JPS62127380A - Joint sheet - Google Patents

Abstract

PURPOSE:To obtain a joint sheet which has excellent tensile strength, processability, and workability and is made without asbestos, by mixing organic fibers, sepiolite, a rubber material, and rubber chemicals. CONSTITUTION:5-50wt% organic fibers (A) [e.g., (fibrillated) aromatic polyamide fibers] is mixed with 5-75wt% fibrous sepiolite (B) of a length of 5-3,000mum, preferably 20-100mum, which is used as base fiber together with component A; 10-40wt% rubber material (C) (e.g., nitrile rubber); 0.5-20wt% rubber chemicals (D) which comprise a vulcanizing agent, such as S, ZnO or MgO, and a vulcanization accelerator, such as a thiazole compound, a polyamide compound or a sulfenamide compound; and if necessary, 0-80wt% inorganic fibers (e.g., glass fibers) and filler (e.g., clay), and 0.1-10wt% antistatic agent. This mixture is dissolved in a solvent for rubber material (e.g., toluene) and is put between a hot roll at 120-160 deg.C and a cold roll at 50 deg.C or lower to be heated and rolled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 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 equipment devices. .

Technical background of the invention and its problems Conventionally, asbestos joint sheets have been widely used as joint sheets. This asbestos joint sheet uses asbestos as the base fiber, and rubber as a binder.
A composition for forming a joint sheet is prepared by kneading a rubber chemical and a filler, and this composition is inserted between a pair of rolls consisting of a hot roll and a cooling roll and heated and rolled to form a joint sheet. The composition is laminated on the hot roll side,
It has been manufactured by then peeling off the sheet-like material laminated on a hot roll.

Such asbestos joint sheets contain asbestos as the base fiber at a ratio of 60 to 80%, but in recent years, asbestos resources have been depleted and the resulting difficulty in obtaining them has arisen, and asbestos The negative effects of 5 cotton on the human body have also been pointed out, and the use of 5 cotton has begun to be considered. For this reason, research is being actively conducted on how to manufacture joint sheets using fiber base materials instead of asbestos. For example, an attempt was made to manufacture a joint sheet by using 1t of glass fiber, carbon fiber, inorganic fiber such as ceramic fiber, or organic 4Ht such as aromatic polyamide fiber or polyethylene fiber as the asbestos fiber. is being done.

By the way, if inorganic fibers such as glass fibers and ceramic I&iM are used alone or in combination as base fibers, the base fibers will be crushed during kneading of the base fibers and rubber as a binder. The spectral ratio decreases (
There is a problem in that the tensile strength of the joint sheet is reduced.

On the other hand, when trying to use 'FJla fibers such as aromatic polyamide m fibers or fibrillated aromatic polyamide fibers as the base fiber, it is especially recommended to use fibrillated aromatic polyamide fibers as the base material H/I<M. In case of spelling, I1t! Uniformly disperse the fibers in the rubber paste as a binder and mix 8'1! There was a problem in that the sealing properties of the IQ joined sheet were not fully satisfactory.

Furthermore, even if a combination of inorganic fibers such as glass fibers and organic fibers such as Kaorokubo 1 Famido fibers is used as the base fiber, a composition for forming a joint sheet containing these fibers may be used. When kneading, the inorganic fibers are pulverized and the aspect ratio is lowered, resulting in a problem that the seal strength of the joint sheet obtained is lowered and the tensile strength is also inferior. There have also been attempts to form joint sheets by using only organic fibers as base fibers without using inorganic fibers, and by combining these organic fibers with fillers such as clay. There is a problem that the tensile strength of the joint sheet is small. Moreover, it has been found that the following problems exist in any of the above cases.

That is, when a composition for forming a joint sheet containing paid fibers, inorganic fibers such as glass, and fillers such as gray is heated and rolled using a hot roll and a cooling roll to adhere it to the hot roll in the form of a sheet, It has been found that the composition sometimes adheres to the cooling roll, resulting in poor processability and causing trouble in the manufacturing process. Also,
When the composition is hot-rolled using a hot roll and a cooling roll to adhere it in a sheet form to the hot roll, if the roll surface pressure or roll temperature changes, it becomes impossible to adhere the composition to a uniform thickness on the hot roll, resulting in a problem with the yield. It has been found that the thickness of the joint sheet produced by the joint sheet varies, resulting in loss of color.

In order to solve the above-mentioned problem that the joint sheet forming composition sticks to the cooling roll, it is essential to add an antistatic agent such as a surfactant to the joint sheet forming composition. Although the inventors have investigated this, there is a problem in that it is not necessarily preferable in terms of terms of incorporating an antistatic agent into a composition for forming a joint sheet.

The present inventors conducted extensive research to solve the problems associated with the above-mentioned conventional techniques all at once, and found that organic fibers such as aromatic polyamide fibers were The inventors have discovered that the above problems can be solved at once by using fibers and fibrous sepiolite in combination, and have completed the present invention.

OBJECTS OF THE INVENTION The present invention seeks to solve the problems associated with asbestos-free joint sheets, as described above.
When the composition for forming a joint sheet is kneaded, the inorganic fibers are not crushed and the aspect ratio is not reduced, so the tensile strength of the joint sheet is not reduced, and the composition for forming a joint sheet is not reduced. A joint that has excellent workability because the composition does not adhere to the cooling roll during IJ hot rolling of a product, and does not cause a decrease in workability even if the hot-pressed black tea 1'1 changes slightly. The purpose is to provide sheets.

Invention tl'! The joint sheet 1 according to the present invention is characterized in that it contains a fiber made of right+a fiber represented by aromatic polyamide fiber and sepiolite, a rubber material, and a rubber chemical. In some cases, in addition to the above-mentioned components, fillers such as polyolefin fibers, clay, mica, etc. may be included.

Since the joint sheet according to the present invention uses a combination V of organic fibers represented by aromatic polyamide fibers and sepiolite as the base fiber composition, the composition for forming the joint sheet is J5 does not adhere to the cooling roll, and workability does not decrease even if the hot rolling conditions change slightly, resulting in extremely excellent workability. Joint sheets with excellent mechanical strength such as tensile strength are preferred because they do not deteriorate.

DETAILED DESCRIPTION OF THE INVENTION The joint sheet according to the present invention consists of a base fiber consisting of right v1 fibers represented by aromatic polyamide fibers and sepiolite, a rubber material, and a rubber chemical. Explain in detail.

Organic fibers include aromatic polyamide fibers, fibrillated aromatic polyamide fibers, polyamide fibers,
Polyolefin fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyurea fibers, polyurethane 5AIi fibers, polyflu 40 carbon fibers, phenolic fibers, cellulose fibers, $11M1, etc. Conventionally, known i-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 iMIft (trade name Kevlar Pulp) are particularly preferred.

On the other hand, the sepiolite used together with the aluminum fiber as the base fiber has a diameter of 5 to 3000 μm, preferably 20 to 10 μm.
A material having fi & fiber length of approximately 0μ is used. This sepiolite is a hydrated magnesium silicate clay mineral, and is composed of silicon dioxide, magnesium oxide, calcium oxide, aluminum oxide, iron oxide, etc., and contains some attached moisture. This sepiolite is also
It has a so-called brick masonry structure, has great adsorption properties, and has unique rheological properties and consolidation properties.

Conventionally, such sepiolite has been used in the same way as montmorillonite for decolorizing and refining oil due to its adsorption properties, or as litter for pets such as dogs and cats;
Although it has been used as an excipient for pharmaceuticals, it has never been used in joint sheets in combination with organic fibers such as aromatic polyamide fibers.

It is preferable that the above-mentioned organic monofilament string such as aromatic polyamide [M] be used in a joint sheet in the form of 5 to 50 wt ω% type seedlings. For sepiolye 1, it is preferable to use 5 to 75% by weight of orange in the joint sheet. Further, it is preferable that the base fiber made of organic fiber and sepiolite is used in the joint sheet at a weight of 10 to 85% by weight.

In some cases, a small amount of non-v1 fibers can also be used in addition to the above-mentioned base material M&K. Such pi-woven fibers 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 Zirnia fiber,
Ia-free fibers known as conventional base material 5AIi fibers for forming joint sheets, such as boron nitride fibers, alkali titanate mM, 1 Quisker, boron fibers, carbon fibers, and metal fibers, are widely used. In addition, as inorganic II according to the present invention,
It can also contain small amounts of asbestos fibers.

The rubber material binds the above fibers t4 (Q WIJ), and includes nitrile rubber (N8R>, 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 (C3M), ethylene vinegar rubber (EVA), chlorinated polyethylene (CPE)
, TN butyl rubber (CIR), Ebichlor ditritin rubber (ECO), Nitrile isoprene rubber (NIR>
Conventional rubbers such as natural rubber (NR) are widely used as the rubber for forming the joint sheet.

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, this Jζ oil-extended rubber and the above-mentioned rubber materials can be used in combination.

This rubber material has a suspension of 10 to 401% in the joint sheet.
Preferably used in ].

Rubber chemicals include fi) vulcanizing agents such as sulfur, zinc oxide, magnesium oxide, peroxide, and dinitrosobenzene;
(ii) A vulcanization accelerator such as a thiazole compound, a polyamine compound, a sulfenamide compound, a didiocarbamate compound, an aldehyde amine compound, a guanidine compound, a thiourea compound, or a xanthate compound is used. .

In addition, filling +, 4 can be used as needed in addition to 7Jn in rubber chemicals, and such fillers include clay,
Talc, barium sulfate, heavy carbon wortium, graphite, IKI M spear, 1-lipoli stone, etc. are widely used. These rubber chemicals J5 and fillers are conventionally known for forming joint sheets.

Q: Is this rubber chemical used in the joint sheet at a concentration of 0.5 to 20%? Delicious.

Further, it is preferable that the filler is used in an amount of 0 to 80 I%.

Next, a method for manufacturing a joint sheet according to the present invention will be explained.

Rubber material is dissolved in a rubber material solvent such as toluene or rubber solvent, and rubber chemicals are mixed into this. A mixture of fibers such as aromatic polyamide WCAT and sepiolite is blended into the solution or dispersion and kneaded uniformly to prepare a clay-like composition for forming a joint sheet. 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, it is preferable that the heating roll is kept at a temperature of 120 to 160'C and the cooling roll is kept at a temperature of 50'C or less.A device including such a pair of rolls is known as a sheeter device. It is.

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 Sea 1~-shaped composition is peeled off from the hot roll,
19 joint sheets are removed.

Note that 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 using aromatic polyamide fibers and sepiolite as the base fibers rarely adheres to the cooling roll during molding, and even if it does adhere to the cooling roll, It can be easily removed by pouring water onto a roll, and therefore has excellent workability, and has the following great effect: 1) There is no waste of the composition. Therefore, it is not necessarily necessary to add an antistatic agent to the joint sheet forming composition.

In addition, prevention of adhesion of the join 1 to sheet forming composition to the cooling roll can be enhanced by adding 41 antistatic agent to the composition in the amount of 0.1 to 10 wt ω% type seedlings. can. 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.

Further, when hot rolling the composition for forming a joint sheet with a pair of rolls, the workability does not deteriorate even if the hot rolling conditions vary slightly, and a joint sheet having uniform thickness and properties can be obtained.

In this way, the joint sheet according to the present invention has a significantly lower tensile strength than the case where glass fiber A1 is used instead of sepiolite.

In addition, when Sepi A-Lye 1~ is used as 73, +4 fiber, this reviolite may be due to the adsorption V1.
The rubber solvent contained in the composition for forming a joint sheet is difficult to evaporate when heated, and therefore the composition for forming a joint sheet I is difficult to dry. JJ[] 7Jfl workability is good when hot rolling.

Effects of the Invention Since the joint sheet according to the present invention uses a combination of organic fibers such as aromatic polyamide fibers and sepiolite as the base fiber composition, the composition for forming the joint sheet is Materials do not stick to the cold ft0L + - roll, and workability does not decrease even if the JJO heat pressure and heat pressure conditions change slightly, so it has excellent workability and does not cause the biolite to break. What is the aspect ratio?
Examples of the present invention (from this 1) 1 Light is limited to these Examples., Example 1 Formation of a joint sheet with hT of the following composition. for τ[1
The product was manufactured by A.

Sepiolite ・・・・・・ε3. ○Φearly(
, ¥.

(Fiber length 50μ) Fibrillated...10.8 out of jj
'#(1 Aromatic polyamide fiber NBR...15.9 dry, T% Rubber chemical (vulcanizing agent)...2.3Φcloth':
3 also full li material...63.0j
, D cloth % (middle leg, clay) Toluene ・・・・・・1k of the above mixture
The resulting composition was heated to a temperature of 130"C and heated to a temperature of 30"C.
It was inserted between cooling rolls kept at ℃ and heated and 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 heated roll using a doctor blade to obtain a joint sheet with a thickness of 1.5 mm (q).

At this time, no adhesion of the joint sheet forming composition to the cooling roll was observed. Therefore, there was no need to use an antistatic agent in the joint sheet forming composition.

Tensile strength (kgf/cm2) in the 111 direction, compression ratio (%), recovery ratio (%), density (+I
I/cm3), flexibility (thickness magnification), maximum loading line pressure (
kc+/cn+) was measured and the results are shown in Table 2.

In addition, the sealing properties of the obtained joint sheets were measured and ranked as follows, and the results are shown in Table 2. Insert this cassette between the flange faces and
After injecting with KFi/cm, nitrogen of 15 to 3/C was injected into the inside and left for 1 minute. Apply soapy water to the outer surface of the gasket, leave it for 2 minutes, and then observe the degree of leakage and rank it as shown in Table 1 below. The sealing properties of Kasget were evaluated.

Example 2 Join 1 to d3 in Example 1 and having the following composition
A joint sheet was formed in the same manner as in Example 1 except that the sheet forming composition was used.

Sepiolite...30.7 weight% (
Fiber length 50μ) Fibrillated...10.4% by weight aromatic hexagroup polyamide fiber\BR...15.4% by weight Rubber chemicals (1) 0 sulfur based mulberry agent)... ... 2.1 double maximum% Koukai Shrine ...41.4 double chant%
(Midway, clay) Toluene: 1 kg of the above mixture
Example 1
Measurements were made in the same manner as above, and the results are shown in Table 2.

In addition, the seal characteristics TL of the joined sheets 1 to 1 which were turned away were measured and ranked in the same manner as in Example 1, and the results are shown in Table 2.1゜Example 3 In Example 1, the following composition A joint sheet was formed in the same manner as in Example 1, except that the composition for forming a joint sheet was used.

Sepiolite...15.6% by weight (fiber length 50μ) Fibrillated...10.6% by weight Aromatic polyamide w4 sets NBR...15.6'&r;% Rubber chemicals...2.2 small Amount % (vulcanizing chemicals) Filler: 56.0 small (8% (middle leg, clay) Toluene: 0.7 layers of υ1 jointed jonite sheet per 1 kq of the above mixture [Example of tensile strength etc.]
It was measured in the same manner as 1, and the results are shown in Table 2.

Also! The seal retention on the joint seam 1" was measured and ranked in the same manner as in Example 1, and the results are shown in Table 2.

Example 4 In Example], a joint sheet was formed in the same manner as in Example 1, except that a composition for forming a joint sheet having the following composition was used.

Sepiolite...15.6fflΦ% (fiber length 50μ) Fibrillated...10.6% by weight Aromatic polyamide fiber NBR...15.6% Rubber chemicals...2.2% by weight (added) Sulfur-based chemicals) Fillers...56. O weight% (severe,
Clay) Toluene... Example of the tensile strength of the John 1 sheet to which 1q was added at a ratio of 0.71 to 1kq of the above mixture]
It was measured in the same manner as above, and the ¥21 song value is shown in Table 2.

Also jqed join 1 ~ sheet seal 1) 1 no 1
were measured and ranked in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 1 A joint 1 sheet-forming field silk composition having the following composition was prepared, and a joint sheet was formed in the same manner as in Example 1.

Glass fiber...15.6 small ω% fibrillated...10.6Φ amount% aromatic polyamide 1
~Fiber NBR...15.6 heavy fabric% Rubber mulberry crystal...2.2Φ suspension% (vulcanizing chemicals) Filler...54.8 heavy fabric% (jucharoum,
(clay) Antistatic agent: 1.2% (Cortamine) Incidentally, when an antistatic agent is not used in the joint sheet forming composition, the composition ends up being subjected to cooling rolls.

The tensile strength and other properties of the obtained joint sheet were measured in the same manner as in Example 1, and the results are shown in Table 2.

In addition, the sealing properties of the joint sheets obtained were measured and ranked in the same manner as in Example 1, and the results are shown in Table 2.
Shown below.

Claims (5)

[Claims] (1) A joint sheet comprising a base fiber made of organic fibers and sepiolite, a rubber material, and a rubber chemical. (2) The joint sheet according to claim 1, wherein the organic fiber is an aromatic polyamide fiber or a fibrillated aromatic polyamide fiber. (3) The joint sheet according to claim 1, wherein the sepiolite is fibrous and has a length of 5 to 3000 μm. (4) 5 to 50% by weight of organic fibers in the joint sheet
The joint sheet according to claim 1, wherein the joint sheet is used in an amount of . (5) The joint sheet according to claim 1, wherein sepiolite is used in the joint sheet in an amount of 5 to 75% by weight.