JPS60228558A - Polyphenylene sulfide resin composition - Google Patents

Abstract

PURPOSE:The titled resin composition having good frictional characteristics, and excellent heat resitance, abrasion resistance, and moldability, suitable for the manufacture of a friction material, containing specified quantities of a lubricant and cleavable inorganic filler. CONSTITUTION:30-70wt% polyphenylene sulfide resin (e.g. Ryton-PPS-P-4 by Phillips Petroleum Co.), 5-15wt% polytetrafluoroethylene resin (preferably particulate), 1-5wt% molybdenum disulfide (preferably particulate), 10-25wt% cleavable inorganic filler (e.g. talc, mica or graphite, having particle diameters of about 0.1-50mum), and 10-25wt% fibrous reinforcement (e.g. carbon fibers of a length of about 6mm. or potassium titanate fibers) are compounded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention consists of polyphenylene sulfide resin (hereinafter referred to as 22-day resin), polytetrafluoroethylene resin (hereinafter referred to as pTIPm Ia4 resin), binary molybdenum, an inorganic filler having hexagonal property, and a fibrous Item 4 relates to a molding composition that contains a filler in a certain proportion and has good sliding performance and can be highly applied as a sliding member with excellent heat resistance, abrasion resistance, moldability, etc.

In recent years, synthetic resins have been increasingly used for sliding members such as bearings due to their light weight and ease of processing.

Among synthetic resins, thermoplastic resins such as polyethylene resins, polypropylene resins, polyacetal resins, and polyamide resins have excellent moldability and abrasion resistance, and are therefore being put into practical use as sliding members. Although the self-lubricating properties of such synthetic resins are higher than that of rubber, they are significantly inferior to fluororesins such as FTFFi resins, and it is necessary to incorporate Fia lubricant to improve sliding properties. Among such thermoplastic resins, molded products made of sliding materials containing polyethylene resin or polypropylene resin with a lubricant will deform when the temperature rises during use, since the heat distortion temperature of the polyethylene resin or polypropylene resin itself is low. Molded products made of polyacetal resin mixed with a lubricant also have excellent sliding properties, but have poor heat resistance, and have a large mold shrinkage rate that makes them unsuitable for precision molded products. . Also,
FTFFi resin, which has lubricating properties, softens as the temperature rises and tends to adhere to the sliding surface of a mating member.As a result, wear progresses rapidly, which limits the field of use. Furthermore, polyamide resins, which are relatively heat resistant, have water absorption properties, which poses a problem in the dimensional stability of molded products.

Under these circumstances, office automation has recently progressed rapidly, and sliding members used in so-called zero-meter equipment used in connection with this have high heat resistance, a high degree of dimensional stability, and are capable of precision molding. Molding compositions are strongly recommended.

Thermoplastic resin with high heat resistance and excellent mechanical strength
PPl3 resin is now being put to practical use in the field of engineering plastics.

Although such pps resin is a thermoplastic resin, it has properties similar to a thermosetting resin that can be crosslinked by heating, etc., and it has excellent moldability and chemical resistance as well as heat resistance and mechanical strength. However, pps resin alone has low elongation and is brittle, so it is used as a molding material, and the form of pps resin is usually reinforced by adding reinforcing materials or reinforcing agents. Further, since the pps resin itself has poor self-lubricating properties like the above-mentioned thermoplastic resins, when used as a sliding member, it is necessary to impart sliding properties by adding a lubricant or the like.

Generally, as a means to improve the sliding properties of synthetic resins, finely powdered solid lubricants such as #1 PTFI resin, graphite, molybdenum disulfide, and boron nitride are blended, and silicone oils and fluorinated oils that are liquid at room temperature are mixed. Methods of adding synthetic oils such as mineral oils, etc., have been adopted.

In various attempts to impart sliding properties to pps resin, a sliding member made by adding graphite, FT, and F'E resin to PP8 resin was proposed in Japanese Patent Application Laid-open No. 52-129761. Also, in Japanese Patent Publication No. 57-13586, PP8
A PP8 resin composition containing a resin, molybdenum disulfide, and carbon pa, ta is disclosed. However, the former sliding members have a high content of graphite and p T F Km fat, which increases the amount of wear of the members, and because they do not contain reinforcing materials, their mechanical strength is low, limiting the field of use. Furthermore, since sliding members made of the latter composition have a high content of molybdenum disulfide and carbon fiber, the amount of wear on the member is large, and the limit pv value during sliding is low, so it is difficult to withstand loads. It has the disadvantage of low resistance to resistance and speed.

In view of the above-mentioned problems, the present inventors have studied and researched various means to impart low friction properties to PP8 resin, which has high heat resistance and excellent mechanical strength, and to increase wear resistance and critical pv value. As a result, graphite, F
This is because low-friction imparting agents such as TFB resin and molybdenum disulfide are contained in large amounts, and reducing the amount of these agents improves wear resistance, but increases the coefficient of friction. On the other hand, it contains a large amount of a low friction agent,
It has been found that the inclusion of glass fiber, glass beads, silica, etc. for the purpose of improving wear resistance damages the mating member. For these reasons, the content of the KJd low-friction imparting agent, which improves sliding performance such as low friction and wear resistance, without damaging the mating member, is limited within a specific range, and the cleavage property is The present invention was completed based on the discovery that it is extremely effective to contain the inorganic filler in an amount within a specific range.

The polyphenylene sulfide resin of the present invention is 30 to 70% by weight, polytetrafluoroethylene resin powder is 5 to 15% by weight, molybdenum disulfide is 1 to 5% by weight, and an inorganic filler with cleavage property is 10 to 25% by weight. Heavy fibrous reinforcement 10
It is a polyphenylene sulfide resin composition weighing ~25 kg.

Polymers consisting of repeating units represented by the pps resin general formula (0S) used in the composition of the present invention, and containing 90 mol or more of repeating units of the general formula, are preferred from the viewpoint of properties. If the number is less than 90 moles, there is a tendency to obtain a composition with specific properties.

Various known methods can be used for the polymerization method to obtain this polymer. It is preferable to carry out the reaction in a sulfonic solvent. The copolymerization component may contain less than 10 molti of copolymerization components such as sulfide bonds < (missing s-), which affect the crystallinity of the polymer. PP8 resin is in powder form, and if the particle size becomes large, gas will be generated during molding, which will increase the occurrence of cracks and voids in the initial moving member, and if the particles are too fine, the pps resin particles will tend to fall off. Among such pps resins, 1Rydon PPS F-4 or PR-0, which is commercially available from Phillips Petroleum Company of the United States, is used.
6' (trade name) is preferably used. PP8 resin containing 30 to 70% by weight in the composition improves precision moldability, heat resistance, sliding properties, and abrasion resistance of molded sliding members.
Suitable for other properties.

The composition of the present invention includes both PPS resin and PPS resin as resin components.
Contains TFE resin. FTFI resin has excellent heat resistance, and when added to pps resin, it contributes to lowering the coefficient of friction of molded sliding members, but adding a large amount will cause wear of the sliding members, so it is necessary and sufficient. It is preferable that the composition is 5 to 15 yen
, bone chi is appropriate. If the addition exceeds 15% by weight, in addition to the above-mentioned abrasion of the sliding member, the fluidity of the resin composition during molding will decrease, making it unsuitable for molding precision sliding members.
If it is less than % by weight, it will not contribute to lowering the coefficient of friction and the sliding properties will be poor. It is sufficient that the FTFFi resin is in the form of a powder that is used for ordinary molding, but it is preferable that it be in the form of fine particles.

Molybdenum disulfide is pp in the resin composition of the present invention.
Shows excellent affinity for S resin, FTFI resin, fibrous reinforcement, etc. The molybutene disulfide used is preferably in the form of fine particles, and its content in the resin composition, together with the content of the cleavable inorganic filler, affects the sliding properties of the molded sliding member. However, it is a warabi ton that weighs between 1 and 5 pounds. If more than 5% by weight of the element is added, the molded sliding member becomes brittle, the amount of wear increases, and the wear resistance becomes poor.

The cleavable inorganic filler 1 contained in the resin composition of the present invention is extremely useful for satisfying the following basic requirements as a sliding member.

(1) In terms of sliding properties, the coefficient of friction is small (2) It does not wear out the mating member (3) It has a small amount of wear on itself due to long-term durability The characteristics of the resin composition of the present invention are that it has a high cleavage property. The reason is that it contains an inorganic filler that has Normally, crystals and rocks are mechanically struck, and if there is a direction in which the bonds in their internal structure are relatively weak, they will crack parallel to the plane perpendicular to the kneading, or they will peel off. This type of parallel cracked or peeled surface is called a cleavage surface. Hexapatency.

When the resin composition of the present invention contains an inorganic filler ore having an inorganic filler ore and is molded into a sliding member, even if it is scraped during the sliding operation, it will be removed one by one from the hexagonal surface! 11
Since it wears out as if it were being removed, there is no change in the mating member. Mononoke talc, mica, clay, graphite, etc., which can be suitably used as the inorganic filler having such cleavability, include monomer talc, mica, clay, and graphite. These are not limited to one type, and two or more types may be used in combination. Also, these particle sizes are 0
．． 1 to 50μ, preferably α5 to 10μ.

The appropriate content in the resin composition is 10 to 25 F-Ill, and if the content exceeds this range, the fluidity will decrease during molding of sliding members, so K is not suitable for molding precision parts. It's not appropriate. Further, if the amount of contact is less than this range, the wear resistance of the molded sliding member will be poor and the amount of wear will increase. By containing an inorganic filler with cleavage properties, it is possible to reduce the content of PTFE resin and molybdenum disulfide, which are undesirable when contained in sliding members, and as a result, the sliding member The basic conditions (1) to (3) for moving members are satisfied.

A fibrous reinforcing material is contained for the purpose of improving the mechanical strength of the sliding member molded from the resin composition of the present invention. Glass fibers are usually used as a fibrous reinforcing material for PP8 resin, but the inclusion of glass fibers in sliding members is not preferable because it causes damage to the mating member and accelerates wear. Carbon fibers, potassium titanate fibers, and combinations of these fibers can be suitably used as the fibrous reinforcing material contained in the resin composition of the present invention.

Such complex reinforcements are generally commercially available in length 6fi.
A certain amount of chopped fiber is used. The amount contained in the resin composition is 10 to 25 parts by weight, and if it is contained in an amount within this range, the flowability during molding will be reduced, and even if it is contained in an amount exceeding the required amount, the mechanical strength will be decreased. cannot be expected to improve. In addition, if the content is in a small amount that does not fall within the above range, I/
i Mechanical strength is low, so it is not suitable.

In the resin composition of the present invention, there are no particular limitations on the method of blending and mixing the PP8 resin, PTFE resin, molybdenum disulfide, cleavable inorganic filler, and fibrous reinforcing material, and the method is usually in the form of a powder. A mixer used for mixing things,
For example, a method of uniformly mixing mechanically using a Henschel mixer, a tumbler mixer, a V-type mixer, etc. can be used. Next, pour the mixture into a set of screws.
Put it into a kneading extrusion molding machine with two screws, and
After melt-kneading and extruding into a strand while heating at a high temperature of .degree. C., it can be cooled and made into a pellet-like molding material using a pelletizer.

The pellet thus obtained can be molded into a desired shape using a commonly used thermoplastic resin molding machine, such as an injection molding machine, a compression molding machine, or an extrusion molding machine. The molding conditions in this molding method are not particularly limited and may be carried out under normal molding conditions.

Since the resin composition of the present invention has excellent fluidity during molding, it is suitable for molding precision parts that require dimensional accuracy, and also has excellent heat resistance and mechanical strength for molded sliding parts. Therefore, there is no change in shape during sliding operation, and sliding performance against abrasion can be maintained over a long period of time. The sliding performance against friction is expressed by the friction coefficient μ, which is less than α2, and without using any other lubricity imparting agent.
It can be used as a sliding member of machinery, and is particularly suitable for use as a sliding member of OA equipment. Furthermore, it does not damage the mating parts, such as the sliding shaft, and has the advantage of contributing to cost reductions, such as eliminating the need for frequent replacement of the sliding shaft, which conventionally required expensive materials. .

The present invention will be explained in more detail below using Example 9, but it goes without saying that the present invention is not limited only to these Examples. In the Examples, the sliding performance was evaluated under the following conditions.

Friction coefficient and wear coefficient: load 4.2 kg 7 cm", friction speed 60 m / Wins mating part 8450 hard chrome plated finish.

Limit pv value: cloth rubbing speed 60yq/min, mating member 84
5C hard chrome plating finish, load is variable.

Example 1 PP Nippon Resin 1 Rydon PP8'' (trade name: P-4 grade, product of Phillips Petroleum, USA) 45 parts (parts by weight, same hereinafter), PTFFi resin (L-169)
, Asahi Fluoropolymer Co., Ltd. product) 12 parts, binarized molybdenum (powder grade, Sumiko lubricant product) 3 parts, Merck as an inorganic filler with cleavage property (P-2, Matsuzai Sangyo product)
20 parts and 20 parts of carbon fiber (M-102, Kureha Kagaku Co., Ltd. product) dried at 150°C for 5 hours as a fibrous reinforcement material.
Mixed for 5 minutes using a mold mixer. The resulting light mixture is 40
The mixture was put into the hopper K of a -φ single-screw extruder, and the cylinder temperature was set at 310° C. for kneading, followed by extrusion to form pellets. After drying the pellets thus obtained at 120°C for 12 hours, they were injected into a metal mold with a mold temperature of 125°C in a 1-ounce injection molding machine with a cylinder temperature of 320°C. , inner diameter 2α diameter, outer diameter 25.6m
A cylindrical test piece for evaluating sliding performance with a length of 15 m and a length of 15 mm was molded. Using this test piece, sliding performance such as friction coefficient, wear coefficient, limit pv value, and presence or absence of damage to the mating member was measured. The results are shown in Table 1.

As shown in Table 1, it was confirmed that products with excellent wear characteristics could be obtained.

Examples 2 to 4 Talc, the inorganic filler with cleavage properties in Example 1, was mixed with mica (powder, Kagaya Kaolin product) and graphite (F-
3. Nippon Graphite Industries Co., Ltd. product) and clay (KN Kaolin, Ueya Kaolin product) were mixed and kneaded in the same manner as in Example 1 to obtain pellets. The obtained pellets were molded into test pieces for evaluating tank dynamic performance using an injection molding machine. The sliding performance of this test piece was measured and the results shown in Table 1 were obtained. As shown in Table 1, it was confirmed that products with excellent wear characteristics could be obtained.

Comparative Examples 1 to 2 Talc, an inorganic filler with cleavage property that is inferior to Example 1, was replaced with silica 1-Imucil A-10H' (trade name: Tatsuchiri Co., Ltd. product) or glass as an inorganic filler without cleavage property. Pieces (average particle size 17μ, manufactured by Toshiba Parotech 2) were mixed, kneaded, and pelletized in the same manner as in Example 1, except for K. The obtained pellets were injection molded to form test pieces for evaluating sliding performance, and the sliding performance was measured. The measurement results are shown in Table 1, and it was confirmed that the wear characteristics were poor.

Examples 5-6. Comparative Example 3 Carbon fiber as the fibrous reinforcing material in Example 1 was replaced with potassium titanate fiber "Teinumo D" (Otsuka Pharmaceutical Products), a combination of carbon fiber and potassium titanate fiber (1:1), or glass fiber (O8 -03-MA497, a product of Asahi Fiberglass Co., Ltd.) was mixed in the same manner as in Example 1.
The mixture was kneaded and pelletized. The obtained pellets were injection molded to form test pieces for evaluating sliding performance, and the sliding performance was measured. The measurement results are shown in Table 2.

Examples 7-8. Comparative Example 4 Example 1 of another company in which the contents of PTFE resin and molybdenum disulfide in Example 1 were changed to the amounts shown in Table 2.
The mixture was mixed and kneaded in the same manner as above to form pellets. The obtained pellets were injection molded to form test pieces for evaluating sliding performance.
Its sliding performance was measured. The measurement results are shown in Table 2.

Comparative Example 4 does not damage the mating member, but it cannot be recognized that the wear resistance and limit pv value are inferior.

Claims (1)

[Claims] 1. y't! I) Phenylene sulfide resin 30-7
0% by weight 1 polytetrafluoroethylene resin powder 5-15
Heavy! Person #, binarized molybdenum 1 to 5 layers? A polyphenylene sulfide resin composition containing 10 to 25% by weight of an inorganic filler having cleavability and 10 to 25% by weight of a complex reinforcing material. 2. The polyphenylene sulfide resin composition according to claim 1, wherein the cleavable inorganic filler comprises at least one of talc, mica, clay, and graphite. (5) The polyphenylene sulfide resin composition according to claim 1, wherein the fibrous reinforcing material is carbon*, fiber, potassium titanate fiber, or a combination thereof.