JPH044356B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a joint sheet used as a base material for gaskets used in a wide range of industrial fields such as the chemical industry, automobiles, ships, and various types of equipment. Technical background of the invention and its problems Conventionally, asbestos joint sheets have been widely used as joint sheets. This asbestos joint sheet is made by using asbestos as a base fiber, kneading it with rubber as a binder, rubber chemicals, and filler to prepare a composition for forming a joint sheet, and then rolling this composition with a hot roll. Manufactured by inserting the joint sheet between a pair of rolls consisting of a cooling roll and hot rolling, laminating the composition for forming a joint sheet on the hot roll side, and then peeling off the sheet-like material laminated on the hot roll. It has been. Such asbestos joint sheets contain asbestos as the base fiber at a ratio of 60 to 80% by weight, but in recent years, asbestos resources have been depleted and the resulting difficulty in obtaining asbestos has arisen. The negative effects of asbestos on the human body have also been pointed out, and the use of asbestos is beginning to be reconsidered. For this reason, research is actively being conducted to produce joint sheets using fiber base materials instead of asbestos. For example, attempts have been made to manufacture joint sheets by using inorganic fibers such as glass fibers, carbon fibers, and ceramic fibers, or organic fibers such as aromatic polyamide fibers and polyethylene fibers as alternative fibers to asbestos. There is. However, the sealing properties of joint sheets obtained using asbestos substitute fibers as described above are not completely satisfactory, and there is a need to further improve the sealing properties. The present inventor has conducted extensive research in order to improve the sealing properties of joint sheets obtained using inorganic fibers such as glass fibers and ceramic fibers, organic fibers such as aromatic polyamide fibers, or both as substitute fibers for asbestos. However, quite unexpectedly, the present inventors discovered that adding a higher fatty acid ester to the joint sheet improves the sealing properties of the resulting joint sheet, leading to the completion of the present invention. Purpose of the Invention As described above, the present invention aims to improve the sealing properties of a joint sheet obtained by using inorganic fibers and/or organic fibers as base fibers without using asbestos. Summary of the invention The method for manufacturing a joint sheet according to the present invention includes:
Kneading base fibers made of inorganic fibers or organic fibers other than asbestos, or both, a rubber material, a rubber chemical, a filler, and a higher fatty acid ester,
The obtained composition for forming a joint sheet is inserted between a pair of rolls consisting of a hot roll and a cooling roll, heated and rolled, a sheet-like material is laminated on the hot roll side, and this sheet-like material is rolled from the hot roll. It is characterized by peeling. Detailed Description of the Invention The joint sheet produced by the present invention is
It consists of base fibers made of inorganic fibers and/or organic fibers other than asbestos, rubber materials, rubber chemicals, fillers, and higher fatty acid esters.
Each component will be explained in detail below. Inorganic fibers other than asbestos include glass fiber, ceramic fiber, rock wool, mineral wool, fused silica fiber, chemically treated high silica fiber, fused alumina silicate fiber, alumina continuous fiber, stabilized zirconia fiber, boron nitride fiber, and titanium. acid-alkali fiber, whisker,
Known inorganic fibers such as boron fibers, carbon fibers, and metal fibers are widely used as base fibers for forming joint sheets. Note that as the inorganic fiber according to the present invention, a small amount of asbestos fiber can be included. Examples of organic fibers include aromatic polyamide fibers, polyamide fibers, polyolefin fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyurea fibers, polyurethane fibers, and polyfluorocarbon fibers. Conventionally known organic fibers such as fibers, phenolic fibers, and cellulose fibers are widely used as base fibers for forming joint sheets. Among these, aromatic polyamide fibers (trade name Kevlar, manufactured by DuPont) and fibrillated aromatic polyamide fibers (trade name Kevlar Pulp) are particularly preferred. Such base fibers are used in joint sheets.
Preferably, it is used in an amount of 10 to 80% by weight. Rubber materials play a role in binding the above fibers, and include nitrile rubber (NBR), styrene butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR),
Butyl rubber (IIR), ethylene-propylene rubber (EPM), fluorine rubber (FPM), silicone rubber (Si), chlorosulfonated polyethylene (CSM), ethylene vinyl acetate rubber (EVA), chlorinated polyethylene (CPE), chlorinated butyl rubber Conventionally known rubbers for forming joint sheets, such as (CIR), epichlorohydrin rubber (ECO), nitrile isoprene rubber (NIR), and natural rubber (NR), are widely used. Furthermore, oil-extended rubber obtained by blending naphthenic process oil with these rubber materials, such as SBR, can also be used as the rubber material. Furthermore, such oil-extended rubber and the above-mentioned rubber materials can be used in combination. This rubber material is preferably used in an amount of 10 to 40% by weight in the joint sheet. Rubber chemicals and fillers include (i) vulcanizing agents such as sulfur, zinc oxide, magnesium oxide, peroxide, dinitrolibenzene, (ii) thiazole compounds,
Vulcanization accelerators such as polyamine compounds, sulfenamide compounds, dithiocarbamate compounds, aldehyde amine compounds, guanidine compounds, thiourea compounds, xanthate compounds, (iii) clay, talc, barium sulfate, sodium heavy carbon , graphite, lead sulfate, tripolite,
Fillers such as wollastonite are widely used. These rubber chemicals and fillers are conventionally known for forming joint sheets. The rubber chemicals and fillers are preferably used in a total amount of 20 to 80% by weight in the joint sheet. The higher fatty acid ester is preferably one that melts when a composition for forming a joint sheet containing this ester is heated and rolled into a sheet using a heating roll and a cooling roll, and therefore its melting point is lower than that of the heating roll. below the upper limit of the temperature of 160°C, preferably below 120°C, more preferably between 50 and 80°C.
It is desirable that the temperature is ℃. As such higher fatty acid esters, esters of higher fatty acids and lower alcohols, esters of higher fatty acids and polyhydric alcohols, esters of higher fatty acids and polyglycols, etc. are used alone or as a mixture.
Specifically, Splendor R300 (manufactured by Kao Soap Co., Ltd.), which is an ester of higher fatty acid and polyhydric alcohol and has a melting point of 51 to 54°C, and Splendor, which is a higher fatty acid ester with a melting point of 63±3°C.
R100 (manufactured by Kao Soap Co., Ltd.), Splendor R200, a higher fatty acid ester with a melting point of 53±3℃
(manufactured by Kao Soap Co., Ltd.), Sunend HP (Sanshin Chemical Co., Ltd.), a higher fatty acid ester with a melting point of 79°C or higher
(manufactured by Sanshin Kagaku Co., Ltd.), and Sun-Aid LP (manufactured by Sanshin Kagaku Co., Ltd.), which is a higher fatty acid ester having a melting point of 60°C or higher, are used alone or in mixtures. Such higher fatty acid ester is preferably used in the joint sheet in an amount of 0.1 to 30% by weight, preferably 0.5 to 10% by weight. This higher fatty acid ester is not blended in advance into the rubber material, but is actively blended separately into the joint sheet forming composition. If the amount of the higher fatty acid ester is less than 0.1% by weight, it is not preferable because the sealing properties of the resulting joint sheet cannot be sufficiently improved.On the other hand, if the amount exceeds 30% by weight, the sheet properties are This is not preferable because the improvement effect will not be enhanced and the physical properties of the joint sheet may deteriorate. It is presumed that the sealing properties are improved by adding higher fatty acid ester to the joint sheet for the following reasons. (a) When higher fatty acid ester is added to the composition for forming joint sheets, the viscosity during processing is reduced and generation of frictional heat is suppressed, and scorch and thermal deterioration of the rubber used as a binder are prevented. . (b) Wetting of the interface between the base fiber, filler, rubber material, and rubber chemicals is improved, resulting in better dispersion, resulting in a uniform sheet fabric and improved airtightness. Of these, (b) is the main reason. In addition, by adding higher fatty acid ester to the joint sheet, the viscosity during processing is reduced, so the kneading time of the composition for forming the joint sheet can be shortened, reducing machine torque and power consumption. The incidental effect of achieving this is also obtained. Next, a method for manufacturing a joint sheet according to the present invention will be specifically explained. A rubber material is dissolved in a solvent for rubber materials such as toluene or rubber solvent, and a rubber chemical and a filler are mixed therein, as well as a higher fatty acid ester. A base fiber consisting of inorganic fibers other than asbestos, organic fibers, or both of them is added to the obtained solution or dispersion and kneaded uniformly to prepare a clay-like composition for forming a joint sheet. The order of mixing the above components is not particularly limited. Next, this composition is inserted between a pair of rolls consisting of a hot roll and a cooling roll and heated and rolled. At this time, the temperature of the heating roll is 120~160℃, and the temperature of the cooling roll is 50℃.
Preferably, the temperature is maintained at or below 0.degree. C., and equipment containing such a pair of rolls is known as a sheeter equipment. When the composition for forming a joint sheet is inserted between a pair of rolls as described above, the composition is hot rolled and laminated into a sheet on the hot roll side. When this sheet-like composition is peeled off from the hot roll, a joint sheet is obtained. The rubber solvent is almost completely evaporated during the kneading process and hot rolling process of the joint sheet forming composition. At this time, the joint sheet forming composition to which the higher fatty acid ester is added does not adhere to the cooling roll during molding, and therefore has excellent workability, and there is no need to waste the composition. You can also get the effect of not having one. Prevention of adhesion of the joint sheet forming composition to the cooling roll can be enhanced by adding an organic antistatic agent to the composition in an amount of 0.1 to 10% by weight. Examples of organic antistatic agents include cationic antistatic agents such as lauryltrimethylammonium chloride, anionic antistatic agents such as alkyl sulfates, nonionic antistatic agents such as polyoxyethylene alkyl ether, and amphoteric antistatic agents such as betaine. A water-soluble polymer antistatic agent, a silicon compound antistatic agent, or the like is used. Effects of the Invention The joint sheet obtained by the production method according to the present invention contains higher fatty acid esters in addition to ordinary joint sheet components, and therefore has the advantage of improving the sealing properties of the joint sheet obtained. You can get the same effect. Further, the kneading time can be shortened during sheet formation, and reductions in mechanical torque and power consumption can be achieved. Furthermore, it is also possible to prevent the joint sheet forming composition from adhering to the cooling roll during sheet formation. EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples. Example 1 A composition for forming a joint sheet having the following composition was prepared. Glass fiber...6% by weight Fibrillated aromatic polyamide fiber (Kevlar pulp)...9% by weight SBR...13% by weight Rubber chemicals (vulcanizing agents)...3% by weight Filler...67% by weight High grade Fatty acid ester (Splendor R100, melting point 63±3℃...2% by weight Toluene...Ratio of 0.5 to 1Kg of the above mixture The resulting composition was heated to a temperature of 130℃ and kept at 30℃. The composition was inserted between the hot roll and the hot roll and hot-rolled. In this way, the composition was laminated in the form of a sheet on the hot roll side. This sheet-like material was peeled off from the hot roll with a doctor blade and then rolled into a joint. A sheet was obtained. At this time, no adhesion of the joint sheet forming composition to the cooling roll was observed. Next, the sealing properties of the obtained joint sheet were measured as follows. After forming a gasket from the joint sheet and inserting this gasket between the flange faces and tightening it to 300Kg/cm ² and 400Kg/cm ² ,
Nitrogen at 15 kg/cm ² was pressurized into the inside and left for 1 minute. Thereafter, soapy water was applied to the outer surface of the gasket, and after being left for 2 minutes, the foaming state, that is, the degree of leakage was observed, and the sealing characteristics of the gasket were evaluated by ranking them as shown in Table 1 below.

[Table] The results are shown in Table 2. Example 2 A joint sheet forming composition having the following composition was prepared. Glass fiber...6% by weight fibrillated aromatic polyamide fiber
...9% by weight NBR ...13% by weight Rubber chemicals (vulcanizing agents) ...3% by weight Filler ...67% by weight Higher fatty acid ester (Splendor R200, melting point 53±3℃) ...2% by weight Toluene ...at a ratio of 0.5 to the above mixture A gasket was produced from the obtained composition in the same manner as in Example 1, and then the sealing properties of the gasket were evaluated in the same manner as in Example 1. The results are shown in Table 2. Example 3 A joint sheet forming composition having the following composition was prepared. Fibrillated aromatic polyamide fiber
...20% by weight SBR ...13% by weight Rubber chemicals (vulcanizing agents) ...3% by weight Filler ...62% by weight Higher fatty acid ester (Splendor R100, melting point 63±3℃) ...2% by weight Toluene ...Ratio of 0.7 per 1 kg of the above mixture After producing a gasket from the obtained composition in the same manner as in Example 1, the sealing properties of the gasket were evaluated in the same manner as in Example 1. The results are shown in Table 2. Example 4 A joint sheet forming composition having the following composition was prepared. Fabrylated aromatic polyamide fiber
...20% by weight NBR ...13% by weight Rubber chemicals (vulcanizing agents) ...3% by weight Filler ...60% by weight Antistatic agent ...2% by weight Higher fatty acid ester (Splendor R200, melting point 53±3 °C)...2% by weight Toluene...Ratio of 0.7 per 1 kg of the above mixture After producing a gasket from the obtained composition in the same manner as in Example 1, the sealing properties of the gasket were tested in the same manner as in Example 1. evaluated. The results are shown in Table 2. Comparative Example 1 A joint sheet forming composition having the following composition was prepared. Glass fiber...6% by weight fibrillated aromatic polyamide fiber
...9% by weight SBR ...13% by weight Rubber chemicals (vulcanizing agents) ...3% by weight Filler ...69% by weight Toluene ...0.5 ratio per 1 kg of the above mixture Conducted from the obtained composition After producing a gasket in the same manner as in Example 1, the sealing properties of the gasket were evaluated in the same manner as in Example 1. The results are shown in Table 2. Comparative Example 2 A joint sheet forming composition having the following composition was prepared. Fibrillated aromatic polyamide fiber
...20% by weight NBR ...13% by weight Rubber chemicals (vulcanizing agents) ...3% by weight Filler ...64% by weight Toluene ...at a ratio of 0.7 per 1 kg of the above mixture Conducted from the obtained composition After producing a gasket in the same manner as in Example 1, the sealing properties of the gasket were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Table 2 shows that by adding a higher fatty acid ester to the composition for forming a joint sheet, the sealing properties of the joint sheet obtained are dramatically improved.

Claims (1)

[Claims] 1. A base fiber made of inorganic fibers other than asbestos, organic fibers, or both, a rubber material, a rubber chemical, a filler, and a higher fatty acid ester having a melting point of 120°C or less, The resulting composition for forming a joint sheet is inserted between a pair of rolls consisting of a hot roll and a cooling roll, heated and rolled, and the sheet material is laminated on the hot roll side. A method for manufacturing a joint sheet, which is characterized by peeling this sheet-like material from a heated roll: Base fiber: 10 to 80% by weight Rubber material: 10 to 40% by weight Rubber chemicals and filler: 20 to 80% by weight % Higher fatty acid ester: 0.5-10% by weight.