidazole (Shikoku Kasei Co., Ltd. trade name 2) was used as a curing agent.
A one-component curable epoxy resin composition was prepared in the same manner as in Example 1 except that E4MZ) was used.

Comparative Example 2 In place of the curing agent in Example 1, 2-phenylimidazole incyanur was used as a curing agent (Shikoku Kasei Co., Ltd. trade name 2PZ-OK), and the other conditions were as in Example 1.
A one-component curable epoxy resin composition was prepared in the same manner.

The molding curable resin compositions prepared in each of the above Examples and Comparative Examples were tested for dulling time, glass transition temperature, and pot life using the methods described below. The results are shown in Table 1.

([) Dulling time 1 g of the curable epoxy resin composition was collected on a hot plate kept at 130° C., and the time until the resin lost its thermodynamic properties was measured, which was determined as the dulling time.

(1j) Glass transition temperature curable epoxy resin composition? A sample cured by heating at 150° C. for 2 hours was measured using a differential scanning calorimeter (Model 910 manufactured by DuPont).

c:i) Pot life The curable epoxy resin composition was placed in a container, the viscosity was measured every day, and the pot life was defined as the time until the viscosity reached twice the initial viscosity.

As is clear from Table 1, the epoxy resin compositions of the Examples have excellent curability, have a longer usable life, and have a higher glass transition temperature of the cured product than the resin compositions of the Comparative Examples.

(e) Effects of the Invention The one-component curable epoxy resin composition of the present invention has excellent storage stability, a long pot life, excellent curability, and quickly cures by heating at a relatively low temperature, and is highly curable. The glass transition temperature of a substance is high.

Claims (1)

[Claims] 1) (A) Epoxy resin, (B) Curing agent, general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, n represents an integer from 1 to 14, R^1, R^2,
and R^3 each represent a hydrogen atom, an alkyl group, or a phenyl group. ), as well as general formulas ▲mathematical formulas, chemical formulas, tables, etc. A one-component curable epoxy resin composition characterized by containing at least one imidazole compound selected from the compounds represented by (C) a phosphonium salt as a curing accelerator.