JPH05117479A - Fluorocarbon rubber composition - Google Patents

Abstract

(57) [Summary] [Structure] 5 to 70 parts by weight of a nitrile rubber (1) containing a gel content of 30% by weight or more insoluble in methyl ethyl ketone,
A fluororubber composition obtained by blending 95 to 30 parts by weight of a fluororubber (2) with the crosslinking agent of (1) and reacting while giving shear deformation. [Effect] The fluororubber composition of the present invention provides a fluororubber composition having excellent compatibility and processability, and a well-balanced performance and price.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororubber composition having excellent processability, which comprises a nitrile rubber containing a gel content of 30% by weight or more insoluble in methyl ethyl ketone and a fluororubber as main components.

[0002]

2. Description of the Related Art In recent years, the demands on the performance of rubber materials have become stricter year by year, and the types of rubber materials used have changed. Among rubber, fluororubber is
It has outstanding performance in solvent resistance, heat resistance, chemical resistance, and weather resistance compared with other special rubbers, and its demand is increasing year by year in the fields of industrial goods, automobiles and aircraft. However, the price thereof is extremely expensive as compared with elastomers other than fluororubber, and the specific gravity thereof is high, which causes a marked increase in product price, and thus the field of use has been limited.

Thus, it can be said that it has become difficult to meet the contradictory requirements of high performance and low price with one kind of rubber material. To meet such demands, a method of mixing fluororubber with an elastomer other than fluororubber has been proposed. For example, as disclosed in Japanese Patent Application Laid-Open No. 190739/1989, there is an attempt to improve the compatibility between nitrile rubber and / or chloroprene rubber and fluororubber, but its processability, particularly extrusion processability, is still unsatisfactory. I have to say that it is enough.

[0004]

SUMMARY OF THE INVENTION The present invention has been made against the background of the above-mentioned conventional technical problems, and the compatibility between nitrile rubber and fluororubber is remarkably improved, and the fluororubber composition is excellent in processability. The purpose is to provide goods.

[0005]

According to the present invention, 5 to 70 parts by weight of a nitrile rubber (1) containing a gel content of 30% by weight or more insoluble in methyl ethyl ketone (hereinafter simply referred to as "nitrile rubber (1)") is used. And a cross-linking agent for the nitrile rubber (1) in 95 to 30 parts by weight of the fluororubber (2), and reacting while applying shear deformation.

The nitrile rubber (1) in the present invention is a rubber containing acrylonitrile, for example (a)
At least one aliphatic conjugated diene such as 1,3-butadiene and 2-methyl-1,3-butadiene is used in an amount of 15 to 70.
% By weight, (b) 10 to 50% by weight of acrylonitrile,
(C) 0 to 75% by weight of acrylic acid ester and / or methacrylic acid ester, and (d) divinylbenzene, diallyl phthalate, diallyl mer having a plurality of double bonds in the molecule for containing a gel component in nitrile rubber. Rate, trimethylolpropane triacrylate 1 to 5% by weight (however, (a) + (b) + (c) +
An intermolecular crosslinked product obtained by copolymerizing (d) = 100% by weight) can be mentioned.

Examples of the (meth) acrylic acid ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-butyl methacrylate, isobutyl methacrylate. , Pentyl acrylate, pentyl methacrylate, hexyl acrylate,
Hexyl methacrylate, heptyl acrylate, heptyl methacrylate, 2-ethylhexyl acrylate, octyl acrylate, octyl methacrylate, n-nonyl acrylate, isononyl acrylate, n-nonyl methacrylate, isononyl methacrylate, decyl acrylate, methacrylic acid Decyl, undecyl acrylate, dodecyl methacrylate, n-amyl acrylate, isoamyl acrylate, methyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, lauryl acrylate, lauryl methacrylate, benzyl acrylate, benzyl methacrylate, acrylic acid Examples thereof include cyclohexyl and cyclohexyl methacrylate.

Further, the nitrile rubber (1) is obtained by copolymerizing a small amount of an unsaturated carboxylic acid compound such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, allyl glycidyl ether, or an aliphatic conjugated diene. It may be hydrogenated in part or in whole. Further, the nitrile rubber can contain a gel component insoluble in methyl ethyl ketone by copolymerizing a monomer having a plurality of double bonds in the molecule at the time of polymerization. Here, if the gel content is 30% by weight or more, preferably 50% by weight or more, the workability is remarkably improved. Mooney viscosity of these nitrile rubbers (ML _{1 + 4} , 100 ° C)
Is not particularly limited, but preferably 20 to
One of 150 is used. The above nitrile rubber is
Each of these may be used alone or in combination of two or more.

Next, the fluororubber (2) in the present invention
Is a copolymer or a copolymer of a fluorine-containing monomer and another monomer copolymerizable with the fluorine-containing monomer. As the fluorine-containing monomer, vinylidene fluoride, hexafluoropropene, pentafluoropropene, trifluoroethylene,
Trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoro (methyl vinyl ether), perfluoro (propyl vinylidene), etc. are used, and as a monomer copolymerizable with these,
Examples thereof include vinyl compounds such as acrylic acid esters, olefin compounds such as propylene or diene compounds, halogen-containing vinyl compounds containing chlorine, bromine and iodine.

Specific examples of the fluororubber (2) include vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and tetrafluoroethylene-propylene copolymer. Examples thereof include a combination and a tetrafluoroethylene-vinylidene fluoride-propylene terpolymer. These fluororubbers (2)
Can be classified into a type (2-a) that can be crosslinked by a combination of an organic peroxide and a crosslinking aid, and a type (2-b) that can be crosslinked with a polyol or an amine without being crosslinked with an organic peroxide. Specific examples of the fluororubber (2-a) include Aflas series (manufactured by Japan Synthetic Rubber Co., Ltd.), Viton GF (manufactured by DuPont, USA), Daier G902 (manufactured by Daikin Industries, Ltd.), Rubber (2-b)
Viton A, B, E60C (Dupont, USA), Technofron (Monte Edison, Italy)
And so on. The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the fluororubber (2) is not particularly limited,
It is preferably 30 to 150. The weight ratio of the nitrile rubber (1) and the fluororubber (2) in the rubber composition of the present invention is 5 to 70 parts by weight, preferably 10 to 50 parts by weight, the fluororubber (2).
95 to 30 parts by weight, preferably 90 to 50 parts by weight [wherein nitrile rubber (1) + fluorine rubber (2) = 100
If the amount of the fluororubber (2) is less than 30 parts by weight, the extrusion processability is remarkably deteriorated, and the compound is pulverized, while if it exceeds 95 parts by weight, the compression load resistance is deteriorated.

Next, in the present invention, as the crosslinking agent for the nitrile rubber (1) mixed with the nitrile rubber (1) and the fluororubber (2), for example, an organic peroxide,
Examples thereof include a sulfur-based vulcanizing agent, a resin vulcanizing agent, a quinoid-based vulcanizing agent, and a hydrogen siloxane-based vulcanizing agent. Nitrile rubber in the rubber composition of the present invention (1)
Examples of the combination of the fluororubber (2-a) and (2-b) with the diene rubber (1) include the following. Nitrile rubber (1) / fluorine rubber (2-a) / organic peroxide Nitrile rubber (1) / fluorine rubber (2-b) / organic peroxide Nitrile rubber (1) / fluorine rubber (2- a) / fluorine rubber (2-b) / organic peroxide nitrile rubber (1) / fluorine rubber (2-a) / sulfur vulcanizing agent nitrile rubber (1) / fluorine rubber (2-b) / Sulfur-based vulcanizing agent Nitrile rubber (1) / fluorine rubber (2-a) / quinoid vulcanizing agent Nitrile rubber (1) / fluorine rubber (2-b) Resin vulcanizing agent Nitrile rubber (1) / Fluorine rubber (2-a) / hydrogen siloxane vulcanizing agent Nitrile rubber (1) / fluorine rubber (2-b) / hydrogen siloxane vulcanizing agent

Examples of the organic peroxide as a cross-linking agent for the fluororubber (2-a) 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 benzoate,
1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, etc., preferably 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 Is. These organic peroxides may be used alone or in combination of 2
More than one species can be used in combination.

The amount of the organic peroxide which is a crosslinking agent for the nitrile rubber (1) is preferably 0.01 to 100 parts by weight with respect to 100 parts by weight of the nitrile rubber (1) and the fluororubber (2). It is 5 parts by weight, more preferably 0.05 to 2 parts by weight, and if it is less than 0.01 parts by weight, the nitrile rubber (1) is not sufficiently cross-linked and the processability of the rubber composition and the compression set of the vulcanized product are permanent. Strainability and resistance to compressive load are not sufficient, while if it exceeds 5 parts by weight, the workability tends to deteriorate, and the vulcanization physical properties such as mechanical strength and elongation of the resulting composition are inferior. As the cross-linking aid, functional unsaturated monomers such as allyl compounds, metal methacrylates, methacrylates and divinyl compounds, and further reactive unsaturated compounds such as functional polymers such as polybutadiene, oxime compounds and a wide range of sulfur compounds, etc. However, reactive unsaturated compounds are preferable from the standpoint of cross-linking property or kneading property during compounding, and in particular, compression set, heat resistance and the like, polyallyl compounds and A polyfunctional compound such as 1,2-polybutadiene can be preferably used.

As the polyallyl compound which can be preferably used in the present invention, an allyl group (—CH ₂ CH═CH ₂ ) is used.
Various compounds having more than one can be exemplified. For example, polyallyl-substituted alkyl or aromatic amines such as diallyl ether of glycerin, diallylamine and triallylamine, polyallyl-substituted phosphoric acid or phosphorous acid represented by triallyl phosphoric acid, diallyl succinate, diallyl adipate, etc. , Polyallyl substitution products of carboxylic acids such as diallyl phthalate, diallyl melamine, triallyl cyanurate, triallyl isocyanurate and the like. These may be used alone or in combination of two or more. A preferred specific example is 2 mmHg
Triallyl cyanurate (162 ° C / 2 mmHg) having a boiling point of 30 ° C or more under reduced pressure, triallyl phosphate (15
7 ° C./44 mmHg), triallyl isocyanurate, diallyl phthalate (161 ° C./4 mmHg), diallyl melamine and the like. The amount of the crosslinking aid added is 0.1 to 10 parts by weight, preferably 1 to 7 parts by weight, based on 100 parts by weight of the nitrile rubber (1) and the fluororubber (2).

In the present invention, as a method of adding a crosslinking agent to the nitrile rubber (1) and the fluororubber (2), the nitrile rubber (1), the fluororubber (2) and the crosslinking agent are simultaneously added and mixed. It is also possible to knead, or after mixing the nitrile rubber (1) and the fluororubber (2) in advance, a crosslinking agent can be added. Mixing is carried out with various extruders, Banbury mixers, kneaders, rolls, etc., although the temperature varies depending on the kind of the cross-linking agent, but the temperature at which the cross-linking agent usually reacts; ie, 50 to 250 ° C., preferably 100 to 2
00 ° C., time; 2 minutes to 1 hour, preferably 3 minutes to 45 minutes. Kneading can be carried out, and a preferable kneading method is a method using an internal mixer such as a Banbury mixer or a kneader. .. At this time, if the kneading temperature is less than 50 ° C. and crosslinking occurs, it is difficult to control the reaction, while if it exceeds 250 ° C., the rubber tends to deteriorate. Further, when the kneading time is shorter than 2 minutes, it is difficult to control the reaction, and it is difficult to obtain a uniform composition,
On the other hand, if it exceeds 1 hour, the kneading cost increases, which is not preferable.

The kneading temperature at the time of adding the crosslinking agent is usually 10 to 200 ° C., preferably 20 to 150 ° C.
Therefore, in the case of an organic peroxide, it is preferable that its half-life is 1 minute or less. As described above, the crosslinking in the present invention must be performed during mixing. That is, during mixing, a shearing force is applied to the elastomer, so that the dispersed particles of the nitrile rubber (1) or the fluororubber (2) are kept in a smaller state, and the entanglement of molecules at the interface is better. This is because many have occurred. In this case, if you stop applying the shearing force,
The disperse particles of the nitrile rubber (1) or the fluororubber (2) are associated with each other to increase the particle size and reduce the entanglement of molecules. Thus, by crosslinking the nitrile rubber (1) simultaneously with mixing, the system can be fixed in a good dispersion state.

The rubber composition of the present invention contains nitrile rubber (1) and fluororubber (2) as main components,
Other diene rubbers such as styrene-butadiene rubber (SBR) and isoprene rubber (IR) other than the above rubber components; ethylene-α-olefin- (diene) rubber [EP (D) M], butyl rubber, acrylic rubber Ordinary elastomers such as saturated rubber such as chlorosulfonated polyethylene can be added in an amount of about 10% by weight or less, and various compounding agents which are usually used can be added.
These compounding agents may be added in the process of producing the rubber composition of the present invention as needed, or may be added after the production of the composition. That is, as the reinforcing filler and extender, for example, 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, talc, mica powder, aluminum sulfate, calcium sulfate,
Barium sulfate, asbestos, glass fiber, organic reinforcing agent,
Mention may be made of organic fillers.

Examples of dispersion aids include higher fatty acids and metal amine salts thereof; examples of plasticizers include phthalic acid derivatives and adipic acid derivatives; examples of softeners include lubricating oils, process oils, coal tar, castor oil, and steer. Calcium phosphate; Antiaging agents such as phenylenediamines, phosphates, quinolines, cresols, phenols, dithiocarbamate metal salts; Heat resistance agents such as iron oxide, cerium oxide, potassium hydroxide, iron naphthenate, Potassium naphthenate; In addition, colorants, ultraviolet absorbers, flame retardants, oil resistance improvers, foaming agents, scorch inhibitors, tackifiers, lubricants and the like can be optionally mixed. These compounded rubber compositions (fluororubber compositions) can be added to a crosslinking agent for the fluororubber (2), for example, the above-mentioned organic peroxide and a crosslinking aid, and a polyol by a conventional kneading machine such as a roll or a Banbury mixer. After adding a vulcanizing agent, a vulcanization accelerator for polyol vulcanization, and an amine vulcanizing agent, and kneading to make a vulcanizable fluororubber composition, molding and vulcanization are performed under ordinary vulcanized rubber production conditions, and fluororubber crosslinking is carried out. Can be a product.

As the polyol vulcanizing agent as a crosslinking agent for the fluororubber (2-b), polyhydroxy aromatic compounds such as hydroquinone, bisphenol A, bisphenol AF and salts thereof are preferably used. Further, a fluorine-containing aliphatic diol can also be used. The addition amount of these polyol vulcanizing agents is usually about 0.1 to 20 parts by weight, preferably about 1 to 10 parts by weight, per 100 parts by weight of the fluororubber composition. Examples of the polyol vulcanization accelerator used in combination with the polyol vulcanizing agent include quaternary ammonium compounds such as methyltrioctylammonium chloride, benzyltriethylammonium chloride and tetrahexylammonium tetrafluoroborate; 8-methyl-1,8-diazacyclo ( 5,4,0) -7-Undecenyl chloride, such as 4
Quaternary phosphonium compounds such as benzyltriphenylphosphonium chloride, m-trifluoromethylbenzyltrioctylphosphonium chloride, and benzyltrioctylphosphonium bromide are preferred. The amount of the vulcanization accelerator added is usually about 0.2 to 10 parts by weight per 100 parts by weight of the fluororubber composition.

Further, as the amine vulcanizing agent for the fluororubber (2-b), various alkylamines such as hexamethylenediamine, tetraethylenepentamine and toluethylenetetramine, and various aromatic compounds such as aniline, pyridine and diaminobenzene. Amines and salts of fatty acids such as carbamic acid and cinnamylidenic acid of these amines can be used. The amount of the amine vulcanizing agent added is
It is usually 0.1 to 100 parts by weight of the fluororubber composition.
It is about 10 parts by weight, preferably about 0.5 to 5 parts by weight.
To vulcanize the vulcanizable fluororubber composition, it is usually at a temperature of 80 to 200 ° C. for a few minutes to 3 hours and 20 to 200K.
Primary vulcanization under pressure of g / cm ² , and if necessary 8
Secondary vulcanization is performed at 0 to 200 ° C. for 1 to 48 hours to obtain a fluororubber crosslinked product. As described above, the fluororubber composition of the present invention has a Banbury mixer, a kneader, and
It can be kneaded uniformly with a kneading machine such as a two-roll mill. In addition, when adding vulcanizing agents, vulcanization accelerators, etc. by means of rolls, if a mixture with diene rubber (including those containing additives such as fillers) is used, it takes a lot of time to wind the rolls. However, the rubber composition of the present invention can be instantly wound by a roll, and the workability is remarkably improved. Further, the fluorinated rubber cross-linked product (rubber elastic body) obtained by vulcanizing the vulcanizable rubber composition of the present invention has excellent heat resistance, weather resistance, compression set, and compression load resistance. It can be used in industrial, electrical and chemical fields.

Next, the present invention will be described in detail based on examples. Example 1 As a nitrile rubber, Reference Example 1 TECHNOFLON TN80 was used as a fluororubber, and the weight ratio of these was 35:65, and stearic acid was added as a processing aid to a rubber mixer (set temperature 100 ° C.), When it becomes homogeneous, quaternary phosphonium salt, 1,3-bis (t
-Butyl peroxy-isopropyl) benzene, N, N '
After n-phenylene cymaleimide was added and kneaded, and the mixture became uniform again, the temperature was raised to 170 to 180 ° C., and the kneading torque and the rubber temperature became almost constant (after about 10 to 20 minutes). ) Emitted. Next, the compounded rubber thus obtained was wound around a two-roll again, and
The compound obtained by adding other compounding chemicals such as the crosslinking agent and the crosslinking aid shown in 1 above and kneading the mixture was press-vulcanized (100 to 150 kg / cm ² , 170 ° C. × 3) using a bellows-shaped mold.
It was heated and pressurized for 0 minutes) to obtain a rubber hose. The formulations of the examples and the test results are shown in Table 1.

[0022]

[Table 1]

Example 2 A rubber hose was obtained in the same manner as in Example 1 except that Reference Example 2 was used as the nitrile rubber and Technoflon P2 was used as the fluororubber, and the weight ratio of these was 35:65. (Example 3) A rubber hose was obtained in the same manner as in Example 1 except that Reference Example 2 was used as the nitrile rubber and Technoflon TH340 was used as the fluororubber, and the weight ratio of these was 50:50. (Example 4) A rubber hose was obtained in the same manner as in Example 1 except that Reference Example 3 was used as the nitrile rubber and Technoflon TN80 was used as the fluororubber, and the weight ratio of these was 35:65. Acrylonitrile content% Methyl ethyl ketone insoluble gel content% Reference Example 1 26 50 Reference Example 2 26 80 Reference Example 3 48 90 Here, the gel content is 1 g of a sample dissolved in 100 cc methyl ethyl ketone, filtered through a 200 mesh wire mesh, and at 105 ° C. It is the measured value of the insoluble matter dried for 4 hours.

(Comparative Example 1) JSR as nitrile rubber
A vulcanized rubber hose was obtained in the same manner as in Example 1 except that N240S (gel content of 10% or less) was used, and TECHNOFLON TN80 was used as the fluororubber, and the weight ratio of these was 35:65. Table 1 shows the composition of the comparative example and the test results. (Comparative Example 2) JSRN215SL as a nitrile rubber
(Gel content of 10% or less) and TECHNOFLON TH340 as fluororubber, and these are used in a weight ratio of 50:
As 50, a vulcanized rubber hose was obtained in the same manner as in Example 1. Comparative Example 3 Using Reference Example 3 as the nitrile rubber,
A vulcanized rubber hose was obtained in the same manner as in Example 1, except that TECHNOFLON TN80 was used as the fluororubber and the weight ratio of these was 20:80. (Comparative Example 4) Using Reference Example 3 as the nitrile rubber,
A vulcanized rubber hose was prepared in the same manner as in Example 1 except that TECHNOFLON TN80 was used as the fluororubber, and a weight ratio of these was 35:65, and that no crosslinking agent was added for the purpose of crosslinking the nitrile rubber during kneading. Obtained. Example,
The processability of the rubber hose shown in the comparative example was evaluated by the Gerbe die extrusion test. The conditions of the Gerbedee extrusion test are as follows. Cylinder diameter 50mm Cylinder length 700m
m Hopper temperature 60 ° C Barrel temperature 75 ° C Head temperature 95 ° C Screw rotation speed 10r
pm

[0025]

EFFECTS OF THE INVENTION The rubber composition of the present invention is excellent in processability as compared with a nitrile rubber which does not contain a gel component dispersed in a fluorine rubber in the form of particles. Because of its excellent properties, it can be applied to a wide range of solvent-based hose applications.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location C08L 27:12 (72) Inventor Ken Akiyama 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Formed Rubber Co., Ltd.

Claims (1)

[Claims] 1. A gel component 30 insoluble in methyl ethyl ketone.
Fluorine obtained by blending 5 to 70 parts by weight of nitrile rubber (1) containing 95% by weight or more and 95 to 30 parts by weight of fluororubber (2) with the crosslinking agent of (1) and reacting while giving shear deformation. Rubber composition.