JP3049082B2 - Sintered molded body of ethylene tetrafluoride resin composition - Google Patents

Description

The present invention relates to an ethylene tetrafluoride resin composition useful as a material for a sliding portion.

[Conventional technology]

Polytetrafluoroethylene resin (hereinafter abbreviated as PTFE)
Is not only excellent in heat resistance and chemical resistance, but also has a low coefficient of friction and self-lubrication, so it is a material for sliding parts such as bearings and gears, pipes, valves, and other molded products, so-called engineering plastics. Although it has been widely used in various fields as a typical example, the wear resistance and creep resistance are not always satisfactory, and many attempts have been made to improve the wear resistance and creep resistance by adding various fillers. Was. As the filler, an inorganic filler such as glass fiber powder, glass beads, carbon fiber, graphite, molybdenum disulfide or an aromatic polyester, polyphenylene sulfide, aromatic polyamide, polyamide imide, polyether ether ketone, polyimide, etc. Organic fillers and the like. However, when the inorganic filler is added, when the mating material at the time of sliding is a soft metal such as stainless steel, aluminum alloy, phosphor bronze, etc., the mating material is damaged, which is not preferable. When an organic filler that does not melt at the molding temperature of PTFE (320 to 360 ° C) is added to PTFE, the creep resistance is not improved and the abrasion resistance is poor. There is a point.

Further, when an organic filler that melts at the molding temperature of PTFE is added to PTFE, JP-A-63-118357, JP-A-1-22331
As shown in No. 50, the molten organic filler is PTFE
To remove the gap between particles and form a network, PT
Although the creep resistance and abrasion resistance of FE are improved, there is a problem in that the friction characteristics of the organic filler itself are affected and the inherent friction characteristics of PTFE are impaired.

[Problems to be solved by the invention]

The problem of the present invention is that PTFE was difficult with the conventional technology.
An object of the present invention is to provide a PTFE composition having excellent creep resistance, abrasion resistance and friction characteristics without impairing the inherent properties such as excellent heat resistance, chemical resistance and self-lubricating property.

[Means for solving the problem]

In order to solve the above problems, the present invention provides a PTFE powder 50.
A means for producing a sintered molded article of an ethylene tetrafluoride resin composition containing about 95% by weight and 50 to 5% by weight of a polycyanoaryl ether resin powder having an average particle size of 1 to 70 μm was adopted. The details are described below.

First, PTFE in the present invention is a homopolymer of tetrafluoroethylene (tetrafluoroethylene), and is composed of Algoflon (manufactured by Montedison, Italy), Teflon (manufactured by DuPont, USA), Fluon (ICI, UK) Company),
Polyfluorocarbon (manufactured by Daikin Industries, Ltd.) is a fluororesin marketed under a trade name, such as a resin that can be compression-molded and extruded, but cannot be injection-molded normally,
Further, in the present invention, a powdery material is preferable.

Next, the polycyano aryl ether resin in the present invention is represented by the formula Or a repeating unit represented by the formula (Where Ar is The polymer is a polymer in which a repeating unit represented by the following formula (1) is present in an amount of 20 mol% or less so that the original characteristics of the polycyano aryl ether resin are not lost. Such a polycyano aryl ether resin is prepared by reducing the viscosity of a 0.2 g / dl solution of P-chlorophenol at 60 ° C. (ηsp /
It is preferable that c) is 0.3 dl / g or more. Polycyano aryl ether resins satisfying such conditions include, for example, Izumi Kosan Co., Ltd., polyether nitrile: ID3
00. The production of the polycyano aryl ether may be carried out by a conventionally known method disclosed in JP-A-63-3059 and others. As such a polycyano aryl ether resin, a powder obtained after polymerization may be used as it is, or may be finely pulverized using a pulverizer such as a freezing pulverizer, a hammer mill, a ball mill, and a mass colloider. The average particle size of the polycyano aryl ether resin is preferably 1 to 70 μm. Regardless of whether the average particle size is smaller than 1 μm or larger than 70 μm, it becomes difficult to uniformly disperse the polycyanoaryl ether resin in PTFE, and the wear resistance, lubrication properties and creep resistance A remarkable modifying effect such as characteristics cannot be expected. A particularly preferred average particle size is 3 to 40 μm.

The addition amount of this polycyano aryl ether resin is PT
Preferably, the content is 50 to 5% by weight based on 50 to 95% by weight of FE. Because the polycyano aryl ether resin is 5
If the amount is less than 50% by weight, the wear resistance and the creep resistance cannot be improved. On the other hand, if the amount exceeds 50% by weight, the frictional characteristics and the moldability are deteriorated.

The mixture obtained at the above mixing ratio may be molded under the usual molding conditions of PTFE containing a filler, which has been widely used conventionally.For example, PTFE and polycyano aryl ether are mixed by a mixer such as a tumbler mixer and a Hensiel mixer. Dry-mix the resin and put it in a mold to make 380-6
After applying a pressure of 00 kg / cm ^{2 and} preforming, a method of sintering the compression molded body taken out of the mold at 370 ° C., a method of batch compression molding while applying heat and pressure, or a continuous method using a ram extruder Any method such as a molding method may be used.

[Action]

The sintered molded article of the tetrafluoroethylene resin composition of the present invention, the polycyano aryl ether resin of the composition is melted at the molding temperature of PTFE to form a network by wetting the gaps between the PTFE particles, the PTFE composition This greatly improves the creep resistance and abrasion resistance of PTFE and makes use of the excellent friction characteristics of PTFE.

〔Example〕

Raw materials used in Examples and Comparative Examples are collectively shown as follows. The abbreviations are shown in parentheses.

PTFE Made by DuPont-Mitsui Fluorochemicals: TG-7J (PTFE-
1) PTFE Hoechst: TFE1700 (PTFE-2) Polycyano aryl ether resin Idemitsu Kosan: Polyethernitrile ID300 (finely pulverized with a freeze mill, average particle size 10 μm) (PEN) Polyetheretherketone Resin Made by ICI of the UK: Victrex PEEK-150P
(Pulverized with a freeze grinder) (PEEK) Air freshener Polyester manufactured by Sumitomo Chemical Co., Ltd .: Econol E101SS (OBP) Polyphenylene sulfide resin manufactured by Philippe Petroleum Co .: Ryton PPS-P4 (P
PS) Carbon fiber: M207S (CF) manufactured by Kureha Chemical Industry Co., Ltd. After dry-mixing the above raw materials at the ratios shown in Table 1, filling them in a mold with an inner diameter of 30 mm and applying a pressure of 450 kgf / cm ² Preforming was performed, and the obtained preformed body was heated at 360 ° C. for 3 hours to form a sintered formed body. From this formed body, test pieces having dimensions and shapes specified in various test methods were produced. The test method for obtaining each physical property value is as follows.

(1) Compression creep deformation rate (%): Determine the compression creep deformation rate (%) under a load of 140 kgf / cm ² and 24 hours in accordance with ASTM-D621.

(2) Friction coefficient: Sliding speed by thrust type friction tester 30m / min, load 5
kgf / cm ² , the mating material stainless steel SUS304 or aluminum alloy ADC-12, and the coefficient of friction under non-lubricated conditions are determined.

(3) Wear coefficient (× 10 ⁻¹⁰ cm ³ / kg · m): Sliding speed by a thrust type abrasion tester 30 m / min, load 5
kgf / cm ² , stainless steel SUS304 or aluminum alloy ADC-12, wear coefficient under non-lubricated condition.

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

As is evident from Table 1, the PTFE compositions to which the polycyanoaryl ether resins of Examples 1 to 3 were added,
In addition to the compressive creep deformation rates substantially equal to those of Comparative Examples 1 to 4 using fillers other than the above, the values of the friction coefficient and the wear coefficient were low, and remarkable friction and wear characteristics were exhibited. On the other hand, in Comparative Example 1, the friction and wear characteristics were inferior due to the characteristics of PEEK. In Comparative Example 2 or Comparative Example 3, the wear coefficient was extremely high. In Comparative Example 4, in which the filler was carbon fiber, the coefficient of wear was extremely high with respect to the aluminum alloy as the mating material.

〔effect〕

The sintered molded article of the tetrafluoroethylene resin composition of the present invention has the inherent chemical resistance and sealing properties of the tetrafluoroethylene resin, and further has excellent creep resistance properties, friction properties and wear properties. It can be said that the material is optimal and highly useful as a material for a sliding portion such as a bearing or a material for a sealing portion such as a seal ring.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // (C08L 27/18 71:00) 27:18

Claims (1)

(57) [Claims] 1. An ethylene tetrafluoride resin powder of 50 to 95% by weight.
And a polytetrafluoroethylene resin composition containing 50 to 5% by weight of a polycyanoaryl ether resin powder having an average particle size of 1 to 70 μm.