JP6599681B2 - Packing - Google Patents

Description

  The present invention relates to an annular packing formed of a base fabric in which a base material is embedded in a rubber composition, and in particular, a packing having a substantially V-shaped or U-shaped cross section, for example, disposed between a piston and a cylinder. About. The annular packing is used in a wide range of industrial fields such as a power plant, a chemical industry plant, a tire industry, various devices, and seals of sliding parts of the apparatus.

  Conventionally, packing is made by laminating a plurality of sheets impregnated with a rubber composition on a cloth material made of braided fibers of asbestos, cotton, glass, etc., and vulcanized and molded into a predetermined shape, such as industrial equipment, plants, etc. Used in the field.

  Packing using a cloth material of cotton or glass fiber is inferior in resistance to high temperature steam when used in an environment exposed to high temperature steam, and cannot be used for a long time. Therefore, in an environment exposed to steam at a high temperature, a packing formed by laminating a rubber layer reinforced with an asbestos cloth material has been used. However, asbestos is harmful to the human body, so its use tends to be regulated worldwide, and the development of alternative products is desired.

  In addition, when carbon fiber cloth is used as a material, heat resistance is improved, but the carbon cloth is rigid, difficult to braze to a predetermined shape, and delamination occurs. .

  Moreover, in the case of a packing formed with a nitrile rubber layer reinforced with a cotton cloth, the heat resistance is low and it cannot be used at high temperatures. Further, in the case of a packing formed with a fluorine rubber layer reinforced with a cotton cloth, the heat resistance is improved, but the wear resistance is inferior. In particular, when these packings are used for water / glycol hydraulic fluid, the hydraulic fluid may leak due to low wear resistance.

  In Japanese Patent No. 4712486 (Patent Document 1), after a packing forming tape obtained by cutting a carbon cloth by a specific method is laminated on a mold, it is easily shaped into a predetermined shape and vulcanized. A method of manufacturing a packing is disclosed.

  In Japanese Patent Publication No. 42-20943 (Patent Document 2), a cloth such as cotton and rayon is impregnated with a non-cured rubber, and the sheet is spirally wound to form a cylindrical shape. A packing ring is disclosed which is cut into a length and bent into one U-shape by bending one circumferential end of a cylinder meter inward.

  Further, Japanese Utility Model Publication No. 59-174456 (Patent Document 3) discloses an annular packing having a core portion made of a fiber impregnated with a rubber-like elastic material, and an outer peripheral portion of the core portion impregnated with a resin material. What consists of the base fabric which was made is disclosed.

  However, in the packing rings described in Patent Document 2 and Patent Document 3, since the rubber composition constituting the base fabric uses a general-purpose rubber, the sealing property and the seal life are inferior, and the heat resistance is poor and the heat and steam environment is poor. There is a problem that it is not suitable for use below.

Japanese Patent No. 4712486 Japanese Patent Publication No.42-20943 Japanese Utility Model Publication No.59-174456

  The present invention provides a packing that can be used in a high-temperature / steam environment, is excellent in wear resistance, sealing performance, and sealing life, and that solves the problem of environmental contamination when using asbestos.

  Further, in the embodiment of the present invention, it is possible to preform the desired shape by imparting flexibility to the base fabric for forming the packing. Then, after the pre-molding, a method for producing a packing having excellent appearance and physical properties after vulcanization by maintaining the molded shape by reducing the restoring force even if the molding pressure is released is provided.

  The present invention is an annular packing obtained by molding and cross-linking a tape-like base fabric in which a base material is embedded in a rubber composition, and the rubber composition contains 60 mass% of hydrogenated nitrile rubber as a rubber component. Pertaining to packing containing more than%.

  Here, the hydrogenated nitrile rubber preferably has an acrylonitrile content of 25% by mass to 50% by mass. And the elongation of the base fabric after crosslinking can effectively exhibit the required characteristics of the packing in the range of 35 to 60%. Moreover, it is desirable that the base material constituting the base fabric is formed of a weave fabric made of warp and weft yarns of aramid fibers or a plain fabric of aramid fibers.

  The packing of the present invention is preferably formed of a laminate of a plurality of tape-like base fabrics, and the base material yarns preferably cross each other between the laminates. The cross section of the packing is preferably V-shaped or U-shaped.

Furthermore, the present invention is a method for producing a packing using an annular mold,
(A) impregnating the base material with a hydrogenated nitrile rubber composition solution, and preparing a base fabric in which the base material is embedded in the rubber composition;
(B) a step of preparing a plurality of tape-shaped base fabrics obtained by cutting the base fabric into biases with a predetermined dimension;
(C) a step of sequentially arranging the tape-like base fabric on the surface of the annular mold along the entire circumference thereof;
(D) pressurizing the tape-shaped base fabric in the mold direction, and bringing the tape-shaped base fabric into close contact with each other to form a preform, and (e) pressurizing the preform. The present invention relates to a packing manufacturing method comprising a step of heating and crosslinking.

  Since the packing of the present invention is reinforced by embedding a base material in a rubber composition mainly composed of hydrogenated nitrile rubber, the moldability is improved by appropriate flexibility of the base fabric, and further, heat resistance and steam resistance at high temperatures. The sealability and seal life as well as the performance are improved.

It is sectional drawing of the hydraulic piston cylinder which shows the arrangement | positioning state of an annular packing. It is sectional drawing cut | disconnected in the radial direction of the annular packing. It is a perspective view of the packing shape | molded by the cyclic | annular metal mold | die. It is AA sectional drawing in FIG. It is the schematic of the elongate base fabric by which the base material of the weave fabric was embed | buried under the rubber composition. It is sectional drawing of the base fabric by which the bamboo woven fabric was embed | buried under the rubber composition. It is a cross-sectional perspective view of the molding die of packing. It is a cross-sectional perspective view of the molding die of packing. It is a cross-sectional perspective view of the molding die of packing.

  The present invention is an annular packing obtained by molding and crosslinking a tape-like base fabric in which the base fabric is embedded in a rubber composition, and the rubber composition contains 60 hydrogenated nitrile rubber as a rubber component. Contains at least mass%.

  The packing of the present invention is, for example, in the sectional view of the hydraulic piston cylinder 1 shown in FIG. 1, and a plurality of annular packings 4 are disposed between the cylinder 2 and the piston 3. In FIG. 1, four annular packings 4 are arranged between the concave adapter 5 and the convex adapter 6, and a total of 16 on the left and right. The annular packing of the present invention has sufficient durability at high temperature and high humidity when the piston in the cylinder is operated, and maintains high sealing performance even after a long working distance.

<Packing shape>
In FIG. 2, the cross-sectional shape which cut | disconnected the annular packing 41 in the diameter direction is shown. The cross section of the packing has a substantially V shape, and is formed of a laminate of two outer base cloths 4a disposed outside the packing and an inner base cloth 4b disposed inside the packing.

  The annular packing 41 having a substantially V-shaped cross section formed by laminating the base fabric is formed with, for example, an inner diameter R1 of 30 mm to 500 mm, a height h of 2 to 20 mm, and a width W of 5 to 30 mm.

  The cross-sectional shape of the packing 41 can be a substantially U shape or a substantially circular shape in addition to the substantially V shape shown in FIG. These cross-sectional packings are manufactured by forming a tape on a corresponding cross-sectional forming mold and cross-linking. The cross-sectional shape of the packing of the present invention is not particularly limited, but corresponds to the cross-sectional shape of the molding die, for example, a triangle 10A with a convex section as shown in FIG. 7, and a cross-sectional shape as shown in FIG. 10B, or a C-shaped cross section (10C) as shown in FIG.

<Base material>
In the present invention, the base fabric is produced by embedding a base material in a rubber composition. Here, the base material may be a woven fabric such as a sand woven fabric, a plain woven fabric, a twill woven fabric, a knitted fabric, a non-woven fabric, or the like. Also, thick fabrics (combined yarns, thick fabrics using twisted yarns), satin fabrics (a complete structure including at least 5 warp and weft yarns. A structure in which the number of jumps is 1 or more can also be suitably used. In addition to organic fibers such as aramid, polyester, nylon, rayon and cotton, inorganic fibers such as carbon fibers and glass fibers can be used as the fibers. In particular, an aramid fiber is suitable from the viewpoint of heat resistance performance and sealing performance.

FIG. 5 is a schematic view of a long base fabric in which a base material of a braided fabric is embedded in a rubber composition. Here, the thickness before the rubber composition is impregnated into the woven fabric or the knitted fabric as the base material is, for example, 0.2 mm to 0.80 mm, and the weight per unit area before the base material rubber composition is impregnated is For example, it is 100 to 300 g / m ² .

  The woven fabric has a woven density represented by the number of fibers used within a width of 1 cm in the vertical and horizontal directions, for example, 3 to 15 fibers / cm, preferably 4 to 10 fibers / cm. In the case of a weave fabric, flat and thin base material thickness, unlike a three-dimensional and thick basket weave, the weave density is small, the rubber composition is easily impregnated with the fabric, and the interfacial delamination between rubber and fibers It hardly occurs, and the molded packing has excellent surface smoothness.

  In the present invention, the flexibility of the base fabric is maintained by using fine fibers as the base material, and the base material and rubber in the base fabric obtained by impregnating and adhering the rubber composition to the base material are unlikely to occur. It is excellent in workability to a desired sealing material and excellent in surface smoothness of the sealing material after molding. When the fiber diameter is too large or the weave density is high, the base fabric becomes stiff and the moldability on the mold becomes difficult.

<Base fabric>
The base fabric is manufactured by embedding the base material in a rubber composition or impregnating the base material with a solution of the rubber composition. FIG. 6 shows a cross-sectional view of a base fabric in which a braided fabric is embedded in a rubber composition. In the figure, the warp yarns 13 are arranged at regular intervals in the longitudinal direction, and fine weft yarns 14 are alternately arranged above and below the warp yarns 13 to maintain the mutual positional relationship between the warp yarns 13. In the base fabric 11, a base material composed of warp and weft is embedded in the rubber composition 12.

  Content of the rubber composition in a base fabric is 40-80 mass%, Preferably it is the range of 50-70 mass%. Maintains the physical properties required for packing, such as moderate elasticity and mutual adhesion of the base fabric during molding, and allows the laminate of the base material before crosslinking to be brazed into the desired shape, preliminarily under pressure The content of the rubber composition is adjusted so that it can be molded into a molded body.

  If the content of the rubber composition in the base fabric is small, the rigid physical properties of the sheet or its laminate are too bad for the entire packing, and it is difficult to obtain a packing having an appropriate elasticity as a sealing material. Peeling easily occurs. Further, in the manufacturing process, it is difficult to braze and the workability to a preformed body and the like is also deteriorated. On the other hand, if the content of the rubber composition in the base fabric exceeds the above range, the influence of the flexible physical properties of the rubber component on the physical properties of the entire packing is large, and the effect of reinforcing the packing by filling the base material is large. It becomes inadequate and it becomes difficult to obtain a so-called laminate molding packing of a strong base fabric.

(Tape-like base fabric)
The tape-shaped base fabric 11 is manufactured by cutting a long base fabric, in which a base material is embedded in a rubber composition, into a bias at a predetermined angle and a predetermined width in the longitudinal direction. The The width m of the tape-shaped base fabric is, for example, 10 to 30 mm, and the bias angle θ is usually set in a range of 30 ° to 60 °.

(Elongation rate of base fabric)
The elongation of the tape-like base fabric is desirably in the range of 35 to 60%. Within this range, the base fabric formed on the packing is given flexibility and can be preformed into a desired shape. Then, after the pre-molding, even if the molding pressure is released, the restoring force is reduced to maintain the molded shape, and after vulcanization, a packing excellent in wear resistance and seal resistance can be obtained.

<Rubber composition>
The rubber composition for embedding the base material is produced, for example, by dissolving a rubber composition such as hydrogenated nitrile rubber or nitrile rubber in a solvent. As the solvent, for example, rubber solvents such as acetone, toluene, and methyl isobutyl ketone (MIBK) can be used.

  The compounding ratio of the rubber component in the rubber composition and the solvent is not particularly limited. For example, in 100 parts by weight of the rubber composition, the rubber component is in an amount of 15 to 25 parts by weight, and the solvent is the remaining amount, for example, , 85-75 parts by weight.

  In the present invention, the rubber component contains 60% by mass or more of hydrogenated nitrile rubber (hereinafter also referred to as “H-NBR”). Here, in the hydrogenated nitrile rubber, the acrylonitrile content is in the range of 25% by mass to 50% by mass.

  The hydrogenated nitrile rubber is a polymer obtained by hydrogenating the double bond portion of the butadiene unit of the nitrile rubber, and heat resistance and aging resistance are improved by hydrogenation. Here, a hydrogenation rate of 60 to 98% is commercially available, and can be suitably used.

  Various types of hydrogenated nitrile rubber (H-NBR) can be appropriately employed in consideration of the moldability required for the rubber composition, the mechanical properties required for the rubber cross-linked product, light transmittance, and the like. . Specifically, the brand name made by Nippon Zeon Co., Ltd .: ZETPOL series, the brand name made by Bayer Corporation: Therban series, etc. are exemplified.

  In the present invention, these hydrogenated nitrile rubbers may be used alone, or two or more kinds of H-NBR may be blended and used for the purpose of adjusting Mooney viscosity, vulcanization speed, oil amount and the like. .

  It is also possible to blend H-NBR with other rubber components. Other rubber components include, for example, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), nitrile rubber (NBR; acrylonitrile butadiene rubber), butyl rubber (IIR), fluoro rubber (FKM), silicone rubber, and the like. Can be used. Of these, nitrile rubber (NBR), EPDM, FKM and the like are preferable from the viewpoint of sealing properties. The rubber component may consist of only one kind or may contain two or more kinds.

When these rubber components are used, they are blended in an amount of less than 40% by mass of the entire rubber component.
<Crosslinking agent>
In the present invention, sulfur, an organic sulfur compound, disulfide, an organic peroxide, or the like is used as a crosslinking agent. Examples of organic peroxides employed in EPDM and H-NBR include 2,5-dimethyl-2,5-di-t-butyl-peroxyhexane-3, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butyl-peroxyhexane, t-butylcumyl peroxide, 1,3-bis (t-butylperoxy-isopropyl) benzene, dicumyl peroxide, 4, 4-di-t-butylperoxy-butylvalerate, 2,2-di-t-butylperoxy-butane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, di -Benzoyl peroxide, bis (o-methylbenzoyl) peroxide, bis (p-methylbenzoyl) peroxide, t-butyl peroxybenzylate, etc. It is exemplified.

  A crosslinking agent is mix | blended in the range of 0.5-5 mass parts with respect to 100 mass parts of rubber components by 1 type or several types.

<Manufacture of packing>
The packing of the present invention is manufactured by the following process using an annular mold.
(A) A step of preparing a base fabric in which a base material is embedded in a rubber composition by impregnating the base material with a solution of the hydrogenated nitrile rubber composition.
(B) A step of preparing a plurality of tape-shaped base fabrics obtained by cutting the base fabric into biases with predetermined dimensions.
(C) A step of sequentially arranging the tape-like base fabric on the surface of the annular mold along the circumferential direction thereof.
(D) A step of pressurizing the base fabric of the tape in the mold direction so that the tape-shaped base fabrics are in close contact with each other to form a preform.
(E) A step of pressing and heating the preform to crosslink.

  Hereinafter, a method for producing an annular packing according to the present invention will be described with reference to the drawings. FIG. 3 is a perspective view of a packing formed in an annular mold. FIG. 4 is a cross-sectional view taken along the line AA in FIG.

<Process for preparing tape-shaped base fabric>
In FIG. 5, a tape-shaped base fabric 11 is obtained by bias-cutting a long base fabric 150 at a predetermined angle θ (X direction) in the length direction of the base fabric, and the plane is a parallelogram tape-shaped base fabric. 11 multiple sheets are produced.

  FIG. 5 is a schematic view of a long base fabric 150 in which a base material is embedded in a rubber composition, and FIG. 6 is a cross-sectional view of the base fabric 150. In FIG. 5 and FIG. 6, a long base cloth 150 extending left and right toward the paper surface is cut by paralleling the bias angle θ with respect to the longitudinal direction (lateral direction toward the paper surface) to 30 ° to 60 °, for example. A quadrilateral tape-like base fabric 11 is obtained.

  In addition, the weft fabric of the warp 13 and the weft 14 is used for the base fabric 150 in FIG. 5, the warp 13 is arranged in the longitudinal direction of the base material, and the weft 14 is woven so as to be arranged in the base material width direction. Has been.

  The dimensions of the tape-shaped base cloth 11 vary depending on the inner and outer diameters of the piston shaft and the like to be sealed, the use site, the required groove depth, the packing dimensions, and the like, and are not generally determined. The width m is 10 mm to 30 mm. The thickness of the base material before impregnation with the rubber composition is 0.2 mm to 0.8 mm. The length of the base fabric is not particularly limited.

The basis weight of the base material before impregnation with the rubber composition is 100 to 300 g / m ² , preferably 150 to 250 g / m ² . When the weight per unit area is larger than the above range, the weight per unit area is too large, and the surface appearance of the packing tends to be poor and the elasticity tends to be poor.

<Step of preforming>
3 and 4, a tape-like base cloth 11 having a parallelogram-like plane cut from the base cloth with a bias is sequentially arranged on the outer peripheral surface of the molding die 10 in a spiral manner along the circumferential direction. The tape-shaped base fabric 11 arranged and laminated in the circumferential direction of the molding die 10 is pressed along the surface shape of the die or fitted to an outer die to perform preliminary molding. At this time, an adhesive can be used to temporarily attach the tape-shaped base cloth to the mold 10 and to bring the tape-shaped base cloth 11 into close contact with each other. Here, as the adhesive, for example, a paste having the same composition as the rubber composition used for packing can be used.

  In the present invention, one or more tape-shaped base fabrics 11 are pressed from the outside on the side of the molding die 10 by pressing a preform formed by laminating the surface of the die with an adhesive if necessary. The base fabrics 11 are brought into close contact with each other.

  At the time of this pressurization, an outer mold that can be molded into a desired shape by sandwiching the preformed body may be used in combination with the molding mold 10. The cross-sectional shape of the outer mold is a void portion shape such as a triangle with a circular cross-section, a cross-section with a concave section, and a cross-section with a C-shape so as to match the shape of the outer peripheral surface of the ring-shaped mold 10. It is desirable.

  In the present invention, the molding die 10 is used for molding, but the molding die 10 shown in FIG. 4 has a convex portion G ′ corresponding to the groove G of the packing in FIG. The molding die 10 has a triangular cross section, and the planar shape is annular. By using this molding die 10, it is possible to reliably and easily perform molding into a desired shape.

<Crosslinking process>
FIG. 2 shows a packing 41 having a substantially V-shaped cross-section, which is obtained by crosslinking and molding a preformed body obtained by molding and heating it in a mold under pressure. Crosslinking / molding conditions differ depending on the type of rubber component of the rubber composition and are not determined unconditionally. For example, in a composition containing 100 parts of hydrogenated nitrile rubber, it is held at a temperature of 120 to 170 ° C. for 1 to 40 minutes. The The cross-linked and molded packing 41 has excellent external surface smoothness, excellent tensile strength, flexibility for bending, and does not cause delamination during use, and can withstand long-term use. ing.

<Manufacture of product packing>
When the packing 41 of the present invention is formed of a laminated body, the warp (or weft) of the base material is a circle of the annular member at any part of the outer surface of the annular member (for example, the rotating shaft) to be sealed. They are arranged so as to cross the bias on the same plane as the circumferential direction.

  In the packing manufacturing method of the present invention, the fibers constituting the bias-cut tape-shaped base fabric are arranged in a bias between the layers of the laminate, so that the preforming of the packing is performed in comparison with the conventional base fiber. Easy to mold and efficient. In addition, peeling of the base fiber of the packing is prevented, and the balance of appearance, tensile strength, bending and the like is excellent.

The annular packing of the examples and comparative examples and the manufacturing method thereof will be specifically described.
<Base material>
The base materials used in the examples and comparative examples shown in Table 2 are as follows.
(1) Base material (cotton)
Thick weave, warp density: 10 / cm, weft density: 10 / cm, substrate thickness: 0.7 mm,
Weight per unit area: 61 g / m ²
(2) Base material (aramid 1)
Plain weave, warp density: 12 / cm, weft density: 12 / cm, substrate thickness: 0.42 mm,
Weight per unit area: 66 g / m ²
(3) Base material (aramid 2)
Satin weave, warp density: 29 / cm, weft density: 20 / cm, substrate thickness: 0.65 mm, basis weight: 66 g / m ²
<Production of base fabric>
A base fabric was produced by applying the impregnating solutions of the rubber compositions of Formulation A to Formulation C shown in Table 1 to various substrates and drying them at room temperature. Here, the mass of the rubber composition is 66% by mass of the mass of the base fabric.

(Rubber impregnation solution)
The rubber composition of Formulation A to Formulation C shown in Table 1 and the solvent (MIBK: methyl isobutyl ketone) were mixed in a solvent (78 mass%) mass with respect to mass parts of the rubber composition (solid content: 22 mass%). Prepared by mixing in parts.

(Production of tape-shaped base fabric)
Next, the long base fabric is cut at an angle of about 45 ° with respect to the length direction (θ = 45 ° in FIG. 5) at intervals of 20 mm to obtain a tape-shaped base fabric having a width of 20 mm. It was.

(Create packing)
Next, as shown in FIG. 3 and FIG. 4, the tape-shaped base fabric is arranged in a circle so that the end cut by the bias coincides with the circumferential direction of the upper surface of the molding die 10, and the lake agent ( Composition: the same as the rubber impregnating solution) was laminated and laminated to obtain a preform molded with a substantially V-shaped cross section.

  Next, the molded preform was set in a heat and pressure molding mold and pressed at a temperature of 160 ° C. for about 25 minutes at a pressure of 10 MPa to produce a crosslinked and molded packing. With reference to FIG. 2, the created packing had a height h of 8.5 mm, an inner diameter R1 of 98.7 mm, and a width W of 11.3 mm.

<Method for evaluating physical properties>
The material evaluation and operation test evaluation of the packing were carried out by the following methods, and the results are shown in Table 2. The evaluation is 1 to 5 points, and 5 points is the best.

(1) Heat resistance Material evaluation and operation tests were comprehensively evaluated based on the respective results.

(A) Material evaluation test A dumbbell test piece having a length of 100 mm and a thickness of 2 to 3 mm was prepared using a base fabric, and a deterioration test was performed according to JIS B2403 in an environment of 120 to 160 ° C. The test piece was immersed in MAX 1,000 Hr in hydraulic oil. The degree of material deterioration was evaluated by measuring the characteristics of hardness, tensile strength, elongation, and volume.

(B) Operation test The packing was subjected to an operation test at an environmental temperature of 100 ° C. Here, the operating conditions are a load pressure of 21 MPa, an operating speed of about 200 mm / sec, and a stroke of 50 mm. In this test, a sample for evaluation is assembled in the rod packing part of a penetrating rod type test device (as shown in Fig. 1 with JIS B2409), and the rod is directly driven while applying pressure between both packings with a hydraulic source to perform an operation test. It is a test to be performed. Durability was evaluated by measuring the amount of leakage (cc / 100m) during operation of 0 to 100 km.

(2) Steam resistance A dumbbell test piece having a length of 100 mm and a thickness of 2 to 3 mm was prepared using a base fabric, and a deterioration test was conducted according to JIS · K6258 in an environment of 120 to 180 ° C. The degree of material deterioration was evaluated by measuring the characteristics of hardness, tensile strength, elongation, and volume.

(3) Abrasion resistance A comprehensive evaluation of the operation test and the cylinder operation durability test was conducted.

(A) Operation test An operation test was conducted at an environmental temperature of 100 ° C. The operating conditions are a load pressure of 21 MPa, an operating speed of about 200 mm / sec, a stroke of 50 mm, and the hydraulic oil is a water-glycol hydraulic oil. In this test, a sample for evaluation is assembled in the rod packing part of a penetration rod type test device (as shown in Fig. 1 with JIS B2409), and the rod is directly driven while applying pressure between both packings with a hydraulic source to perform an operation test. It is a test to be performed. Abrasion resistance was evaluated from the dimensional change of the packing and the appearance damage.

(B) Cylinder operation endurance test The relief pressure was 21 MPa, the oil temperature was 60 ° C., the operation speed was about 100 mm / sec, the stroke was 250 mm, the operation distance was 1,000 km, and the operation oil was water-glycol-based operation oil. . This test is a test performed by using a double-acting cylinder, assembling an evaluation sample in the rod packing part (or piston part), and operating the cylinder with pressure from a hydraulic source. Abrasion resistance was evaluated from the dimensional change of the packing and the appearance damage.

(4) Sealability A comprehensive evaluation of the operation test and the cylinder operation durability test was performed.

(A) Operation test An operation test was conducted at an environmental temperature of 100 ° C. The operating conditions are a load pressure of 21 MPa, an operating speed of about 200 mm / sec, a stroke of 50 mm, and the hydraulic oil is a water-glycol hydraulic oil. In this test, a sample for evaluation is assembled in the rod packing part of a penetration rod type test device (as shown in Fig. 1 with JIS B2409), and the rod is directly driven while applying pressure between both packings with a hydraulic source to perform an operation test. It is a test to be performed. The amount of external leakage (cc / 100m) during operation of 0 to 100 km was measured to evaluate the sealing performance.

(B) Cylinder operation endurance test The relief pressure was 21 MPa, the oil temperature was 60 ° C., the operation speed was about 100 mm / sec, the stroke was 250 mm, the operation distance was 1,000 km, and the operation oil was a water-glycol type operation oil. This test is a test performed by using a double-acting cylinder, assembling an evaluation sample in the rod packing part (or piston part), and operating the cylinder with pressure from a hydraulic source. The amount of external leakage (cc / 100m) during operation of 0 to 1,000 km was measured to evaluate the sealing performance.

(5) Seal life performance The material evaluation test and the operation test were comprehensively evaluated.

(A) Material evaluation test This is a deterioration test using a dumbbell with cloth (JIS B2403) in an environment of 120 to 160 ° C., and MAX 1,000 Hr was immersed in hydraulic oil. The characteristics of hardness, tensile strength, elongation, and volume were measured to evaluate the seal life.

(B) Operation test An operation test was conducted at an environmental temperature of 100 ° C. The operating conditions are a load pressure of 21 MPa, an operating speed of about 200 mm / sec, a stroke of 50 mm, and the hydraulic oil is a water-glycol hydraulic oil. In this test, a sample for evaluation is assembled in the rod packing part of a penetrating rod type test device (as shown in Fig. 1 with JIS B2409), and the rod is directly driven while applying pressure between both packings with a hydraulic source to perform an operation test. It is a test to be performed. The amount of external leakage (cc / 100m) during operation of 0 to 100 km was measured to evaluate the seal life.

(6) Measurement of elongation rate of base fabric A dumbbell test piece having a length of 100 mm and a thickness of 2 to 3 mm was prepared using a base fabric, a tensile test according to JIS / B2403 was performed, and the elongation rate at that time was measured.

  The present invention is an annular packing formed of a base fabric in which a base material is embedded in a rubber composition, and in particular, a cross section disposed between a piston and a cylinder has a substantially V shape or U shape. The annular packing of the present invention can be used in a wide variety of industrial fields such as power plant, chemical industry plant, tire industry, various equipment, and seals of sliding parts of devices.

4 packing, 41 annular packing, 4a outer base fabric, 4b inner base fabric, 10 molding die, 11 tape-shaped base fabric, 12 rubber composition, 13 warp, 14 weft.

Claims (7)

Forming a tape-like base fabric substrate is embedded in the rubber composition, an annular packing obtained by crosslinking the rubber composition see contains only hydrogenated nitrile rubber as a rubber component, the rubber The composition includes only a rubber component and a cross-linking agent .   The packing according to claim 1, wherein the hydrogenated nitrile rubber has an acrylonitrile content in a range of 25 mass% to 50 mass%.   The packing according to claim 1, wherein the elongation percentage of the base fabric after crosslinking is in the range of 35 to 60%.   The packing according to claim 1, wherein the base material is formed of a weave fabric made of warp and weft yarns of aramid fibers or a plain fabric of aramid fibers.   The packing according to claim 4, wherein the packing is formed of a laminate of a plurality of tape-like base fabrics, and the base material yarns constituting the base fabric intersect each other between the laminates.   The packing according to claim 1, wherein the cross section is V-shaped or U-shaped. A method for producing the packing according to claim 1 using an annular mold,
(A) impregnating a base material with a hydrogenated nitrile rubber composition solution and preparing a base fabric in which the base material is embedded in the rubber composition;
(B) a step of preparing a plurality of tape-shaped base fabrics obtained by cutting the base fabric into biases with a predetermined dimension;
(C) a step of sequentially arranging the tape-shaped base cloth on the surface of the annular mold along the entire circumference thereof;
(D) pressurizing the tape-shaped base fabric in the mold direction, and bringing the tape-shaped base fabric into close contact with each other to form a preform, and (e) pressurizing the preform. A method for producing a packing comprising a step of crosslinking by heating.

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