JP2001323115A - Resin composition for sliding member, and sliding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for sliding members which reduces the influence of the surface roughness of a mating material, exhibits an improved abrasion resistance, prevents the mating material from being damaged, and suppresses the increase in coefficient of friction and to provide a sliding member prepared from the same. SOLUTION: This resin composition is prepared by compounding a high-mol.- wt. polyethylene having a viscosity average mol.wt. of 400,000-900,000 with 3-30 wt.% particulate inorganic filler having an average particle size of 10-30 μm and 5-15 wt.% tetrafluoroethylene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition for a sliding member and a sliding member formed by molding the resin composition.

[0002]

2. Description of the Related Art Many sliding members such as synthetic resin bearings are used in sliding parts of various industrial and office equipment. As the sliding member, an oil-impregnated resin sliding member in which a synthetic resin contains a lubricating oil or a sliding member in which a synthetic resin contains a solid lubricant is used. While these sliding members have advantages such as low friction, light weight and low cost, they have a problem that wear resistance is greatly affected by the surface roughness of the mating material.
That is, when the surface roughness of the mating member increases, the wear resistance deteriorates. In general, in a synthetic resin sliding member, it is necessary to suppress the surface roughness of the mating material to 1.5 μmRmax or less, although it depends on the sliding form and sliding conditions.

[0003]

However, depending on the use of the sliding member, for example, the use of a structural member that has been subjected to a surface treatment such as metal plating as a direct mating member, the mating member may have a large surface roughness. May be unionized. In such a case, a method is employed in which a reinforcing material such as glass fiber or carbon fiber is blended to increase the surface hardness of the sliding member made of synthetic resin and to improve the wear resistance of the sliding member. In addition, there is a problem that the friction coefficient is increased or the mating material is damaged.

The present invention has been made in view of the above circumstances, and has as its object to reduce the influence of the surface roughness of a mating material, improve wear resistance and prevent damage to the mating material, An object of the present invention is to provide a resin composition for a sliding member and a sliding member that suppress an increase in friction coefficient.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, using a high molecular weight polyethylene having a specific molecular weight as a base resin,
A sliding member obtained from a resin composition in which a specific amount of an inorganic filler having a specific average particle size and a specific amount of tetrafluoroethylene resin are blended into the high-molecular-weight polyethylene is excellent even when the mating material has a large surface roughness. It has been found that the friction and wear characteristics can be exhibited. The present invention has been completed based on such findings, and the gist is as follows.

The first gist of the present invention is that a high-molecular-weight polyethylene having a viscosity-average molecular weight of 400,000 to 900,000 and a particulate inorganic filler having an average particle size of 10 to 30 μm are contained in a quantity of 3 to 3 particles.
0% by weight and 5 to 15% by weight of a tetrafluoroethylene resin are contained in the resin composition for a sliding member.

[0007] A second aspect of the present invention resides in a sliding member formed by molding the resin composition for a sliding member.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polyethylene used as a base resin in the present invention has a viscosity average molecular weight of 4
0000-900,000 high molecular weight polyethylene is used. If the viscosity average molecular weight is less than 400,000, the mechanical strength of the sliding member is insufficient, and it is difficult to obtain good sliding characteristics. On the other hand, when the viscosity average molecular weight exceeds 900,000, molding becomes difficult, and it becomes difficult to obtain a good molded product.

The viscosity average molecular weight is 400,000 to 90.
The high-molecular-weight polyethylene having a molecular weight of 0000 only needs to have the viscosity-average molecular weight in the above-mentioned range as the whole polyethylene, and may be composed of polyethylene components having a plurality of different viscosity-average molecular weights. For example, polyethylene composed of an ultra-high molecular weight polyethylene component having a viscosity average molecular weight of 1,000,000 or more and a low molecular weight polyethylene component having a viscosity average molecular weight of 300,000 or less may be used.

The particulate inorganic filler improves the wear resistance of the high molecular weight polyethylene as the base resin. The particulate inorganic filler includes carbonized phenol resin,
Phosphates and the like. These granular inorganic fillers have an average particle size of 10 to 30 μm. If the average particle size is less than 10 μm, desired wear resistance cannot be obtained, and if the average particle size exceeds 30 μm, there is a possibility that the mating material may be damaged.

[0011] The carbonized phenolic resin is prepared by mixing a granular phenol-formaldehyde resin in an inert atmosphere at 400 to 22%.
Carbonized by high-temperature sintering at 00 ° C., for example, “Bellepearl C-800 (trade name)” manufactured by Kanebo Co., Ltd.
"Bellpearl C-2000 (trade name)" is exemplified.

Examples of the phosphate include metal salts such as orthophosphoric acid, pyrophosphoric acid, phosphorous acid, and metaphosphoric acid, and mixtures thereof. Among these, alkali metal and alkaline earth metal secondary phosphates, tertiary phosphates and pyrophosphates are preferred, and lithium and calcium secondary phosphates, tertiary phosphates and pyrophosphates are particularly preferred. . Specifically, trilithium phosphate (Li ₃ P
O ₄ ), lithium hydrogen phosphate (Li ₂ HPO ₃ ), lithium pyrophosphate (Li ₄ P ₂ O ₇ ), tricalcium phosphate (Ca ₃ (PO ₄ ) ₂ ), calcium hydrogen phosphate (C
aHPO ₄ (· 2H ₂ O)) and calcium pyrophosphate (Ca ₂ P ₂ O ₇ ) are exemplified.

The amount of the particulate inorganic filler is 3 to 30% by weight, preferably 5 to 20% by weight, and more preferably 8% by weight.
１５15% by weight. If the amount is less than 3% by weight, the desired wear resistance cannot be obtained, and if the amount exceeds 30% by weight, the friction coefficient increases and the mating material may be damaged.

In the present invention, in addition to the above-mentioned particulate inorganic filler, an ethylene tetrafluoride resin is blended in order to suppress an increase in the coefficient of friction and maintain a low coefficient of friction. Lubricating powder is preferable as the tetrafluoroethylene resin, and specifically, “TLP-10” manufactured by DuPont-Mitsui Fluorochemicals Co., Ltd.
(Trade name) "," Lubron L-5 "manufactured by Daikin Industries, Ltd.
(Product name) ".

The blending amount of the tetrafluoroethylene resin is 5 to 15
%, Preferably 8 to 12% by weight. The amount is 5
When the amount is less than 15% by weight, it is difficult to keep the friction coefficient low, and when the amount exceeds 15% by weight, the mechanical strength of the sliding member decreases and the wear resistance deteriorates.

In order to mold the resin composition for a sliding member having the above-mentioned component composition, the viscosity average molecular weight is 400,000.
~ 900000 high molecular weight polyethylene, average particle size 10
３０30 μm of the particulate inorganic filler and the tetrafluoroethylene resin are respectively weighed and mixed by a mixer such as a Henschel mixer, a super mixer, a ball mill, a tumbler mixer, etc. to obtain a mixture, and the mixture is injection-molded or extruded. Or a mixture is melted and kneaded with an extruder, formed into a string-shaped molded product, and then cut to produce a pellet, which is then molded using an injection molding machine or an extruder as a molding raw material. A method is adopted.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, the sliding characteristics of the sliding members were evaluated by the following test methods (1) and (2).

Pin-on-disk test (1): The friction coefficient and the wear amount were measured under the conditions shown in Table 1. For the coefficient of friction, the coefficient of friction at the time of stability was shown, and for the amount of wear, the amount of dimensional change of the pin test piece (sliding member) after the test was shown.

[0019]

[Table 1] Sliding speed 0.67m / sec Load 400g Sliding distance 200km Lubrication No lubrication Counterpart material Galvanized steel sheet (Surface roughness 6μmRma
x)

Pin-on-disk test (2): The friction coefficient and the amount of wear were measured under the conditions shown in Table 2. For the coefficient of friction, the coefficient of friction at the time of stability was shown, and for the amount of wear, the amount of dimensional change of the pin test piece (sliding member) after the test was shown.

[0021]

[Table 2] Sliding speed 0.67m / sec Load 400g Sliding distance 200km Lubrication No lubrication Counterpart material Stainless steel plate (Surface roughness 1μmRma
x)

Example 1 The viscosity average molecular weight was 50,000.
15 weight% of carbonized phenol resin ("Bellpearl C800 (trade name)" manufactured by Kanebo Co., Ltd.) and high molecular weight polyethylene having an average particle size of 20 [mu] m and tetrafluoroethylene resin ("Rublon L-5 (trade name) manufactured by Daikin Industries, Ltd.) ) ") 10% by weight and mixed with a Henschel mixer, 35mmφ
Pellets were obtained by melt-kneading with a twin screw extruder. Then, using an injection molding machine (SG-50, manufactured by Sumitomo Heavy Industries, Ltd.), a pin test piece (sliding member) having a spherical surface with a diameter of 8 mm, a length of 7 mm, and a sliding surface of 10 mm in radius of curvature was obtained from the pellet. After molding, the sliding characteristics were evaluated. Table 3 shows the results.

<Examples 2 to 5, Comparative Examples 1 to 3>
In Example 2, except that the composition was changed as shown in Tables 3 and 4, the diameter was 8 mm and the length was 7 m in the same manner as in Example 1.
m, a pin test piece (sliding member) whose sliding surface was a spherical surface having a radius of curvature of 10 mm was formed. In the table, the phosphate has an average particle size of 2
0 μm of calcium pyrophosphate and low molecular weight polyethylene represent polyethylene having a viscosity average molecular weight of 50,000. Tables 3 and 4 show the component compositions and sliding characteristics. (Below)

[0024]

[Table 3] (Below)

[0025]

[Table 4]

From the above test results, all the sliding members formed by molding the resin composition of the present invention showed no damage on the surface of the mating member after the test, and showed good friction and wear characteristics.
On the other hand, the sliding members formed by molding the resin composition of Comparative Example all had a large amount of wear, and particularly the sliding member of Comparative Example 2 had an extremely large amount of wear. The sliding members of Comparative Example 1 and Comparative Example 3 had a coefficient of friction of 0.3 in Test (2).
In the case of the test (2) of Comparative Example 1, slight damage was observed on the surface of the mating material.

[0027]

According to the present invention described above, the influence of the surface roughness of the mating material can be reduced, the wear resistance is improved, the mating material is prevented from being damaged, and the increase in the friction coefficient is suppressed. A resin composition for a sliding member and a sliding member are provided.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C10M 125/02 C10M 125/02 125/24 125/24 169/04 169/04 F16C 33/20 F16C 33/20 A / / (C08L 23/06 (C08L 23/06 27:18) 27:18) C10N 10:02 C10N 10:02 10:04 10:04 20:04 20:04 20:06 20:06 Z 30:06 30 : 06 40:02 40:02 50:08 50:08 F term (reference) 3J011 SC02 SC05 SC12 SE10 4H104 AA04C AA20C CA02A CB12R CD02A EA03A EA08C FA01 FA02 LA03 PA01 QA21 4J002 BB041 BD152 DA036 DH046 DH056 GM05

Claims (3)

[Claims] (1) a viscosity average molecular weight of 400,000 to 9000;
00 high molecular weight polyethylene, average particle size 10-30μ
A resin composition for a sliding member, comprising 3 to 30% by weight of a particulate inorganic filler having a particle size of m and 5 to 15% by weight of an ethylene tetrafluoride resin. 2. The resin composition for a sliding member according to claim 1, wherein the particulate inorganic filler is a carbonized phenol resin and / or a phosphate. 3. A sliding member formed by molding the resin composition for a sliding member according to claim 1 or 2.