JP2851939B2 - Ethylene-propylene-diene rubber, elastomer composition and vulcanized rubber thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ethylene-propylene-diene rubber, an elastomer composition and a vulcanized rubber thereof.

Technical Background of the Invention Ethylene-propylene-diene rubber (EPDM) is a rubber having excellent weather resistance, ozone resistance and heat aging resistance, and is used as a rubber for weather stripping, door glass run channel, radiator hose, etc. It is often used for parts.

On the other hand, almost all components requiring mechanical strength against dynamic fatigue, such as tires and vibration-isolating rubbers, use conjugated diene rubbers such as NR, SBR and BR, or blends thereof.

By the way, with the recent high performance of automobiles, improvement of heat aging resistance and weather resistance of automobile parts is desired.

However, although EPDM is excellent in weather resistance, ozone resistance and heat aging resistance, it has poor dynamic fatigue resistance,
EPDM could not be used alone for tires or engine mounts.

Japanese Patent Application Laid-Open No. 53-22551 discloses an ethylene-propylene rubber vibration-isolating rubber composition having an improved fatigue fracture life, which has an intrinsic viscosity [η] of 1.0 or less measured at 70 ° C. as a xylene solution. 10 to 50% by weight of a propylene-ethylidene norbornene terpolymer, 90 to 50% by weight of an ethylene-propylene-ethylidene norbornene terpolymer having an intrinsic viscosity [η] of 3.0 or more, and 100% of rubber Oil-extended rubber obtained by mixing 20 to 80 parts by weight of extender oil with respect to 100 parts by weight of rubber component, 5-90 parts by weight of carbon black and 0.1 to 2 parts by weight of sulfur per 100 parts by weight of rubber component. A vulcanizable rubber-isolated rubber composition characterized by adding a process oil to the rubber is disclosed.

However, simply high molecular weight ethylene-propylene-
The combination of the terpolymer of ethylidene norbornene and the terpolymer of low molecular weight ethylene-propylene-ethylidene norbornene alone cannot dramatically improve the dynamic fatigue resistance of existing EPDM.

Further, it is referred to Japanese Patent Publication No. Sho 51-30582 and Japanese Patent Publication No. Sho 52-777 that an excellent mechanical strength is imparted by knitting EPDM with sulfur. However, the inventions disclosed in these publications essentially require the addition of sulfur and a sulfur initiator, and the purpose is also specified only to provide EPDM excellent in co-vulcanizability with a highly unsaturated rubber. I have. Further, the degree of co-vulcanization is evaluated only by the tensile strength (Tb) after blending with the unsaturated rubber. On the other hand, whether or not dynamic fatigue resistance has been imparted can be evaluated only by conducting a fatigue test, and in that sense, these publications state that EPDM alone has excellent dynamic fatigue resistance.
Nothing has been suggested about DM. The invention disclosed in the above publication is a method for producing a co-vulcanizate of a low-unsaturated rubber and a highly unsaturated rubber, which is not a method for imparting dynamic fatigue resistance of EPDM, but a conjugated diene. It imparts heat resistance and ozone resistance while maintaining excellent dynamic fatigue resistance of the system rubber.

Further, as an example where dynamic fatigue resistance is most required, the use of high Mooney EPDM for A11-EPDM for a vibration-proof rubber material shows that its characteristics can be obtained. "Rubber Chemistry Technology, 44, 1971 Mon., p. 1043 ".

However, the use of high molecular weight EPDM is a matter of course for those skilled in the art, and the most important point of research and development is to improve physical properties without impairing processability. EPDM processability and high molecular weight are contradictory factors,
Means for achieving both of these have not been disclosed.

Therefore, it can withstand use under severe conditions where dynamic and mechanical durability is required, which has conventionally been considered impossible only with conjugated diene rubbers such as natural rubber and blends thereof, and is excellent. -Ethylene-propylene-diene rubber capable of imparting heat resistance, weather resistance and dynamic fatigue resistance, an elastomer composition containing the ethylene-propylene-diene rubber, and the appearance of a vulcanized rubber thereof are desired. Was.

Object of the Invention The present invention is intended for use under severe conditions where dynamic and mechanical durability is required, which has conventionally been considered impossible only with conjugated diene rubbers such as natural rubber and blends thereof. Ethylene-propylene-diene rubber capable of imparting excellent heat resistance, weather resistance and dynamic fatigue resistance, an elastomer composition containing the ethylene-propylene-diene rubber, and a vulcanized rubber thereof. It is intended to provide.

Summary of the Invention The ethylene-propylene-diene rubber according to the present invention has an ethylene content of 60 to 82 mol%, an intrinsic viscosity [η] of 3.0 to 5.0 dl / g measured in decalin at 135 ° C,
High-molecular-weight ethylene-propylene-diene copolymer rubber (A) having an iodine value of 8 to 35: 90 to 40% by weight, and an ethylene content of 60 to 82% by mole, and a limit measured at 135 ° C in decalin Viscosity [η] is 0.15 to 0.8 dl / g,
And a low molecular weight ethylene-propylene-diene copolymer rubber (B) having an iodine value of 8 to 35, consisting of 10 to 60% by weight, and having a Mooney viscosity ML _{1 + 4} (100 ° C.) of 60 to 120. In a certain ethylene-propylene-diene rubber, sulfur is present in a dispersed state, and ω _r (ω ₂ / ω) is an index of processability and physical properties obtained by a dynamic viscoelasticity test.
₁ ) is in the range of 50 to 150.

The vulcanizable elastomer composition according to the present invention has an ethylene content of 60 to 82 mol% and an intrinsic viscosity [η] of 3.0 to 5.0 dl / g measured in decalin at 135 ° C.
And a high molecular weight ethylene-propylene-diene copolymer rubber (A) having an iodine value of 8 to 35: 90 to 40% by weight, and an ethylene content of 60 to 82% by mole, and a limit measured in decalin at 135 ° C. Viscosity [η] is 0.15 to 0.8 dl / g,
And a low molecular weight ethylene-propylene-diene copolymer rubber (B) having an iodine value of 8 to 35, consisting of 10 to 60% by weight, and having a Mooney viscosity ML _{1 + 4} (100 ° C.) of 60 to 120. In a certain ethylene-propylene-diene rubber, sulfur is present in a dispersed state, and ω _r (ω ₂ / ω) is an index of processability and physical properties obtained by a dynamic viscoelasticity test.
₁ ) wherein ethylene-propylene- is in the range of 50 to 150;
It is characterized by containing a diene rubber.

Further, the vulcanized rubber according to the present invention is characterized by being obtained by vulcanizing the above-mentioned elastomer composition according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the ethylene-propylene-diene rubber, the elastomer composition, and the vulcanized rubber thereof according to the present invention will be specifically described.

The ethylene-propylene-diene rubber according to the present invention comprises a specific high molecular weight ethylene-propylene-diene copolymer rubber (A) and a specific low molecular weight ethylene-propylene-diene copolymer rubber (B). Of ethylene-propylene-diene rubber and sulfur.

Ethylene-propylene-diene rubber High molecular weight ethylene-propylene used in the present invention
The diene copolymer rubber (A) is composed of ethylene, propylene and a non-conjugated diene.

Specific examples of the non-conjugated diene include a chain non-conjugated diene such as 1,4-hexadiene, ethylidene norbornene (ENB), norbornadiene, methylene norbornene, dicyclopentediene, 2-methylnorbornadiene, and 5-vinyl. And cyclic non-conjugated dienes such as -2-norbornene. Among them, ENB is particularly preferably used.

The high molecular weight ethylene-propylene-diene copolymer rubber (A) used in the present invention has an iodine value of 8 to 35, preferably 10 to 30, which is an index of the non-conjugated diene content.

High molecular weight ethylene-propylene used in the present invention
The diene copolymer rubber (A) has an intrinsic viscosity [η] measured in decalin at 135 ° C. of 2.5 to 5.0 dl / g, preferably 3.0 to 5.0 dl / g.
4.3 dl / g and an ethylene content of 60-82 mol%. In particular, in applications that require a small change in vibration isolation characteristics from low to high temperatures, such as engine mounts, the ethylene content is preferably in the range of 60 to 72 mol%,
For applications used at room temperature or higher, high ethylene type EPDM with high mechanical strength, that is, ethylene content of 70 to
Preferably it is in the range of 80 mol%.

Low molecular weight ethylene-propylene used in the present invention
The diene copolymer rubber (B) is composed of ethylene, propylene and a non-conjugated diene. This non-conjugated diene is the same as the non-conjugated diene in the high molecular weight ethylene-propylene-diene copolymer rubber (A), and ENB is particularly preferably used.

Further, the iodine value of the low molecular weight ethylene-propylene-diene copolymer rubber (B) used in the present invention is also 8 to 35 as in the case of the high molecular weight ethylene-propylene-diene copolymer rubber (A). , Preferably 10 to 30.

In the present invention, high molecular weight ethylene-propylene-
As the difference in the non-conjugated diene content between the diene copolymer rubber (A) and the low molecular weight ethylene-propylene copolymer rubber (B), that is, the difference in iodine value, becomes larger, the vulcanization rate becomes more uneven, and the strength properties are increased. And the set such as compression set (CS) tend to have an adverse effect. Therefore, the iodine value of the low molecular weight ethylene-propylene-diene copolymer rubber (B) is as high as possible with the high molecular weight ethylene-propylene-diene copolymer. It is preferable to select the polymer rubber (A) so as to be the same as the iodine value of the polymer rubber (A).

The low molecular weight ethylene-propylene-diene copolymer rubber (B) used in the present invention has an intrinsic viscosity [η] of 0.15 to 0.8 dl / g, preferably 0.2 to 0.4 dl / g, measured at 135 ° C. in decalin. g and an ethylene content of 60 to 82 mol%. In particular, in applications that require a small change in vibration isolation characteristics from low to high temperatures, such as engine mounts, the ethylene content is preferably in the range of 60 to 72 mol%. High ethylene type EPDM with high mechanical strength, that is, ethylene content
Preferably it is in the range of 70-80 mol%.

When the intrinsic viscosity [η] becomes 0.15 dl / g or less, the properties of low molecular weight ethylene-propylene-diene copolymer rubber become equal to those of paraffinic or naphthenic softeners, so that mechanical strength and fatigue life are improved. No effect can be expected.

The high molecular weight ethylene-propylene-diene copolymer rubber (A) and the low molecular weight ethylene-propylene-
When the elastomer composition containing the ethylene-propylene-diene rubber comprising the diene copolymer rubber (B) is in an unvulcanized state, the low molecular weight ethylene-propylene-diene copolymer rubber (B) is To expand the molecular weight distribution of the ethylene-propylene-diene rubber, and to play the role of a softener, the elastomer composition according to the present invention is:
High strength and excellent dynamic fatigue resistance of the high molecular weight ethylene-propylene-diene copolymer rubber (A) can be maintained.

When the elastomer composition is in a vulcanized state,
Since the low molecular weight ethylene-propylene-diene copolymer rubber (B) is involved in vulcanization by itself, it has the effect of improving the rubber strength and increasing the dynamic fatigue resistance by the stress relaxation effect.

In the present invention, the high-molecular-weight ethylene-propylene-diene copolymer rubber (A) is composed of the high-molecular-weight ethylene-propylene-diene copolymer rubber (A) and the low-molecular-weight ethylene-propylene rubber.
It is used in an amount of 90 to 40% by weight, preferably 85 to 60% by weight based on 100% by weight of the total amount of the propylene-diene copolymer rubber (B), and comprises a low-molecular-weight ethylene-propylene-diene copolymer rubber ( B) is 10 to 60% by weight, preferably 15 to 40% by weight, based on 100% by weight of the total amount of the above (A) and (B).
It is used in amounts by weight.

The high molecular weight ethylene-propylene-diene copolymer rubber (A) and the low molecular weight ethylene-propylene-
The ethylene-propylene-diene rubber according to the present invention comprising the diene copolymer rubber (B) has a Mooney viscosity ML _{1 + 4} (100 ° C.) of 60 to 120, preferably 80 to 100.

The ethylene-propylene-diene rubber having a Mooney viscosity ML _{1 + 4} (100 ° C.) within the above range has good kneading properties with a Banbury mixer.

The present inventors have proposed a dynamic viscoelasticity test (strain rate 10%, temperature 190 ° C., sample table) to specify EPDM having excellent dynamic fatigue resistance.
Parallel plate, frequency; 1.58 × 10 ^-2 rad / S to 5 × 10 ² r
ad / S) in, the horizontal axis represents frequency and the vertical axis represents the complex modulus G ^*, G * ⁼ the corresponding frequency is omega ₂ to 1E6, also a frequency corresponding to G ^{* =} 1E5 as omega ₁ ω _r
= Ω ₂ / ω _1, and the index of ω _r is used to express the state of workability and physical properties of EPDM. This index ω _r
Affects the side chain and entanglement, composition distribution, and molecular weight distribution of EPDM. Therefore, by using this index, the state of processability and physical properties can be well expressed. The ethylene-propylene-diene rubber according to the present invention has an ω _r of 50 to 50.
Since it is within the range of 150, it is particularly excellent in the balance between kneading properties and physical properties. The ethylene-propylene-diene rubber having ω _r in the above range is not only excellent in kneading properties but also excellent in crack growth resistance and heat aging resistance. it can.

Sulfur In the present invention, sulfur is ethylene-propylene-
It exists in the diene rubber in a dispersed state.

That is, an ethylene-propylene-diene rubber obtained by simply combining the high molecular weight ethylene-propylene-diene copolymer rubber (A) and the low molecular weight ethylene-propylene-diene copolymer rubber (B) as described above. Even if (EPDM) is used, the elastomer composition excellent in dynamic fatigue resistance aimed at by the present invention cannot be obtained. However,
The effect of improving the dynamic fatigue resistance consisting of only the above combination is sufficiently recognized as compared with the oil-extended high molecular weight ethylene-propylene-diene copolymer rubber.
However, an EP consisting only of the above combinations
The elastomer composition using DM has remarkably inferior dynamic fatigue resistance as compared with a diene rubber such as natural rubber (NR).

Accordingly, the present inventors have conducted intensive studies and have found that an ethylene-propylene-diene-based rubber composed of a high-molecular-weight ethylene-propylene-diene copolymer rubber (A) and a low-molecular-weight ethylene-propylene-diene copolymer rubber (B) When sulfur is preliminarily dispersed in rubber and then an appropriate amount of carbon black, a softener and other fillers are blended and kneaded, an elastomer exhibiting excellent dynamic fatigue resistance far exceeding conventional knowledge. It has been found that a composition is obtained.

As a method of dispersing sulfur in the ethylene-propylene-diene rubber, for example, a method of adding sulfur to a solution-state ethylene-propylene-diene rubber and then removing the solvent, or a method of solid-state ethylene-propylene-diene There is a method of kneading sulfur into a system rubber using a kneader or an internal mixer. The temperature at which sulfur is dispersed is preferably in the range of 90 to 160 ° C, more preferably 110 to 150 ° C.

In the present invention, sulfur is 0.1 to 5 parts by weight, preferably 100 parts by weight of the ethylene-propylene-diene-based rubber.
Used in amounts of 0.3 to 3.0 parts by weight.

The elastomer composition according to the present invention contains the ethylene-propylene-diene rubber according to the present invention as described above, a softener, and further, an inorganic filler used in the production of a vulcanized rubber described below. A filler such as an agent may be included.

Production of vulcanized rubber In order to obtain a vulcanized rubber from the elastomer composition according to the present invention, an unvulcanized compounded rubber (elastomer composition) is prepared in the same manner as when vulcanizing a general rubber in the same manner as described below. It may be adjusted once, and then vulcanized after forming the compounded rubber into an intended shape.

When producing the vulcanized rubber according to the present invention, depending on the intended use of the vulcanized rubber, depending on the performance based thereon, in addition to the sulfur-containing ethylene-propylene-diene rubber, a softener, an inorganic filler and the like The type and amount of the filler, the type and amount of the vulcanization accelerator, and the step of producing the vulcanized rubber are appropriately selected.

As the softener, a softener used for rubber is usually used.Specifically, process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt,
Petroleum softeners such as petrolatum; coal tar softeners such as coal tar and coal tar pitch; fatty oil softeners such as castor oil, linseed oil, rapeseed oil, and coconut oil; tall oil;
Sub; waxes such as beeswax, carnauba wax, lanolin;
Ricinoleic acid, palmitic acid, barium stearate,
Fatty acids and fatty acid salts such as calcium stearate and zinc laurate; synthetic polymer substances such as petroleum resin, atactic polypropylene, and coumarone indene resin are used. Among them, petroleum softeners are preferably used,
Particularly, process oil is preferably used.

As the inorganic filler, specifically, SRF, GPF, FE
Carbon black such as F, HAF, ISAF, SAF, FT, MT, etc.
Examples include finely divided silica, light calcium carbonate, heavy calcium carbonate, talc, clay and the like. In the present invention, the inorganic filler is 20 to 150 parts by weight, preferably 30 to 100 parts by weight, more preferably 40 to 8 parts by weight, based on 100 parts by weight of the ethylene-propylene-diene rubber containing no sulfur.
Used in an amount of 0 parts by weight. By using the inorganic filler in an amount within the above range, an elastomer composition and a vulcanized rubber having excellent wear resistance and dynamic fatigue resistance can be obtained.

In the present invention, the combined use of a vulcanization accelerator is preferred. Specific examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole-sulfenamide, N-oxydiethylene-2-benzothiazole-sulfenamide, N, N
-Diisopropyl-2-benzothiazole-sulfenamide, 2-mercaptobenzothiazole, 2- (2,4
-Dinitrophenyl) mercaptobenzothiazole, 2
Thiazole compounds such as-(2,6-diethyl-4-morpholinothio) benzothiazole and dibenzothiazyl-disulfide; diphenylguanidine, triphenylguanidine, diorthotolylguanidine, orthotolyl by guanide, diphenylguanidine phthalate and the like Guanidine compounds; aldehyde-amine or aldehyde-ammonia compounds such as acetaldehyde-aniline reactant, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant; imidazoline compounds such as 2-mercaptoimidazoline; thiocarbanilide Thiourea-based compounds such as thiourea, diethylthiourea, dibutylthiourea, trimethylthiourea, and diorthotolylthiourea; tetramethylthiuram monosulfate De, tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, thiuram-based compounds such as pentamethylene thiuram tetrasulfide; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate,
Dithioacid salt compounds such as zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate and tellurium diethyldithiocarbamate; xanthates such as zinc dibutylxanthogenate Compounds: Other compounds such as zinc white are used.

The vulcanization accelerator is a sulfur-free ethylene-
0.1 to 20 with respect to 100 parts by weight of the propylene-diene rubber.
It is used in a ratio of 0.2 to 10 parts by weight, preferably 0.2 to 10 parts by weight.

The unvulcanized compounded rubber is prepared by the following method.
That is, using mixers such as a Banbury mixer, the ethylene-propylene-diene rubber according to the present invention, a softener, kneading the fillers such as inorganic fillers at a temperature of 80 to 170 ° C. for 3 to 10 minutes, Using a roll such as an open roll, if necessary, additionally mix a vulcanization accelerator, knead the mixture at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, extrude the kneaded product, and mix in a ribbon or sheet. Prepare rubber.

The compounded rubber thus prepared is molded into an intended shape by an extruder, a calender roll, or a press, and simultaneously with molding or by introducing a molded product into a vulcanization tank,
Heat at a temperature of 150 to 270 ° C for 1 to 30 minutes to obtain a vulcanized rubber. When performing such vulcanization, a mold may be used, or a mold may not be used. When a mold is not used, the steps of molding and vulcanization are usually performed continuously.

As a heating method in the vulcanizing tank, hot air, a fluidized bed of glass beads, UHF (ultra-high frequency electromagnetic wave), steam, or the like can be used.

EFFECT OF THE INVENTION The ethylene-propylene-diene rubber according to the present invention comprises a specific high molecular weight ethylene-propylene-diene copolymer rubber (A) and a specific low molecular weight ethylene-propylene-diene copolymer rubber (B). Include in a certain percentage,
A specific amount of sulfur is present in a dispersed state in ethylene-propylene-diene rubber having a Mooney viscosity ML _{1 + 4} (100 ° C.) in the range of 60 to 120, and ω _r (ω ₂ / ω ₁ ) Is 50
Because it is within the range of ~ 150, under the severe conditions where dynamic and mechanical durability is required, which has conventionally been considered impossible only with conjugated diene rubbers such as natural rubber and blends thereof. And has the effect of imparting excellent heat resistance, weather resistance and dynamic fatigue resistance.

Further, since the elastomer composition according to the present invention contains an ethylene-propylene-diene rubber having the above-described effects, conventionally, it is not a conjugated diene rubber such as natural rubber or a blend thereof. It has the effect of withstanding use under severe conditions requiring dynamic and mechanical durability, which has been considered impossible, and having excellent heat resistance, weather resistance and dynamic fatigue resistance. A vulcanized rubber having the following effects can be provided.

Further, the vulcanized rubber according to the present invention has a tensile strength (T _B ),
Since there is almost no variation in tensile elongation (E _B ) and little variation in fatigue test results, it also has the effect of stabilizing the quality required in actual product manufacturing.

Since the vulcanized rubber obtained from the elastomer composition according to the present invention has the above-described effects, it is widely used in applications such as tires, automobile parts, general industrial parts, and civil engineering building materials. In particular, muffler hangers, belts, anti-vibration rubbers, which have conventionally been considered to be usable only with diene rubbers, especially natural rubber or blends thereof,
It can be suitably used for engine mounts, pneumatic tire treads, pneumatic tire sidewalls, white sidewalls, and the like.

Hereinafter, the present invention will be described with reference to examples, the present invention,
It is not limited to these examples.

In addition, the evaluation test method of the vulcanized sheet in Examples and Comparative Examples is as follows.

(1) Tensile test A vulcanized rubber sheet was punched out to obtain a No. 3 type dumbbell test piece described in JIS K 6301.
K 6301 According to the method specified in paragraph 3, measurement temperature 25 ℃,
Tensile subjected to tensile test at a rate of 500 mm / min condition, the tensile stress at break T _B and tensile elongation at break E _B were measured.

(2) Heat aging resistance The heat aging resistance is measured in accordance with JIS K 6301-1975 6.5 in accordance with the following retention rates of stress at break, elongation at break, and JIS.
Evaluate the change in A hardness.

(I) A dumbbell No. 1 type tensile test piece of JIS K 6301 was punched out from the longitudinal direction of the sheet, the test piece was left at 120 ° C. for 72 hours, returned to room temperature, and subjected to a tensile test at a speed of 200 mm / min. Stress at break (T Baged) and Elongation at break (E
Baged) is measured. On the other hand, the stress at break (T Borig) and the elongation at break (E Borig) of the sample before thermal aging are measured in advance, and the retention of stress at break and the retention of elongation at break are calculated.

Retention of stress at break [%] = (T Baged / T Borig) x 1
00 Retention of elongation at break [%] = (E Baged / E Borig) x 1
00 (ii) Change in JIS A hardness (JIS K 6301) A _H = H ₂ −H ₁ where A _H is the change in JIS A hardness, H ₁ is the hardness before vulcanization, H
₁ indicates hardness after vulcanization.

(3) Crack growth due to bending (bending test) Crack growth due to bending was measured using a dematcher-type tester (300 rpm) according to ASTM D813.
Each of the books was repeatedly bent at a measurement temperature of 40 ° C. until the vulcanized rubber sheet was cut, and evaluated by the average value of the number of times of bending at the time of cutting.

(4) Durability test (Monsanto fatigue test) A vulcanized rubber sheet was punched out to obtain a No. 3 type dumbbell test piece described in JIS K 6301, and the elongation rate of each of the 20 test pieces was set to 20%, and measured. Temperature 40 ° C, rotation speed 30
Elongation fatigue was performed under the condition of 0 rpm, and the average value of the number of times of cutting the dumbbell was used as an index of durability.

(5) Exothermic test According to ASTM D 623, an exothermic test was performed using a Goodrich flexometer under the conditions of a load of 15 lb and a stroke of 6.9 mm, and the rising temperature (change temperature) T ₂ -T ₁ = ΔT was measured. The number of test pieces used for the measurement was two, and the experiment starting temperature was 37 ° C.

Example 1 70 mol% of a high-molecular-weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having an ethylene content of 70 mol%, an intrinsic viscosity [η] of 3.6 dl / g measured in decalin at 135 ° C., and an iodine value of 20 And ethylene content 70 mol%, 135
C., consisting of 30% by weight of a low molecular weight ethylene-propylene-5-ethylene-2-norbornene copolymer rubber having an intrinsic viscosity [η] of 0.24 dl / g and an iodine value of 20 measured in decalin.
Mooney viscosity ML _{1 + 4} (100 ° C) 82, ω _r 80 ethylene-propylene-diene rubber (hereinafter referred to as EPDM-1) 100
130 parts by weight with a kneader of 0.75 parts by weight of sulfur
The mixture was kneaded by adding a shear while applying heat at 3 ° C. for 3 minutes to disperse the sulfur.

Then, 1 part by weight of stearic acid, 5 parts by weight of zinc white No. 1 and FEF-HS carbon [Niteron # 1 manufactured by Nippon Steel Chemical Co., Ltd.] were added to an ethylene-propylene rubber in which sulfur was dispersed.
0] 60 parts by weight and oil [P-300, manufactured by Fujikosan Co., Ltd.]
10 parts by weight were kneaded with a 4.3-capacity Banbury mixer (manufactured by Kobe Steel Ltd.).

The kneaded product thus obtained was added to a 14-inch roll as a vulcanization accelerator, 1.5 parts by weight of Noxeller M (trade name, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and a trade name of Noxeller DM [Ouchi Shinko Chemical Co., Ltd. Co., Ltd.) and 0.5 parts by weight of Noxeller TT [Ouchi Shinko Chemical Co., Ltd.], mixing time on a roll is 4 minutes, and the surface temperature of the open roll is 50 ° C. on the front roll. After kneading under the conditions of 60 ° C. with the rear roll, the rotation speed of 16 rpm with the front roll, and 18 rpm with the rear roll,
The sheet was separated into pieces and pressed at 150 ° C. for 30 minutes to obtain a vulcanized sheet having a thickness of 2 mm. The vulcanized sheet was subjected to a tensile test, a heat aging test, a bending test, a durability test, and a heat generation test.

 Table 1 shows the results.

Comparative Example 1 Natural rubber (NR) [RSS 1] 70 parts by weight and styrene
30 parts by weight of butadiene rubber (SBR) [trade name: Tuffden 1530, manufactured by Asahi Kasei Corporation], 1 part by weight of stearic acid,
4.3 Banbury mixer with 5 parts by weight of Zinc Hua No.1, 50 parts by weight of FEF-HS carbon [Niteron # 10 manufactured by Nippon Steel Chemical Co., Ltd.] and 40 parts by weight of oil [P-300 manufactured by Fujikosan Co., Ltd.] (Made by Kobe Steel Ltd.).

To the kneaded material thus obtained, 1 part by weight of sulfur and a vulcanization accelerator [Noxeller, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.]
[CZ] was added and kneaded with a roll, then separated into sheets and pressed at 150 ° C. for 30 minutes to obtain a vulcanized sheet having a thickness of 2 mm, and the vulcanized sheet was evaluated.

 Table 1 shows the results.

Comparative Example 2 100 parts by weight of EPDM-1 of Example 1, 1 part by weight of stearic acid, 5 parts by weight of Zinc Hua No. 1, 50 parts by weight of FEF-HS carbon [Niteron # 10 manufactured by Nippon Steel Chemical Co., Ltd.] Oil [Fujikosan Co., Ltd., P-300] 10 parts by weight and capacity 4.3
The mixture was kneaded with a Banbury mixer (manufactured by Kobe Steel Ltd.).

To the kneaded material thus obtained, on a 14-inch roll, 0.75 parts by weight of sulfur, 1.5 parts by weight of Noxeller M (trade name, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) as a vulcanization accelerator, and 1.5 parts by weight and trade name Noxeller TT [Ouchi Shinko Chemical Co., Ltd.]
0.5 parts by weight, mixing time on a roll is 4 minutes, the surface temperature of the open roll is 50 ° C. on the front roll, 60 ° C. on the rear roll, the rotation speed is 16 rpm on the front roll, and 18 r on the rear roll.
After kneading under the condition of pm
After pressing for 2 minutes, a vulcanized sheet having a thickness of 2 mm was obtained, and the vulcanized sheet was evaluated.

 Table 1 shows the results.

Comparative Example 3 In Comparative Example 2, instead of EPDM-1 of Example 1,
High molecular weight ethylene-propylene-5 constituting EPDM-1
-Ethylidene-2-norbornene copolymer rubber (ω _r : 20
0), a vulcanized sheet having a thickness of 2 mm was obtained in the same manner as in Comparative Example 2 except that the blending amount of the oil was changed to 60 parts by weight.

 Table 1 shows the results.

Comparative Example 4 70% by weight of a high molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having an ethylene content of 70 mol%, an intrinsic viscosity [η] of 2.5 dl / g measured in decalin at 135 ° C., an iodine value of 20, and Ethylene content 70mol%, 135 ℃
100 weight parts of an ethylene-propylene-diene rubber comprising 30 weight% of a low molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having an intrinsic viscosity [η] of 0.3 dl / g and an iodine value of 20 measured in decalin. Part and sulfur 2.0
The mixture was kneaded with a weight part at 130 ° C. for 3 minutes using a kneader while applying heat to disperse sulfur.

Next, 1 part by weight of stearic acid, 5 parts by weight of zinc white No. 1 and 60 parts of FEF-HS carbon [Asahi Carbon Co., Ltd., 60 HG] were added to ethylene-propylene rubber in which sulfur was dispersed.
Parts by weight and 60 parts by weight of oil [P-300, manufactured by Fujikosan Co., Ltd.] were kneaded with a 4.3 Banbury mixer [manufactured by Kobe Steel Ltd.].

The kneaded material thus obtained was added to a 14-inch roll as a vulcanization accelerator, using 0.5 parts by weight of Noxeller M (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) and Noxeller TT (product name of Ouchi Shinko Chemical Industry Co., Ltd.) Co., Ltd.], adding 1.5 parts by weight, mixing time on a roll is 4 minutes, the surface temperature of the open roll is 50 ° C. on the front roll, 60 ° C. on the rear roll, and the rotation speed is 16 ° on the front roll.
After kneading at 18 rpm with a subsequent roll, the mixture is separated into sheets and pressed at 150 ° C. for 20 minutes to obtain a vulcanized sheet having a thickness of 2 mm. The vulcanized sheet is subjected to a tensile test and a hardness test (JIS A Hardness), a durability test, and a heat generation test.

Further, each of the above-mentioned compounds was put into a pressurized kneader (model TDI-5, manufactured by Toshin Sangyo Co., Ltd.), mixed under steam heating, and then the obtained mixture was rolled on a front roll (roll: Terakawa Seisakusho) , 8 ″ φ × 20 ″ L steam-heated water-cooled automatic temperature control type), and turned back and forth four times. One minute later, the roll workability of this mixture was evaluated. The distance between the front roll and the rear roll is 0.6 mm.

[Roll processability display method] E: Excellent (Excellent) G: Good (Good) F: Fair (Pair) P: Poor (Poor) VP: Very poor (Very Poor) [Display standard] 1) The kneaded material wound around the roll after the first turning is evaluated.

 Lower limit of E: There is no hole from the beginning.

Lower limit of G: Approximately 10 small holes within 2 to 5 mmφ
The number of holes around mφ is within several.

F lower limit: 50% or more of the portion connected on the roll surface.

P lower limit: Most of the kneaded material hangs, and only a part of the kneaded material is wrapped around the roll.

Upper limit of VP: The kneaded material will come off the roll without help.

2) The kneaded material wound around the roll after the second, third, and fourth turning is evaluated.

Lower limit of E: No tendency for bagging is observed. There is perfect adhesion.

Lower limit of G: Apparently, the kneaded material does not come into close contact with the roll, but is partially wavy at the upper part of the roll.

Even if bagging occurs due to a slip or the like, it recovers on its own, but it is duplicated by one correction of human power.

Lower limit of F: On the outer peripheral surface of the lower half of the front roll,
The kneaded material is in close contact, but when passing through the outer peripheral surface, the adhesiveness of the kneaded material is poor in the range up to the upper part of the roll, and the material is partially wavy.

Lower limit of P: Bagging occurs, but correction is sometimes made to prevent the kneaded material from hanging from the roll.

Upper limit of VP: Bagging occurs, and the kneaded material hangs down from the roll unless it is constantly corrected.

 Table 2 shows the above results.

Examples 2 and 3 In Comparative Example 4, instead of the high-molecular-weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber of Comparative Example 4, an intrinsic viscosity measured in decalin at 135 ° C and an ethylene content of 70 mol% was used. [Η] 3.0 dl / g, high molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having an iodine value of 20, ethylene content 70 mol%, intrinsic viscosity [η] 4.6 dl measured in decalin at 135 ° C. / g, a high molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having an iodine value of 20 was used in Examples 2 and 3, respectively, except that
A vulcanized sheet having a thickness of 2 mm was obtained in the same manner as in Comparative Example 4, and the vulcanized sheet was evaluated.

 Table 2 shows the results.

Comparative Example 5 In Comparative Example 4, instead of the high-molecular-weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber of Comparative Example 4, an intrinsic viscosity [η] measured in decalin at 135 ° C. and 70 mol% of ethylene was used. ] A thickness of 2 m was obtained in the same manner as in Comparative Example 4 except that a high molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having 5.2 dl / g and an iodine value of 20 was used.
m was obtained, and this vulcanized sheet was evaluated.

 Table 2 shows the results.

Comparative Examples 6 and 7 In Comparative Example 4, instead of the high-molecular-weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber of Comparative Example 4, an intrinsic viscosity measured in decalin at 135 ° C and an ethylene content of 70 mol% was used. [Η] 4.6 dl / g, high molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber having an iodine value of 20, and low-molecular-weight ethylene-propylene-5 of Comparative Example 4
Instead of the ethylidene-2-norbornene copolymer rubber, a low molecular weight ethylene-propylene-5-ethylidene having an ethylene content of 70 mol%, an intrinsic viscosity [η] of 0.10 dl / g measured in decalin at 135 ° C., and an iodine value of 20 was used. 2-norbornene copolymer rubber, low molecular weight ethylene-propylene-5-ethylidene-2-norbornene copolymer having an ethylene content of 70 mol%, an intrinsic viscosity [η] of 1.0 dl / g measured in decalin at 135 ° C., and an iodine value of 20 Except that the united rubber was used in Comparative Examples 6 and 7, respectively,
A vulcanized sheet having a thickness of 2 mm was obtained in the same manner as in Comparative Example 4, and the vulcanized sheet was evaluated.

 Table 2 shows the results.

Claims (3)

(57) [Claims] (1) an ethylene content of 60 to 82 mol%,
The intrinsic viscosity [η] measured in decalin at 3.0 ° C is 3.0 to 5.0 dl / g
High molecular weight ethylene-propylene-diene copolymer rubber (A) having an iodine value of 8 to 35 and 90 to 40% by weight, and having an ethylene content of 60 to 82% by mole at 135 ° C in decalin A low molecular weight ethylene-propylene-diene copolymer rubber (B) having a measured intrinsic viscosity [η] of 0.15 to 0.8 dl / g and an iodine value of 8 to 35: 10 to 60% by weight; Sulfur is present in a dispersed state in an ethylene-propylene-diene rubber having a viscosity ML _{1 + 4} (100 ° C) in the range of 60 to 120, and the processability is determined by a dynamic viscoelasticity test. And ω _r (ω ₂ /
ω ₁ ) is in the range of 50 to 150, an ethylene-propylene-diene rubber. 2. The method according to claim 1, wherein the ethylene content is 60 to 82 mol%,
The intrinsic viscosity [η] measured in decalin at 3.0 ° C is 3.0 to 5.0 dl / g
High molecular weight ethylene-propylene-diene copolymer rubber (A) having an iodine value of 8 to 35 and 90 to 40% by weight, and having an ethylene content of 60 to 82% by mole at 135 ° C in decalin A low molecular weight ethylene-propylene-diene copolymer rubber (B) having a measured intrinsic viscosity [η] of 0.15 to 0.8 dl / g and an iodine value of 8 to 35: 10 to 60% by weight; Sulfur is present in a dispersed state in an ethylene-propylene-diene rubber having a viscosity ML _{1 + 4} (100 ° C) in the range of 60 to 120, and the processability is determined by a dynamic viscoelasticity test. And ω _r (ω ₂ /
A vulcanizable elastomer composition containing an ethylene-propylene-diene rubber having an ω ₁ ) in the range of 50 to 150. 3. A vulcanized rubber obtained by vulcanizing the elastomer composition according to claim 2.