JPH0971704A - Tetrafluoroethylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PTFE composition which is satisfactory in various physical properties that (i) the creep resistance is excellent, (ii) the abrasion resistance is excellent even in water or a highly humid atmosphere, (iii) it does not attack the mating member made of a soft metal, and (iii) it does not form a black powder when abraded. SOLUTION: This tetrafluoroethylene resin composition essentially consists of 100 pts.vol. tetrafluoroethylene, 3-40 pts.vol. powder of an organic resin (e.g. imido-containing synthetic resin) having a melt viscosity of 10<4> P or above at 350 deg.C and a shear rate of 10<2> sec<-1> and 3-40 pts.vol. inorganic filler being and/or talc having a pH of 6.5-7.5. The inorganic filler in the above composition can be replaced with 3-40 pts.vol. aromatic polyamide fiber having a fiber length of 1mm or below. Nonblack sliding parts comprising sintered moldings of the above composition and used in air, water or a highly humid atmosphere are also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tetrafluoroethylene resin composition that can be used as a sliding member such as a bearing and a seal, a method for molding the same, and a non-black sliding component that can be used in the atmosphere, water and humid atmosphere. .

[0002]

2. Description of the Related Art Tetrafluoroethylene resin (hereinafter referred to as PTFE
Is abbreviated. ) Is excellent in heat resistance and chemical resistance, and its coefficient of dynamic friction at the beginning of sliding is smaller than that of other resins, so it is widely used as a sliding member such as bearings and seal materials, but it has wear resistance. And since the creep resistance is not sufficient, various fillers are often added to improve this point.

As a filler to be added to PTFE, an inorganic filler such as glass fiber, carbon fiber, metal oxide, graphite, mica, talc, or an aromatic polyester resin, polyphenylene sulfide resin, polyamideimide resin, polyether is used. Organic fillers such as etherketone resin and thermoplastic polyimide are known.

Further, in Japanese Patent Laid-Open No. 32-32146,
A PTFE-based material containing PTFE, a main component, and graphite, carbon fiber or the like is disclosed.

The PTFE-based sliding material containing the above-mentioned filler forms a transfer film on the sliding surface of the mating material from the initial sliding stage under relatively dry conditions in the atmosphere, and has stable low friction A steady state with low wear is obtained.

[0006]

However, a sliding material made of a PTFE composition is a transfer film on a sliding partner material in a sliding condition in a humid atmosphere or water where water droplets adhere to the sliding surface. Therefore, there is a problem in that a steady state of low friction and low wear cannot be reached because the formation of a slab is not possible.

[0007] In particular, a sliding material used in water or in a high humidity atmosphere often has a mating material such as stainless steel or gun metal. However, a transfer film is hardly formed on the surface of the mating sliding material. .

As an example of the above-mentioned PTFE-based material, PT
The sliding material containing graphite and carbon fibers containing FE as a main component (Japanese Patent Laid-Open No. 32-32146) was far inferior in wear resistance in water or in a humid atmosphere to that in air.

In recent years, sliding members have been widely used for bearings and seal parts of household appliances, but these are all made of materials containing graphite or carbon fiber. For example,
Bearings for mixers, water purifiers, mixed faucets, packing seals for simple showers, plugs, valve seals, etc. Also,
Industrial applications include beverages such as juice and beer, other food manufacturing machines, bearings for conveyors, and seal parts.

In such a use environment that gets wet with water, P
When using bearings and seal parts made of TFE composition,
The sliding mating material may be violently attacked, wear resistance may not be fully exhibited, and problems such as water leakage and reduced system efficiency may occur, requiring frequent replacement of the sealing material, or the worst case. In some cases, black abrasion powder may be discharged and mixed into food or the like.

Generally, as a measure against the problem that black abrasion powder is discharged from a sliding member of food manufacturing equipment, a method of filling non-black minerals such as mica and talc has been studied.

According to this method, the soft counterpart material such as stainless steel is less damaged, but since the pH value of the mineral is 7.6 or more alkaline, the C--F bond in the PTFE molecule is broken during firing. Then, radicals are generated. In this case, of course, the mechanical strength such as strength and elongation of the molded product deteriorated, and sufficient wear resistance and creep resistance could not be obtained.

When the C--F bond is broken as described above, PTFE turns black, so that PTF containing a non-black mineral as a sliding component for underwater and humid atmospheres is used.
The E composition could not be commercialized as a sliding material.

It should be noted that mica, talc, etc. are treated with an acid,
Alternatively, when a synthetic mica in which the OH group portion was substituted with the F element was blended, the cleavage of the C—F bond by the alkaline component was suppressed, but the wear resistance in water or in a humid atmosphere could not be sufficiently supplemented.

As another non-black inorganic compound, a method for filling short fiber crystals called whiskers was also tested, and whiskers such as potassium titanate, sodium borate, calcium carbonate, zinc oxide and titanium oxide were tested and evaluated. However, none of them could satisfy the wear resistance in water or in a high humidity atmosphere. Since whiskers are carcinogenic, they cannot be used to seal beverages, food machinery, water supply and other water supply equipment.

As an organic filler, a polyether ether ketone resin (JP-A-63-118357), a polyether ketone (JP-A-4-149260), a polyether nitrile resin (JP-A-4-149259), a polyphenylene sulfide resin Attempts have also been made to blend PTFE with a polyetherimide resin, a polyamideimide resin, a polyether sulfone resin, or the like.

This method improved the creep resistance and did not damage the soft mating material, but the wear resistance of the composition in water or in a humid atmosphere was significantly inferior to that in the atmosphere. Furthermore, since the sintering condition of PTFE, which is the main component, is 360 to 380 ° C. for 10 hours, decomposition gas is generated from the organic filler during molding, and stable molding conditions cannot be established. Further, the specific gravity of the molded product was about 5% smaller than the theoretical value, the absolute value of mechanical strength was low, and the variation was large. When the filling amount of the organic filler was large, cracks occurred in the molded product.

Regarding the combined use of an organic filler and an inorganic filler, a thermoplastic polyimide as an organic filler,
A composition employing glass fiber, glass beads or graphite as an inorganic filler is described in JP-A-1-233150.

As described above, the combined use of the organic filler and the inorganic filler has the effect of improving the creep resistance, but when used in water or in a high humidity atmosphere, the glass fiber or glass beads violently act as a sliding partner material. The damaged, graphite-added composition produced black wear debris.

Further, as a method for suppressing the dropping of the filler from the sliding interface in water or in a humid atmosphere, polyphenylene sulfide resin or the like is blended with glass fiber, glass beads, etc. and dry mixed, and then baked in a powder state. It is also known to fill the product (Japanese Patent Laid-Open No. 52-
1974, JP-A-52-24252, JP-A-52-
22771, JP-A-55-24462).

However, even with the above method, the sliding property with good abrasion resistance in water cannot be obtained, and as described above, the polyphenylene sulfide resin decomposes during firing, so that satisfactory mechanical strength can be obtained. There wasn't.

Therefore, the object of the present invention is to solve the above-mentioned problems and to provide a PTFE composition used as a sliding material, which is excellent in creep resistance and in air.
Excellent wear resistance in water and high humidity atmosphere,
It is to obtain a PTFE composition satisfying all the properties of not attacking a soft metal counterpart and not generating black abrasion powder.

[0023]

In order to solve the above problems, in the present invention, tetrafluoroethylene resin 100 is used.
Shear rate 10 ² sec ^-1 , temperature 350 with respect to volume part
An essential component is 3 to 40 parts by volume of a powder of synthetic resin having a melt viscosity at 10 ° C. of 10 ⁴ poise or more, and 3 to 40 parts by volume of a mica or talc having a pH of 6.5 to 7.5, or an inorganic filler mixed with both. It was a PTFE composition.

Alternatively, with respect to 100 parts by volume of a tetrafluoroethylene resin, a synthetic resin powder having a shear rate of 10 ² sec ^-1 and a melt viscosity of 10 ⁴ poise or more at a temperature of 350 ° C.
This is a PTFE composition containing 40 parts by volume and 3 to 40 parts by volume of aromatic polyamide fiber having a fiber length of 1 mm or less.

As the above-mentioned synthetic resin powder, powders of at least one resin selected from the group consisting of thermoplastic polyimide resin, non-thermoplastic polyimide resin, polyetherimide resin and polyamideimide resin can be adopted.

Further, with respect to 100 parts by volume of the tetrafluoroethylene resin, 3 to 40 parts by volume of powder of the thermoplastic polyimide resin having a shear rate of 10 ² sec ^-1 and a melt viscosity of 10 ⁴ poise or more at a temperature of 350 ° C. and a pH value. With mica or talc of 6.5 to 7.5 or an inorganic filler mixed with both 3 to
Tetrafluoride, which is a molded product obtained by sintering and molding a tetrafluoroethylene resin composition containing 40 parts by volume as an essential component, in which the thermoplastic polyimide resin of the molded product is a thermoplastic polyimide resin having a crystallinity of 30% or more. It was a molded product of the ethylene resin composition.

Alternatively, with respect to 100 parts by volume of a tetrafluoroethylene resin, 3 to 40 parts by volume of a powder of a thermoplastic polyimide resin having a shear rate of 10 ² sec ⁻¹ and a melt viscosity at a temperature of 350 ° C. of 10 ⁴ poise or more, and fibers. A molded product obtained by sintering a tetrafluoroethylene resin composition containing 3 to 40 parts by volume of an aromatic polyamide fiber having a length of 1 mm or less as an essential component, and the thermoplastic polyimide resin of this molded product has a crystallinity of 3
A molded product of a tetrafluoroethylene resin composition, which is 0% or more of a thermoplastic polyimide resin, is obtained.

In the above molding method, the above-mentioned PTF is used.
A molding method of the PTFE composition in which the E composition is dry-mixed, heat-treated at 250 to 350 ° C., and then sintered and molded can be adopted.

Further, the above-mentioned molded article of the PTFE composition was adopted as a non-black type sliding part which is used in the atmosphere, water and humid atmosphere.

The PTFE composition of the present invention is bonded at a normal thermoforming temperature of PTFE (350 ° C. or higher) so that the synthetic resin melts so as to wrap the inorganic filler or the aromatic polyamide fiber, and then bonds. This bonding improves the creep resistance of the PTFE composition.

In addition, by blending a synthetic resin having a predetermined melt viscosity, the synthetic resin selectively flows and is a large unit which can be visually identified in ram continuous extrusion molding which is a general molding method of a PTFE composition. Phase separation does not occur. Furthermore, by applying a predetermined heat treatment before molding,
Generation of decomposition gas is suppressed during molding of the synthetic resin, and a molded product of good quality is obtained.

The mica or talc compounded in a predetermined amount in the composition, or the inorganic filler mixed with both, has a predetermined pH.
Since it is a value, the C—F bond in the PTFE molecule is not cleaved during thermoforming of the composition. Therefore, it does not impair the wear resistance, creep resistance and tensile strength of the composition,
The blackening phenomenon of PTFE due to the breaking of the bond does not occur.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION PTFE used in the present invention is a homopolymer of tetrafluoroethylene, and is
Since it softens at 90 ° C. but does not completely melt, it is a resin that can be compression-molded or extrusion-molded but not ordinary injection-molded. The PTFE used in the present invention is preferably in powder form because it can be uniformly mixed.

The commercially available PTFE usable in the present invention is listed below. That is, (Ikoku) made by Montedison Co .: Algoflon, made by DuPont: Teflon,
(UK) ICI: Fluon, Daikin Industries: Polyflon, Kitamura: Recycled Teflon KT-
For example, 300H and KT-300M.

The synthetic resin powder used as a PTFE filler in the present invention has a shear rate of 10 ² sec ^-1 and a temperature of 35.
A well-known heat-resistant resin having a melt viscosity at 0 ° C. of 10 ⁴ poise or more is used.

Here, the reason for limiting the lower limit of the melt viscosity under a predetermined condition is that the synthetic resin is homogeneously mixed with PTFE under the heat molding condition of a general PTFE, that is, a general PTFE. This is because, in the ram continuous extrusion molding, which is a method of molding the composition, the synthetic resin selectively flows so as not to cause phase separation in large units that can be visually discriminated. Further, with a synthetic resin having a melt viscosity less than the lower limit of the melt viscosity described above, it is not possible to improve the creep property of a molded article of the PTFE composition to an intended degree, and the mechanical strength of the molded article is significantly deteriorated. Become.

On the other hand, although it is not particularly necessary to limit the upper limit of the melt viscosity of the synthetic resin, the practical upper limit is 10.
It is about ¹² poise. That is, the synthetic resin powder used in the present invention has a shear rate of 10 ² sec ⁻¹ and a temperature of 350 ° C.
The melt viscosity of 10 ⁴ to 10 ¹² poise in the above can be used.

At a shear rate of 10 ² sec ^-1 ,
Resins such as polyphenylene sulfide resin having a melt viscosity at 0 ° C. of less than 10 ⁴ poise generate decomposition gas, and further, by ram extrusion molding, the polyphenylene sulfide resin selectively flows and is considerably large so that it can be visually identified. This is not preferable because phase separation of units occurs.

Examples of the organic synthetic resin satisfying the melt viscosity under the above-mentioned predetermined conditions are as follows. In addition, (
The abbreviations are shown in parentheses.

Polyether ether ketone resin (PEE
K), polyetherketone resin (PEK), polyetherketone etherketoneketone resin (PEKEKK),
Polyether sulfone resin (PES), thermoplastic polyimide resin (TPI), non-thermoplastic polyimide resin (P
I), polyetherimide resin (PEI), polyamideimide resin (PAI), I type liquid crystal polymer (LCP).

Further, as an example of a commercially available product, PEN
(Idemitsu Material Co., Ltd .: ID300RF), PEEK
(ICI: Victrex PEEK 450), P
EK (ICI: Victorex PEK), PEKE
KK (BASF Corporation: Ultra PEK A2000),
TPI (Mitsui Toatsu Chemicals: Aurum), PEI (GE
Plastics: Ultem 1000), PAI (Amoco: Torlon 4000TF), LCP (Sumitomo Chemical: Sumika Super E1000, E5000) Commercially available non-thermoplastic polyimide resins include the following. To be That is, it is P84 manufactured by Ranging Co., which is composed of the repeating unit of the following chemical formula 1.

[0042]

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Alternatively, UIP-S, UIP-R and the like manufactured by Ube Industries, Ltd., which are composed of repeating units of the following chemical formula 2, are used.

[0044]

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As the thermoplastic polyimide resin,
Examples include AURAM manufactured by Mitsui Toatsu Chemicals, Inc., which is composed of repeating units of the following chemical formula 3.

[0046]

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(In the formula, X represents a group selected from the group consisting of a hydrocarbon group having 1 to 10 carbon atoms, a hexafluorinated isopropylidene group, a carbonyl group, a thio group and a sulfone group; _{1 to} R ₄ represent hydrogen, a lower alkyl group, a lower alkoxy group, chlorine or bromine and may be the same or different, Y is an aliphatic group having 2 or more carbon atoms, a cycloaliphatic group, Represents a tetravalent group selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group in which aromatic groups are connected to each other directly or by a crosslinking member. Further, as the synthetic resin containing an imide group in the present invention, in addition to the above-mentioned non-thermoplastic polyimide resin and thermoplastic polyimide resin, polyetherimide resin and polyamideimide resin can be mentioned.

The average particle size of the synthetic resin powder used in the present invention is preferably 3 to 100 μm. Because
Outside of such a predetermined particle size range, it becomes difficult to uniformly disperse the resin powder in PTFE, and it becomes impossible to improve the wear resistance and creep resistance of the composition to which the resin powder is added. From this tendency, a particularly preferable average particle size is 1
0 to 50 μm.

The compounding amount of the synthetic resin powder used in the present invention is 3 to 40 parts by volume with respect to 100 parts by volume of PTFE. Because, if it is less than 3 parts by volume, the wear resistance and creep resistance of PTFE cannot be improved, and
This is because if it exceeds the volume, the formability is adversely affected.

Mica having a predetermined pH value used in the present invention is
Natural mica treated with acid to adjust its pH value to 6.5 to 7.5, or by replacing the OH group contained in natural mica with F element, the pH value is adjusted to 6.5 to 7.5. Adjusted synthetic mica can be used. Examples of commercially available synthetic mica include those manufactured by Nakako.

Regarding talc having a predetermined pH value used in the present invention, natural talc is acid-treated to have a pH value of 6.5.
Those adjusted to ~ 7.5 can be used.

The average particle size of such mica or talc is 3 to 100 μm, preferably 10 to 40 μm. Because, outside of such a predetermined particle size range, PTF
This is because it becomes difficult to uniformly disperse the resin powder in E, and it becomes impossible to improve the wear resistance and creep resistance of the composition to which the resin powder is added.

The compounding amount of mica or talc is PTFE
It is 3 to 40 parts by volume with respect to 100 parts by volume. This is because if it is less than 3 parts by volume, the abrasion resistance of PTFE cannot be improved, and if it exceeds 40 parts by volume, cracks are generated in the molded product.

The aromatic polyamide fiber used in the present invention is a fiber made of an aromatic polyamide resin which is also called aramid for abbreviating aromatic polyamide. Although the aromatic polyamide resin does not contain an aliphatic bond such as methylene in the main chain and is composed of an aromatic ring and an amide bond (-NHCO-), the aromatic polyamide fiber in the present invention has an amide bond of an aromatic ring. The position may be either para-type or meta-type.

Commercially available products of such aromatic polyamide fibers are exemplified by Akzo: Twaron, DuPont:
Kevlar, Teijin: Conex or Technora, or Unitika: Apierre.

The fiber length of the aromatic polyamide fiber used in the present invention is 1 mm or less. This is because long fibers having a length of 1 mm or more make it difficult to uniformly disperse the fibers in the PTFE, and the abrasion resistance and mechanical strength are significantly reduced. The shortest usable fiber length of the aromatic polyamide fiber is usually 0.1 mm. If the fiber length is less than 0.1 mm, it is difficult to sufficiently improve the abrasion resistance of PTFE. For this reason, the more preferable aromatic polyamide fiber has a fiber length of 0.15 to 0.7 mm.

PTF of such aromatic polyamide fiber
The compounding amount in the E composition is 3 to 40 parts by volume with respect to 100 parts by volume of PTFE. Because P is less than 3 parts by volume
This is because the abrasion resistance and creep resistance of TFE cannot be improved, and when it exceeds 40 parts by volume, it becomes difficult to uniformly disperse the aromatic polyamide fiber in PTFE and the moldability is also impaired.

Further, white pigments such as titanium oxide, zinc oxide and silicon oxide and other non-black pigments may be blended as long as the effects of the present invention are not impaired.
Furthermore, if it is a sliding member used for food related equipment,
Well-known antibacterial agents may be appropriately mixed.

It is preferable that the above-mentioned raw materials are dry-mixed by a tumbler mixer, a Henschel mixer, or the like, and then heat-treated at 250 to 350 ° C. and then sintered and molded, when mixing the predetermined amounts. The reason for limiting the heat treatment temperature is that at a temperature higher than 350 ° C., the fusion property of the powdery PTFE is deteriorated and sinter molding becomes difficult, and at a temperature lower than 250 ° C., the sintering temperature of the composition is low. This is because the generation of decomposition gas from the synthetic resin powder having a predetermined melt viscosity cannot be suppressed during shaping. From such a tendency, a more preferable heat treatment temperature is 280 to 310 ° C. The above heat treatment has the same effect even if it is performed on the synthetic resin before the dry mixing of the raw materials.

In the present invention, it is particularly preferable to perform heat treatment when thermoplastic polyimide is used as the synthetic resin. This is because, when the thermoplastic polyimide is heat-treated at the above-mentioned predetermined temperature, low-molecular weight impurities are gasified and molding stability is obtained, and since the crystallization temperature of this resin is around 280 ° C., the resin powder after the treatment is treated. Has been sufficiently crystallized.

When the plastic polyimide thus heat-treated is molded by using a ram extrusion molding machine, crystallization does not occur in the mold and good molding can be performed.

The method for molding the PTFE resin composition of the present invention is carried out by placing the composition, which is a powdery molding material, in a mold, and
After preforming by applying a pressure of 80 to 600 kgf / cm ² , a method of sintering the green compact taken out at 360 to 380 ° C., a method of compression molding while heating, a continuous molding method by a ram extruder, etc. Can be adopted.

[0063]

EXAMPLES The raw materials used in Examples 1 to 15 and Comparative Examples 1 to 18 are listed below. The abbreviations used in Tables 1 and 2 below are shown in [].

(1) Tetrafluoroethylene resin [PTFE] manufactured by Mitsui DuPont Fluorochemicals: 7-J (2) Thermoplastic polyimide resin [PI] Mitsui Toatsu Chemicals: Aurum 500 (3) Non-thermoplastic Polyimide resin [PI] Ranging Co., Ltd .: P84-HT (4) Polyetherimide resin [PEI] GE Plastics Co., Ltd .: Ultem 1000, (finely pulverized product, average particle size 25 μm) (5) Polyamideimide resin [PAI] Amoco: Torlon 4000TF (6) Polyetheretherketone resin [PEEK] ICI: Victrex PEEK-150P, (finely pulverized material, average particle size 20 μm) (7) Polyetherketone ketone ketone resin [PEEK] ICI: Ultra PEK A2000, (finely pulverized product, average particle size 30 μm) (8 ) Polyphenylene sulfide resin [PPS] made by Topren: T4AG (9) aromatic polyester [OBP] made by Sumitomo Chemical: Sumika Super 101S (10) glass fiber [GF] made by Asahi Fiber Glass: MF-KAC (11) Carbon fiber [CF] Kureha Chemical Co., Ltd .: M207S (12) Graphite [graphite], Nippon Graphite Co., Ltd .: ACP (13) Mica [Mica] (pH 6.5) Nakako Co., Ltd .: FM-20 (14) Mica [Mica] ] (PH 7.5, acid treated) Repco: M-325 (15) Mica [mica] (pH 8.0, acid treated) Repco: M-325 (16) Talc, (acid treated Made by Nippon Talc Co., Ltd .:
MS (17) Aromatic polyamide fiber [ARF] (para type,
Fiber length 0.25 mm cut fiber) AKZO: Towaron Micro 1088 (18) Aromatic polyamide fiber [ARF] (meta system,
2 denier, fiber length 0.6 mm cut fiber) Teijin Ltd .: Conex (19) Aromatic polyamide fiber [ARF] (meta system,
2 denier, fiber length 3 mm cut fiber) Teijin Ltd .: Conex [Examples 1 to 11, 13 and 14, Comparative Examples 2 to 9] Table 1
The raw materials were dry-mixed in a Henschel mixer in the mixing ratio shown in 3, and then heat-treated in an electric furnace at 300 ° C. for 4 hours. Then, use a ram extruder at 380 ° C and a pressure of 450 kg.
A bar material having a diameter of 30 mm was continuously molded under the condition of f / cm ² . The molded body was cut to form a test piece, which was subjected to the following test. (1) Compressive Creep Test A cubic test piece with one side of 12.7 mm was prepared according to ASTM-D621, and a load of 140 kgf / cm ² , 2
The rate of change in compression creep for 4 hours (%) was determined. (2) Abrasion test A ring-shaped test piece having an inner diameter of 17 mm, an outer diameter of 21 mm, and a height of 10 mm was prepared, and a thrust-type frictional wear tester was used in the air or water in the mating material SUS304 with a peripheral speed of 110 m / min.
The test was conducted under the conditions of a load of 4 kgf / cm ² and a test time of 50 hours, and the wear coefficient (× 10 ^-10 cm ³
/ Kgf · m) was determined. In addition, the degree of damage to the mating material was evaluated in two grades: good (◯) and bad (x). The above results and the color tone and moldability of the molded product are shown in Tables 1 to 3.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[Examples 12 and 15, Comparative Example 1, Comparative Example 1
0-18] The raw materials were dry-mixed in a Henschel mixer at the compounding ratios shown in Tables 2-4, and then 38 in a ram extruder.
Diameter 30 mm under conditions of 0 ° C and pressure of 450 kgf / cm ^2.
The bar material was continuously molded. The molded body was cut to form a test piece, which was subjected to the above-mentioned test. The results obtained are
It is also shown in Tables 2 to 4.

[Comparative Example 15] A synthetic resin powder having a composition ratio (volume ratio) of GF, PPS, and OBP of 2: 1: 2 was dry-mixed by a Henschel mixer, and then 1 by an electric furnace at 370 ° C. It was baked for a time. The filler made of synthetic resin powder and PTFE powder thus heat-treated are shown in Table 4.
After dry-mixing with a Henschel mixer at the compounding ratio shown in 380 ° C. with a ram extruder, pressure 450 kgf / cm.
A bar material having a diameter of 30 mm was continuously molded under the condition of ² . The molded body was cut to form a test piece, which was subjected to the above-mentioned test. The obtained results are also shown in Table 4.

As is clear from the results of Tables 1 to 4, Comparative Examples 1, 2 and 5 which contain the thermoplastic polyimide, but do not contain mica, talc or aromatic polyamide fiber having a predetermined fiber length, have a predetermined pH. , The creep resistance was improved, but the wear resistance in water was poor. Further, Comparative Examples 3, 4, and 17 in which the synthetic resin powder, mica, or aromatic polyamide fiber was excessively mixed, or Comparative Example 6 in which mica having a predetermined pH value or higher was mixed, were difficult to mold. Further, Comparative Example 18 in which the aromatic polyamide fiber exceeding the predetermined fiber length was blended was inferior in abrasion resistance in water.

Comparative Example 7 containing graphite instead of mica
Caused the molded body to turn black and damaged the sliding mating material in water. Further, Comparative Examples 8 and 9 containing PPS had poor moldability and poor creep resistance and abrasion resistance even when mica having a predetermined pH was added and heat treatment was further performed.

Comparative Example 11 containing carbon fiber is
Although it had excellent wear resistance (in the air and in water), it showed a black color due to inferior attack and creep resistance of the mating material. Comparative Example 12 to which graphite was added also had aggression of the mating material and was inferior in wear resistance in the atmosphere.

On the other hand, Examples 1 to 15 satisfying all the conditions were excellent in abrasion resistance and creep resistance without attacking the sliding mating material in either the air or water. . Note that it goes without saying that a sliding material made of a PTFE composition having such excellent sliding properties can be used as a sliding material in oil.

[0075]

[Effects] As described above, the present invention is based on tetrafluoroethylene resin, organic synthetic resin powder having a melt viscosity of 10 ⁴ poise or more under predetermined conditions, and mica having a pH of 6.5 to 7.5. Alternatively, talc or an inorganic filler mixed with both 3
An organic synthetic resin powder having a melt viscosity of 10 ⁴ poise or more under predetermined conditions with respect to a tetrafluoroethylene resin composition in which a predetermined amount of ˜40 parts by volume is blended, or a tetrafluoroethylene resin.
Since the tetrafluoroethylene resin composition was prepared by mixing a predetermined amount of 3 to 40 parts by volume of aromatic polyamide fiber having a fiber length of 1 mm or less, this product has excellent sliding characteristics inherent to PTFE and excellent creep resistance. In addition, it has excellent friction and wear characteristics, that is, it has excellent wear resistance in the air, in water, and in a humid atmosphere, does not attack the mating material of soft metal, and does not generate black wear powder. There is an advantage that the resulting tetrafluoroethylene resin composition is exhibited.

Claims (9)

[Claims] 1. A synthetic resin powder having a shear rate of 10 ² sec ⁻¹ and a melt viscosity at a temperature of 350 ° C. of 10 ⁴ poise or more and 3 to 40 parts by volume, and a pH of 6 with respect to 100 parts by volume of a tetrafluoroethylene resin. A tetrafluoroethylene resin composition comprising 5 to 7.5 mica or talc or 3 to 40 parts by volume of an inorganic filler mixed with both as an essential component. 2. A powder of synthetic resin having a shear rate of 10 ² sec ⁻¹ and a melt viscosity at a temperature of 350 ° C. of 10 ⁴ poise or more and 3 to 40 parts by volume with respect to 100 parts by volume of a tetrafluoroethylene resin and a fiber length. Aromatic polyamide fiber of 1 mm or less 3
A tetrafluoroethylene resin composition containing 40 parts by volume as an essential component. 3. The tetrafluoroethylene resin composition according to claim 1, wherein the synthetic resin powder is a resin powder containing an imide group. 4. The synthetic resin powder is a powder of one or more resins selected from the group consisting of thermoplastic polyimide resins, non-thermoplastic polyimide resins, polyetherimide resins and polyamideimide resins. The tetrafluoroethylene resin composition described in 1. 5. A thermoplastic polyimide resin powder having a shear rate of 10 ² sec ⁻¹ and a melt viscosity at a temperature of 350 ° C. of 10 ⁴ poise or more and 3 to 40 parts by volume with respect to 100 parts by volume of a tetrafluoroethylene resin, and a pH. Of 6.5 to 7.5 mica or talc or an inorganic filler mixed with both 3 to 40
A tetrafluoroethylene which is a molded product obtained by sintering and molding a tetrafluoroethylene resin composition having a volume part as an essential component, and the thermoplastic polyimide resin of this molded product is a thermoplastic polyimide resin having a crystallinity of 30% or more. Molded product of resin composition. 6. 3 to 40 parts by volume of a powder of a thermoplastic polyimide resin having a shear rate of 10 ² sec ⁻¹ and a melt viscosity at a temperature of 350 ° C. of 10 ⁴ poise or more relative to 100 parts by volume of a tetrafluoroethylene resin, and fibers. It is composed of a molded product obtained by sintering a tetrafluoroethylene resin composition containing 3 to 40 parts by volume of aromatic polyamide fiber having a length of 1 mm or less as an essential component, and the thermoplastic polyimide resin of this molded product has a crystallinity of 30%. A molded product of the above tetrafluoroethylene resin composition which is a thermoplastic polyimide resin. 7. A dry-mixed tetrafluoroethylene resin composition according to claim 1, 250
A method for molding a tetrafluoroethylene resin composition, which comprises heat-treating at ˜350 ° C. and then sintering and molding. 8. A non-black type sliding part for molding in air, in water and in a humid atmosphere, which is formed by molding the tetrafluoroethylene resin composition according to claim 1. Description: 9. A non-black-type sliding component which is formed of the molded product of the tetrafluoroethylene resin composition according to claim 5 or 6, and which is used in the atmosphere, water and humid atmosphere.