JPH11116811A - Vulcanizable rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having excellent strength and water resistance and improved mold staining properties and heat aging characteristics, by including a silicone rubber and a specific ethylene/α-olefin/polyene amorphous copolymer. SOLUTION: This composition (A) 2-98 wt.% of a silicone rubber and (B) 98-2 wt.% of an ethylene/α-olefin/polyene amorphous copolymer. The polyene is at least one kind of a terminal vinyl group-containing norbornene compound of formula I ((n) is 0-10; R<1> is H or a 1-10C alkyl; R<2> is H or a 1-5C alkyl) or formula II (R<3> is H or a 1-10C alkyl). The copolymer B is preferably an ethylene/propylene/5-methylene-2-norbornene random copolymer or an ethylene/ propylene/5-vinyl-2-norbornene random copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vulcanizable rubber composition,
More specifically, the present invention relates to a vulcanizable rubber composition containing a silicone rubber and an ethylene / α-olefin / polyene amorphous copolymer having a specific polyene component. The present invention relates to a vulcanizable rubber composition having excellent mold resistance and heat aging resistance as compared with an ethylene / α-olefin / polyene amorphous copolymer.

[0002]

2. Description of the Related Art Silicone rubber is used in the fields of packing, gaskets, diaphragms, rolls, belts, etc. because of its good heat aging resistance, but further improvement in strength and water resistance is required. ing. Attempts have been made to incorporate ultrafine silica as one of the improved formulations, whereby the strength is improved, but the processability tends to be impaired.

On the other hand, an amorphous ethylene / α-olefin / polyene copolymer has advantages such as high strength, excellent water resistance and excellent electrical insulation. Radiator
Used in tar hoses, boots, plug caps and the like. However, further improvement of heat aging resistance or solution of mold contamination is required.

[0004]

Accordingly, a first object of the present invention is to provide a vulcanizable rubber composition having excellent strength and water resistance as compared with silicone rubber. A second object is to provide a vulcanizable rubber composition having excellent heat aging resistance as compared with an ethylene / α-olefin / polyene amorphous copolymer and having improved mold contamination. is there.

[0005]

According to the present invention, a vulcanizable rubber composition comprises 2 to 98% by weight of a silicone rubber (A) and an ethylene / α-olefin / polyene amorphous copolymer. (B) is 98 to 2% by weight, and the polyene is at least one kind of norbornene compound having a terminal vinyl group represented by the following general formula [I] or [II]:

Embedded image Here, n is an integer of 0 to 10, R ¹ is hydrogen or an alkyl group having 1 to 10 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 5 carbon atoms,

[0006]

Embedded image Here, R ³ is hydrogen or an alkyl group having 1 to 10 carbon atoms.

The silicone rubber used is preferably a silicone containing a vinyl group, and the composition can be easily vulcanized with an organic peroxide.

[Detailed Description of the Invention] Next, the present invention will be specifically described. [Silicon Rubber (A)] The silicone rubber (A) used in the present invention is a rubber having an organosiloxane unit as a repeating unit in a polymer main chain. Here, the organosiloxane unit is represented by the following general formula [IV]. — {Si (R ⁴ ) (R ⁵ ) —O—} [IV] Here, each of R ⁴ and R ⁵ is a monovalent organo group, particularly a methyl group or an ethyl group. Alkyl group, an aryl group such as a phenyl group, an alkenyl group such as a vinyl group, γ-
A cyanoalkyl group such as a cyanopropyl group; a fluoroalkyl group such as a trifluoropropyl group;

The rubber having an organosiloxane unit is known per se, such as dimethyl silicone rubber, methyl phenyl silicone rubber, methyl vinyl silicone rubber, fluorinated alkyl methyl silicone rubber, cyanoalkyl silicone rubber, etc. Is usually called by the name of

[0010] Among these silicone rubbers, dimethyl silicone rubber is the most general-purpose one, while methyl phenyl silicone rubber has improved low-temperature characteristics, better heat resistance and radiation resistance than dimethyl silicone rubber. It is known that there is. Methyl vinyl silicone rubber has a double bond introduced into the polymer molecule in order to increase the vulcanization rate, and has a characteristic that the compression strain after vulcanization is small. Furthermore, alkyl fluoride
Methyl silicone rubber has excellent solvent resistance, and cyanoalkyl silicone rubber has improved solvent resistance and cold resistance.

As described above, the silicone rubbers each have characteristic physical properties, and are selected from the above according to various uses. In the present invention, it is particularly preferable that R ⁴ and / or R ⁵ in the organosiloxane unit is a vinyl group, and the vinyl group content as a crosslinking site is 0.02 to 2.0, preferably 0.05 to 2.0. 1.5 mol% is advantageously used. When the vinyl group content is within this range, mold contamination is improved, and the heat aging resistance of the vulcanized rubber is improved.

Also, silicone rubber (raw rubber) before cross-linking
Is subjected to gel permeation chromatography (GP
C) was measured in a chloroform solvent at 25 ° C., and the weight average molecular weight in terms of standard polystyrene was 100 × 1.
It is preferably from 0 ^{3 to} 2 × 10 ⁶ . When such a silicone rubber is used, a vulcanizable rubber composition having excellent mechanical strength, mold stain resistance, and heat aging resistance can be obtained.

[0013] The silicone rubber is synthesized by a method known per se. For example, an organochlorosilane represented by the following general formula [V] is hydrolyzed to produce a cyclic diorganosiloxane oligomer represented by the general formula [VI], particularly a tetramer, and then this ring oligomer is subjected to ring-opening polymerization. By this, it is manufactured. ^{(R 4) (R 5)} Si · Cl 2 ······· [V] {(R 4) (R 5) Si-O} n ······ [VI] wherein, R ⁴ And R ⁵ are the same as described above, and n is a number from 3 to 25.

In the ring-opening polymerization, a strong alkali or a strong acid is used as a catalyst. More specifically, caustic potash,
Examples include quaternary ammonium compounds such as tetramethylammonium hydroxide, and quaternary phosphates such as tetra-n-butylphosphonium hydroxide. The reaction is usually performed in a bulk state, and the reaction is stopped by adding hexamethyldisiloxane or sodium hydroxide.

A method for introducing an organo group other than a methyl group into the side chain R ⁴ and / or R ⁵ of the organosiloxane unit is to use an organochlorosilane having a desired organo group as a raw material and to prepare a cyclic diorganosiloxane oligomer. May be produced and subjected to ring-opening polymerization, or a method of partially modifying the silicone rubber by adding an alkoxysilane having a corresponding organo group to the reaction system during ring-opening polymerization.

[Ethylene / α-olefin / polyene amorphous copolymer (B)]
The olefin / polyene amorphous copolymer (B) is an amorphous copolymer containing, as constituent units, ethylene, α-olefin, and the above-mentioned norbornene compound having at least one terminal vinyl group. .

The α-olefin has 3 carbon atoms.
~ 20 α-olefins. Specifically, propylene, butene-1,4-methylpentene-1, hexene-
1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene
1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, nonadecene-1, eicosene-1, 9-methyl-decene-1, 11-methyl-dodecene-1, 12-ethyl-tetradecene-1, and the like Is mentioned. These α-olefins may be used alone or
Among them, α-olefins having 3 to 10 carbon atoms are preferable, and propylene, butene-1, hexene-1, and octene-1 are particularly preferable.

Here, the ratio of ethylene to α-olefin is expressed by an ethylene / α-olefin ratio of 40 /
60-95 / 5, preferably 50 / 50-90 / 1
0, more preferably 55/45 to 85/15, particularly preferably 60/40 to 80/20 (molar ratio). When the composition ratio of ethylene and α-olefin is within the above range, physical properties such as processability, rubber-like properties, and weather resistance can be maintained at a satisfactory level.

Polyene is a norbornene compound having at least one terminal double bond represented by the following formula [I] or [II].

Embedded image

Embedded image In the above formula, n is an integer of 0 to 10, and R ¹ , R ² ,
R ³ will be described below.

R ¹ in the above formula [I] and R ³ in the above formula [II] each represent a hydrogen atom or a carbon atom having 1 carbon atom.
10 to 10 alkyl groups. Here, as the alkyl group, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-pentyl group, isopentyl group, t-pentyl group,
Neopentyl group, hexyl group, octyl group, nonyl group,
A decyl group is exemplified.

R ² in the general formula [I] is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples thereof include a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a t-pentyl group, and a neopentyl group.

Examples of the norbornene compound represented by the above general formula [I] or [II] include 5-methylene-2
-Norbornene, 5-vinyl-2-norbornene, 5-
(2-propenyl) -2-norbornene, 5- (3-butenyl) -2-norbornene, 5- (1-methyl-2-
Propenyl) -2-norbornene, 5- (4-pentenyl) -2-norbornene, 5- (1-methyl-3-butenyl) -2-norbornene, 5- (5-hexenyl)-
2-norbornene, 5- (1-methyl-4-pentenyl) -2-norbornene, 5- (2,3-dimethyl-3)
-Butenyl) -2-norbornene, 5- (2-ethyl-
3-butenyl) -2-norbornene,

5- (6-heptenyl) -2-norbornene, 5- (3-methyl-5-hexenyl) -2-norbornene, 5- (3,4-dimethyl-4-pentenyl)-
2-norbornene, 5- (3-ethyl-4-pentenyl) -2-norbornene, 5- (7-octenyl) -2
-Norbornene, 5- (2-methyl-6-heptenyl)
-2-norbornene, 5- (1,2-dimethyl-5-hexenyl) -2-norbornene, 5- (5-ethyl-5
-Hexenyl) -2-norbornene, 5- (1,2,3
-Trimethyl-4-pentenyl) -2-norbornene and the like.

Among them, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, 5- (2-propenyl) -2-norbornene, 5- (3-butenyl)-
2-norbornene, 5- (4-pentenyl) -2-norbornene, 5- (5-hexenyl) -2-norbornene, 5- (6-heptenyl) -2-norbornene, 5-
The use of (7-octenyl) -2-norbornene is preferred.

In the molecule of the copolymer (B), in addition to the norbornene compound described above, the following non-conjugated polyenes may be mixed and used as long as the desired physical properties are not impaired. a) 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl-1,
Linear non-conjugated dienes such as 4-hexadiene and 7-methyl-1,6-octadiene;

B) Methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene,
-Vinylidene-2-norbornene, 6-chloromethyl-
Cyclic non-conjugated dienes such as 5-isopropenyl-2-norbornene, dicyclopentadiene, c) 2,3-diisopropylidene-5-norbornene;
Trienes such as 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene.

Among these ethylene / α-olefin / polyene amorphous copolymers (B), ethylene / propylene / 5-methylene-2-norbornene random copolymer or ethylene / propylene / 5-vinyl-2-vinyl It is preferable to use a norbornene random copolymer in order to obtain a vulcanizable rubber composition.

These polyene components may be used alone or in combination.
It can be used in combination of more than one kind. The content of the polyene component in the copolymer (B) can be indirectly estimated from the content of the unsaturated bond indicated by the iodine value by measuring the iodine value of the copolymer. . The iodine value of the copolymer used in the present invention is 0.1.
5 to 50, preferably 0.8 to 40, more preferably 1 to 30, particularly preferably 1.5 to 20 (g / 100
g). Within this range, the preferred polyene component is used because the rubber has the necessary mechanical strength, the elongation and the permanent deformation are in an appropriate range, and the resistance to environmental degradation is large. Is the content of

When the molecular weight of the copolymer (B) is represented by the intrinsic viscosity [η] measured in a decalin solution at 135 ° C., it is 0.1%.
It is in the range of 5 to 10, preferably 0.7 to 2.0 (dl / g). When the intrinsic viscosity [η] is within the above range, the copolymer has high mechanical strength and excellent processability.

On the other hand, the ratio (Mw / M) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC)
n) is usually an index of the molecular weight distribution, but the Mw / Mn value of the copolymer (B) used in the present invention is 3 to 5
0, preferably 3.3 to 40, more preferably 3.5 to 30. When the index of the molecular weight distribution is within the above range, the copolymer is excellent in balance between physical properties and processability as a rubber.

This ethylene / α-olefin / polyene
Amorphous copolymers are crosslinked by organic peroxides,
High crosslink density. The degree of crosslink density is effective mesh chain density
Degree is determined by the degree (ν).
Mixing 0.01 mole of Milper oxide at 170 ° C
When press-crosslinking under the conditions of 10 minutes, the effective mesh chain at that time
The density (ν) is 1.5 × 10²⁰~ 100 × 10²⁰,
Preferably 1.8 × 10²⁰~ 100 × 10²⁰, Even better
Preferably 2.0 × 10²⁰~ 100 × 10²⁰ Pieces / cm^Threeso
is there.

The ethylene / α-olefin / polyene amorphous copolymer according to the present invention using 5-methylene-2-norbornene (MND) or 5-vinyl-2-norbornene (VND) which is a cyclic non-conjugated polyene. When the polymer (B) is peroxide-crosslinked, a rubber having an effective network chain density (ν) in the above-mentioned range can be produced, and this rubber has a small permanent set and a remarkably excellent heat aging resistance. .

On the other hand, in the conventional ethylene / α-olefin / polyene amorphous copolymer containing 5-ethylidene-2-norbornene (ENB) and dicyclopentadiene (DCPD), even if the copolymer Even if the iodine value is within the above-mentioned range, it is difficult to make the effective network chain density (ν) after cross-linking into the above-mentioned range, and such a copolymer has a large permanent set and a sufficient heat aging resistance. is not. This means that even if the iodine value is the same, that is, the content of unsaturated bond in the copolymer is the same, the copolymer containing the norbornene compound represented by the general formula [I] or [II] as a polyene component. Combination (B) is ENB or D
This means that the rate of crosslinking by the peroxide is higher than that of the copolymer containing CPD.

The reason is considered as follows. That is, when a non-conjugated polyene is copolymerized with ethylene and an α-olefin, one ethylenically unsaturated bond is used in the copolymerization reaction and the other ethylenically unsaturated bond remains in the copolymer chain. When the non-conjugated polyene has a cyclic structure, there are two types of residual ethylenically unsaturated bonds, one in the ring and the other in the outside of the ring. This is considered to have a higher degree of freedom and a higher reactivity than the ethylenically unsaturated bond in the ring. When a norbornene compound having the chemical structure represented by the general formula [I] or [II] is used, a high proportion of the ethylenically unsaturated bond remaining outside the ring is high, and this is used for a crosslinking reaction. It is presumed to have given the crosslinked rubber physical properties.

Further, in the ethylene / α-olefin / polyene amorphous copolymer (B) according to the present invention, there is a close relationship between the crosslink density and the melt fluidity. That is,
The shear rate γ ₁ when the shear stress is 0.4 × 10 ⁶ dyn / cm ² and the shear stress 2.4 × 10 ⁶ dyn / cm ² are determined from the melt flow curve at 100 ° C. The relationship between the logarithmic value of the ratio (γ ₂ / γ ₁ ) to the shear rate γ _{2 at the} time shown and the effective mesh chain density (ν) is represented by the following relational expression [III]:
It is desirable to satisfy 0.04 × 10 ⁻¹⁹ ≦ log (γ ₂ / γ ₁ ) /ν≦0.20×10 ⁻¹⁹ [III] Preferably, this relational expression is: 042 × 10 ⁻¹⁹ ≦ log (γ ₂ / γ ₁ ) /ν≦0.19×10 ^−19, More preferably, 0.050 × 10 ⁻¹⁹ ≦ log (γ ₂ / γ ₁ ) /ν≦0.18 × 10 ^-19 .

The relational expression [III] shows the balance between the shear stress dependence of the shear rate during the melt flow of rubber and the crosslinkability. The melt viscosity η is expressed as η = σ / γ when the shear rate is γ and the shear stress is σ. In the melt flow curve plotting the relationship between the shear stress σ of the polymer and the shear rate γ, The degree of increase in the shear rate γ per degree of increase in the shear stress σ is extremely large. Formula [III]
The logarithmic value of the shear rate ratio (γ ₂ / γ ₁ ) of the polymer is larger when the shear stress σ dependence of the shear rate γ during the melt flow of the copolymer is larger, and is smaller when the copolymer is smaller. is there. Therefore, when the ratio between the logarithmic value of (γ ₂ / γ ₁ ) and the effective network chain density (ν) is within the range of the formula [III], the processability and mechanical properties of the copolymer are at a high level. It is desirable to obtain excellent heat aging resistance while maintaining the heat aging resistance. That is, if this value falls below 0.04 × 10 ^-19 ,
Workability tends to decrease, while 0.20 × 10 ^-19
If it exceeds, the strength decreases, the permanent set increases,
The heat aging resistance tends to decrease, and it is not preferable to use a copolymer having such physical properties in the composition of the present invention.

[Production Method of Copolymer (B)] In the present invention, the ethylene / α-olefin / polyene amorphous copolymer will be described below with reference to ethylene, α-olefin and polyene having a norbornene skeleton. It is obtained by random copolymerization under polymerization conditions.

The copolymerization reaction is usually carried out by a continuous polymerization method, in which the raw material monomer, catalyst component and hydrocarbon medium are continuously supplied to the polymerization reaction system, and the polymerization reaction mixture is continuously discharged from the polymerization reaction system. Is done. The monomer composition is represented by a ratio of ethylene / α-olefin in the copolymer, which is 40/60 to 95/5 (molar ratio), and a polyene / ethylene ratio of 0.01 to 0.2 (molar ratio). Molar ratio)
Under the conditions of a polymerization temperature of 30 to 60, especially 30 to 50 ° C. and a polymerization pressure of 4 to 12, especially 5 to 8 kgf / cm ² , and if necessary, an inert gas such as nitrogen or argon. May be. The average residence time varies depending on the type of the polymerization raw material, the concentration of the catalyst component and the temperature, but is usually in the range of 5 minutes to 5 hours, preferably 10 minutes to 3 hours. Further, in order to adjust the molecular weight of the copolymer, a molecular weight modifier such as hydrogen may be appropriately present.

The main components constituting the polymerization catalyst are a vanadium compound and an organoaluminum compound which are soluble in a hydrocarbon medium of the polymerization reaction system. If necessary, a third component such as an electron donor can be present together.

As a soluble vanadium compound catalyst component
Can be used a compound represented by the following general formula. VO
(OR)_n X_3-n, Or V X_Four Where R is carbonized
A hydrogen group, X is a halogen atom, 0 ≦ n ≦ 3
Vanadium compound represented by the following general formula, or
These electron donor adducts can be mentioned as typical examples.
Wear. VO (OR) a Xb or V (OR) c Xd
Here, 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ a + b ≦ 3, 0 ≦
c ≦ 4, 0 ≦ d ≦ 4, 3 ≦ c + d ≦ 4

More specifically, VOCl ₃ , VO (OC
_{2 H 5) Cl 2, VO} (OC 2 H 5) 2 Cl, VO (O
-Iso-C ₃ H ₇ ) Cl ₂ , VO (On-C ₄ H)
_{9) Cl 2, VO (OC} 2 H 5) 3, VOBr 3, VC
_{l 4, VO (O-n} -C 4 H 9) 3 , etc. can be exemplified.

As the organoaluminum compound catalyst component, a compound represented by the following general formula can be used. R _m Al X _3-m where R is a hydrocarbon group, X is a halogen atom, 0 <m
≦ 3

Specific examples of the aluminum compound represented by the above general formula include the following compounds. a) Trialkylaluminum such as triethylaluminum and triisobutylaluminum; b) Dialkylaluminum halide such as diethylaluminum chloride and diisobutylaluminum chloride; c) Like ethylaluminum sesquichloride, isobutylaluminum sesquichloride and n-hexylaluminum sesquichloride D) alkyl aluminum dihalides such as ethyl aluminum dichloride, ethyl aluminum dibromide, isobutyl aluminum dibromide;

Among these, it is preferable to use a halogen-containing organoaluminum compound whose average composition satisfies 1 ≦ m ≦ 2 in the general formula. In addition, together with or instead of the organoaluminum compound represented by the general formula, R
An organoaluminum compound having a part of which is substituted with hydrogen, an alkoxy group, or the like can also be used. Among the organoaluminum compounds, (C ₂ H ₅ ) ₂ AlCl and (C ₂
The use of a mixture obtained by mixing H ₅ ) _1.5 AlCl _1.5 at a ratio of _{1/5 to} 10/1, preferably 1/2 to 8/1 (molar ratio) is effective in reducing the xylene insoluble content in the resulting copolymer. Desirable because it reduces production.

This copolymerization reaction can be carried out in a hydrocarbon medium, such as hexane,
Aliphatic hydrocarbons such as heptane, octane, kerosene, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, and polymerizable unsaturated hydrocarbons such as propylene Can also be exemplified. Even a mixed medium of two or more kinds may be used.

When the polymerization operation is carried out by a continuous method, the concentration of the soluble vanadium compound in the copolymerization reaction system is usually 0.01 to 5, preferably 0.0 to 5 as vanadium atoms.
5 to 3 (gram atoms / liter), and the concentration of the soluble vanadium compound supplied to the polymerization reaction system is 1 to 10 of the concentration of the soluble vanadium compound in the polymerization reaction system.
It is preferably in the range of 1 to 7, more preferably 1 to 5, and most preferably 1 to 3 times.

The ratio of aluminum atoms to vanadium atoms (Al / V) in the polymerization reaction system is 2 or more, preferably 2 to 50, particularly preferably 3 to 20. The soluble vanadium compound and the organoaluminum compound are each usually supplied after being diluted with the hydrocarbon medium. Here, it is desirable to dilute the soluble vanadium compound to the above concentration range, but a method is adopted in which the organoaluminum compound is adjusted to an arbitrary concentration of, for example, 50 times or less the concentration in the polymerization reaction system and supplied to the polymerization reaction system. You.

The produced copolymer solution discharged from the polymerization reaction system is a solution of the copolymer in a hydrocarbon medium, and the concentration of the copolymer contained in the solution is usually 2.0 to 2%.
0.0, preferably in the range of 2.0 to 10.0% by weight. The copolymer used in the present invention is obtained by removing the hydrocarbon medium from the polymer solution in a conventional manner.

[Organic peroxide] The vulcanizable rubber composition according to the present invention comprises a radical generator, in particular, an organic peroxide, comprising a silicone rubber (A) and an ethylene / α-olefin /
By further blending with the composition with the polyene amorphous copolymer (B) and heating, the crosslinking reaction proceeds, and a vulcanized rubber can be produced. The organic peroxide that can be used is not particularly limited, but preferred specific examples include the following compounds, and a mixture thereof.

A) Dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,
3,5-trimethylcyclohexane, t-butylcumyl peroxide, di-t-amyl peroxide, t-
Butyl hydroperoxide, 2,5-dimethyl-2,
5-di (benzoylperoxy) hexane, α, α'-
Dialkyl peroxides such as bis (t-butylperoxy-m-isopropyl) benzene;

B) t-butyl peroxyacetate, t
-Butylperoxyisobutyrate, t-butylperoxypivalate, t-butylperoxymaleate, t
-Butyl peroxy neodecanoate, t-butyl peroxybenzoate, di-t-butyl peroxyphthalate, 1,1-bis-t-butyl peroxy-3,3
Peroxyesters such as 5-trimethylcyclohexane; c) Ketone peroxides such as dicyclohexanone peroxide.

Among these organic peroxides, a half-life of 1
Organic peroxides having a temperature of 130 to 200 ° C. are preferred because they are suitable for the actual vulcanization conditions, and in particular, dicumyl peroxide, di-t-butyl peroxide and di-peroxide. t-butylperoxy-3,3
5-trimethylcyclohexane, t-butylcumyl peroxide, di-t-amyl peroxide, t-butyl hydroperoxide, 1,1-bis-t-butylperoxy-3,3,5-tri-methylcyclohexane and the like Is preferably used.

[Gum Composition] The vulcanizable rubber composition of the present invention comprises a silicone rubber (A), ethylene
α-olefin / polyene amorphous copolymer (B), and the mixing ratio of both is expressed in terms of A / B weight% ratio and used in the range of 98/2 to 2/98. egoism,
Preferably 97/3 to 3/97, more preferably 95/5
It is good to use in the range of 〜5 / 95. Thus, the silicone rubber (A) and the ethylene / α-olefin / polyene amorphous copolymer (B) are mixed in a wide range to obtain a vulcanizable rubber composition having excellent rubber properties. .
Within this range, silicone rubber and ethylene
While maintaining the properties of the α-olefin / polyene amorphous copolymer, rubber with improved mechanical strength, water resistance, mold contamination resistance, heat aging resistance, and excellent cost performance is obtained. Can be

The amount of the organic peroxide used in the vulcanization step is based on 100 g of the silicone rubber (A) and the ethylene / α-olefin / polyene copolymer (B) in total.
1 × 10 ^{−3 to} 5 × 10 ⁻² mol, preferably 3 × 10 ⁻³ to
Adjustment to the range of 3 × 10 ^-2 mol is desirable because a desired vulcanization density can be obtained at an appropriate vulcanization speed.

The vulcanizable rubber composition of the present invention contains the above 3
In addition to the components, known additives such as reinforcing materials, fillers, softeners, vulcanization aids, processing aids, pigments, antioxidants, and other materials commonly used in rubber production are appropriately compounded. And vulcanized rubber is produced.

As the reinforcing material, for example, SRF, GPF,
Various carbon blacks such as FEF, MAF, ISAF, SAF, FT, and MT, and finely divided silica are appropriately used. As the filler, for example, light calcium carbonate, heavy calcium carbonate, talc, clay and the like are used. The amounts of these reinforcing materials and fillers are arbitrarily adjusted depending on the desired product, but all of them are 100 parts by weight in total of the silicone rubber (A) and the ethylene / α-olefin / polyene copolymer (B). The amount is usually 200 parts by weight or less, preferably 150 parts by weight or less.

As the softening material, a softening material usually used for rubber is used, for example, a process oil, a lubricating oil,
Petroleum-based substances such as paraffin, liquid paraffin, petroleum asphalt and petrolatum, chol tars such as coltar, coltar pitch, castor oil, rapeseed oil, fatty oils such as soybean oil and coconut oil , Wax oils, beeswax, carnauba wax, waxes such as lanolin, ricinoleic acid, palmitic acid, stearic acid, barium stearate, fatty acids such as calcium stearate, or a metal salt thereof, naphthenic acid or a metal soap thereof, Pine oil, rosin or derivatives thereof,

Ester plasticizers such as terpene resin, petroleum resin, cumarone indene resin, atactic polypropylene, dioctyl phthalate, dioctyl adipate, dioctyl sebacate, and carbonic acid such as diisododecyl carbonate. Examples include ester plasticizers, other microcrystalline waxes, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, and hydrocarbon-based synthetic lubricating oils. The amounts of these softeners are silicone rubber (A), ethylene α
-Usually 100 parts by weight or less, preferably 70 parts by weight, based on 100 parts by weight of the olefin / polyene copolymer (B).
Used in amounts up to parts by weight.

When an organic peroxide is used, it is preferable to use a vulcanization aid in combination. Examples of the vulcanization aid include sulfur, quinone dioximes such as P-quinone dioxime, and ethylene glycol.
Examples include acrylics such as rudimethacrylate and trimethylolpropane trimethacrylate, allyls such as diallyl phthalate and triallyl isocyanurate, and other maleimides and divinylbenzene. Such a vulcanization aid is preferably used in an amount of 0.5 to 2 mol, and more preferably equivalent to 1 mol of the organic peroxide used.

Processing aids include higher fatty acids, salts and esters thereof, such as ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, calcium stearate, zinc stearate, and esters of the above acids. And the like. Usually, these processing aids are used in combination with silicone rubber (A) and ethylene / α-olefin / non-conjugated polyene copolymer (B).
Up to about 10 parts by weight, preferably from about 1 to 5 parts by weight
Used by weight.

Further, depending on the product, a pigment is used. As the pigment, for example, an inorganic pigment such as titanium white and an organic pigment such as naphthol green B are used. The amount used varies depending on the product, but the maximum is 20 parts by weight, preferably 10 parts by weight, based on 100 parts by weight of the silicone rubber (A) and the ethylene / α-olefin / polyene copolymer (B). Used in quantity.

Other active agents include zinc white, polyethylene glycol, silane coupling agents, and organic titanates.
An ordinary rubber compounding agent such as (g) is appropriately compounded. The mixing of the compounding agent with the unvulcanized rubber can be performed using a Banbury mixer or a kneader.
, A silicone rubber (A), an ethylene / α-olefin / polyene copolymer (B), a filler, a softener and other compounding agents are supplied to a mixer such as
At a temperature of 3 to 10 minutes. After that,
The organic peroxide (C) is additionally mixed using a roll such as a roll, and the mixture is kneaded at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes to form a ribbon or sheet compound rubber. Take out as.

The compounded rubber thus prepared is molded into a desired shape using an extruder, an injection molding machine, a calendar roll, a press, or the like, and then in the molding machine or in a molding machine. The material is transferred into a vulcanization tank,
By heating at a temperature of 0 ° C. for 1 to 30 minutes, a vulcanized product can be obtained. This step of vulcanization may be performed using a mold, or may be performed without using a mold.

[0064]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto. (Method of Measuring Physical Property Values) Copolymer composition: ¹³ C-NMR was used. Iodine value: titration method Intrinsic viscosity [η]: Measured in decalin at 135 ° C.

Molecular weight distribution: The ratio (Mw / Mn) was calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) determined by GPC. For GPC, GMH-HT and GMH-HTL manufactured by Tosoh Corporation were used for the column, and orthodichlorobenzene was used for the solvent.

[Γ ₂ / γ ₁ ]: The melt flow curve at 100 ° C. was determined, and the shear stress was 0.4 × 10 ⁶ dyn / c.
Shear speed γ ₁ when showing m ² and shear stress 2.4 × 1
The ratio of the shear rate γ ₂ when showing 0 ⁶ dyn / cm ² was determined. Effective network chain density (ν): JIS K 6258 (199
3 years), the sample was immersed in toluene at 37 ° C. for 72 hours, and the effective network chain density was calculated using the Flory-Rehner equation.

* The expression of Flory-Rehner is as follows. [nu (pieces ^{/ cm 3) = [νR +} ln (1-νR) + μνR 2
] / [− V0 (νR ^1/3 −νR / 2)] Here, the meaning of each symbol in the above formula is as follows. ν (pieces / cm ³ ): effective mesh chain density. Number of effective network chains in 1 cm ^{3 of} pure rubber νR: Volume fraction of pure rubber to volume of pure rubber (volume of pure rubber + volume of absorbed solvent) in swollen vulcanized rubber μ: between rubber and solvent Interaction constant (0.49) V0: molecular volume of solvent

(Method for Preparing Test Sample) Copolymer 10
To 0 g, 0.01 mol of dicumyl peroxide was added and kneaded at a temperature of 50 ° C. As the test kneading roll machine, a 150 × 330 mm (6 × 13 type) standard kneading roll for testing specified in SRIS 2603 (standard kneading roll machine for rubber) is used. The temperature of the roll machine is set to 50 ± 2 ° C., the gap between the rolls is adjusted to 0.5 mm, the rubber is wound around the high-speed side, and 3/4 turnover is performed once for each of the left and right sides. Time required 1.0 minute.

Thereafter, dicumyl peroxide 0.01
Mole is added and 3/4 switching is performed alternately left and right three times. The “3/4 turn” means that the roll is cut by ／ of the roll width, and the cut is made with a knife until the pool on the roll is no longer visible. This operation is performed alternately on the left and right every 30 seconds. The required time is 13.0 minutes. The batch is cut from the roll and rounded six times with a roll gap of about 0.5 mm. Time required 2.0 minutes. The batch is weighed and the change in mass must be within ± 1% of the total mass.
The final thickness was adjusted to about 2.2 mm, and the vulcanization product was taken out.
Press vulcanize for 0 minutes, and use this as a sample for test measurement.

(Production method of terpolymer) The ethylene / α-olefin / polyene amorphous copolymer used in the following Examples and Comparative Examples was produced by the following method. Ternary copolymerization was continuously performed using a stainless polymerization vessel (stirring rotation speed = 250 rpm) having a substantial internal volume of 100 liters equipped with stirring blades. 60 liters of hexane / hour, ethylene, propylene, polyene, hydrogen, and a catalyst were continuously supplied from the side of the polymerization vessel to the liquid phase at the rates shown in Table 1. Table 1 summarizes the main polymerization conditions.

As a result, ethylene / α-olefin /
A polyene amorphous copolymer was obtained in the form of a homogeneous solution, which was continuously withdrawn from the lower part of the polymerization vessel, and a small amount of methanol was added to the polymerization solution to stop the copolymerization reaction.
The polymer was separated from the solvent by performing a steam stripping treatment, and vacuum dried at 55 ° C. for 48 hours. The physical properties of the obtained copolymer were evaluated according to the above-mentioned measurement methods, and the results are shown in Table 1.

[0072]

[Table 1]

(Examples 1 to 3) First, silicone rubber (trade name: Silicone rubber SH871U: vinyl group content 0.1 mol%, weight average molecular weight 440 × 10 ³ ) 100
Organic peroxide (dicumyl peroxide; product of Mitsui Chemicals, trade name: Mitsui DCP-40C) 1.0 by weight
Parts by weight, and 40-
The mixture was kneaded at 50 ° C. for 10 minutes to obtain a compound (A).

On the other hand, ethylene-propylene
5-vinyl-2-norbornene (VNB) copolymer rubber 1
00 parts by weight of an organic peroxide (dicumyl peroxide; a product of Mitsui Chemicals, Inc., trade name: Mitsui DCP-40)
C) 1.0 part by weight and 30.0 parts by weight of silica (dry silica; a product of Wacker Inc., trade name N20P) were added, and 8 parts by weight were added.
The mixture was kneaded at 40 to 50 ° C. for 20 minutes using an inch open roll to obtain a compound (B). The copolymer rubber used herein had a molar ratio of ethylene / propylene of 75.
/ 25, the iodine value was 11.5, and the intrinsic viscosity in a 135 ° C decalin solution was 1.90 (dl / g).

Next, the compounds (A) and (B) were mixed at the weight ratio shown in Table 2, and kneaded again using an 8-inch open roll according to the SRIS standard.

[Table 2]

Next, the kneaded rubber compound was press-vulcanized at 170 ° C. for 10 minutes to produce a vulcanized rubber sheet having a thickness of 2 mm. Using this sheet, JIS K6251
Subjected to a tensile test in accordance with the tensile strength (TB), elongation at break (EB), it was determined 100% tensile stress (M _100).

Further, using this sheet, JIS K6
The boiling water resistance was measured according to 258. The immersion condition was 48 hours in boiling water, and the measurement item was the volume change rate ΔV (%). Further, the heat aging resistance was measured according to JIS K6257. The heat aging conditions were set at 160 ° C. for 72 hours, the tensile strength after the test and the elongation at break were measured, and the rate of change with respect to each value before the test was used as an index of the heat aging resistance. Further, press molding was carried out a plurality of times under the same conditions, and the number of times until the mold was contaminated was examined, and the mold contamination was evaluated. Table 3 shows the physical property measurement results.

Comparative Example 1 The procedure of Example 1 was repeated except that the compound (A) used in Example 1 was used as it was in the experiment, and the results are shown in Table 3.

Comparative Example 2 Example 1 was carried out in the same manner as in Example 1 except that the compound (B) used in Example 1 was used as it was in the experiment, and the results are shown in Table 3.

(Comparative Examples 3 to 5) In Examples 1 to 3,
Same as Example 1 except that instead of the ethylene / propylene / 5-vinyl-2-norbornene copolymer rubber, an ethylene / propylene / dicyclopentadiene (DCPD) copolymer rubber (compound B2) shown in Table 1 was used. I went to. Table 3 shows the results.

[0081]

[Table 3]

(Comparative Examples 6 to 8) In Examples 1 to 3,
The procedure was performed except that the ethylene / propylene / 5-ethylidene-2-noribonene (ENB) copolymer rubber (Compound B3) shown in Table 1 was used instead of the ethylene / propylene / 5-vinyl-2-norbornene copolymer rubber. Example 1
The same was done. Table 3 shows the results.

Comparative Examples 9 to 11 In Examples 1 to 3, instead of the ethylene / propylene / 5-vinyl-2-norbornene copolymer rubber, ethylene / propylene / 1,4-hexadiene (Table 1) was used. (1,4HD) Copolymer rubber (compound B4) was used in the same manner as in Example 1. Table 3 shows the results.

[0084]

According to the present invention, a rubber composition capable of obtaining an appropriate vulcanization density at a high vulcanization speed by combining a silicone rubber and an ethylene / α-olefin / polyene amorphous copolymer is provided. Obtained. As a result, a vulcanized rubber product having high mechanical strength, excellent processability and rubber elasticity can be provided.

This rubber composition improves the lack of strength and the lack of water resistance of silicone rubber,
Insufficiency of heat aging resistance and mold contamination of the α-olefin / polyene amorphous copolymer were able to be improved.
It is not clear why this improvement effect was achieved, but one of the reasons is that the ethylene / α-olefin / polyene amorphous copolymer (B) contains a specific polyene component, so that the radical reactivity is increased. As a result, it is believed that the co-crosslinking property between the silicone rubber and the ethylene / α-olefin / polyene amorphous copolymer was improved.

Accordingly, the vulcanizable rubber composition according to the present invention has rubber properties excellent in strength, water resistance, heat aging resistance, and mold contamination resistance, so that it can be used for industrial parts and electric parts. , Can be widely used in the field of civil engineering and building components.

As industrial parts, belts, rubber rolls,
It can be used for hoses, boots, gaskets, packing and the like. The electric parts can be used for caps such as plug caps, distributor caps, condenser caps, etc., and electric insulating layers such as marine electric wires and ignition cables. For civil engineering construction materials, it can be used for building gaskets, highway joint seals, and the like.

Claims (9)

[Claims] 1. The silicone rubber (A) is 2 to 98% by weight.
And 98 to 2% by weight of an ethylene / α-olefin / polyene amorphous copolymer (B), wherein the polyene is at least one kind of a vinyl terminal group represented by the following general formula [I] or [II]: Containing norbornene compound Here, n is an integer of 0 to 10, R ¹ is hydrogen or an alkyl group having 1 to 10 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 5 carbon atoms, Here, R ³ is hydrogen or an alkyl group having 1 to 10 carbon atoms, a vulcanizable rubber composition. 2. The vulcanizable rubber composition according to claim 1, wherein the silicone rubber (A) is a silicone having a vinyl group. 3. The vulcanizable rubber composition according to claim 2, wherein the silicone rubber (A) contains 0.02 to 2.0 mol% of a vinyl group. 4. The ethylene / α-olefin / polyene amorphous copolymer (B) comprises: (1) an α-olefin having 3 to 20 carbon atoms; and (2) an ethylene / α-olefin having a ratio of 40/60. ~ 95/5
(3) the iodine value is 0.5 to 50, and (4) the intrinsic viscosity of the decalin solution at 135 ° C. is 0.5 to 1.
0 (dl / g), and (5) the molecular weight distribution (Mw / Mn) measured by GPC is 3 to
The vulcanizable rubber composition according to claim 1, wherein the composition is 50. 5. The ethylene / α-olefin / polyene amorphous copolymer (B) is prepared by mixing (6) 0.01 g of dicumyl peroxide with 100 g of the copolymer at 170 ° C. for 10 minutes. The effective network chain density (ν) when cross-linked by press at 1.5 × 10 ²⁰
A to 100 × 10 ²⁰ atoms / cm ^3, (7) melt flow at 100 ° C. - Ca - obtained from blanking, the shear rate gamma ₁ when the shear stress indicates 0.4 × 10 ⁶ dyn / cm ² The relationship between the ratio γ ₂ / γ ₁ to the shear rate γ ₂ when the shear stress is 2.4 × 10 ⁶ dyn / cm ² and the effective network chain density (ν) is represented by the following relational formula [III]. 0.04 × 10 ⁻¹⁹ ≦ log (γ ₂ / γ ₁ ) /ν≦0.20×10 ⁻¹⁹ ... [III] The vulcanizable rubber composition according to claim 4, characterized in that: 6. The ethylene / α-olefin / polyene amorphous copolymer (B) is an ethylene / propylene / 5-methylene-2-norbornene random copolymer or ethylene / propylene / 5-vinyl-2-norbornene. The vulcanizable rubber composition according to claim 1, which is a random copolymer. 7. A silicone rubber (A) and ethylene.
The organic peroxide is 1 × 10 ^{−3 to} 5 × 10 ³ per 100 g of the α-olefin / polyene amorphous copolymer (B) in total.
The vulcanizable rubber composition according to claim 1, wherein ^-2 mol is blended. 8. The organic peroxide has a temperature of 130 to 200 ° C. to give a half-life of 1 minute.
The vulcanizable rubber composition according to the above. 9. An organic peroxide comprising dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane,
-Butylcumyl peroxide, di-t-amyl peroxide, t-butyl hydroperoxide, 1,1-
The vulcanizable rubber composition according to claim 7, which is any one selected from the group consisting of bis-t-butylperoxy-3,3,5-tri-methylcyclohexane.