TWI727097B - Gasket containing talc tablets - Google Patents

Abstract

The present invention provides a gasket with improved sealing performance. The present invention provides a gasket comprising talc flakes containing talc, inorganic fibers and a binder, and the ten-point average roughness (R _Z ) of both sides of the talc flakes according to JIS B 0031 (1994) is 20 μm or less .

Description

Gasket containing talc tablets

The present invention relates to a gasket containing talc flakes used in pipe connections for fluids and the like.

Generally speaking, the three main types of gaskets are non-metal gaskets, semi-metal gaskets and metal sleeve gaskets. Among metal-free gaskets, under high temperature conditions above 450℃, sheet gaskets containing inorganic fillers and inorganic fibers with higher heat resistance are usually used, and woven gaskets obtained by pulling inorganic fibers through rubber .

In Japanese Patent Laid-Open No. 59-86683, a sealing material containing inorganic fibers, inorganic fillers and bonding agents is disclosed as a sealing material for metal-free gaskets.

However, when a gasket containing a sealing material containing inorganic fibers, inorganic fillers and bonding agents is used, it is clearly known that the fluid in the piping flows through the surface of the gasket and leaks to the outside. The so-called gasket and flange There is room for improvement of the sealing performance due to the leakage of the joints between them.

The object of the present invention is to provide a gasket with improved sealing performance.

The present invention provides the following gaskets containing talc flakes.

[1] A gasket comprising talc flakes containing talc, inorganic fibers and a binder, and the ten-point average roughness (R _Z ) of both sides of the talc flakes according to JIS B 0031 (1994) is 20 μm or less.

[2] The gasket according to [1], wherein the above-mentioned inorganic fiber is selected from the group consisting of alumina fiber, glass fiber, rock wool, basalt fiber, bio-soluble fiber, silica fiber and ceramic fiber At least 1 fiber in the group.

[3] The gasket according to [1], wherein the inorganic fiber is alumina fiber or basalt fiber.

[4] The gasket as described in [1], wherein the heat loss rate of the talc sheet at 800°C according to JIS K 7120 is 15% by weight or less.

[5] The gasket according to [1], wherein the particle size of the talc is 2 μm or more and 25 μm or less.

[6] The gasket according to any one of [1] to [5], which comprises a laminated body containing two or more of the above-mentioned talc sheets, and the laminated body comprises a metal plate, and the material of the metal plate is a stainless steel material Or carbon steel, the shape of the metal plate is at least one shape selected from the group consisting of flat metal, metal mesh, and hook metal.

[7] The gasket described in any one of [1] to [5], which is at least one gasket selected from the group consisting of spiral gaskets, semi-metal gaskets, and metal sleeve gaskets .

The above content and other objectives, features, aspects and advantages of the present invention can be clarified from the following detailed description related to the present invention understood in connection with the accompanying drawings.

Hereinafter, the gasket containing the talc sheet of the present invention will be further described in detail.

[Average aspect ratio of talc]

The average aspect ratio of the talc used in the present invention is preferably 10-25. The so-called average aspect ratio of talc is the ratio of the average diameter of the talc particles to the average thickness, which can be calculated from (average diameter/average thickness). When the average aspect ratio of the talc is less than 10, the R _{Z of} both sides of the talc sheet may exceed 20 μm. Furthermore, the upper limit of the average aspect ratio of talc is not particularly limited. Generally, the average aspect ratio of talc is 25 or less. The specific method for measuring the average aspect ratio of talc is based on the description in the following example.

[Average particle size of talc]

The average particle size of the talc used in the present invention is preferably 2 μm or more and 25 μm or less. When the average particle size of talc is less than 2μm, the formation of talc flakes tends to be difficult. When the average particle size of talc exceeds 25μm, the R _{Z of} both sides of the talc flakes may exceed 20μm. The average particle size of talc is measured using a laser diffraction particle size distribution measuring device, and the specific method for measuring the average particle size is based on the description in the following example.

[Inorganic Fiber]

The inorganic fibers used in the present invention play a role in improving the mechanical strength of the talc flakes. As such inorganic fibers, for example, alumina fibers, glass fibers, rock wool, basalt fibers, biosoluble fibers, silica fibers, and ceramic fibers are preferable. In order to improve heat resistance, it is more preferable to use alumina fiber, and in order to increase the mechanical strength, it is more preferable to use basalt fiber.

[Average fiber diameter of inorganic fiber]

The average fiber diameter of the inorganic fiber used in the present invention is preferably in the range of 3-20 μm. When the average fiber diameter of the inorganic fiber is greater than 20 μm, the R _{Z of} both sides of the talc flake may exceed 20 μm. When the average fiber diameter of the inorganic fiber is less than 3 μm, the mechanical strength of the talc flake tends to decrease. The specific measurement method of the average fiber diameter of the inorganic fiber is based on the description in the following example.

[Binder]

The binder used in the present invention may be any one that combines talc and inorganic fibers, improves sealing performance and can impart mechanical strength to the talc flakes. In order to better bond the talc and inorganic fibers in the talc flakes, Organic binders can be used. As the organic binder, for example, acrylonitrile butadiene rubber, natural rubber, isoprene rubber, chloroprene rubber, acrylic Nitrile rubber, styrene-butadiene rubber, butyl rubber, fluorine rubber, silicone rubber, ethylene-propylene rubber, etc. These adhesives can be used in combination of one type or two or more types.

[Ten point average roughness (R _Z )]

In the present invention, the ten-point average roughness (R _Z ) of both sides of the talc sheet according to JIS B 0031 (1994) is 20 μm or less. R _Z is to extract only the evaluation length (8mm) from the roughness profile in the direction of its average line, and find the average line from the extracted part in the direction of the longitudinal magnification from the highest peak to the fifth highest peak The sum of the average value of the absolute value of the elevation and the absolute value of the elevation from the lowest trough to the fifth lowest trough, expressed in micrometers (μm). The specific measurement method of R _Z is based on the description in the following example.

[Heat loss rate]

The talc sheet used in the present invention preferably has a heat loss rate of 15% or less at 800° C. in accordance with JIS K 7120 (thermogravimetric measurement method for plastics). If the heat loss rate of talc flakes at 800°C exceeds 15%, the sealing performance at high temperatures tends to decrease. The specific measurement method of the heat loss rate is based on the description of the following examples.

In addition to the above-mentioned components, the talc tablets used in the present invention may optionally contain various vulcanizing agents, vulcanization accelerators, vulcanization assistants, coloring agents, and the like.

[Gasket]

The gasket of the present invention includes the above-mentioned talc flakes. The gasket of the present invention can be easily manufactured, for example, by cutting the above-mentioned talc sheet into a desired shape. The gasket of the present invention may also contain two or more of the above-mentioned talc flakes. In addition, two or more talc flakes may be included, and auxiliary reinforcing materials such as thin metal plates, metal meshes, and hook metals may be included in order to increase the strength. As the material of the auxiliary strengthening material, stainless steel material (SUS material) or carbon steel material (SPCC material) can be used.

The gasket containing more than two talc tablets can be made by crimping more than two talc tablets. A layered body composed of two or more talc flakes in a sequential layered structure. In addition, the layered body including two or more talc flakes may have, for example, a structure in which talc flakes, auxiliary reinforcing materials, and talc flakes are sequentially laminated, and further include auxiliary reinforcing materials.

The above-mentioned talc sheet can also be used as the filler material of the spiral gasket or the surface material of the semi-metal gasket, and the core material of the metal sleeve gasket.

[Manufacturing Method of Talc Tablets]

The talc flakes contained in the gasket of the present invention can be manufactured using a dry method, a wet method, or the like, which is a normal non-woven fabric manufacturing method.

[Spiral Gasket]

The gasket of the present invention can be made into a spiral gasket by using the above-mentioned talc sheet as a filler material. Spiral gaskets can be manufactured, for example, by using stainless steel or carbon steel, nickel-chromium alloys, Hester alloys and other simple metals and alloys as the ring material, and the filler material and the ring material are superimposed and rolled into a spiral shape. .

[Semi-Metal Gasket]

The gasket of the present invention can be made into a semi-metal gasket by using the talc sheet as the surface material. Semi-metal gaskets can be manufactured, for example, by forming layers of talc sheets as surface materials on both sides of metals containing elemental metals and alloys such as stainless steel, carbon steel, nickel-chromium alloys, Hester alloys, etc., and made into a semi-metal shape. .

[Metal Sleeve Gasket]

The gasket of the present invention can be made into a metal sleeve gasket by using the above-mentioned talc sheet as the core material. The metal sleeve gasket can be manufactured, for example, by coating a thin film of a metal containing elemental metals and alloys such as stainless steel, carbon steel, nickel-chromium alloy, Hester alloy, etc., on the outer side of the talc sheet as the core material.

[Example]

Hereinafter, embodiments will be disclosed to further specifically explain the gasket of the present invention, but the present invention is not limited by these examples.

[Example 1]

A piece of talc (Nippon Talc (stock): MS-P (average particle size 15μm, average aspect ratio 15)) 80 parts by weight, alumina fiber (average fiber diameter 5-10μm) 10 parts by weight was prepared by the wet method, and A talc sheet of 10 parts by weight of acrylonitrile butadiene rubber, three test pieces were taken from the talc sheet, and the evaluation of _{R Z was performed.} In addition, three gaskets were produced from the talc sheet, and the sealing performance was evaluated. Furthermore, the talc flakes have a heat loss rate of 12.5% at 800°C in accordance with JIS K 7120.

[Example 2]

Except that the inorganic fiber was made into 7 parts by weight of alumina fiber (average fiber diameter 5-10 μm) and 3 parts by weight of basalt fiber (average fiber diameter 5-10 μm), it was produced under the same conditions as in Example 1, and evaluated. Furthermore, the heat loss rate of the talc flakes at 800° C. according to JIS K 7120 is 13.0%.

[Comparative Example 1]

A piece of vermiculite (Bellmitech (stock): No. 0 (average particle size 0.7mm)) 40 parts by weight, talc (Nippon Talc (stock): MS-P (average particle size 15μm), average vertical and horizontal Ratio 15)) 40 parts by weight, 10 parts by weight of rock wool (average fiber diameter 5-10μm), and 10 parts by weight of acrylonitrile butadiene rubber. Three test pieces are taken from the vermiculite/talc sheet , Carry out R _Z evaluation. In addition, three gaskets were produced from the vermiculite/talc sheet, and the sealing performance was evaluated. Furthermore, the heat loss rate of the vermiculite/talc flakes at 800° C. according to JIS K 7120 is 13.5%.

〔1〕Measurement conditions of average particle size of talc and vermiculite

The average particle size uses a laser diffraction particle size distribution measuring device (product name "SALD- 2000J" Shimadzu Corporation (Stock)), as the average particle size, in the particle size distribution measured by this device, the value of the particle size when the cumulative number becomes 50% (median particle size) is used.

〔2〕Measurement conditions of average aspect ratio of talc

The average aspect ratio is measured by observing at a magnification of 1000 using a scanning electron microscope (product name "S-3400N" manufactured by Hitachi High-Technologies Corporation). Specifically, the sample is fixed on the sample stage of the scanning electron microscope, and the scanning electron microscope is used to shoot, randomly select 20 particles in the captured images, measure the diameter and thickness of the talc particles, and then proceed Arithmetic average is used to calculate the average diameter and average thickness of the talc particles, and the ratio of the average diameter to the average thickness of the talc particles (average diameter/average thickness of the talc particles) is calculated and set as the average aspect ratio.

〔3〕Measurement condition of average fiber diameter of inorganic fiber

The average fiber diameter is measured by observation using a scanning electron microscope (product name "S-3400N" manufactured by Hitachi High-Technologies Co., Ltd.) at a magnification of 1000 times. Specifically, the sample is fixed on the sample stage of the scanning electron microscope, and the scanning electron microscope is used for shooting. 20 particles in the captured images are randomly selected to measure the fiber diameter, and then the arithmetic average is performed. This is set as the average fiber diameter.

〔4〕Measurement conditions of heat loss rate

Cut any part of talc flakes and vermiculite/talc flakes, prepare a test piece, measure the mass of the test piece, and set the mass before heating. The test piece was placed in an aluminum pan, and a TG/DTA simultaneous measurement device (manufactured by Shimadzu Corporation, trade name: DTG-60) was used as a thermal analysis device. The temperature rise rate was 10°C/min in an air environment ( The air flow rate is 150 ml/min). After heating from room temperature to 800°C, it is naturally cooled to room temperature. The mass was measured again, and set as the mass after heating. Using the obtained mass before heating and mass after heating, the heat loss rate is calculated using the following formula (1).

(1) Heat loss rate (%)=(mass before heating-mass after heating)/mass before heating×100

[5] Verification experiment conditions for the evaluation of _{R Z} on both sides of the sheet

_{The R Z on} both sides of the sheet was measured using Surfcom480A manufactured by Tokyo Precision Co., Ltd. in accordance with JIS B 0031 (1994). The measurement is performed on three test pieces taken from the same talc piece and three test pieces taken from the same vermiculite piece, and the R _Z measurement on both sides of the sheet is performed once.

Evaluation length: 8.0 mm, evaluation speed: 0.3 mm/s, critical value: 0.8 mm.

(R _Z evaluation standard)

_{A: R Z on} both sides of the sheet is 20 μm or less, B: R _{Z on} both sides of the sheet is a value greater than 20 μm.

The verification test results of the evaluation _{of R Z} on both sides of the sheet are shown in Table 1 below.

_{As shown in Table 1, the R Z of} both sides of the six test pieces taken from the talc flakes produced in Examples 1 and 2 are all less than 20 μm, but it is taken from the vermiculite/talc flakes produced in Comparative Example 1. _{The R Z of} both sides of the three test pieces all exceeded 20 μm.

(6) Verification test conditions for sealing evaluation

Install test gaskets 1 to 6 on the flange part of the compressed gas piping, and load the load so that the surface pressure becomes 10 MPa using a compression tester. Supply helium with a temperature of 35°C and a pressure of 0.2MPa to the compressed gas piping, and measure the helium leaking from the gasket with a soap film flowmeter.

(Evaluation criteria for leakage)

A: The leakage of helium is less than 5.0×10 ^-2 (Pa‧m ³ /s), B: The leakage of helium is ^{more than 5.0×10 -2} (Pa‧m ³ /s).

The results of the verification experiment are shown in Table 2 below.

As shown in Table 2, among the gaskets containing talc flakes produced in Examples 1 and 2, the leakage of helium in the six gaskets produced did not reach 5.0×10 ^-2 (Pa‧m ³ /s ), in contrast to this, in the gasket containing vermiculite and talc flakes produced in Comparative Example 1, the leakage of helium in the three gaskets produced is 5.0×10 ^-2 (Pa‧m ³ /s )the above. According to these results, the use _{of a gasket including talc sheets with R Z} of 20 μm or less on both sides can improve the leakage of the joint between the gasket and the flange.

The embodiment of the present invention has been described, but it should be considered that the embodiment disclosed this time is only illustrative in all aspects and not restrictive. The scope of the present invention is disclosed by the scope of the patent application, and is intended to include the meaning equivalent to the scope of the patent application and all changes within the scope.

Claims (6)

A gasket comprising talc flakes containing talc, inorganic fibers and a binder, and the ten-point average roughness (R _Z ) of both sides of the talc flakes according to JIS B 0031 (1994) is 20 μm or less, relative to the above 100 parts by weight of the talc flakes contain 80 parts by weight or more of the talc, the particle size of the talc is 2 μm or more and 25 μm or less, and the average aspect ratio of the talc is 10-25. The gasket of claim 1, wherein the inorganic fiber is at least one fiber selected from the group consisting of alumina fiber, glass fiber, rock wool, basalt fiber, biosoluble fiber, silica fiber and ceramic fiber . The gasket of claim 1, wherein the above-mentioned inorganic fiber is alumina fiber or basalt fiber. Such as the gasket of claim 1, wherein the heat loss rate of the above-mentioned talc sheet at 800°C in accordance with JIS K 7120 is 15% by weight or less. The gasket of any one of claims 1 to 4, which comprises a laminate containing two or more of the above-mentioned talc flakes, and the laminate comprises a metal plate, and the material of the metal plate is stainless steel or cold-rolled steel, the above The shape of the metal plate is selected from flat metal, metal mesh and hook metal At least one shape in the group. Such as the gasket of any one of claims 1 to 4, which is at least one gasket selected from the group consisting of spiral gaskets, semi-metal gaskets, and metal sleeve gaskets.