JPH0680129B2 - Vulcanizable acrylic rubber composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vulcanizable acrylic rubber composition, and more specifically, to an acrylic rubber composition capable of improving low temperature flexibility without deteriorating heat resistance and oil resistance of the acrylic rubber. It relates to a vulcanizable acrylic rubber composition.

BACKGROUND ART Acrylic rubber is used for various seals, packings, gaskets, hoses and other functional parts mainly for automobile parts by taking advantage of its excellent heat resistance, lubricating oil resistance and weather resistance.

However, it has a drawback that it becomes hard at low temperatures and loses rubber-likeness, and therefore, measures such as changing the ester group have been made, but this is not sufficient.

SUMMARY OF THE INVENTION AND OBJECTS The present inventors have found that when an ethylene / α-olefin copolymer rubber having an average particle diameter and a hot toluene insoluble amount in a certain range is blended with an acrylic rubber, the heat resistance, oil resistance, etc. of the acrylic rubber It was found that the low temperature characteristics can be remarkably improved without impairing the various characteristics.

That is, an object of the present invention is to provide a vulcanizable acrylic rubber composition having excellent properties at low temperature without deteriorating the excellent properties of acrylic rubber.

According to the present invention, the acrylic rubber (A) and ethylene / α-
A / B = 95/5 by weight based on olefin copolymer rubber (B)
To 20/80, wherein the ethylene / α-olefin copolymer rubber (B) has a mean particle size of 0.2 to 50 μm and a hot toluene insoluble content of 30% by weight or more. A vulcanizable acrylic rubber composition is provided, which is rubber particles, and the crosslinked rubber particles are uniformly dispersed in acrylic rubber.

BEST MODE FOR CARRYING OUT THE INVENTION Acrylic rubber (A) The acrylic rubber used in the present invention comprises a homopolymer of an alkyl ester of acrylic acid or methacrylic acid or a second component containing the alkyl ester as a main component and having an active group to be a crosslinking point. Among these polymers, those having a Mooney viscosity ML _{1 + 4} (100 ° C.) in the range of 10 to 180 are preferably used from the viewpoint of moldability, workability and the like.

Examples of the alkyl ester of acrylic acid or methacrylic acid include, but are not limited to, ethyl acrylate, propyl acrylate, butyl acrylate, methoxyethyl acrylate, other methyl methacrylate, ethyl methacrylate and the like. .

As the second component having an active group serving as a crosslinking point, 2-chloroethyl vinyl ether, vinyl chloroacetate,
Allyl chloroacetate, glycidyl methacrylate,
Glycidyl acrylate, ethylidene norbornene, dicyclopentadiene and the like can be used alone or in combination of two or more kinds. These second components are generally used in amounts of not more than 15% by weight, in particular not more than 10% by weight, based on the main constituent alkyl ester of acrylic acid or methacrylic acid.

Although these acrylic rubbers have various excellent properties such as heat resistance, oil resistance, and weather resistance, they are insufficient in low-temperature properties such as impact strength at low temperatures. -To blend the olefin copolymer rubber to solve the above-mentioned drawbacks.

Ethylene / α-olefin copolymer rubber (B) In the present invention, the ethylene / α-olefin copolymer rubber (B) used in combination with the acrylic rubber (A) is ethylene and α-olefin, such as propylene or 1-butene, 1
-Pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and the like having 3 to 10 carbon atoms α
A copolymer with one or more olefins.

The ethylene content is usually 50 to 95 mol%, preferably 6
0 to 92 mol%, the intrinsic viscosity [η] measured in 135 ° C decalin is 0.5 to 4.5 dl / g, preferably 0.8 to 3.0
It is in the range of dl / g.

Furthermore, this ethylene / α-olefin copolymer rubber has 1
One or more polyene components may be contained.

Specifically as the polyene component, 1,4-hexadiene,
1,6-octadiene, 2-methyl-1,5-hexadiene,
Chain non-conjugated dienes such as 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-
Norbornene, 5-methylene-2-norbornene, 5-
Cyclic non-conjugated dienes such as isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5
Typical examples are trienes such as -norbornene, 2-propenyl-2,2-norbornadiene, 1,3,7-octatriene and 1,4,9-decatriene.
Suitable polyenes are cyclic non-conjugated dienes and 1,4-bexadiene, especially dicyclopentadiene or 5-ethylidene-2-norbornene. These polyene components are
The resulting copolymer is copolymerized so that the iodine value is at most 30, preferably 20 or less.

The ethylene / α-olefin copolymer rubber as described above is
For example, it can be produced by a method known per se, as described in Synthetic Rubber Processing Technology "Ethylene Propylene Rubber" (Taisei Co., Ltd.).

That is, in the medium, using a Ziegler catalyst such as a soluble vanadium compound and an organoaluminum compound, ethylene,
It is produced by supplying α-olefin having 3 to 10 carbon atoms, polyene if necessary, and hydrogen gas as a molecular weight modifier. Examples of the medium include aliphatic hydrocarbons such as pentane, hexane, heptane, octane and kerosene, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbon hydrogens such as benzene, toluene and xylene, chlorobenzene and tetrachloride. Carbon, hydrogenated hydrocarbon valences such as tetrachloroethylene, trichloroethylene, ethyl chloride, methylene chloride and dichloroethane can be used alone or in combination. Examples of the soluble vanadium compound include vanadium tetrachloride, vanadyl trichloride, vanadium triacetylacetonate,
Vanadyl acetylacetonate, vanadyl trialkoxide VO (OR) ₃ (wherein R represents an aliphatic hydrocarbon group)
Halogenated vanadyl alkoxide VO (OR) _n X _3-n (wherein R is an aliphatic hydrocarbon group, X is a halogen atom, and 0 <n <3) is used alone or in combination. be able to. On the other hand, as the organoaluminum compound, a compound represented by the general formula R _m AlX _3-m (wherein R represents an aliphatic hydrocarbon group, X represents a halogen, and 1 ≦ m ≦ 3), for example, triethylaluminum, Diethyl aluminum chloride, ethyl aluminum sesquichloride,
Ethyl aluminum dichloride and the like can be used alone or in combination.

Further, the above ethylene / α-olefin copolymer rubber is
It may be modified with halogen. In this case, the halogen content is 40% by weight or less, preferably 30% by weight or less. When the halogen content exceeds the above range, it becomes difficult to achieve the initial purpose of improving the low temperature characteristics.

This halogenated ethylene / α-olefin copolymer rubber can be manufactured as follows.

First, for chlorination of ethylene / α-olefin / copolymer rubber, the copolymer rubber is pulverized, for example, into fine particles, and the fine particles are dispersed in an aqueous state, and molecular chlorine is usually added at a temperature of about 70 to 90 ° C. It can be carried out by a method of contacting, a method of dissolving the copolymer rubber in a solvent which is stable against chlorine such as carbon tetrachloride and tetrachloroethylene, and bringing it into contact with molecular chlorine in a uniform solution state.

In addition, when performing chlorination using molecular chlorine, the chlorination reaction rate can be significantly increased by irradiation with light.
It is like a conventional finding.

The treatment after the chlorination reaction is usually performed as follows. In the case of chlorination in an aqueous dispersion state, the chlorinated rubber is separated from molecular chlorine by washing with water and dried. In the case of chlorination in a solution state, the reaction product solution is put into a poor solvent for chlorinated rubber, such as excess methanol, the precipitate is filtered, washed with this solvent, and then dried.

In order to control the degree of chlorination, the amounts of molecular chlorine and other chlorinating agents used, the reaction time, the reaction temperature, etc. may be appropriately selected. The chlorine content is usually adjusted to about 15-40% by weight, preferably about 20-35% by weight at this stage.

When molecular bromine is used instead of molecular chlorine, it is natural that brominated rubber is similarly produced.

It is preferable to add about 0.05 to 2 parts by weight of a hydrochloric acid absorbent, an antioxidant and a metal deactivator to each of these halogenated rubbers per 100 parts by weight of the halogenated rubber.

As the hydrochloric acid absorbent, an organic acid salt of Group IIA metal of the periodic table, for example, magnesium stearate, calcium stearate, manacea soto, hydrotalcite, epoxidized soybean oil, epoxy-based hydrochloric acid absorbent, and the like, as an antioxidant, Di-t-butylhydroxytoluene, tetrakis [methylene (3,5-di-t-butyl-4-hydroxy) hydrocinnamate] methane, d, l-α-tocopherol, phenyl-β-naphthylamine, triphenylmethane, Metal deactivators such as 1,4-benzoquinone include tris (nonylphenyl) phosphite, isopropyl citrate, pentaerythritol, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene-di- Examples thereof include phosphite.

These show remarkable effects in stabilizing the hue of the halogenated rubber and preventing gelation.

The ethylene / α-olefin copolymer rubber (B) used in the present invention has an average particle size of 50 μm or less, preferably 45 μm or less, particularly 0.2 to 40 μm, and hot toluene. Insoluble content is 30% by weight or more,
In particular, it is important that the resin is crosslinked so as to be 40% by weight.

When the average particle size is larger than the above range, the particle size of the copolymer rubber particles in the rubber composition becomes large, and the properties such as oil resistance and heat resistance of the composition are impaired.

If the hot toluene insoluble content is lower than the above range, it becomes difficult to atomize the ethylene / α-olefin copolymer rubber. For example, in the process of drying or kneading, the rubber particles agglomerate and become coarse, and eventually the average particle size of the copolymer rubber particles in the rubber composition becomes larger than 50 μm. As a result, the oil resistance and heat resistance are the same as above. And other characteristics are impaired.

This hot toluene insoluble content is an index showing the degree of crosslinking of the rubber component and is quantified as follows.

That is, ethylene-α-olefin copolymer rubber dried after salting out crosslinked latex described below is precisely weighed and put into a basket of a wire mesh of 200 mesh, and left in a large excess of boiling toluene. After 6 hours, the basket is taken out and the insoluble matter is precisely weighed to obtain hot toluene insoluble matter.

In the present invention, among the above-mentioned ethylene / α-olefin copolymer rubbers, those having the above-mentioned physical properties are blended with the acrylic rubber (A) so that the acrylic rubber has It is possible to remarkably improve the low temperature characteristics without deteriorating the characteristics such as heat resistance and oil resistance.

The adjustment of the average particle size of the ethylene / α-olefin copolymer rubber and the amount of hot toluene insoluble matter is carried out by making the copolymer rubber into a latex, crosslinking in the latex state, and then drying it. Done.

(I) Making latex of ethylene / α-olefin copolymer rubber To manufacture ethylene / α-olefin copolymer rubber latex, ethylene / α-olefin copolymer rubber is dissolved in a solvent such as toluene or hexane, and a surfactant is dispersed. It can be produced by a method of removing the solvent after emulsification in water.

For the emulsification in water, a known method such as a method using a homomixer equipped with a high speed stirring blade or a high speed pipe emulsifier can be used.

Alternatively, organic solvent in a multi-screw extruder,
A method of producing a latex by using an emulsifier and at most about 20 wt% of water can be used.

In any case, partially saponified polyvinyl alcohol, EVA (ethylene / vinyl acetate copolymer) as an emulsification aid
It is well known that stable latex can be obtained by adding modified polyethylene wax or the like.

(Ii) Crosslinking of ethylene / α-olefin copolymer rubber latex and drying. Crosslinking and tourism of ethylene / α-olefin copolymer rubber latex prepared as described above. Ethylene / α-olefin copolymer weight prepared as described above. The combined rubber latex is subjected to a crosslinking reaction in the latex state.

This crosslinking is effectively performed by, for example, crosslinking with an organic peroxide or crosslinking with an electron beam.

As the organic peroxide used, stability of latex particles,
From the viewpoint of stability and economy of the crosslinking reaction operation, those having a 10-hour half-life temperature of 0 ° C. or higher and 100 ° C. or lower are preferable, and specific examples thereof include the following organic peroxides.

1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxybiparate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2 5,5-di (benzoylperoxy) hexane, 3,5,5, -trimethylhexanoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, isobutyl peroxide, diisopropylperoxide Oxydicarbonate, di (2-ethylhexyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane.

The amount of the organic peroxide used varies depending on the degree of crosslinking required, but in the present invention, it is usually 3 × 10 ^{−4 to} 5 × 10 ⁻² per 100 parts by weight of the ethylene / α-olefin copolymer rubber.
The amount of hot toluene insoluble matter can be adjusted within the above-mentioned range by using it in the range of 10 ^{−3 to} 3 × 10 ⁻² mol.

For crosslinking with an organic peroxide, it is preferable to use a crosslinking aid together.

Examples of the cross-linking aid include sulfur, quinone dioximes such as p-quinone dioxime, methacrylates such as polyethylene glycol dimethacrylate, allyls such as diallyl phthalate and triallyl cyanurate, other maleimides, and divinylbenzene. To be done. Such a vulcanization aid is based on 1 mol of the organic peroxide used.
1/2 to 2 mol, preferably about equimolar amount is used.

These organic peroxides and crosslinking aids may be blended in advance before the production of the latex or may be blended after the production of the latex.

The heating time for crosslinking is usually 5 to 10
It is preferably doubled, and it can be performed under either normal pressure or increased pressure.

In the electron beam crosslinking, the absorbed dose is selected according to the required degree of crosslinking, but in the case of the present invention, it is usually 1 to 100M.
It is controlled in the range of rad, preferably 5 to 30 Mrad. Also in such electron beam crosslinking, the crosslinking efficiency can be improved by adding a crosslinking aid in advance.

In order to collect fine rubber powder from the thus obtained crosslinked ethylene / α-olefin copolymer rubber latex, salting out is carried out with stirring, water is allowed to pass and then dried by heating.

The ethylene / α-olefin copolymer rubber obtained as described above is fine particles having an average particle size of 50 μm or less and a hot toluene insoluble content of 30% by weight or more. This ethylene / α-olefin copolymer rubber is extremely unique in that it does not cause mutual aggregation between rubber particles during heating and drying, and that a dry product can be obtained while maintaining the fine particle size in the latex state. It has various properties.

The rubber particles thus obtained are extremely fine particles having an average particle size of 50 μm or less, preferably 45 μm or less, and particularly 0.2 to 40 μm. This property is exhibited even when kneading with the acrylic rubber (A), and even in the rubber composition, the ethylene / α-olefin copolymer rubber (B) maintains the average particle size of 50 μm or less. It is evenly dispersed.

Acrylic Rubber Composition The vulcanizable acrylic rubber composition of the present invention comprises the above-mentioned acrylic rubber (A) and ethylene / α-olefin copolymer rubber (B) on a weight basis, A / B = 95/5 to. 20/80 It is obtained by blending in a ratio of 80/20 to 40/60.

If the blending amount of the ethylene / α-olefin copolymer rubber (B) is less than the above range, the low temperature characteristics, particularly the flexibility at low temperature, will be impaired. As a result of deterioration of the property, there arises a problem that processing becomes difficult.

The acrylic rubber composition of the present invention is characterized in that the ethylene / α-olefin copolymer rubber (B) is dispersed in the acrylic rubber phase of the composition in an extremely fine state with an average particle size of 50 μm or less. ing.

When the average particle size of the dispersed rubber particles is larger than 50 μm, the strength of the vulcanized product obtained from this rubber composition is lowered and it becomes difficult to put it into practical use.

The average particle size of the ethylene / α-olefin copolymer rubber particles in the rubber composition of the present invention is measured as follows.

That is, the composition was frozen and cut, and the cut surface was immersed in cyclohexane at 60 ° C. for 1 hour to disperse ethylene / α in the composition.
-After removing the olefin copolymer rubber, observe the major axis and number of dispersed rubber particles for each of the three areas by electron microscope and select 50 areas to about 100 dispersed rubber particles. The particle size was calculated and the average value of the three regions was used as the average particle size.

Example Area 1 Number average particle size A ₁ 〃 2 〃 A ₂ 〃 3 〃 A ₃ In the rubber composition of the present invention, a compounding agent known per se, such as a rubber reinforcing agent, a filler, a softening agent, a vulcanizing agent, a vulcanization aid, etc., depending on the intended use of the vulcanized product, etc. It can be blended.

In this case, the total amount of the acrylic rubber (A) and the ethylene / α-olefin copolymer rubber (B) that occupy in the composition is usually 30% by weight or more, and particularly 40% by weight or more, although it varies depending on the use. It is preferable to set it as follows.

Examples of rubber reinforcing agents that can be used are SRF, GPF, FEF and HA.
Examples include carbon black such as F, ISAF, SAF, FT, MT, and fine silicic acid.

Examples of the rubber filler include soft calcium carbonate, heavy calcium carbonate, talc and clay.

These rubber reinforcing agents and fillers can be appropriately selected according to their applications, but the acrylic rubber (A) and ethylene / α
The amount is usually 200 parts by weight or less, preferably 150 parts by weight or less, based on 100 parts by weight of the total amount of the olefin copolymer rubber (B).

As the softening agent which can be used in the present invention, a softening agent which is usually used for rubber is sufficient. For example, petroleum-based softening agents such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, petrolatum, coal tar, coal tar. Coal tar softeners such as Pitch, castor oil, linseed oil, rapeseed oil, coconut oil and other fatty oil softeners, tall oil; sub; beeswax, carnauba wax, lanolin and other waxes; ricinoleic acid, palmitic acid, Fatty acids and fatty acid salts such as barium stearate, calcium stearate and zinc laurate; synthetic polymer substances such as petroleum resin, atactic polypropylene, coumarone indene resin and polyester resin, or ester plastics such as dioctyl adipate and dioctyl phthalate Agents Others Microcrystalline Try, sub (Fuakuchisu)
And so on.

The blending amount of these softening agents can be appropriately selected according to the application, but is usually a maximum of 7 per 100 parts by weight of the total amount of the acrylic rubber (A) and the ethylene / α-olefin copolymer rubber (B).
0 parts by weight, preferably up to 40 parts by weight, is added.

As the vulcanizing agent, the vulcanizing agent usually used for acrylic rubber is sufficient, and zinc, iron, dimethylthiocarbamic acid,
Alternatively, amine salts, ammonium benzoates, polyamines, 2-mercaptoimidazoline and red lead, fatty acid metal salts and sulfur, etc. can be exemplified.

Also, it is possible to extend the material life of the vulcanizate obtained from the composition of the present invention by using an antioxidant, as in the case of ordinary rubber. Examples of the antioxidant used in this case include aromatic secondary amines such as phenylnaphthylamine and N, N'-di-2-naphthyl-p-phenylenediamine, dibutylhydroxytoluene, tetrakis [methylene (3 , 5-di-t-butyl-
4-Hydroxy) hydrocinnamate] methane and other sterically hindered phenol stabilizers and dithiocarbamic acid stabilizers can be exemplified.

The amount of such an antiaging agent used is acrylic rubber (A)
And usually 0.1 to 5 parts by weight, preferably 100 parts by weight with the ethylene / α-olefin copolymer rubber (B), preferably
Choose from 0.5 to 3 parts by weight.

The rubber composition of the present invention is usually prepared by the following method.

That is, a mixer such as a Banbury mixer is kneaded with acrylic rubber, ethylene / α-olefin copolymer rubber, a filler and a softening agent at a temperature of 80 ° C to 150 ° C for 3 to 10 minutes, and then a roll such as an oven roll. A vulcanizing agent is additionally mixed using a mixture, and the mixture is kneaded at a roll temperature of 40 ° C to 80 ° C for 5 to 8 minutes and then dispensed to obtain a ribbon-shaped or sheet-shaped rubber composition.

Vulcanizate The rubber composition prepared as described above is molded into a desired shape by an extruder, calender roll, press or the like, and at the same time as molding or by introducing the molded product into a vulcanization tank, usually 130 ° C. The vulcanized product can be obtained by heating at a temperature of to 230 ° C. for usually 1 to 30 minutes.

This vulcanization step may be carried out using a mold or may be carried out without using a mold.

After that, when secondary vulcanization is performed at a temperature of 140 ° C. to 200 ° C. for 1 hour to 20 hours, it is as is conventionally known that the performance of the vulcanized product is further improved.

The vulcanizates produced as described above are used for various heat resistance of automobiles and machinery, oil resistant packing, gaskets, oil seals, O-rings, oil cooler hoses, power steering hoses, electrical wiring convergence covers for various electrical equipment and instruments. Can be used for ring hoses, etc. For general industrial use, it can be suitably used for bearing seals, conveyor belts, rolls, tank linings, and for the electric industry, electric wire cable jackets.

Hereinafter, the present invention will be described based on Examples.

Reference Example 1. 100 g of ethylene / propylene copolymer rubber (ethylene content: 60 mol%, iodine value: 20, polyene component: ethylidene norbornene, intrinsic viscosity [η] decalin 135 ° C .: 1.7) and modified polyethylene wax (Mitsui Hiwax 1105A ) 10g
Was dissolved in 900 g of n-hexane and stirred until uniform. On the other hand, 5 g of potassium oleate as a surfactant is added to water.
After being dispersed in 900 g, the above solution was mixed with a homomixer at a rotation speed of 10,000 rpm for 30 minutes. The obtained emulsion was transferred to an evaporator and stirred at 60 rpm while stirring at 60
The n-hexane was removed under reduced pressure at a temperature of ~ 80 ° C.

Reference Example 2. 100 g of ethylene / propylene copolymer rubber (ethylene content: 60 mol%, iodine value: 20, polyene component: ethylidene norbornene, intrinsic viscosity [η] decalin 135 ° C .: 1.7) and modified polyethylene wax (Mitsui High-Sox 1105A ) 5g
Was dissolved in 900 g of n-hexane and stirred until uniform.
On the other hand, 5 g of potassium oleate as a surfactant is added to 900 g of water.
After dispersing in the solution, use a homomixer to
Mix for 30 minutes at 2000 rpm. The obtained emulsion is transferred to an evaporator and stirred at 60 rpm for 60-80 ° C with stirring.
N-hexane was removed under reduced pressure at the temperature of.

Reference Example 3. 100 g of ethylene / propylene copolymer rubber (ethylene content: 60 mol%, iodine value: 20, polyene component: ethylidene norbornene, intrinsic viscosity [η] decalin 135 ° C .: 1.7) and modified polyethylene wax (Mitsui Hiwax 1105A ) 3 g
Was dissolved in 900 g of n-hexane and stirred until uniform. On the other hand, 5 g of potassium oleate as a surfactant is added to water.
After being dispersed in 900 g, the solution was mixed with a homomixer at a rotation speed of 500 rpm for 30 minutes. The obtained emulsion is transferred to an evaporator and stirred at 60 rpm and stirred at 60 to 80 ° C.
N-hexane was removed under reduced pressure at the temperature of.

Reference Example 4. 100 g of ethylene / 1-butene copolymer rubber (ethylene content 92 mol%, intrinsic viscosity [η] decalin 135 ° C .: 1.2) was dissolved in 4 liters of carbon tetrachloride, and this was equipped with a stirrer and a thermometer. While maintaining the temperature of the glass reaction vessel with a volume of 6 liters at 60 ° C, while irradiating a 20W daylight fluorescent lamp from the outside of the vessel, chlorine gas was introduced into the reaction vessel at a rate of 2.0 g / min and the chlorination reaction for 70 minutes. Was done. Then, nitrogen gas was passed through the reaction vessel,
Excess chlorine gas was removed.

Next, a large excess of methanol was added to this solution to precipitate a chlorinated rubber. After filtration, this was dried under reduced pressure at room temperature.

The chlorine content of the chlorinated ethylene / 1-butene copolymer rubber thus obtained was 28 wt% as measured by the cylinder combustion method.
It was in%.

100 g of this chlorinated ethylene / 1-butene copolymer rubber was dissolved in 900 g of toluene and stirred until uniform. On the other hand, as a surface active agent, potassium oleate 5 g was dispersed in 900 g of water, and then the solution and the rotation speed were 10,000 rpm using a homomixer.
Mix for 30 minutes. The obtained emulsion was transferred to an evaporator, and toluene was removed under reduced pressure at a temperature of 80 to 100 ° C while stirring at 60 rpm while stirring.

Example 1. The ethylene / propylene rubber latex obtained in Reference Example 1 was impregnated with a mixture of 2.0 parts by weight of perhexa3M and 2.0 parts by weight of divinylbenzene per 100 parts by weight of a rubber content, and then in a glass autoclave. The mixture was heated at 120 ° C. for 5 hours with stirring.

Excessive hydrochloric acid water was added to this under stirring at 100 rpm, and a rubber component was deposited and filtered. This is washed 3 times with 200 ml of water and at 50 ℃
The product was dried under reduced pressure at, and was named Prototype A.

The hot toluene insoluble content of the prototype A was determined as follows. That is, make a screen basket with a wire mesh of 200 mesh, accurately weigh about 0.2 g of prototype A to the 0.1 mg unit, and leave it in 300 ml of boiling toluene for 6 hours,
The insoluble matter remaining in the screen basket was dried at 50 ° C. under reduced pressure for 3 hours, allowed to cool to room temperature and precisely weighed to 0.1 mg unit, and the proportion of the insoluble matter was taken as the hot toluene insoluble matter.

Trial product A and a commercially available acrylic rubber were mixed in the following formulation to be tested.

Kneading is carried out using an 8-inch oven roll at 20 ℃ at 30 ℃ ～ 40 ℃.
I went for a minute. The dispersion state of the prototype A in the kneaded material was investigated as follows. That is, the kneaded material was frozen in methanol cooled to -70 ° C with dry ice, and this was cut using a microtome. The cut surface was immersed in cyclohexane at 60 ° C. for 1 hour and subjected to ultrasonic treatment for 1 minute. This cut surface was observed with an electron microscope to determine the number average particle size of the prototype A.

Next, the kneaded material was press-vulcanized at 150 ° C. for 10 minutes to prepare a vulcanized rubber sheet having a thickness of 2 mm. This vulcanized rubber sheet 150
Secondary vulcanization was carried out for 15 hours in an air oven at ℃ for measurement. The following items were measured according to the method of JIS K 6301.

Normal physical properties Tensile strength (T _B ), Elongation (E _B ), Spring hardness (H _S ),
Permanent elongation (PS) Heat aging resistance (aging condition: 160 ° C-70 hours in air oven) Tensile strength retention rate (A _R (T _B )), Elongation retention rate (A _R (E _B )) Oil resistance [Oil resistance Conditions: 50 ° C.-7 days in JIS No. 3 oil] Swelling ratio (Δv) Low temperature characteristics Embrittlement temperature (Tb) The results are shown in Table 1 below.

Example 2 In Example 1, the formulation was as follows.

Except for this, the procedure was exactly the same as in Example 1.

The results are shown in Table 1 below.

Example 3. Except for this, the procedure was exactly the same as in Example 1.

The results are shown in Table 1 below.

Comparative Example 1. The following formulation was used without using the prototype A in Example 1.

Except for this, the procedure was exactly the same as in Example 1.

The results are shown in Table 1 below.

Comparative Example 2. In Example 1, the following formulation was used without using any acrylic rubber.

With this composition, it could not be processed because it was not wrapped around an open roll.

Comparative Example 3. The ethylene / propylene rubber latex obtained in Reference Example 1 was impregnated with a mixture of 0.1 parts by weight of perhexa3M and 0.1 parts by weight of divinylbenzene per 100 parts by weight of the rubber content, and then in a glass autoclave. The mixture was heated at 120 ° C. for 5 hours with stirring.

Excessive hydrochloric acid water was added to this under stirring at 100 rpm, and a rubber component was deposited and filtered. This is washed 3 times with 200 ml of water and at 50 ℃
The product was dried under reduced pressure in, and this was named prototype B.

In the same manner as in Example 1, hot toluene insoluble matter was obtained. Further, the same test as in Example 1 was carried out except that Prototype B and commercial acrylic rubber were mixed in the following formulation.

The results are shown in Table 1 below.

Comparative Example 4. Ethylene / propylene copolymer rubber (ethylene content: 60 mol%, iodine value: 20, polyene component: ethylidene norbornene, intrinsic viscosity [η] decalin 135 ° C .: 1.7) and a commercially available acrylic rubber were compounded in the following formulation. did.

Except for this, the same test as in Example 1 was carried out.

The results are shown in Table 1 below.

Example 4 The ethylene / propylene rubber latex obtained in Reference Example 2 was impregnated with a mixture of 2.0 parts by weight of Perhexa 3M and 20 parts by weight of divinylbenzene with respect to 100 parts by weight of rubber,
It heat-processed at 120 degreeC for 5 hours, stirring in a glass autoclave.

Excessive hydrochloric acid water was added to this under stirring at 100 rpm, and a rubber component was deposited and filtered. This is washed 3 times with 200 ml of water and at 50 ℃
The product was dried under reduced pressure in, and this was named prototype C.

In the same manner as in Example 1, the hot toluene insoluble content was obtained.

Further, Prototype C and a commercial acrylic rubber were mixed in the following formulation.

Except for this, the same test as in Example 1 was carried out.

The results are shown in Table 1 below.

Comparative Example 5. The ethylene-propylene rubber latex obtained in Reference Example 3 was impregnated with a mixture of 2.0 parts by weight of perhexa3M and 2.0 parts by weight of divinylbenzene per 100 parts by weight of the rubber content, and then in a glass autoclave. The mixture was heated at 120 ° C. for 5 hours with stirring.

Excessive hydrochloric acid water was added to this under stirring at 100 rpm, and a rubber component was deposited and filtered. This is washed 3 times with 200 ml of water and at 50 ℃
It was dried under reduced pressure in a sample, and this was named prototype D.

In the same manner as in Example 1, the hot toluene insoluble content was obtained.

Further, Prototype D and a commercial acrylic rubber were mixed in the following formulation.

Except for this, the same test as in Example 1 was carried out.

The results are shown in Table 1 below.

Example 5 100 parts by weight of the chlorinated ethylene / 1-butene copolymer rubber latex obtained in Reference Example 4 was impregnated with 2 parts by weight of divinylbenzene. The latex was crosslinked with an electron beam. That is, this latex was put into a container so that the thickness was 1.5 mm, the upper part of the container was sealed with a polyethylene film of 30 μ, and 20 Mrad was irradiated at an accelerating voltage of 750 KV.

Excessive hydrochloric acid water was added to this under stirring at 100 rpm, and a rubber component was deposited and filtered. This is washed 3 times with 200 ml of water and at 50 ℃
The product was dried under reduced pressure at, and this was named prototype E.

In the same manner as in Example 1, the hot toluene insoluble content was obtained.

Further, the trial product E and a commercially available acrylic rubber were mixed in the following formulation and used for the test.

The kneading was carried out for 20 minutes at 60 to 70 ° C. using an 8-inch open roll.

The dispersion state of the prototype E in the kneaded product was the same as in Example 1. Next, the kneaded material was press-vulcanized at 160 ° C for 20 minutes to obtain a thickness of 2 mm.
The vulcanized rubber sheet of was prepared and used for the measurement. The measurement was performed in the same manner as in Example 1.

The results are shown in Table 1 below.

Example 6 The formulation of Example 5 was as follows.

Except for this, the procedure was exactly the same as in Example 5.

The results are shown in Table 1 below.

Example 7 The formulation of Example 5 was as follows.

Except for this, the procedure was exactly the same as in Example 5.

The results are shown in Table 1 below. In Table 1, the * mark ()
The numbers inside indicate the amount of hot toluene insoluble matter (% by weight).

Continuation of front page (56) Reference JP-A-54-157152 (JP, A) JP-A-52-121654 (JP, A) JP-A-47-30751 (JP, A) JP-A-61-12711 (JP , A)

Claims (4)

[Claims] 1. A rubber composition comprising an acrylic rubber (A) and an ethylene / α-olefin copolymer rubber (B) in a weight ratio of A / B = 95/5 to 20/80. The ethylene
The α-olefin copolymer rubber (B) has an average particle size of 0.2 to 5
A vulcanizable acrylic rubber composition, which is a crosslinked rubber particle having a particle size of 0 μm and a hot toluene insoluble content of 30% by weight or more, and the crosslinked rubber particle is uniformly dispersed in the acrylic rubber. 2. A vulcanizable acrylic rubber according to claim 1, wherein the α-olefin of the ethylene / α-olefin copolymer rubber (B) contains 3 to 10 carbon atoms. Composition. 3. The vulcanizable acrylic rubber composition according to claim 1, wherein the ethylene / α-olefin copolymer rubber (B) contains a polyene component having a maximum iodine value of 30. 4. The vulcanizable composition according to claim 1, characterized in that the ethylene / α-olefin copolymer rubber (B) is modified with halogen and the halogen content is up to 40% by weight. Acrylic rubber composition.