JPS581695B2 - Thermosetting resin molding material - Google Patents

Description

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

Thermosetting resin molding materials can produce molded products with superior heat resistance and mechanical strength compared to thermoplastic resin molding materials, so molded products with such characteristics (molded products for structural materials) are required. Widely used in the field.

In order to improve the electrical performance and dimensional stability of molded articles obtained from such thermosetting resin molding materials, mica, particularly plate-shaped mica, has been added to the molding materials.

Among tabular mica, mica with a large diameter is particularly effective in improving dimensional stability.

However, mica has a layered structure with air layers between the mica layers, so when heat is applied to a molded product made of a thermosetting resin molding material containing mica, delamination occurs, causing the molded product to deteriorate. It had the disadvantage of poor heat resistance.

Such defects were particularly noticeable in tabular mica having a large diameter.

In order to eliminate such drawbacks, it is conceivable to peel off the mica in advance and use this peeled mica.

However, when the mica is peeled off in this way (mechanical peeling is performed), the mica is crushed during the peeling, so the diameter of the mica becomes smaller and the desired dimensional stability improvement effect cannot be obtained. It is.

Therefore, as a result of intensive research to eliminate the damage caused by the use of mica without impairing the effect of improving dimensional stability as described above, the inventors conducted pressure treatment on mica in advance to reduce the amount of air between the layers. It was discovered that the object could be achieved by reducing the amount and using it to produce a thermosetting resin molding material, and the present invention was completed.

In other words, the gist of the present invention is a thermosetting resin molding material containing a thermosetting resin in which the amount of air between layers is reduced by pressure treatment.

Next, this invention will be explained in detail.

Mica in which the amount of air between layers is reduced by pressure treatment may be pressurized by any method, but mica that is pressurized by the following method is preferable from the viewpoint of effectiveness.

(1) Pressure between two rotating rolls When pressurizing in this way, it is possible to pass only mica between the rotating rolls (dry method), or to pass water, toluene, methanol, acetone, etc. It may be possible to pass the mica together with a solvent (wet type) to minimize the pulverization of the mica.

Moreover, the combined use of adhesive substances such as resol and polyester is particularly effective in preventing mica from slipping between rolls.

(2) Pressure by pressing It is preferable to perform pressure treatment by pressing at a pressure of 1 kg/mm 2 or more.

As the thermosetting resin, commonly used phenol resins, urea resins, melamine resins, furan resins, epoxy resins, and polyester resins are used alone or in combination.

The thermosetting resin molding material of the present invention is produced in a conventional manner using the above-mentioned thermosetting resin, the above-mentioned mica, and other additives if necessary.

In this case, the amount of pressure-treated mica to be used may be selected so that the pressure-treated mica is contained in the thermosetting resin molding material in an amount of 5 to 70% by weight (hereinafter abbreviated as "%"). preferable.

That is, if the content of pressure-treated mica is below the above range, the effect of improving dimensional stability will be small, and if it is above the content, it will tend to become unsuitable as a molding material.

Moreover, it is preferable that the particle size of the Myroku is 8 to 400 mesh.

Those having a particle size exceeding 8 mesh are preferably pulverized so that the particle size falls within the above range.

Furthermore, particles with a small particle size of 400 mesh or less are poor in improving dimensional stability.

As described above, the thermosetting resin molding material of the present invention has high heat resistance and dimensional stability because it contains mica whose interlayer air content is reduced by pressure treatment. This makes it possible to produce molded products with excellent electrical properties and other properties.

In particular, mica that is flat and has a large diameter can produce molded products with even greater dimensional stability.

Next, examples will also be described as comparative examples.

Example 1 Formalin, (formaltehyde)/
(Uria) was blended so that the molar ratio was 1.5, and the pH was adjusted to 7.5 using ammonia.
A resin syrup was obtained by reacting at ℃ for 3 hours.

Next, for 100 parts by weight of this syrup, add 1 part by weight of pulp.
0 parts by weight and a curing accelerator were added, and further 20 parts by weight of 20 mesh pressure-treated mica (Nuzorite Mica 20S, manufactured by Kuraray Co., Ltd.) were added and kneaded.

The pressure-treated mica is pre-wetted with methanol, and then placed on a mixing roll with both rolls rotating at the same speed.
It was subjected to pressure treatment 0 to 15 times.

Next, this kneaded product was dried at 80° C. until the moisture content became 5%.

Next, 0.2 parts by weight of zinc stearate was added to 100 parts by weight of this material and the mixture was ground to obtain a molding material.

Example 2 Formalin (formaldehyde) for melamine
The mixture was blended so that the molar ratio of /(melamine) was 2.5, the pH was adjusted to 9.0 using sodium carbonate, and the mixture was reacted at 80° C. for 2 hours to obtain a resin syrup.

Next, 1 part of pulp was added to 100 parts by weight of this syrup.
0 parts by weight and a hardening accelerator were added, and further 30 parts by weight of 20 mesh pressure-treated mica were added and kneaded.

Next, this kneaded product was dried at 80° C. until the moisture content became 5%.

Next, 0.2 parts by weight of zinc stearate was added to 100 parts by weight of this material, and the mixture was ground to obtain a molding material.

Example 3 A polyester resin was prepared by condensing polypropylene glycol, maleic anhydride, and isophthalic acid, and the polyester resin and other raw materials were blended as follows.

At this time, the pressure-treated mica was compressed at a pressure of 100 kg/mm2 for 15 minutes.

Polyester resin・・・・・・・・・・・・・・・・・・
...25 parts by weight glass fiber...
・・・・・・・・・・・・・・・・・・15 〃20
Mesh pressure treated mica...50 Diaryl phthalate resin...10 t-
Butyl perbenzoate...1 Zinc stearate...2
Next, the above compound was kneaded using a heated roll to obtain a molding material.

Example 4 Each raw material was mixed as follows.

Pressure-treated mica is dry-pressure-treated 10 to 15 times with mixing rolls kept at the same rotational speed.

Epoxy resin···················
・・・・・・30 parts by weight Glass fiber・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・10
〃20 mesh pressure treated mica...40
Diaminodiphenylmethane・・・・・・・・・10
silica······················
・・・・・・・・・・・・・・・・・・10 〃Zinc stearate・・・・・・・・・・・・・・・・・・・・・ 1
Next, the above compound was kneaded using a heated roll to obtain a molding material.

Example 5 Each raw material was mixed as follows.

The phenol resin is obtained by reacting phenol and formaldehyde in a conventional manner under an acid catalyst, and has a softening point of 90° C. and a number average molecular weight of 500.

Further, the pressure-treated mica is obtained by pressure-treating the mica together with the resol resin obtained in a conventional manner 10 to 15 times using a mixing roll at the same rotation speed.

In this case, the weight ratio of (resol)/(mica) is 0.05
Pressure treatment was performed with the setting set to

Phenol resin・・・・・・・・・・・・・・・
・・・・・・40 parts by weight of xamine・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・ 6 〃
20 mesh pressure treated mica...50 Magnesium stearate...1 Calcium hydroxide...
...3 Next, the above compound was kneaded and ground using a heating roll to obtain a molding material.

Comparative Examples 1 to 5 Molding materials were obtained in the same manner as in Examples 1 to 5, respectively, except that untreated mica was used.

Comparative Example 6 A molding material was obtained in the same manner as in Example 5, except that the pulverizing material having a particle size of 400 mesh or less was used without treatment.

A molded article was made using the molding material obtained as described above, and its heat resistance temperature and molding shrinkage rate were determined.

The results are shown in the table below. As is clear from the table, it can be seen that the molded articles obtained from the molding materials of Examples have better heat resistance than the molded articles obtained from the corresponding molding materials of Comparative Examples.

Moreover, as is clear from the comparison between Example 5 and Comparative Example 5, it can be seen that the molded article obtained from the molding material of Example 5 has excellent dimensional stability.

Furthermore, as is clear from the comparison between Example 5 and Comparative Examples 5 and 6, it can be seen that when mica having a small particle size is used, the dimensional stability of the obtained molded product is significantly deteriorated.

Claims (1)

[Claims] 1. A thermosetting resin molding material containing mica in which the amount of air between layers is reduced by pressure treatment. 2. The thermosetting resin molding material according to claim 1, wherein the mica is a flat mica. 3. The thermosetting resin molding material according to claim 1 or 2, wherein the mica has a particle size of 8 to 400 mesh. 4. The thermosetting resin molding material according to any one of claims 1 to 3, wherein the mica is contained in an amount of 5 to 70% by weight.