JPH03292366A - Wear-resistant resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition excellent in wear resistance, prevention of friction, and mechanical properties by mixing a linear polyphenylene sulfide resin with a fluororesin and a spherical or fibrous filler. CONSTITUTION:50-85 pts.wt. linear polyphenylene sulfide resin (A) [e.g. Photoron KPS (trade name: Kureha Chemical Industries K.K.)] is mixed with 10-40 pts.wt. fluororesin (B) (e.g. a polytetrafluoroethylene) and 0-20 pts.wt. at least one filler (C) selected from the group consisting of spherical fillers (e.g. spherical silica particles) and fibrous fillers (e.g. highly heat-resistant aramide fibers or Teflon fibers) (the total of the components A, B, and C amounts to 100 pts.wt.). A resin composition is obtained which is extremely excellent in wear resistance, low friction properties, and mechanical properties. The composition can be used as a wear-resistant resin composition for a retainer for a dental spindle bearing wherein ultra-high speed rotation is required and a part related to a bearing which is used under severe conditions such as a piston ring wherein extremely high wear resistance is required.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a wear-resistant resin composition that can be used for sliding parts such as sliding bearings, cams, and bearing cages. -Relates to a wear-resistant resin composition made of a polyphenylene sulfide resin composition that has excellent wear properties, can be precisely molded by injection molding, and has well-balanced mechanical properties.

[Prior Art] A large amount of heat-resistant plastic materials, which can be injection molded, are used for sliding parts such as bearings in order to reduce weight and improve productivity. Polyphenylene sulfide resin is known as a thermoplastic resin with excellent heat resistance and chemical resistance. Compositions for sliding materials containing solid lubricants such as molybdenum and lubricating oils such as mineral oil and synthetic oil are well known.

[Problem to be solved by the invention]

However, when this composition is used for bearings, etc., the fibrous filler damages the mating material, resulting in rough wear behavior and often significantly accelerating wear on the plastic side.

In addition, the typical polyphenylene sulfide resin that has been used in the past is commercially available as Rydon (registered trademark) from Phillips Petroleum Company in the United States, and during the manufacturing process it is heat treated at high temperatures and By adding a cross-linking agent or a branching agent, a partially cross-linked or branched structure is introduced into a high molecular weight resin, so it is an inherently fragile resin (hereinafter referred to as branched PPS). (written as resin). In a composition obtained by filling such a branched PPS resin with poor toughness with a granular solid lubricant such as a fluororesin or molybdenum disulfide and other fillers, as the amount of solid lubricant added increases, Although the coefficient of friction increases, the mechanical properties conversely decrease. especially,
If the total amount of additives (i.e., the total amount of solid lubricants such as fluororesin and other fillers) exceeds 50% by weight, the composition will become extremely bulky and cannot be molded. Sexuality becomes extremely bad. Sliding parts manufactured from this composition are brittle and easily damaged, and even if they do not break, there is a problem in that part of the sliding part is missing during sliding, accelerating wear on the sliding surface.

Therefore, the present inventors solved the above problems and improved heat resistance and
As a result of repeated research to develop a polyphenylene sulfide resin that has excellent friction and wear characteristics, very little damage to the mating material, and is well-balanced in terms of mechanical strength, the molecular chain is increased to a high molecular weight during the polymerization stage. 30 to 85% by weight of this linear polyphenylene sulfide resin is used.
proposed a polyphenylene sulfide resin composition comprising 5 to 30% by weight of oxybenzoyl polyester and 10 to 60% by weight of fluororesin (Japanese Unexamined Patent Publication No. 175065/1983).

However, there was still room for improvement in terms of further improving wear resistance.

An object of the present invention is to provide a wear-resistant resin composition that has a linear polyphenylene sulfide resin as a matrix and has better friction and wear characteristics as well as mechanical and thermal properties.

[Means to solve the problem]

The present invention achieves the above object by combining 50 to 85% by weight of linear polyphenylene sulfide resin and 10 to 4% by weight of fluororesin.
This is a wear-resistant resin composition comprising 0% by weight and O to 20% by weight of at least one of a spherical filler and a fibrous filler.

Polytetrafluoroethylene can be used as the fluororesin.

Further, the spherical filler is spherical isotropic amorphous carbon particles 1
Spherical silica particles 9 can be made of at least one type of spherical silicone resin.

Furthermore, the fibrous filler can be at least one type of heat-resistant organic fiber or carbon fiber.

This will be explained in more detail below.

The linear polyphenylene sulfide resin (hereinafter referred to as linear PPS resin) used in the present invention has no crosslinking agent or branching agent added during polymerization, and is not heat treated at high temperatures after polymerization. It is a high polymer that does not contain crosslinks or branched structures in its molecules, and is disclosed in Japanese Patent Application Laid-open No. 61-733.
It is suitably produced by the method disclosed in Japanese Patent Publication No. 2, Japanese Unexamined Patent Publication No. 61-66720, and the like. Molten clay, which is a measure of molecular weight, is 500 poise or more when measured at 310°C and a shear rate of 200 (sec)-1, and can be obtained from Kureha Chemical Industry Co., Ltd. as "Photron (registered trademark) KPS. can.

Examples of the spherical filler used in the present invention include spherical isotropic amorphous carbon particles, spherical silica, spherical silicone resin, and spherical alumina, but in particular spherical isotropic amorphous carbon particles and spherical silica. is preferred.

Spherical isotropic amorphous carbon particles are produced using phenols, for example, as described in JP-A-58-17114 and JP-A-57.
Particles with an average particle size of 1 to 30 μm obtained by firing and carbonizing spherical cured phenol particles suitably produced by the method disclosed in Publication No. 177011 at a temperature of 500°C or higher in an inert atmosphere. From Kanebo Co., Ltd., “
It can be obtained as "Helpearl (registered trademark)-C". Since the particles are spherical fine particles, they have good fluidity and are dispersed extremely uniformly when blended into a resin, making them suitable for producing molded products with smooth surfaces.

Examples of the fibrous filler used in the present invention include highly heat-resistant aramid fibers such as Kevlar and Nomex manufactured by DuPont; Conex manufactured by Kijin ■, Teflon fibers, and carbon fibers.

The fluororesin used in the present invention is polytetrafluoroethylene (hereinafter referred to as PTFE).

Examples include tetrafluoroethylene-hexafluoropropylene copolymer, polytrichlorofluoroethylene, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, with PTFE being particularly preferred. Among the PTFEs, lubricant-edge PTFE powder with an average particle size of less than 20 μm is preferable; Teflon (registered trademark) TLP-10, TLP-10F-1 manufactured by DuPont; Lublon (registered trademark) L manufactured by Daikin Industries, Ltd. -2,L-5゜LD
-1; Fluon (registered trademark) Li2Q, L manufactured by IC1
i2O, L171, etc. are suitable.

The blending amount of the wear-resistant resin composition of the present invention is 50 to 85% by weight of linear PPS resin and 10 to 4% by weight of fluororesin.
0% by weight 2 Spherical filler material 0 to 20% by weight, fibrous filler 0 to 20% by weight )
is preferably 20 to 50% by weight of the total resin composition. In particular, the blending amount of fluororesin is 15 to 30% by weight2.
A composition containing 2 to 15% by weight of the spherical filler material and 2 to 15% by weight of the fibrous filler material is preferred because it has a good balance of friction/wear characteristics and mechanical properties.

If the total amount of fillers exceeds 50% by weight of the total resin composition, sufficient kneading will not be possible and a uniform composition will not be obtained, and the fluidity of the resin composition will be insufficient and molding will become difficult. , the mechanical strength of the composition also becomes extremely weak. On the other hand, if the total amount of fillers is less than 20% by weight of the entire resin composition, the friction and wear characteristics of the resin composition will not be sufficient.

In addition, even if the total amount of fillers is 20 to 50% by weight of the entire resin composition, if the amounts of both spherical fillers and fibrous fillers are less than 2% by weight, creep resistance, Not sufficient in terms of wear resistance.

On the other hand, 20% by weight each of spherical filler and fibrous filler.
Even if the amount is exceeded, no significant improvement in creep resistance or abrasion resistance is observed, but rather deterioration of moldability and surface properties occurs.

Furthermore, if the amount of fluororesin blended is less than 15% by weight, the effect of improving friction properties will be insufficient, while if it exceeds 30% by weight, melt-kneading will become difficult and it will be difficult to obtain a uniformly dispersed composition. become unable.

There are no particular limitations on the means of blending the raw material components used for producing the wear-resistant resin composition of the present invention. linear PPS resin,
Fluorine resin 1 Spherical filler and fibrous filler can be melt-kneaded separately, and these raw materials can be pre-mixed in a mixer such as a Henschel mixer or ribbon blender before being fed to the melt-mixer. You can also.

The melt mixer is a single-screw or two-wheel extruder.

Any equipment such as mixing rolls, pressure kneaders, pravender plastographs, etc. can be used.

The wear-resistant resin composition of the present invention may contain any amount of various additives depending on the intended use as long as the effects of the present invention are not diminished.

In that case, for example, alumina powder,
Silica powder, silicon carbide powder, silicon nitride powder, graphite powder, carbon lac powder.

- Examples include inorganic powders such as molybdenum sulfide powder. Examples of fibrous inorganic additives include glass fibers, potassium titanate fibers, silicon carbide fibers, and metal fibers such as aluminum, copper, and iron.

Furthermore, examples of organic additives include silicone resin powder, polyimide resin powder, and fluororesin fiber.

In addition, appropriate amounts of various stabilizers, fluidity improvers, surface modifiers, and coloring agents may be added as necessary for the purpose of improving processing stability, surface properties, toughness, etc., coloring, and preventing static electricity.

Antistatic agents, various resins, etc. may be added as appropriate.

[Function] In the wear-resistant resin composition of the present invention, a linear PPS resin is used as the polyphenylene sulfide resin constituting the matrix, and the functions of the fluororesin 1, spherical filler, fibrous filler, etc. Even if a large amount of abrasion filler is added, the mechanical strength of the composition does not decrease much, and a resin composition with extremely excellent wear resistance can be obtained. The reason is that linear PPS
The resin has branched PP terminal groups, which causes weaknesses in physical properties.
This is thought to be due to the fact that the amount is lower than that of S resin, and when compared at the same molecular weight, the entanglement between molecular chains increases, resulting in higher toughness.

This toughness of the matrix resin is an inseparable factor in adding a large amount of filler and in order to fully demonstrate its function.

〔Example〕

The present invention will be explained in detail below. Note that the present invention is not limited to these examples.

(Example 1, Comparative Example 1) Test pieces of compositions having the proportions shown in Table 1 below were prepared and thrust friction/wear tests were conducted.

Each composition contains Kureha Chemical Industry Co., Ltd. as a linear PPS resin.
``Fortron (registered trademark) KPS.

W-214J was used, and [Teflon (registered trademark) TLP-] manufactured by Mitsui DuPont Fluorochemical Co., Ltd. was used as the fluororesin.
Using 10J, spherical phenolic resin and its carbide (
Bell Pearl (registered trademark) R-800 and C-800J manufactured by Kanebo were used as the spherical amorphous carbon particles, rBFJ manufactured by Shinetsu Graphite Co. was used as the graphite, and Otsuka Chemical as the potassium titanate fiber. rT I SMO manufactured by Co., Ltd.
D 102" was used, and Teijin Co., Ltd. aramid cut fiber "HM-50J" was used as the aramid fiber.

Each composition was prepared by mixing the above-mentioned raw materials in the proportions shown in Table 1, and then preparing the compositions from Hague Buchler Instruments Co., Ltd. (HAAKE-
BUCHLERJNNSTRUMEN INC.
HEOCORD SYSTEM) 40, rotation speed 5ORPM.

The resulting composition was kneaded for 20 minutes at a temperature of 300''C.The resulting composition was compression molded at 300°C using a hot press to create disk-shaped test pieces with a diameter of 30mm and a thickness of 2lffl. A thrust friction/wear test was performed on the test piece using a thrust friction/wear tester (MODEL IIIE) manufactured by Orientik.The test shaft of the thrust friction/wear tester was made of bearing steel (SUJ-2).
) It was a cylindrical shape with an outer diameter of 25 m, an inner diameter of 20 mm, and a height of 15 mm, and was heat treated to a quenching and tempering hardness of HV700 or more, and then nickel plated.

The test conditions were a shaft thrust surface pressure of 10.0 kgf.
/d, sliding speed 2On+/min, temperature is room temperature,
The dynamic friction coefficient and wear coefficient were measured 5 hours after the start of the test. The measurement results are also listed in Table 1.

Table 1 Example kA, Comparative Examples 1-A, 1-C, and Example 1-
Comparing D and Comparative Example 1-B, the composition containing spherical amorphous carbon particles, which are spherical phenol resin carbide, as a filler is superior to the composition containing non-spherical graphite, which is a typical solid lubricant. A composition containing aramid fiber, which is a heat-resistant organic fiber, as a filler has a significantly lower coefficient of dynamic friction and wear coefficient than a composition containing potassium titanate fiber, which is an inorganic fibrous filler. The results show that the present invention provides a composition with excellent sliding properties.

Comparing Examples 1-B, 1-C, and 1-G with Comparative Example 1-E, it was found that the composition was good when the content of spherical amorphous carbon particles as a filler was up to 20% by weight. Although it exhibits sliding performance, at a higher content of 35% by weight, a significant decrease in sliding performance is observed. Furthermore, as shown in Examples 1-D and 1-E, compositions containing aramid fibers as fillers also have good sliding properties when the filler content is within the range of 20% by weight of the present invention. Is recognized.

Examples 1-A to 1-H and Comparative Examples 1-D and 1-E.

When compared with 1-F, a composition with extremely good sliding properties is obtained when the total amount of fillers is in the range of 20 to 50% by weight, but
When the total amount of fillers exceeds 50% by weight, the coefficient of dynamic wear particularly increases, and conversely, when the total amount of fillers exceeds 20% by weight, the coefficient of dynamic friction particularly increases, and in both cases, the sliding properties are significantly deteriorated.

(Example 2, Comparative Example 2) Test pieces of compositions having the proportions shown in Table 2 below were prepared, and a radial wear test was conducted.

The linear PPS resin, fluororesin bispherical phenolic resin carbide, graphite, potassium titanate fiber, and aramid fiber used as components of each composition were all the same as in Example 1 and Comparative Example 1.

Table-2 Twin-screw extruder manufactured by Ikegai Iron Works (MODEL PCM-
After kneading and extruding each component to make pellets using
Injection molded using IM-4749), outer diameter 16mm
, a test piece for measuring the coefficient of static friction with an inner diameter of 12-2 and a length of 10 mm (
(hereinafter referred to as test piece X), outer diameter 14 mm, inner diameter Lor
Im, a radial friction/wear test piece with a length of 10 mm (hereinafter referred to as
A test piece (referred to as test piece Y) was prepared.

The coefficient of static friction was measured using a slope-type static friction measuring device manufactured by NSK Ltd. for a 5U specimen with an outer diameter of 11.9 mm and a surface roughness of 0.2 Ra.
Measurements were made using a shaft made of S304 (surface hardness 56HRC) as a counterpart material. The shaft was inserted into the inner diameter surface of the test piece The coefficient of static friction was calculated as the tangent of the inclination angle of the shaft at the time. The results are also listed in Table 2.

On the other hand, the radial friction test was conducted using a radial friction and wear tester manufactured by NSK ■ with an outer diameter of 9.80 mm.

The above test piece Y was prepared using a 5US-420J2 shaft (surface hardness 58HRC) with a surface roughness of 0.2 Ra as a mating material.
It was carried out at room temperature using After inserting the shaft into the inner diameter surface of the test piece Y, a surface pressure of 300 g/C4 was applied, and the
The shaft was rotated at a rotational speed of 0 PPM, and the torque value generated on the test piece was measured using a load cell, and the dynamic friction coefficient μ was determined from the torque value. The coefficient of dynamic friction μ after 18 hours from the start of the measurement is also listed in Table 2.

The radial wear test was performed using a shaft with an outer diameter of 9.80m+
The test was carried out in exactly the same manner as the radial friction test described above, except that 5US-304 (surface hardness 56HRC) with a surface roughness of 0.2 Ra and a load surface pressure of 3 kgf/d was used.

Radial wear depth (μm) 18 hours after the start of measurement
) are also listed in Table 2.

The annular crushing test was performed using a push-pull stand manufactured by Kanen Seisakusho (
H-12 type) was used to measure the load when the test piece was crushed by applying a load to the side surface of the above-mentioned test piece Y at a deformation rate of 8 mm/grin. The results are also listed in Table 2.

Comparing Example 2-A and Comparative Examples 2-A and 2-B,
Compositions containing spherical amorphous carbon particles have a lower coefficient of static friction than compositions containing non-spherical graphite or potassium titanate fibers, which are solid lubricants.

Radial wear amount: 1 Excellent under annular crushing load. On the other hand, the composition of Example 2-B containing spherical amorphous carbon particles and aramid fibers exhibits extremely good friction and wear characteristics and annular crushing load.

The above results show that the composition of the present invention provides a composition with excellent sliding properties.

Comparing Examples 2-A and 2-B and Comparative Examples 2-C and 2-D, it was found that when the PTFE content exceeds 40% by weight, the strength of the matrix phase that forms the continuous phase in the composition decreases. This results in an increase in radial wear and a decrease in annular crushing load, and if the PTFE content is less than 10% by weight, a significant decrease in frictional properties occurs. The increase in the amount of radial wear seen in Comparative Example 2-D is considered to be due to the content of spherical phenolic resin carbide exceeding 20% by weight (see Comparative Example 1-E).

(Example 3. Comparative Example 3) A test piece was prepared from a composition having the proportions shown in Table 3 below.
A high speed wear test was conducted.

The linear PPS resin, fluororesin, spherical phenolic resin carbide, graphite, potassium titanate fiber, and aramid fiber used as components of each composition were all the same as in Example 1 and Comparative Example 1. Further, as the carbon fiber, carbon cut fiber (M-1077) manufactured by Kureha Chemical Industry (■) was used.

A composition was prepared by kneading each component in the same manner as in Example 1, and compression molding was performed using a heat press to form a 5-kilometer x 5-mm x 6-cm
A 5 mm plate-shaped test piece was prepared.

The wear test was carried out without lubrication at a sliding speed of 48.7 m/sec and a load of 224 g using a prototype Saban type wear tester manufactured by NSK ■. The mating material was a disc made of 5US420J2 (surface roughness: 0.I Ra, surface hardness: 45 HRC), 100-Φ x 15 cm wide, and the test piece was pressed against the circumferential surface of the mating material with a predetermined load. Wear characteristics are sliding time 3
The wear volume after time was measured and evaluated, and the results are also listed in Table 3.

Table 3 Comparing Examples 3-A and 3-D and Comparative Examples 3-A and 3-C, it is found that the composition containing spherical amorphous carbon particles of the present invention has similar non-spherical particles. It can be seen that the composition exhibits clearly superior wear resistance to certain graphite-containing compositions. Moreover, Example 3-B.

Comparing 3-C and Comparative Example 3-B, even though they are similar fiber-reinforced compositions, the composition containing aramid fibers and carbon fibers of the present invention is superior to the composition containing potassium titanate fibers. shows significantly better wear resistance than As the content of potassium titanate fiber increases, a significant decrease in abrasion resistance occurs as shown in Comparative Example 3-D.

Comparing Examples 3-E and 3-F with Comparative Examples 3-E and 3-F, it is found that the compositions using a combination of spherical amorphous carbon particles and aramid fibers or carbon fibers exemplified in the present invention have It can be seen that the composition exhibits much better wear resistance than a composition that uses a combination of non-spherical graphite, which is a solid lubricant, and potassium titanate fiber or aramid fiber.

As exemplified above, at least one of linear PPS resin, fluororesin, spherical filler represented by spherical amorphous carbon particles, and organic fibrous filler represented by aramid fiber and carbon fiber. The composition of the present invention is
It has been revealed that the composition has particularly excellent wear resistance and low friction properties.

〔Effect of the invention〕

As explained above, according to the present invention, a linear PPS resin with excellent toughness, mechanical properties, heat resistance, and chemical resistance is used as the matrix resin serving as the base of the composition, and a spherical inorganic resin is used as the wear-resistant component. Spherical fillers such as regular carbon particles and spherical silica particles, organic heat-resistant fibrous fillers typified by aramid fibers and carbon fibers, and a fluororesin as a low-friction material were blended. Therefore, it is possible to provide a composition with extremely excellent wear resistance, low friction, and mechanical properties.

The composition of the present invention can be used in bearing-related parts used under harsh conditions, such as retainers for dental spindle bearings that require ultra-high speed rotation, and piston rings that require extremely high wear resistance. It can be used as an abrasive resin composition.

Claims (4)

[Claims] (1) Linear polyphenylene sulfide resin 50-8
5% by weight, 10-40% by weight of fluororesin, and 0-20% by weight of at least one of a spherical filler and a fibrous filler.
A wear-resistant resin composition consisting of. (2) The wear-resistant resin composition according to claim (1), wherein the fluororesin is polytetrafluoroethylene. (3) A wear-resistant resin composition in which the spherical filler is at least one of spherical isotropic amorphous carbon particles, spherical silica particles, and spherical silicone resin. (4) A wear-resistant resin composition in which the fibrous filler is at least one type of heat-resistant organic fiber or carbon fiber.