JP2002105868A - Method for producing sealing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a sealing sheet-whose strength anisotropy is controlled and whose gas-sealing property and the like are excellent. SOLUTION: This method for producing the sheet-like seal material, characterized by mixing a rubber material as an organic binder with rubber chemicals and a solvent or dispersant for the rubber material, or mixing a resin as an organic binder with a solvent or dispersant for the resin, impregnating a nonwoven fabric comprising substrate fibers with the obtained binder mixture liquid and simultaneously removing a gas contained in the nonwoven fabric, evaporating and removing at least a part of the solvent or dispersant from the nonwoven fabric impregnated with the mixture liquid, and then heating and compressing the nonwoven fabric to vulcanize the rubber material or cure the resin to obtain the sheet-like seal material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sheet-like sealing material, and more particularly, to a method for suppressing strength anisotropy,
The present invention also relates to a method for producing a sheet-like sealing material having excellent gas sealing properties.

[0002]

BACKGROUND OF THE INVENTION At present, various types of gaskets are used for general industry, but the most versatile one is a joint sheet mainly composed of fibers and fillers and rubber or resin. Alternatively, a beater sheet is used. Here, the joint sheet is made of inorganic fibers such as asbestos and glass fibers, or organic fibers such as aromatic polyamide fibers and fibrillated aromatic polyamide fibers as base fibers, to which rubber, resin and binder as binders are added. A rubber sheet such as a sulfurizing agent and a filler are added and kneaded to prepare a composition for forming a joint sheet, and this composition is heated and rolled by being inserted between a pair of rolls including a hot roll and a cooling roll, It is obtained by laminating the composition for forming a joint sheet on the hot roll side and then peeling off the sheet material laminated on the hot roll.

[0003] A beater sheet is obtained by adding a filler and a rubber or resin to asbestos fibers or non-asbestos fibers in a beater, stirring them, uniformly dispersing them in water, and then forming them with a paper machine. . These sheets are relatively inexpensive, easy to produce large size products, easy to process into various shapes, easy to handle, and can seal fluid even with relatively low tightening force. It has various features, such as possible. However, these joint sheets and beater sheets also have problems.

[0004] As a first problem of the joint sheet,
There are restrictions on the fibers that can be used in the production process. In manufacturing a joint sheet, the wettability between the raw material, fiber, and rubber or resin is important, and if the wettability is poor, the sheet will be wrinkled or broken during sheet formation. At present, there are asbestos joint sheets containing asbestos fibers with good wettability with rubber or resin, and non-asbestos joint sheets containing no asbestos fibers (non-asbestos joint sheets), but have poor wettability with rubber. There are very few joint sheets using carbon fibers or the like alone as a fiber type, and most of non-asbestos joint sheets on the market contain a small amount of p-aramid fiber. Limitations on the types of fibers that can be used are a major constraint in improving the quality of gasket materials.

As a second problem, there is a restriction on the use of asbestos fibers. Asbestos joint sheet is an excellent product that can maintain excellent properties for a long time under high temperature, can be used for various fluids at various temperatures and has high versatility. The use of asbestos joint sheets is being replaced by other gaskets.

[0006] The third problem is that the non-asbestos joint sheet, when used in a real machine at a high temperature for a long time, has, for example, sealability, tensile strength, elongation at break, etc., as compared with the asbestos joint sheet. Is inferior in the property of maintaining excellent performance (also referred to as “long-term soundness”). This means that the non-asbestos sheet is liable to be hardened due to the history of high-temperature air, and as a result, is liable to be broken when used for a long time at a high temperature in an actual machine.

In the case of an asbestos joint sheet, by setting the compounding ratio of the asbestos fiber which is responsible for the strength to be high, it is possible to reduce the influence of the curing of the compounded rubber or resin itself on the curing of the entire sheet. On the other hand, in the case of a non-asbestos joint sheet, p-aramid fiber is generally blended as a strength improver, but the fiber has poor wettability and the strength of the sheet increases even if a large amount of p-aramid fiber is blended. Instead, other properties and processability often deteriorate, and it is difficult to mix the fibers in large amounts, and as a result, the curing of the rubber or resin itself leads to the curing of the entire sheet.

As a fourth problem, in the case of a joint sheet, the strength anisotropy of the sheet cannot be excluded due to the manufacturing method (see Table 1). This is because the fibers to be blended are oriented almost uniformly by the compression vulcanization process using a calender roll. In the case of asbestos joint sheet,
By setting the mixing ratio of the asbestos fibers high, the strength of the entire sheet is remarkably increased, whereby the above-described strength anisotropy can be complemented.

On the other hand, in the case of a non-asbestos joint sheet, the fiber blending ratio cannot be set high, and the fibers to be blended cannot complement the above-described strength anisotropy. Therefore, when stress is generated inside the gasket due to the hardening of the rubber during actual use at high temperatures for a long period of time, it is presumed that the stress concentrates in the direction of weak strength or in that part, and as a result, cracking of the gasket is induced. You.

On the other hand, the beater sheet has a problem in airtightness. Generally, the beater sheet is used for sealing a liquid such as lubricating oil or fuel oil, and specifically used for an oil pan or a fuel pump. On the other hand, it is not used as a gasket, such as a gaseous fluid, which requires strict airtight performance. Regarding gaskets obtained by the beater sheet manufacturing method currently on the market,
F37-B ", gasket surface pressure 19.6MP
a, the internal pressure of nitrogen was set to 0.98 MPa, and the amount of fluid leakage from the outer diameter of the gasket was measured to be 6.3 × 10 ^−2.
Pa · m ³ / s was shown (see Table 1). It is considered that such a large amount of gas leakage is due to the fact that some of the voids included in the sheet in the papermaking process remain without being removed during the manufacturing process. Under actual use conditions, generally, the presence or absence of leakage of gaseous fluid from the gasket is determined by the soapy water foaming method. In this soapy water foaming method, a test is performed on the flange of the actual machine (piping for gaseous fluid). Attach gasket for
After applying the soapy water to the outer diameter side of the gasket or the gap between the flanges, it is determined whether or not the gaseous fluid is leaking from the connection portion of the gaseous fluid pipe based on the presence or absence of bubbles. The detection sensitivity in this soap water foaming method is about 2 × 10 ^-4 P
is a · m ³ / s. Since the beater sheet generally shows a leak amount of 18 to 550 times the detection sensitivity of the soap water foaming method, the beater sheet has low sealing performance and is unsuitable as a sealing material for gaseous fluid. The sealing material for gas needs to have a sealing performance showing a leakage amount of 2 × 10 ⁻⁴ Pa · m ³ / s or less.

However, a sealing material obtained by the above-mentioned beater sheet manufacturing method and having excellent gas sealing performance and the like has not been known so far. Therefore, the present inventors have conducted intensive studies to solve the above problems, and as a result, a rubber material as an organic binder, a rubber chemical, and a solvent or a dispersion medium for the rubber material are mixed, or the organic material is mixed. A resin as a system binder is mixed with the solvent for a resin or the dispersion medium, and the resulting binder mixture is expelled (forcibly) into a non-woven fabric made of a base fiber by removing a gas present inside the non-woven fabric. And at least a part of the solvent or the dispersion medium is volatilized and removed from the non-woven fabric impregnated with the mixed solution, and then the non-woven fabric is heated and compressed to cure the rubber material or to cure the resin. In order to complete the present invention, it was found that when a sheet-like sealing material was produced, it was found that strength anisotropy was suppressed, and that a sheet-like sealing material having remarkably excellent gas sealing properties was obtained. Was Tsu.

Japanese Patent Application Laid-Open No. Sho 57-116970 discloses that a base material is formed by laminating one or two or more nonwoven fabrics made of hydrophobic short fibers such as tetron and nylon, on which resin and rubber are bonded. There is disclosed a packing for food machine equipment molded by impregnating with a binder such as described above. Also,
This publication describes that the above-mentioned base material is impregnated with a binder such as a resin or rubber and dried, and then subjected to pressure molding to produce the packing for food machine equipment. The publication also states that this packing has excellent sealing properties and is sanitary. However, since the impregnation step included in the publication is resin impregnation for the purpose of preventing fiber scattering and corrosion of the packing, the packing obtained by the method described in the publication discloses a packing material that strictly restricts leakage. In order to use it, it is not enough in terms of sealing properties of gas, liquid and the like.

In addition, Japanese Patent Publication No. 8-3086 discloses that, by dispersing colloidal particles of a silicone resin or colloidal particles of a polytetrafluoroethylene resin and an acrylic primer in water, the ignitability and harmfulness due to volatilization are dispersed. A water-dispersed emulsion having no emulsion was prepared, and the whole inside of a needle mat formed by needle punching a flocculent material mainly composed of glass fiber was impregnated with the emulsion. By evaporating water, a silicone resin or a polytetrafluoroethylene resin and an acrylic primer are attached to the entire inside of the needle mat, and a release paper with an acrylic adhesive is attached to the surface of the needle mat. A method for manufacturing a packing material for a combustion appliance is disclosed. Also, in this publication, an emulsion of an aqueous dispersion is stored in an immersion tank, and the needle mat is continuously fed by a roller feeder to the emulsion while adding 20 to 10 to the emulsion.
It is described that the emulsion is impregnated into the entire interior of the needle mat by immersion for about 0 seconds. In addition, by using the water-dispersed emulsion, it is possible for the first time to impregnate the entire interior of the needle mat with the emulsion, and the surface of all the glass fibers constituting the needle mat and the silicone resin or the space between the fibers are used. It states that a PTFE resin can be attached.

However, the method described in the above publication does not include a compression molding step, and the hermeticity of the packing is not improved. Or, it is insufficient in terms of liquid sealing properties.

[0015]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, and there is no limitation on the type of fiber to be blended, and it can be used for a long time under a high temperature condition. An object of the present invention is to provide a method for manufacturing a sheet-like sealing material that can be used as a substitute for a sheet and can be suitably used for sealing gas or liquid.

[0016]

SUMMARY OF THE INVENTION A first method for producing a sheet-like sealing material according to the present invention is obtained by mixing a rubber material as an organic binder, a rubber chemical, and the rubber material solvent or dispersion medium. The binder mixed solution is impregnated into the nonwoven fabric made of the base fiber, while expelling the gas present inside the nonwoven fabric, and volatilizing and removing at least a part of the solvent or the dispersion medium from the nonwoven fabric impregnated with the mixed solution, The nonwoven fabric is heated and compressed, and the rubber material is vulcanized to obtain a sheet-shaped sealing material.

In the first manufacturing method according to the present invention,
Preferably, the binder mixture is used in the form of a latex. A second method for producing a sheet-like sealing material according to the present invention comprises mixing a resin as an organic binder with the solvent or dispersion medium for a resin, and forming the obtained binder mixture into a nonwoven fabric made of a base fiber. In addition, the gas present inside the non-woven fabric is expelled and impregnated, at least a part of the solvent or the dispersion medium is volatilized and removed from the non-woven fabric impregnated with the mixed solution, and then the non-woven fabric is heated and compressed to remove the resin. It is characterized in that it is cured to obtain a sheet-shaped sealing material.

In any of the above methods for producing a sheet-like sealing material according to the present invention, it is preferable that the base fiber is a non-asbestos fiber. In any of the methods according to the present invention, the nonwoven fabric is preferably in a felt shape. In any of the methods according to the present invention, the binder mixture preferably contains a filler.

In any of the above methods according to the present invention,
The step of expelling gas present inside the nonwoven fabric and impregnating the binder mixed solution is performed by immersing the nonwoven fabric in the binder mixed solution while compressing the nonwoven fabric in advance, or compressing the nonwoven fabric in the binder mixed solution, and then immersing the nonwoven fabric in the binder mixed solution. It is preferable to carry out the restoration by spontaneous restoration.

In any of the above methods according to the present invention,
Preferably, the step of driving out the gas present inside the nonwoven fabric and impregnating with the binder mixed solution is performed by spraying the binder mixed solution onto the nonwoven fabric under high pressure. In any of the above methods according to the present invention, the step of driving out the gas present inside the nonwoven fabric and impregnating the binder mixture is performed by putting the nonwoven fabric in a reduced-pressure container, reducing the pressure inside the container, and then injecting the binder mixture. It is preferable to carry out the following.

According to the method for producing a sheet-like sealing material according to the present invention, there is no strength anisotropy, there is no limitation on the type of fiber to be blended, and it can be suitably used for a long time for sealing gas or liquid under high temperature conditions Thus, a sheet-like sealing material that can be used is obtained.

[0022]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method for producing a sheet-like sealing material according to the present invention will be specifically described. In the first method for producing a sheet-like sealing material according to the present invention, a rubber material as an organic binder, a rubber chemical, and a solvent or dispersion medium for the rubber material are mixed, and the obtained binder mixed solution is The non-woven fabric made of the base fiber is impregnated with the gas present inside the non-woven fabric, and at least a part of the solvent or the dispersion medium is volatilized and removed from the non-woven fabric impregnated with the mixed solution. Then, the rubber material is vulcanized to produce a sheet-like sealing material.

In the second method for producing a sheet-like sealing material according to the present invention, the binder mixed solution in the first production method may be a resin as an organic binder and a solvent or a dispersion medium for the resin. Are basically the same as in the first production method, except that the obtained binder mixture is used. That is, in the method of manufacturing a sheet-shaped sealing material of the present invention, unlike the conventional method of manufacturing a joint sheet, a calender roll manufacturing method, when a nonwoven fabric is used as a base fiber, and when a nonwoven fabric is impregnated with a binder mixed solution. The feature is that the gas in the non-woven fabric is forcibly expelled so that the gas does not exist in the non-woven fabric filled with the binder mixed solution. Thus, the binder mixed solution (compound) is converted into the non-woven fabric. After impregnating and forcibly expelling the gas, the solvent component or dispersion medium in the binder mixture liquid impregnated into the non-woven fabric as described above is volatilized and removed. A sheet-shaped sealing material having excellent long-term sealing properties and no strength anisotropy can be manufactured.

Hereinafter, the binder mixed solution, the nonwoven fabric, the impregnation method, and the like will be sequentially described in detail. <Binder mixed solution> In the binder mixed solution, the organic binder contained as described above may be a rubber material or a resin, and may further contain both of them. This contributes to improving the sealing performance of the sheet-shaped sealing material.

When the organic binder is a rubber material, the binder mixture contains, in addition to the rubber material, a rubber chemical, a solvent or a dispersion medium for the rubber material, and, if necessary, a filler or the like. You may. When the organic binder is a resin, the binder mixture contains a solvent or a dispersion medium for the resin in addition to the resin, and may further contain a filler if necessary.

Examples of the rubber material include natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, urethane rubber, chloroprene rubber, acrylonitrile butadiene rubber, butyl rubber, ethylene propylene rubber, acrylic rubber, silicone rubber, fluorine rubber and the like. Can be Examples of the resin include urea-based, melamine-based, polyester-based, epoxy-based, and phenol-based resins. In the present invention, the kind of these binders is not particularly limited, and one kind or a combination of two or more kinds may be used.

As the rubber chemicals, conventionally known rubber chemicals can be widely used, for example, vulcanizing agents, vulcanizing aids, accelerators, antioxidants, etc., and if necessary, thickeners, heat-sensitive gelling agents. (Thermosensitive agent), a surfactant and the like may be used. Examples of the thickener include synthetic polymers such as polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, and polyacrylamide, and alginates thereof; natural and semi-synthetic polymers such as casein, gelatin, and quagum; Is mentioned.

Examples of the heat-sensitive gelling agent (heat-sensitive agent) include, in addition to polyvinyl methyl ether, silicone-based and polyalkylene oxide derivative-based ones. As the surfactant, anionic, nonionic, cationic,
Known ones such as amphoteric can be widely used, for example,
Anionic surfactants such as carboxylate type, sulfonate type, sulfate type and phosphate type; nonionic type surfactants such as polyoxyethylene derivative type and polyhydric alcohol type derivative; alkylamine salt type; Cationic surfactants such as quaternary ammonium salts; and the like.

Such a thermosensitive gelling agent (thermosensitive agent) is usually used in an amount of 1 to 10 parts by weight, based on 100 parts by weight of the binder.
Preferably, it is contained in an amount of 2 to 5 parts by weight. Further, such a surfactant may be contained in an amount of usually 0.2 to 5 parts by weight, preferably 0.4 to 4 parts by weight, based on 100 parts by weight of the solid content in the binder mixture. desirable.

The filler is used as needed and contributes to the stress relaxation property and the improvement of the sealing performance of the sheet-like sealing material. As such a filler, specifically, for example, talc, mica, clay, oxidized material, etc. Examples include inorganic powders such as magnesium and calcium carbonate. In the present invention, these fillers are used alone or in combination of two or more.

In the present invention, when the total weight of the solid content in the binder mixture and the nonwoven fabric is 100% by weight, the rubber material and / or the resin is usually
It is used in an amount of 5 to 40% by weight, preferably 10 to 30% by weight. When the content of the rubber material and / or the resin serving as the binder is less than 5% by weight, the surface of the fibers constituting the nonwoven fabric and the surface of the filler used as required cannot be sufficiently covered, or the binder in the voids inside the nonwoven fabric cannot be sufficiently covered. The mixed liquid (compound) cannot be filled, and as a result, the sealing performance of the sheet-shaped sealing material may be reduced (see Table 1). On the other hand, when the content of the rubber material and / or the resin exceeds 40% by weight, an excessive amount of a component which is likely to be hardened or shrunk due to heat history contained in the obtained sheet-like sealing material becomes excessive. Hardening and cracking due to history are likely to occur, and it may be difficult to maintain properties such as excellent gas sealing properties and liquid sealing properties for a long period of time.

When a filler is used, it is usually 8% in a total of 100% by weight of the solid content in the binder mixture and the nonwoven fabric.
It is used in an amount of 0% by weight or less, preferably 5 to 80% by weight. When the content of the filler exceeds 80% by weight, the amount of the binder for sufficiently covering the surface of the filler is insufficient, and the sealing performance of the sheet-shaped sealing material may be reduced. If the content of the filler is less than 5% by weight, the effect of adding the filler, such as the stress relaxation property of the sheet-like sealing material and the improvement of the sealing performance, cannot be expected much.

The binder mixed solution containing such various components is used in a fluid state, and may be in a latex state, a solution state, etc. Specifically, for example, a solution rubber (a mixture of a solid rubber and a solvent) It is used as a liquid rubber (for example, liquid rubber without solvent such as liquid silicone rubber and liquid fluorine rubber), rubber latex, solution resin, resin emulsion and the like. These binder mixtures may be used alone or in combination of two or more.

The method for preparing such a binder mixture is as follows.
There is no particular limitation, and a conventionally known method may be adopted. <Non-woven fabric> A non-woven fabric is a base material of a sheet-shaped sealing material and contributes to the improvement of its strength.
Both asbestos-based and non-asbestos-based materials can be used, and non-asbestos-based nonwoven fabrics are preferably used from the viewpoint of safety to the human body and environment. Among such non-asbestos-based nonwoven fabrics, for example, p-aramid fiber Fibers having high strength at a high temperature, such as fluororesin fibers, carbon fibers, ceramic fibers, and mineral fibers, can be suitably used alone or in combination.

There are various methods for producing such a nonwoven fabric, such as a wet process, a dry process, a spunlace, a spunbond, a melt blown, a needle punch, and a stitch bond, and the type of the nonwoven fabric used in the present invention is different from the present process. There is no restriction. The properties of the obtained nonwoven fabric are preferably needle punch felt shape, wet papermaking nonwoven shape, and the like.

In the present invention, the above-mentioned nonwoven fabric which contributes to the improvement of the strength of the sheet-shaped sealing material is usually 5 to 5% by weight in total of 100% by weight of the solid content in the binder mixture and the nonwoven fabric (or nonwoven fabric fibers). 80% by weight, preferably 10-7
It is used in an amount of 0% by weight. When the content of the nonwoven fabric (or fiber) is less than 5% by weight, a sheet strength that can withstand actual use cannot be obtained. On the other hand, when the content exceeds 80% by weight, voids in the nonwoven fabric increase as the content of the nonwoven fabric increases. As a result, the amount of the binder mixed liquid to be impregnated and filled in the voids becomes insufficient, and a sheet-like sealing material having sufficient sealing performance tends to be unable to be obtained.

<Step of Preparing Binder Mixture (Step 1)
In the present invention, in the case where rubber is used as the binder, a solvent or a dispersion medium for the binder, a filler used as necessary, and a binder, a rubber chemical (eg,
Vulcanizing agents, vulcanizing aids, accelerators, anti-aging agents, etc.) are placed in a stirring vessel, and stirred and mixed until uniform to prepare a binder mixture (compound). At this time, if necessary
A thickener, a heat-sensitive gelling agent (heat-sensitive agent), a surfactant and the like may be added. Such stirring / mixing is usually performed at normal temperature (20 to 30 ° C.) and normal pressure, and if necessary, the mixture may be heated to a temperature at which the components do not undergo a chemical change or the like.

<Impregnation of Binder Mixture and Purging of Gas
Step (Step 2)> Next, in the present invention, the gas present inside the nonwoven fabric is forcibly driven out, and the binder mixed solution obtained as described above is impregnated into the nonwoven fabric made of the base fiber. Here, in order for the sheet-like sealing material to have excellent sealing performance, it is necessary to completely replace the voids present inside the nonwoven fabric with the binder mixed solution.

In order to completely fill the voids with the binder mixture in the present invention, the process of forcing gas (usually air) present inside the nonwoven fabric and impregnating with the binder mixture is described below. It is desirable to carry out by the method described in any of the above. That is: a method in which the nonwoven fabric is compressed and immersed in a binder mixed solution in advance and spontaneously restored in the binder mixed solution (also referred to as a “pre-compressed liquid spontaneous restoration method”); A method in which a nonwoven fabric is compressed in a mixture and then spontaneously restored in a binder mixture (also referred to as a “compression in liquid spontaneous restoration method”); (Also referred to as “high-pressure spraying”); or: A method in which a nonwoven fabric is placed in a reduced-pressure container, the inside of the container is reduced in pressure, and then a binder mixed solution is injected (“low-pressure injection method, reduced-pressure replacement method”). Is also preferred.);

This method (pre-compressed liquid spontaneous restoration method)
Then, the gas is extruded by pre-pressing and compressing the non-woven fabric to reduce the voids in which the gas is present, and the non-woven fabric having the reduced / removed voids is immersed in the binder mixture, and the non-woven fabric is mixed in the binder mixture. When the pressure is released, the nonwoven fabric spontaneously restores to its original shape. At this time, the inside of the nonwoven fabric is in a negative pressure state, and the binder mixed solution is sucked and penetrates into the nonwoven fabric, so that the fiber gap constituting the nonwoven fabric can be completely filled with the binder mixed solution.

In the above method (compression in liquid spontaneous restoration method), except that the nonwoven fabric is immersed in a binder mixed solution, the nonwoven fabric is pressed and compressed, and the nonwoven fabric is spontaneously restored by releasing the pressure. It is similar to the above method. Also,
In the method (high-pressure spraying method), the binder mixed solution sprayed at high pressure on the surface of the nonwoven fabric may be depressurized and sucked by a suction device provided on the back surface of the nonwoven fabric, so that the spraying and impregnation of the binder mixed solution may be made more efficient. .

In the method (injection under reduced pressure), the voids inside the nonwoven fabric are replaced with a binder mixed solution under reduced pressure. When the container is kept under reduced pressure, the voids in the nonwoven fabric are also reduced under reduced pressure. Becomes When the binder mixture is poured into the container under such reduced pressure, the binder mixture diffuses into the container under negative pressure and also penetrates into the voids in the non-woven fabric. It can be filled with a binder mixture. Such a vacuum injection method is effective, for example, when a nonwoven fabric is relatively small in size, without requiring large-scale equipment.

In the present invention, the method of restoring the compressed nonwoven fabric is preferably spontaneous restoration by release of pressure as described above, but may be forcibly restored. In addition, if the method (operation) above is performed only once, the amount of the binder mixed solution impregnated into the nonwoven fabric is insufficient due to the difficulty in adapting the nonwoven fabric to the binder mixed solution or the viscosity of the binder mixed solution. It is desirable to repeat the method a plurality of times to completely fill the fiber gaps constituting the nonwoven fabric with the binder mixture.

Even if the nonwoven fabric is impregnated with the binder mixed solution, if the nonwoven fabric has water repellency and repels the binder mixed solution, the binder mixed solution must be prepared in advance in the above-mentioned "binder mixed solution preparation step". It is desirable to add a surfactant to the liquid. In addition, the viscosity of the binder mixed solution is low, and a part of the binder mixed solution impregnated in the nonwoven fabric may flow out, and voids may be generated inside the nonwoven fabric again. In such a case, it is desirable to add a thickener to the binder mixture in the above-mentioned "binder mixture preparation step" to reduce the fluidity of the binder mixture.

In the present invention, the binder mixed solution is impregnated inside the nonwoven fabric as described above, and the obtained binder mixed solution-impregnated nonwoven fabric is inserted between a pair of rolls adjusted at a predetermined interval. It is desirable to set (adjust) the adhesion amount (impregnation amount) to a predetermined amount. Next, with respect to the “impregnating step of the binder mixed solution and the gas purging step”, an embodiment using various suitable impregnating machines in the step will be described in more detail with reference to the drawings.

<FIG. 1> In the present invention, for example, when the above-mentioned method is adopted, the roll-conveying impregnating machine 10 schematically shown in FIG. The above-mentioned impregnation step can be automated by successively performing the operations of “self-restoration-adhesion amount setting”.

The roll transport type impregnating machine 10 shown in FIG.
Are impregnating tanks 3 in which the binder mixture 2 is stored, sending rolls 7 and 8 provided outside the impregnating tank 3 for sending out the nonwoven fabric 1 to the impregnating tank 3, and the delivered nonwoven fabrics 1 in the impregnating tank 3. And a pair of squeezing / driving rolls 5 provided outside the impregnation tank 3 for adjusting the amount of the binder mixed liquid in the nonwoven fabric 1 that has passed through the impregnation tank 3.
6 is provided.

In this roll transport type impregnating machine 10, the nonwoven fabric 1 is guided into the impregnation tank 3 by the compression roll 4 via the sending rolls 7 and 8, and is immersed in the binder mixed solution 2 in the impregnation tank 3. While being held and stretched in tension by the delivery rolls 7, 8 and the compression roll 4 and the pair of upper and lower squeezing / driving rolls 5, 6, the compression roll 4 is pressed downward to receive compression. Is done.

At this time, the nonwoven fabric tension, compression surface pressure and the like are different depending on the material, production method, condition and the like of the nonwoven fabric and are not determined unconditionally. 10 to 40% of original substrate thickness
It is desirable to apply a load such that the thickness can be increased. Such conditions can be achieved by appropriately adjusting the rotation speed of these rolls, the mutual positional relationship between these rolls, and the like, and the amount of compression of the nonwoven fabric 1 by the compression rolls 4 can be appropriately adjusted.

(If the non-woven fabric 1 is excessively stretched when held in such a tensioned state, if it is excessively stretched, the belt-mesh transport impregnating machine 20 shown in FIG.
May be used. After passing through the compression roll 4, the nonwoven fabric 1 compressed by the compression roll 4 in the impregnation tank 3 is released from the pressure by the compression roll 4 and moves toward the upper and lower squeezing / driving rolls 5 and 6. In the spontaneous restoration process, the voids in the nonwoven fabric 1 become negative pressure, the binder mixture 2 in the impregnated layer is sucked into the voids, and the fibers between the spontaneously restored nonwoven fabrics become binders. The mixture 2 is filled (not shown). The nonwoven fabric 1 in which all the inter-fiber voids are filled with the binder mixed liquid as described above is sandwiched (inserted) by a pair of squeezing / driving rolls 5 and 6 provided outside the impregnation tank 3, and the nonwoven fabric 1 The amount of the binder mixed liquid impregnated and adhered to the substrate is adjusted to a predetermined range. Note that a plurality of such “belt-mesh transport impregnating machines” 20 may be installed in the vertical direction, or the like, and the process of impregnating the nonwoven fabric with the binder mixed liquid may be repeated a plurality of times.

In the above example, the case where the number of the compression rolls is one is shown. However, the present invention is not limited to such an embodiment.
For example, as shown by reference numeral 4a in FIG.
A compression roll may be provided below the nonwoven fabric 1 so as to form a pair, and the nonwoven fabric 1 may be compressed and pinched by the pair of compression rolls 4 and 4a. Also, a plurality of pairs of upper and lower compression rolls are provided in the impregnation tank 3 to “compress / release the nonwoven fabric”.
The “impregnation” may be repeated to increase the impregnation efficiency (not shown).

<FIG. 2> In the present invention, when the above-mentioned method (compression in liquid spontaneous restoration method) is adopted, the “nonwoven fabric” is conveyed by using a belt-conveying impregnating machine 20 schematically shown in FIG. The above-mentioned impregnation step can be automated by successively performing the operations of “compression—binder mixture impregnation—nonwoven fabric spontaneous restoration—adhesion amount setting”.

The belt transport type impregnating machine 20 shown in FIG.
Are impregnating tanks 3 in which the binder mixed liquid 2 is stored, upper and lower delivery rolls 25a and 26a provided outside the impregnating tank 3 to send out the nonwoven fabric 1 to the impregnating tank 3, and And a pair of upper and lower squeezing and driving rolls 5 and 6 that are provided outside and behind the impregnation tank 3 and adjust the amount of the binder mixture in the nonwoven fabric 1 that has passed through the impregnation tank 3. Have.

The belt transport type impregnating machine 20 is provided with two transport belts 21 and 22 which may be in the form of an endless track mesh. The upper transport belt 21 includes an upper delivery roll 25a and a compression roll 4 And the upper squeezing / driving roll 5, and a spontaneous restoration roll 25 b is provided between the compression roll 4 and the upper squeezing / driving roll 5.

The lower transport belt 22 is provided on the lower delivery roll 2
6a, the compression roll 4, and the lower squeezing / driving roll 6, and auxiliary rolls 26c, 26b are provided between the lower squeezing / driving roll 6 and the lower sending roll 26a. Belt transport type impregnating machine 2 having such a configuration
0, the upper conveying belt 21
The inner surface of the lower transfer belt 22 is in circumferential contact with the outer surface of the upper transfer belt 21 which is in circumferential contact with the compression roll 4 and the outer surface of the lower transfer belt 22 is in tight contact with the outer surface of the lower transfer belt 22.

The belt conveyer impregnating machine 20 having the above configuration
Then, the nonwoven fabric 1 is pinched and guided by the upper and lower transport belts 21 and 22 between the upper and lower delivery rolls 25a and 26a,
It is guided into the impregnation tank 3 where the compression rolls 4 are present, is immersed in the binder mixture 2 in the impregnation tank 3, and is nipped and compressed by the upper and lower transport belts 21 and 22 below the compression belt 4. The rotation speed of the compression roll 4 and the lower transport belt 22
By appropriately adjusting the tension and the like, the compression surface pressure, the amount of compression of the nonwoven fabric 1 by the four portions of the compression rolls, the compression time, and the like can be appropriately adjusted in the same manner as described above.

The strength of the non-woven fabric 1 used, especially the tensile strength, is not very high, and if the non-woven fabric 1 is stretched by using the impregnating machine 10 as shown in FIG. If the non-woven fabric 1 is conveyed while being sandwiched between 21 and 22, the belt non-woven fabric 1 will not be excessively stretched. An impregnation machine 20 can be used.

<FIG. 3> In the present invention, when the above-mentioned method (high-pressure spraying method) is adopted, a mesh-shaped base 31 is used by using a high-pressure spray impregnator 30 schematically shown in FIG.
The binder mixed liquid 1a is sprayed onto the surface of the non-woven fabric 1 below from above the non-woven fabric 1 placed thereon,
By continuously changing the relative position between the nonwoven fabric 1 and the spray nozzle 32a, it is possible to automate the impregnation step.

In order to change the relative position between the nonwoven fabric 1 and the spray nozzle 32a, (a): the position of the spray nozzle 32a is fixed, and the nonwoven fabric 1 on the mesh base 31 and the mesh base 31 are fixed. Or (b): the mesh base 31 and the nonwoven fabric 1 on the base 31 may be fixed, and the spray nozzle 32a may be moved. : Sprayer nozzle 32a and nonwoven fabric 1
May be moved in mutually different directions.

As described above, the non-woven fabric 1 is placed on the mesh base 31 and the binder mixed solution is sprayed from above onto the surface of the non-woven fabric 1 so that the binder mixed solution can be uniformly and evenly spread inside the non-woven fabric. It is possible to sufficiently permeate (impregnate). The conditions for efficiently impregnating the nonwoven fabric 1 with the binder mixed solution by the high-pressure spraying method thus vary depending on the moving speed of the nonwoven fabric, the spraying time, the distance from the nozzle to the nonwoven fabric, etc., and are not determined unconditionally.
For example, the above conditions can be set so that the required amount of impregnation is sprayed 10 to 50 times.

FIG. 4 shows an embodiment in which a suction device 33 is provided below the mesh base 31 in the high-pressure spray impregnator 30 shown in FIG. As shown in FIG. 4, if a suction device 33 is provided below the mesh-shaped base 31 to decompress and suction the gas and the like in the nonwoven fabric 1, the permeation (impregnation) efficiency of the binder mixed solution 1 can be further increased. it can.

Each of these impregnating machines 10, 20, 30,
Even when 30A is used, in order to uniformly impregnate the binder mixed solution 2 into the nonwoven fabric 1, the binder mixed solution is impregnated into the nonwoven fabric in a predetermined amount or more, and then, as shown in FIGS. As shown by numerals 5 and 6, it is desirable to insert between a pair of rolls adjusted at a predetermined interval.
By using the impregnating machine described in the above embodiment, the inside of the nonwoven fabric can be uniformly and completely impregnated with the binder mixed liquid, and a sheet-like sealing material excellent in gas and liquid sealing properties can be obtained. Is not limited to the embodiment using such an impregnating machine, the above-mentioned "pre-compressed liquid spontaneous restoration method", "compression in liquid spontaneous restoration method", "high pressure spray method"
As long as the method employs a "reduced pressure injection method and a reduced pressure replacement method", the present invention can be preferably used.

In the present invention, as described above, the binder mixed solution is impregnated into the nonwoven fabric, and gas such as air existing in the voids inside the nonwoven fabric is forcibly and substantially completely expelled. After the portion was replaced and filled with the binder mixed solution, the sheet was dried in the following “drying step” to obtain a sheet-like sealing material. <Drying Step (Step 3)> The nonwoven fabric after the above-mentioned “impregnation step of binder mixed solution and gas expelling step” (also simply referred to as “impregnation step”) has a solvent unnecessary for the sheet-shaped sealing material as a final product. Alternatively, a dispersion medium is included. If the rubber component is crosslinked or the resin component is cured in this state, the solvent or the dispersion medium remains in the sheet-shaped sealing material, and the sheet-shaped sealing material cannot exhibit stable sealing performance. Therefore, in the nonwoven fabric impregnated with the binder mixed solution, the solvent or the dispersion medium is removed from the nonwoven fabric after the completion of the impregnation process before performing the drying process described below.

The removal of the solvent or the dispersion medium is carried out at 80 ° C. or higher.
Desirably, in a dryer set at 80 ° C. or higher and 100 ° C. or lower, by heating the sheet for about 1 to 3 hours,
What is necessary is just to volatilize and remove a solvent or a dispersion medium. When the sheet is dried at a high temperature exceeding 100 ° C., the solvent or the dispersion medium in the nonwoven fabric may be rapidly vaporized and expanded, and voids may be generated inside the nonwoven fabric. When the drying step is performed at such a temperature exceeding 100 ° C., the following “forming step”
Since the crosslinking of the rubber in the sheet and the curing of the resin are promoted before performing the above, the effect of improving the airtightness by compression may not be sufficiently obtained in the following “molding step”. 80 ℃
When the sheet is dried at a temperature lower than the above, it takes a long time to completely volatilize and remove the solvent or the dispersion medium, which is inefficient.

The evaporation of the solvent or the dispersion medium mainly occurs on the surface of the sheet, and the solvent or the dispersion medium remaining inside the sheet moves to the surface. Removed. At that time, not only the solvent or the dispersion medium, but also the binder mixture itself in the sheet may be guided to the sheet surface (also referred to as migration).

By performing the following “forming step” on the sheet in which such migration has occurred, the rubber compounding ratio inside the sheet is reduced as compared with the rubber compounding ratio near the sheet surface. The sheet-like sealing material may not show sufficiently excellent sealing performance and stress relaxation performance. In such a case, as described above, a thermosensitive gelling agent (thermosensitive agent) is blended at the time of preparing the binder mixture in the “preparing the binder mixture” step (step 1), and the “drying step” is performed. By heating at a temperature equal to or lower than the drying temperature of the solvent or the dispersion medium, preferably at a temperature of 40 to 80 ° C., it is effective to increase the viscosity of the binder mixture and reduce the fluidity of the solid content. (Also referred to as "pre-drying step").

After the pre-drying step is performed as described above, the solvent or the dispersion medium is volatilized by heating the sheet in a dryer set at 80 ° C. or higher, preferably 80 ° C. to 100 ° C., as described above. -When removed, the resulting sheet-shaped sealing material has a uniform component content irrespective of its location, such as inside or near the surface, and tends to produce a well-balanced sheet-shaped sealing material with good sealing properties and stress relaxation properties. is there.

In the present invention, instead of the pre-drying step in which the heat-sensitive agent is mixed as described above, heating in a moist heat atmosphere is an effective method for suppressing migration. It is possible to increase the viscosity of the binder mixture inside the sheet and reduce the fluidity of the solid content without involving the movement or volatilization of the solvent or the dispersion medium. Heating in such a moist heat atmosphere is performed by heating the sheet for about 5 to 20 minutes in a steam atmosphere (humidity: 80 to 100%) at a temperature of 100 to 150 ° C., preferably 120 to 130 ° C. Done.

In the present invention, after heating in a moist heat atmosphere as described above, as described above, the temperature is 80 ° C. or higher, preferably 8 ° C.
"Drying process" in which the sheet is heated in a dryer set at 0 ° C or higher and 100 ° C or lower to evaporate and remove the solvent or dispersion medium.
May be performed. <Molding Step (Step 4)> In the present invention, the dried product (sheet) obtained through the above-mentioned drying step is pressurized under heating in this “forming step”, whereby the sheet is airtight after the drying step. In addition to improving the properties, crosslinking of the compounded rubber or curing of the resin is performed.

As a molding apparatus, a hot press is usually used. The molding conditions vary depending on the composition of the components and the like, and are not determined unconditionally.
0 ° C, heating time 3-15 minutes, compression surface pressure 5-40MPa
Is set as appropriate within the range. When vulcanization or curing by hot pressing is insufficient, the above-described rubber vulcanization or resin curing can be more effectively promoted by performing secondary heating under dry heat or wet heat. Such secondary heating is performed under the following conditions. That is, usually, the heating temperature is 150 to 250 ° C., and the heating time is 0.5 to 24.
What is necessary is just to hold | maintain under time, dry heat, or wet heat. In the case of secondary vulcanization, usually, free baking is often employed without applying a surface pressure.

A rubber material or resin as an organic binder is added to the sheet-like sealing material thus obtained.
Usually, 5 to 40% by weight, preferably 10 to 30% by weight, the base fiber constituting the nonwoven fabric is usually 5 to 80% by weight, preferably 10 to 70% by weight, more preferably 10 to 50% by weight. If necessary, the filler is contained in an amount of 0 to 80% by weight, especially when the filler is blended, preferably in an amount of 5 to 80% by weight, more preferably 30 to 80% by weight.
Desirably, it is included in an amount of weight percent.

The sheet-like sealing material thus obtained can maintain excellent gas-sealing properties and liquid-sealing properties at a high temperature for a long period of time, and has no strength anisotropy of the sealing material.

[0073]

According to the method for manufacturing a sheet-like sealing material of the present invention, the following effects can be obtained. (1) In the method for producing a sheet-shaped sealing material of the present invention, there is no limitation on the fibers that can be used, and a nonwoven fabric composed of a wide variety of fibers can be used. That is, unlike the conventional calender roll manufacturing method, in the present invention, after the nonwoven fabric is impregnated with the binder mixture and the gas inside the nonwoven fabric is completely removed, the nonwoven fabric is dried and heated or heated and compressed, so that the molding is performed. No shear stress is generated on the surface of the sheet-shaped sealing material, and wrinkles and breakage do not occur during molding even under the mixing condition of poor wettability between the fiber and the binder.
For this reason, there is no limitation on the fibers that can be used in the production method, and it is possible to produce a sheet-like sealing material containing rubber or resin that does not contain any p-aramid fibers.

(2) Since the sheet-like sealing material obtained by the production method of the present invention is hardly cured by use under high-temperature conditions, it can maintain excellent sealing performance and the like for a long time and has excellent long-term soundness. I have. Unlike the conventional joint sheet and beater sheet, the sheet-like sealing material obtained by the production method of the present invention uses a nonwoven fabric, whereby the entanglement between fibers, which is a strength factor, can be given in advance. Even if the fiber mixing ratio is set low, it is possible to reduce the influence of the curing of the rubber or resin itself on the curing of the sheet. When a rubber latex or a resin emulsion is used alone or in combination as a binder, the binder component is dispersed in the binder mixture. In the process of impregnating the nonwoven fabric with the binder mixture, drying and molding, the binder component inside the sealing material is kept in a dispersed state. In other words, since the binder component exists in a discontinuous state inside the sealing material, when used under high-temperature conditions, even if curing occurs in the dispersed particles of the binder component, this hardens and cures the sheet-shaped sealing material. Does not induce contraction. Further, in the present production method, any of a solution rubber, a liquid rubber, and a solution resin can be used in addition to the aqueous latex rubber latex or the resin emulsion.

(3) In the method for manufacturing a sheet-like sealing material according to the present invention, it is possible to reduce the strength anisotropy of the sheet, which is one of the causes of cracking under high temperature use. This is because fibers that have been formed into a nonwoven fabric in advance are used as a nonwoven fabric for forming a sealing material, and the fibers have no orientation at the stage of the nonwoven fabric. (4) The sheet-shaped sealing material manufactured by the present method has excellent airtightness. Nonwoven fabric is a material that originally contains many voids,
Therefore, it is possible to uniformly impregnate the inside of the nonwoven fabric with the binder mixed solution. A highly airtight sheet-like sealing material can be obtained by molding while holding the binder mixture once impregnated inside the nonwoven fabric.

[0076]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to such examples. The method of measuring the “elongation at break after thermal history”, which indicates the degree of curing of the sheet material used in the following Examples and Comparative Examples, is as follows.

<Elongation at Break after Thermal History> As a numerical value representing the degree of curing of the sheet material, the elongation at break by a tensile test after thermal history under predetermined conditions was measured. In consideration of the application to the tensile test, a 1.5 mm thick, 150 × 25 mm strip-shaped test piece was prepared, and the test piece was treated in heated air at 180 ° C. for 96 hours.
m, the elongation at break was measured by performing a tensile test at a tensile speed of 5 mm / min, and the elongation at break ( _RT ) was calculated by the following equation.

R _T = D _L− 100 (%) R _T : Elongation at break (%) D _L : Dimension between tensile jigs at break (mm)

[0079]

[Example 1] NBR latex was added at a solid content of 16k.
g, calcium carbonate 32 kg, powdered sulfur 0.2 kg,
0.2 kg of powdered zinc white, 1.3 kg of surfactant in solid weight, 0.4 kg of heat sensitive agent in solid weight, and 0.3 kg of thickener in solid weight were mixed with water 32. A binder mixture was prepared by diluting with 0.5 liter.

13 kg of needle punch felt produced using pitch-based carbon fiber was immersed in the binder mixture in a state of being compressed in advance, and spontaneously restored during the immersion of the binder mixture to impregnate. The impregnation operation was repeated three times to impregnate the entire binder mixture. This was placed in an electric furnace and heated at 50 ° C. for 30 minutes and at 90 ° C. for 90 minutes. Next, this was compressed at a surface pressure of 16 MPa for 10 minutes by a press vulcanizer set at 150 ° C. to produce a sheet-like sealing material.

The tensile strength (J
(ISR 3453 compliant) in the high strength direction (vertical direction, a)
20.8MPa, 2 in the low strength direction (lateral direction, b)
The strength anisotropy (a / b) was 1.0 MPa. In addition, room temperature sealability (based on ASTM F37-B. Surface pressure 19.6 MPa, nitrogen internal pressure 0.98 MPa)
Is 9.1E-5 (= 9.1 × 10 ⁻⁵ ) (Pa · m ³ /
s), and the elongation at break (% (lower of the values in the longitudinal and transverse directions)) after thermal history is 0.99%, which is the value until the occurrence of cracks when incorporated in an actual machine line and maintained at 230 ° C. The number of days was over 360 days.

The amounts of the components and the test results are shown in Table 1.

[0083]

[Example 2] NBR latex was added at a solid content of 16k.
g, calcium carbonate 32 kg, powdered sulfur 0.2 kg,
0.2 kg of powdered zinc white, 1.3 kg of surfactant in solid weight, 0.4 kg of heat sensitive agent in solid weight, and 0.3 kg of thickener in solid weight were mixed with water 32. A binder mixture was prepared by diluting with 0.5 liter.

22 kg of needle punch felt produced using pitch-based carbon fiber was immersed in the binder mixture in a state of being compressed in advance, spontaneously restored in the binder mixture immersion, and all the binder mixture was impregnated. This was placed in an electric furnace, and was heated at 50 ° C. for 30 minutes and 90 ° C. for 90 minutes.
Heated for minutes. This was compressed by a press vulcanizer set at 150 ° C. at a surface pressure of 16 MPa for 10 minutes to produce a sheet-like sealing material.

The tensile strength (J
(ISR 3453 compliant) in the high strength direction (vertical direction, a)
25.3MPa, 2 in the low strength direction (lateral direction, b)
It was 2.8 MPa, and the strength anisotropy (a / b) was 1.1. In addition, room temperature sealability (based on ASTM F37-B. Surface pressure 19.6 MPa, nitrogen internal pressure 0.98 MPa)
Is 7.5E-5 (Pa · m ³ / s), and the elongation at break after thermal history (% (lower value of values in the longitudinal and transverse directions)) is 0.80%. Embedded in 2
When maintained at 30 ° C., the number of days until crack generation is 360
Days or more.

The amounts of the components and the test results are shown in Table 1.

[0087]

Example 3 NBR latex is 16k by solid weight
g, calcium carbonate 96 kg, powdered sulfur 0.2 kg,
Mix 9 kg of powdered zinc white, 1 kg of surfactant in solid weight, 0.4 kg of heat sensitive agent in solid weight, 0.5 kg of thickener in solid weight, and mix with 96.5 water. By diluting with liter, a binder mixture was prepared.

Next, an impregnation step, a drying step, and a molding step were performed in the same manner as in Example 1 except that 8 kg of a needle punch felt produced using p-aramid fiber was used to produce a sheet-like sealing material. The tensile strength (according to JIS R 3453) of the obtained sheet-like sealing material was 26.3 MPa in the high strength direction (longitudinal direction, a) and 23.1 MPa in the low strength direction (horizontal direction, b). The anisotropy (a / b) was 1.1. In addition, room temperature sealability (based on ASTM F37-B; surface pressure of 19.6 MPa,
Nitrogen internal pressure 0.98 MPa) is 8.4E-5 (Pa · m
³ / s), and the elongation at break (% (lower of the values in the longitudinal and transverse directions)) after heat history is 3.00%, and cracking occurs when the device is incorporated in an actual machine line and maintained at 230 ° C. The number of days until now was 360 days or more.

The amounts of the components and the test results are shown in Table 1.

[0090]

[Reference Example 1] NBR latex is 3k by solid weight.
g, 96 kg of calcium carbonate, 0.1 kg of powdered sulfur,
0.1 kg of powdered zinc white, 0.4 kg of surfactant in solid weight, 0.16 kg of heat sensitive agent in solid weight, and 0.2 kg of thickener in solid weight are mixed with 96 parts of water. A binder mixture was prepared by diluting with 0.5 liter.

Next, an impregnation step, a drying step and a molding step were carried out in the same manner as in Example 1 except that 7.5 kg of needle punch felt produced using p-aramid fiber was used to produce a sheet-like sealing material. did. Tensile strength of the obtained sheet-like sealing material (based on JIS R 3453)
Was 7.5 MPa in the high strength direction (vertical direction, a), 7.2 MPa in the low strength direction (horizontal direction, b), and the strength anisotropy (a / b) was 1.0. In addition, room temperature sealability (based on ASTM F37-B; surface pressure of 19.6 MPa,
Nitrogen internal pressure 0.98MPa) is 2.5E-3 (Pa ・ m
³ / s), and the elongation at break (% (lower of the values in the longitudinal and transverse directions)) at break after thermal history is 0.70%, and cracking occurs when it is incorporated in the actual machine line and maintained at 230 ° C. The number of days until now was 180 days.

The amounts of the components and the test results are shown in Table 1.

[0093]

Comparative Example 1 A composition for forming a joint sheet having the following composition was prepared. Fibrillated aromatic amide fiber 10.8% by weight NBR 15.9% by weight Rubber chemicals 2.3% by weight Inorganic filler (heavy carbon, clay) 71.0% by weight Toluene 0.7 liter per 1 kg of the above mixture The obtained composition was heated at 30 ° C with a hot roll maintained at 130 ° C.
And rolled by heating.
In this way, the composition was formed into a sheet-like viscous layer on the hot roll side. The sheet was peeled off from the hot roll with a doctor blade to obtain a 1.5 mm thick joint sheet.

The tensile strength of the obtained joint sheet (J
(ISR 3453 compliant) in the high strength direction (vertical direction, a)
42.7 MPa, 1 in the low strength direction (lateral direction, b)
7.1 MPa, and the strength anisotropy (a / b) was 2.5. In addition, room temperature sealability (based on ASTM F37-B. Surface pressure 19.6 MPa, nitrogen internal pressure 0.98 MPa)
Is 3.1E-4 (Pa · m ³ / s), the elongation at break after heat history (% (lower value in the longitudinal and lateral directions)) is 0.25%, and the actual machine line Embedded in 2
When kept at 30 ° C., the number of days until crack generation is 120
The day has come.

The amounts of the components and the test results are shown in Table 1.

[0096]

Comparative Example 2 A composition for forming a joint sheet having the following composition was prepared. Asbestos fiber 75.3% by weight SBR 12.5% by weight Rubber chemicals 3.2% by weight Inorganic filler (clay) 9.0% by weight Toluene The above composition obtained in a ratio of 0.7 L per 1 kg of the above mixture A joint sheet was obtained in the same manner as in Comparative Example 1 except for using.

The tensile strength of the obtained joint sheet (J
(ISR 3453 compliant) in the high strength direction (vertical direction, a)
82.4MPa in the low strength direction (lateral direction, b)
0.6 MPa, and the strength anisotropy (a / b) was 2.7. In addition, room temperature sealability (based on ASTM F37-B. Surface pressure 19.6 MPa, nitrogen internal pressure 0.98 MPa)
Is 1.7E-3 (Pa · m ³ / s), the elongation at break after thermal history (% (lower value in the longitudinal and transverse directions)) is 1.02%, and the actual machine line Embedded in 2
When maintained at 30 ° C., the number of days until crack generation is 360
Days or more.

The amounts of the components and the test results are shown in Table 1.

[0099]

Comparative Example 3 An aqueous dispersion slurry having the following composition was prepared. Ceramic fiber 14% by weight Cellulose fiber 5% by weight Rock wool fiber 14% by weight Inorganic filler (clay) 59% by weight NBR latex 8% by weight The obtained composition is formed by a round-mesh type paper machine, and then dried and pressed. Thus, a beater sheet was obtained.

The tensile strength of the obtained beater sheet (JI
SR 3453) is 36.2 MPa in the high-strength direction (vertical direction, a) and 1 in the low-strength direction (horizontal direction, b).
2.7 MPa, and the strength anisotropy (a / b) was 2.9. In addition, room temperature sealability (based on ASTM F37-B. Surface pressure 19.6 MPa, nitrogen internal pressure 0.98 MPa)
Was 6.3E-2 (Pa · m ³ / s).

The amounts of the components and the test results are shown in Table 1.

[0102]

[Table 1]

From the above Examples, Reference Examples and Comparative Examples, it can be seen that in the production method of the present invention, there is no limitation on the fiber type of the nonwoven fabric to be the nonwoven fabric. (A) According to the production method of the present invention, not only p-aramid fiber but also sheet-like sealing material using carbon fiber or glass fiber as the sole fiber type, which is usually difficult in a joint sheet by calender roll performance, It can be manufactured.

According to the production method of the present invention, ceramic fibers, mineral fibers, PPS fibers, m
-A sheet-shaped sealing material using only an organic fiber such as aramid fiber as the only fiber type, and a sheet-shaped sealing material obtained by mixing PPS fiber and ceramic fiber could be produced. (B) The sheet-like sealing material obtained by the production method of the present invention has a higher degree of curing under high-temperature conditions than the non-asbestos joint sheet produced by the conventional production method, based on the results of “elongation at break after thermal history”. It can be seen that the degree has been reduced. (C) According to the production method of the present invention, it can be seen that a sheet-like sealing material with improved strength anisotropy of the sheet-like sealing material can be obtained.

Tensile strength under normal conditions (JIS R 3453)
If the value (a / b) obtained by dividing the value a in the vertical direction by the value b in the horizontal direction (a / b) is regarded as the strength anisotropy, it is understood that the material has extremely high two-dimensional isotropy. (D) It can be seen that a highly airtight sheet-like sealing material can be manufactured by the manufacturing method of the present invention.

As compared with the sealing performance of the beater sheet obtained by the conventional method, the sealing performance of the sheet-shaped sealing material of the present invention has sufficient sealing performance as a sheet-shaped sealing material for gas sealing. You can see that there is. (E) According to the production method of the present invention, it has become possible to produce a sheet-like sealing material that is less likely to crack.

As described above, according to the method for producing a sheet-like sealing material according to the present invention, there is no limitation on the fiber type and excellent heat-curing resistance, which could not be achieved by the existing joint sheet production method and beater sheet production method. Further, it can be seen that a sheet-like sealing material excellent in crack resistance, low-strength anisotropy, and high airtightness with long-term use at high temperature can be obtained.

[Brief description of the drawings]

FIG. 1 is a roll transport type impregnating machine preferably used in one embodiment of the present invention and capable of continuously performing operations of nonwoven fabric compression, impregnation of a binder mixed solution, spontaneous restoration of a nonwoven fabric, and setting of an attached amount. FIG.

FIG. 2 is a diagram illustrating the continuous use of each operation of nonwoven fabric compression in a binder mixture, impregnation of a binder mixture, spontaneous restoration of a nonwoven fabric, and setting of an adhesion amount, which is preferably used in one embodiment of the present invention. FIG. 4 is a schematic explanatory view of a possible belt transport type impregnating machine.

FIG. 3 is a schematic explanatory view of a high-pressure spray impregnating machine preferably used in one embodiment of the present invention.

FIG. 4 shows the high-pressure spray impregnator shown in FIG.
It is a figure which shows the aspect which provided the suction device below the mesh-shaped base.

[Explanation of symbols]

1 ···· Non-woven fabric 1a, 2 ···· Binder mixed liquid 3 ················ Impregnation tank 4 ············ (Top) Compression roll 4a (Lower) compression rolls 5, 6 ... squeezing / driving rolls 7, 8, ... delivery rolls 10 ... roll transport type impregnating machine 20 ... belt / mesh transport Type impregnating machine 21, 22 .... Conveyor belt 25a, 26a ..... Up and down delivery roll 25b ..... Spontaneous restoration roll 26b, 26c ..... Auxiliary roll 30 ... High-pressure spray impregnator 30A ... High-pressure spray impregnator 31 ... Mesh base 32a ... Spray nozzle 33 ... Suction device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Asahina 6-6-6 Ginza, Chuo-ku, Tokyo Inside the Tokyo Works of Nippon Balcar Industry Co., Ltd. Road 150 Nippon Valqua Industry Co., Ltd. Shinshiro Plant (72) Inventor Kiyoto Takata 5-5-5 Annakacho, Yao-shi, Osaka Japan Valqua Industry Co., Ltd. Seal Business Dept. (72) Inventor Black Shinya Kawa 5-5-5 Annakacho, Yao-shi, Osaka Japan F-term in the Research and Development Department, Seal Division, Valqua Industry Co., Ltd. 3J040 EA16 FA05 FA20 HA01 4L033 AB07 CA68 CA69 CA70 4L047 AA03 AA24 AB02 BA03 BA16 BC02 BC14 CB01 CB10 CC14

Claims (9)

[Claims] 1. A rubber material as an organic binder, a rubber chemical, and a solvent or a dispersion medium for the rubber material are mixed. To expel and impregnate the gas present in the mixed solution, volatilize and remove at least a part of the solvent or dispersion medium from the non-woven fabric impregnated with the mixed solution, and then heat-press the non-woven fabric to vulcanize the rubber material. A method for producing a sheet-like sealing material, comprising obtaining a sheet-like sealing material. 2. The method according to claim 1, wherein the binder mixture is used in the form of a latex. 3. A resin as an organic binder and a solvent or a dispersion medium for the resin are mixed, and the obtained binder mixed solution is expelled into a non-woven fabric composed of base fibers to expel gas present inside the non-woven fabric. At least a part of the solvent or the dispersion medium is volatilized and removed from the non-woven fabric impregnated with the mixed solution, and then the non-woven fabric is heated and compressed, and the resin is cured to obtain a sheet-like sealing material. A method for producing a sheet-shaped sealing material. 4. The method according to claim 1, wherein the base fiber is a non-asbestos fiber. 5. The method according to claim 1, wherein the nonwoven fabric is in a felt form. 6. The method according to claim 1, wherein the binder mixture contains a filler. 7. The step of purging gas present inside the nonwoven fabric and impregnating with the binder mixed solution may be performed by immersing the nonwoven fabric in the binder mixed solution while compressing the nonwoven fabric in advance, or by compressing the nonwoven fabric in the binder mixed solution. The method according to any one of claims 1 to 6, wherein the reaction is carried out by spontaneous restoration in a binder mixture. 8. The non-woven fabric according to claim 1, wherein the step of expelling gas present inside the non-woven fabric and impregnating the non-woven fabric with the binder mixed solution is performed by spraying the binder mixed solution onto the non-woven fabric under high pressure. the method of. 9. The method of purging gas present inside the nonwoven fabric and impregnating with the binder mixed solution is performed by putting the nonwoven fabric in a reduced-pressure container, reducing the pressure inside the container, and then injecting the binder mixed solution. The method according to any one of claims 1 to 6.