JPS61136531A - Abrasion-resistant molding material - Google Patents

Abstract

PURPOSE:A molding material excellent in lubricating/sliding property and abrasion resistance, obtained by adding fine silicon nitride particles to a thermosetting or thermoplastic plastic material. CONSTITUTION:An abrasion-resistant engineering plastic molding material is obtained by adding 15-50wt% fine silicon nitride particles, preferably, trigonal alpha-silicon nitride of an alpha-form content >=70% and an average particle diameter <=20mum, surface-treated with a silane coupling agent and, optionally, 5-10wt% auxiliary reinforcement (e.g., carbon fiber, and additives such as a cure accelerator and an insulating agent to a thermosetting molding material (e.g., phenolic resin) or a thermoplastic plastic material (e.g., polyether sulfone resin).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to wear-resistant molding materials, and more specifically, to the lubricating sliding properties of thermosetting or thermoplastic plastic materials kneaded with silicon nitride fine particles. Regarding superior engineering plastic molding materials.

[Prior art and its problems]

As plastic molding materials having this type of lubricating sliding property, thermosetting and thermoplastic molding materials kneaded with fillers such as carbon fiber, graphite powder, and fluororesin powder are known.

However, although carbon fiber and graphite powder improve sliding properties, they have the disadvantage that electrical insulation properties are significantly reduced, and their range of use as materials for electrical equipment is limited. Further, in the case of fluororesin powder, the thermal conductivity is low, the sliding properties (particularly the wear properties) cannot be improved in spite of the amount added, and the dispersibility in plastic molding materials is also poor. In this way, the above-mentioned types of plastic molding materials are still not sufficient in terms of contact reliability for molded parts such as small relays with mechanical sliding parts and control devices such as electromagnetic switches. ,
In addition, there is a problem in that the screws, cylinders, etc. of the molding machine are worn out when molding these molded parts.

[Purpose of the invention]

By using silicon nitride fine particles with excellent insulation and thermal conductivity as a filler, the present invention provides a stable lubricating and sliding effect for long-term use of molded parts. An object of the present invention is to provide a molding material that can reduce wear on screws, cylinders, etc. of a molding machine.

[Key points of the invention]

The present invention relates to an engineering plastic molding material having excellent lubricating and sliding properties, which is made by adding silicon nitride fine particles to a thermosetting plastic molding material or a thermoplastic plastic material.

In the present invention, the filler added to improve the sliding properties of the plastic D-shaped material is silicon nitride (S i
2N, -) fine particles. Particularly preferable silicon nitride fine particles are trigonal α-silicon nitride with an alpha conversion rate of 70% or more and an average particle size of 20 μ- or less.

It is in the form of a fine powder. The silicon nitride fine particles are added in an amount of 15 to 50% by weight based on the plastic material. It is particularly preferable that the silicon nitride fine particles be surface-treated with a silane coupling agent or the like in order to improve their dispersibility in plastic materials.

Silicon fine particles are easily available on the market.

Thermosetting plastic materials to which silicon nitride fine particles can be added according to the present invention include phenolic resins, epoxy resins, unsaturated polyester resins, melamine resins, xylene resins, and the like.

Examples of the thermoplastic material include polycarbonate resin, polyether sulfone resin, polyphenylene sulfide resin, polyamide resin, and polyacetal resin.

When mechanical strength is required for the molding material according to the present invention, an auxiliary reinforcing material such as carbon fiber in an amount of, for example, 5 to 10 f (11%) of the molding material may be added to the extent that the insulation properties are not impaired. It goes without saying that other additives such as other reinforcing materials, curing catalysts or accelerators, colorants, insulating agents, stabilizers, etc. can also be added depending on the type of molding material. .

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Using polyether sulfone or polyphenylene sulfide resin as a plastic molding material, adding a-silicon nitride fine particles and carbon fiber reinforcing material to this,
This resin composition, which was thoroughly kneaded and uniformly dispersed in the resin, was then injection molded into a predetermined shape under the conditions of a cylinder temperature of 320°C or 340°C and a mold temperature of 100°C or 120°C. After a cooling (hardening) time of seconds, test specimens according to the invention were prepared.

Table 1 summarizes the types and amounts of resin, silicon nitride, and reinforcing materials used to create the test pieces, as well as the molding conditions.

Furthermore, reference test specimens 1 and 2 were produced by molding in the same manner using the resin described above but without adding silicon nitride fine particles.

A sliding abrasion test was conducted to evaluate the abrasion resistance of each of the test pieces prepared as described above. As shown in FIG. 1, this test used a movable side test piece I with a circular cross section and a fixed side test piece 2 with a V-shaped recess, each made of the same molding material. The fixed side test piece 1 is fitted into the recess of the fixed side test piece 2, and the two are brought into contact with each other, and the movable side test piece 1 is placed under a constant load W (W-3krf).
was rotated at a rotational speed of 60 rpm for 24 hours, and the sum (mg) of the amount of sliding wear generated from both test pieces 1 and 2 was determined.

The results of the abrasion test for each test piece of Examples 1 to 4 and reference test pieces 1 and 2 are shown in FIG.

C Effect of the invention] According to the invention, trigonal α-silicon nitride (α-ization rate 70
% or more) with an average particle size of 20μ or less, which has been treated with silane, so that it can be uniformly dispersed in plastic materials and can be added in large quantities, making it suitable for molding materials. The wear characteristics have been significantly improved.

In addition, since carbon fiber was used as the auxiliary reinforcing material, it was possible to improve the mechanical strength of the molding material without reducing the wear characteristics as in the case of glass fiber.

[Brief explanation of the drawing]

Fig. 1 shows an overview of the abrasion resistance test method for molding materials of the present invention, in which 1 shows a movable side test piece, 2 shows a fixed side test piece, and Fig. 2 shows a molding material of an example. It is a graph comparing the wear characteristics (total wear amount) of Patent applicant Fuji Electric Co., Ltd. Ki 1a 1f Arithmetic 2 eyes rprn 3 to 7f

Claims (1)

[Claims] 1) A wear-resistant molding material characterized by adding silicon nitride fine particles to a thermosetting plastic material or a thermoplastic plastic material. 2) The molding material according to claim 1, wherein the silicon nitride is trigonal α-silicon nitride with a gelatinization rate of 70% or more. 3) The molding material according to claim 1 or 2, wherein the silicon nitride fine particles have an average particle size of 20 μm or less. 4) The molding material according to claim 1 or 2, wherein the silicon nitride fine particles are surface-treated with a silane coupling agent. 5) In the molding material according to claim 1 or 2, the silicon nitride fine particles are 15% of the plastic material.
Molding material, characterized in that it is added in an amount of ~50% by weight. 6) The molding material according to any one of claims 1 to 5, characterized in that 5 to 10% by weight of carbon fiber is further added to the plastic material.