JP2954638B2 - Synthetic resin composition for sliding members - Google Patents

Description

The present invention relates to a synthetic resin composition for a sliding member suitable for use in bearings, cams, gears, sliding plates, liner tubes for flexible shafts, guide members and the like. It is about things.

(Prior art) Synthetic resins generally used for sliding applications such as bearings have the purpose of improving sliding characteristics such as self-lubrication and wear resistance.
It is well known to blend polytetrafluoroethylene resin (hereinafter referred to as PTFE) and / or glass fiber, carbon fiber and the like for the purpose of improving mechanical properties such as strength. -227, JP-A-58-179262,
JP-A-61-190553, JP-A-61-162549, JP-A-62
No. 185747, JP-A-62-223262, JP-A-63-278968,
Various proposals have been made in JP-A-1-127306 and JP-A-1-259059.

The sliding members disclosed in these prior arts have improved sliding characteristics by blending a certain ratio of PTFE with a base resin, and have abrasion resistance by blending a certain ratio of glass fiber and carbon fiber. All of them improve mechanical properties, and can be used under dry wear conditions without supplying lubricating oil to the sliding surface.

(Problems to be Solved by the Invention) However, in a sliding member used under dry friction conditions, the ability of forming a lubricating film on a surface (sliding surface) of a mating material, for example, a shaft, may deteriorate the performance. It depends greatly.

However, in the sliding member disclosed in the related art described above, it is difficult to say that the formation of the lubricating film on the surface of the mating material is not always good, and as a result, the coefficient of friction at the time of restarting by intermittent operation is high, and the dynamic friction coefficient is low. The problem of instability arises.

Various attempts have been made to improve the wear resistance and mechanical properties of sliding members by blending glass fibers, carbon fibers, and the like. Requires special attention. When a large amount is blended for the purpose of improving the strength, etc., there is a defect that the mating material is damaged or a lubricating coating formed on the surface of the mating material is scraped off, and these defects lead to abrasive wear. Is generated.

The present invention has been made in order to solve the above-described problems, and provides a synthetic resin composition for a sliding member that has excellent forming ability of a lubricating film on the surface of a mating member, and has excellent sliding characteristics and mechanical properties. It is intended for.

(Means for Solving the Problems) In order to achieve the above object, the present invention employs the following technical means (configuration). That is, a) 3 to 40% by weight of a polytetrafluoroethylene resin, b) phosphate 0.5
~ 15% by weight, c) glass fiber, glass powder, carbon fiber,
Reinforcement filler selected from amorphous carbon powder 1-30% by weight
Are uniformly mixed with each other.

The synthetic resin used in the present invention may have the mechanical properties and chemical properties required for the sliding member, as long as it has abrasion resistance and self-lubricating properties. More preferred. Further, depending on the application, the material may have elasticity capable of absorbing vibration and the like.

Specifically, polyacetal resin, polyamide resin,
ABS resin, polyamide imide resin, polyimide resin, polyether imide resin, polyethylene resin, polypropylene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyarylate resin, polyphenylene sulfide resin, polyether sulfone resin, polyether ether ketone resin, It is selected from polycarbonate resin, polyetherester resin, polyurethane resin, epoxy resin, and phenol resin.

The PTFE compounded in the base resin as a main component contributes to the self-lubricating property and low friction property of the base resin, and as the PTFE suitable in the present invention, for example, a product name `` Mitsui DuPont Fluorochemical Co., Ltd. "Teflon 7J", "Teflon 7AJ", product name "LUBRON L-
2, "Rublon L-5", "Rublon LD-1", and the brand name "KTL-610" manufactured by Kitamura Corporation.

The compounding ratio of the PTFE is preferably 3 to 40% by weight, more preferably 10 to 25% by weight. If the amount is less than 3% by weight, no effect is exerted on the self-lubricating properties and low frictional properties of the base resin. If the amount exceeds 40% by weight, the moldability deteriorates and the mechanical strength decreases.

Phosphate does not show any lubricity per se, but is mixed with the synthetic resin, which is the main component, together with the above-mentioned PTFE, so that it can adhere to the surface of the mating material (sliding surface) during sliding.
It has the effect of promoting the formation of a lubricating coating of PTFE, increasing the retention of the coating on the mating material, and increasing the durability of the coating.

Phosphates include tertiary phosphates, secondary phosphates, pyrophosphates, phosphites, metaphosphates, and mixtures thereof, of metals such as alkali metals and alkaline earth metals. Among them, tertiary phosphate, second phosphate and pyrophosphate are preferred in terms of forming the above-mentioned lubricating coating.

Specifically, trilithium phosphate, dilithium hydrogen phosphate, lithium pyrophosphate, tricalcium phosphate, calcium hydrogenphosphate, calcium pyrophosphate, trimagnesium phosphate, magnesium hydrogenphosphate, magnesium pyrophosphate, triphosphate Barium, barium hydrogen phosphate and barium pyrophosphate are preferred.

The proportion of the phosphate is preferably 0.5 to 15% by weight, more preferably 3 to 10% by weight. If the compounding ratio is less than 0.5% by weight, the formation of a PTFE lubricating film on the surface of the mating material and the effect on the retention and durability of the film are not exerted. There is a disadvantage that the amount of the PTFE lubricating film formed is too large, and the sliding characteristics are rather deteriorated.

Glass fiber, glass powder, carbon fiber, and amorphous carbon powder as reinforcing fillers are mixed with synthetic resin as a main component to improve mechanical strength, especially as a sliding member, and to slide the sliding member. It plays the role of increasing the surface hardness of the surface and improving the wear resistance.

The compounding ratio of these reinforcing fillers is 1 to 30% by weight, especially 5
~ 20% by weight is preferred.

In general, a large amount of the reinforcing filler should be avoided for reasons such as damaging the mating material in sliding with the mating material and causing abrasive wear due to the presence of generated wear powder. In the above, the effect of the phosphate described above promotes the formation of a lubricating coating of PTFE on the surface of the mating material, and the retention and durability of the film are enhanced. As a result, a large amount of 30% by weight can be blended.

Glass fibers used as reinforcing fillers are glass fibers conventionally used in the art,
That is, wollastonite, potassium titanate whisker, and the like can be used in addition to amorphous silicate glass, borate glass, and the like.

As the carbon fiber, a carbon fiber starting from polyacrylonitrile, rayon, polyvinyl alcohol, phenol, pitch or the like is used.

These fibers have a diameter of 1-20 μm, especially 5-15 μm
Preferably, the length is 20 to 6000 μm, especially 50 to 300 μm.

As the glass powder, a powder made of the above-mentioned amorphous silicate glass, borate glass, or the like is used.

Coke powder, anthracite powder, and amorphous carbon powder
Powder obtained by heat-treating amorphous carbon powder such as carbon black powder or charcoal powder, or polymer compound powder such as phenol resin powder in an inert atmosphere at a temperature exceeding 550 ° C (“Bell Pearl” manufactured by Kanebo) Is used.

The particle size of these powders is 100 μm or less, especially 1 to 40 μm
Is used.

Although the synthetic resin composition for a sliding member of the present invention is composed of the above-described component compositions, in addition to these component compositions,
In order to further improve moldability, wear resistance, and load resistance,
For example, a solid lubricant such as molybdenum disulfide or graphite, a soft metal such as lead, or the like can be blended at a ratio of 5% by weight or less.

(Example) Hereinafter, an example of the present invention will be described.

<Examples 1 to 3 and Comparative Example 1> Polyamide resin (hereinafter referred to as PA: manufactured by Toray Industries, trade name "Nylon 66CM3001N") powder was mixed with PTFE (manufactured by Daikin Industries, trade name "Rublon L-5") powder. Glass fiber (hereafter GF), amorphous carbon powder (hereafter CP) or mixed powder obtained by mixing carbon fiber (hereafter CF) and phosphate powder is used as molding material, which is screw-in-line injection molding Depending on the machine, molding temperature 250-290
Molding was performed under the conditions of ° C. and an injection molding pressure of 700 kg / cm ² to obtain a square test piece having a thickness of 30 mm and a thickness of 5 mm.

<Examples 4 to 6 and Comparative Example 2> Polyphenylene sulfide resin (hereinafter referred to as PPS:
A mixed-in powder obtained by mixing the PTFE powder, GF, CF or CP and phosphate powder with powder (trade name “T-4” manufactured by Topren Co., Ltd.) is used as a molding material, and this is used as a screw-in-line type seed molding machine. The molding was performed under the conditions of a molding temperature of 270 to 300 ° C. and an injection molding pressure of 800 kg / cm ² to obtain a square test piece having a thickness of 30 mm and a thickness of 5 mm.

<Examples 7 and 8> Polycarbonate resin (hereinafter, referred to as PC: manufactured by Mitsubishi Gas Chemical Company, trade name “Iupilon S2000”) was mixed with powder of PTFE.
The mixed powder obtained by mixing the powder with GF or CP and the phosphate powder is used as a molding material, and is subjected to a screw-in-line type injection molding machine at a molding temperature of 250 to 300 ° C. and an injection molding pressure of 1000 kg / cm ² . Molded with 30 pieces
A square test specimen having a thickness of 5 mm and a thickness of 5 mm was obtained.

<Examples 9 and 10 and Comparative Example 3> The PTFE powder, CF or CP and a phosphate powder were mixed with a phenol resin (hereinafter referred to as PH: Showa Union Gosei Co., Ltd. product name "BRP-520") powder. The obtained mixed powder is used as a molding material, and this is molded at a molding temperature by a compression molding machine.
160 ° C., and molded under the conditions of molding pressure 200 kg / cm ^2, a piece is 30m
A rectangular test piece having a thickness of 5 mm and a thickness of 5 mm was obtained.

The results of a thrust test performed on the molded products obtained in the above Examples and Comparative Examples under the following conditions are shown in the table.

<Test conditions> Sliding speed: 20m / min Load: 10kg / cm ^2- phase Hand material: SUS304 (outer diameter 25.5mm, inner diameter 20.0mm) # 800 emery finish Lubrication: no lubrication Time: 24 hours Is PTFE, b is phosphate, and c is reinforcing filler. Further, the coefficient of friction indicates a fluctuation range after one hour from the start of the test.

From the test results described above, it can be seen that the synthetic resin composition of this example shows a stable low coefficient of friction throughout the test time and a very small value of the wear amount as compared with the comparative example. In Examples 1 to 10, it was observed that a lubricating coating of PTFE was firmly formed on the surface of the mating member after the test.

(Effect of the Invention) The synthetic resin composition for a sliding member of the present invention is excellent in the ability to form a lubricating film on the surface of a mating material, and is excellent in sliding properties and mechanical properties. As a result, the coefficient of friction at the time of restart is low, the coefficient of dynamic friction is stable, and the wear resistance is excellent regardless of the sliding speed.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 7/14 C08K 7/14 F16C 33/20 F16C 33/20 A // (C08L 101/00 27:18) (56) Reference Document JP-A-1-79259 (JP, A) JP-A-62-104871 (JP, A) JP-B-38-20715 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 27/18 C08L 101/00 C08K 3/32 C08K 3/04 C08K 3/40

Claims (3)

(57) [Claims] 1. Polyacetal resin, polyamide resin, AB
S resin, polyamide imide resin, polyimide resin, polyether imide resin, polyethylene resin, polypropylene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyarylate resin, polyphenylene sulfide resin, polyether sulfone resin, polyether ether ketone resin, A synthetic resin selected from a polycarbonate resin, a polyetherester resin, a polyurethane resin, an epoxy resin, and a phenol resin as a main component, wherein the synthetic resin includes: a) 3 to 40% by weight of a polytetrafluoroethylene resin, b) phosphoric acid 0.5 to 15% by weight of a salt, c) A synthetic resin composition for a sliding member, which is obtained by uniformly mixing 1 to 30% by weight of a reinforcing filler selected from glass fiber, glass powder, carbon fiber and amorphous carbon powder. 2. The synthetic resin composition for a sliding member according to claim 1, wherein the phosphate is a phosphate of an alkali metal or an alkaline earth metal. 3. The method according to claim 1, wherein the phosphate is trilithium phosphate, dilithium hydrogen phosphate, lithium pyrophosphate, tricalcium phosphate, calcium hydrogenphosphate, calcium pyrophosphate, trimagnesium phosphate, magnesium hydrogenphosphate.
At least one of magnesium pyrophosphate, tribarium phosphate, barium hydrogen phosphate, barium pyrophosphate
The synthetic resin composition for a sliding member according to claim 2, which is at least one kind.