JPH107885A - Phenolic resin forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phenolic resin forming material, excellent in moisture resistance, heat resistance and electric characteristics, all of which are essential in small-sized, thin electronic parts, etc., improved in brightness which is a weak point of a thermosetting resin forming material, and having excellent flexibility. SOLUTION: This forming material contains a novolac-type phenolic resin as the main component of resin, and an organic fibrous material and an acrylonitrile butadiene rubber as fillers. The organic fibrous material as a filler consists of crushed cloth, etc., and the material is compounded in an amount of 8-25 pts.wt. based on 100 pts.wt. of the resin component. Further, the acrylonitrile butadiene rubber as another filler is a partially crosslinked-type or a carboxy- modified-type rubber, and it contains bonded acrylonitrile in an amount of 30-45% and has a compatibility parameter of 9-11. The acrylonitrile butadiene rubber is compounded in an amount of 5-25wt.% based on 100 pts.wt. of the resin component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a phenolic resin molding material having excellent flexibility, and more particularly to a phenolic resin molding material suitable for a part having a fitting shape.

[0002]

2. Description of the Related Art Phenolic resins are excellent in heat resistance, strength, moldability, etc. among various thermosetting resins.
It is used for various purposes such as molding materials and laminates. Among them, phenolic resin molding materials have been used in many electronic parts in recent years, and such parts are required to have characteristics such as moisture resistance, dimensional stability, heat resistance, and electrical insulation. In particular, in recent years, electronic components have been reduced in size and thickness, and flexibility has been demanded in order to prevent cracking or chipping during finishing or transportation, or as the number of fitting components increases due to integration of components. In general, a thermosetting resin molding material containing a phenolic resin molding material has a disadvantage that it is hard and brittle because of a three-dimensional structure as compared with a thermoplastic resin molding material. In order to improve this point, various fillers and elastomers have been studied. However, phenolic resins which are satisfactory such as problems such as reduced moisture resistance and heat resistance and insufficient flexibility cannot be obtained. No molding material has yet been obtained.

[0003]

SUMMARY OF THE INVENTION The present invention is excellent in moisture resistance, heat resistance and electrical properties required for small and thin electronic parts, and also improves brittleness which is a drawback of thermosetting resin molding materials. It is an object of the present invention to provide a phenol resin molding material having excellent flexibility.

[0004]

According to the present invention, the main component of the resin is a novolak type phenol resin, and an organic fiber, acrylonitrile butadiene rubber (hereinafter referred to as NB) is used as a filler.
R), which is a phenolic resin molding material having excellent flexibility, wherein the organic fiber as a filler is a crushed cloth or the like, and is 8 parts per 100 parts by weight of the resin component.
NBR as a filler is a partially crosslinked or carboxy-modified type in which the amount of bound acrylonitrile is 30 to 45%, and has a compatibility parameter value (hereinafter referred to as SP value) of 9 to 50%. The present invention relates to a phenolic resin molding material, characterized in that the phenol resin molding material is used in an amount of 5 to 25 parts by weight based on 100 parts by weight of the resin component.

The phenolic resin molding material of the present invention uses a novolak type phenolic resin as a main component of the phenolic resin, and is suitably used for thin-walled molded products and fitting parts.
However, when a novolak-type phenol resin is used as a main component, hexamethylenetetramine is usually used as a curing agent. However, since a corrosive gas such as ammonia gas is generated during curing, it is better to avoid precision parts. The number average molecular weight of the novolak type phenol resin used in the present invention is preferably from 600 to 1,000, and particularly preferably from 700 to 900. If it is less than 600, it has a low melting point and tends to solidify at room temperature, so it is not easy to handle.
If it exceeds 00, the fluidity is reduced, and the roll workability during production of the molding material is also deteriorated.

The organic fiber used as the filler is a crushed cloth or the like, and the addition amount is preferably 8 to 25 parts by weight, more preferably 10 to 20 parts by weight, based on 100 parts by weight of the phenol resin component. When added in an amount of 25 parts by weight or more, it is difficult to control the flow during the production of the molding material, and problems such as poor fluidity due to an increase in viscosity at the time of melting the molding material occur, which is not preferable. No further improvement in flexibility is observed. On the other hand, if the amount is less than 5 parts by weight, there is almost no influence on the characteristics due to the addition, which is not preferable.

The NBR used as the filler is a partially crosslinked or carboxy-modified type in which the amount of bound acrylonitrile is 30 to 45% and the SP value is 9 to 11, and the added amount is phenol resin. 5 to 25 parts by weight, more preferably 10 to 2 parts by weight, per 100 parts by weight of the components
0 parts by weight is desirable. 45% bound acrylonitrile
With the above, the hardness of the NBR itself increases, and when blended in a molding material, the improvement in flexibility is hardly obtained, which is not preferable. If the content is 30% or less, the heat resistance of NBR itself is reduced, and when incorporated in a molding material, the heat resistance of the molded product is significantly reduced, which is not preferable. NBR having an SP value other than 9 to 11 has poor compatibility with the phenolic resin, has poor dispersibility, has no effect on flexibility, and should be avoided. When the addition amount is 25 parts by weight or more, further improvement in flexibility when the molding material is formed into a molded product is not recognized, and problems such as deterioration of fluidity due to increase in viscosity at the time of melting of the molding material occur. . On the other hand, if the amount is less than 5 parts by weight, there is almost no influence on the characteristics due to the addition, which is not preferable.

In forming a molding material, in addition to the above-mentioned phenol resin and filler, a curing aid such as slaked lime, a pigment, a release agent, etc. are blended and uniformly mixed in the same manner as in the case of ordinary molding materials. A molding material can be obtained after kneading with a pressure kneader, twin-screw extrusion, kneading with a heating roll or the like and pulverizing.

The phenolic resin molding material of the present invention has excellent moisture resistance, heat resistance, and electrical properties required for small and thin electronic parts, and has improved the brittleness which is a drawback of the thermosetting resin molding material. It is a phenolic resin molding material with excellent flexibility.

[0010]

EXAMPLE A phenolic resin molding material was produced according to the formulation shown in Table 1. The properties of the molded article were measured for each molding material, and are shown in Table 2. As a comparison of flexibility, the amount of deflection in a cantilever bending test was measured and judged.

[0011]

[Table 1]

[0012]

[Table 2]

[Measurement method] Solder heat resistance: A test piece having a thickness of 50 mm x 3 mm
Transfer molding was performed at 75 ° C. for 3 minutes, immersed in a 430 ° C. solder bath for 3 seconds, and the rate of change in thickness was measured. Cantilever bending test: The distance between branches was set to 30 mm, and a test piece having a thickness of 4 mm was measured by applying a load at a speed of 5 mm / min.

[0014]

As is clear from the above Examples and Comparative Examples, the phenolic resin molding material of the present invention is excellent in moisture resistance, heat resistance and electrical properties. Furthermore, it is a phenolic resin molding material with excellent flexibility that has improved brittleness, which is a drawback of thermosetting resin molding materials, and is suitable for small thin molded products that require these characteristics, especially for fitting parts. is there.

Claims (3)

[Claims] 1. A highly flexible phenolic resin molding material characterized in that the main component of the resin is a novolak type phenolic resin, and the composition contains an organic fiber and acrylonitrile butadiene rubber as a filler. 2. The phenolic resin molding material according to claim 1, wherein the organic fiber as a filler is a crushed cloth or the like, and is contained in an amount of 8 to 25 parts by weight based on 100 parts by weight of the resin component. 3. An acrylonitrile-butadiene rubber as a filler is a partially crosslinked or carboxy-modified rubber having a bound acrylonitrile content of 30 to 45% and a compatibility parameter value of 9 to 11; The phenolic resin molding material according to claim 1, wherein the phenolic resin molding material is contained in an amount of 5 to 25 parts by weight based on 100 parts by weight of the component.