JPH07278422A - Unsaturate polyester resin molding material - Google Patents

Abstract

PURPOSE:To obtain the subject material having high heat resistance. CONSTITUTION:This molding material is the one comprising 15-35 pts.wt., in total, unsaturated polyester resin containing terephthalic acid as the saturated acid of a resin material and having n acid value of 20-40mg/KOH, a crosslinking agent and a reaction initiator and 65-85 pts.wt. inorganic base material, wherein the inorganic base material used comprises comprises at least one compound having no water of crystallization or a liberation temperature of crystallization water of 400 deg.C or above and being desirably a glass fiber, silica, clay, calcium carbonate, magnesium oxide, mica or antimony trioxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an unsaturated polyester resin molding material which has little change in appearance and deterioration in strength at high temperatures.

[0002]

2. Description of the Related Art Unsaturated polyester is a phenolic resin,
Compared to epoxy resin, diallyl phthalate resin, etc., it has a high balance of electrical properties such as dielectric breakdown strength, insulation resistance, tracking resistance, arc resistance, etc., so it is suitable for insulating parts such as heavy electrical equipment and automobile electrical components. It has been widely used. However, there are high heat resistant resins such as resole type resins for phenolic resins and diallyl isophthalate resins using isophthalic acid as a raw material for diallyl phthalate resins. Even epoxy resins have excellent heat resistance as a curing agent. There are grades with improved heat resistance, such as using resin and incorporating a rigid group in the skeleton. For this reason, unsaturated polyester resins have often yielded to other resins in spite of having excellent electrical properties for parts that require high heat resistance.

Particularly, recently, application of a thermosetting molding material has been studied because it is advantageous in terms of cost for surface mounting chip parts that require soldering heat resistance at 400 ° C. such as liquid crystal resins. Therefore, the development of high heat resistant grades for each resin is one of the important themes. Unsaturated polyester resin originally has lower crosslink density and lower heat resistance than other resins, and since aluminum hydroxide is mainly used as a flame-retardant base material for molded products, it is decomposed at 220 ° C or higher. Also, due to the influence of water of crystallization, shell cracks are generated on the surface of the molded product, and the strength is reduced to about 15% of room temperature.

[0004]

In recent years, as the performance of products has improved, the demand for materials having even higher electrical performance in high heat-resistant parts has increased, and unsaturated polyester resin molding materials have been reviewed. TECHNICAL FIELD The present invention relates to an unsaturated polyester resin molding material having extremely small changes in appearance and deterioration in strength at high temperatures.

[0005]

According to the present invention, an acid value using terephthalic acid as a saturated acid of a resin raw material is 20 to 40 mg.
/ KOH unsaturated polyester resin, cross-linking agent and reaction initiator in total 15 to 35 parts by weight, and inorganic base material 65 to 85
It is composed of parts by weight and does not have crystal water such as glass fiber, silica, clay, calcium carbonate, magnesium oxide, mica, and antimony trioxide as an inorganic base material, or when the decomposition occurrence temperature of crystal water is 400 ° C or more. It is intended to provide an unsaturated polyester resin molding material characterized by using one kind or two or more kinds of a certain compound, which has extremely little deterioration in appearance after heat treatment and strength deterioration under heat.

The unsaturated polyester resin used here is a resin having a terephthalic acid skeleton in which terephthalic acid is used as a saturated acid as a resin raw material, and an acid value of 20 to 40 mg / KOH is used. An isophthalic acid-based unsaturated polyester resin or an unsaturated polyester resin having an acid value of 20 mg / KOH or less is not suitable for the purpose of the present invention because the cured product has a small crosslink density and thus has insufficient heat resistance.

Examples of the cross-linking agent include vinyl monomers such as styrene, diallyl phthalate (DAP), methacrylic acid methyl ester, divinylbenzene, acrylamide, vinyltoluene, monochlorostyrene and acrylonitrile, and diallyl phthalate prepolymers. What is used. Examples of the reaction initiator include benzoyl peroxide, lauroyl peroxide, butyl peroxybutane, di-t-butyl peroxyisophthalate, dicumyl peroxide (DC
P), 2,5-dimethylhexane-2,5-dihydroperoxide, t-butylperoxybenzoate,
A peroxide such as methyl ethyl ketone peroxide is used.

Regarding the inorganic base material to be used, if it has crystal water, it may precipitate due to decomposition at high temperature, which may adversely affect the appearance and strength of the molded product. The decomposition temperature must be 400 ° C or higher. This is because 400 ° C. is a soldering temperature when it is used for surface mounting parts and the like, and is considered to be the maximum operating temperature of the thermosetting resin. Therefore, aluminum hydroxide, magnesium hydroxide, zinc borate, etc. cannot be used. The compounds that can be used are limited to compounds such as glass fiber, silica, clay, calcium carbonate, magnesium oxide, mica and antimony oxide. Each compound can be used alone or in combination.

[0009]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. Tables 1 and 2 show the composition of the molding material. The composition having such a composition was kneaded with a hot roll at 90 ° C., formed into a sheet, cooled, and pulverized into a molding material.

[0010]

[Table 1]

[0011]

[Table 2]

A test piece obtained by transfer molding at 165 ° C. for 4 minutes was measured for deflection temperature under load, flexural strength under heat, appearance after heating, and deterioration of appearance during immersion in solder. The results are shown in Table 3.

[0013]

[Table 3]

[0014]

As is clear from the above Examples and Comparative Examples, the unsaturated polyester resin molding material of the present invention has a high degree of heat resistance. It is suitable for high heat resistant parts where polyester resin could not be used.

Claims (2)

[Claims] 1. A total of 15 to 35 parts by weight of an unsaturated polyester resin having an acid value of 20 to 40 mg / KOH using terephthalic acid as a saturated acid of a resin raw material, a crosslinking agent and a reaction initiator, and an inorganic base material 65. To 85 parts by weight, and one or more compounds having no water of crystallization or having a decomposition temperature of water of crystallization of 400 ° C. or more as an inorganic base material are used. Molding material. 2. The inorganic substrate is glass fiber, silica, clay, calcium carbonate, magnesium oxide, mica, 3
The unsaturated polyester resin molding material according to claim 1, which is antimony oxide.