JPS6021661B2 - Thermosetting resin molding material - Google Patents

Description

[Detailed description of the invention] This invention relates to a thermosetting resin molding material.

In general, thermosetting resin molding materials are used as structural materials in various fields because they can produce molded products with superior heat resistance and mechanical strength compared to thermoplastic resin molding materials. When thermosetting resin molding materials are used for such purposes, various fillers are generally added to the molding material in addition to the thermosetting resin, thereby improving the moldability of the molding material. In addition to improving
We aim to improve the mechanical, physical, and electrical performance of molded products. Among these fillers, tabular mica is the most excellent in improving the electrical performance and dimensional stability of molded products. In particular, among the tabular mica, the larger the aspect ratio (diameter/thickness), the better the effect. However, flat mica has a larger elastic modulus than resin and is more rigid, so it has poor compatibility with resin. Therefore, when tabular mica is blended into a molding material, the resin and tabular mica separate, resulting in poor handling and moldability of the molding material, resulting in the inability to produce molded products with good surface conditions. was. In order to solve this problem, it has been considered to treat the flat mica with an appropriate surface treatment agent to improve its compatibility with the resin. However, since tabular mica is a layered crystal material, even if only its surface is treated, delamination occurs internally, and the effectiveness of the treatment is not improved. Therefore, thermosetting resin molding materials containing tabular mica still have poor handling and moldability, and molded products obtained using them have the disadvantage of poor surface conditions. Therefore, the inventors continued a series of studies in order to eliminate the drawbacks of thermosetting resin molding materials containing such flat mica, and as a result, they developed a combination of flat mica and fibrous filler. It has been found that the above-mentioned drawbacks can be overcome. In this case, among the fibrous fillers, the use of asbestos produced the most excellent effects.
Asbestos has excellent heat resistance, and is also excellent in terms of price, moldability, and mechanical performance. However, the use of asbestos is strictly regulated because it deteriorates the working environment and occupational health conditions and causes pollution problems. Furthermore, since asbestos does not have good electrical performance, it has the disadvantage that the electrical performance of molded products made from molding materials containing it is somewhat poor. The inventors have proposed a fibrous filler that can replace such asbestos,
As a result of further research to find something with better electrical performance than asbestos, they discovered that fibrillated fibrous polyethylene was extremely effective and completed this invention. . That is, the present invention provides a thermosetting resin molding material containing flat mica having a particle size of 60 mesh or more, which is characterized in that it also contains fibrillated synthetic fiber aggregate polyethylene. This is the summary.

Next, this invention will be explained in detail.

In this invention, fibrillated synthetic paper-like polyethylene is used in combination with tabular mica.

Preferably, the fibrillated synthetic polyethylene is highly fibrillated and has a high density. Non-fibrillated materials have poor dispersibility and deteriorate the mechanical performance and heat resistance of molded products. An example of the fibrillated fibrous polyethylene is "Chemivest" manufactured by Mitsui Zeravac. As the tabular mica, one having a particle size of 60 mesh or more is used. If it is smaller than this, dimensional stability will be lacking. However, among particles having such a particle size, it is preferable to use particles having a large aspect ratio. The amount of fibrillated fibrous polyethylene used is preferably selected so that the fibrillated synthetic polyethylene is contained in the thermosetting resin molding material in an amount of 0.5 to 25% by weight.

Namely. In order to improve the electrical performance of molded products,
Although it is preferable to increase the amount of fipril synthetic fiber general polyethylene used, if the amount used is too large, the heat resistance of the molded product will decrease. Therefore, taking these into consideration, it is preferable to set the upper limit of the amount of fibrillated synthetic polyethylene used as described above. Note that if the amount of fibrillated synthetic polyethylene used is less than the above range, the effect tends to decrease by 4. The thermosetting resin molding material of the present invention is produced in the same manner as usual. That is, it is produced by thoroughly mixing fibrillated polyethylene, plate-shaped mica, resin, curing agent, etc., and then kneading with a roll or kneader. The thermosetting resin molding material 0 produced in this way contains fibrillated synthetic fiber polyethylene and tabular mica, and is therefore easy to handle. That is, since the bulk density of the molding material is high and the resin and the plate-like mica do not separate when the molding material is crushed, the amount of fine powder generated is extremely small. Moreover, moldability is also good. That is, it has excellent filling properties during molding and bush-like properties of the molded product. Furthermore, the surface condition and dimensional stability of the molded product obtained are also excellent. In particular, the molding material of the present invention contains flat mica and fibrillated fibrous polyethylene, so unlike molding materials that use a combination of flat mica and asbestos, it has extremely high electrical performance at room and high temperatures. It is possible to produce excellent molded products. In addition, as the thermosetting resin, phenol resin, polyester resin, gialphthalate resin,
Particularly effective is the use of epoxy resin. Next, examples will be described together with comparative examples.

[Example 1] As a thermosetting resin, a softening point of 90 was obtained by reacting ordinary fer/- and formaldehyde under an acid catalyst.
A phenolic resin having a number average molecular weight of 500 was used, and other raw materials were blended with it as shown below.

Phenol resin...4 parts by weight Hexamine...6 Tabular mica (6
0 mesh or more)...43 Chemivest (manufactured by Mitsui Zeravac Co., Ltd.)...10 Magnesium stearate...1 Next, after thoroughly mixing this mixture, knead it using a heating roll. It was made into a molding material, and then crushed to a particle size of 7 ribs or less using a crusher to obtain a pulverized molding material.

[Example 2] The composition of each raw material was changed as follows.

A pulverized molding material was obtained in the same manner as in Example 1 except for the above.
Phenol resin...4 parts by weight Hexamine...6 Tabular mica (60
mesh or higher)...48 Chemivest (manufactured by Mitsui Zeravac)...5 parts by weight magnesium stearate
...1 [Example 3] The composition of each raw material was changed as follows.

A pulverized molding material was obtained in the same manner as in Example 1 except for the above.
Phenol resin...4 parts by weight Hexamine...6 Tabular mica (6
0 mesh or more)...28 Chemivest (manufactured by Mitsui Zeravac)...25 Magnesium stearate...1 [Example 4] Polypropylene glycol, maleic anhydride and isophthalic acid as thermosetting resins A polyester resin obtained by condensation and a diallyl phthalate resin obtained in a conventional manner were used, and other raw materials were blended therewith as described below.

Polyester resin...25 parts by weight Diaryl phthalate resin...10 t-butyl/
Gubenzoate...1 〃Tabular mica (60 mesh or more)...48 〃Chemivest (manufactured by Mitsui Zeravac)...15 parts by weight magnesium stearate
1. Then, the subsequent steps were carried out in the same manner as in Example 1 to obtain a pulverized molding material.

[Example 5] As the thermosetting resin, a conventionally obtained/volatile type epoxy resin was used, and other raw materials were blended with it as described below.

Epoxy resin...3 parts by weight Diaminodiphenylmethane...10 Flat mica (60 mesh or more)...44 Chemivest (manufactured by Mitsui Zeravac)...15 Magnesium stearate 1 And this The subsequent steps were carried out in the same manner as in Example 1 to obtain a pulverized molding material.

[Comparative example 1] Flat mica was used instead of Chemibet.

A pulverized molding material was obtained in the same manner as in Example 1 except for the above.
The raw material composition is as follows. phenolic resin
...4 parts by weight of xamine
...6〃Tabular mica (60 mesh or more)...53〃Magnesium stearate
...1 [Comparative Example 2] Flat mica was used instead of Chemivest.

A pulverized molding material was obtained in the same manner as in Example 4 except for the above.
[Comparative Example 3] Flat mica was used instead of Chemivest.

A pulverized molding material was obtained in the same manner as in Example 5 except for the above.
Conditions of the pulverized molding materials obtained in the above Examples and Comparative Examples, high density and surface conditions of molded products manufactured using the same, dimensional stability (molding shrinkage rate), heat distortion temperature, electrical performance (insulation resistance) ) was measured. The results are shown in the table below. As is clear from the table, the molding material (pulverized) of the example has good compatibility with the flat mica and resin, high density, good surface condition, dimensional stability, heat resistance, and electrical performance. It can be seen that excellent molded products can be manufactured.

Claims (1)

[Claims] 1. A thermosetting resin molding material containing tabular mica having a particle size of 60 mesh or more, characterized in that it also contains fibrillated fibrous polyethylene.