JPH04258653A - Tetrafluoroethylene resin composition - Google Patents

Abstract

PURPOSE:To produce the title compsn. excellent in creep resistance, friction characteristics, and abrasion resistance without detriment to the excellent resistance to heat and chemicals and excellent self-lubricity inherent in a tetrafluoroethylene resin. CONSTITUTION:The title compsn. essentially comprises a tetrafluoroethylene resin, an arom. thermoplastic resin which melts at 310-390 deg.C without being decomposed and comprises at least one resin selected from the group consisting of arom. polyetherketone, polycyanoaryl ether, polyamideide, thermoplastic polyimide, arom. polyester, polyethersulfone, polyetherimide and polyarylene sulfide resins, and a heat-resistant resin power, such as a polyimide resin, an arom. polyester resin, or an arom. polyamide resin, which does not melt at 310-390 deg.C.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a tetrafluoroethylene resin composition useful as a material for sliding parts.

0002

[Prior art and its problems] Tetrafluoroethylene resin (
PTFE (hereinafter referred to as PTFE) not only has excellent heat resistance and chemical resistance, but also has a low coefficient of friction and self-lubricating properties, so it can be used as a material for sliding parts such as bearings and gears, as well as for pipes,
Although it has been widely used in various fields as a typical engineering plastic such as valves and other molded products, its wear resistance and creep resistance are not necessarily satisfactory, and it has been developed by adding various fillers. Many attempts have been made to improve the.

Such fillers include inorganic fillers such as glass fiber powder, glass beads, carbon fibers, graphite, and molybdenum disulfide, or aromatic polyester, polyphenylene sulfide, aromatic polyamide, polyamideimide, and polyamide. Examples include organic fillers such as ether ether ketone and polyimide. However, adding an inorganic filler to PTFE is undesirable because it damages the mating material during sliding when it is a soft metal such as stainless steel, aluminum alloy, or phosphor bronze.

[0004] Among organic fillers, when only organic fillers that do not melt at the PTFE molding temperature (310 to 390°C) are added to PTFE, no improvement in creep resistance is observed, and furthermore, wear resistance is There is also the problem that it is inferior to

[0005] In order to improve the above-mentioned creep resistance, P
When an organic filler that melts at the molding temperature of TFE is added to PTFE, it is possible to
As shown in No. 223150, the molten organic filler squeezes through the gaps between the PTFE particles to form a network, which improves the creep resistance properties of PTFE, which was the original objective, but does not improve the wear resistance. , the friction properties are not satisfactory.

[0006]

[Problems to be Solved by the Invention] An object of the present invention is to achieve creep resistance without impairing the inherent excellent properties of PTFE, such as heat resistance, chemical resistance, and self-lubricating properties, which were difficult to solve with conventional techniques. PTF with excellent properties, wear resistance and friction properties
E composition.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention uses a tetrafluoroethylene resin and 310-
They adopted a method in which the essential components are an aromatic thermoplastic resin that melts without thermal decomposition at 390°C, and a heat-resistant resin powder that does not melt at 310 to 390°C. The details will be described below.

First, PTFE in this invention is a homopolymer of tetrafluoroethylene (tetrafluoroethylene), and includes Hyflon (manufactured by Montegisson, Italy), Teflon (manufactured by DuPont, USA), and Fluon (manufactured by I.P., UK). It is a fluororesin commercially available under trade names such as C.I. Co., Ltd.) and Polyflon (Daikin Industries, Ltd.),
It is a resin that gels at 90° C. and can be compression molded and extruded, but cannot be molded by ordinary injection molding. Furthermore, in the present invention, a powdered resin is preferable because it is easy to mix homogeneously.

[0009] Next, the temperature of 310 to 390°C in this invention
The aromatic thermoplastic resin that melts without thermal decomposition is PT.
At 310 to 390 degrees Celsius, which is the molding temperature of FE, the regular molecular arrangement is disrupted and molecular movement becomes free, but molecular chains are not cut to reduce the molecular weight, and the melt viscosity is 1 × 1.
03 to 105 poise is preferred. Such aromatic thermoplastic resins include aromatic polyetherketone resin, polycyanoaryl ether resin, polyamideimide resin, thermoplastic polyimide resin, aromatic polyester resin, polyethersulfone resin, polyetherimide resin, and It may be one or more resin compositions selected from the group consisting of polyarylene sulfide resins. Furthermore, among the above-mentioned group, aromatic polyether ketone resins, polycyanoaryl ether resins, polyamideimide resins, and thermoplastic polyimide resins are particularly preferred in terms of frictional properties.

[0010] Here, the above-mentioned aromatic polyetherketone resin is, for example,

[0011]

[Chemical formula 1]

An example is a polyetheretherketone resin which is a polymer consisting of repeating units represented by the formula:

[0013]

[Case 2]

Victrex PEK220G, a polymer consisting of repeating units shown by
(manufactured by Ai Corporation), Kadel E-1000 (manufactured by Amoco Corporation, USA)
For example, PEK is commercially available under the trade name of .

[0015] The above polycyanoarylether resin (hereinafter abbreviated as PCAE) has the formula

0016
]

[Chemical formula 3]

The repeating unit represented by the formula

[0018]

[C4]

This is a polymer in which repeating units shown by the following formula coexist. As a commercially available PCAE that satisfies these conditions, polyether nitrile (manufactured by Idemitsu Kosan Co., Ltd.: ID30
0).

[0020] Furthermore, the thermoplastic polyimide resin has the formula

0
021]

[C5]

It is a polymer consisting of repeating units represented by the following formula, and polyimide resin powder manufactured by Mitsui Toatsu Chemical Co., Ltd. can be exemplified.

[0023] The heat-resistant resin powder in the present invention is a heat-resistant resin powder that does not melt at the molding temperature of the above-mentioned tetrafluoroethylene resin at 310 to 390°C. As a heat-resistant resin powder that satisfies these conditions, for example:

[
0024

[C6]

Examples include powders of non-melting polyimide resins having a repeating structure shown in the following. This powder is obtained by finely pulverizing a non-melting polyimide resin. Specifically, for example, Kapton, a film-like non-melting polyimide resin manufactured by DuPont in the United States, is used as a material, and is processed using a hammer mill, a ball mill, It is obtained by finely pulverizing it with a pulverizer such as a masscolyzer or frozen pulverizer. Examples of commercially available fine powder PI include PWA-10 and PWA-20 manufactured by Mikasa Sangyo Co., Ltd.

[0026] Also, there are other formulas

[0027]

[C7]

Examples include non-melting polyimide resins consisting of repeating units represented by the following formula. This consists of a tetracarboxylic acid component whose main component is biphenyltetracarboxylic acid,
It is obtained by polymerizing and imidizing an aromatic diamine component whose main component is diaminodiphenyl ether or para-phenylene diamine. As a commercially available product of such non-melting polyimide resin powder, Iupimol R manufactured by Ube Industries, Ltd.
, Iupimol S can be exemplified.

Other heat-resistant resin powders include non-melting aromatic polyester resins and aromatic polyamide resins.

The aromatic thermoplastic resin that melts without being thermally decomposed at the molding temperature of PTFE is used in powder form as a molding material, but the particle size and the above-mentioned PTFE
It is desirable that the average particle size of the heat-resistant resin powder that does not melt at the molding temperature is 1 to 70 μm. Whether the average particle size is smaller than 1 μm or larger than 70 μm, it becomes difficult to uniformly disperse the aromatic thermoplastic resin or heat-resistant resin powder in PTFE, resulting in poor wear resistance. , significant modification effects such as lubricating properties and creep resistance properties cannot be expected. A particularly preferable average particle size is 3~
It is 40 μm.

[0031] The blending amount of the above materials is PTFE40~
90% by weight, 5-40% by weight of aromatic thermoplastic resin that melts without thermal decomposition at 310-390°C, PTFE
The amount of heat-resistant resin powder that does not melt at a molding temperature of 5 to 40% by weight is preferably 5 to 40% by weight. This is because if the amount of aromatic thermoplastic resin and heat-resistant resin powder is less than 5% by weight, PT
This is because the wear resistance and creep resistance properties of FE cannot be improved, and on the other hand, if the amount exceeds 40% by weight, the friction properties, moldability, etc. will deteriorate, which is undesirable.

[0032] The mixture obtained at the above blending ratio may be molded under the usual molding conditions for filler-containing PTFE, which has been widely used in the past. Dry mix the ingredients, put this into a mold and press 380
After preforming by applying a pressure of ~600 kg/cm2, the compression molded body taken out from the mold is sintered at 370°C, other methods include batch compression molding while heating and pressurizing, or continuous compression molding using a ram extruder. Any molding method may be used.

[0033]

[Function] In the tetrafluoroethylene resin composition of the present invention, the aromatic thermoplastic resin, which is in a molten state without being thermally decomposed at the molding temperature of PTFE, melts at the molding temperature of PTFE to form PTFE particles. Since it forms a network through the gaps between the PTFE particles, the creep resistance and wear resistance properties of the PTFE composition are greatly improved.In addition, the heat-resistant resin powder, which does not melt at the PTFE molding temperature, forms a network between the PTFE particles. It is thought that the abrasion resistance of the PTFE composition is further significantly improved by penetrating finely into the aromatic thermoplastic resin forming the PTFE composition.

[0034]

[Examples] The raw materials used in the examples and comparative examples are listed below. In addition, each abbreviation is shown in parentheses.

(I) PTFE ■ (PTFE-1) Manufactured by DuPont Mitsui Fluorochemical Co., Ltd.:
TG-7J ■(PTFE-2) Manufactured by Hoechst: TFM1700 (I
I) Aromatic thermoplastic resin that melts without thermal decomposition at the molding temperature of PTFE (310-390°C) ■Polyetheretherketone resin Manufactured by ICI Ltd. in the UK: Victrex PEEK-
150P (finely pulverized using a frozen pulverizer) (PEEK
) ■Polycyanoaryl ether resin Manufactured by Idemitsu Kosan Co., Ltd.: Polyether nitrile ID300 (finely pulverized with a frozen pulverizer, average particle size 10 μm) (PE
N) ■PEK Manufactured by ICI UK: Polyetherketone 220
G (finely pulverized using a frozen pulverizer, average particle size 10μ)
m) (PEK) (III) Heat-resistant resin powder that does not melt at the molding temperature of PTFE ■Non-melting polyimide resin Manufactured by Mikasa Sangyo Co., Ltd.: Polyimide resin powder PWA10 (PI-
1) ■Non-melting polyimide resin manufactured by Ube Industries: Iupimol S type (PI-2)■
Non-melting aromatic polyester resin manufactured by Sumitomo Chemical Co., Ltd.: Econol E101SS (OBP) (I
V) Filler ■ Carbon fiber manufactured by Kureha Chemical Industry Co., Ltd.: M207S (CF) After dry mixing the above raw materials in the proportions shown in Tables 1 and 2, it was filled into a mold with an inner diameter of 30 mm, and a mold of 450 kgf/cm2 was mixed. Preforming is performed by applying pressure, and the obtained preform is
It was heated at 60° C. for 3 hours to form a sintered compact, and from this compact, test pieces with dimensions and shapes specified in various test methods were produced. The test method for determining each physical property value is as follows.

(1) Compression creep deformation rate (%): AST
Based on M-D621, load 140kgf/cm2,
The compression creep deformation rate (%) for 24 hours is determined.

(2) Friction coefficient: Sliding speed measured by thrust type friction tester 30 m/min, load 5 kgf/cm2, mating material stainless steel SU304 or aluminum alloy AD
C-12. Determine the coefficient of friction under non-lubricated conditions.

(3) Wear coefficient (×10-10 cm3
/kg・m): The wear coefficient is determined using a thrust type abrasion tester at a sliding speed of 30 m/min, a load of 5 kgf/cm2, a mating material of stainless steel SUS304 or aluminum alloy ADC-12, and no lubrication.

Table 1 shows the physical property values obtained by each of the above test methods.
and are also listed in Table 2.

[0040]

[Table 1]

[0041]

[Table 2]

As is clear from the physical property values in Tables 1 and 2, either the aromatic thermoplastic resins with material numbers ■ to ■ or the heat-resistant resin powders with material numbers
Comparative Examples 1 to 4, in which FE was not added, and Comparative Example 5, in which only CF (2) was used as a filler, exhibited particularly high compression creep deformation rates and wear coefficients, and few had friction coefficients of 0.25 or less.

On the other hand, the PTFE compositions of Examples 1 to 6 were
Compression creep deformation rate, friction coefficient, and wear coefficient are all at low levels, and it has excellent creep resistance, friction and wear coefficient.
The wear characteristics were shown.

[0044]

[Effects] As explained above, the tetrafluoroethylene resin composition has the chemical resistance and sealing properties inherent to tetrafluoroethylene resin, and also has excellent creep resistance, friction properties, and wear properties. Therefore, it can be said that it is particularly suitable for materials for sliding parts such as bearings or materials for sealing parts such as seal rings, and has high utility value.

Claims (2)

[Claims] [Claim 1] Tetrafluoroethylene resin, and 310-3
An aromatic thermoplastic resin that melts without thermal decomposition at 90°C;
A tetrafluoroethylene resin composition containing as an essential component a heat-resistant resin powder that does not melt at 310 to 390°C. [Claim 2] The aromatic thermoplastic resin is an aromatic polyetherketone resin, a polycyanoarylether resin,
Polyamide-imide resin, thermoplastic polyimide resin, aromatic polyester resin, polyether sulfone resin,
The tetrafluoroethylene resin composition according to claim 1, which is one or more resins selected from the group consisting of polyetherimide resins and polyarylene sulfide resins.