JPS5827098B2 - Manufacturing method for molded products including inserts - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a molded article including an insert.

SMC (sheet molding compound) and BMC (bulk molding compound) are used as molding materials in the molding method that uses a mold consisting of an upper mold and a lower mold to obtain a molded product in a closed environment. It used to be necessary to consider how the SMC and BMC would flow throughout the mold, but as mold forming technology has progressed, it has become easier to create small gaps within the mold. Its use has expanded to include molded products in which parts (inserts) are placed and the inserts are encapsulated with molding material.

In order to obtain molded articles containing such inserts, SM
If C or BMC is used, molding is easy and a satisfactory molded product can be obtained.

However, it has the disadvantage that the molding material does not impregnate into the minute gaps.

In order to improve the viscosity of conventional molding materials, methods to improve these problems include increasing the amount of cross-linking agent, lowering the molecular weight of the resin, and prolonging the gelling time, thereby molding into fine gaps. The material has been impregnated.

In these methods, a large amount of molding material flows out from the gap between the upper mold and the lower mold, contaminates the mold, requires a long time to clean the mold, and is not suitable for productivity.

In addition, since the molding material comes out from inside the mold, it can cause fatal defects in the molded product, such as cavities and weld lines, which can significantly reduce the strength of some parts of the molded product. I couldn't come up with something that would hold up as a product.

The present invention has been developed in view of these points, and the intended purpose is that when a molded product is obtained by encapsulating an insert having a gap of 0.1 μ to 1 m TIL with a molding material, the molding material is not exposed to the outside of the mold. without flowing out, and at 0.1
It is an object of the present invention to provide a method for manufacturing a molded article by impregnating a molding material even into a gap between 1 μm and 1 μm.

The present invention involves reacting an unsaturated epoxy ester resin obtained by reacting a polyepoxide with an approximately equivalent amount of αβ unsaturated basic acid with 2 to 10 mol% of maleic anhydride based on the hydroxyl groups of the unsaturated epoxy ester resin. A thermosetting resin composition containing the resin obtained by
The present invention relates to a method for manufacturing a molded article containing an insert, which is characterized by introducing the insert around the insert having a gap of 1 μm to 1 μm and curing the insert.

According to the manufacturing method of the present invention, 17n7IL~0.1μ
The insert having a gap of m is also impregnated with the molding material, and a molded product can be obtained without the molding material flowing out into the gap between the upper and lower molds of the mold.

The resin used in the present invention is produced by adding polyepoxide and approximately the same amount of αβ unsaturated basic acid at 80°C to 120°C in the presence of an addition catalyst and a polymerization inhibitor, and upon completion of the addition reaction. It is obtained by adding 2 to 10 mol% of maleic anhydride to the hydroxyl group of an unsaturated epoxy ester resin.

The reaction formula is It is indicated by.

In the above formula, R7-R6 are hydrogen or an alkyl group.

The reason for limiting maleic anhydride to 2 to 10 mol% is 2.
If it is less than mol%, the characteristics of the present invention cannot be fully exhibited, and if it exceeds 10 mol%, gelation tends to occur during the reaction between the unsaturated epoxy ester resin and maleic anhydride.

The polyepoxide used in the present invention has, per molecule,
Containing one or more epoxy groups, such as glycidyl polyethers of polyhydric alcohols or polyhydric phenols, epoxidized fatty acids or drying oil acids, epoxidized diolefins, esters of epoxidized cine-saturated acids, epoxidized unsaturated polyesters, etc. is used.

Examples of αβ-unsaturated basic acids include methacrylic acid, acrylic acid, and crotonic acid.

A part of the αβ-unsaturated basic acid may be replaced with a saturated polybasic acid.

Examples of saturated polybasic acids include phthalic anhydride, tetrahydrophthalic anhydride, and pyromellitic anhydride.

As addition catalysts, metal halides such as zinc chloride and lithium chloride, sulfides such as dimethyl sulfide and methylphenyl sulfide, sulfoxides such as dimethyl sulfoxide and methyl ethyl sulfoxide,
NN Tertiary amines such as dimethylaniline, pyridine, triethylamine and their hydrochlorides or bromates, quaternary ammonium salts such as tetramethylammonium chloride and trimethyldotecylbenzyl ammonium chlorite, sulfonic acids such as para-toluenesulfonic acid, Examples include mercaptans such as ethyl mercaptan and propyl mercaptan.

Examples of polymerization inhibitors include hydroquinone, tert-butylcatechol, p-benzoquinone, and 2.5 di-tert-butylhydroquinone.

A resin obtained by reacting an unsaturated epoxy ester resin with maleic anhydride may be dissolved in an αβ-ethylenically unsaturated monomer.

The αβ-ethylenically unsaturated monomers that dissolve this resin include styrene, vinyltoluene, ethylvinylbenzene, isopropylstyrene, tert-butylstyrene, α-methylstyrene, n-butylstyrene, divinylbenzene, and halogenated monomers. Examples include styrene, diallyl tucrate, triallyl cyanurate, acrylic acid, vinyl acetate, acrylic esters (methyl acrylate, ethyl acrylate, etc.), methacrylic esters (methyl methacrylate, ethyl methacrylate, etc.).

The resin is mixed in an amount of 30 to 90% by weight, and the αβ-ethylenically unsaturated monomer is mixed in a range of 70 to 10% by weight.

In the present invention, this resin alone or a resin solution may be used, but other materials may also be mixed.

Other materials include calcium carbonate, mica, alumina,
These include fillers such as zirconia, chalk, silicic acid, slate, barium oxide, and magnesium oxide, and reinforcing materials such as glass fiber, carbon fiber, organic fiber, asbestos, and paper.

As curing agents for curing these molding compositions, benzoyl peroxide, lauryl peroxide, methyl ethyl ketone peroxide, tert-butyl perbenzoate, etc. are used.

The insert having a gap of 1 mm to 0.1 μ in the present invention includes a wound enameled wire, a stacked core, a plurality of bobbins, etc., and a gap of 1 mm to 0.1 μ between them.
There are transformer motors, solenoid coils, flyback transformers, etc. that have a gap of 1 μm.

The above resin composition is introduced around these in the mold and cured to form a molded product.

This is done by trancore molding, injection molding, etc.

The molded product containing the insert obtained by the manufacturing method of the present invention has excellent electrical properties and strength because the molding material enters the gap of 0.1 μm to 111 Lm in the insert, and the molding material does not come out of the mold during molding. It is also a molded product with improved performance.

The present invention will be described in detail.

Parts are by weight.

Example 1 ■-1 Production of resin composition in the present invention Epoxy resin Ep828 (epoxy equivalent: 188) manufactured by Shell Chemical, USA. 0 parts of O, 45.8 parts of meccrylic acid, 0.5 parts of benzyldimethylamine, 0.0 parts of hydroquinone.
01 part was charged, heated on an oil bath at 105°C, and reacted for 6 hours (acid value 2).

Then, at the same temperature, add 2.7 parts of maleic anhydride and
Allowed time to react.

The acid value of the reaction product was 15.

A resin composition A was obtained by adding 30 parts of styrene to 100 parts of this resin.

The viscosity of resin composition A was 8 poise at 25°C.

■-2 Manufacture of resin composition used in comparative example Epoxy resin Ep828 manufactured by Shell Chemical Co., Ltd. (epoxy equivalent: 1
88) 100 parts, 45.8 parts of methacrylic acid, 0.5 parts of benzyldimethylamine, and 0.01 part of hydroquinone were charged, heated on an oil bath at 105°C, and reacted for 6 hours (
Acid value 2).

3 parts of styrene to 100 parts of this unsaturated epoxy ester resin
0 parts were added to obtain resin composition B.

The viscosity of resin composition B was 4 poise at 25°C.

1-3 Evaluation of resin composition The formulation of the molding material used for evaluation of the resin composition was resin composition/benzoyl peroxide/calcium carbonate (weight ratio).
Takehara Chemical 5L-300)/+inch glass fiber-10
It is 0/1.0/100/30.

These materials were kneaded using a kneader. Table 1 shows the properties and molding results of the kneaded product.

As shown in the results in Table 1, the molding material using the resin composition A of the present invention did not generate any flakes and was sufficiently impregnated into the insert part having a gap of 0.01.

However, in the conventional resin composition B, 0.011ftrIL
However, on the other hand, there was a lot of burr formation, and it took an abnormal amount of time to remove the burr, resulting in poor workability.Also, with the generation of burr, no pressure was applied to the molded product, so there was a lot of burr in the molded product. occurred frequently.

Example 2 2-1 Production of resin composition in the present invention 30 parts of epoxy resin Ep828 manufactured by Shell Chemical (epoxy equivalent: 188), 70 parts of EplOOl (epoxy equivalent: 490), 26 parts of methacrylic acid, 0.5 part of benzyldimethylamine, 0.01 part of hydroquinone was charged, heated on a 120°C oil bath, and reacted for 5 hours (acid value 3).

Then, at the same temperature, add 2.94 parts of maleic anhydride and
Allowed time to react.

The acid value of the reaction product was 15. Resin composition C was obtained by adding 30 parts of styrene to 70 parts of this resin.

The viscosity of resin composition C was 60 poise at 25°C.

2-2 Production of resin composition used in comparative example Epoxy ester resin Ep828 manufactured by Shell Chemical Co., Ltd. (epoxy equivalent: 188
) 30 parts, Eplool (epoxy equivalent: 490) 70 parts, methacrylic acid 26 parts, benzyldimethylamine 0.5
1 part and 0.01 part of hydroquinone were heated on an oil bath at 120°C and reacted for 5 hours (acid value 3).

70 parts of this unsaturated epoxy ester resin and 30 parts of styrene
A resin composition was obtained.

The viscosity of the resin composition was 50 poise at 25°C.

2-3 Evaluation of resin composition Various molding materials were created and evaluated.

The results are shown in Table 2.

From the results in Table 2, the molding material using the resin composition C of the present invention does not generate flakes and is sufficiently impregnated into the insert portion having a gap of 0.01 mm.

However, with conventional resin compositions, impregnation into gaps as small as 0.01 mm is poor, and a lot of debris occurs, and it takes time to salt the debris, resulting in poor workability.In order to improve productivity** , injection molding was used, but its advantages could not be utilized.

Example 3 Using the resin compositions C and D used in Example 2, the viscosity and moldability of the mixture were investigated.

The results are shown in Table 3.

From the results in Table 3, even if the molding material using the resin composition C of the present invention has a high viscosity, the resin is impregnated into a gap of 0.01 mm.

On the other hand, conventional resin compositions can fit into a gap of 0.01 mm if the viscosity of the molding material is lowered, but they often generate flakes and have poor workability.

Claims (1)

[Claims] 1. An unsaturated epoxy ester resin obtained by reacting a polyepoxide with an approximately equivalent amount of αβ-unsaturated basic acid has 2
A thermosetting resin composition containing a resin obtained by reacting ~10 mol% of maleic anhydride is heated to 0.1μ in a mold.
introduced around the insert having a gap between m and 1;
A method for producing a molded article including an insert, which is characterized by being cured.