JPH11199752A - Production of phenolic resin molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a phenolic resin molding material which can give a product improved in heat resistance, electrical insulation properties, and mechanical strengths by mixing and milling glass fibers produced in a process for raising the surface of a glass cloth with a phenolic resin. SOLUTION: The surface of a glass cloth is raised to yield glass fibers having a length of 150 μm or below as a by-product. The glass fibers are mixed with a novolac or resol phenolic resin, a curing agent and/or a curing catalyst such as of an ammonia type such as hexamethylenetetramine or of an oxygen type, a mold release, and a filler such as a wood flour by means of a blender, the obtained mixture is milled with rolls under heating, the product is ground, and the fine powder is removed by classification to obtain a phenolic resin molding material. Thus, it is possible to recycle into useful resources a glass powder which has heretofore been disposed of and is capable of being easily dispersed and milled by means of a common production equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenolic resin molding material having excellent mechanical strength in addition to heat resistance and electrical insulation properties.

[0002]

2. Description of the Related Art Phenol resins have been used for electric parts such as various relays and automobile parts because they have heat resistance and excellent mechanical strength in addition to electric insulation properties. As the uses of molded articles have expanded, many fillers, such as wood powders, mixed and kneaded with phenolic resins have come to be used according to the use of molded articles and required characteristics. In applications where heat resistance and mechanical strength are particularly required, short glass fibers are often used. However, these short glass fibers are considerably more expensive than wood flour and the like. BACKGROUND ART A glass cloth in which glass fibers are woven in a cloth shape is used in large quantities, for example, as a main material of a circuit board. In recent years, a method of raising the surface of the glass cloth in order to coat the glass cloth surface with a sufficient amount of resin may be used. Glass powder is generated at the time of this raising process, and the glass powder is collected and collected by a dust collector and is treated as waste.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a phenolic resin molding material which can form a molded article having excellent heat resistance and mechanical strength using an inexpensive filler.

[0004]

According to the present invention, there is provided a phenol resin characterized in that short fiber glass fibers (hereinafter referred to as glass powder) generated in a step of raising the surface of a glass cloth are mixed and kneaded with the phenol resin. The present invention relates to a method for producing a molding material. Phenolic resin molding materials
Generally, a phenolic resin is mixed with a curing agent and / or a curing catalyst and a filler such as wood flour, etc., well by a blender or the like, kneaded with a roll or the like, and then subjected to processes such as pulverization and classification. As the phenol resin, a novolak type or a resol type is used. As a curing agent and / or a curing catalyst, an ammonia-based one such as hexamethylenetetramine is used for the novolak type, and an acid-based one is used for the resole type. Generally, wood flour is often used as a filler.

In the case where heat resistance and mechanical strength are required for electric parts and automobile parts, use of short glass fibers has recently increased, but short glass fibers are more expensive than wood flour. . Short glass fibers, such as chopped strands, having a short fiber length of about 1.5 mm are often used. It is becoming. In addition, since the appearance of the molded product is better when it is 150 μm or less, the length of the glass fiber as the raw material is often adjusted to be 150 μm or less. According to the method of the present invention, glass powder generated in the step of raising the surface of the glass cloth is used, so that it can be obtained inexpensively as a raw material, and since the ratio of powder having a size of 150 μm or less is large, it is mixed and kneaded with a phenol resin. In this case, the dispersion in the resin is easy, and the appearance of the obtained molded product is also good. Therefore, this glass powder can be used in the same amount and in the same manner as the conventionally used glass chop strand. Further, a part of the glass chop strand can be replaced with this glass powder, and it is naturally possible to use it together with another filler.

[0006] In order to knead the above-mentioned glass powder with a phenol resin as a filler, it is possible to use ordinary production equipment for a phenol resin molding material. For example, in the case of a novolak type, this glass powder is added to a powdered phenolic resin together with hexamethylenetetramine, a release agent and other additives, mixed with a blender, heated and kneaded with a roll, and then pulverized to classify the fine powder. Removed to form molding material. As described above, since this glass powder contains a large amount of fine powder of 150 μm or less, it can be easily dispersed and kneaded with ordinary production equipment. According to the present invention, by using glass powder discarded as fine powder as a filler, a phenol resin molding material having excellent heat resistance and mechanical strength can be produced at low cost.

[0007]

EXAMPLE As shown in Table 1 below, a molding material of Formula A using chopped strands made of short fiber glass fibers as a filler, and the entire amount of the chop strands were collected from a dust collector of a brushing apparatus for a glass cloth surface. A molding material of Formulation B, which was replaced with the glass powder taken out, was produced by a conventional method. Using the obtained powdery molding material, a molded product (test piece) was injection molded. The appearance and mechanical strength characteristics of the molded articles were measured and compared. The molding materials of both formulations had good appearance and little difference in characteristic values.

[0008]

[Table 1]

[0009]

According to the method of the present invention, the glass powder generated during the process of raising the surface of the glass cloth is conventionally treated as waste, but according to the method of the present invention, it is effectively used as a filler for the phenolic resin molding material. Not only can a molding material that can be used and can be used to form a molded article having excellent heat resistance and mechanical strength be produced at low cost, but this glass powder can be recycled and used as a useful resource.

Claims (1)

[Claims] 1. A method for producing a phenolic resin molding material, comprising mixing and kneading short glass fibers produced in a step of raising the surface of a glass cloth with a phenolic resin.