JPH02308841A - Fluororubber composition - Google Patents

Abstract

PURPOSE:To obtain a composition, consisting essentially of a fluororubber and organic rubber and capable of providing crosslinked products excellent in extrudability, processability, heat, oil resistance, etc., and suitable as sealing materials, diaphragms, etc., in transports, such as automobiles and ships. CONSTITUTION:A fluororubber composition obtained by blending 100 pts.wt. total amount of (A) 95-99.5 pts.wt. fluororubber (e.g. vinylidene fluoride- hexafluoropropylene copolymer) having preferably 30-150 Mooney viscosity and (B) 0.5-5 pts.wt. organic rubber having 10-200 Mooney viscosity other than the fluororubber with (C) a crosslinking agent [e.g. sulfur (derivative) or organic peroxide] for the organic rubber of the component (B). Furthermore, (D) a crosslinking agent for the fluororubber of the component (A) is blended and reacted while applying shearing deformation thereto.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a fluororubber composition, and more specifically, the present invention relates to a fluororubber composition that has extrudability, processability, heat resistance, oil resistance, The present invention relates to a fluororubber composition and a crosslinkable fluororubber composition capable of providing a crosslinked product with excellent weather resistance, compression set resistance, and compression load resistance.

(Conventional technology) In recent years, the requirements for the performance of rubber materials have become stricter year by year, and the types of rubber materials used are also changing. Among rubbers, fluororubbers are highly resistant to solvents and heat. It has outstanding performance compared to other special rubbers in terms of hardness, chemical resistance, and surface weatherability, and its demand is increasing year by year in the fields of industrial products, automobiles, and aircraft.

However, compared to other organic rubbers, fluororubber is difficult to process efficiently, and especially when extrusion molded fluororubber is made into a molded product, it tends to expand after passing through the die. As a result, a molded body much larger than the size of the base is produced. As described above, since fluororubber has a large mold expansion, it is extremely difficult to extrude and mold products with complicated cross sections. Therefore, when extrusion molding fluororubber, it is necessary to use a wax-type extrusion molding aid and select an extrusion molding device that can provide a high extrusion temperature of about 20°C. There were problems such as the body would have a rough appearance.

Furthermore, JP-A-62-4708 discloses a method for improving extrudability by partially crosslinking a fluoroelastomer of vinylidene fluoride and a fluorine-containing monomer that can be copolymerized with vinylidene fluoride and mixing it with fluororubber. has been proposed, but this method cannot substantially reduce product expansion during extrusion molding, and the surface appearance of the extruded product is also poor.

[Problem to be solved by the invention]

The present invention was made against the background of the above-mentioned conventional technical problem, and when blending fluororubber and an organic rubber other than fluororubber, the organic rubber is dispersed by substantially crosslinking only the organic rubber. To provide a fluororubber composition that reduces the particle size and increases the mutual penetration of molecules at the interface of both rubbers, prevents interfacial peeling, and has excellent extrudability and processability. It is an object of the present invention to provide a crosslinkable fluororubber composition which has excellent normal physical properties, heat resistance, oil resistance, compression set resistance, and compression load resistance of a crosslinked product obtained by crosslinking.

[Means for Solving the Problems] The present invention provides fluororubber (1) containing more than 99.5 parts by weight of fluororubber (1).
Parts by weight or less, and organic rubber other than fluororubber (hereinafter simply referred to as "organic rubber") (■) 0.5 parts by weight or more but less than 5 parts by weight (however, (1) + (II) - 100 parts by weight) ,
A fluororubber composition obtained by blending an organic rubber (]]) crosslinking agent (hereinafter referred to as "crosslinking agent (■)") and reacting while applying shear deformation (hereinafter simply "fluororubber composition")
).

Further, the present invention provides a method for adding fluororubber (I) to this rubber composition.
The present invention provides a crosslinkable fluororubber composition (hereinafter referred to as "crosslinkable fluororubber composition") containing a crosslinking agent (hereinafter referred to as "crosslinking agent (1)").

The fluororubber (1) in the present invention is obtained, for example, from a combination of the following fluorine-containing monomers.

That is, the fluororubber (1) includes vinylidene fluoride, hexafluoropropene, pentafluoropropene, trifluoroethylene,
Trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoro (methyl vinyl ether), perfluoro (propyl vinylidene), etc. are used, and monomers that can be copolymerized with these include vinyl compounds such as acrylic esters, propylene, etc. Examples include rubbers copolymerized with olefin compounds or diene compounds, and halogen-containing vinyl compounds containing chlorine, bromine, and iodine.

Specific examples of the fluororubber (1) include vinylidene fluoride-propylene hexafluoride copolymer, vinylidene fluoride-propylene hexafluoride-ethylene tetrafluoride terpolymer, and ethylene tetrafluoride-propylene copolymer. , ethylene tetrafluoride-vinylidene fluoride-propylene terpolymer, and the like.

Mooney viscosity (ML, .4.100 of fluororubber (1)
'C) is not particularly limited, but preferably 3
0 to 150 is used.

Next, examples of the organic rubber (II) include diene rubber, ethylene-α-olefin-(diene) rubber, acrylic rubber, halogenated polyethylene rubber, and shrimp-halohydrin rubber.

Specific examples of this organic rubber (1) include ethylene-propylene rubber (EP(D)M:l), natural rubber (NR)
, isoprene rubber (TR), chloroprene rubber (CR)
, styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR)
), acrylic rubber (AR, ethylene-acrylic rubber,
ethylene-vinyl acetate-acrylic rubber), hydrin rubber (Co, EC0), chlorosulfonated polyethylene (
CM, C3M), ethylene-vinyl acetate rubber (EVA
), preferably BP(D)M,,I
TR is acrylic rubber.

The organic rubber (It) includes a halogen atom, a copolymer of an unsaturated carboxylic acid compound such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, allyl glycidyl ether, and a part of an aliphatic conjugated diene moiety. Alternatively, it may be entirely hydrogenated.

In addition, the organic rubber (II) has a Mooney viscosity (ML
+-4,100°C) is 10 to 200, preferably 20
~150, more preferably 30~], OO is suitable, and by using the organic rubber (II) having such a Mooney viscosity, it is possible to obtain a fluororubber composition having stable quality and properties. can. If the Mooney viscosity of the organic rubber (TI) is outside the above range, kneading workability and dispersibility will deteriorate, making it difficult to maintain quality characteristics.

The weight ratio of fluororubber (1) and organic rubber (I[) in the fluororubber composition of the present invention is such that fluororubber (1) is 9
More than 5 parts by weight and less than 99.5 parts by weight, preferably 1 to 4 parts by weight
parts by weight, organic rubber (II) is 0.5 parts by weight or more and less than 5 parts by weight, preferably 96 to 99 parts by weight [However, (1)
+ (II) = 100 parts by weight], if the fluororubber (1) is less than 95 parts by weight, the heat resistance, which is a characteristic of fluororubber, will be inferior, while if it exceeds 99.5 parts by weight, the compressive load resistance will be poor. The improvement in extrudability is also insufficient.

Next, in the present invention, when mixing the fluororubber (1) and the organic rubber (II) and crosslinking the organic rubber (II), in addition to the crosslinking agent (II) of the organic rubber (]]), if necessary, A crosslinking accelerator, crosslinking aid, acceleration aid, crosslinking retardant, etc. may be used in combination.

As this crosslinking agent (11), organic rubber (II) is usually used.
These include all used as crosslinking agents. Examples include sulfur or its derivatives, organic peroxides, resin vulcanizing agents, quinoid vulcanizing agents, and the like. Specifically, a system is selected in which the organic rubber (1) is crosslinked and the fluororubber (1) is difficult to crosslink.

Examples of the organic peroxide used as a crosslinking agent include 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(t-
butylperoxy)hexane, α,α′-bis(t-butylperoxy)-p-diisopropylbenzene, dicumyl peroxide, di-t-butyl peroxide,
t-Butyl peroxybenzoic acid I, 1,1-bis(
(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobensyyl peroxide, etc., preferably 2,5-dimethyl-2 ,5-di(t-butylperoxy)hexyne-3
, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, α1 α'-bis(t-butylperoxy)-P-diisobrobylbenzene.

In the case of sulfur, the amount of these crosslinking agents (II) added is 0.01 parts by weight per 100 parts by weight of the fluororubber composition of the present invention.
~10 parts by weight, preferably 0. 5 to 5 parts by weight,
In the case of the organic peroxide, the amount added is as follows: Rubber composition 1
0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight. If the amount of crosslinking agent (II) used is too small, the crosslinking density of the rubber component will be low, resulting in poor mechanical strength and
Oil resistance and creep resistance will be insufficient, while if the amount is too high, the crosslinking density of the rubber component will become too high, and the elongation of the crosslinked product of the resulting crosslinkable fluororubber composition will decrease.

In addition, when crosslinking organic rubber (II) with organic peroxide,
A difunctional vinyl monomer or the like can be used as a crosslinking aid. The selection of the crosslinking aid depends on the organic rubber used (
■) Determined by the type of rubber, specifically organic rubber (■■)
A system that crosslinks the fluororubber (1) and is difficult to crosslink the fluororubber (1) is selected.

Examples of this crosslinking aid include the following compounds. That is, ethylene glycol dimethacrylate-I.,1
, 3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate-1-, 1,4-butanediol diacrylate 1-11,6-hexanediol diacrylate, 2゜2'-bis(4-methacryloyljethoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate,
Pentaerythritol triacrylate, divinylbenzene, N,N'-methylenebisacrylamide, p-
Quinonedioxime, p.

These include p'-dibenzoylquinone dioxime, triazinedithiol, triallylcyanurate, triallylisocyanurate, bismaleimide, and the like.

The amount of this crosslinking aid used is as follows:
The amount is usually 0.1 to 20 parts by weight, preferably 0.5 to 7 parts by weight.

In the present invention, fluororubber (1) and organic rubber (II)
There are no particular restrictions on the method of adding a crosslinking agent to the
Component (1), component (II), and crosslinking agent (II) can be added and kneaded simultaneously, or components (1) and (II) can be mixed in advance, and then crosslinking agent (II) can be added. You can also add

Mixing is carried out by using a variety of extruders, Banbury mixer 11, kneading with rollers, etc. at a temperature of 50 to 250°C, preferably 100 to 200°C, for 1 hour; 2 minutes to 1 hour, preferably 3 minutes to 45 minutes. A preferred kneading method is a method using an internal mixer such as a Banbury mixer or a kneader.

At this time, if crosslinking occurs at a kneading temperature of less than 50°C, it will be difficult to control the reaction, while if the kneading temperature exceeds 250'C, the rubber will tend to deteriorate.

Moreover, if the kneading time is shorter than 2 minutes, it will be difficult to control the reaction and it will be difficult to obtain a uniform composition, while if it exceeds 1 hour, the kneading cost will increase, which is not preferable.

Note that the kneading temperature when adding the crosslinking agent is usually 10
~200°C1 preferably 20-150'C,
In the case of organic peroxides, it is preferred that their half-life is below 1 minute temperature.

As described above, the crosslinking in the present invention must be performed during mixing.

That is, during mixing, shearing force is applied to the elastomer, so fluororubber (1) or organic rubber (
This is because the dispersed particles in II) remain smaller and more molecules are entangled at the interface.

In this case, when you stop applying shearing force, the fluororubber (
1) Alternatively, the dispersion particles of organic rubber (II) will associate with each other, increasing the particle size and reducing molecular entanglement.

In this way, by crosslinking the organic rubber (TI) at the same time as mixing, the system can be fixed in a well-dispersed state.

In addition, the fluororubber composition of the present invention comprises (1) to (II)
Although these ingredients are the main ingredients, various commonly used compounding agents can be added in addition to these ingredients.

These compounding agents may be added as necessary during the process of producing the fluororubber composition of the present invention, or may be added when producing the crosslinkable fluororubber composition after producing the composition. .

That is, examples of reinforcing fillers and extenders include carbon black, fumed silica, wet silica, fine quartz powder, diatomaceous earth, zinc white, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, Mention may be made of talc, mica powder, aluminum sulfate, calcium sulfate, barium sulfate, asbestos, graphite, wollastonite, asbestos disulfide, polytetrafluoroethylene, glass fibers, organic reinforcing agents, and organic fillers.

Dispersion aids include higher fatty acids and their metal amine salts; plasticizers include, for example, phthalic acid derivatives, adipic acid derivatives, and sebacic acid derivatives; softeners include, for example, lubricating oil, process oil, coal tar, castor oil, Calcium stearate; As an anti-aging agent, for example, phenylene diamines, phosphate! , quinolines, cresols, phenols, dithiocarbame-1 metal salts, hindered amines; other colorants, ultraviolet absorbers, flame retardants, foaming agents, scorch inhibitors, tackifiers,
Lubricants etc. can be added as desired.

These fluororubber compositions are mixed with a crosslinking agent (I), which is a crosslinking agent for fluororubber (1), such as an organic peroxide, a crosslinking aid, and a polyol, using a common kneading machine such as a roll or banhari mixer. After adding and kneading a crosslinking agent, a crosslinking accelerator, and an amine crosslinking agent to produce a crosslinkable fluororubber composition, it is molded and crosslinked under normal crosslinked rubber manufacturing conditions to produce a crosslinked rubber product. I can do it.

Here, as the polyol crosslinking agent, polyhydroxy aromatic compounds such as hydroxyl, bisphenol A
, bisphenol AF and their salts are preferably used. Further, fluorine-containing aliphatic diols can also be used.

The amount of these polyol crosslinking agents added is usually 0.1 to 20 parts by weight per 100 parts by weight of the fluororubber composition.
Preferably, the amount is about 1 to 10 parts by weight.

In addition, as a crosslinking accelerator, quaternary ammonium compounds such as methyltrioctylammonium chloride, henzyltriethylammonium chloride, and 1-rahexylammonium tetrafluoroborate; 8-methyl-1,8-diaza-cyclo(5 , 4,0)-7-Unzocenyl chloride; hensyl 1-riphenylphosphonium chloride, m-1-lifluoromethylbenzyltrioctylbosphonium chloride, benzyltrioctylphosphonium bromide; Quaternary phosphonium compounds such as the like are preferred.

The amount of the crosslinking accelerator added is usually 0.2 to 10 parts by weight per 100 parts by weight of the fluororubber composition.

Furthermore, examples of amine crosslinking agents include various alkyl amines such as hexamethylene diamine, tetraethylene pentamine, and l-lyethylene tetramine, various aromatic amines such as aniline, pyridine, and diaminohenzene, and carbamines of these amines. Acids, salts of fatty acids such as cinnamylidenic acid, etc. can be used.

The amount of this amine crosslinking agent added is 10% of the fluororubber composition.
0 parts by weight, usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight. It is about 5 to 5 parts by weight.

In the present invention, specific examples of the crosslinking agent (1) include the following combinations.

■ Fluororubber (1) is a vinylidene fluoride-propylene hexafluoride copolymer and/or a vinylidene fluoride-propylene hexafluoride-ethylene tetrafluoride terpolymer with a diene compound, chlorine atom, bromine atom or In the case of a fluororubber copolymerized with a halogen-containing compound containing an iodine atom and/or a vinylidene fluoride-propylene-tetrafluorinated ethylene terpolymer, the crosslinking agent (1) is
Examples include (1) diamine crosslinking agents, (2) polyol crosslinking agents, and (3) organic peroxides and crosslinking aids.

■When the fluororubber (1) is a vinylidene fluoride-propylene hexafluoride copolymer and/or a terpolymer of vinylidene fluoride-propylene hexafluoride-ethylene tetrafluoride, the crosslinking agent (1) is ( Examples include 1) diamine-based crosslinking agents, (2) polyol-based crosslinking agents, and the like.

(2) When the fluororubber (I) is a tetrafluorinated ethylene-propylene copolymer, examples of the crosslinking agent (1) include only a combination of an organic peroxide and a crosslinking aid.

Crosslinking of the crosslinkable fluororubber composition obtained in this way is usually carried out at 80 to 200'C for several minutes to 3 minutes.
primary crosslinking under pressure of 20 to 200 kg/cJ for
Further, if necessary, secondary crosslinking is performed at 80 to 200'C for 1 to 48 hours to obtain a crosslinked rubber product.

As described above, the fluororubber composition of the present invention can be uniformly kneaded using a kneading device such as the Banbury mixer or the three-roll kneader described above. In addition, when adding crosslinking agents, crosslinking accelerators, etc. using rolls, simply using a mixture of fluororubber and organic rubber (including mixtures of fillers and other additives), it takes a lot of time to wind the rolls. However, the fluororubber composition of the present invention can be rolled up instantly, and the workability is significantly improved.

Furthermore, the crosslinked rubber product (rubber elastic body) obtained by crosslinking the crosslinkable fluororubber composition of the present invention has excellent heat resistance, oil resistance, weather resistance, compression set, and compression load resistance.
It can be used in general industry, electricity, and chemical fields.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, various measurements in the examples were based on the following methods.

The test conditions for the extrusion property test were evaluated by the following method.

Extruder; Manufactured by Imao Kikai Kogyo ■, using Garbe die for 50mmφ rubber L/D = 12 Extrusion conditions: Temperature Hopper - 50°C Cylinder =
60°C Head - 70°C Screw rotation speed - 15 rpm In this extrusion characteristic test, the extrusion amount (length) is the length extruded in 1 minute, the extrusion amount (weight) is the amount extruded in 1 minute, Dice well has a cross-sectional area of 0.53c
The extruded skin was evaluated using a ffl Garhedai, and the extrusion skin was evaluated as O1 for those with a smooth surface and × for those with uneven surfaces.

In addition, initial physical properties, aging test, compression set test are JIS
Evaluation was made in accordance with K6301 under the conditions shown in Table 1.

Examples 1 to 14 According to the formulation shown in Table 1, fluororubber (1), organic rubber (■), and processing aid (sodium stearate) were sequentially mixed in a rubber mixer (50 to 150°C, 1C, 160r
When the mixture becomes homogeneous, Percadox 1, which is an organic peroxide, is added as a crosslinking agent (II).
4 [α,α′-bis(t-butylperoxy)-p-diisoprobylhenzen, manufactured by Kayaku Nouri ■, Examples 1~
6.9 to 14], Parnock AB (ammonium benzoate, manufactured by Iriuchi Shinko Chemical Co., Ltd., used in Example 8), Tackirol 250-1 (alkyl 1!11 phenol formaldehyde resin, manufactured by Sumima Chemical Co., Ltd., used in Example 8) (Used in Example 7) and triallylisocyanure-1 (manufactured by Nippon Kasei ■, used in Example 12) as a crosslinking aid were added and kneaded, and after becoming homogeneous again, the temperature was raised to 17.
After raising the temperature to 0 to 180°C and making the kneading torque and rubber temperature almost constant (after about 10 to 20 minutes), Tsukrac CD (manufactured by Iriuchi Shinko Kagaku Kogyo ■) as an anti-aging agent was added.
MT carbon as a filler (Examples 1-10.12-1
4), Nibseal LP (manufactured by Nippon Silikani Industry ■, used in Example 11), and silane coupling agent TSL
8370 (γ-glycidoxypropyltrimethoxysilane, manufactured by Toshiba Silicone ■, used in Example 11) was further kneaded, and after the mixture became uniform again, it was discharged.

Next, the sheet obtained in this way was wound around two rolls again, and other compounded chemicals such as crosslinking agent (1) and crosslinking aid shown in Table 1 were added and kneaded.
Press crosslinking (100-150kg/cIfl, 17
After heating and pressurizing at 0°C for 20 minutes, secondary crosslinking was performed in an oven at 200°C for 4 hours, and the crosslinking properties were measured.

The results are also shown in Table 1.

Comparative Examples 1 to 2 Organic rubber (
A fluororubber composition was produced and evaluated in the same manner as in Example 1, except that the crosslinking agent (II) added for the purpose of crosslinking II) was not blended.

The results are shown in Table 1.

Comparative Example 3 A fluororubber composition was produced and evaluated in the same manner as in Example 1, except that only JSR Afras 150P, which is fluororubber (1), was used as the rubber component and no organic rubber (II) was blended.

The results are shown in Table 1.

(Left below) *1) Tetrafluoroethylene-propylene copolymer rubber *2) Vinylidene fluoride-hexafluoropropylene copolymer rubber *3) Ethylene-propylene rubber *4) Hydrin rubber *5) Acrylic rubber * 6) Styrene-butadiene rubber *7) Polybutadiene rubber *8) Acrylonitrile-butadiene rubber *9) Butyl rubber *10) Acrylic rubber *11) Ethylene-vinyl acetate co-M combination *12) Chlorosulfonated polyethylene [Effects of the invention] The fluororubber composition of the present invention has excellent roll processability and easy molding processability compared to a simple mixture of fluororubber and organic rubber, and is a crosslinkable fluororubber composition. Crosslinked products obtained by crosslinking materials also have excellent heat resistance, compression set properties, and A compression load resistance.

Because the crosslinked fluororubber product of the present invention has such characteristics, it can be used as oil-resistant, chemical-resistant, heat-resistant, steam-resistant, or weather-resistant backings, O-rings, bows, etc. in transportation facilities such as automobiles, ships, and aircraft. seals, diaphragms, valves, and similar backings, rings, seals, diaphragms, etc. in chemical plants.
Valves, hoses, rolls, tubes, chemical-resistant coatings, linings, and similar backings, O-rings, hoses, seals, belts, diaphragms, valves, rolls, in food plant equipment and food equipment (including household items). Similar backings, O-rings, hoses, seals, diaphragms, valves, tubes, similar backings, O-rings, hoses, seals, diaphragms, valves, similar backings, O-rings, hoses, seals, diaphragms, valves, tubes, O-rings, hoses, seals, etc.
It is suitable for use in diaphragms, valves, rolls, tubes, linings, mandrels, electric wires, flexible joints, healds, rubber plates, weather strips, roll blades for PPC copying machines, and the like.

Furthermore, specific applications include: (a) In the automotive industry, ■Sealing applications: * Core valves for carburetor needle valves, * Flange gaskets for carburetor brakes, * Power piston gaskets, * O-rings for automobile gasoline mixing pumps. , *Cylinder liner seal, *Valve stem seal, *Front pump seal of automatic transmission, *Rear axle pinion seal, *Universal joint gas connector, *Speedometer pinion seal, *Piston force of foot brake. *Torque transmission O-ring, oil seal, *Exhaust gas re-burning device seal, *Bearing seal, *Gasoline pump O-ring, *Gasoline hose seal, b *Seal for car air conditioner, ■Hose application *Fuel hose, *EGR tube, *Twin carb tube, ■Diaphragm applications: *Gasoline pump diaphragm, *Carburetor sensor diaphragm, ■Other applications: *Vibration isolation rubber (engine mount, exhaust section, etc.) , *Hoses for afterburning equipment, (b) In the chemical industry, ■Sealing applications include: *Chemical pumps, rheometers, seals for piping, *Seals for heat exchangers, *Backing for glass coolers in sulfuric acid production equipment. , *Seals for pesticide sprayers and pesticide transfer pumps, *Seals for gas pipes, *Seals for plating liquids, *Packskins for high-temperature vacuum dryers, *Coroseal for papermaking belts, *Seals for fuel cells, *Joints for wind tunnels. Seals, ■Roll applications: *I-resistant/recleaning rolls (for textile dyeing), ■Lining and coating applications: *Corrosion-resistant lining for alumite processing tanks, *massing jig coating for plating, *gasoline tank lining, * Wind tunnel lining, ■Other uses include: *Acid-resistant hose (for concentrated sulfuric acid), *Gas chroma I-graph, packing for P+-1 meter tube joints, *Chlorine gas transfer port, *Oil-resistant hose, *Hensen, Rainwater drain hoses for toluene storage tanks, * Flue expansion joints (coated with ashesto cloth), (c) For general machinery, ■ Seal applications include: * Seals for hydraulic and lubricating machines, * Bearing seals, * Dry-type copying machines. seals, *Windows and other seals for dry cleaning equipment, *Seals for uranium hexafluoride enrichment equipment, *Seals for cyclotrons (vacuum) valves, etc., *Seals for automatic packaging machines, ■Other uses include: *Dry copying. Machine belts, *Pump diaphragms (pollution measuring instruments) for analyzing sulfur dioxide and chlorine gas in the air, *Snake bomb lining, *Printing press rolls, Peru, *Squeezing rolls for pickling, (d) Aircraft-related ＊Jet engine valve stem seals, ＊Fuel supply hoses, gaskets and O-rings ＊Rowing shaft seals, ＊Hydraulic equipment gaskets, ＊Firewall seals, (e) For ships, ＊Screw propeller shafts. Stern seal, *Diesel engine intake/exhaust) <rubustem seal, *Butterfly valve valve seal, *Butterfly valve shaft seal, (f) Food and medical related products, *Brae 1~ type heat exchanger seal, *Solenoid valve seals for vending machines, *Medicine stoppers, (g) In the electrical field, *Insulating oil caps and knobs for Shinkansen trains, *Henching seals for liquid-sealed transformers, *Shakes and nuts for oil well cables, etc. One example is usage.

Patent applicant: Japan Synthetic Rubber Co., Ltd. Agent: Patent Attorney Takashi Shirai 2 days

Claims (2)

[Claims] (1) More than 95 parts by weight of fluororubber (I) and less than 99.5 parts by weight, and more than 0.5 parts by weight and less than 5 parts by weight of organic rubber (II) other than fluororubber [However, (I) + (II) =1
00 parts by weight] and a crosslinking agent for organic rubber (II), and the mixture is reacted while being subjected to shear deformation. (2) Fluororubber (I) is added to the rubber composition according to claim 1.
) A crosslinkable fluororubber composition containing a crosslinking agent.