JPH0218412A - Flexible epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain a flexible epoxy resin composition with low viscosity excellent in processability by mixing a specified epoxy resin with an aliphatic monoglycidyl ether, etc., in a specified ratio and blending a specified polyamideamine as a curing agent therewith. CONSTITUTION:With 100pts.wt. epoxy resin containing 30-60pts.wt. bisphenol A type epoxy resin having alkylene ether linkages in the main chain, 5-30pts.wt. aliphatic mono or diglycidyl ether or aromatic monoglycidyl ether (preferably butyl glycidyl ether, etc.) and a polyamideamine, i.e. a condensation reaction product between a dimer acid and a polyamine, preferably in an amount of 80-150pts.wt. are blended to provide a flexible epoxy resin composition suitable for a casting resin for electrical/electronic components and capable of providing a cured resin excellent in electric characteristics and flexibility and small variation of hardness with time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting material that has excellent flexibility, little change in hardness over time, and excellent workability.

[Conventional technology]

Conventionally, the common method for imparting flexibility to epoxy resins has been to add large amounts of plasticizers to the system, but adding large amounts of plasticizers can cause electrical properties and moisture resistance to deteriorate over time. The drawback was that long-term reliability was poor. In recent years, phenoxy resins and the like have appeared as flexible epoxy resins, but these have a drawback of high viscosity and poor workability due to their high molecular weight.

(Problems to be Solved by the Invention) An object of the present invention is to provide an epoxy resin composition that can maintain flexibility over a long period of time without deteriorating electrical properties or workability. .

[Means to solve the problem]

The present invention applies 5 to 30 M of aliphatic mono- or diglycidyl ether or aromatic monoglycidyl ether to 100 parts by weight of an epoxy resin containing 30 to 60 weight % of bisphenol A type epoxy resin containing an alkylene ether bond in the main chain. This is a flexible epoxy resin composition in which polyamide amine obtained by a condensation reaction of dimer acid and diamine is blended as a curing agent.

In the present invention, a bisphenol A type epoxy resin (hereinafter simply referred to as "flexible epoxy resin") having an alkylene ether bond in the main chain is used as a part of the epoxy resin. Such an epoxy resin reacts with a curing agent in the same way as a normal epoxy resin to give a flexible cured product. Commercially available products include Asahi Denka EP-4000.

Examples of other epoxy resins include bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, polyhydroxybenzene epoxy resin, and galboxylic acid glycidyl esters such as phthalic acid and tetrahydrophthalic acid. . These epoxy resins preferably have an epoxy equivalent of 100 to 300 and are liquid from the viewpoint of workability.

The proportion of flexible epoxy resin in epoxy resin is 30-6
It is 0% by weight. If less than 30% by weight, the aliphatic mono- or diglycidyl ether or the aromatic monoglycidyl ether is blended as a reactive diluent,
In addition to lowering the viscosity of the composition, it has the function of imparting appropriate flexibility to the cured product without substantially reducing its electrical properties. Specific examples include butyl glycidyl ether, 1,6-hexyl glycidyl ether, and phenyl glycidyl ether.

The mixing ratio of such a reaction diluent is 5 to 30 parts by weight per 100 parts by weight of the epoxy resin. If it is less than 5 parts by weight, the effect is small, and if it exceeds 30 parts by weight, it will adversely affect the electrical properties.

In the present invention, a polyamide amine obtained by a condensation reaction between a dimer acid and a polyamine is blended as a curing agent. Such polyamide amine has an amine value of 300.
~500 is preferable in terms of workability and flexibility of the cured product. Specifically, Henkel Hakusuisha's DSX-178 (
The amine value is 43 fathoms → etc.

The blending ratio depends on the type of polyamide amine and the amine value, but it is 80 to 15 parts by weight per 100 parts by weight of the epoxy resin.
0 parts by weight is usually the preferred range. If it is less than 80 parts by weight, the flexibility is excellent, but the electrical properties tend to deteriorate and the hardness changes over time.
When the amount exceeds 0 parts by weight, flexibility often tends to be poor.

(Example) Epoxy resin compositions were prepared with the formulation shown in Table 1, and the viscosity was measured.

Table EP 82B Shelling m Epoxy 1 19
0EP4000 Asahi Denka Epoxy M 32
5 Eponite 014 Alcohol monoglycidyl →
(Epoxy II 215) This composition was cured by heating at 60°C for 5 hours. The hardness (Shore deafness) of the cured product was measured at 80°C immediately after curing and after 10 days at 80°C.

The resin composition of the example has a low viscosity, and the obtained cured product has a Shore D/80°C of 25 and is highly flexible.
No change in hardness was observed even after CtO days had passed.

The resin composition of Comparative Example 1 had a Shore D/80°C of 40, and lacked flexibility.

The resin composition of Comparative Example 2 has a low viscosity and the cured product is Shore D/
Although it is very flexible at 80°C10, the cured product is sticky and the hardness changes significantly after 10 days at 80°C, lacking long-term reliability.

[Effects of the Invention] Since the present invention uses a flexible epoxy resin and polyamide amine to impart flexibility, the cured product is highly flexible and the epoxy resin exhibits little change in hardness over time. A resin composition can be obtained.

By appropriately using a reactive diluent, a resin with low viscosity and excellent workability can be obtained.

Due to the influence of the flexible epoxy resin, polyamide amine, and the reactive diluent, especially the aliphatic glycidyl ether, the overall compatibility of the composition is improved, so the reaction is uniform, there are few unreacted substances, and the cured product has good electrical properties. It is excellent;
There is also little change in hardness over time.

Claims (1)

[Claims] (1) For 100 parts by weight of an epoxy resin containing 30 to 60 parts by weight of bisphenol A type epoxy resin containing an alkylene ether bond in the main chain, 5 to 3 parts by weight of aliphatic mono- or diglycidyl ether or aromatic monoglycidyl ether
1. A flexible epoxy resin composition characterized in that a polyamide amine obtained by a condensation reaction between a dimer acid and a polyamine is blended as a curing agent.