JP4792843B2 - Sealing material - Google Patents

Description

  The present invention relates to a sealing material for a rotary joint (movable joint), and particularly relates to a sealing material suitable for a rotary joint for steam.

  A movable joint, that is, a so-called rotary joint, is used for feeding or discharging a fluid such as a liquid or a vapor without leaking to a rotating device. As a sealing material in such a rotary joint, a carbon molded product has been used for a long time. However, carbon molded products are hard and brittle, so if they are dropped and damaged during handling, or if fluid is supplied suddenly, they cannot withstand the impact pressure, especially when the molded products are worn down and the wall thickness is reduced. There was a drawback that it was easy. Further, when the carbon molded product is used in a dry state where no fluid flows, the temperature of the sliding surface rises due to frictional heat generation, and the wear increases accordingly. For example, a dryer part that dries paper in a papermaking machine uses 5 to 10 rolls and uses high-temperature steam as a drying heat source for the rolls, but sometimes some of them are used for paper quality adjustment. There is a case where it is used without passing steam.At that time, large wear occurs in the carbon molded product, the seal material cracks and steam leaks, the life is shortened, and production is often stopped and the seal material is used. There was a problem that productivity was reduced because a certain carbon molded product had to be replaced. More recently, the use conditions of these sealing materials have become more severe. Along with this, in order to improve the friction and wear characteristics during drying operation, change the carbon quality, change the resin material and viscosity to increase the density to fill the voids, change the impregnation method, perform metal impregnation Has been improved. For example, carbon fibers may be included as reinforcing fibers (see, for example, Patent Documents 1 and 2, etc.), three types of natural graphite having different physical properties, more preferably two types of earthy graphite, and the balance being scale-like. It has been proposed to use three types of natural graphite with graphite (see Patent Document 3). However, these methods complicate the manufacturing method, take time, and metal-impregnated carbon has high mechanical strength and wear characteristics, but is very expensive, and impregnates carbon with metal material. Therefore, the specific gravity of the molded product is large, which may adversely affect the cost and function.

Conventionally, sliding materials and bearings using condensed polycyclic polynuclear aromatic resins have also been proposed. For example, a non-asbestos friction material (see Patent Document 4) in which a hexamine cured product of a condensed polycyclic polynuclear aromatic resin in which an aromatic species is a naphthol and a hydroxyl group is modified with a metal oxide is used as a binder. Anti-oscillation consisting of a composite material in which graphite powder and fluororesin powder are dispersed in an insoluble, infusible, condensed polycyclic polynuclear aromatic resin having a basic structure in which aromatic rings containing cyclic aromatic rings are bridged via methylene Known bearings (see Patent Documents 5 and 6) are known.
JP-A-7-133163 Japanese Patent Application Laid-Open No. 2004-224982 JP-A-11-180790 JP-A-6-248254 JP-A-7-70580 JP-A-7-70585

  However, in the case of conventional carbon molded products as described above, and those using condensed polycyclic polynuclear aromatic resins, for example, in severe environments such as a rotary joint seal material for steam used in a dryer part of a papermaking machine. The properties required in the use of the are not always satisfied. Therefore, the present invention provides a rotary joint sealing material that is lighter than conventional carbon molded products, has excellent friction and wear characteristics even during dry operation without flowing fluid, and also has excellent impact resistance and handling characteristics. It is something to be done.

The rotary joint sealing material according to the present invention includes a condensed polycyclic polynuclear aromatic resin as a matrix resin, a reinforcing fiber having heat resistance and hydrolysis resistance, and a filler for improving lubricity and wear resistance. It is characterized by comprising lamp black as the filler .

  As the reinforcing fiber, polyphenylene sulfide fiber or carbon fiber is preferable, and polyphenylene sulfide fiber is particularly preferable.

  Moreover, a fluororesin and / or a silicon compound can also be used as the filler.

  In a preferred embodiment of the sealing material of the present invention, the condensed polycyclic polynuclear aromatic resin is 35 to 60% by weight, the polyphenylene sulfide fiber is 15 to 60% by weight, the carbon fiber is 4 to 30% by weight, and the lamp black is 10 to 40% by weight. It consists of a resin composition containing. In a further preferred embodiment, it comprises a resin composition containing 5 to 30% by weight of a silicon compound in addition to the above.

  In the sealing material for rotary joint according to the present invention, the condensed polycyclic polynuclear aromatic resin as the matrix resin has not only excellent heat resistance but also high hydrolysis resistance against high-temperature steam. In addition, since it contains reinforcing fibers having heat resistance and hydrolysis resistance, it is suitable as a sealing material for a rotary joint for steam. Furthermore, since it contains a filler for improving lubricity and wear resistance, it has excellent wear characteristics during drying operation, and is suitable as a sealing material for a rotary joint in a dry part of a papermaking machine, for example.

  In the resin composition constituting the sealing material of the present invention, the condensed polycyclic polynuclear aromatic resin (hereinafter referred to as “COPNA resin”), which is a matrix, has not only heat resistance but also high hydrolysis resistance against high-temperature steam. It has sex. As the matrix of the sealing material, polyethersulfone resin (PES), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), etc. are used, but the COPNA resin, which is a thermosetting resin, is used at a high temperature. Because of its high physical properties, it has excellent load capacity. Examples of the COPNA resin include SK resin QH-B01 manufactured by Air Water Chemical Co., Ltd. As content of COPNA in a resin composition, the range of 35 to 60 weight% is preferable. As the content of the COPNA resin increases, the compressive strength of the material increases, the load capacity increases, and the wear resistance improves. When the content of the COPNA resin is less than 35% by weight, the adhesion with reinforcing fibers and other fillers is lowered, and as a result, the wear resistance is also lowered. On the other hand, if the content of the COPNA resin exceeds 60% by weight, the adhesion to the reinforcing fiber is improved, but the amount of the reinforcing fiber and other fillers is reduced accordingly. As a result, the wear resistance is also lowered.

  As the reinforcing fiber having heat resistance and hydrolysis resistance in the sealing material, polyphenylene sulfide (hereinafter referred to as PPS) fiber or carbon fiber is preferably used.

The PPS fiber content in the composition is preferably in the range of 15 to 60% by weight, and more preferably 30% by weight or less. When the content of the PPS fiber is less than 15% by weight, the intended reinforcing effect may not be sufficiently exhibited. Further, when the PPS fiber exceeds 30% by weight, the friction and wear characteristics tend to be reduced, and the friction coefficient is as high as 0.36 immediately after the start of the test, and the amount of wear is 23 hours as compared with the case where the content is 30% by weight or less. Later, a test result of 1.4 times was obtained (no lubrication by a pin-on-disk type friction and wear tester, contact pressure of 0.5 MPa, sliding speed of 1.2 m / second, temperature of 180 °, counterpart chrome plating surface). Moreover, since PPS fiber is a chemically very stable fiber, its adhesiveness with the COPNA resin which is a matrix resin is not so good. For this reason, when content exceeds 60 weight%, there exists a tendency for the compressive strength of a molded article to fall conversely.
The fineness of the PPS fiber used for the sealing material of the present invention is about 1.0 to 3.0 dtex, and the length is preferably 1 to 10 mm.

The carbon fiber may be used in combination with the PPS fiber as a reinforcing fiber, or may be used alone. The content of carbon fiber in the composition when used alone is preferably 15 to 40% by weight, and when used in combination with PPS fiber, it is preferably within the range of 4 to 30% by weight. If the carbon fiber is less than 4% by weight, the added effect does not appear. If the carbon fiber exceeds 40% by weight, the content of the matrix COPMA resin is reduced, the adhesiveness is lowered, and the mechanical strength and frictional wear characteristics are lowered. Carbon fiber has high heat resistance, does not cause hydrolysis, and has a large elastic modulus and high strength. Therefore, it contributes to improving the impact resistance, wear characteristics, and load capacity of the sealing material, and it can also be used for sliding in steam. It has the effect of reducing the coefficient of friction by movement.
The fiber diameter of the carbon fiber used for the sealing material of the present invention is preferably 5 to 10 μm and the length is 30 to 300 μm.

  The filler for improving lubricity and wear resistance is not particularly limited, and examples thereof include carbon-based fillers, fluororesins such as PTFE, silicon compounds, solid lubricants, inorganic fillers, Among these, a carbon-type filler, a fluororesin, and a silicon compound are preferable. Furthermore, as the carbon-based filler, various types such as natural graphite and carbon can be used. Among these, lamp black is preferable as the carbon-based filler. Lamp black is a kind of so-called carbon, but in the present invention, among the carbons called carbon black, lamp black exhibits extremely low friction and low wear especially against sliding in water vapor. I found it. Among carbon-based fillers, natural graphite and artificial graphite, for example, are excellent in the effect of improving frictional wear at high temperature drying, but show a friction coefficient seven times that of carbon molded products in water vapor, and the amount of wear. There is a tendency to increase. For example, there are activated carbon, carbon produced by carbonizing phenol resin, carbon produced from coke, etc., all of which have advantages and disadvantages. On the other hand, lamp black exhibits frictional wear characteristics that are not inferior to carbon molded products even in the case of rotary joints used in both steam and dry atmospheres. Since lamp black has a very small particle size of 0.1 to 0.2 μm and a large surface area, when it is added in a large amount to the composition, the binding force of the matrix resin is lost, and the strength tends to decrease and the wear amount tends to increase. There is. For this reason, it is preferable that the upper limit of the addition amount in a composition shall be 40 weight%. On the other hand, if the amount of lamp black added is too small, a low coefficient of friction in water vapor cannot be secured. Therefore, the preferable addition amount of lamp black is in the range of 10 to 40% by weight in the resin composition.

  The silicon compound is a silicone-impregnated filler containing silica and silicone oil, and the present inventor has confirmed that the silicon compound has a low coefficient of friction at an early stage without affecting the wear of the sealing material in water vapor. It has also been found that the friction coefficient during drying and the amount of wear can be reduced. The content of the silicon compound in the composition is 5 to 30% by weight. When the silicon compound is less than 5% by weight, the effect of addition is not seen, and when it exceeds 30% by weight, the contents of the matrix, reinforcing fibers, other fillers, etc. are relatively lowered, and as a result There is a possibility that the heat resistance and the frictional wear resistance property during drying may not be exhibited.

  From the above, preferable blending of the resin composition constituting the sealing material of the present invention is 35 to 60% by weight of condensed polycyclic polynuclear aromatic resin, 15 to 60% by weight of polyphenylene sulfide fiber, and 4 to 30% by weight of carbon fiber. % And lamp black in the range of 10 to 40% by weight, and further, a compound containing silicon compound in the range of 5 to 30% by weight is preferable.

  The method for producing the sealing material of the present invention is not particularly limited. For example, first, a resin composition as a molding material is charged with a COPNA resin serving as a matrix, reinforcing fibers, and a filler in a Henschel mixer, and stirred and mixed at 2100 rpm for 1 minute. The obtained mixture is preheated with a hot air dryer at 100 ° C. for 80 minutes to obtain a molding material. As a method of molding the sealing material of the present invention from this molding material, a necessary amount of the molding material is weighed, put into a mold heated to 135 ° C., held for 40 minutes, and then heated to 170 ° C. Hold for 120 minutes, cool and remove from mold at mold temperature 100 ° C. For example, the molding pressure is maintained at 10 MPa for 20 minutes and then at 30 MPa for 220 minutes.

  As described above, it is possible to obtain a molding material for a sealing material that has friction and wear characteristics that are not inferior to those of conventional carbon molded products, and that is superior in impact resistance and handling properties compared to carbon molded products.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. Prior to the description of the examples, the molding materials and evaluation methods used are described below.

(1) Molding material [Matrix resin]
COPNA resin: Air Water Chemical Co., Ltd. SK Resin QHB-01
Phenol resin: Sumitomo Bakelite Co., Ltd. PR50965
[Reinforcing fiber]
PPS fiber: Toray Industries, Inc. PPS fiber "Torcon" S101 (fineness: 1.0 dtex, fiber length: 6 mm)
Carbon fiber: Toray Industries, Inc. “Torayca” MLD300 (fiber diameter: 7 μm, length: 130 μm)
[Carbon filler]
Graphite 1 (natural graphite): Chuetsu Graphite Industry Co., Ltd. CPB3 (15 μm)
Graphite 2 (artificial graphite): SCC Co., Ltd. SGP3 (3 μm)
Graphite 3 (artificial graphite): ESC Corporation SGP25 (25 μm)
Carbon 1: SCC Co., Ltd. SCN40 (carbon particle size 40μm)
Carbon 2: SCC Co., Ltd. SCN5 (carbon particle size 5μm)
Carbon 3: Kanebo Corporation Bell Pearl C-800
Carbon 4: Fukusen Kasei Co., Ltd. LAMP BLACK CARBON
Carbon 5: Tokai Carbon Co., Ltd. Hydrophilic carbon black HA3
[Solid lubricant]
PTFE: Kitamura KTL620
(Other fillers)
Silicone compound: Toray Dow Corning Silicone Co., Ltd. “Trefill” F-201

(2) Evaluation method The steam resistance of the sealing material was examined by changes in compressive strength and frictional wear characteristics when treated at an atmospheric temperature of 150 ° C and a relative humidity of 100% for 100 hours.

(Test method)
a) Compressive strength: measured in accordance with JIS K6911.
b) Bending strength: measured in accordance with JIS K6911.
c) Flexural modulus: measured in accordance with JIS K6911.
d) Izod impact strength: measured in accordance with JIS K6911.
e) Friction and abrasion test: as follows.
(I) Non-lubricating tester: Pin-on-disk friction and wear tester Sliding speed: 1.2 m / sec Contact pressure: 0.5 MPa
Mating material: Hard chrome plating Lubrication: No lubrication Mating material temperature: 180 ° C
Test time: 20 hours (ii) Lubrication (in steam)
Testing machine: Pin-on-disk friction and wear testing machine Sliding speed: 1.2 m / sec Contact pressure: 0.5 MPa
Mating material: Hard chrome plating Lubrication: 120 ° C steam (near the steam outlet)
Mating material temperature: 180 ° C
Test time: 8 hours

(Examples 1-2, Comparative Examples 1-2)
The materials shown in Table 1 were put into a Henschel mixer, stirred and mixed at 2100 rpm for 1 minute, and the mixture was preheated at 100 ° C. for 80 minutes with a hot air dryer to obtain a molding material. The molding material was put into a mold heated to 135 ° C., held for 40 minutes, heated to 170 ° C., held for 120 minutes, cooled, and taken out from the mold at a mold temperature of 100 ° C. Example 1 The sealing material of -2 and the comparative example 1 was obtained. The molding pressure was held at 10 MPa for 20 minutes and then held at 30 MPa for 220 minutes. As Comparative Example 2, a carbon molded product was used. Table 1 shows the evaluation results of the obtained sealing materials of Examples 1-2 and Comparative Examples 1-2.

  As is apparent from Table 1, the sealing material of the present invention has no change in compressive strength before and after the steam treatment like the phenol resin sealing material shown in Comparative Example 1. Further, compared to the conventional carbon molded product shown in Comparative Example 2, the Izod impact strength is very high.

(Examples 3 to 13, Comparative Example 3)
A sealing material was obtained in the same manner as in Example 1 using the materials having the formulations shown in Tables 2-1 and 2-2. The evaluation results of the obtained sealing material are shown in Tables 2-1 and 2-2. Table 2-1 also shows the evaluation results of the sealing material of Example 2.

As apparent from Tables 2-1 and 2-2, COPNA resin is used as a matrix resin, PPS fibers and / or carbon fibers are contained as reinforcing fibers, and carbon-based fillers such as graphite and carbon, and fluororesins ( The sealing material of the present invention containing a filler such as PTFE) or silicon compound is excellent in friction and wear characteristics both in the absence of lubrication (when dry) and during lubrication (in steam). Further, when carbon is used as a filler, there is little difference in friction and wear characteristics between no lubrication (drying) and lubrication (in steam). In addition, when lamp black is used as the carbon-based filler, the friction and wear characteristics of lubrication (in steam) are excellent. In contrast, the sealing material of Comparative Example 3 that uses COPNA resin as a matrix resin and PPS fibers as reinforcing fibers but does not contain a filler has a significantly reduced frictional wear characteristic in steam as compared with drying.

Claims (5)

A resin composition comprising a condensed polycyclic polynuclear aromatic resin as a matrix resin, a reinforcing fiber having heat resistance and hydrolysis resistance, and a filler for improving lubricity and wear resistance , A rotary joint sealing material comprising lamp black as a filler .   The sealing material according to claim 1, wherein the reinforcing fiber is polyphenylene sulfide fiber or carbon fiber. The sealing material according to claim 1 or 2 , wherein the filler contains a fluororesin and / or a silicon compound. Condensed polycyclic polynuclear aromatic resin 35 to 60 wt%, polyphenylene sulfide fibers 15-60 wt%, comprising a resin composition containing carbon fibers 4 to 30% by weight and the lamp black 10 to 40 wt% of claim 1 Seal material. The sealing material according to claim 4 , wherein the resin composition further contains 5 to 30% by weight of a silicon compound.