JPH01223150A - Tetrafluoroethylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition excellent in creep and sealing resistance without impairing excellent abrasion characteristics unique to tetrafluoroethylene resin, by blending the tetrafluoroethylene resin with a specific thermoplastic polyimide resin and inorganic filler. CONSTITUTION:A composition obtained by blending (A) 100pts.wt. tetrafluoroethylene resin which is a homopolymer of tetrafluoroethylene, preferably powdery resin with (B) 3-50pts.wt. thermoplastic polyimide resin which is powder, having preferably <=50mum average particle diameter, prepared by cyclodehydrating a polyamic acid obtained by reacting an ether diamine expressed by formula I (X is direct bond, 1-10C hydrocarbon group, hexafluoroisopropylidene group, etc.; R1-R4 are H, lower alkyl, etc.) with one or more tetracarboxylic acid dinahydrides and expressed by formula II (Y is >=2C aliphatic, cycloaliphatic group, etc.) and (C) 3-30pts.wt. inorganic filler (e.g., glass fibers or glass beads).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to a tetrafluoroethylene resin composition for use in sliding parts.

[Conventional technology]

Tetrafluoroethylene resin (hereinafter abbreviated as PTFE) not only has excellent heat resistance and chemical resistance, but also has a low coefficient of friction and self-lubricating properties, making it suitable for use in sliding parts such as bearings and gears. It has been widely used in various fields as a typical engineering plastic for materials, pipes, valves, and other molded products, but its wear resistance is not always satisfactory, so it has been improved by adding various fillers. There have been many attempts to do so. Examples of the filler include inorganic fillers such as glass fiber powder, glass peas, carbon fiber, graphite, and molybdenum disulfide, and organic fillers such as aromatic polyester, polyimide, polyphenylene sulfide, and aromatic polyamide. , PTFE material has large deformation (creep) under load, and when used as a straight-cut product of high-performance seal rings, a certain amount of compressive stress is generated at the joint part when the gap in the sealing gap disappears during use. transform. If the seal ring is used again, the sealing performance will deteriorate due to the deformation of the abutment. Therefore, increasing the amount of filler or compounding it, and even PTFI! A number of measures have been taken to improve the creep property, such as by modifying the material itself, but even if these methods can improve the creep property, the mechanical strength may be reduced or the sliding properties may be poor, so it is not desirable. There is also a method to make a laminate or composite by injection molding a thermoplastic resin or thermosetting resin with low creep properties around a thin PTFH material, but this method is time-consuming and economically disadvantageous. be.

[Problem to be solved by the invention]

As described above, in conventional technology, even PTFE, which has excellent heat resistance and chemical resistance, undergoes large deformation (creep) under load and does not have sufficient performance as a seal ring.In order to improve this, various fillers have been used. If it is mixed in, it is undesirable because it reduces mechanical strength or sliding properties, and it is not easy to mold and is expensive, but it is satisfactory in all aspects such as creep resistance, mechanical strength, friction and wear characteristics, and sealing performance. There was a problem that nothing could be obtained, and the challenge was to solve this problem.

[Means to solve the problem]

In order to solve the above problems, this invention
100 parts by weight, - a group selected from the group consisting of a direct bond, a hydrocarbon group having 1 to 1 carbon atoms, a hexafluorinated isopropylidene group, a carbonyl group, a thio group, or a sulfone group; and R1 to R4 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, a monocyclic aromatic group, a fused polycyclic aromatic group, or a non-fused polycyclic group in which aromatic groups are interconnected directly or through a bridge member. A thermoplastic polyimide resin consisting of repeating units of the formula (representing a tetravalent group selected from the group consisting of aromatic groups) and 3 to 30 parts by weight of an inorganic filler as essential components. This method employs a method of preparing an ethylene-containing resin composition.

First, PTFE in this invention is a homopolymer of tetrafluoroethylene (tetrafluoroethylene), and includes Alboflon (Montegison Co., Ltd., Italy), Teflon (manufactured by Depon Co., Ltd. in the United States), and Fluon (made by I.C.I. in the United Kingdom). (manufactured by Daikin Industries, Ltd.), Polyflon (manufactured by Daikin Industries, Ltd.), Hostaflon (manufactured by Daikin Industries, Ltd.),
Hoechst) and other registered trademark names and recycled Teflon. I, niT-
It is a type of fluororesin commercially available as 300H (manufactured by Kitamura Co., Ltd.), and although compression molding and extrusion molding are possible, ordinary injection molding is impossible. preferable.

Next, the thermoplastic polyimide resin of the present invention uses an ether diamine represented by (in the formula, X and R1-R4 are the same as before) as a diamine component, and this and one or more tetracarboxylic acid diamines. It is a polyimide obtained by dehydrating and cyclizing a polyamic acid obtained by reacting it with an anhydride.

The dinamine used in this method includes bis(4-(
3-aminophenoxy)phenylcomethane, 1.1-bis(4-(3-aminophenoxy)phenyl]ethane,
l, 2-bis(4-(3-aminophenoxy)phenyl)ethane, 2.2-bis(4-(3-aminophenoxy)phenyl)propane, 2-(4-(3-aminophenoxy)phenyl) L2 - (4L(3-aminophenoxy)-3-methylphenyl)propane, 2.2-
Bis(4-(3-aminophenoxy)-3-methylphenyl]propane, 2-(4-43-aminophenoxy)phenyl)-2-(4-(3-aminophenoxy)-3,5-dimethylphenyl) Propane, 2,2-bis(4-(3-aminophenoxy)-3,5-dimethylphenyl)propane, 2,2-bis(4-(3-aminophenoxy)phenylcobutane, 2,2-bis( 4-(
3-aminophenoxy)phenyl-1,1,1,3,3
, 3-hexafluoropropane, 4,4'-bis(3-
aminophenoxy)biphenyl, 4,4'-bis(3-
aminophenoxy)-3-methylbiphenyl, 4.4'
-bis(3-aminophenoxy)-3,3'-dimethylbiphenyl, 4,4'-bis(3-aminophenoxy)
-3,5-dimethylbiphenyl, 4゜4'-bis(3-
aminophenoxy) -3,3',5,5'-tetramethylbiphenyl, bis(4-(3-aminophenoxy)phenyl koketone, bis(4-(3-aminophenoxy)phenyl fusulfide, bis(4 Examples include -(3-aminophenoxy)phenyl]sulfone, which may be used alone or in combination of two or more.

Further, other diamines may be mixed and used within a range that does not impair the melt fluidity of the thermoplastic polyimide resin. Examples of diamines that can be used in combination include -aminobenzylamine, p-aminobenzylamine, 3.3'-diaminodiphenyl ether, 3.
4'-diaminodiphenyl ether, 4.4'-diaminodiphenyl ether, 3.3'-diaminodiphenyl sulfide, 3.4'-diaminodiphenyl sulfide, 4.4'-diaminodiphenyl sulfide,
3.3'-diaminodiphenylsulfone, 3.4'-diaminodiphenylsulfone, 4.4'-diaminodiphenylsulfone, 3.3'-diaminobenzophenone, 3
．． 4'-Diaminobenzophenone, 4.4'-Diaminobenzophenone, 1.3-bis(3-aminophenoxy)benzene, 1.3-bis(4-aminophenoxy)benzene, 1.4-bis(3- aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene,
2.2-bis(4-(4-aminophenoxy)phenyl]propane, 4.4'-bis(4-aminophenoxy)biphenyl, 4.4'-bis(4-aminophenoxy)ketone, bis(4-( 4-aminophenoxy)phenyl]
- Sulfide, bis[4-(4-aminophenoxy)phenyl]sulfone, etc. are mentioned, and these diamines are usually used in a mixture of 30% or less, preferably 5% or less.

The thermoplastic polyimide resin particularly preferably used in the present invention is obtained by reacting the diamine and tetracarboxylic dianhydride in an organic solvent and dehydrating and ring-closing the resin. The tetracarboxylic dianhydride used in this method is a tetracarboxylic dianhydride represented by 2 (wherein Y is the same as before). That is, examples of the tetracarboxylic dianhydride used include ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, cyclopentanecarboxylic dianhydride, and pyromellitic dianhydride. Acid dianhydride, 3.3'.

4.4'-benzophenone tetracarboxylic dianhydride,
2.2', 3.3'-benzophenonetetracarboxylic dianhydride, 3.3', 4.4'-biphenyltetracarboxylic dianhydride, 2.2', 3.3'-
Biphenyltetracarboxylic dianhydride, bis(3,4-
dicarboxyphenyl)ether dianhydride, bis(3,
4-dicarboxyphenyl)sulfonic anhydride, 1.1
-Bis(2,3-dicarboxyphenyl)ethannihydride, bis(2,3-dicarboxyphenyl)methannihydride, bis(3,4-dicarboxyphenyl)methannihydride, 2.3.6.7 -Naphthalenetetracarboxylic dianhydride, 1.4.5.8-naphthalenetetracarboxylic dianhydride, 1,2.5.6-naphthalenetetracarboxylic dianhydride, 1.2.3.4-benzene Tetracarboxylic dianhydride, 3.4.9.10-perylenetetracarboxylic dianhydride, 2.3.6.7-tyndra7inetetracarboxylic dianhydride, 1.2.7.8-phenanthrene Tetracarboxylic dianhydride, 4.4'-(p-phenylenedioxy)cyphthalic dianhydride, 4*4'-(s-
Examples include phenylenedioxy) cyphthalic dianhydride. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

22. In order to enhance the effect of this invention, the average particle size of the thermoplastic polyimide resin powder should be 50. It is desirable that the particle size is less than n, because if the powder has a large average particle size of more than 50n, it will be difficult to uniformly disperse the thermoplastic polyimide resin in PTFE, which will affect compression creep resistance, sealing properties, abrasion resistance, etc. Therefore, no significant improvement can be expected. In addition, the amount added is preferably 100 parts by weight of PTFE, but this means that if the thermoplastic polyimide resin powder is added in a small amount of less than 3 parts by weight, no significant modification effect can be expected; This is because the increased cost would be greater than the effect of increasing the amount, which is not economically desirable.

Furthermore, the inorganic filler used in combination with this invention improves the wear resistance of PTFH, and includes, for example, glass fiber, glass beads, carbon fiber, silicon nitride, boron nitride, etc., and the amount of these additives is determined by , 3 to 30 parts by weight per 100 parts by weight of the filler is preferable, because if the filler is in a small amount of less than 3 parts by weight, there will be no effect of improving wear resistance, and if it is in a large amount exceeding 30 parts by weight, the friction properties will be deteriorated. ,
This is because it deteriorates mechanical properties, which is undesirable.

Note that antioxidants, heat stabilizers, ultraviolet absorbers, colorants, flame retardants, antistatic agents, crystallization promoters, etc. may be added as appropriate within a range that does not impair the purpose of the present invention.

The above-mentioned PTFE, thermoplastic polyimide resin, and filler may be mixed and molded using conventionally widely used methods, such as dry mixing of each powder in a mixer such as a tumbler mixer or a Henschel mixer. Then, put this into a mold and make 380 to 600 kg/
After preforming by applying CD pressure, the entire mold may be heated and sintered at 385° C. or higher, or other methods such as heating and pressurizing, continuous molding using a ram extruder, etc. may be used.

[Effect]

Since the polyimide resin contained in the composition of the present invention is thermoplastic, it is thought that it melts at the melting point and forms a network by filling the gaps between the PTFE particles.As a result, the base material PTFE is This exhibits the effect of significantly improving creep resistance, which has been considered a drawback up to now, without impairing the excellent sliding properties that it has.

〔Example〕

The raw materials used in the actual examples and comparative examples are listed below. Note that all of these blending proportions are parts by weight.

■ Thermoplastic polyimide resin It was manufactured by the method shown in Synthesis Example-1.

■ Thermosetting polyimide resin (manufactured by Temple, Rose-Boulin: Kerimide 1000, average particle size 2G1m) ■ Glass fiber (manufactured by Asahi Fiberglass = M12-80) ■ Glass beads (manufactured by Toshiba Varotini: 1ICB)
731, average particle size 30n) ■Polyphenylene sulfide (PPS) (manufactured by Phillips Petroleus, USA: Ryton PP5-P4)
■PTFI! (manufactured by Kitamurasha: IIT, 30011
)■ Graphite (manufactured by Nippon Graphite Co., Ltd.: ^CP).

Synthesis Example 1 = Production of thermoplastic polyimide resin In a reaction vessel equipped with a stirrer, reflux cooling, and nitrogen introduction tube, 3.68 kg (10 mol) of 4,4'-bis(3-aminophenoxy)biphenyl, 32.9 kg of N,N-dimethylacetamide was charged, and 2.125 kg of pyromellitic dianhydride (9,75
mol) was added while being careful not to increase the solution temperature, and the mixture was stirred at room temperature for about 20 hours.

Add 2.0% to this polyamic acid solution at room temperature under a nitrogen atmosphere.
2 kg (20 mol) of triethylamine and 2.
55 kg (25 mol) of acetic anhydride were added dropwise. The mixture was stirred at room temperature for about 20 hours to obtain a pale yellow slurry. This slurry was filtered, washed with methanol, filtered,
Dry under reduced pressure at °C for 8 hours to obtain 5.28 kg (yield approximately 97%)
polyimide powder was obtained. The logarithmic viscosity of this polyimide powder was 0.70 dl/g.

Here, the logarithmic viscosity is calculated by adding 0.5 g of polyimide powder to a 100-dish plate of solvent (p-chlorophenol-J: phenol-90j).
This is the value measured by heating and dissolving at 1O2 weight ratio) and cooling to 35°C.

Examples 1 to 58 Raw materials mixed at the proportions shown in Table 1 and Table 1 and thoroughly mixed using a Henschel mixer were filled into a cylindrical mold with an inner diameter of 30 u, and preformed under a pressure of 450 kg/c4. rear,
The entire mold was heated in an electric furnace to a temperature of 385°C or higher, and then immediately taken out, a pressure of 600 kg/d was applied, and the mold was allowed to cool to obtain a molded body. Test pieces having dimensions and shapes specified by various test methods were prepared from this molded body. Note that the above molding method is just an example, and is not limited to this. Here, the test method for determining each characteristic value is as follows.

(1) Compression creep deformation rate (%): ASTM-0
6214: Complying with the load of 140 kg/cd and 24 hours, the compression creep deformation rate (%) is determined.

(2) Tensile strength (kg/cd) and elongation (%
): According to 8 STM-0638.

(3) Coefficient of Friction The coefficient of friction was determined using a Ni-last type friction tester at a sliding speed of 150 m/min, a load of 1 kg/d, the mating material was a bearing I 5UJ-2 (quenched and ground finished), and no lubrication.

(4) Wear coefficient (X 10-'・d/kg-m) Sliding speed of 128 m/min by Nilast type abrasion tester, load 0.78 kg/cj, mating material is bearing steel 5UJ-2 (quenched and ground finish) Find the wear coefficient under no-lubrication conditions.

(5) Sealing performance of seal ring: The amount of oil leakage (ml) from the seal ring shown in the figure was measured. In this testing machine, a piston 3 is inserted into a cylinder 2 that rotates together with a pulley 1, and this piston 3 has seal rings 5 and 5 attached to two ring grooves 4 and 4' provided at the tip. The oil injected from the oil inlet A is sealed between the seal rings 5 and 5'. Therefore, piston 3
The sealing properties of the seal rings 5 and 5' can be measured by rotating the pulley 1 while fixing the seal ring 5 and the amount of oil leaking from the oil outlets B and C. The measurement conditions are as follows.

Sample: Straight cut product, after running in a test machine at 100℃ for 1 hour, Oil: Automatic transmission oil Dexilon ■, hydraulic pressure 3 kg
/d1 Oil temperature: 40° C. Cylinder rotation speed: 50 GO rpm The above test results are summarized in Table 2.

Comparative Examples 1 to 6: Test pieces were prepared in the same manner as in the examples except that the raw materials were mixed in the proportions shown in Table 3.
Each characteristic value was determined. The results obtained are summarized in Table 4.

Table 2 Table 3 Table 4 First of all, from Table 2, in Examples 1 to 5, the creep resistance and seal resistance were all significantly improved, and at the same time, the friction properties were significantly improved. It can be seen that there are no visible effects. On the other hand, in Comparative Example 1, the amount of thermoplastic polyimide resin added was less than the specified amount, so there was no effect on creep resistance and sealing resistance. A thermosetting polyimide resin was added instead of a polyimide resin, and although the creep resistance and seal resistance were improved, they were still not insufficient. Furthermore, in Comparative Examples 3 to 5, when only the filler was added, Therefore, Comparative Example 3 had particularly poor wear resistance, and Comparative Examples 3 to 5 were all significantly inferior in their effects on creep resistance and sealing resistance. In Comparative Example 6, filler was not added. It can be seen that the wear resistance is very poor.

〔effect〕

The composition of the present invention sufficiently retains the excellent frictional properties inherent to the base material tetrafluoroethylene resin, while also having superior compression creep properties and sealing performance, which is unprecedented in the art. Therefore, it can be said that it is the most suitable material for sealing materials, especially seal ring molding materials.

Therefore, it can be said that the significance of this invention is extremely large.

[Brief explanation of the drawing]

The figure is a partially cutaway side view of a seal ring oil leakage measurement tester used to measure seal performance in an embodiment of the present invention. 1... Pulley, 2... Cylinder, 3... Piston, 4.4'.
...Ring groove, 5.5'...Seal ring, A...Oil inlet, B, C...Oil outlet.

Claims (1)

[Claims] (1) 100 parts by weight of tetrafluoroethylene resin and general formula ▲
There are mathematical formulas, chemical formulas, tables, etc. (where X is a direct bond, 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, or a sulfone group). R_1 to R_4 represent hydrogen, lower alkyl group, lower alkoxy group, chlorine or bromine, and may be the same or different from each other. Y is an aliphatic group having 2 or more carbon atoms, cyclic A tetravalent group selected from the group consisting of an aliphatic group, a monocyclic aromatic group, a fused polycyclic aromatic group, and a non-fused polycyclic aromatic group in which aromatic groups are interconnected directly or through a bridge member. 1. A tetrafluoroethylene resin composition comprising, as essential components, 3 to 50 parts by weight of a thermoplastic polyimide resin comprising repeating units represented by the following (representing a group) and 3 to 30 parts by weight of an inorganic filler.