JP2901699B2 - Non-asbestos joint sheet - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a non-asbestos joint sheet used for a base material of a gasket used in a wide range of industrial fields such as a chemical industry, an automobile, a ship, and various kinds of equipment. The present invention relates to a non-asbestos joint sheet having excellent sealing properties.

TECHNICAL BACKGROUND OF THE INVENTION Conventionally, asbestos joint sheets have been used in large quantities as a base material for such gaskets.

In recent years, the use of such asbestos joint sheets has been in the direction of being restricted due to adverse effects on the human body, and for such reasons, non-asbestos joint sheets have begun to be used in place of asbestos joint sheets.

Such non-asbestos joint sheet, as a base fiber instead of asbestos, inorganic fibers other than asbestos such as glass fiber,
Alternatively, an organic fiber such as Kevlar pulp is used, and a thermosetting rubber is used as a binder in the same manner as the asbestos joint sheet.

However, the non-asbestos fiber used in the conventionally known non-asbestos joint sheet has poor wettability compared to the asbestos fiber, and a uniform composition in which the non-asbestos fiber is sufficiently dispersed in the rubber binder is obtained. Difficult, because of the non-asbestos joint sheet obtained for a long period of time, the resulting non-uniform material causes inconvenience (brittleness)
There is a problem that such occurs.

For this reason, in the conventional non-asbestos joint sheet, by reducing the amount of non-asbestos fibers in the composition constituting the joint sheet and using a large amount of a powdery filler, the composition can be made uniform. Attempts have been made to do so.

However, such a non-asbestos joint sheet has poor sealability at a joint portion as compared with an asbestos joint sheet, and is inferior in gas-gas tightness when attached to a joint such as a pipe through which a gas fluid flows particularly as a gasket. There is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems associated with the prior art as described above, wherein the material of the non-asbestos joint sheet is uniform, and a pipe or the like through which a gas fluid flows as a gasket. It is an object of the present invention to provide a non-asbestos joint sheet having excellent sealing properties even when attached to a joint.

SUMMARY OF THE INVENTION A non-asbestos joint sheet according to the present invention is a non-asbestos fiber comprising non-asbestos inorganic fiber and / or heat-resistant organic fiber.
In a plate-shaped non-asbestos joint sheet obtained by heating and compressing a joint sheet-forming composition containing a rubber binder and a filler, the composition comprises two or more kinds of plastics,
It is characterized in that it contains 0.001 to 0.9 denier ultra-fine plastic composite fiber (also referred to simply as "plastic fiber") in an amount of 1 to 15% by weight as a part of the heat-resistant organic fiber.

Further, in this non-asbestos joint sheet, it is preferable that the thickness of the plastic fiber is 0.05 to 0.1 denier, and the ratio of the plastic fiber in the composition is 3 to 10% by weight.

Specific description of the invention Hereinafter, the non-asbestos joint sheet according to the present invention will be specifically described.

The non-asbestos joint sheet according to the present invention is formed by kneading a composition for forming a joint containing non-asbestos fibers, a rubber binder and a filler, and then heating and compressing the composition.

In the non-asbestos joint sheet of the present invention, a base fiber composed of non-asbestos inorganic fibers and / or heat-resistant organic fibers conventionally used in a composition for forming a non-asbestos joint sheet is used.

Examples of such inorganic fibers include glass fiber, ceramic fiber, rock wool, mineral slag wool, fused quartz fiber, chemically treated silica fiber, fused silicate alumina fiber, alumina fiber, stabilized zirconia fiber, boron nitride fiber, and alkali titanate. Known inorganic fibers such as fibers, whiskers, boron fibers, carbon fibers, metal fibers, and sepiolite fibers are widely used as conventional base fibers for forming a non-asbestos joint sheet.

Further, as the organic fibers, aramid fibers, aromatic polyamide fibers, polyamide fibers, polyolefin fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl ether fibers, polyvinyl chloride fibers, polyurea fibers, Known organic fibers, such as polyurethane fibers, polyfluorocarbon fibers, phenol fibers, and cellulosic fibers, are widely used as conventional base fibers for forming a non-asbestos joint sheet.

Among these, aromatic polyamide fibers and fibrillated aromatic polyamide fibers, sepiolite fibers, glass fibers, and the like are preferable.

These non-asbestos fibers are used in an amount of 5 to 50 parts by weight based on 100 parts by weight of the composition for forming a joint sheet in combination with a plastic fiber described later.

Further, these non-asbestos fibers may be used alone or in combination of two or more.

Further, in the present invention, in addition to the inorganic fiber and / or the organic fiber, as a part of the non-asbestos fiber, the thickness of the fiber is 0.001 denier (assuming a polyester composite fiber having a circular cross section and a density of 1.1 g / cm ³ ). , Its fiber diameter is 0.0113μm) ~
0.9 denier (also 10.2 μm), preferably 0.05 denier (also 0.565 μm) to 0.1 denier (also 1.13 μm)
m) are used. Incidentally, ordinary fibers have a denier of several deniers, and even fine fibers have a denier of 1.0 denier or more.

Further, the fiber length of such an ultrafine plastic fiber is desirably about 0.5 to 8 mm.

Such ultra-fine plastic fibers are specifically two or more types of composite fibers formed from polyester, nylon, acrylic, polyurethane, polystyrene and the like. A sea-island composite fiber (a woven fabric manufactured by Toray Industries, Inc.) in which a plurality of polyester fibers that are spaced apart from each other are surrounded by nylon so that the cross section looks as if there are many polyester islands in the sea of nylon. Toraysee's original fiber),. Cross-section 1/4 at each of the four corners of the cross-shaped nylon fiber
(4) Cross-section radial conjugate fiber in which the corners of a circular polyester fiber are joined (such as "Berima X" manufactured by Kanebo Co., Ltd.); 2. Hollow cross-section radial conjugate fiber (such as the original fiber of Microstar, a woven fabric manufactured by Teijin Limited) in which polyester fibers are bonded to gaps between a plurality of hollow nylon fibers having a petal cross section. Polyester fibers and nylon fibers are commercially available as layered composite fibers having a cross section in which the fibers are alternately arranged in the longitudinal direction (such as raw fibers of woven cloth "Picem" manufactured by Toray Industries, Inc.).

The above composite fiber is prepared by aligning two types of high molecular components (for example, polyester and nylon) and then drawing one of the components and then melting one of the components, for example, the nylon component (sea-island method).
It can be manufactured by a method of exfoliating both components (split method) or stretching thinly using the force of high-speed fluid (split method).

Such a plastic fiber is used in an amount of 1 to 15 parts by weight, preferably 3 parts by weight, per 100 parts by weight of the composition for forming a joint sheet.
Used in amounts of up to 10 parts by weight.

Fillers include clay, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripoly stone,
Known fillers are widely used as conventional fillers for forming non-asbestos joint sheets, such as wollastonite and mica.

Such a filler is a composition for forming a joint sheet.
It is used in a proportion of 40 to 80 parts by weight per 100 parts by weight.

The rubber binder plays a role of binding the non-asbestos fibers, and a thermosetting rubber is generally used as the rubber binder.

Specific examples of such a thermosetting rubber include nitrile rubber (NBR), styrene butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), and ethylene-propylene rubber. (EPM),
Fluororubber (FPM), Silicone rubber (Si), Chlorosulfonated polyethylene (CSM), Ethylene vinegar (E
VA), polyethylene chloride (CPE), epichlorohydrin rubber (ECO), nitrile isoprene rubber (NIR), natural rubber (NR) and the like.

In the present invention, a thermoplastic resin and / or a thermoplastic elastomer may be used together with the thermosetting rubber as the rubber binder.

Examples of the thermoplastic resin in this case include polyamide, polyethylene, polypropylene, ethylene-propylene copolymer, polyester, and tetrafluoroethylene resin.

As the thermoplastic elastomer, styrene,
For example, styrene-butadiene copolymer, olefin,
For example, a polymer blend of polypropylene and ethylene-propylene, a block copolymer of a urethane-based polymer chain composed of a diisocyanate and a short-chain glycol such as ethylene glycol, and a diisocyanate and a long-chain polyol such as a polyalkylene glycol. Copolymers, such as ester-based, for example, a block copolymer of polyester and polyether such as a condensate of 1,4-butanediol and terephthalic acid, and others, butyl rubber-grafted polyethylene,
Non-crosslinked thermoplastic elastomers such as trans 1,4-polyisoprene, and crosslinked thermoplastic elastomers such as ionomers.

Such a rubber binder is generally used in a proportion of 5 to 25 parts by weight based on 100 parts by weight of the composition for forming a joint sheet.

When a thermoplastic resin and / or a thermoplastic elastomer is used for the rubber binder, the compounding ratio thereof is as follows:
0.1 to 40 parts by weight per 100 parts by weight of thermosetting rubber or 0.005 to 10% by weight based on the entire joint sheet
Similarly, the content is preferably 0.5 to 15 parts by weight per 100 parts by weight of the thermosetting rubber in terms of solid content, or 0.025 to 3.75% by weight based on the whole joint sheet.

The thermosetting rubber used as the rubber binder, for example, SBR may be an oil-extended rubber in which a naphthenic process oil is blended. Furthermore, such an oil-extended rubber and the above-described thermosetting rubber can be used in combination.

The composition for forming a non-asbestos joint sheet used for forming the non-asbestos joint sheet according to the present invention includes, for example, 1) a vulcanizing agent such as sulfur, zinc oxide, peroxide, dinitrosobenzene, and 2) a thiazole compound. And rubber chemicals such as vulcanization accelerators such as polyamine compounds, sulfenamide compounds, dithiocarbamate compounds, aldehydeamine compounds, guanidine compounds, thiourea compounds and xanthate compounds.

The amount of such a rubber chemical in the composition for forming a joint sheet is appropriately determined according to the amount of the thermosetting rubber and the thermoplastic elastomer in the composition. Usually, the total amount of the rubber chemical and the rubber binder is 5 to 25 parts by weight based on 100 parts by weight of the composition for forming a joint.

The non-asbestos joint sheet according to the present invention is manufactured, for example, as follows.

That is, a rubber binder is dissolved in a rubber material solvent such as toluene or rubber volatiles, and a rubber chemical containing a vulcanizing agent is mixed therein. The obtained dispersion is mixed with the plastic fiber according to the present invention, an inorganic fiber and / or an organic fiber other than asbestos, and a filler and kneaded so as to be uniform to form a clay-like non-asbestos joint sheet. Composition. Next, this composition is inserted between a pair of rolls composed of a hot roll and a cooling roll, and heated and rolled. At this time, the heating roll is at a temperature of 120 to 160 ° C, and the cooling roll is
Preferably, the temperature is maintained at 50 ° C. or lower, and an apparatus having such a pair of rolls is known as a sheeter apparatus. When the composition for forming a non-asbestos joint sheet is inserted between a pair of rolls in this manner, the composition is heated and rolled and laminated in a sheet shape on the hot roll side. When this sheet-shaped composition is peeled off from the hot roll, the non-asbestos joint sheet according to the present invention is obtained.

The rubber solvent evaporates almost completely in the kneading step and the heating and rolling step of the composition for forming a non-asbestos joint sheet.

Also, when the non-asbestos joint sheet forming composition is inserted between a pair of rolls and rolled into a sheet, a part of the composition may adhere to the cooling roll. The adhesion of the non-asbestos joint sheet forming composition of the present invention can be performed, for example, by adding an organic antistatic agent to the composition in an amount of 0.1
It can be prevented by adding で 10% by weight. Examples of organic antistatic agents include cationic antistatic agents such as lauryl trimethyl ammonium chloride, anionic antistatic agents such as alkyl sulfates, nonionic antistatic agents such as polyoxyethylene alkyl ether, and amphoteric charging agents such as betaine. An antioxidant or a silicon compound-based antistatic agent is used.

Effect of the Invention According to the present invention, a joint sheet is formed using a composition for forming a joint sheet containing 1 to 15% by weight of a plastic fiber having a fiber thickness of 0.001 to 0.9 denier as a part of non-asbestos fiber. Since it is formed, a non-asbestos joint sheet with less voids and a dense material can be obtained with good moldability, and when the obtained non-asbestos joint sheet is attached to a joint such as a pipe through which a gas fluid flows as a gasket, There is a feature that the sealing property against gas fluid, especially the sealing property against permeation leakage is excellent.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 3 A nitrile rubber was dissolved in toruene, and sulfur and zinc white were mixed as vulcanizing agents.

In the resulting dispersion, fibril aramid fiber, non-asbestos fiber I consisting of glass fiber and sepiolite, filler consisting of wollastonite and talc, and nylon fiber component as plastic fiber cross-sectional sea-like component and polyester component island-like cross-section Sea-island composite fibers with a thickness of 0.05 denier (commercial name: Toraysee (manufactured by Toray); fiber length
4mm) and kneaded to obtain a composition for forming a non-asbestos joint sheet. The composition is shown in Table 1.

Next, the composition for forming a non-asbestos joint sheet was supplied to a sheeter device provided with a hot roll and a cooling roll, and was heated and compressed at 140 ° C. to form a non-asbestos joint sheet having a thickness of 0.8 mm.

With respect to the obtained non-asbestos joint sheet, measurement, evaluation and LCC 50% test of density, flexibility and sealability were performed as follows.

 The results are shown in Table 1.

 Density and: Measured and evaluated based on JIS R 3453.

Flexibility sealability: between two flanges are joined portion of the pipe, fitted with a non-asbestos joint sheet as a gasket, N ₂ gas in the piping and pressure gasketed tightening as 200kg / cm ² (10kg /
cm ² ) and the gasket leaks from the gasket part for two types, one with and without a sealant applied to the gasket.
The amount of N ₂ gas was measured.

LCC50%: Increase in thickness of non-asbestos joint sheet when gasket is immersed in a 50/50 wt% mixed solution of water / ethylene glycol at 100 ° C for 22 hours in this solution (Δt%)
And the weight increase (Δw%) was measured.

Comparative Example In Examples 1 to 3, the composition of the composition for forming a non-asbestos joint sheet was changed to the first composition without adding the plastic fiber according to the present invention to the composition for forming a non-asbestos joint sheet.
Except for the values in the table, a non-asbestos joint sheet was formed in the same manner as in Examples 1 to 3, and the obtained non-asbestos joint sheet was subjected to measurement and evaluation of density, flexibility, sealability and an LCC 50% test. .

 The composition and the results are shown in Table 1.

From Table 1, it can be seen that by using the plastic fiber according to the present invention, the non-asbestos joint sheet has high density and improved flexibility, and the gas fluid flows through such a non-asbestos joint sheet according to the present invention. When used for a gasket in a joint part of a pipe, regardless of the presence or absence of a seal paste in this part, the seal against gas fluid is compared with a conventional non-asbestos joint sheet not using the plastic fiber according to the present invention. Is excellent.

Claims (2)

(57) [Claims] 1. A plate-like non-asbestos joint sheet obtained by heating and compressing a joint sheet-forming composition containing non-asbestos fibers composed of non-asbestos inorganic fibers and / or heat-resistant organic fibers, a rubber binder and a filler. A composition comprising at least two plastics;
A non-asbestos joint sheet comprising 001 to 0.9 denier ultra-fine plastic composite fiber in an amount of 1 to 15% by weight as a part of heat-resistant organic fiber. 2. The thickness of the ultrafine plastic composite fiber is
2. The non-asbestos joint sheet according to claim 1, which has a denier of 0.05 to 0.1 and a ratio of the plastic fiber in the composition of 3 to 10% by weight. 3.