JPH0277493A - Lubricating composition - Google Patents

Abstract

PURPOSE:To obtain the title composition satisfying both functions, i.e., wear resistance and electrical conductivity at elevated temperatures by incorporating a polyphenylene sulfide resin with graphite, tetrafluoroethylene resin and carbon black at each specified amount. CONSTITUTION:A polyphenylene sulfide resin is incorporated with, as the essential components, (A) 10-30wt.% of graphite, (B) 10-35wt.% of tetrafluoroethylene, and (C) 2-10wt.% of carbon black using a mixer such as Henschel mixer or ball mill in a dry state, and the resultant blend is then fed into e.g., an injection molding machine, thus obtaining the objective composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubricating composition containing polyphenylene sulfide resin as a main component and used as a material for various sliding parts.

[Conventional technology]

In recent years, as the field of application for synthetic resin sliding bearings has expanded, there has been a strong demand for heat-resistant synthetic resin bearings that exhibit good S friction characteristics under the conditions in which the bearings are used, especially in high-temperature atmospheres. It has become.

It is well known that polyphenylene sulfide (abbreviated as PPS) resin has been used as a thermoplastic synthetic resin with good heat resistance and mechanical strength. However, this PPS resin has poor self-lubricating properties, so when using it as a material for parts that require lubricity,
It is necessary to add a lubricant to provide lubricity, and for example, composite materials using graphite, tetrafluoroethylene resin, lubricating oil, metal oxides, aromatic polyamide resin, etc. have been developed. However, such composite materials can withstand high temperatures,
It can never be said that it is sufficient in terms of exhibiting very good friction and wear characteristics under high load conditions.On the other hand, composite materials containing carbon fibers exhibit good friction and wear characteristics at the initial stage, but damage to the material, and as a result of the damage, the friction and wear characteristics become 2. It gets drastically worse.

[Problem to be solved by the invention]

As described above, the conventional technology has the problem that it cannot meet the demands of the public because there is no heat-resistant material with good lubrication properties, and it has been an issue to solve this problem.

[Means to solve the problem]

In order to solve the above problems, this invention adds 10 to 30% by weight of graphite to PPS resin and 10 to 30% by weight of tetrafluoroethylene resin.
The lubricating composition is prepared by adding up to 35% by weight of carbon black and 2 to 10% by weight of carbon black as essential components, and the details thereof will be described below.

First, the PPS resin in this invention is a synthetic resin represented by the general formula %. Here, -ph- is in the formula, and Q is FSCl, halogen of Br, or CHs
, where m is an integer from 1 to 4. Among these, the most typical one is commercially available from Phillips Vetroleum Company in the United States under the trademark "Rydon," and its manufacturing method is based on the United States. It is disclosed in Japanese Patent No. 3,354,129 (corresponding Japanese Patent Publication No. 45-3368). according to it,
Lydon is 160-25 in N-methylpyrrolidone solvent.
It is produced by reacting p-dichlorobenzene and sodium disulfide under pressure at 0°C, and the resin has various degrees of polymerization, ranging from no cross-linking to partial cross-linking. Since it is possible to freely manufacture products by subjecting them to a post-heat treatment process, it is possible to arbitrarily select and use materials with appropriate melt viscosity characteristics for the desired solvent blend.

Next, the graphite used in this invention can be earth-like, scaly-like,
It may be either lumpy or spherical natural graphite or artificial graphite (coal coke type, petroleum coke type, pitch type, etc.).

Further, the tetrafluoroethylene lubricant in this invention is a polymer of tetrafluoroethylene, and may be a powder for molding or a fine powder for so-called solid lubricants, such as Mitsui Manufactured by DuPont Fluorochemical Company: Teflon 7J, TLP-10, Manufactured by Asahi Glass Company: Fluon G163,
Examples include Polyflon M15 and LeBlon Shi5 manufactured by Daikin Industries.

In addition, carbon black in this invention includes Ketschen black, acetylene black, furnace black,
Examples include lamp blanks, thermal blacks, channel blacks, roll blacks, and disc blacks.

In this invention, the reason why the amount of graphite is limited to 10 to 30% by weight is that the lubricating properties are poor outside this range, and the reason why the amount of tetrafluoroethylene resin is limited to 10 to 35% by weight is that the amount of graphite is limited to 10 to 30% by weight. If it is less than 3% by weight, the lubricating properties are poor;
This is because if the amount exceeds 5% by weight, the moldability will be significantly impaired.Furthermore, the reason why the amount of carbon black is limited to 2 to 10% by weight is that if the amount of carbon black is less than 2% by weight, the lubricating properties are poor. If it exceeds this, the lubrication properties may deteriorate again.
This is because it becomes brittle, which is not desirable.

Here, the method of mixing each additive with a fixed blending ratio is not particularly limited, and any commonly used method may be used, such as mixing the main component resin and other raw materials individually, or using a Henschel mixer. , ball mill,
After dry mixing as appropriate using a mixer such as a tumbler mixer, the mixture is supplied to an injection molding machine or melt extrusion molding machine with good melt mixing properties, or it is melted in advance using a heated roll, kneader, Banbury mixer 1 melt extruder, etc. Furthermore, the method of molding the composition of the present invention is not particularly limited, and conventional methods such as compression molding, extrusion molding, injection molding, etc., or composition molding may be used. After melting and mixing the materials, it is pulverized using a jet mill, frozen pulverizer, etc., and classified to the desired particle size, or the resulting powder is used for fluidized dip coating, electrostatic powder coating, etc. It is also possible to perform painting.

Note that various additives may be added to the lubricating composition of the present invention which has the PPS resin as a main component within a range that does not deteriorate the lubricating properties.

[Function] The composition of the present invention described above contains graphite,
By using tetrafluoroethylene resin and carbon black together, it exhibits good lubrication properties, and at the same time, since no hard materials are added, it does not damage the mating material.
Further, conductivity can also be imparted by adjusting the amounts of graphite and carbon black.

〔Example〕

First, the raw materials used in the Examples and Comparative Examples are listed below. The blending ratio of each component is
All percentages are by weight.

■ PPS resin (manufactured by Tososa Steel Co., Ltd.: PPS#
140), ■ PPS resin (manufactured by Kureha Chemical Co., Ltd.: KPS-W2O3
), ■ Spheroidal graphite (manufactured by Osaka Gas Co., Ltd.: Mesogorbon beads fired at 2800°C, average particle size 6j!m), ■ Scaly graphite (manufactured by Nippon Graphite Co., Ltd.: ACP), ■ Carbon fiber (manufactured by Toshisha Co., Ltd.) : Trading card MLD-30), ■ Talc, ■ Tetrafluoroethylene resin (manufactured by Mitsui DuPont Fluorochemical Co., Ltd.: Teflon 7J), ■ Carbon blank (manufactured by Lion Corporation: Ketjen Black EC-X), Examples 1 to 4 : Various raw materials were blended in the proportions shown in Table 1. To mold the composition, first, the raw materials are thoroughly mixed in a Henschel mixer, then fed to a twin-screw melt extruder, and extruded and granulated at a cylinder temperature of 300°C and a rotation speed of 100 revolutions per minute. The pellet was heated to a resin temperature of 310″C.
1 Under injection molding conditions of injection pressure 800 kg/cj and mold temperature 130°C, outer diameter 23 m, inner diameter 14 m, length 13
A ring-shaped test piece was molded, and volume resistivity measurements and friction and wear tests were performed using this test piece. Also, the coefficient of friction is the sliding speed at 100-1 load per minute, 1 kg/c-
The wear coefficient was measured using a thrust type friction tester under the following conditions, and the wear coefficient was determined using a thrust type wear tester under the conditions of a sliding speed of 128 cm/min and a load of 3.9 kg/cd. Steel 5UJ-2 (quenched and ground finished) was used. The results obtained are summarized in Table 2.

The degree of damage to the mating material was examined after the wear test, and the results are also listed in Table 2. Regarding the degree of damage, there is no damage (O
It was expressed on a two-level evaluation: (marked) and damaged (marked x).

Comparative Examples 1 to 4: Test specimens were made in the same manner as in Example 1 except that the raw materials were mixed in the proportions shown in Table 1, and the properties of the specimens were determined. The obtained results are also listed in Table 2. .

From the results shown in Table 2, Comparative Examples 1 to 3 had high wear coefficients, and although Comparative Example 4 showed good lubrication properties, the mating material was damaged, and the wear coefficient was high as in Examples 1 to 4. It has become clear that it is not possible to obtain a composition that does not cause small damage to the mating material.

Table 2 [Effects] As mentioned above, the molded product obtained from the composition of the present invention has excellent abrasion resistance and is also secondarily imparted with electrical conductivity. Taking advantage of its heat resistance, it can be said to be ideal for applications that require both wear resistance and conductivity at high temperatures. In addition, since injection molding is also possible and molding is easy, it can be said that the significance of this invention is extremely large.

Claims (1)

[Claims] (1) Polyphenylene sulfide resin, graphite 10~
1. A lubricating composition comprising 30% by weight of a tetrafluoroethylene resin, 10 to 35% by weight of a tetrafluoroethylene resin, and 2 to 10% by weight of carbon black as essential components.