JP3078807B2 - Sliding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a port Li polyphenylene sulfide resin composition or we formed sliding member.

[0002]

2. Description of the Related Art Recently, the use of plastic sliding members has been expanding, and is expected to be a new material replacing conventional metal materials. The plastic member is excellent in self-lubricating property, which is a property desired for a sliding member, but has the disadvantage that it has a lower limit PV value and is inferior in mechanical strength such as rigidity as compared with a metal material. The “limit PV value” is a value represented by a product of a pressure (P) and a peripheral speed (V) when a normal frictional state cannot be maintained due to melting or burning of a material. Therefore, in order to apply plastic materials to sliding parts such as bearings, in addition to mechanical properties such as strength and rigidity, heat resistance, excellent shape and dimensional accuracy of molded products, etc., the dynamic friction coefficient is small. ,
A material having a high limit PV value, a small amount of wear, and a friction and wear characteristic of not damaging a mating material is required.

As a flame-retardant engineering plastic having high heat resistance and rigidity and excellent chemical resistance, polyphenylene sulfide (hereinafter abbreviated as “PPS”) resin is known. This PPS resin has also been studied as a resin for a sliding member, and is disclosed in JP-A-9-59514 and JP-A-9-31328, etc.
There has been proposed a PPS resin composition in which a resin is mixed with a polyethylene modified with an α, β-unsaturated carboxylic acid or an acid anhydride thereof.

[0004]

However, the resin composition containing the above-mentioned modified polyethylene has a problem that an adhering substance (mold deposit) is formed on a mold at the time of molding and a molded article is delaminated. .

An object of the present invention is to solve such a conventional problem, to provide a PPS resin composition which is excellent in friction and wear characteristics and which can reduce the occurrence of delamination of a mold deposit and a molded product during molding. An object of the present invention is to provide a sliding member using an object .

[0006]

According to the present invention , P
The PS-based resin composition comprises (A) a PPS resin of 50 to 94.5.
% By weight, (B) polyethylene modified with α, β-unsaturated carboxylic acid and / or α, β-unsaturated carboxylic anhydride (hereinafter referred to as “modified polyethylene”) 3 to 2
0% by weight, and 70 to 99% by weight of (C) α-olefin
And glycidyl esters of α, β-unsaturated carboxylic acids 1 to
An olefin-based copolymer obtained by copolymerizing 30% by weight (hereinafter referred to as "glycidyl group-containing olefin-based copolymer")
0.5 to 50% by weight).

[0007] The sliding member of the present invention is characterized by being formed from the top Symbol P PS resin composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the PPS resin (A) in the present invention, generally, PP
Various types of resins known as S resins can be used, and any of a linear structure and a crosslinked structure may be used. Specifically, a crystalline polymer containing a repeating unit represented by the following general formula as a main component can be given.

[0009]

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(Where Ar is a 1,4-phenylene group,
A 1,3-phenylene group or a 1,2-phenylene group is shown. In the present invention, those having the above-mentioned repeating unit as a main component, that is, those comprising only the above-mentioned repeating unit,
Alternatively, those containing 80 mol% or more, more preferably 90 mol% are desirable. When substantially all of the PPS resin does not consist of the above-mentioned repeating units, the remainder can be filled with a copolymerizable component composed of the following repeating units, for example.

[0011]

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(Here, R represents an alkyl group, an alkoxy group, a nitro group or a phenylene group.) In the present invention, a commercially available PPS resin may be used. Commercially available PPS resins include, for example, trade names “Topren” (manufactured by Topren Co., Ltd.), trade names “Lighton” (manufactured by Toray Industries, Inc.), and trade names “Fortron” (manufactured by Polyplastics Co., Ltd.). Can be

The modified polyethylene (B) in the present invention
Is a polyethylene modified with an α, β-unsaturated carboxylic acid and / or an α, β-unsaturated carboxylic acid anhydride.
A graft copolymer obtained by grafting an α, β-unsaturated carboxylic anhydride or a derivative thereof in the presence of a radical generator; and ethylene and an α, β-unsaturated carboxylic acid and / or α, β. -Binary copolymers with unsaturated carboxylic anhydrides.

The α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid anhydride include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methylmaleic acid, methylfumaric acid , Mesaconic acid,
Citraconic acid, glutaconic acid, monomethyl maleate,
Monoethyl maleate, monoethyl fumarate, methyl itaconate, methyl maleic anhydride, maleic anhydride, methyl maleic anhydride, citraconic anhydride, itaconic anhydride and the like are used, and these are used alone or in combination of two or more. These derivatives can also be used. Among these, maleic acid, acrylic acid, itaconic acid, maleic anhydride and itaconic anhydride are preferably used, and maleic anhydride is particularly preferably used.

As the polyethylene used for the modified polyethylene (B), low density, linear low density, medium density, high density polyethylene and the like can be used. The modified polyethylene (B) includes the above α, β-unsaturated carboxylic acid and α, β
Unsaturated monomers other than β-unsaturated carboxylic anhydrides, such as acrylates, methacrylates, styrene, acrylonitrile, etc., may be grafted or copolymerized.

Α, β- in the modified polyethylene (B)
The content of the unsaturated carboxylic acid and the α, β-unsaturated carboxylic anhydride is based on 100 parts by weight of the polyethylene component.
It is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight.

As the modified polyethylene (B), a copolymer obtained by grafting maleic anhydride is particularly preferable.
The amount is preferably 0.05 to 8 parts by weight, more preferably 0.05 to 5 parts by weight, based on 0 parts by weight. Although the viscosity of the modified polyethylene (B) is not particularly limited, the MFR at 190 ° C. and a load of 2.16 kg is used.
(Melt flow rate) is preferably from 0.01 to 100 g / 10 min, more preferably from 0.1 to 50 g / 10 min.

The glycidyl group-containing olefin copolymer (C) in the present invention is a copolymer containing an α-olefin and a glycidyl ester of an α, β-unsaturated carboxylic acid. As the α-olefin, ethylene, propylene,
Butene-1 and the like can be mentioned, and particularly preferably, ethylene is used. The glycidyl ester of an α, β-unsaturated carboxylic acid may be any ester of an α, β-unsaturated carboxylic acid having a glycidyl group. As the α, β-unsaturated carboxylic acid, for example, the α, β-unsaturated carboxylic acids listed in the description of the modified polyethylene (B) can be used. Specific examples of glycidyl esters include esters of such unsaturated carboxylic acids and glycidyl alcohol. For example, a compound represented by the following general formula can be mentioned.

[0019]

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(Where R represents a hydrogen atom or a lower alkyl group.) Specific examples of the compound represented by the above general formula include glycidyl acrylate, glycidyl methacrylate, and glycidyl ethacrylate (glycidyl α-ethyl acrylate). And the like. Among these, glycidyl methacrylate is preferably used.

The content of the glycidyl ester of α, β-unsaturated carboxylic acid in the glycidyl group-containing olefin copolymer (C) is 1 to 30% by weight, preferably 3 to 20% by weight. If the content is small, the effect of the present invention of reducing the occurrence of delamination of the mold deposit and the molded product during molding cannot be sufficiently obtained, and if the content is large, the gel is not melt-kneaded with the PPS resin. This is not preferable because extrudation stability and moldability may decrease.

The glycidyl group-containing olefin copolymer (C) may be copolymerized with another unsaturated monomer as long as the object and effects of the present invention are not impaired. Examples of such other unsaturated monomers include vinyl ether, vinyl acetate, vinyl propionate, acrylates such as methyl acrylate, methacrylates such as methyl methacrylate, acrylonitrile, and styrene. The content of these other unsaturated monomers is preferably 40% by weight or less.

In the PPS resin composition of the present invention,
PPS resin (A) 50 to 94.5% by weight, preferably 6
5 to 90% by weight, modified polyethylene (B) 3 to 20% by weight, preferably 7 to 15% by weight, glycidyl group-containing olefin copolymer (C) 0.5 to 50% by weight, preferably 1 to 30% by weight % Is contained.

When the content of the modified polyethylene (B) is not less than the above-mentioned predetermined amount, the friction and wear characteristics can be sufficiently improved, and when the content is not more than the above-mentioned predetermined amount, the excellent properties of the PPS resin can be obtained. Does not impair heat resistance.

When the content of the glycidyl group-containing olefin copolymer (C) is small, the effect of the present invention of reducing the occurrence of delamination of a mold deposit and a molded product during molding cannot be sufficiently obtained. , If the content is high, PPS
Gelation occurs during melt-kneading with the resin, and extrusion stability, moldability, and the like may be reduced, which is not preferable.

In the resin composition of the present invention, glass fibers, potassium titanate fibers, metal fibers, ceramic fibers, calcium carbonate, calcium silicate, magnesium silicate, calcium sulfate, and the like, as long as the objects and effects of the present invention are not impaired. Barium sulfate, iron oxide, graphite, carbon black, mica, asbestos, ceramics, metal flakes,
Fillers such as glass beads and glass powder, inorganic flame retardants such as magnesium hydroxide, aluminum hydroxide and antimony trioxide, organic flame retardants such as halogen and phosphoric acid, UV inhibitors, lubricants, crystal nucleating agents and dispersants , A foaming agent, a crosslinking agent, a coloring agent, a plasticizer, an additive, and the like.

For the purpose of enhancing the sliding properties, polytetrafluoroethylene, ordinary polyethylene, polyolefin copolymer, polyoxybenzoyl, spherical phenol, polyimide, silicone compound, graphite, molybdenum disulfide, etc. are added. can do.

In particular, it is desirable to add a reinforcing fiber in order to increase heat resistance, mechanical strength, dimensional accuracy and critical PV value. As such reinforcing fibers, from the viewpoint of not adversely affecting the slidability, alkali metal titanate fibers such as potassium titanate fibers, aluminum borate fibers, magnesium borate fibers such as magnesium borate fibers, Carbon fibers, wollastonite, calcium silicate fibers such as zonotolite, silica fibers, zinc oxide fibers and the like and those provided with a tin oxide-antimony oxide-based coating or a carbon coating on the surface of these fibers are preferably used. 0.05 ~
Those having an average fiber length of 5 μm, an average fiber length of 5 to 100 μm, and an aspect ratio of 3 or more are preferred.

Among these fibers, it is particularly preferable to use potassium titanate fibers. The amount of these reinforcing fibers to be added is preferably 5 to 50% by weight, more preferably 10 to 40% by weight in the whole composition.

When these reinforcing fibers are used, those treated with a titanate-based coupling agent, a silane-based coupling agent, an organic compound having an oxazoline ring, or another surface treatment agent can also be suitably used. . Further, these surface treatment agents may be added to the resin composition.

The resin composition used in the present invention can be prepared, for example, as follows. That is, after each component is evenly mixed using a blender or the like,
The mixture can be melt-kneaded with an extruder or the like to obtain a target resin composition. The obtained resin composition may be directly molded into a desired shape by means such as injection molding, or may be once pelletized using a pelletizer or the like.

The sliding member of the present invention can be obtained by molding the above Bark fat composition injection molding, extrusion molding, into a desired shape by a molding method such as press molding. Examples of such sliding members include bushings, bearings, sleeves, slip cylinders, guide rails, carriages, switch parts, gears, cams, and the like.

The details of the reason why the sliding member of the present invention is excellent in friction and wear characteristics and can reduce the occurrence of delamination of a mold deposit and a molded product during molding are not clear, but the glycidyl group The glycidyl group in the containing olefin copolymer (C) specifically acts on the PPS resin (A) and further reacts with the modified polyethylene (B) to improve the compatibility between the matrix and the dispersed particles. Seem.

The sliding member of the present invention can reduce the occurrence of delamination of a mold deposit and a molded product during molding, and can be efficiently produced. In addition, since the occurrence of delamination in the molded product can be reduced, a sliding member having excellent friction and wear characteristics and good mechanical strength can be obtained.

[0035]

The present invention will be described below in more detail with reference to examples and comparative examples. The present invention is not limited by these examples.

Examples 1 to 4 and Comparative Examples 1 to 4 After mixing the components in the proportions shown in Table 1, the mixture was fed to a twin-screw extruder (TEX44, manufactured by Nippon Steel Works, Ltd.) to obtain a pellet composition. I got The obtained pellet-shaped composition was injection molded to prepare a test piece. The materials used in the examples and comparative examples shown in Table 1 are as follows. The blending ratios shown in Table 1 are expressed in weight%.・ Polyphenylene sulfide resin: manufactured by Toray Industries, Inc.
Product name "Ryton 2120-60" E-GMA: manufactured by Sumitomo Chemical Co., Ltd., product name "Bond First E", glycidyl group-containing olefin copolymer, MFR: 3 g / min, GMA (glycidyl methacrylate) content : 12% by weight, ρ = 0.94 g / c
m ³ , Mw = 200000, Mn = 35000 LDPE: manufactured by Mitsubishi Chemical Corporation, trade name “Evolu SP2”
040 ", Mw = 100000, Mn = 31000, M
w / Mn = 3.3, ρ = 0.920 g / cm ³ MAH-LDPE: manufactured by Japan Polyolefin Co., Ltd.
Trade name “Adtex L6100N”, MAH (maleic anhydride) graft-modified low density polyethylene, MAH content: about 0.1% by weight, MFR: 1 g / min, ρ = 0.9
2 g / cm ³ , Mw = 110000, Mn = 29000-Potassium titanate fiber: manufactured by Otsuka Chemical Co., Ltd., trade name "Tismo D", average fiber diameter 0.5 m, average fiber length 1
5 μm The obtained test specimen was subjected to a friction and wear test and the mold deposit was evaluated by the following method. Table 1 shows the evaluation results.

(Test method) Friction and wear test (A) (Suzuki-type thrust wear) A Suzuki-type wear tester (manufactured by Orientec Co., Ltd.) was used, and cylindrical carbon steel (S45C) was used as a mating material. A cylindrical sample was molded by injection molding, and the friction velocity V = 0.3 m / sec and the surface pressure P = 10 k in a non-lubricated state.
Continuous operation was performed at gf / cm ² , and a friction coefficient when the friction distance reached 10 km, a unit distance, and a wear amount per unit area (mm ³ / kgf · km) were determined.

-Friction and wear test (B) (Journal wear test) Using a bearing wear tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.), using SKS steel with a diameter of 6.5 mm as a shaft material, and injecting the bearing by injection molding. Formed, continuously operated at 1200 rpm, surface pressure P = 1.55 kgf / cm ² in the state of no lubrication, and the friction coefficient and the unit distance, the amount of wear per unit load when the friction distance reaches 72 km ( mm ³ / kg
f · km).

Mold Deposit A 15-ton injection molding machine (Minimat M2 manufactured by Sumitomo Heavy Industries, Ltd.) is used by using a mold deposit evaluation mold (projection area: 2.6 cm ² , 1-cavity) having a tear drop mold cavity.
6 / 15B). The mold surface and the molded product surface after 500 shot molding in a molding cycle of 20 seconds were observed with a magnifying glass and evaluated according to the following criteria. ：: There is no deposit or fogging in the cavity of the mold, and the surface of the molded product is a mirror surface. Δ: Clouding is observed in the cavity of the mold, but the surface of the molded product is a mirror surface. X: Deposits and fogging are observed in the mold cavity, and irregularities are observed on the surface of the molded product.

[0040]

[Table 1]

As is clear from the results shown in Table 1, the polyphenylene sulfide-based resin composition according to the present invention has good sliding properties and can reduce the occurrence of mold deposit during molding. In the delamination of the molded product, delamination was observed in Comparative Examples 1 to 4, whereas no delamination was observed in Examples 1 to 4.

Examples 5 to 6 and Comparative Examples 5 to 6 After mixing the components in the proportions shown in Table 2,
The mixture was fed to the twin-screw extruder used in 4 to obtain a pellet composition. The obtained pellet-shaped composition was injection molded to prepare a test piece. PPS (polyphenylene sulfide resin) and E used in each of Examples and Comparative Examples shown in Table 2
-GMA used was the same as that used in Examples 1-4, and HDPE and MAH-HDPE used below. The mixing ratios shown in Table 2 are expressed in% by weight.

HDPE: manufactured by Mitsui Chemicals, Inc., trade name “HIZEX 2100J”, high-density polyethylene, ρ = 0.
957 g / cm ³ , Mw = 100000, Mn = 110
MAH-HDPE: manufactured by Mitsui Chemicals, Inc., trade name “Admer HE040”, maleic acid-modified high-density polyethylene, M
AH content: about 0.1% by weight, MFR = 1.6 g / 10
Min, ρ = 0.949 g / cm ³ , Mw = 65000, M
The test pieces with n = 9000 obtained were evaluated in the same manner as in Examples 1 to 4, and the evaluation results are shown in Table 2.

[0044]

[Table 2]

As is clear from the results in Table 2, the polyphenylene sulfide-based resin composition according to the present invention has good sliding characteristics and can reduce the occurrence of mold deposit during molding. In the delamination of the molded product, delamination was observed in Comparative Examples 5 and 6, whereas no delamination was observed in Examples 5 and 6.

[0046]

[0047]

The sliding member of the present invention exhibits excellent friction and wear characteristics, and a sliding member capable of reducing the occurrence of delamination of mold deposit and moldings during molding.

The sliding member of the present invention is-out <br/> in reducing the occurrence of delamination of mold deposit and moldings during forming shape Runode, can be produced efficiently.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shusuke Tsutsumi 463 Kagasuno, Kawauchi-machi, Tokushima City, Tokushima Prefecture Inside the Tokushima Research Laboratory, Otsuka Chemical Co., Ltd. (56) References JP-A-5-239350 (JP, A) JP-A-6 −93180 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 81/00-81/02 C08L 23/00-23/08 C08L 23/26 C08K 7/00-7 / 04

Claims (3)

(57) [Claims] (1) 50 to 94.5% by weight of a polyphenylene sulfide resin; (B) α, β-unsaturated carboxylic acid and / or α, β-
3 to 20% by weight of a polyethylene modified with an unsaturated carboxylic anhydride and (C) 70 to 99% by weight of an α-olefin and 1 to 30% by weight of a glycidyl ester of an α, β-unsaturated carboxylic acid. Olefinic copolymer obtained from 0.5 to 50
Sliding member, characterized in that it is formed from a port Li polyphenylene sulfide-based resin composition containing a weight%. 2. The sliding member according to claim 1, further comprising a reinforcing fiber. 3. The sliding member according to claim 2 , wherein the reinforcing fibers are potassium titanate fibers.