JPS59231267A - Sliding material - Google Patents

Abstract

PURPOSE:To provide the sliding material of a mechanical seal which has high resistance to chemicals and less friction coefficient and prevents production of blister, by a method wherein pores in the base of a sliding material, such as a carbon material, SiC-covered graphite material, is filled with ethylene tetrafluoride resin to fuse it. CONSTITUTION:Pores in the base of a sliding material are impregnated with ethylene tetrafluoride resin serving as suspension in which the powder of said resin is dispersed in liquid. Water is preferably used as dispersing agent. The grain size of resin powder is preferably 2mum or less in the case of a sliding base material of carbon having an average pore side of about 20mum. If an ethylene tetrafluoride resin content in suspension is set to 30-60wt%, impregnation efficiency is excellent. After the pores in the base material are impregnated with suspension by a well-known vacuum pressurizing impregnation and other means, the work is dried and freed from dispersing agent, and is then heated to a resin fusing temperature to fuse it to the inside of the pore.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in sliding materials used in mechanical seals and the like.

Conventionally, carbon materials have often been used as sliding materials for the above purpose due to their good lubricity, and in order to improve airtightness, thermosetting resins such as 7-enol resin and furan resin have been added to the carbon materials. It is used by impregnating it with However, sliding materials impregnated with such resin have problems with the chemical resistance of the resin.
It had drawbacks such as a high coefficient of friction and the tendency to form blisters.

An object of the present invention is to provide a sliding material that eliminates the above-mentioned drawbacks.

The present invention relates to a sliding material formed by filling the pores of a sliding material base material with tetrafluoroethylene resin and fusing the same.

In the present invention, a carbon material, a SiC-coated graphite material, a ceramic material, or the like is used as the sliding material base material, and there are no particular limitations as long as it has chemical resistance and mechanical strength depending on the purpose of use.

Tetrafluoroethylene resin (hereinafter referred to as PTFE resin).

The powder is dispersed in a liquid and is impregnated into the pores of the sliding material base material as a suspension. There are no restrictions on the dispersion medium for the suspension, but water is preferred because it is easy to handle.

The particle size of the PTFE resin powder is not limited as long as it can be selected depending on the pore size of the sliding material base material.9 For example, since the average pore diameter of a carbon sliding material base material is usually 20 μm, it is preferably 2 μm or less. . This is because if it exceeds 2 μm, crosslinking tends to occur at the entrance of the pores, which may make impregnation difficult. The content of the PTFE resin in the suspension is preferably in the range of 30 to 60% by weight in terms of impregnation efficiency. The above suspension is impregnated into the pores of the sliding material base material by a known method such as vacuum pressure impregnation.

The dispersion medium is removed by drying, and then heated to the melting temperature of the PTFE resin to fuse it into the pores.

Next, the present invention will be explained with reference to examples.

Example 1 Two carbon materials (manufactured by Hitachi Chemical Co., Ltd., trade name HCB-10) were
It was processed into a ring-shaped sliding material base material in the order of 5flllφ×20×φ×20. Put this in an impregnated container and maintain 2mmHg''
! After reducing the pressure with
Manufactured by Polyphron Day Snowman.

Polyfluorocarbon (polyfluorocarbon content: 60% by weight) with an average particle size of 0.3 μm was injected, and the IOK was further pressurized to 7 cm2 with compressed air, held for 1 hour, returned to normal pressure, taken out, and placed in an electric furnace at 110°C for 3 hours. Heat to remove water.

Next, the temperature was gradually increased to 400° C. for 3 hours to fuse the PTFE resin to the pores.

Example 2 SiC coated graphite material (manufactured by Hitachi Chemical Co., Ltd., trade name H8C,
Dimensions: 251+1111φ x 20 area φX201111+
1h) PTFE resin was fused to the pores of the dry sliding material base material in the same manner as in Example 1.

Example 3 Relative density 65cm 9 dimensions are 25mm φ x 20■φ x 20wm
A ring-shaped alumina sintered body was manufactured, and PTFE was fused to the pores in the same manner as in Example 1.

Example 4 Relative density 70%, dimensions are 25 order φ x 20Mφ x 201W
A ring-shaped SiC sintered body of Ih was produced, and PTFE was fused to the pores in the same manner as in Example 1.

Comparative Example 1 The sliding material base materials in each of the above Examples were placed in an impregnation container in the same manner as in Example 1, and the pressure was reduced to 2+nmHg, and then a phenol resin (manufactured by Hitachi Chemical Co., Ltd., trade name DP-2000, resin content: 5
0 weight) and then compressed air! After pressurizing to 1110/crn2 and holding for 1 hour, the pressure was returned to normal pressure and taken out, and after air-drying, the temperature was raised to 250° C. for heat curing.

Comparative Example 2 Furan resin (manufactured by Hitachi Chemical Co., Ltd., trade name: VF303) was vacuum impregnated into the sliding material base material in each of the above Examples in the same manner as in Comparative Example 1, and then thermally cured.

The sliding materials obtained in Comparative Example 1 and Comparative Example 2 are summarized as shown in Table 1.

Table 1 The sliding materials obtained in each of the above Examples, Comparative Example 1, and Comparative Example 2 were subjected to a friction property test in water at 20° C. using a Matsubara friction and wear tester (manufactured by Toyo Baldwin). The mating material is a sliding base material.

In the case of carbon, an alumina sintered body with a relative density of 96 cm.

The SiC-coated graphite material was a KSiC-coated graphite material, the alumina sintered body was an alumina sintered body with a relative density of 99.51, and the SiC sintered body was an 8iC sintered body with a relative density of 98 degrees. The relationship between PV value and friction coefficient is shown in Figure 1 and
It is shown in FIGS. 2, 3 and 4. As can be seen from the figure, the sliding material according to the embodiment of the present invention has a lower coefficient of friction and a higher PV compared to the conventional sliding material impregnated with phenolic resin or furan resin.
In particular, the sliding materials of Examples 1 and 2 showed remarkable effects without burning up to a value of 5-.

Next, the sliding material of Example 1 was attached to the mechanical seal part of a centrifugal pump (manufactured by Zonsoku Seisakusho), and the number of revolutions was 300 Or, I using Highland Oil 90, manufactured by Nippon Oil Co., Ltd.
), m, surface pressure 10 V4/cm”, temperature 20℃, 5
It was operated for 500 hours at each of the five stages of 0℃, 100℃, 150℃ and 200℃, and the presence or absence of blisters, amount of wear,
A test was conducted to check for oil leakage. Similar tests were conducted on the sliding material of Comparative Example 1-2, and the results were
Shown in the table.

As is clear from Table 6, when the sliding material of the present invention is used, there is no occurrence of pristerns or leakage, and the amount of wear is one order of magnitude smaller than that of conventional products.

Also, Example 1. A pressure test was conducted on the sliding materials of Comparative Example 1-1 and Comparative Example 1-2. That is, both sides in the height direction were sealed, soapy water was applied to the outer peripheral surface, and the air pressure shown in Table 3 was applied, and the pressure resistance was examined from the presence or absence of air bubbles on the outer peripheral surface, as shown in Table 3.

The pressure resistance of Comparative Example 1 is 5 to 7 Kg/Crr? On the other hand, the sample of Example 1 showed no abnormality up to 12 Kf/cvi' (in Table 3, the mark ◯ indicates that the pressure test was passed, and the mark X indicates failure).

Furthermore, Example 1. The sliding materials of Comparative Example 1-1 and Comparative Example 2-1 were immersed in the chemical solutions shown in Table 4 at room temperature for 200 hours, and the presence or absence of surface corrosion was observed. The results are shown in Table 4. In the table, an X mark indicates that the surface was corroded by the chemical, and an O mark indicates that the surface was not corroded.

Table 4 As is clear from Table 4, the sliding material of the present invention was not attacked by any of the five types of chemicals.

The sliding material of the present invention has a lower coefficient of friction and higher PV compared to conventional sliding materials impregnated with phenolic resin or furan resin.
It can be used without burning into the value.

It also has excellent chemical resistance and pressure resistance, and when used as a mechanical seal, it has the advantages of no blistering or leakage, and a small amount of wear.

[Brief explanation of drawings]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are graphs showing the relationship between the PV value and the wear coefficient of sliding materials. 1st Fig. 1'Ba Bitter 12.1) Deposit 2 Figure pressure A L (K C≦%Z, de〉 and ()

Claims (1)

[Claims] 1. A sliding material made by filling the pores of a sliding material base material with tetrafluoroethylene resin and fusing it.