JPH11180790A - Carbon material for sliding and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a carbon material for sliding into which a resin or metal is impregnated. SOLUTION: The carbon material has >=1.80 g/cm<3> bulk density, <=0.02 μm average pore radius, <=5 mm<3> /g cumulative pore volume and <=1 mass% water absorption at the ordinary temp. Three natural graphites different from one another in physical properties (preferably two earthy graphites and flake graphite and the earthy graphites are particularly earthy graphite having <=4% volatile matter content and 10-20 μm average particle diameter and earthy graphite having <=2% volatile matter content and 5-10 μm average particle diameter) are blended as carbonaceous starting materials, kneaded with a binder, comminuted and classified. The resultant powder of <=250 μm particle diameter is compacted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding carbon material and a method for producing the same, and more particularly to a resin-impregnated or metal-impregnated sliding material suitable for use as a seal material such as a mechanical seal or a rotary joint seal or various bearing materials. The present invention relates to a working carbon material and a method for producing the same.

[0002] Carbonaceous materials generally have excellent properties such as self-lubricating properties, heat resistance and chemical resistance. Focusing on this point, a sintered carbon material formed by molding a carbonaceous material into a predetermined shape and then sintering the same is used as a sliding member such as a mechanical seal material or a bearing material. Especially in high temperature atmospheres and chemical liquids that cannot be used with general metal sliding materials,
Widely used in fields that dislike the use of lubricants. Furthermore, as the sealing conditions in sliding parts such as mechanical seal materials and bearing materials, that is, the demand for maintaining a state of strong abrasion and good airtightness as long as possible, becomes more severe,
As the sliding performance of the sliding carbon material itself is required to be improved, a resin or a metal-impregnated carbon material is considered to be promising as one of the materials that can meet such a demand. In addition,
In the following description, a resin-impregnated sliding carbon material will be mainly described as a typical example, and a resin-impregnated sliding carbon material may be simply abbreviated as “impregnated carbon material” below.

In order to obtain a sealing material or a bearing material as a product made of such impregnated carbon material, a block-shaped sintered carbon material obtained by sintering a carbonaceous material is first roughened, and then a block material is obtained. The resin is uniformly impregnated throughout. Conventionally, the purpose of impregnating the resin is to use a carbonaceous raw material generally prepared by mixing two types of artificial graphite and natural graphite, and to obtain a relatively fine particle of about 100 mesh as a pulverized product of a kneaded product of this and a binder. Since the sintered carbon material itself is formed and fired, the density of the structure of the sintered carbon material itself after the firing is not so high correspondingly. Therefore, the aim is to increase the density to compensate for this.

[0004] When the impregnation process is completed, a finishing process for dimensioning as a product is performed, but the impregnated carbon material after the process cannot be used immediately as a product sliding material. This is because, due to the cutting of the surface phase at the time of finishing, a relatively large number of relatively open pores are formed on the machined surface, and a structure that easily communicates with the inside and outside of the tissue is formed. If the (impregnated carbon material) is used as it is for a sliding material such as a sealing material or a bearing material, an accident such as liquid leakage is likely to occur during use. Therefore, the impregnated carbon material that has been finished is impregnated with resin again so that the sliding member as a product can exhibit the required mechanical strength, wear resistance, airtightness, and the like during use. The organization has been re-densified to a sufficient degree.

[0005]

As described above, in the case of a block-shaped impregnated carbon material (so-called block material) before the conventional finishing processing, the impregnated carbon material is re-impregnated after the processing to obtain the level of the fineness of the structure. Was not able to be commercialized if it was recovered (re-raised). For this reason, in the case of a manufacturer that performs integrated production from a material to a product, there is a situation that the time and cost required for repeating the same impregnation work are wasted. In addition, if the manufacturer is not an integrated manufacturer but only performs the final product production process, it cannot be commercialized simply by purchasing the impregnated carbon material as a block material from the material manufacturer and setting the required dimensions. After reimpregnation, or after returning to the material maker for reimpregnation, the final product is achieved.
Accordingly, both the finishing maker and the material maker are troubled by the re-impregnation work, and as a result, the productivity is adversely affected, and there is a problem that the cost of the sealing material, the bearing material, and the like as products is increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the denseness of the entire material at the stage at the time of finishing processing, so that the mechanical property is increased accordingly. Impregnated carbon as a block material that can improve strength, abrasion resistance and airtightness, and consequently exhibit sufficient sliding performance even when used as a product without re-impregnation An object of the present invention is to provide a raw material itself and a method suitable for producing such an impregnated carbon material.

[0007]

The sliding carbon material according to the present invention, which has achieved the above object, has a bulk density of 1.80 g / c.
m ³ or more, average pore radius of 0.02 μm or less, cumulative pore volume of 5 mm ³ / g or less, water absorption (normal temperature) of 1 mass
% Or less. This allows
The impregnated carbon material (block material) after the resin impregnation has been completed and the structure of the impregnated carbon material (block material) has been modified to a much denser structure than that of the conventional impregnated carbon material.
Therefore, even if the finishing is performed, the increase in mechanical strength, wear resistance, and airtightness provided with the improvement in the density of the entire material is maintained as the entire material.

Therefore, even if such impregnated carbon material (block material) is finished and processed and immediately used as a product sliding member, fluid does not leak from the sliding portion at the time of use as in the prior art. In addition, a sliding member that can sufficiently maintain stable airtightness can be obtained. Not only that,
It is possible to provide a sliding member having better sliding performance than the conventional re-impregnated carbon material. As a result, it is not necessary to perform re-impregnation work for imparting necessary sliding performance by performing re-densification of the structure as in the related art, thereby improving productivity,
As a result, it is possible to reduce the manufacturing cost of sliding members such as sealing materials and bearing materials as products.

The method for producing a sliding carbon material according to the present invention, which has achieved the above object, comprises the steps of pulverizing and classifying a kneaded material of a carbonaceous raw material and a binder, forming the mixture, and then firing and impregnating the resin. In the method of sequentially performing each process to produce a resin-impregnated sliding carbon material, the carbonaceous raw materials may have different physical properties.
A mixture of the carbonaceous raw materials and the binder is classified into pulverized products having a particle size of 250 μm.
It is a basic feature that a material whose particle size has been adjusted to be not more than m is subjected to molding treatment.

According to this method, a relatively simple adjustment operation of adjusting the particle size of the carbonaceous raw material as the aggregate and the particle size of the raw material (kneaded and crushed product of the carbonaceous raw material and the binder) before molding can be further achieved. A sintered carbon material having a densified structure can be obtained. Therefore, by impregnating the resin into the densified sintered carbon material, the impregnated carbon material itself is much denser than the conventional impregnated carbon material as a whole, and as a result, the mechanical strength Excellent in abrasion resistance and airtightness. Even if it is used as a product sliding material without re-impregnation, it can exhibit at least the same or better sliding performance than conventional materials. An impregnated carbon material as a block material can be obtained.

Hereinafter, the present invention will be described in detail. (1) The inventor of the present invention firstly needs a re-impregnation work after finishing, which has been a problem in the conventional impregnated carbon material, because the material block before finishing, that is, the impregnated carbon material block It was thought that if a denser material could be obtained in the above condition, the airtightness at the time of sliding could be sufficiently maintained even if the material was used as a product sliding material without re-impregnation after processing. Further, in order to obtain such a denser impregnated carbonaceous material block, it is necessary to adjust the type of aggregate and the particle size composition and to adjust the particle size of the raw material (kneaded and crushed product of the carbonaceous raw material and the binder) before molding. We thought that proper control would be an effective solution, and based on that idea, we worked diligently to find an appropriate control method.

As a result, the above object can be finally achieved.
As an invention of a material having a bulk density of 1.80 g / cm^ThreeLess than
Above, the average pore radius is less than 0.02μm and the cumulative pore volume is
5mm ^Three/ G or less, water absorption (normal temperature) is 1 mass% or less
Configuration of "Sliding carbon material of resin or metal impregnated material"
Can be adopted. In addition, the development of a manufacturing method
According to the report, “The kneaded mixture of carbonaceous raw material and binder
After crushing and classifying, molding, then firing, resin impregnation
Are sequentially performed to produce the impregnated carbon material,
The carbonaceous material contains three types of natural graphite with different physical properties
Powder of the kneaded material of the carbonaceous raw material and the binder.
Classify the crushed product and reduce the particle size to 250 μm or less.
Process the product with the adjusted degree).
It could be used.

(2) In the method for producing an impregnated carbon material of the present invention, first, a binder is added to an aggregate made of a mixture of three types of natural graphite having different physical properties as a carbonaceous raw material.
Knead uniformly by means such as a roll. Of the three types of natural graphite, two types of earth graphite and the balance of scale graphite are used as the balance. In particular, two types of earth graphite are used to obtain physical properties having a volatile content of 4% or less and an average particle size of 10 to 20 μm. Earth graphite (hereinafter referred to as "first earth graphite") and earth graphite having a volatile content of 2% or less and an average particle size of 5 to 10 m (hereinafter referred to as "second earth graphite"). With this configuration, further improvement in the strength of the impregnated carbon material and the denseness of the structure can be expected.

The mixing ratio of the first earth graphite and the second earth graphite is 30 to 70% by weight and 70 to 3% by weight, respectively.
It should be 0% by weight. In any of the ground graphites, it is considered that the effect of improving the compactness becomes difficult to appear if the above range is not satisfied. Further, examples of the binder include pitches, resins, and the like, and the use of pitches is desirable in terms of uniforming open pores. The obtained kneaded material is pulverized and then classified, and is molded into a block by using only a pulverized product having a particle size of 250 μm or less. In addition, as the particle size of the pulverized product used for molding increases, an adverse effect due to an increase in the diameter of the open pores and an increase in the nonuniformity of the open pores is likely to occur.

Next, the blocked kneaded material is added to about 100
By sintering at 0 ° C. for 40 hours, a sintered carbon material (block material) is formed. The sintered carbon material thus obtained is much denser than the conventional sintered carbon material. And this sintered carbon material is not seen in the conventional manufacturing method of adjusting the specific particle size of the above-mentioned aggregate and adjusting the specific particle size of the raw material (kneaded and crushed product of the aggregate and the binder) before molding. It can be obtained by employing a control means, and a control means centering on a relatively simple adjustment operation.

Thereafter, the raw material block is roughly processed into a shape close to the intended sliding member product, and the entire raw material block is impregnated with a thermosetting resin according to a conventional method. Although there is no particular limitation on the thermosetting resin, furan resin, phenol resin and the like can be recommended because they have heat resistance, corrosion resistance and excellent impregnation. The impregnated carbon material impregnated with the thermosetting resin is subjected to heat treatment to complete the curing of the resin, so that an impregnated carbon material having a shape close to the product can be obtained. It is more dense than the material.

[0017] Finally, the finishing process for obtaining the required dimensions is performed. The texture structure of the impregnated carbon material after the processing is much denser than that of the impregnated carbon material after the conventional finishing process. As a result, mechanical strength, wear resistance, airtightness and the like can be made superior to conventional materials. Therefore, even if the impregnated carbon material after finishing is used as it is as a sliding member such as a sealing material or a bearing material of a product, it can sufficiently exhibit at least the same or higher sliding performance as compared with the conventional material. Therefore, the conventional re-impregnation work for re-densifying the structure is unnecessary,
The productivity can be improved accordingly, and the manufacturing costs required for the sealing material, bearing material and the like as products can be reduced.

Depending on the use of the sliding member, instead of impregnating the resin, a suitable metal such as lead, copper, tin, white metal or babbit metal may be impregnated to further improve heat resistance and mechanical strength. Improvements can also be made.

[0019]

Next, the present invention will be described in more detail by way of examples. (Example 1) As an aggregate, 45% by weight of a first earth graphite having a volatile content of 4% or less and an average particle size of 8 to 12 µm, a volatile material of 2% or less, and an average particle size of 6 to 10 µm. 2 earth graphite 4
A mixture containing 5% by weight and 10% by weight of scale graphite was prepared, and pitches as a binder were added thereto and kneaded with a roll. The obtained kneaded material was pulverized, adjusted for particle size by classification, and molded into a block at room temperature using a pulverized product having a particle size of 250 μm to form a block. Next, the kneaded material that has been blocked is fired at 1000 ° C. for 40 hours,
A block-shaped sintered carbon material of 20 × 60 (mm) was obtained. Next, the block sintered carbon material is roughly processed to a shape close to a product to be described later, then impregnated with a phenol resin according to a conventional method, and then subjected to a heat treatment at 200 ° C. for 2 hours to cure the phenol resin. Thus, an impregnated carbon material for sliding was obtained. Then, the obtained carbon material for sliding was subjected to a finishing process to obtain a ring-shaped mechanical seal material (product) having an outer diameter of 56 x inner diameter of 42 x thickness of 26 (mm).

With respect to the improved mechanical seal material thus obtained, the following tests were conducted in order to examine its physical properties and hermetic stability (wear resistance), and the evaluation was performed. The results of the physical properties are shown in Table 1 together with the production conditions. However, the cumulative pore distribution and the water absorption are shown in FIGS. 1 and 2, respectively, and the airtightness is shown in FIG. [Physical properties test] For the improved sliding carbon material, the bulk density, hardness, bending strength, compressive strength, elastic modulus, coefficient of thermal expansion, thermal conductivity, heat resistant temperature, cumulative pore distribution by mercury intrusion method, room temperature The water absorption by immersion in water was measured. [Test of Airtight Stability (Abrasion Resistance Performance)] A wear test was performed under the following conditions ((a) to (f)), and the airtight stability (sustainability) was evaluated by the amount of wear. (A) Sealed fluid: tap water (b) Fluid pressure: 1176 kPa (c) Contact surface pressure: 1910 kPa (d) Average peripheral speed: 8.8 m / s (e) Mate material: WC (f) Test time: 100 time

Example 2 Although the same aggregate and the same binder as in Example 1 were used, the first soil having a volatile content of 4% or less and an average particle size of 8 to 12 μm as the mixing ratio of the aggregate was used. 63% by weight of graphite, volatile matter 2% or less, average particle size 6-10
A resin-impregnated sliding carbon material according to the present invention was obtained under the same manufacturing conditions as in Example 1, except that the composition was changed to a composition in which 27% by weight of the second earth graphite of 27 μm and 10% by weight of scale graphite were blended. Was. The same test as in Example 1 was conducted on the obtained improved sliding carbon material. The results are shown in Table 1 as in Example 1.
And FIG. 1 to FIG.

Example 3 Although the same aggregate and the same binder as in Example 1 were used, the first soil having a volatile content of 4% or less and an average particle size of 8 to 12 μm as the mixing ratio of the aggregate was used. 27% by weight of graphite, volatile matter is 2% or less, average particle size is 6-10.
A resin-impregnated sliding carbon material according to the present invention was obtained under the same manufacturing conditions as in Example 1 except that the composition was changed to a composition in which 63% by weight of the second earth graphite of 63 μm and 10% by weight of scale graphite were blended. Was. The same test as in Example 1 was conducted on the obtained improved sliding carbon material. The results are shown in Table 1 as in Example 1.
And FIG. 1 to FIG.

Example 4 A block-shaped sintered carbon material was obtained using the same aggregate and binder as in Example 1 under the same manufacturing conditions, and then subjected to the same roughing. Next, antimony impregnation treatment was performed according to a conventional method to obtain a metal-impregnated sliding carbon material according to the present invention. The obtained sliding carbon material is finish-processed, and the outer shape 56 x inner diameter 42 x thickness 26 (mm)
A ring-shaped mechanical seal material (product) was obtained. The same test as in Example 1 was conducted on the obtained improved bearing material. The results are shown in Table 1 and FIGS.

Comparative Example 1 A mechanical seal material having the same dimensions as in Example 1 was obtained according to a conventional manufacturing method. That is, 50
Wt% artificial graphite and 50 wt% earth graphite (having a volatile content of 4%).
%, An average particle size of 8 to 12 μm), a phenol resin is added as a binder to the aggregate, and the mixture is kneaded, and then crushed and classified to adjust the average particle size to 300 μm. After molding and further firing at 1000 ° C., a block-shaped sintered carbon material was obtained. Next, after performing the same roughing and resin impregnation heat treatment (however, using a furan resin for the resin) as in Example 1, the sintered carbon material is further processed to a desired product shape, and the conventional carbon material is processed. To obtain a resin-impregnated carbon material for sliding. The same test as in Example 1 was performed on the obtained conventional sliding carbon material (the resin-impregnated sliding carbon material at the end of finishing). The results are shown in Table 1 and FIGS.

Comparative Example 2 The resin-impregnated sliding carbon material obtained in Comparative Example 1 was subjected to a resin-impregnation heat treatment again to obtain a re-densified structure-impregnated carbon material. The same test as in Example 1 was performed on this carbon material, and the results are shown in Table 1 and FIGS.

[0026]

[Table 1]

As is clear from Table 1 and FIGS.
All of Examples 1 to 4 satisfying the requirements of the present invention have a very high level of microstructure density as compared with Comparative Example 1 corresponding to a conventional example (sliding carbon material at the end of finishing).
As a result, it can be seen that the mechanical strength, wear resistance, airtightness and the like are far superior. Further, it can be seen that, in comparison with Comparative Example 2 corresponding to the conventional example (sliding carbon material after re-impregnation), mechanical strength, wear resistance, airtightness, and the like are more excellent.

[0028]

As described above, the sliding carbon material of the present invention is an improved resin or metal-impregnated sliding carbon material (block material), and has a conventional structure of a conventional impregnated carbon material. It is much more densified than that of, and as a result, it is excellent in mechanical strength, wear resistance, airtightness and the like. Therefore, even if the finished material of the impregnated carbon material as such a block material is used as it is as a product, there is no danger of liquid leakage at the time of sliding which was regarded as a problem in the case of the conventional material, and The reliable and stable sliding performance can be sufficiently exhibited. As a result, the conventional re-densification of the structure and the re-impregnation work for providing the necessary sliding performance are not required, thereby improving the productivity and consequently the sliding of the sealing material and bearing material as products. The manufacturing cost required for the moving member can be reduced.

Further, according to the method for manufacturing a sliding carbon material according to the present invention, the particle size adjustment of the carbonaceous raw material as the aggregate and the particle size adjustment of the raw material (the kneaded and crushed product of the carbonaceous raw material and the binder) before molding are performed. With a relatively simple adjustment work, it is possible to obtain a more dense sintered carbon material, and then continuously impregnate the dense sintered carbon material with a resin or metal, and perform the conventional re-impregnation. A resin or metal-impregnated carbonaceous material for sliding can be obtained which is denser, higher in strength and more excellent in wear resistance than the impregnated carbon material.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of examining the cumulative pore distribution of Examples 1 to 4 and Comparative Examples 1 and 2 by the mercury intrusion method.

FIG. 2 is a graph showing the results of examining the water absorption of Examples 1-4 and Comparative Examples 1-2 when immersed in normal temperature water.

FIGS. 3A and 3B are graphs showing the results of wear resistance tests on Examples 1 to 4 and Comparative Examples 1 and 2, wherein FIG. 3A is based on carbon specific wear, and FIG. It is based on the amount of wear.

Claims (6)

[Claims] 1. A bulk density of 1.80 g / cm ³ or more, an average pore radius of 0.02 μm or less, and a cumulative pore volume of 5 mm ³
/ G or less and a water absorption (normal temperature) of 1 mass% or less. 2. A kneaded product of a carbonaceous raw material and a binder is pulverized and classified, then molded, and then sequentially subjected to firing, resin or metal impregnation, to produce a resin or metal impregnated sliding carbon material. In the method, the carbonaceous raw material is a mixture of three kinds of natural graphite having different physical properties, and the kneaded material of the carbonaceous raw material and the binder is classified to have a particle size of 250.
A method for producing a carbon material for sliding, characterized in that a material having a particle size adjusted to be not more than μm is molded. 3. The three kinds of natural graphite are two kinds of earth graphite, and the other one is scaly graphite.
3. The method for producing a carbon material for sliding according to item 1. 4. The two types of earth graphite have a volatile content of 4%.
4. The method for producing a sliding carbon material according to claim 3, wherein the graphite is an earth graphite having an average particle diameter of 10 to 20 [mu] m and an earth graphite having a volatile content of 2% or less and an average particle diameter of 5 to 10 [mu] m. 5. The compounding ratio of said two types of earth graphite is as follows: volatile matter is 4% or less, earth graphite having an average particle size of 10 to 20 μm is 30 to 70% by weight, volatile matter is 2% or less, average Particle size is 5
The method for producing a sliding carbon material according to claim 4, wherein the amount of the ground graphite of 10 to 10 µm is 70 to 30% by weight. 6. The method for producing a sliding carbon material according to claim 2, wherein the binder is pitch.