JPH0472345A - Ethylene tetrafluoride resin composition - Google Patents

Abstract

PURPOSE:To provide a composition improved in abrasion resistance and creep resistance without being impaired in heat resistance, chemical resistance and self-lubricating property and suitable as a material for sliding members or sealing members by adding a specific polyimide resin fine powder to ethylene tetrafluoride resin. CONSTITUTION:(B) Fine powder obtained by grinding a filmy polyimide resin comprising repeating units of the formula e.g. with a hammer or a freezing and grinding machine and having an average particle size of 1-5mum, preferably 3-40mum, is added to (A) tetrafluoroethylene resin comprising tetrafluoroethylene homopolymer preferably having a good creep resistance characteristic preferably in an A:B of 50-95wt.%: 50-5wt.% to provide a tetrafluoroethylene resin composition most suitable as a sliding material for bearings or as sealing materials for sealing members such as seal rings.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a tetrafluoroethylene resin composition useful as a material for sliding parts or seal parts.

[Conventional technology]

Tetrafluoroethylene resin (hereinafter abbreviated as PTFE) not only has excellent heat resistance and chemical resistance, but also has high
Because it has a low coefficient of friction and self-lubricating properties, it has been widely used in various fields as a typical engineering plastic material for sliding parts such as bearings and gears, pipes, valves, and other molded products. However, the wear resistance and creep resistance properties are not always satisfactory, and many attempts have been made to improve these properties by adding various fillers. Examples of the filler include inorganic fillers such as glass fiber powder, glass peas, carbon fiber, graphite, and molybdenum sulfide, and organic fillers such as aromatic polyester, polyphenylene sulfide, aromatic polyamide, and polyamideimide. . However, when an inorganic filler is added, the mating material during sliding is a soft metal such as stainless steel, aluminum alloy, or phosphor bronze, which is undesirable because it damages the mating material. Furthermore, when organic fillers are added, creep resistance cannot be improved;
In order to improve its creep resistance, PTFE with good creep resistance (for example, Hostaflon TFE 1700 manufactured by Hoechst) is used, but conventional organic fillers and PTFE have significantly poor wettability and poor wear resistance. I don't like it at all.

[Problem to be solved by the invention] The problem to be solved by the invention is to
E P has excellent creep resistance and abrasion resistance without sacrificing its original qualities such as excellent heat resistance, chemical resistance, and self-lubricating properties.
Our goal is to provide TFE compositions.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has developed a film-like polyimide resin consisting of repeating units represented by the general formula %.
They adopted a method of adding it to FE.

First, PTFE in this invention is a homopolymer of tetrafluoroethylene (tetrafluoroethylene), including Alboflon (manufactured by Montegisson, Italy), Teflon (manufactured by DuPont, USA), and Fluon (manufactured by ICI, UK). made)
It is a type of fluororesin that is commercially available under registered trademarks such as Polyflon (manufactured by Daikin Industries, Ltd.), and although compression molding is possible, ordinary injection molding is not possible. Preferably, PTFE has good creep resistance and has a compression creep deformation rate of 10% or less, preferably 7% or less under the following test conditions.

Compression creep test〉 Load: 12.5 N/kilometer 2 Time: 100 hours Test piece size: Cylindrical shape φIOXIOmm As such PTFE, for example, Hoechst r
TFM1700”, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.
T(, -70J, etc.) can be exemplified.

Next, the polyimide resin powder in the present invention is a powder of a polyimide resin (hereinafter abbreviated as P1) consisting of repeating units represented by the following -format % formula. It is finely pulverized. Also,
The average particle size is preferably 1 to 50 mm. Whether the average particle size is smaller than 12 or more than 50, it becomes difficult to uniformly disperse the PI powder in PTFE, and the wear resistance, lubrication properties, creep resistance, etc. No improvement effect can be expected. A particularly preferable average particle size of the PI powder is 3 to 40 tna.

Examples of such PI powder include film-like PI, which is commercially available from DuPont in the United States under the trade name ``Kapton'', which is finely pulverized using a pulverizer such as a hammer mill, ball mill, Mascolider, or frozen pulverizer. Yes, for example polyimide resin powder rPWAio manufactured by Mikasa Sangyo.
, , rPWA20''.

The amount of P1 powder added is preferably 50 to 5% by weight of PI powder to 50 to 95% by weight of PTFE.

If the amount of PI powder is as small as 5% by weight, the wear resistance and creep resistance cannot be improved.On the other hand, if the amount exceeds 50% by weight, the lubrication properties, moldability, etc. will deteriorate, which is undesirable.

The mixture obtained with the above blending ratio may be molded under the usual molding conditions for PTFE containing filler j, which has been widely used in the past. Dry mix and put this into a mold and make 380~600kg/
After pre-molding by applying a pressure of 1.5 cm", the compression molded body taken out from the mold is sintered at 370'C, other methods include batchwise compression molding while heating and pressurizing, or continuous molding using a ram extruder. Any method may be used.

[Example] The raw materials used in the Examples and Comparative Examples are listed below. The respective abbreviations are written in parentheses.

■ PTFE Made by DuPont Fluorochemical Company: TG-"i'0J (P
TFE-1) ■ PTFE Manufactured by Hoechst: TFE1700 (PTFE-2) ■
PI powder manufactured by Mikasa Sangyo Co., Ltd.: PWA-20 (PI-1) average particle size 20 pm ■ PI powder manufactured by Mikasa Sangyo Co., Ltd.: PWA-10 (PI-2) average particle size 101 ■ Aromatic polyester manufactured by Sumitomo Chemical Co., Ltd.: Econor EIOISS (OBP) ■ Polyphenylene sulfide Kizukiji Philips Vetrolius: Ryton PP5P4 (PPS) ■ Carbon fiber manufactured by Kureha Chemical Industry Co., Ltd.: M2O7S (CF) Dry mix the above raw materials in the proportions shown in Table 1 After that, inner diameter 3
The preformed body was filled into a mold with a temperature of 100°C and preformed under a pressure of 450kgf/cd, and the obtained preformed body was heated at 360°C.
The mixture was heated 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 (%): According to ASTM-0621! 1! Based on the load 140kgf
/cffl, determine the compression creep deformation rate (%) for 24 hours.

(2) Friction coefficient The friction coefficient is determined using a Nilast type friction tester under the conditions of a sliding speed of 70 m/min, a load of 5 kgf/cd, a mating material of phosphor blue 1c5191, and no lubrication.

(31m Wear Coefficient (XIO-16cjl/kg-m) The wear coefficient is determined using a Nilast type abrasion tester under the conditions of a sliding speed of 70 m/min, a load of 5 kgf/d, a mating material of phosphor bronze C5191, and no lubrication.

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

Table 1 As is clear from Table 1, the PTFE compositions added with PI powder of Examples 1 to 3 have excellent compression creep properties and friction and wear properties, but the PTFE compositions of Comparative Examples 1 to 3 has significantly poorer wear properties.

〔effect〕

The tetrafluoroethylene resin composition of this invention has the chemical resistance and sealing properties inherent to tetrafluoroethylene resin, and in addition to creep resistance and friction properties, it has particularly excellent wear properties, and is particularly useful for bearings. It is ideal for sliding parts or sole parts such as knoll rings.

Patent ratio iJ person Engineering Nutienne Rulon Co., Ltd. same

Claims (1)

[Claims] (1) A polytetrafluoroethylene resin composition containing powder obtained by finely pulverizing a film-like polyimide resin consisting of repeating units represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ to an average particle size of 1 to 50 μm.