JP2003277727A - Preparation process for sheet sealing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet sealing material having an excellent stress relaxation property. <P>SOLUTION: In this process, a sheet sealing material is obtained by mixing (a) an organic binder comprising a rubber material and a thermosetting resin and containing 5-30 wt.% of the thermosetting resin, (b) a chemical agent for the rubber (and optionally a chemical agent for the resin) and (c) a solvent for the rubber, a solvent for the resin or a dispersion medium, impregnating the obtained compound into a nonwoven fabric comprising base fibers while driving out the gas contained in the nonwoven fabric, evaporating and removing at least a part of the solvent or the dispersion medium from the mixture-liquid- impregnated nonwoven fabric and heat-pressing the nonwoven fabric to vulcanize the rubber material and cure the thermosetting resin. <P>COPYRIGHT: (C)2004,JPO

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-shaped sealing material, and more particularly to a method for manufacturing a sheet-shaped sealing material having excellent stress relaxation characteristics.

[0002]

BACKGROUND OF THE INVENTION At present, various types of gaskets are used for general industries, but the most versatile one is a joint sheet mainly composed of fiber and filler and rubber or resin. Alternatively, a beater sheet may be used. Here, the joint sheet is asbestos, inorganic fibers such as glass fibers, or organic fibers such as aromatic polyamide fibers, fibrillated aromatic polyamide fibers as a base fiber, rubber or resin as a binder, a rubber A vulcanizing agent or the like as a chemical, and a filler or the like are added and kneaded to prepare a composition for forming a joint sheet, which is inserted between a pair of rolls composed of a heat roll and a cooling roll and heated and rolled. It is obtained by stacking the joint sheet molding composition on the hot roll side and then peeling off the sheet-shaped product laminated on the hot roll.

A beater sheet is obtained by adding a filler and rubber or resin to asbestos fibers or non-asbestos fibers in a beating machine, agitating them to uniformly disperse them in water, and then making paper by a paper making machine. . These sheets are relatively inexpensive, easy to produce large-sized products, easy to process into various shapes, easy to handle, and capable of sealing fluid even with relatively low tightening force. It has various features such as being capable. However, there are problems with these joint sheets and beater sheets.

As the first problem of the joint sheet,
There are restrictions on the fibers that can be used in the manufacturing process. In the production of a joint sheet, the wettability between the raw material fibers and the rubber or resin is important, and if the wettability is poor, wrinkles or breaks will occur in the sheet during sheet formation. Currently, there are asbestos joint sheets containing asbestos fibers that have good wettability with rubber or resin, and non-asbestos joint sheets that do not contain asbestos fibers (non-asbestos joint sheets), but they have poor wettability with rubber. There are very few joint sheets that use carbon fiber or the like, which is said to be the sole fiber species, and most non-asbestos joint sheets on the market contain a small amount of p-aramid fiber. The limitation on the usable fiber type is a great limitation in improving the quality of the gasket material.

The second problem is the regulation of use of asbestos fibers. Asbestos joint sheet is an excellent product because it can maintain excellent properties for a long time at high temperature, can be used for various fluids at various temperatures, and has high versatility, but asbestos fiber itself , The use of asbestos joint sheets is being replaced by other gaskets.

As a third problem, the non-asbestos joint sheet has, for example, sealing property, tensile strength, stress relaxation rate, etc. when used in an actual machine at high temperature for a long period of time as compared with the asbestos joint sheet. It is inferior in the property of retaining excellent performance (also called "long-term soundness"). This is because the non-asbestos sheet is apt to be cured by the history of high temperature air.

In the case of an asbestos joint sheet, by setting a high compounding ratio of the asbestos fiber which bears strength, it is possible to reduce the influence of the curing of the compounded rubber or resin 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 added as a strength improver, but the fiber has poor wettability and the strength of the sheet is increased even if a large amount of p-aramid fiber is added. Rather, other properties and processability are often deteriorated, and it is difficult to mix a large amount of the fiber, and as a result, curing of the rubber or resin itself leads to curing of the entire sheet.

A fourth problem is that the joint sheet cannot eliminate the strength anisotropy of the sheet due to the manufacturing method. This is because the fibers to be blended are oriented almost uniformly by going through the compression vulcanization step using the calender rolls. In the case of an asbestos joint sheet, the strength of the entire sheet can be remarkably increased by setting the compounding ratio of the asbestos fiber to a high level, whereby the above strength anisotropy can be complemented.

On the other hand, in the case of a non-asbestos joint sheet, its fiber blending ratio cannot be set high, and the fibers to be blended cannot complement the above-mentioned strength anisotropy. Therefore, when stress is generated inside the gasket due to hardening of the rubber component during long-term use at high temperature, it is presumed that the stress concentrates in the weaker direction or in that part, and as a result, gasket cracking is induced. It

On the other hand, the beater sheet has a problem in terms of airtightness. Generally, the beater sheet is used for sealing liquids such as lubricating oil and fuel oil, and specifically used for oil pans, fuel pumps and the like. On the other hand, it is not used as a gasket such as a gaseous fluid that requires strict airtightness. Regarding the gaskets obtained by the beater sheet manufacturing method currently on the market, "ASTM
According to "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 gasket outer diameter part was measured to be 6.3 × 10 ^-2
Pa · m ³ / s was shown. It is considered that the reason for the large amount of gas leakage is that a part of the voids included in the sheet in the papermaking process remains without being removed during the manufacturing process. Under actual use conditions, the soap water foaming method is generally used to determine the presence or absence of leakage of the gaseous fluid from the gasket. In this soap water foaming method, the actual equipment (gas fluid piping) is used.
After mounting the test gasket on the flange and applying soap water on the gasket outer diameter side or flange gap, check whether the gaseous fluid is leaking from the connection part of the gaseous fluid piping due to the presence or absence of bubbles. To judge. The detection sensitivity of this soapy-water foaming method is about 2 × 10 ⁻⁴ Pa · m ³ / s. Since the beater sheet generally shows a leak amount 18 to 550 times higher than the detection sensitivity of this soapy water foaming method,
The beater sheet has low sealing performance and is unsuitable as a sealing material for a gaseous fluid. 2 as a gas sealant
Sealing performance showing a leakage amount of × 10 ^-4 Pa · m ³ / s or less is required.

However, up to now, no sealing material has been known which is obtained by the beater sheet manufacturing method as described above and has an excellent gas sealing performance and the like. Therefore, the present inventors have conducted extensive studies in order to solve the above problems, mixing a rubber material as an organic binder, a rubber chemical, and the solvent or dispersion medium for the rubber material, or an organic material. A resin as a binder is mixed with the resin solvent or dispersion medium, and the resulting compound is impregnated into a non-woven fabric composed of base fibers while expelling (forced) the gas present inside the non-woven fabric. , At least a part of the solvent or dispersion medium is volatilized and removed from the non-woven fabric impregnated with the mixed liquid, and then the non-woven fabric is heated and compressed to vulcanize the rubber material or cure the resin to form a sheet. It has been found that when a sealing material is manufactured, a sheet-shaped sealing material in which the strength anisotropy is suppressed and the gas sealing property is remarkably excellent can be obtained. It was proposed as No. 85.

As a result of further studies, the organic binder (a) is composed of a rubber material and a thermosetting resin, and the compounding amount (ratio) of these is limited to a specific range. a), a chemical for rubber (and a chemical for resin if necessary) (b), and the solvent for the rubber material, the solvent for the resin or the dispersion medium (c) are mixed, and then the resulting compound is used to form a non-woven fabric The present invention has been completed by finding that a sheet-like sealing material having particularly excellent stress relaxation characteristics and exhibiting stable sealing performance for a long period of time can be obtained by the same treatment as described above.

In Japanese Patent Laid-Open No. 57-116970, one or more non-woven fabrics made of hydrophobic short fibers such as tetron and nylon are used as a base material, on which a resin or rubber is used. There is disclosed packing for food machine tools which is formed by impregnating a binder such as the above. Also,
The publication describes that the base material is impregnated with a binder such as resin or rubber and dried, and then pressure-molded to produce the packing for food machine tools. Further, the publication describes that this packing has excellent sealing properties and is hygienic. However, since the impregnation step included in this publication is resin impregnation for the purpose of preventing fiber scattering and packing corrosion, the packing obtained by the method described in this publication is a packing material that strictly limits leakage. It is insufficient to be used in terms of sealing properties such as gas and liquid.

Further, in Japanese Patent Publication No. 8-3086, the colloidal particles of silicone resin or the polytetrafluoroethylene resin and acrylic primer are dispersed in water to cause ignition and harmfulness due to volatilization. Of a water-dispersed emulsion free of water, impregnating the emulsion inside the entire needle mat formed by needle punching a cotton-like material mainly composed of glass fiber, By evaporating water, a silicone resin or 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 of manufacturing a packing material for a combustion appliance is disclosed. In addition, in this publication, a water-dispersed emulsion is stored in a dipping tank, and the needle mat is continuously fed to the emulsion by a roller feeding device.
It is described that the entire inside of the needle mat is impregnated with the emulsion by soaking for about 0 seconds. In addition, by using the above water-dispersed emulsion, it becomes possible for the first time to impregnate the entire inside of the needle mat with the emulsion, and the surface of all the glass fibers constituting the needle mat and the silicone resin between the fibers or It is described that a PTFE resin can be attached.

However, the method described in the publication does not include a compression molding step, and the airtightness of the packing is not improved, and the packing material for a combustion instrument obtained by the method described in the publication does not contain a gas. Alternatively, it is insufficient in terms of liquid sealing property.

[0016]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and in particular, is a sheet-like sealing material having excellent stress relaxation characteristics and capable of exhibiting stable sealing properties for a long period of time. Is intended to provide.

[0017]

SUMMARY OF THE INVENTION A method for producing a sheet-shaped sealing material according to the present invention comprises a rubber material and a thermosetting resin, preferably an organic binder containing the thermosetting resin in an amount of 5 to 30% by weight. (a), a chemical for rubber (and a chemical for resin if necessary) (b) and the solvent for rubber material, the solvent for resin or the dispersion medium (c) are mixed, and the obtained compound is used as a base fiber. The non-woven fabric (d) consisting of is driven out and impregnated with the gas present inside the non-woven fabric, and at least a part of the solvent or dispersion medium is volatilized and removed from the non-woven fabric impregnated with the compound, and then the non-woven fabric is heated and compressed. Then, the rubber material is vulcanized and the thermosetting resin is cured to obtain a sheet-shaped sealing material.

In a preferred embodiment of the present invention, it is desirable that the rubber component forming the compound is used in the form of latex and the resin component is used in the form of emulsion. In a preferred embodiment of the present invention, it is desirable that the rubber component forming the compound is used in the form of latex and the resin component is used in the form of aqueous solution.

In the present invention, the total solid content (nonvolatile component) in the compound and the nonwoven fabric (d) is 100.
5 to 40 wt% of the organic binder (a) in wt%
It is preferable that it is contained in the amount of. The sheet-shaped sealing material according to the present invention is characterized by being obtained by any of the above methods.

In the present invention, the base fibers are preferably non-asbestos fibers. In the present invention, the non-woven fabric is preferably in the form of felt. In the present invention, the compound preferably contains the filler (e). In the present invention, a step of expelling the gas present inside the nonwoven fabric and impregnating the compound,
It is preferable to immerse the non-woven fabric in the compound while compressing it in advance, or to compress the non-woven fabric in the compound and then spontaneously restore it in the compound.

In the present invention, the step of expelling the gas present inside the nonwoven fabric and impregnating the compound is preferably carried out by high-pressure spraying the compound onto the nonwoven fabric. In the present invention, the step of expelling the gas present inside the nonwoven fabric and impregnating the compound is preferably carried out by placing the nonwoven fabric in a decompression container, reducing the pressure inside the container, and then injecting the compound.

According to the method for producing a sheet-shaped sealing material of the present invention, it is possible to obtain a sheet-shaped sealing material which is particularly excellent in stress relaxation characteristics and can exhibit stable sealing performance for a long period of time.

[0023]

DETAILED DESCRIPTION OF THE INVENTION The method for producing a sheet-shaped sealing material according to the present invention will be specifically described below. In the method for producing a sheet-shaped sealing material according to the present invention, the sheet-shaped sealing material is made of a rubber material and a thermosetting resin, and the thermosetting resin is preferably 5 to 3
An organic binder (a) contained in an amount of 0% by weight, a chemical agent for rubber (and a chemical agent for resin if necessary) (b), and the solvent for rubber material, the solvent for resin or the dispersion medium (c). Mix and
The resulting compound (binder mixture) is impregnated into the nonwoven fabric (d) made of the base fiber while expelling the gas present inside the nonwoven fabric, and at least a part of the solvent or the solvent impregnated from the nonwoven fabric impregnated with the mixed solution. Volatilizes dispersion medium
After removal, the nonwoven fabric is heated and compressed to vulcanize the rubber material and cure the thermosetting resin to produce a sheet-shaped sealing material.

That is, in the sheet-like sealing material manufacturing method of the present invention, unlike the conventional calender roll manufacturing method which is a manufacturing method of a joint sheet, basically, a non-woven fabric is used as a base fiber, and a non-woven fabric. When impregnating a compound (binder mixed solution) into, the gas in the non-woven fabric is forcibly expelled so that there is no gas in the non-woven fabric filled with the compound. After impregnating the non-woven fabric with the compound and forcibly expelling the gas, the solvent component or the dispersion medium in the compound impregnated into the non-woven fabric is volatilized and removed, and then heat compression molding is performed to form the gas. It is possible to manufacture a sheet-shaped sealing material that has outstanding long-term sealing properties against liquids and has no strength anisotropy.

Particularly, in the present invention, in relation to the above-mentioned Japanese Patent Application No. 2000-296585 previously proposed by the present applicant, the organic binder (a) is composed of a rubber material and a thermosetting resin. Is contained in a specific weight ratio, the organic binder (a), relative to the total of the compound solids (a) and the nonwoven fabric (d), or
The organic binder is added to the sheet-like sealing material-forming non-volatile components such as (a) and (d) and optionally contained filler (e).
It is characterized by the fact that (a) is included in a specific amount.

The organic binder (a), a rubber chemical (and, if necessary, a resin chemical) (including a combination system of a rubber chemical and a resin chemical. The same applies hereinafter) (b) and the rubber A solvent for a material, a solvent for a resin or a dispersion medium (including a combination system of two or more of these; the same applies hereinafter) (c) is mixed, and then the obtained compound is used to form a non-woven fabric according to the above-mentioned Japanese Patent Application. If the same treatment as described in the specification of 2000-296585 is performed, it is possible to obtain an effect that a sheet-shaped sealing material which is particularly excellent in stress relaxation property and can exhibit stable sealing property for a long period of time can be manufactured.

The above compounds, non-woven fabrics, impregnation methods, etc. will be described in detail below. <Compound (Binder Mixture)> As the compound (also referred to as a binder mixture), a compound containing both a rubber material and a thermosetting resin as the organic binder contained as described above is used.

Explaining the composition of this mixed solution in detail, if only one rubber material is used as the organic binder, the amount of the binder component is reduced in order to obtain a sheet-shaped sealing material having excellent stress relaxation characteristics. It is effective to do.
However, when the amount of rubber decreases, the denseness of the sheet-shaped sealing material tends to be lowered, and the long-term stable sealing performance tends to be impaired.

On the other hand, in the present invention, since the thermosetting resin having higher heat resistance than the rubber material is used together with the rubber material, the stress relaxation property and the stress relaxation property can be obtained without reducing the total amount of the binder. A sheet-like sealing material having stable sealing performance for a long period of time has been obtained. This organic binder
The rubber material and the thermosetting resin are thus contained in (a), and the compound corresponding to the rubber material, which is one component of these organic binders, includes a rubber chemical in addition to this rubber material. A rubber material solvent or dispersion medium may be contained, and a filler or the like may be further contained if necessary. Further, in correspondence with the thermosetting resin which is the other component of the organic binder, the compound contains not only the thermosetting resin but also a solvent or dispersion medium for the resin and, if necessary, a chemical for the resin. Therefore, a filler or the like may be included.

The rubber material is not particularly limited and widely known materials can be widely used, for example, natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber,
Urethane rubber, chloroprene rubber, acrylonitrile butadiene rubber, butyl rubber, ethylene propylene rubber,
Acrylic rubbers, silicone rubbers, fluororubbers, and the like can be mentioned, and of these, styrene-butadiene-based, acrylonitrile-butadiene-based, and acrylate-based rubbers are preferable.

As these rubber materials, it is preferable to use rubber materials in a fluidized state, that is, in the form of a rubber solution, liquid rubber, rubber latex or the like, and one kind or a combination of two or more kinds may be used. In particular, when a latex type rubber material is used, the viscosity of the compound can be easily adjusted so that the filler can be easily dispersed. Examples of the thermosetting resin include epoxy resin, diallyl phthalate resin, phenol resin, polyimide resin, melamine resin, urea resin, and the like. Considering heat resistance and the like, even among these thermosetting resins, Is preferred. 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. The resin includes a thermoplastic resin in addition to the thermosetting resin, but the thermoplastic resin may soften the gasket depending on the usage conditions of the sheet-shaped gasket to be obtained. Not suitable for use.

Among these thermosetting resins, water-soluble or emulsion type resins are preferable because the viscosity can be easily adjusted and the compound having excellent dispersibility of the filler can be easily prepared. In the present invention, it is preferable that the rubber component forming the compound is used in the form of latex and the resin component is used in the form of aqueous solution or emulsion.

As the above-mentioned rubber chemicals (rubber chemicals), conventionally known ones can be widely used. For example, a vulcanizing agent, a vulcanization aid, an accelerator, an antiaging agent and the like, and if necessary, a thickening agent. , A heat-sensitive gelling agent (heat-sensitive agent), a surfactant and the like may be used. A curing agent, a modifier, a modifier and the like may be used as the above-mentioned resin chemicals used as necessary.

In the present invention, these rubber chemicals and resin chemicals may be used in combination. As the thickener, for example,
Examples thereof include polyvinyl alcohol-based, polyacrylic acid-based, polymethacrylic acid-based, polyacrylamide-based synthetic polymers and alginates thereof; natural and semi-synthetic polymers such as casein, gelatin, and guar gum.

The filler is used, if necessary, and contributes to the stress relaxation characteristics and the sealing performance of the sheet-shaped sealing material. Specific examples of such a filler include talc, mica, clay and oxidation. Inorganic powders such as magnesium and calcium carbonate can be used. In the present invention, these fillers are used alone or in combination of two or more.

As the solvent and the dispersion medium, conventionally known ones can be widely used, and examples thereof include acetone, methyl ethyl ketone, ethylene glycol, dimethylformamide, methyl alcohol, ethyl alcohol, ethyl acetate and water. 1 solvent or dispersion medium
They may be used alone or in combination of two or more. The manufacturing method is not limited.

The use of water as the solvent or dispersion medium has the advantage that the nonwoven fabric impregnated with the compound can be safely subjected to the drying step described later. In the present invention, the thermosetting resin is an organic binder (a), in other words, an organic binder composed of a rubber material and a thermosetting resin.
The content of (a) in the amount of 5 to 30% by weight, preferably 15 to 28% by weight, and particularly preferably 18 to 25% by weight is used as a sealing material having room temperature sealing characteristics, stress relaxation characteristics and the like. It is desirable in terms of characteristics balance.

The thermosetting resin is an organic binder.
If the amount in (a) is less than the above amount, a sealing material having excellent stress relaxation characteristics cannot be obtained. If the amount is more than the above amount, the rubber component which is an elastic component is too small, and the restoring force of the sheet decreases. Further, in the present invention, an organic binder
(a), that is, the rubber material and the thermosetting resin, the solid content (nonvolatile components) in the compound, and the nonwoven fabric (d)
When the total weight of and is 100% by weight, the total amount is usually 5 to 40% by weight, preferably 10 to 30% by weight.

If the total content of the rubber material serving as the binder (a) and the thermosetting resin is less than 5% by weight, the surface of the fibers constituting the non-woven fabric and the surface of the filler used if necessary cannot be sufficiently covered. Alternatively, the compound cannot be sufficiently filled in the voids inside the nonwoven fabric, and as a result, the sealing performance of the sheet-shaped sealing material may be deteriorated. On the other hand, when the content of the rubber material and / or the thermosetting resin exceeds 40% by weight, the component contained in the obtained sheet-shaped sealing material is likely to be hardened or contracted due to heat history, resulting in the sheet-shaped sealing material. In that case, curing and cracking due to heat history are likely to occur, and it may be difficult to maintain characteristics such as excellent gas sealability and liquid sealability for a long period of time.

When a filler is used in the present invention, the filler is usually 80% by weight or less, preferably 5 to 5% by weight based on 100% by weight of the solid content in the compound and the nonwoven fabric.
Used in an amount of 80% by weight. If the content of the filler exceeds the above range, the amount of the binder for sufficiently covering the surface of the filler may be insufficient, and the sealing performance of the sheet-shaped sealing material may deteriorate. If the content of the filler is less than 5% by weight, the effect of adding the filler, that is, the stress relaxation property of the sheet-shaped sealing material and the improvement of the sealing performance cannot be expected so much.

The rubber and thermosetting resin used in the compound containing various components as described above are used in a fluid state, in a latex state, a solution state, and the like. Specifically, for example, solution rubber (solid Mixture of rubber and solvent),
It is used as liquid rubber (for example, liquid silicone rubber, liquid fluororubber, etc., liquid rubber alone without solvent), rubber latex, solution resin, resin emulsion and the like. Further, these rubbers and resins may be used alone or in combination of two or more kinds.

The method for preparing such a compound is not particularly limited, and a conventionally known method may be adopted. <Nonwoven fabric> Nonwoven fabric is a base material for a sheet-shaped sealing material and contributes to the improvement of strength.
Asbestos-based or non-asbestos-based can be used. From the viewpoint of safety to human body and environment, non-asbestos-based nonwoven fabric is preferably used. Among such non-asbestos-based nonwoven fabrics, for example, p-aramid fiber Fibers having high strength at high temperatures, such as fluororesin fibers, carbon fibers, ceramic fibers, and mineral fibers, can be preferably used alone or in combination.

There are various methods for producing such a non-woven fabric, such as wet type, dry type, spun lace, spun bond, melt blown, needle punch, stitch bond and the like. The type of non-woven fabric used in the present invention is the present process. It is not limited. The properties of the obtained non-woven fabric are preferably needle punched felt-like ones, wet papermaking non-woven fabric-like ones and the like.

In the present invention, the non-woven fabric, which contributes to the improvement of the strength of the sheet-shaped sealing material, includes the solid content in the compound,
Total 100% by weight with non-woven fabric (or fiber for non-woven fabric)
Usually, it is used in an amount of 5 to 80% by weight, preferably 10 to 70% by weight. If the content of the non-woven fabric (or fiber) is less than 5% by weight, the sheet strength that can withstand actual use cannot be obtained, while if it exceeds 80% by weight, the voids in the non-woven fabric increase as the content of the non-woven fabric increases. More,
The amount of compound to be impregnated / filled into the void becomes insufficient,
There is a tendency that a sheet-shaped sealing material having sufficient sealing performance cannot be obtained.

<Compound Preparation Step (Step 1)> In the present invention, the organic binder (a) comprising the rubber material and the thermosetting resin, the binder solvent or dispersion medium (c), and the filler used if necessary. Chemicals (and chemicals for resin if necessary) corresponding to the rubber material and thermosetting resin contained in the binder and binder (b) (eg vulcanizing agent, vulcanization aid, accelerator, anti-aging agent) Etc.) into a stirring vessel and stir / mix until uniform to prepare a compound.
At this time, if necessary, a thickener, a surfactant, a filler (e)
You may mix these. Such stirring / mixing is usually carried out at room temperature (20 to 30 ° C.) and normal pressure, and if necessary, the components may be heated to a temperature at which chemical changes do not occur.

<Step of impregnating compound and expelling gas (step 2)> Next, in the present invention, the gas existing inside the nonwoven fabric is forcibly expelled, and the compound (binder mixture liquid) obtained as described above is also used. ) Is impregnated into a non-woven fabric composed of base fibers. Here, in order for the sheet-shaped sealing material to have excellent sealing performance, it is necessary to completely replace and fill the voids present inside the nonwoven fabric with a compound.

In order to completely fill the voids with the compound as described above, in the present invention, the step of forcibly expelling the gas (usually air) present inside the nonwoven fabric and impregnating the compound with any of the following From the viewpoint of efficiency and the like, it is desirable to carry out the method described in the above, especially the method described in the above. That is :: A method of immersing a nonwoven fabric in a compressed state in advance in a compound and spontaneously restoring it in the compound (also referred to as "preliminary compression liquid spontaneous restoration method"); :: A nonwoven fabric in the compound A method of compressing and spontaneously restoring it in a compound (also called "in-liquid compression spontaneous restoration method") ;: A method of performing high pressure spraying of the compound onto a nonwoven fabric (also called "high pressure spraying method" Or): A method in which a non-woven fabric is placed in a vacuum container and the interior of the container is decompressed and then a compound is injected (also referred to as "vacuum injection method or vacuum substitution method");

This method (pre-compressed liquid spontaneous restoration method)
In, the non-woven fabric is extruded by compressing and compressing the non-woven fabric in advance to reduce the voids in which the gas exists, and the non-woven fabric with the reduced and removed voids is immersed in the compound and pressed onto the non-woven fabric in the compound. When opened, the nonwoven fabric will spontaneously restore to its original shape. At this time, the inside of the non-woven fabric is in a negative pressure state, and the compound is sucked into the non-woven fabric to infiltrate into the non-woven fabric, so that the fiber gaps forming the non-woven fabric can be completely filled with the compound.

In the above method (compression spontaneous recovery method in liquid), the non-woven fabric is immersed in the compound, and the non-woven fabric is pressurized and compressed, and the non-woven fabric is spontaneously restored by releasing the pressure. The method is similar. In the method (high-pressure spraying method), the compound sprayed on the surface of the nonwoven fabric under high pressure may be decompressed and sucked by a suction device provided on the back surface of the nonwoven fabric to improve the efficiency of spraying and impregnating the compound.

The method (reduced pressure injection method) is a method of substituting the voids inside the nonwoven fabric with a compound under reduced pressure. When the inside of the container is kept under reduced pressure, the voids inside the nonwoven fabric are also under reduced pressure. . When the compound is injected into the container under such reduced pressure, the compound diffuses into the container under the negative pressure and also penetrates into the voids in the nonwoven fabric, and as a result, the fiber gap in the nonwoven fabric is filled with the compound. You can Such a reduced-pressure injection method is effective without requiring large-scale equipment, for example, when the size of the nonwoven fabric is relatively small.

In the present invention, as the method for restoring the compressed nonwoven fabric, spontaneous restoration by pressure release is preferable as described above, but restoration may be forced. If the amount of the compound impregnated into the nonwoven fabric is not sufficient by only performing the above-mentioned methods (operations) once depending on the unfamiliarity between the nonwoven fabric and the compound or the viscosity of the compound, the method is repeated a plurality of times. Repeatedly, it is desirable to completely fill the interstices of the fibers forming the nonwoven fabric with the binder mixed liquid.

If the non-woven fabric is water repellent and repels the compound even when the non-woven fabric is impregnated with the compound, the compound is preliminarily mixed with a surfactant in the above-mentioned "compound preparation step". It is desirable to keep. Also, the viscosity of the compound is low,
A part of the compound impregnated in the non-woven fabric may flow out, and voids may be formed inside the non-woven fabric again. In such a case, it is desirable to add a thickener to the compound in the “compound preparation step” to reduce the fluidity of the compound.

In the present invention, after impregnating the non-woven fabric with the compound as described above, the obtained compound-impregnated non-woven fabric is inserted between a pair of rolls adjusted to have a predetermined interval, so that the amount of adhering compound (impregnation amount) ) Is preferably set (adjusted) to a predetermined amount. Next, with respect to such “compound impregnation and gas purging step”, an embodiment using various impregnation machines suitable for the step will be described in more detail with reference to the drawings.

<FIG. 1> In the present invention, for example, in the case of adopting the above method, a roll-conveying type impregnating machine 10 schematically shown in FIG. 1 is used to perform “nonwoven fabric compression-compound impregnation-nonwoven fabric spontaneous restoration”. It is possible to automate the impregnation step by continuously performing the respective operations of "adhesion amount setting".

The roll-conveying impregnator 10 shown in FIG.
Is the impregnation tank 3 in which the compound 2 is stored, and the impregnation tank 3
Provided outside of the impregnation tank 3, the delivery rolls 7 and 8 for feeding the nonwoven fabric 1 to the impregnation tank 3, the compression roll 4 for guiding the fed nonwoven fabric 1 into the impregnation tank 3, and compressing the same. And a pair of squeezing / driving rolls 5 and 6 for adjusting the amount of compound in the nonwoven fabric 1 that has passed through the impregnation tank 3.

In this roll-conveying type impregnation machine 10, the nonwoven fabric 1 is guided into the impregnation tank 3 by the compression roll 4 via the delivery rolls 7 and 8 and is immersed in the compound 2 in the impregnation tank 3. While being held and stretched in a tensioned state by the delivery rolls 7 and 8, the compression roll 4, and the pair of upper and lower squeezing / driving rolls 5 and 6, the compression roll 4 compresses by receiving downward pressure. .

The nonwoven fabric tension, compression surface pressure, etc. at this time are not generally determined depending on the material, manufacturing method, condition of the nonwoven fabric, etc., but the tension such that the elongation of the nonwoven fabric is 1 to 5%, or during compression 10-40% of original substrate thickness
It is desirable to apply a load such that the thickness can be adjusted. Such conditions can be achieved by appropriately adjusting the rotational speed of these rolls, the 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 nonwoven fabric 1 is excessively stretched when held in such a tensioned state, a "belt / mesh conveying type impregnating machine" 20 shown in FIG.
Can be used. The nonwoven fabric 1 thus compressed by the compression rolls 4 in the impregnation tank 3 is released from the pressure of the compression rolls 4 after passing through the compression rolls 4 and moves toward the upper and lower squeezing / driving rolls 5 and 6. In this process, the voids in the nonwoven fabric 1 become a negative pressure, and the compound 2 in the impregnated layer is sucked into the voids to spontaneously restore the nonwoven fabric 1.
The spaces between the fibers are filled with compound 2 (not shown). The nonwoven fabric 1 in which all the inter-fiber voids are filled with the compound in this way is sandwiched (inserted) by a pair of squeezing / driving rolls 5 and 6 provided outside the impregnation tank 3 to impregnate the nonwoven fabric 1.・ The amount of attached compound is usually
The amount is adjusted to be 3 to 40 times, preferably 5 to 35 times the weight of the nonwoven fabric.

Further, in the present invention, as described above, the above-mentioned non-woven fabric is usually 5% in the total 100% by weight of the solid content in the compound and the non-woven fabric (or the fiber for non-woven fabric).
It is used in an amount of -80% by weight, preferably 10-70% by weight. A plurality of such "belt / mesh conveying type impregnation machines" 20 may be installed in the vertical direction to repeat the compound impregnation treatment of the nonwoven fabric a plurality of times.

In the above example, the case where the number of the compression rolls is one is shown, but the present invention is not limited to such a mode,
For example, as shown by number 4a in FIG.
A compression roll may be provided below the non-woven fabric 1 so as to be paired with the non-woven fabric 1, and the non-woven fabric 1 may be compressed and pinched by the pair of compression rolls 4 and 4a. Further, a pair of upper and lower compression rolls are provided in the plurality of sets of impregnation tanks 3 to "compress / release-" the nonwoven fabric.
The "impregnation" may be repeated to increase the impregnation efficiency (not shown).

<FIG. 2> Further, in the present invention, when the above method (in-liquid compression spontaneous restoration method) is adopted, a belt-conveying impregnator 20 schematically shown in FIG. The above-mentioned impregnation step can be automated by continuously performing the operations of "compression-compound impregnation-nonwoven fabric spontaneous restoration-adhesion amount setting".

The belt transfer type impregnating machine 20 shown in FIG.
Is the impregnation tank 3 in which the compound 2 is stored, and the impregnation tank 3
And the upper and lower delivery rolls 25a and 26a provided outside the front of the non-woven fabric 1 for delivering the non-woven fabric 1 to the impregnation tank 3, and the non-woven fabric 1 delivered
The compression roll 4 for guiding and compressing into the impregnation tank 3 and the nonwoven fabric 1 provided outside the impregnation tank 3 and passing through the impregnation tank 3.
It is provided with a pair of upper and lower diaphragm / drive rolls 5 and 6 for adjusting the amount of compound therein.

Two conveyor belts 21 and 22, which may be in the form of an endless track mesh, are bridged over the belt conveyor impregnator 20, and the upper conveyor belt 21 includes an upper delivery roller 25a and a compression roller 4. Around the upper diaphragm / driving roll 5, a spontaneous restoration roll 25b is provided between the compression roll 4 and the upper diaphragm / driving roll 5.

The lower conveyor belt 22 is the lower delivery roll 2
6a, the compression roll 4, and the lower squeezing / driving roll 6, and auxiliary rolls 26c and 26b are provided between the lower squeezing / driving roll 6 and the lower delivery roll 26a. Belt-conveying type impregnating machine 2 having such a configuration
0, the upper conveyor belt 21 is partially attached to the surface of the compression roll 4.
The inner surface of the lower conveyor belt 22 is in circumferential contact with the outer surface of the upper conveyor belt 21 which is in circumferential contact with the compression roll 4, and the outer surface of the lower conveyor belt 22 is also in tension.

The belt conveyor impregnating machine 20 having such a structure
Then, the nonwoven fabric 1 is sandwiched and guided by the upper and lower conveyor belts 21 and 22 between the upper and lower delivery rolls 25a and 26a,
It is guided into the impregnation tank 3 in which the compression roll 4 exists, is immersed in the compound 2 in the impregnation tank 3, and is sandwiched and compressed by the upper and lower conveyor belts 21 and 22 below the compression belt 4. By appropriately adjusting the rotation speed of the compression roll 4 and the tension of the lower conveyance belt 22, the compression surface pressure, the compression amount of the nonwoven fabric 1 in the compression roll 4 part, the compression time, etc. are the same as in the above example. , Can be adjusted appropriately.

The strength of the non-woven fabric 1 used is not particularly high and the impregnating machine 10 as shown in FIG. 1 is used. Since the non-woven fabric 1 is not excessively stretched when sandwiched between 21 and 22 and conveyed, this belt conveyance is performed for a wide variety of non-woven fabrics having different base fiber types and their contents, tensile strengths and the like. A machine impregnator 20 can be used.

<FIG. 3> In the present invention, when the above method (high pressure spraying method) is adopted, a mesh-shaped base 31 is used by using the high pressure spray impregnating machine 30 schematically shown in FIG.
The above-mentioned impregnation is performed by spraying the compound 1a from above the non-woven fabric 1 placed on it to the surface of the non-woven fabric 1 below and continuously changing the relative positions of the non-woven fabric 1 and the spray nozzle 32a. It is possible to automate the process.

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

As described above, the nonwoven fabric 1 is placed on the mesh base 31, and the compound is sprayed from above to the surface of the nonwoven fabric 1 to uniformly and sufficiently penetrate the compound into the inside of the nonwoven fabric ( Can be impregnated). The conditions for efficiently impregnating the nonwoven fabric 1 with the compound by the high-pressure spray method differ 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 generally determined, but for example, The above conditions can be set so as to spray 10 to 50 times the impregnated amount.

<FIG. 4> FIG. 4 shows a mode in which the suction device 33 is provided below the mesh base 31 in the high-pressure spray impregnation machine 30 shown in FIG. As shown in FIG. 4, if a suction device 33 is provided below the mesh base 31 to decompress / suck gas or the like in the nonwoven fabric 1, the permeation (impregnation) efficiency of the compound 1 can be further enhanced.

Any of these impregnating machines 10, 20, 30,
Even in the case of using 30A, in order to uniformly impregnate the inside of the nonwoven fabric 1 with the compound 2, after impregnating the inside of the nonwoven fabric with the compound in a predetermined amount or more, as shown in FIG.
As indicated by reference numerals 5 and 6 in FIG. 2, it is desirable to insert the roll between a pair of rolls adjusted to a predetermined interval. By using the impregnating machine shown in the above embodiment, the compound can be uniformly and completely impregnated into the inside of the nonwoven fabric, and it is possible to obtain a sheet-shaped sealing material having excellent gas and liquid sealing properties. The invention is not limited to such an embodiment using an impregnating machine, and the above-mentioned “preliminary compression spontaneous recovery method in liquid”, “submerged compression spontaneous recovery method”, “high pressure spray method”, “reduced pressure injection method, reduced pressure replacement method”, etc. The present invention can be preferably used insofar as it adopts.

In the present invention, as described above, the inside of the nonwoven fabric is impregnated with the compound, and the gas such as air existing in the voids inside the nonwoven fabric is expelled forcibly and substantially completely to remove the voids in the nonwoven fabric. After replacing and filling with compound, dry the sheet in the following "drying process",
We have obtained a sheet-shaped sealing material. <Drying Step (Step 3)> In the nonwoven fabric after completion of the above-mentioned “compound impregnation and gas purging step” (also simply referred to as impregnation step), a solvent or dispersion unnecessary for the sheet-shaped sealing material which is the final product. The medium is included. When the rubber component is crosslinked or the resin component is cured in this state, the solvent or dispersion medium remains in the sheet-shaped sealing material, and the sheet-shaped sealing material cannot exhibit stable sealing performance. Therefore, for the nonwoven fabric impregnated with the compound, the solvent or the dispersion medium is removed from the nonwoven fabric after the completion of the impregnation step before the following drying step.

Removal of the solvent or dispersion medium is carried out at 80 ° C. or higher,
Desirably, by heating the sheet for about 1 to 3 hours in a dryer set to 80 ° C. or higher and 100 ° C. or lower,
The solvent or dispersion medium may be volatilized and removed. When the sheet is dried at a high temperature of more than 100 ° C., the solvent or dispersion medium in the nonwoven fabric may be rapidly vaporized and expanded to generate voids inside the nonwoven fabric. Moreover, if the drying process is carried out at a temperature above 100 ° C., the following “molding process” is performed.
Before carrying out, since the crosslinking of the rubber in the sheet and the curing of the resin are promoted, the effect of improving the airtightness by compression may not be sufficiently obtained in the following "molding step". 80 ℃ again
When the sheet is dried at a temperature below 1, it takes a long time to completely evaporate and remove the solvent or dispersion medium, which is inefficient.

<Molding Step (Step 4)> In the present invention, the dried product (sheet) obtained through the above-mentioned drying step is pressed under heating in this “molding step”, so that after the drying step is completed, The airtightness of the sheet is improved and the compounded rubber component is crosslinked or the resin component is cured. A hot press is usually used as the molding device.

The molding conditions differ depending on the composition of the components and the like and are not generally determined, but the heating temperature is usually 100 to 25.
0 ° C, heating time 3 to 15 minutes, compression surface pressure 5 to 40 MPa
It is appropriately set within the range. When vulcanization or curing by hot pressing is insufficient, secondary heating under dry heat or moist heat can more effectively accelerate the rubber vulcanization or resin curing. Such secondary heating is performed under the following conditions. That is, the heating temperature is usually 150 to 250 ° C., and the heating time is 0.5 to 24.
It may be maintained for a time, under dry heat, or under moist heat. In the case of secondary vulcanization, normally, surface pressure is not applied and free baking is often adopted.

In the sheet-shaped sealing material thus obtained, the rubber material as the organic binder and the thermosetting resin are generally 5 to 40% by weight, preferably 10 to 40% by weight.
In the amount of 30% by weight, the base fiber constituting the non-woven fabric is
Usually, the amount of the filler is 5 to 80% by weight, preferably 10 to 70% by weight, more preferably 10 to 50% by weight, and if necessary, the amount of the filler is 0 to 80% by weight. In that case, it is desirable that the amount is preferably 5 to 80% by weight, more preferably 30 to 80% by weight.

The sheet-like sealing material thus obtained has excellent stress relaxation characteristics, can maintain excellent gas sealing property and liquid sealing property at high temperature for a long period of time, and has an anisotropic strength of the sealing material. There is no nature.

[0078]

EFFECTS OF THE INVENTION According to the method for manufacturing a sheet-shaped sealing material according to the present invention, the following effects can be obtained. In the present invention, since the thermosetting resin having a better heat resistance than the rubber material is used in combination with the rubber material in a specific amount ratio in this manner, the stress relaxation property and long A sheet-shaped sealing material having a stable period and improved sealing performance can be obtained.

[0079]

Example 1 NBR latex in solid content of 22.
2 kg, phenol resin emulsion in solid content 1.8 kg, phlogopite 48 kg, powdered sulfur 0.6 kg,
Powdered zinc white 0.6 kg, polycarboxylic acid salt dispersant in solid content weight 0.2 kg, polyethylene glycol antifoaming agent in solid content weight 0.2 kg, polyvinyl alcohol thickener in solid content weight 0.4 kg is mixed with water 46
A compound (total solids weight 74 kg) was prepared by diluting with L.

Next, a needle punch felt (weight per unit area: 500 g / m ² , weight: 4) produced by using pitch-based carbon fiber.
(kg) in the above compound to obtain the original thickness of about 3
The felt was impregnated with the compound by compressing it to 0% and spontaneously restoring it. The felt sheet to which an excessive amount of compound was adhered was passed between biaxial rolls adjusted at 4 mm intervals so that the amount of compound adhered was adjusted to 6.5 times (26 kg) the weight of the needle punch felt.

This was placed in an electric furnace and heated at 50 ° C. for 30 minutes.
Min, and dried by heating at 90 ° C. for 90 minutes. 170 ℃
It was compressed for 10 minutes at a surface pressure of 16 MPa with the press vulcanizer set to. The stress relaxation rate (according to JIS R3453, 200 ° C., 22 hours) of the obtained sheet-shaped sealing material was 45%, and the room temperature sealability (according to ASTM F37-B. Surface pressure 19.8 MPa, nitrogen internal pressure 0.98 MPa). )
Was 3 × 10 ⁻⁴ Pa · m ³ / s.

Tables 1 and 2 show the blending amount of each component and the test results.

[0083]

Example 2 NBR latex was added in an amount of 20.
3 kg, phenol resin emulsion 3.7 kg by solid weight, phlogopite 48 kg, powder sulfur 0.6 kg,
Powdered zinc white 0.6 kg, polycarboxylic acid salt dispersant in solid content weight 0.2 kg, polyethylene glycol antifoaming agent in solid content weight 0.2 kg, polyvinyl alcohol thickener in solid content weight 0.4 kg is mixed with water 46
A compound (total solids weight 74 kg) was prepared by diluting with L.

Then, in the same manner as in Example 1 except that the above compound was used, the same needle punch felt (weight per unit area: 500 g / m ² , weight: 4 kg) produced by using pitch-based carbon fibers was impregnated with the compound, and 2 Pass it through the shaft rolls and adjust it so that the amount of compound attached is 6.5 times (26 kg) the weight of the needle punch felt.
It was dried and molded.

The stress relaxation rate (according to JIS R3453, 200 ° C., 22 hours) of the obtained sheet-shaped sealing material was 46%, and the room temperature sealability (according to ASTM F37-B. Surface pressure 19.8 MPa, nitrogen internal pressure). 0.98 MPa)
Was 2 × 10 ⁻⁴ Pa · m ³ / s. The blending amount of each component and the test results are also shown in Tables 1 and 2.

[0086]

[Example 3] 18. NBR latex in solid content weight of 18.
5 kg, phenol resin emulsion solid weight 5.5 kg, phlogopite 48 kg, powdered sulfur 0.6 kg,
Powdered zinc white 0.6 kg, polycarboxylic acid salt dispersant in solid content weight 0.2 kg, polyethylene glycol antifoaming agent in solid content weight 0.2 kg, polyvinyl alcohol thickener in solid content weight 0.4 kg is mixed with water 46
A compound (total solids weight 74 kg) was prepared by diluting with L.

Then, the same needle punch felt (weight per unit area: 500 g / m ² , the same as in Example 1 except that the above compound was used, produced by using pitch-based carbon fibers.
(Weight: 4 kg) was impregnated with the compound, passed through a biaxial roll, adjusted so that the amount of the compound adhered was 6.5 times (26 kg) the weight of the needle punch felt, and dried and molded.

The stress relaxation rate (according to JIS R3453, 200 ° C., 22 hours) of the obtained sheet-shaped sealing material was 40%, and the room temperature sealability (according to ASTM F37-B. Surface pressure 19.8 MPa, nitrogen internal pressure). 0.98 MPa)
Was 1 × 10 ⁻⁴ Pa · m ³ / s. The blending amount of each component and the test results are also shown in Tables 1 and 2.

[0089]

Example 4 Needle manufactured using pitch-based carbon fiber
Punch felt (Basis weight 325 g / m ² 2.6 kg)
The compound prepared in Example 3 was included in the same manner as in Example 1.
Soaked and compounded amount of needle punch felt
The weight was adjusted to be 11 times (28.6 kg).

Then, a drying step and a molding step were carried out in the same manner as in Example 1 except that the above compound was used. Stress relaxation rate of the obtained sheet-shaped sealing material (JIS
R3453 compliant, 200 ° C., 22 hours) is 47%, and room temperature sealability (ASTM F37-B compliant. Surface pressure 19.8 MPa, nitrogen internal pressure 0.98 MPa) is 1 × 10.
^-4 Pa · m ³ / s.

The compounding amounts of each component and the test results are also shown in Tables 3 to 6.

[0092]

Example 5 Needle manufactured using pitch-based carbon fiber
Punch felt (Basis weight 125g / m ²  1 kg))
The compound prepared in Example 3 (total solids weight 74 k
g) was impregnated in the same manner as in Example 1, and the amount of compound adhered
Is 31 times the needle punch felt weight (31 kg)
I adjusted it so that.

Then, in the same manner as in Example 1, a drying process and a molding process were performed. Stress relaxation rate of the obtained sheet-shaped sealing material (according to JIS R3453, 200 ° C., 2
50% for 2 hours, and room temperature sealability (ASTM F
Compliant with 37-B. Surface pressure 19.8 MPa, nitrogen internal pressure 0.9
8 MPa) was 1 × 10 ⁻⁴ Pa · m ³ / s.

The compounding amounts of each component and the test results are also shown in Tables 5-6.

[0095]

[Comparative Example 1] NBR latex with a solid content of 24 k
g, phlogopite 48 kg, powdery sulfur 0.6 kg, powdery zinc white 0.6 kg, polycarboxylic acid salt dispersant 0.2 kg by solid content, polyethylene glycol antifoaming agent by solid content 0. By mixing 2 kg and 0.4 kg of polyvinyl alcohol-based thickener in solid content weight and diluting with 46 L of water, a compound (total solid content weight of 74 k
g) was produced.

[0096] Then, similarly except using the compound from Example 1, needle punched felt of the same manufactured using pitch-based carbon fibers (basis weight 500 g / m ^2,
(Weight: 4 kg) was impregnated with the compound, passed through a biaxial roll, adjusted so that the amount of the compound adhered was 6.5 times (26 kg) the weight of the needle punch felt, and dried and molded.

The stress relaxation rate (according to JIS R3453, 200 ° C., 22 hours) of the obtained sheet-shaped sealing material was 69%, and the room temperature sealing property (according to ASTM F37-B. Surface pressure 19.8 MPa, nitrogen internal pressure). 0.98 MPa)
Was 1 × 10 ⁻⁴ Pa · m ³ / s. The blending amount of each component and the test results are also shown in Tables 1 and 2.

[0098]

[Comparative Example 2] NBR latex in solid content of 16.
6 kg, phenol resin emulsion in solid weight of 7.4 kg, phlogopite 48 kg, powdered sulfur 0.6 kg,
Powdered zinc white 0.6 kg, polycarboxylic acid salt dispersant in solid content weight 0.2 kg, polyethylene glycol antifoaming agent in solid content weight 0.2 kg, polyvinyl alcohol thickener in solid content weight 0.4 kg is mixed with water 46
A compound (total solids weight 74 kg) was prepared by diluting with L.

Then, a needle punch felt (weight per unit area: 500 g / m ² , weight: 4 kg) produced by using pitch-based carbon fibers was impregnated with the compound in the same manner as in Example 1 except that the above compound was used. Through the gap, the amount of the attached compound was adjusted to 6.5 times (26 kg) the weight of the needle punched felt, and dried and molded.

The stress relaxation rate (according to JIS R3453, 200 ° C., 22 hours) of the obtained sheet-like sealing material was 67%, and the room temperature sealing property (according to ASTM F37-B. Surface pressure 19.8 MPa, nitrogen internal pressure). 0.98 MPa)
Was 1 × 10 ⁻⁴ Pa · m ³ / s. The blending amount of each component and the test results are also shown in Tables 1 and 2.

[0101]

Comparative Example 3 A joint sheet forming composition having the following composition was prepared. Asbestos fibers 75.3% by weight SBR 12.5% by weight Rubber chemicals 3.2% by weight Inorganic filler (clay) 9.0% by weight Toluene 0.7% relative to 1 kg of the above mixture The composition obtained was obtained. The composition thus obtained was inserted between a hot roll kept at 130 ° C. and a chill roll kept at 30 ° C., and hot rolled. In this way, the composition was layered in a sheet form on the hot roll side. This sheet is peeled off from the heat roll with a doctor blade and has a thickness of 1.5 mm.
I got a joint sheet of.

The stress relaxation rate (according to JIS R3453, 200 ° C., 22 hours) of the obtained sheet-like sealing material was 40%, and the room temperature sealing property (according to ASTM F37-B. Surface pressure 19.8 MPa, nitrogen internal pressure). 0.98 MPa)
Was 2 × 10 ⁻³ Pa · m ³ / s. The blending amount of each component and the test results are also shown in Tables 1 and 2.

[0103]

[Comparative Example 4] Needles manufactured using pitch-based carbon fibers
Punch felt (Basis weight 325 g / m ² , Weight: 2.6k
g) compound prepared in Comparative Example 1 (total solid content weight)
74 kg) and impregnated as in Example 1 with compound
11 times the needle punch felt weight (28.6
  kg).

Then, in the same manner as in Example 1, a drying step and a molding step were performed. Stress relaxation rate of the obtained sheet-shaped sealing material (according to JIS R3453, 200 ° C., 2
67% in 2 hours, room temperature sealability (ASTM F
Compliant with 37-B. Surface pressure 19.8 MPa, nitrogen internal pressure 0.9
8 MPa) was 1 × 10 ⁻⁴ Pa · m ³ / s.

The compounding amounts of each component and the test results are also shown in Tables 3-4.

[0106]

[Comparative Example 5] Needles manufactured using pitch-based carbon fibers
Punch felt (Basis weight 325 g / m ², Weight: 2.6k
g) the compound prepared in Comparative Example 2 (total solid content weight)
74 kg) and impregnated as in Example 1 with compound
11 times the needle punch felt weight (28.
6 kg).

Then, in the same manner as in Example 1, a drying process and a molding process were performed. Stress relaxation rate of the obtained sheet-shaped sealing material (according to JIS R3453, 200 ° C., 2
64% for 2 hours, and room temperature sealability (ASTM F
Compliant with 37-B. Surface pressure 19.8 MPa, nitrogen internal pressure 0.9
8 MPa) was 1 × 10 ⁻⁴ Pa · m ³ / s.

The blending amounts of each component and the test results are also shown in Tables 3-4.

[0109]

Comparative Example 6 Needle manufactured using pitch-based carbon fiber
Punch felt (Basis weight 125g / m ², Weight: 1 kg)
To the compound prepared in Comparative Example 1 (total solids weight 74
kg) and impregnated in the same manner as in Example 1, and the amount of compound attached
Is 31 times the needle punch felt weight (31 kg)
I adjusted it so that.

Then, in the same manner as in Example 1, a drying process and a molding process were performed. Stress relaxation rate of the obtained sheet-shaped sealing material (according to JIS R3453, 200 ° C., 2
71% for 2 hours, room temperature sealability (ASTM F
Compliant with 37-B. Surface pressure 19.8 MPa, nitrogen internal pressure 0.9
8 MPa) was 1 × 10 ⁻⁴ Pa · m ³ / s.

The blending amount of each component and the test results are also shown in Tables 5-6.

[0112]

[Comparative Example 7] Needles manufactured using pitch-based carbon fibers
Punch felt (Basis weight 125g / m ², Weight: 74k
g)) the compound prepared in Comparative Example 2 (total solids weight)
1 kg) was impregnated in the same manner as in Example 1, and with compound
31 times the needle punch felt weight (31k
g) was adjusted.

Then, in the same manner as in Example 1, a drying process and a molding process were performed. Stress relaxation rate of the obtained sheet-shaped sealing material (according to JIS R3453, 200 ° C., 2
71% for 2 hours, room temperature sealability (ASTM F
Compliant with 37-B. Surface pressure 19.8 MPa, nitrogen internal pressure 0.9
8 MPa) was 1 × 10 ⁻⁴ Pa · m ³ / s.

The blending amount of each component and the test results are also shown in Tables 5-6. <Discussion> From the table, it can be seen that the blending amount of the thermosetting resin for the organic binder (a) has the optimum value range as described above. As shown in the table, as the organic binder (a),
Although the stress relaxation property was improved by adding the thermosetting resin component together with the rubber material, when the thermosetting resin component exceeded 30% by weight in the organic binder, it was deteriorated.

Organic binder in an amount specified in the present invention
(a) The use of a thermosetting resin is believed to be because the stress relaxation property is improved and the resin component in the sheet-shaped sealing material exerts heat resistance, which is effective in suppressing the deterioration of the rubber component. It When the amount of the thermosetting resin in the organic binder (a) exceeds the range specified in the present invention, the stress relaxation property is deteriorated, which is a rubber component which is an elastic component in the organic binder (a). It is conceivable that this is because the sheet has a relatively small amount of restoring force, which makes it difficult to restore the sheet because the sheet has little restoring force.

The resin component is less elastic than the rubber component, and a resin skeleton is formed in the sheet by blending a large amount of the resin component, and plastic deformation occurs due to the stress at the time of tightening the sheet-shaped sealing material to cause the sheet-shaped seal. It is considered that there is a tendency to suppress (restraint) the restoring force of the material. In addition Example 3, normal sealability 1 × 10- ⁴ Pa ·
indicates m ³ / s, greater than normal sealability ^{2 × 10 -3 Pa · m 3} / s with the asbestos joint sheet, by stress relaxation rate are both 40%, the sheet-like seal comparable to asbestos joint sheet It can be seen that it is a material (sheet gasket).

[0117]

[Verification test] A verification test was conducted by confirming whether or not each of the above-mentioned sheet gaskets (sheet-shaped sealing material) can maintain its sealing performance under high temperature conditions. That is, JI
A test piece manufactured in the shape of a gasket using each of the above-mentioned sheet-shaped sealing materials was fastened to a steel pipe flange of 10 k, 25 A specified in SB2210 at a surface pressure of 19.8 MPa, and heat-treated at 300 ° C for 1 month. went.

After leaving to cool, a sealing test (according to ASTM F37-B) was carried out at an internal pressure of nitrogen of 0.98 MPa, and if the leakage amount was more than 1 × 10 ⁻³ Pa · m ³ / sec, it was judged as a defective seal. Those below were judged to be good in sealing. As a result, Examples 1 to 5 and Comparative Example 3 had good sealing, and Comparative Examples 1, 2, 4, and 5 had poor sealing.

From this, it was confirmed that the superiority or inferiority of the stress relaxation characteristics is effective for evaluating the long-term sealing property. <Discussion> From the above Examples, Comparative Examples and verification tests, it is understood that the sheet-like sealing material exhibiting high airtight sealing property and good stress relaxation characteristics can be produced by the production method of the present invention.

In the present invention, the organic binder (a) is composed of a rubber material and a thermosetting resin, and the thermosetting resin is contained in the specific amount as described above. The sheet-shaped sealing material of the present invention using a compound containing), etc. can be manufactured without impairing the workability and sealing characteristics as compared with the conventional products, and the stress relaxation characteristics are significantly improved.

[0121]

[Table 1]

[0122]

[Table 2]

[0123]

[Table 3]

[0124]

[Table 4]

[0125]

[Table 5]

[0126]

[Table 6]

[Brief description of drawings]

FIG. 1 is a schematic diagram of a roll-conveying impregnator that is preferably used in one embodiment of the present invention and is capable of continuously performing the operations of non-woven fabric compression-compound impregnation-non-woven fabric spontaneous restoration-adhesion amount setting. FIG.

FIG. 2 is a belt-conveying type which is preferably used in one embodiment of the present invention and which is capable of continuously performing the operations of non-woven fabric compression in a compound, compound impregnation, non-woven fabric spontaneous restoration, and adhesion amount setting. It is a model explanatory view of an impregnation machine.

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

4 is a schematic view of the high pressure spray impregnation machine 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 ... Nonwoven fabric 1a, 2 ... Compound (binder mixture) 3 ... Impregnation tank 4 ... (upper) compression roll 4a ... (upper) compression Compressing rolls 5 and 6 paired with the rolls (lower part), squeezing / driving rolls 7, 8, delivery rolls 10, roll-conveying impregnator 20, belts・ Mesh-conveying type impregnating machines 21, 22 ... Conveying belts 25a, 26a ... Vertical sending rolls 25b ... Spontaneous restoration rolls 26b, 26c. ... High-pressure spray impregnation machine 30A ... High-pressure spray impregnation machine 31 ... Mesh base 32a ... Spray nozzle 33 ... Suction device

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16J 15/10 F16J 15/10 X (72) Inventor Shinya Kurokawa Industrial park 5 in Sumagawa-cho, Gojo city, Nara -2 F-Term in Research & Development Division, Nippon Bulker Industry Co., Ltd. (reference) 3J040 BA01 EA15 FA05 FA18 FA19 HA01 4F072 AB02 AB06 AB08 AB10 AB29 AD02 AD07 AD08 AD09 AD13 AD20 AD21 AD24 AD45 AD47 AE00 AE01 AE02 AE06 AE10 AE12 AF25 AF26 AF29 AG06 AG12 AH02 AH03 AH13 AH31 AH32.

Claims (6)

[Claims] 1. An organic binder (a) comprising a rubber material and a thermosetting resin, the thermosetting resin being contained in an amount of 5 to 30% by weight, a chemical agent for rubber (b), and the rubber material. Solvent, resin solvent or dispersion medium (c) is mixed, and the resulting compound is used as a non-woven fabric (d) composed of base fibers.
The gas present in the nonwoven fabric is expelled and impregnated therewith, and at least a part of the solvent or dispersion medium is volatilized and removed from the nonwoven fabric impregnated with the compound, and then the nonwoven fabric is heated and compressed to add the rubber material. A method for producing a sheet-shaped sealing material, which comprises obtaining a sheet-shaped sealing material by performing vulcanization and curing of the thermosetting resin. 2. The method for producing a sheet-like sealing material according to claim 1, wherein the rubber component forming the compound is used in the form of latex and the resin component is used in the form of emulsion. 3. The method for producing a sheet-shaped sealing material according to claim 1, wherein the rubber component forming the compound is used in the form of latex and the resin component is used in the form of aqueous solution. 4. The method for producing a sheet-shaped sealing material according to claim 1, wherein the compound contains a filler (e). 5. The organic binder (a) is contained in an amount of 5 to 40% by weight in the total 100% by weight of the solid content (nonvolatile components) in the compound and the nonwoven fabric (d). The method for producing a sheet-shaped sealing material according to any one of claims 1 to 4, characterized in that: 6. A sheet-shaped sealing material obtained by the method according to claim 1.