JPH1121408A - Tetrafluoroethylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition enabling to produce sliding members high in lubricity and improved in characteristics against frictions and wears by including specific carbon fibers, a powdery aromatic polyester, etc. SOLUTION: This tetrafluoroethylene resin composition comprises 40-94 wt.% of tetrafluoroethylene resin, 3-57 wt.% of carbon fibers having a Vickers hardness Hv of about 350 kgf/cm<2> or larger, and 3-57 wt.% of a powdery aromatic polyester (e.g. a liquid-crystalline wholly aromatic polyester resin comprising the polycondensation product of p-hydroxybenzoic acid, bisphenol and phthalic acid) having an average particle diameter of about 10-500 μm. The components are mixed with a Henschel mixer, etc. One part of the components may be replaced with a solid lubricant excluding the carbon fibers, such as natural graphite. The objective composition is useful for producing sliding members which slide on metals and are used under high pressure oil lubrication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a tetrafluoroethylene resin composition. More specifically, the present invention relates to a tetrafluoroethylene resin composition suitably used as a molding material for a sliding member used under high-pressure oil lubrication.

[0002]

2. Description of the Related Art Conventionally, a high-hardness carbon fiber is often used as a filler in a sliding member made of a tetrafluoroethylene resin which has improved sliding characteristics while maintaining strength under high-pressure oil lubrication. . However, high-hardness carbon fibers have a limit that, although the frictional force is reduced to a certain level, a decrease below that level cannot be expected.

[0003] When another solid lubricant is added to carbon fiber and used in combination, the effect of the high hardness of the carbon fiber is greater, and the effect of the other solid lubricant tends to be hardly observed. That is, if a small amount of carbon fiber is filled in the tetrafluoroethylene resin, the effect of other solid lubricants is hardly observed, and not only depends on the frictional force of the carbon fiber but also the amount of wear of the mating material is reduced. There is a tendency to increase.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tetrafluoroethylene resin composition obtained by adding a high-hardness carbon fiber to a tetrafluoroethylene resin as a filler. It is an object of the present invention to provide a sliding member used under lubrication, which can further enhance lubricity and further improve friction and wear characteristics.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
Tetrafluoroethylene resin 40-94 wt%, a Vickers hardness Hv of about 350 kgf / cm ² or more carbon fiber 3-57 wt% and an average particle size of about 10~500μm powdery aromatic polyester 3
5757% by weight of a tetrafluoroethylene resin composition. It can also be used as a tetrafluoroethylene resin composition in which a part of these three components is replaced by a solid lubricant other than carbon fiber.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A tetrafluoroethylene resin is used by adding a high-hardness carbon fiber and a powdery aromatic polyester. As a high hardness carbon fiber,
Vickers hardness Hv is about 350 Kgf / cm ² or more, preferably about 35
Those having 0 to 500 kgf / cm ² are used. When a material having a Vickers hardness of less than this value is used, the friction coefficient is low, but the wear resistance is poor. The reason for using an aromatic polyester is that, in order to maintain strength under a condition where a high pressure is applied, the filled high hardness carbon fiber generates a high frictional force, but is effective in reducing the frictional force. In the case of using low-hardness carbon fiber, it is no longer a prerequisite "sliding material under high pressure", and there is no point in using aromatic polyester. Examples of the powdered aromatic polyester include liquid crystalline wholly aromatic polyester resins (polycondensates of p-hydroxybenzoic acid, biphenol and phthalic acid) and the like, having an average particle size range of about 10 to 500 μm, preferably about 10 to 500 μm. Those having a size of 10 to 100 μm are used. The reason why the average particle size range is limited in this way is to avoid deterioration in physical properties due to the foreign matter effect of the filler. Actually, a commercially available product such as Sumitomo Chemical's Econol E101S can be used as it is.

[0007] These three components comprise 40 to 94% by weight, preferably 70 to 90% by weight of tetrafluoroethylene resin, 3 to 57% by weight, preferably 5 to 15% by weight of high-hardness carbon fiber, and powdery Aromatic polyester is 3 to 57% by weight, preferably 10 to
Used in a proportion of 20% by weight. If the proportion of the high-hardness carbon fiber is less than this, the strength under high pressure is insufficient, while if it is used in a proportion greater than this, the sealing property is reduced. On the other hand, if the proportion of the powdery aromatic polyester is smaller than this, the desired improvement in the friction and wear characteristics cannot be achieved, while if it is used in a proportion larger than this, the strength is reduced.

A part of these three components may be replaced with a solid lubricant other than carbon fiber, for example, carbon powder such as natural or artificial graphite, whisker fiber, talc powder, molybdenum disulfide and the like. Is 40 to 89% by weight of a tetrafluoroethylene resin, preferably 70 to 80% by weight, 3 to 52% by weight of a high-hardness carbon fiber, preferably 5 to 15% by weight, and 3 to 52% by weight of a powdery aromatic polyester. , Preferably 5 to 15% by weight, and another solid lubricant is used in a proportion of 5 to 54% by weight, preferably 5 to 15% by weight, respectively.

The composition is prepared by using a Henschel mixer or the like, and the mixed composition is charged into a predetermined molding die, and is subjected to a molding pressure of about 30 to 100 MPa using a compression molding machine. Preformed by holding for about 60-150 seconds. The preform is the melting point of the tetrafluoroethylene resin (327
℃) or more, generally about 350 to 390 ° C. for about 1 to 6 hours, and then cut into a desired shape.

[0010]

The sliding member obtained from the tetrafluoroethylene resin composition according to the present invention, when used under high-pressure oil lubrication, is constructed so that it slides with metal. The lubricating property is further improved than that obtained from the resin and the high hardness carbon fiber, and the friction and wear characteristics are further improved.

Therefore, the sliding member can be effectively used in applications requiring strength and low friction, particularly in applications requiring such conditions under high-pressure oil lubrication. .

[0012]

Next, the present invention will be described by way of examples.

Examples 1 and 2, Comparative Examples 1 to 5 Examples Comparative Examples Composition (parts by weight) 1 2 1 2 3 4 5 PTFE resin 80 80 80 90 90 90 85 Carbon fiber A 5 5 10 5 5 〃 B 5 10 Aromatic polyester 15 10 15 Natural graphite 5 5 Artificial graphite 10 Note) PTFE resin: Teflon 70-J, Mitsui Dupont Fluorochemical product Carbon fiber A: Kureha chemical product Kureka chop M-2007S Hv> 350Kgf / cm ² , average fiber length 70μm Carbon fiber B: Osaka Gas LXX-941 Hv <350Kgf / cm ² , Average fiber length 70μm Aromatic polyester: Sumitomo Chemical Econol E101S Average particle size 20μm Natural graphite: Chuetsu graphite product NC-350 Average particle size 40μm Artificial graphite : Nidec carbon product graphite KN average particle size 10μm

The above components are mixed in a Henschel mixer, and the obtained composition is preformed in a cylindrical shape by holding it at a molding pressure of 70 MPa for 2 minutes, and then baked at 370 ° C. for 3 hours. The sheet was processed into a thin sheet, and a test piece was prepared from the sheet. The coefficient of friction and wear of the test piece and the amount of wear were measured according to the following conditions. Measurement conditions Measurement of friction and wear coefficient Measurement of wear amount 9.8MPa 9.8MPa Speed 0.2m / sec 15cpm Time 5 hours 200,000 cycles Counter material ADC-12-T5 ADC-12-T5 Swing angle ± 720 ゜ Oil temperature 120 ° C 120 ℃

The results obtained are shown in the following table. Example Comparative Example Measurement item 1 2 1 2 3 4 5 [Friction and wear coefficient] Friction coefficient (-) 0.049 0.045 0.044 0.107 0.055 0.109 0.106 Wear coefficient 230 285 830 210 760 160 184 (× 10 ^-5 cmsec / (MPa・ M ・ time)] [Wear] Seal ring (mm) 0.26 0.27 0.80 0.63 0.93 0.31 0.46 Seal ring mating material (mm) 0 0 0 0 0 10 29

Claims (4)

[Claims] 1. A tetrafluoroethylene resin having a weight of 40 to 94%
%, The Vickers hardness Hv of about 350 kgf / cm ² or more carbon fibers 3
A tetrafluoroethylene resin composition comprising 57% by weight and 3 to 57% by weight of a powdery aromatic polyester having an average particle size of about 10 to 500 μm. 2. Tetrafluoroethylene resin 40-89 weight
%, The Vickers hardness Hv of about 350 kgf / cm ² or more carbon fibers 3
52% by weight, powdered aromatic polyester having an average particle size of about 10 to 500 μm 3 to 52% by weight and a solid lubricant other than carbon fiber 5
A tetrafluoroethylene resin composition comprising about 54% by weight. 3. A sliding member obtained from the tetrafluoroethylene resin composition according to claim 1 and used under high-pressure oil lubrication. 4. The sliding member used under high-pressure oil lubrication according to claim 3, wherein the sliding member is configured to slide with the metal.