JPH03265646A - Synthetic resin composition for sliding part - Google Patents

Abstract

PURPOSE:To prepare the title compsn, exhibiting a low coefficient of friction of restarting, a stable coefficient of friction, and an excellent wear resistance by homogeneously mixing a synthetic resin with a polytetrafluoroethylene resin, a phosphate, and a reinforcing filler, each in a specified amt. CONSTITUTION:The title compsn. is prepd. by homogeneously mixing a synthetic resin (e.g. a polyamide resin) with 3-40wt.% polytetrafluoroethylene resin, 0.5-15wt.% phosphate (e.g. lithium pyrophosphate), and 1-30wt.% reinforcing filler selected from the group consisting of a glass fiber, glass powder, carbon fiber, and carbon powder. The compsn., having excellent sliding characteristics and showing a high wear resistance independently from sliding speed, is suitably used for a bearing, gear, flexible shaft liner tube, guide member, etc.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a synthetic resin composition for sliding members suitable for use in bearings, cams, gears, sliding plates, liner tubes for flexible shafts, guide members, etc. relating to things.

(Prior art) In order to improve sliding properties such as self-lubricity and wear resistance, and to improve mechanical properties such as strength, synthetic resins are generally used for sliding applications such as bearings. It is well known that polytetrafluoroethylene resin (hereinafter abbreviated as PTFE) and/or glass fiber, carbon fiber, etc. are blended.
No. 9262, JP-A-61190553, JP-A-61-
162549, JP 62-185747, JP 62-223262, JP 63-278968,
Various proposals have been made in JP-A-1-127306, JP-A-1-259059, etc.

The sliding members disclosed in these conventional techniques have improved sliding characteristics by blending a certain proportion of PTFE with the base resin, and have improved wear resistance and wear resistance by blending a certain proportion of glass fiber, carbon fiber, etc. They improve mechanical properties and are intended for use under dry friction conditions without supplying lubricating oil to sliding surfaces.

(Problems to be Solved by the Invention) However, in sliding members used under dry friction conditions, the surface (sliding surface) of a mating member, such as a shaft,
The skill with which the lubricating film is formed on the surface of the material greatly influences its performance.

However, in the sliding member disclosed in the above-mentioned prior art, it cannot be said that the formation of a lubricating film on the surface of the mating member is necessarily good, and as a result, the coefficient of friction upon restart due to intermittent operation is high, and the coefficient of kinetic friction is low. This creates a problem of instability.

In addition, various attempts have been made to improve the wear resistance and mechanical properties of sliding members by blending glass fibers, carbon fibers, etc., but since these fibers are themselves hard, the blending ratio is Particular attention must be paid to the following: if a large amount is added for the purpose of improving strength etc., it has the disadvantage of damaging the mating material or scraping off the lubricating film formed on the surface of the mating material. This results in the problem of developing abrasive wear.

The present invention has been made in order to solve the above-mentioned problems, and is a material for sliding members that has excellent ability to form a lubricating film on the surface of a mating material and has excellent sliding properties and mechanical properties. It is intended to be an acid.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention employs specific technical means (configurations).

That is, a) polytetrafluoroethylene resin 3 to 40% by weight, b) phosphate 0.5 to 15% by weight, C
) A composite material for a sliding member is made by uniformly mixing 1 to 30% by weight of a reinforcing filler selected from glass fiber, glass powder, carbon fiber, and carbon powder.

The synthetic resin used in the present invention has the mechanical properties and chemical properties required for sliding members, and if it also has wear resistance and self-lubricating properties, it can be used as a double layer. preferable. Also, depending on the application, it is preferable to have elasticity that can absorb vibrations, etc. Examples of such synthetic resins include polyacecool resin, polyamide resin, ABS resin, polyamideimide resin, polyurethane resin, polyetherimide resin, and polyethylene resin. Resin, polypropylene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyarylate resin, polyphenylene sulfide resin, polyether sulfone resin 5 polyether ether ketone resin polycarbonate resin, polyether ester resin, polyurethane resin, epoxy resin, phenol resin, etc. can be mentioned.

The PTFE blended into the base resin contributes to the self-lubricity and low friction properties of the base resin, and suitable PTFE in the present invention includes, for example, "Teflon 7JJ, r Teflon 7
AJJ, product name "Rubloon L-2" manufactured by Daikin Industries, Ltd.
Examples include "Rublon L5", "Rublon LD-IJ", and rKTL-610J (trade name, manufactured by Kitamura Co., Ltd.).

The blending ratio of PTFE to the base resin is 3~
40% by weight, especially 10-25% by weight is preferred.

At a blending ratio of 3% by weight with no grooves, the self-lubricity of the base resin,
It has no effect on low friction properties, and if it is added in an amount exceeding 40% by weight, moldability deteriorates and mechanical strength decreases.

Phosphate itself is not a substance that exhibits lubricity like graphite, but by blending it with the aforementioned PTFE in the base resin, it works in conjunction with 89PTFE to improve the friction and wear characteristics of the base resin. demonstrate. It is not clear why the friction and wear characteristics are improved by the addition of phosphate, but in a sliding member in which PTFE and phosphate are simultaneously added to the base resin, the surface of the mating material (sliding) after the sliding friction test is Based on the fact that a lubricating film composed of a base resin, PTFE, and phosphate was formed on the moving surface, the inventors concluded that the effect of this phosphate on improving friction and wear characteristics was due to the lubricating film. It is assumed that this is due to its excellent film-forming properties.

Phosphates used in the present invention include metal salts such as tertiary phosphoric acid, diphosphoric acid, birophosphoric acid, phosphorous acid, metaphosphoric acid, and mixtures thereof, among which tertiary phosphoric acid, It has been confirmed that metal salts of diphosphoric acid and birophosphoric acid are preferable in terms of the film-forming properties of the above-mentioned lubricating film.

Preferred metals are alkali metals or alkaline earth metals, particularly lithium (Li), calcium (Ca), magnesium (Mg), and barium (Ba).

Phosphate starts to exhibit a film-forming effect for a lubricating film when the blending ratio is small, for example, 0.5% by weight, and the film-forming effect is maintained up to a blending ratio of 15% by weight. but,
If the amount exceeds 15% by weight, the amount of lubricating film formed will be too large, which will actually reduce the wear resistance.

Therefore, the blending ratio of phosphate is 0.5 to 15% by weight.
, particularly preferably 3 to 10% by weight.

Glass fiber, glass powder, carbon fiber, and carbon powder as reinforcing fillers are blended into the base resin, and play a role of particularly improving the mechanical strength of sliding members and increasing the surface hardness of the sliding surfaces of sliding members. plays a role in improving wear resistance.

The blending ratio of these reinforcing fillers is 1 to 30% by weight, especially 5% by weight.
~20% by weight is preferred.

In general, mixing a large amount of reinforcing filler should be avoided because it damages the mating material during sliding with the mating material and causes abrasive wear due to the interposition of abrasion powder. However, in the present invention, Due to the above-mentioned film-forming effect of the lubricating coating of phosphate, direct contact between these reinforcing fillers and the mating material can be prevented, so it is possible to incorporate a large amount of 30% by weight.

Glass fibers used as reinforcing fillers include glass fibers conventionally used in the art, such as amorphous silicate glass, borate glass, etc., as well as wollastonite and titanium. Potassium acid whiskers and the like can also be used.

Carbon fibers include polyacrylonitrile, rayon,
Carbon fibers made from polyvinyl alcohol, phenol, pitch, etc. as starting materials are used.

These fibers have a diameter of 1 to 20 μm, especially 5 to 15 μm.
m, the length is 20 to 6000 μm, especially 50 to 3
00 μm is suitable.

As the glass powder, a powder made of the above-mentioned amorphous silicate glass, borate glass, etc. is used.

The carbon powder is a powder made by heat-treating amorphous carbon powder such as coke powder, anthracite powder, carbon black powder, charcoal powder, or polymer compound powder such as phenol resin powder at a temperature exceeding 550°C in an inert atmosphere (Kanebo Co., Ltd.). The company's product name ``Helpearl'') is used.

The particle size of these powders is 100 μm or less, especially 1 to 40 μm.
m is used.

The synthetic resin composition for sliding members of the present invention consists of the above-mentioned component compositions, but in addition to these component compositions, in order to further improve moldability, wear resistance, and load resistance, for example, Solid lubricants such as molybdenum disulfide and graphite, soft metals such as lead, etc. can be blended in a proportion of 5% by weight or less.

(Example) Examples of the present invention will be described below.

Example 1.2.3, Comparative Example 1: Polyamide resin (hereinafter referred to as PA, manufactured by Square Co., Ltd., product name:
Nylon 66C gate 3001N J”) powder, PTF
E (manufactured by Daikin Industries, Ltd., trade name: ``Luburon L5'') powder, glass fiber (hereinafter referred to as GP), carbon powder (hereinafter referred to as c
P) or carbon fiber (hereinafter referred to as CF) and a mixed powder obtained by mixing phosphate powder as a molding material,
This is molded using a screw in-line injection molding machine at a molding temperature of 250 to 290°C and an injection molding pressure cuff of 00 kg.
Molded under the conditions of /cni, - side is 30mm and thickness is 5m
A rectangular test piece of m was obtained.

Example 4.5.6, Comparative Example 2: Polyphenylene sulfide resin (hereinafter referred to as PPS, manufactured by Nidoprene Co., Ltd., trade name rT-4J) powder was coated with the PT.
A mixed powder obtained by mixing FE powder, GF, CF or CP, and phosphate powder is used as a molding material, and this is molded using a screw in-line injection molding machine at a molding temperature of 27.
It was molded under the conditions of 0 to 300°C and an injection molding pressure of 800 kg/ci to obtain a rectangular test piece with a side of 30 mm and a thickness of 5.

Example 7.8: A mixed powder obtained by mixing the PTFE powder, GF or CP, and phosphate powder with polycarbonate resin (hereinafter referred to as PC; manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Nipilon 52000 J") powder was mixed. The molding material is molded using a screw in-line injection molding machine at a molding temperature of 250 to 300°C and an injection molding pressure of 1000 kg/
A rectangular test piece having a negative side of 30 mm and a thickness of 511 m was obtained by molding under CD conditions.

Example 9, lO1 Comparative Example 3: Phenol resin (hereinafter referred to as PH: manufactured by Showa Union Gosei Co., Ltd., trade name rBRP-520J) powder was added with the PTF.
A mixed powder obtained by mixing E powder, CF or CP, and phosphate powder was used as a molding material, and this was molded using a compression molding machine at a molding temperature of 160°C and a molding pressure of 200 kg/d. A rectangular test piece with a diameter of 30 mm and a thickness of 5 mm was obtained.

A thrust test was conducted on the molded products obtained in each of the above Examples and Comparative Examples under the following conditions, and the results are shown in the table.

Sliding speed: 20m/min Load: 10kg/cm2 Mating material: SOS 304 (outer diameter 25.5mm, inner diameter 20.0mm) 11800 emery finish Sliding: Non-lubricated time: 24Hr In the table, a is PTFE, b is PTFE Phosphate, C is a reinforcing filler. Furthermore, the friction coefficient indicates the fluctuation range after one hour from the start of the test.

(The following is a blank space) From the test results described above, the test pieces of Examples 1 to 10 exhibited a stable and low coefficient of friction throughout the test period compared to the comparative example, and the amount of wear also showed an extremely small value.

(Effects of the Invention) As explained above, the composition of the sliding member base cord sole composition of the present invention has a low friction coefficient upon restart, a stable dynamic friction coefficient, and is resistant to wear regardless of the sliding speed. Bearings, cams, and gears.

It exhibits good performance when used in sliding plates, liner tubes for flexible shafts, guide members, etc.

Claims (1)

[Scope of Claims] 1) Synthetic resin, a) 3 to 40% by weight of polytetrafluoroethylene resin, b) 0.5 to 15% by weight of phosphate, c) Glass fiber, glass powder, carbon fiber, A synthetic resin composition for a sliding member, which is made by uniformly mixing 1 to 30% by weight of a reinforcing filler selected from carbon powder. 2) The synthetic resin composition for a sliding member according to claim 1, wherein the phosphate is an alkali metal or alkaline earth metal phosphate. 3) The synthetic resin composition for a sliding member according to claim 2, wherein the phosphate is at least one of lithium phosphate, calcium phosphate, magnesium phosphate, and barium phosphate.