JPH05132618A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition useful for automotive bearings, etc., excellent in mechanical strength, dimensional stability, heat resistance and self lubricity, composed of a polyphenylene sulfide resin, a glass fiber, a fluororesin and specific globular carbon fine power. CONSTITUTION:The objective resin composition comprises (A) 100 pts.wt. polyphenylene sulfide resin (B) 50-150 pts. wt. glass fiber, (C) 5-15 pts.wt. fluororesin such as polytetrafluoroethylene and (D) 10-50 pts.wt. globular carbon fine power obtained by heating a spherical bituminous material at 350-500 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition which is excellent in mechanical strength, dimensional stability, heat resistance and self-lubricating property and is suitable for bearings in the fields of automobiles and precision OA equipment. .. Specifically, it is made of a polyphenylene sulfide resin (hereinafter abbreviated as PPS) containing glass fibers, fluorine, and resin spherical carbon fine particles.

[0002]

2. Description of the Related Art PPS is a thermoplastic engineering plastic having excellent heat resistance and chemical resistance. However, since the resin alone is very brittle, it is reinforced with reinforcing fibers or the like.
The PPS thus obtained has improved mechanical strength, dimensional stability, and rigidity in addition to conventional performance, and is applied to the fields of automobiles, electric / electronic fields, and the like. However,
When they are used as the sliding member, only containing the reinforcing fiber is not suitable because the friction coefficient and the wear of the mating material increase. Therefore, as a composition to be put to practical use as a sliding member, 1) contains only a lubricant, 2) contains a lubricant and a reinforcing fiber or a filler, and 3) adds a lubricant, a reinforcing fiber and a filler. Is well known. Regarding 1), it is proposed in JP-A-61-225242 and JP-A-63-213561. Although this composition has excellent sliding properties, it cannot be denied that the composition has insufficient strength.

With respect to 2) as well, the digging action of the reinforcing fibers occurs and the essential sliding characteristics have not been improved. As the filler, addition of tetrafluoroethylene resin (hereinafter referred to as PTFE), inorganic filler, graphite and the like is disclosed. However, none of them satisfy the strength. Therefore, methods such as 3) are being studied. Japanese Patent Publication No. 61-37306 proposes a composition containing a specific amount of a resin, a reinforcing fiber and a solid lubricating component, but it is not practical because it uses an expensive filler or the compounding amount is not appropriate.

Further, Japanese Patent Laid-Open No. 62-34956 discloses that 100 parts by weight of PPS is filled with 40 to 200 parts by weight of a granular phenol-formaldehyde resin to improve tensile elongation and impact resistance with respect to the base resin. Has been done. Furthermore, it is possible to add glass fiber and Teflon powder. Further, in Japanese Patent Application Laid-Open No. 1-95158, spherical graphite or amorphous carbon is used as a total of 30
A system of 70% filling has been proposed, but in either case, since the compounding ratio is not appropriate, the fluidity and the compression strength decrease.

In any case, these compositions are not suitable for mechanical parts and the like which require sliding characteristics because strength and sliding characteristics are not well balanced.

On the other hand, attempts have been made to use a thermosetting resin as the sliding member, but this has drawbacks such as a long molding cycle and gradual shrinkage of the resin under high temperature conditions.

[0007]

The main object of the present invention is to provide a PPS base composition which is excellent in mechanical strength, dimensional stability, heat resistance, self-lubricity and the like.

[0008]

In order to overcome the above-mentioned drawbacks, the inventors of the present invention have the same compressive strength as phenolic materials and good sliding characteristics, and molding can be performed in the same manner as ordinary PPS molding. The resin composition which can be made was investigated earnestly. As a result, they have found that a composition containing PPS with glass fiber, a fluororesin, and spherical carbon fine particles in a specific compounding amount exhibits extremely excellent compressive strength and good sliding characteristics, and thus the present invention was completed. I arrived.

That is, in the present invention, 50 to 150 parts by weight of glass fiber and 5-1 to fluororesin are added to 100 parts by weight of PPS.
A resin composition comprising 5 parts by weight and 10 to 50 parts by weight of spherical carbon fine particles obtained by heating a bituminous product at 350 to 500 ° C.

What is PPS used here?

[0011]

It is a resin having a basic skeleton. In the present invention, PPS is not particularly limited, but PPS having a melt viscosity of about 3,000 to 10,000 poise is desirable because it has a good balance of physical properties and processability. When the melt viscosity increases, the fluidity decreases, but the compressive strength improves.
Those having a low melt viscosity are suitable for parts in which fluidity is more important than strength. As described above, PPS can be widely selected depending on the shape of the molded product, the use conditions, and the like. Further, copolymerization with other resins such as graft type, block type and random type is possible as long as it does not impair the physical properties of PPS. The glass fiber used in the present invention is not particularly limited, but in the case where high bending strength, bending elastic modulus and sliding characteristics are required, a fiber having a relatively small fiber diameter is desirable, and when increasing the compression strength. Fibers of relatively large diameter are suitable. However, the chopped strands having a diameter of 9 to 15 μm have a good balance of compressive strength and sliding characteristics. An aspect ratio of, for example, about 100 to 500 is well balanced in workability and physical properties. Binders can be used for these glass fibers. As the binder, a urethane type, an epoxy type, or a mixed type thereof is suitable for improving strength and heat resistance.

The amount of the fibers filled is preferably 50 to 150 parts by weight with respect to 100 parts by weight of PPS. When it is less than 50 parts, the strength is insufficient, and when it exceeds 150 parts, not only a small contribution to the improvement of the strength but also the fluidity is deteriorated.

The spherical carbon microparticles used in the present invention are spherical carbon microparticles obtained by making a bluish blue particle spherical and heating it at 350 to 500 ° C. and taking it out from the heating system.

Incidentally, a bituminous substance is a semi-solid substance having an adhesive property,
It is a solid hydrocarbon mixture. For example, it refers to natural asphalt, coal tar, coal tar pitch or heavy petroleum oil.

The spherical carbon fine particles thus obtained have a carbon content of 93.0 to 99.9%, and it is generally known that their internal structure has a lamellar structure composed of a condensed polycyclic aromatic compound. I have (Zimmer and
White; “Disclination struc
pure in carbonaceous Meso
phase and Graphite "Aeros
Pace Report (1976)). Such spherical carbon fine particles include, for example, “Rinoveth” (trademark) manufactured by Osaka Gas Co., Ltd., but a carbonized product or a graphitized product is particularly preferable.

In order to promote graphitization and improve sliding properties, these spherical carbon fine particles can be heat-treated again at 1000 ° C. or higher after heating.

These spherical carbon fine particles have an average particle size of 1 to 4
It is desirable to use the one having a thickness of 0 μm because the composition has a good balance of strength and flow characteristics. Further, the surface treatment of the spherical carbon fine particles may be appropriately carried out with an aminosilane, epoxysilane or titanate type treating agent.

The filling amount of the spherical carbon fine particles is PPS10.
It should be 10 to 50 parts by weight with respect to 0 parts by weight. Particularly, 10 to 30 parts by weight is desirable. If it is less than 10 parts by weight, the effect of adding it to the strength and sliding properties does not appear, and if it exceeds 50 parts by weight, the compressive strength and fluidity are deteriorated, which is not preferable. That is, excellent characteristics such as improvement in compressive strength can be seen only in the composition of the present invention.

The fluororesin used in the present invention is PTF.
E, chlorotrifluoroethylene resin, vinyl fluoride resin,
A vinylidene fluoride resin, a tetrafluoroethylene-pentafluoropropylene copolymer resin, or the like, which preferably acts as a solid lubricant, is preferable. Of these, PTFE or the like, which is generally known as a lubricant and is easily available, is suitable. Particle size is 10
Approximately 100 μm is easy to handle.

The content of fluororesin should be 5 to 15 parts by weight based on 100 parts by weight of PPS. This is because if it is less than 5 parts by weight, the sliding characteristics are not satisfied, and if it exceeds 15 parts by weight, the strength and heat resistance are lowered. More preferably 7-1
0 parts by weight is preferred.

Addition of optional additives to the composition for imparting rigidity, moldability and the like is not particularly limited. For example, carbon fiber, ceramic fiber, potassium titanate, silicon nitride, calcium carbonate, barium sulfate, calcium sulfate, talc, mica, kaolin,
Reinforcing fibers such as clay, glass beads, silicon beads, wollastonite, zinc stearate and carnauba wax, inorganic fillers or surface-treated products thereof. Further, resins and rubbers can be optionally added. Examples of the thermoplastic resin include polyethylene, ultra-high molecular weight polyethylene, polypropylene, butadiene rubber and the like, and engineering plastics such as polyamide, polycarbonate, polyacetal, polybutylene terephthalate, polyphenylene oxide, polyethylene terephthalate and polysulfone.

Examples of the thermosetting resin include phenol resin, epoxy resin, urethane resin, and copolymers thereof.

The method for producing this composition can be selected, for example, by mixing the components with a tumbler mixer, a ribbon blender, etc., melt-kneading with a twin-screw extruder, and pelletizing the molten resin by an arbitrary method.

[0025]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples.

The spherical carbon fine particles used in the examples are as follows.

Type Carbon content (%) A 99.0 (carbonized product) B 99.9 (graphitized product) Average particle size: about 20 μm

[0028]

Example 1 100 parts of PPS, glass fiber 80 having a diameter of 13 μm
20 parts by weight of A-type spherical carbon fine particles [Osaka Gas Co., Ltd. "Rinoveth" (trademark) carbonized product] and 6 parts by weight of PTFE were mixed with a tumbler mixer, and pellets were produced with a twin-screw extruder. A compression test piece and a sliding test piece * were molded using an injection molding machine [“Nestal Cycap 165/75” (model name) manufactured by Sumitomo Heavy Industries Ltd.). Compressive strength is A
Wear coefficient is 10kg based on STM D-695
f, the test speed was 20 cm / sec, and the test time was 24 hours.

*) Compression test piece: φ12.7 mm × 25.
4mm Sliding test piece: 70 x 70 x 2mm

[0030]

[Example 2] Spherical carbon fine particles of type B ("Linoves")
Instead of the graphitized product, a composition having the same composition as in Example 1 was prepared, processed, molded, and evaluated.

[0031]

Example 3 100 parts by weight of PPS, 110 parts by weight of glass fiber, 30 parts by weight of A type spherical carbon fine particles, PTFE1
0 parts by weight and 20 parts by weight of mica were processed in the same manner as in Example 1,
It was molded and evaluated.

[0032]

Comparative Example 1 65 parts by weight of glass fiber was added to 100 parts by weight of PPS, and processed and molded in the same manner as in Example 1 and evaluated.

[0033]

Comparative Example 2 To 100 parts by weight of PPS, 85 parts by weight of glass fiber and 20 parts by weight of A-type spherical carbon fine particles were added, processed and molded in the same manner as in Example 1 and evaluated.

[0034]

Comparative Example 3 100 parts by weight of PPS, 50 parts by weight of glass fiber and 20 parts by weight of PTFE were processed and molded in the same manner as in Example 1 and evaluated.

[0035]

Comparative Example 4 100 parts by weight of PPS and 100 parts of glass fiber
Parts by weight, A type spherical carbon fine particles 60 parts by weight, PTFE
10 parts by weight were processed and molded in the same manner as in Example 1 and evaluated. The results of Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 1.

In Comparative Examples 1 and 2, although the strength is good, the wear coefficient is remarkably large. In Comparative Example 3, the sliding property is excellent, but the compressive strength is reduced. In the system containing a large amount of spherical carbon fine particles as in Comparative Example 4, the strength was significantly reduced.

On the other hand, it is easily confirmed that the formulations of the present invention each have an excellent balance of strength and wear resistance.

[0038]

[0039]

The resin composition obtained according to the present invention has P
In addition to the original high mechanical strength of PS, it is possible to simultaneously provide high compressive strength and excellent sliding characteristics that could not be achieved by conventional PPS. In particular, the feature of this composition is that the compressive strength required by various structural materials is superior to other PPS resin compositions and shows the same value as a thermosetting resin. It is also ideal for bearings under high loads due to its excellent sliding characteristics. For example, a wide range of applications such as mechanical parts in the fields of automobiles, OA, communication equipment, electric and electronic fields, bearings of various motors, pumps, etc. have become possible.

Front page continuation (72) Inventor Masao Murayama, 30 Miyato, Nihonmatsu City, Fukushima Prefecture OK Inc. (72) Shinji Mori, 30, Miyato, Nihonmatsu City, Fukushima Prefecture OK Inc.

Claims (1)

[Claims] 1. A polyphenylene sulfide resin 100.
50 to 150 parts by weight of glass fiber, 5 to 15 parts by weight of fluororesin, and spheres of bitumen to 350 to 5 parts by weight.
A resin composition comprising 10 to 50 parts by weight of spherical carbon fine particles obtained by heating at 00 ° C.