JPS6244767B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an epoxy resin composition having excellent curability, heat resistance, and moisture resistance. It's where you use it.

In recent years, the development of electronic devices has been remarkable and they have been widely incorporated into home appliances, automobiles, etc. other than computers. Epoxy resin compositions such as epoxy resin molding materials and epoxy resin laminates are mainly used for insulating materials, protective materials, exterior materials, and substrates on which electronic devices are mounted. Recent requirements for electronic equipment include smaller size, lighter weight, greater resistance to environmental changes, and lower cost, as evidenced by the spread of small computers (microcomputers/personal computers), smaller VCRs, and lighter weight automobiles.

These demands include thinning and lowering the cost of insulating materials, protective materials and exterior materials for electronic devices, as well as substrates, etc. In other words, the epoxy resin compositions (molding materials, laminates) used for these applications require heat resistance, There is a growing need for improved moisture resistance and lower costs.

The present invention provides an epoxy resin composition that satisfies these requirements and has heat resistance, moisture resistance, and fast curing properties.

Conventional epoxy resins include bisphenol A-type epoxy resins (for example, oil-based shell epoxy
828, 1001, 1004, etc.) are commonly used.

However, since this resin has a large epoxy equivalent weight, the crosslinking density does not become high. For this reason, it had drawbacks such as poor curability, poor heat resistance, and poor moisture resistance. Therefore, phenol novolak type epoxy resins (e.g., Dainippon Ink & Chemicals, Epicron N-770, N-670, etc.) are used for applications that strongly require these properties, such as molding materials for encapsulating electronic components. .

In addition, tetraglycidyl ether (Yuka Ciel 3001) was also considered as a polyfunctional epoxy resin, but this project was discontinued due to lack of availability of raw materials.

The present invention is far superior to bisphenol A type epoxy resin by using an epoxy resin having bisphenol A in its novolak skeleton, which has no problems in terms of raw material supply and has an epoxy equivalent equivalent to that of phenol novolak type epoxy resin. It has been discovered that an epoxy resin composition can be obtained that has better curability, heat resistance, and moisture resistance than phenol novolak type epoxy resins.

The present invention is an epoxy resin composition comprising an epoxy resin having a novolak skeleton containing bisphenol A having the following average structural formula, a curing agent, a curing accelerator, and the like.

[Average structural formula]

The epoxy resin composition referred to in the present invention includes an epoxy resin having bisphenol A in its novolak skeleton (hereinafter referred to as bisphenol A novolak type epoxy resin), a curing agent, a curing accelerator, and usually a filler, a mold release agent, etc. Consists of surface treatment agents, etc.

Although the bisphenol A novolac type epoxy resin and other epoxy resins may be used together, it is preferable to use at least half of the bisphenol A novolac type epoxy resin in order to take advantage of the characteristics. The curing agent refers to a crosslinking agent for epoxy resins, and includes acid anhydrides, amines, phenol novolacs, and the like. The curing accelerator refers to a catalyst that causes the epoxy resin and the curing agent to react, and examples include imidazoles, tertiary amines, organic phosphine compounds, and organic aluminum compounds.

Bisphenol A skeleton novolak type epoxy resin has two epoxy groups per molecule of bisphenol A.
Since these two epoxy groups extend in opposite directions, not only is there a high probability of reaction, but three-dimensional crosslinking is always achieved. Therefore, rapid curing properties and high crosslinking density were obtained, resulting in the advantages of high thermal decomposition temperature and low water absorption, that is, excellent heat resistance and moisture resistance. In addition, the rapid curing properties enable high-cycle rationalization of molding and pressing processes, leading to cost reductions. In particular, when applied to molding materials, it has great advantages, such as eliminating the need for post-cure (also referred to as after-cure or baking) after molding.

As described above, the present invention meets the needs of society and has great industrial utility value. This will be explained below using experimental examples.

<Bisphenol A novolac type epoxy resin> 330g of bisphenol A and 65g of 37% formalin
and 1 g of sulfuric acid are reacted under reflux for 2 hours. After neutralization with barium hydroxide, the temperature was raised to 150°C to form a novolak. Thereafter, 261 g of epichloropidrine and 1.5 g of 30% sodium hydroxide were added, and a reflux reaction was carried out at 75° C. for 12 hours. After removing epichlorohydrin, 60 g of 30% sodium hydroxide was further added to carry out a cyclization reaction. Further washing and purification with water gave 340 g of a bisphenol A novolak type epoxy resin.

Comparative example 1 Bisphenol A type epoxy resin (Epicote
1001 oil-based shell epoxy) 24 parts, phenol novolac (Sumitomo Bakelite) 6 parts, crystalline silica (EC-30 Seto Ceramics Raw Materials) 70 parts, silane coupling agent (KBM-403 Shin-Etsu Chemical) 1 part, curing accelerator ( Sumikiure D (Sumitomo Chemical Industries) 0.5 part, mold release agent (Mitsuya #1 Mitsuya Wax) 1 part to 120
The mixture was kneaded for 3 minutes with heated rolls at ℃ to obtain a molding material. The Barcoll hardness (hereinafter abbreviated as Barcoll hardness) of this material was 30 when cured for 60 seconds. In addition, the glass transition point is 63℃E after molding (hereinafter referred to as Tg-A).
After -8/175 post-cure (hereinafter referred to as Tg-E), the temperature was 97°C. Further, the resin decomposition temperature (hereinafter abbreviated as decomposition temperature) determined by differential thermal analysis was 238°C. Furthermore, the moisture resistance test (hereinafter abbreviated as PCT) using a pressure cooker was conducted for 140 hours.

Comparative example 2 Orthocresol novolac type epoxy resin 20
1 part phenol novolac 10 parts The other parts were the same as in Comparative Example 1. The molding material obtained under the same kneading conditions had a barcol hardness of 60, Tg-A 116℃, Tg-E 155℃, and decomposition temperature.
The temperature was 320℃ and PCT 700hr.

Example A molding material obtained in the same manner as in Comparative Example 2 using bisphenol A novolac type epoxy as the epoxy resin had a Barcol hardness of 90, Tg-A 159°C, and Tg
-E168℃, decomposition temperature 371℃PCT 900hr.

It can be seen that compared to Comparative Examples 1 and 2, it is superior in curability, heat resistance, and moisture resistance.

Claims (1)

[Claims] 1. Bisphenol A having the following average structural formula:
An epoxy resin composition comprising an epoxy resin having a novolak skeleton, a curing agent, a filler, a curing accelerator, a mold release agent, a surface treatment agent, a flame retardant, etc. [Average structural formula]