JP2639395B2 - Rubber composition and method for producing rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention comprises ethylene-propylene-diolefin copolymer rubber (hereinafter referred to as EPDM rubber) as a main component, and has crack resistance as well as weather resistance and heat resistance. The present invention relates to a rubber composition having excellent heat resistance and abrasion resistance, and a method for producing the rubber composition.

[Prior art] EPDM rubber has essentially no double bond in the main chain, and therefore has essentially excellent weather resistance and heat resistance. Various studies have been conducted to utilize this property in tires. Has been done. For example, when this rubber is used for tire sidewalls, its excellent weather resistance makes it possible to reduce the amount of amine anti-aging agents and paraffin waxes that have been used to ensure weather resistance, and in some cases it may become unnecessary. There is. However, this EPDM rubber is certainly excellent in weather resistance and heat resistance, but on the other hand, its breaking strength and flex durability are several orders of magnitude lower than diene rubber, and amine-based antioxidants are added to diene rubber. It was thought that the combination was more effective.

Japanese Patent Application Laid-Open No. Sho 62-148543 discloses that, with the aim of improving the vulcanization adhesiveness of EPDM rubber with an adjacent rubber, at least one highly unsaturated rubber-like polymer is bonded as the sole polymer elastomer component. Conjugated diene content about 6 to about 15% by weight (EP
(Relative to DM) high molecular weight EPDM polymer, and the EPDM polymer is about 25 to 100 parts by weight of the total elastomer.
About 50 parts by weight, the EPDM polymer having a Mooney viscosity ((ML _{1 + 8} 100 ° C.)) greater than about 150 and a rubber composition having an ethylene / propylene weight ratio of about 50/50 to about 75/25. It has been disclosed.

However, in terms of improving breaking strength and bending resistance,
There is still room for improvement.

[Problems to be Solved by the Invention] The present invention controls the microstructure of EPDM rubber, which is a non-diene rubber, so that the iodine value does not increase extremely and the conventional EPDM rubber composition can be compared with a conventional EPDM rubber composition, and crack growth resistance can be improved. It is intended to provide a rubber composition having significantly improved properties and abrasion resistance.Moreover, upon producing this rubber composition,
It is an object of the present invention to provide a technique for preventing a filler, particularly carbon black or silicon dioxide, used in a blend with a rubber from being unevenly distributed toward a diene rubber and causing a significant decrease in physical properties.

[Means for Solving the Problems] In the present invention, the rubber components are diene rubber, rubber and ethylene-
A rubber composition comprising a propylene-diolefin copolymer rubber and containing an inorganic filler in an amount of 20 to 200 parts by weight based on 100 parts by weight of a rubber component, wherein the ethylene-propylene-diolefin copolymer has A . Glass transition temperature Tg (measured by DSC) ≤ -40 ° C B. Iodine value = 10 to 34 C. 220,000 ≤ weight average molecular weight ≤ 600,000 D. Ethylene content = 68 to 85 mol% E. 2.0 ≤ molecular weight distribution (M _w / M _n ) <3.0 F.95 ≦ 1.5 × (iodine value) + (ethylene content) ≦ 120 G.90 ≦ (weight average molecular weight) × 10 ⁻⁴ + (ethylene content)
Satisfies all conditions of ≦ 160 and the content is 100
A vulcanizable rubber composition characterized by being 20 to 80 parts by weight based on parts by weight, and further producing this rubber composition, particularly a blend rubber composition of EPDM rubber and diene rubber. At this time, 10-100 parts per 100 parts by weight of EPDM rubber in advance
This is a method for producing a rubber composition, which comprises blending parts by weight of an inorganic filler, particularly carbon black or silicon dioxide.

In the present invention, the EPDM rubber is limited to 20 to 80 parts by weight,
If the amount is less than 20 parts by weight, sufficient weather resistance and heat deterioration resistance cannot be obtained. Although the reason is not clear, the EPDM rubber of the present invention is 26-30 as the blend amount is increased.
There is a characteristic that the weather resistance and the heat deterioration resistance are rapidly improved from about parts by weight, and preferably 30 parts by weight or more. The upper limit is 80 parts by weight, as shown in Example 11 described later. If the upper limit is exceeded, the vulcanization adhesion to other members is inferior and an undesirable situation appears in this respect. If the amount of the inorganic filler is less than 20 parts by weight, the breaking strength (strength at break, elongation at break) of the rubber composition after vulcanization is not sufficient, and if it is more than 200 parts by weight, the uncured Workability cannot be sufficiently obtained.

The reason for limiting the glass transition temperature of the EPDM rubber at −40 ° C. or lower when measured at a heating rate of 10 ° C./min by DSC is −40 ° C.
If the temperature is higher than ℃, sufficient crack growth resistance and bending durability cannot be obtained. The iodine value is limited to 10 to 34, because if it is smaller than 10, sufficient co-vulcanization with diene rubber, crack growth resistance, strength at break, elongation at break cannot be obtained, 34 If it is larger than the above, the synergistic effect of significantly improving the crack growth resistance, the strength at break, and the elongation at break cannot be achieved, and the wear resistance after thermal deterioration is also reduced, which is not preferable. In addition, the third component copolymerized to increase the iodine value is generally expensive, and as a rubber composition used for rubber products, the amount of the diolefin component is suppressed as much as possible, and the rubber with the best performance among them is used. Manufacturing is also an essential issue of EPDM rubber.

The reason why the weight average molecular weight of the EPDM rubber is limited to 220,000 to 600,000 is that the effect of improving crack growth resistance and abrasion resistance is remarkable at a molecular weight of 220,000 or more, and surprisingly, adhesion to diene rubber. This is because the strength is also greatly improved. However, as the molecular weight increases, the viscosity increases sharply,
There is the disadvantage that the processability during unvulcanization is also significantly reduced. Therefore, the region where the weight average molecular weight exceeds 240,000 is preferably oil-extended. Also, the weight average molecular weight
If it exceeds 600,000, the amount of oil required for workability is excessively increased, and physical properties after vulcanization, such as abrasion resistance, are unpreferably decreased. Paraffinic oil is preferred as the oil type for oil extension.

The reason that the ethylene content of the rubber containing ethylene-propylene as a main component was limited to 68 to 85 mol% is that if there is no ethylene content in this range, sufficient crack growth resistance, strength at break, and elongation at break are obtained. Because it cannot be obtained. More specifically, when the ethylene content is lower than 68 mol%, even when the iodine value is 10 or more, the effect of improving crack growth resistance, strength at break, and elongation at break is extremely small, and is 85 mol%. If it is higher than that, it is close to a polyethylene resin, the elongation at break is small, and the elastic modulus is also high, so that it is difficult to use the rubber industrially.

In the present invention, the molecular weight distribution ( _Mw / _Mn ) of the EPDM rubber is 2.
The reason for limiting to 0 or more is that if the molecular weight distribution (M _w / M _n ) is lower than 2.0, roll workability is poor and industrial use is difficult.

The molecular weight distribution ( _Mw / _Mn ) is preferably less than 3.0 in order to reduce the low molecular weight components of EPDM and improve the physical properties.

Also, "1.5 x (iodine value) + (ethylene content)"
If it is less than 9.5, sufficient crack growth resistance, strength at break, and elongation at break cannot be obtained, and if it exceeds 120, heat deterioration resistance (including abrasion resistance after heat deterioration) is reduced.

"(Weight average molecular weight) x ^10-4 + (ethylene content)"
If it is smaller than 90, the co-vulcanizability with the diene rubber and the crack growth resistance cannot be sufficiently obtained, and if it exceeds 160, the processability (dispersion of carbon black (C / B), roll workability) will increase. This is because not only does the rubber composition deteriorate, but also the modulus of elasticity of the rubber composition becomes too high, making it difficult to use it industrially.

As described above, the reasons for the individual limiting conditions can be explained, and all of these reasons are such that the EPDM rubber properties are satisfied within the range specified in the claims. In other words, it means that the effects of the present invention cannot be obtained unless all the conditions A to G are simultaneously satisfied. This is because there are some previously unknown synergistic effects between each condition.

In order to obtain the EPDM rubber in the present invention, there is also a method of making a blend of several EPDM rubbers, but it certainly shows considerably good physical properties and naturally belongs to the category of the present invention, but it is polymerized from the beginning by polymerization. A rubber composition using a rubber that satisfies the conditions described in the claims at one time shows superior physical properties (crack growth resistance, abrasion resistance, strength at break, elongation at break, etc.).

In the present invention, the diolefin component of the EPDM of the present invention is preferably ethylidene norbornene, which is more resistant to crack growth than other commonly used diolefin components such as dicyclopentadiene and 1,4-hexadiene. This is because better effects of improving properties, strength at break, and elongation at break can be expected.

In the present invention, the oil-extended amount of the ethylene-propylene-based rubber of the present invention is preferably 40 parts by weight or more, which is preferably a weight average molecular weight in order to sufficiently exert the effects of the present invention. If the oil extension amount is not more than 40 parts by weight, the workability is poor and it is difficult to industrially use the oil.

The rubber component other than EPDM is at least one rubber selected from the group of diene rubbers, and specific examples thereof include natural rubber, cis polybutadiene rubber, emulsion polymerization type or solution polymerization type SBR, and the like.

As the rubber composition of the present invention, the isoprene-based rubber is preferably contained in the diene-based rubber in an amount of 10 parts by weight or more, more preferably 20 parts by weight or more.
If the amount is less than the weight part, the kneading workability is reduced, and it is difficult to obtain sufficient physical properties at the time of vulcanized rubber depending on the compounding formulation. Also, from the viewpoint of securing the strength at break, it is industrially more efficient to use an appropriate amount of isoprene-based rubber than to use other diene-based rubber alone. Here, the isoprene-based rubber refers to natural rubber or synthetic polyisoprene rubber.

As the inorganic filler to be used as the rubber composition of the present invention, carbon black is most suitable. In addition, silicon dioxide (silica), calcium carbonate, titanium dioxide, white luster and the like can be used.

In the method for producing the rubber composition of the present invention, the amount of the inorganic filler of 10 to 100 parts by weight per 100 parts by weight of EPDM rubber is defined as follows: after EPDM polymerization, after adding the inorganic filler, the solvent is removed. ,dry. A so-called wet masterbatch may be used, but it is preferable to previously knead the inorganic filler with EPDM rubber using a kneader such as a Banbury mixer.

The amount of inorganic filler, especially carbon black, is
20 to 200 parts by weight per 0 parts by weight is preferred. If the amount is less than 20 parts by weight, the breaking strength of the rubber vulcanizate, that is, the strength at break or the elongation at break, is insufficient, and if it is more than 200 parts by weight, the workability in the unvulcanized state is sufficient. Because it cannot be taken.

In the method of adding carbon black, the concentration of the carbon black kneaded in the EPDM rubber beforehand with the rubber composition such as a tire sidewall that emphasizes weather resistance and flex durability is finally increased in the rubber composition. Is preferably lower than the concentration of carbon black.

Also, for rubber compositions such as Tight Red that emphasize wear resistance, the concentration of carbon black kneaded in EPDM rubber in advance may be higher than the concentration of carbon black in the rubber composition in the end. preferable.

In the structure of carbon black, a rubber composition that emphasizes abrasion resistance, such as a tire tread,
It is preferable that the amount of iodine adsorbed by the carbon black previously kneaded into the EPDM rubber is larger than that of the carbon black added later.

On the other hand, for rubber compositions that place importance on weather resistance and flex durability, such as tire sidewalls, the amount of iodine adsorbed by carbon black that is previously kneaded into EPDM rubber is smaller than that of carbon black added later. Is preferred.

As carbon black for the rubber composition constituting the sidewall portion of the present invention, iodine adsorption amount 35 ~ 100m
g / g, DBP oil absorption of 70 to 140 ml / 100 g is preferable.However, if the iodine adsorption is lower than 35 mg / g, it becomes difficult to obtain the desired strength at break, and conversely, 100 mg / g. If it exceeds, the bending durability decreases. DBP oil absorption 70ml / 10
If it is less than 0 g, the dispersion of carbon black will not be sufficient, and if it is more than 140 ml / 100 g, the hardness after vulcanization will be too large and the flex durability will be reduced.

As the carbon black of the rubber composition constituting the tread portion of the present invention, an iodine adsorption amount of 85 to 200 mg / g, DBP
Those having an oil absorption of 100 to 180 ml / 100 g are preferred. In order to ensure abrasion resistance, the iodine adsorption amount is preferably 85 mg / g or more, and the DBP oil absorption amount is preferably 100 ml / 100 g or more.In order to ensure dispersion of the carbon black in the rubber composition, the iodine adsorption amount is 200 mg. / g or less, and a DBP oil absorption of 180 ml / 100 g or less.

The rubber composition of the present invention does not require an amine anti-aging agent or a paraffin wax because it is overwhelmingly excellent in weather resistance and heat resistance as compared with commonly used diene rubber compositions. If the amount of EPDM rubber used is small,
For example, in the case of 20 parts by weight, a small amount may be added. Even so, if it is an amine antioxidant, it will be 0.
It is preferable to use 3 parts by weight or less, and 0.5 parts by weight or less in the case of paraffin wax. Of course, both may be used in combination.

When the rubber composition of the present invention is used for a sidewall portion of a tire, when the rubber composition has a hardness (JIS spring type hardness [A type]) of 30 to 60, the sidewall portion undergoes constant strain deformation. This is more preferable in terms of bending durability and crack growth resistance. When the rubber composition of the present invention is used for a tread portion of a tire, the hardness of the rubber composition (JIS
More preferably, the spring type hardness (A type) is set to 55 to 70. If it is less than 55, the steering stability and crack growth resistance of the tire will decrease, and if it exceeds 70, not only will the rib tread resistance and flex durability of the tire tread decrease, but also the grip performance will decrease, and sufficient This is because it becomes difficult to secure the braking performance.

Next, a method for producing the EPDM rubber used in the present invention will be described.

EPDM rubber in the present invention, for example, in a hydrocarbon solvent,
(A) a soluble vanadium compound [VO (OR) _n X _3-n : R is a hydrocarbon, X is a halogen, 0 ≦ n ≦ 3] or a vanadium compound represented by VX ₄ , (b) R ′ _m AlX ′ _{3 -m} [R 'is a hydrocarbon, X' is a halogen, 0≤m≤3] In the presence of a catalyst formed from an organoaluminum compound represented by the formula: ethylene, propylene and, for example, ethylidene norbornene as the third component The composition may be adjusted so as to obtain a desired composition and then random copolymerized.

Specific examples of the vanadium compound represented by the above general formula include the following.

VO (OCH ₃ ) Cl ₂ , VO (OCH ₃ ) ₂ Cl, VO (OCH ₃ ) ₃ , VO (OC ₂ H ₅ ) Cl
_{2, VO (OC 2 H 5} ) 2 Cl, VO (OC 2 H 5) 3, VO (OC 2 H 5) 1.5 Br 1.5, VO
(OCH ₃ H ₇ ) Cl ₂ , VO (OC ₃ H ₇ ) _1.5 Cl _1.5 , VO (OC ₃ H ₇ ) ₂ Cl, VO (O
_{C 3 H 7) 3, VO} (O -n- C 4 H 9) Cl 2, VO (O -n- C 4 H 9) 2 Cl, VO (O
_{-iso- C 4 H 9) Cl 2} , VO (O -sec- C 4 H 9) 3, VO (OC 5 H 11) 1.5 C
l _1.5 , VOCl ₃ , VCl ₄ or a mixture thereof. Among these, VO (OC ₂ H ₅ ) Cl ₂ and VOCL ₃ are particularly preferred.

Further, specific examples of the organoaluminum compound include the following.

(CH ₃ ) ₂ ) AlCl, (CH ₃ ) _1.5 AlCl _1.5 , (CH ₃ ) AlCl ₂ , (C ₂ H ₅ )
₂ AlCl, (C ₂ H ₅ ) _1.5 AlCl _1.5 , (C ₂ H ₅ ) AlCl ₂ , (C ₃ H ₇ ) ₂ AlC
l, (C ₃ H ₇ ) _1.5 AlCl _1.5 , (C ₃ H ₇ ) AlCl ₂ , (C ₆ H ₁₃ ) _1.5 AlCl
_1.5 , (C ₆ H ₁₃ ) Al ₂ Cl, (C ₆ H ₁₃ ) AlC ₁₂ , or a mixture thereof.

The usage ratio of the organic aluminum and the vanadium compound is
Al / V (atomic ratio) is preferably in the range of 2 to 50, particularly 5 to 30.

The copolymerization can be performed in a hydrocarbon solvent. For example, aliphatic hydrocarbons such as hexane, heptane, octane and kerosene, and aromatic hydrocarbons such as benzene, toluene and xylene can be used alone or in combination as a solvent.

In the copolymerization, the vanadium compound is contained in the reaction medium in an amount of 0.01 to 5%.
Mmol / l, preferably 0.1 to 2 mmol / l.

The ethylene content can be varied by controlling the amount supplied during the copolymerization, but it is industrially difficult to increase the ethylene content to 85 mol% or more. (From a laboratory perspective, the yield can be reduced.) The polymerization temperature is 0 to 100 ° C, preferably 20 to 80 ° C, and the polymerization pressure is maintained at 0 to 50 kg / cm ² . Hydrogen is used to control the molecular weight of the EPDM rubber produced.

[Example] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples unless it exceeds the gist of the present invention.

Production Example The rubber containing ethylene-propylene as a main component in the present invention was produced as follows.

Using a 15-liter stainless steel polymerization vessel equipped with a stirrer, ethylene, propylene and ethylidene norbornene were continuously copolymerized.

Hexane was continuously supplied as a polymerization solvent from the upper part of the polymerization vessel at a rate of 5 liters / hour. On the other hand, the polymerization liquid was withdrawn from the lower part of the polymerization vessel so that the polymerization liquid in the polymerization vessel was always 5 liters. As a catalyst, (a) VO (OC ₂ H ₅ ) Cl ₂ was used.
(B) (C ₂ H ₅ ) _1.5 AlCl _1.5 was continuously introduced from the top of the polymerization vessel into the polymerization vessel so that the aluminum atom concentration in the polymerization vessel was 1.70 mmol / L so that the concentration became 0.22 mmol / L. Supplied. Also, a mixed gas of ethylene and propylene (ethylene 45
Mol%. Propylene 55 mol%) at a rate of 450 liters per hour,
Feed at g rate. Hydrogen gas was supplied as a molecular weight regulator at a rate of 2.5 liters per hour.

The polymerization temperature was controlled at 45 ° C. by a jacket attached outside the polymerization vessel. The pressure inside the polymerization vessel is 4.8k
g / cm ² .

The polymerization liquid taken out from the lower part of the polymerization vessel was subjected to steam stripping, dried at 80 ° C. for 24 hours, and finally vacuum-dried. EPDM rubber was obtained at a rate of 285 g / h.

The weight average molecular weight _Mw and molecular distribution _Mw / _Mn were measured by the GPC method. The weight average molecular weight was determined in terms of polystyrene. The obtained sample was designated as Prototype-1.
Prototypes 2 to 8 were also produced by appropriately changing the third component amount, the catalyst amount ratio, the polymerization temperature or the polymerization time, and the like.

After the polymerization reaction was completed, a predetermined amount of paraffinic oil manufactured by Idemitsu Petrochemical Co., Ltd. was mixed in the prototypes 1 to 3 and 5 to 8 before steam stripping to obtain an oil-extended rubber.

Table 1 shows the details of the obtained EPDM rubber samples and the amount of oil-extended oil (parts by weight of oil-extended oil relative to 100 parts by weight of rubber).

Hereinafter, the present invention will be described more specifically with reference to examples.

First, the test method used and the EPDM rubber will be described.

<Test method> (1) Crack growth resistance A crack of 0.3 mm was placed in the center of a test piece of 60 mm x 100 mm x 1.0 mm, and an elongation strain was given under the conditions of a frequency of 300 cycles / minute and a strain of 50%, and this crack was given. The time required for the to grow to 20 mm was measured and evaluated by the following formula.

The larger the value, the better the crack growth resistance.

(2) Abrasion resistance (after heat treatment) The ratio of the amount of wear between the original sample and the sample left (heat treated) in a thermostat at 120 ° C. for 24 hours was determined, and the ratio was evaluated based on the following formula. The wear test was performed by Akron Wear ロ ン British Standard 903 Part A9 (1957),
The test was performed according to a load of 6 lbs, an angle of 15 °, and a main shearing of 1000 times.

However, The larger the value of the wear resistance, the better the wear resistance.

(3) Heat-resistant deterioration test piece: The strength ratio at break between the original sample of a 150 mm x 150 mm x 2.0 mm vulcanized rubber sheet and the sample left (heat-treated) in a thermostat at 120 ° C for 24 hours was determined. Based on the following formula, evaluation was made.

However, The larger the value is, the better the heat deterioration resistance is.

(4) Strength at break and elongation at break; Sample shape was measured using JIS No. 3 according to JIS K6301.

(5) Weather resistance Test piece 20mm x 100mm x 1.0mm rubber plate 50% in length direction
It was left in a constant temperature bath of elongation, 40 ° C. and ozone concentration of 50 pphm, and the time until cracks could be confirmed with the naked eye was determined and evaluated by the following equation.

The larger the value, the better the weather resistance.

[Examples 1 and 2, Comparative Examples 1 to 3] This Example and Comparative Example are comparisons between the EPDM rubber having a specific structure of the present invention and a conventional diene rubber and an EPDM rubber not satisfying the structure. The results are shown in Table 2. From the results shown in Table 2, the EPDM rubber of the present invention has, in addition to weather resistance and heat resistance,
It can be seen that the composition has extremely excellent crack growth resistance.

[Examples 1, 3 to 4, Comparative Example 1] In Examples and Comparative Examples, a method of using an EPDM rubber in which carbon black was previously kneaded in preparing an EPDM rubber composition (master batch method) and a conventional method were used. The results are shown in Table 3 in comparison with the method. From the results shown in Table 3, it can be seen that this masterbatch method has a remarkable improvement effect on crack growth resistance, heat deterioration resistance, strength at break, elongation at break and wear resistance.

[Examples 5 to 8, Comparative Examples 4 to 7] In the examples and comparative examples, the production of the present invention in the rubber composition production method (master batch method) of the present invention in which carbon black is kneaded in advance with EPDM rubber. The effect of the method was examined.

Table 4 shows the results. Table 4 shows that in this masterbatch method also, it is necessary for the EPDM rubber used to satisfy all the structural conditions of A to G in order to obtain excellent physical properties.

[Examples 9 to 11, Comparative Examples 8 to 9] In these examples and comparative examples, the amounts of EPDM rubber were examined. The results are shown in Table 5. From Table 5, it can be seen that the amount of EPDM is required to be 20 parts by weight or more to exhibit the characteristics.

[Examples 12 to 13 and Comparative Examples 10 to 12] In Examples and Comparative Examples, the amounts of carbon black were examined. The results are shown in Table 6. The results in Table 6 show that the amount is limited to the range of 20 to 200 parts by weight.

[Effect of the Invention] As shown in the above examples, the requirements A to G of EPDM rubber
The rubber composition of the present invention, which satisfies all of the above conditions, makes a great leap in the rubber composition using conventional EPDM rubber, in terms of crack growth resistance, abrasion resistance, strength at break, elongation at break, and even adhesion to diene rubber. It is clear that the improvement has been made.

Furthermore, the EPDM rubber composition satisfying the structural requirements A to G described in the claims is kneaded with carbon black in advance (master batch method) to prepare an EPDM rubber composition. In addition to the weather resistance and heat resistance of the rubber, breakage strength, bending durability, crack growth resistance and wear resistance, which have been regarded as disadvantages, have been dramatically improved.

The use of the rubber composition of the present invention in a tire sidewall dramatically improves the appearance, and the use in a tire tread significantly improves the appearance and groove crack resistance, and also significantly improves the rehabilitation life of large tires. I got it. The rubber composition of the present invention can be used not only for tires but also for general rubber products, for example, tires, industrial belts, hoses, anti-vibration rubbers, and fenders.

Claims (16)

(57) [Claims] 1. A rubber composition wherein the rubber component comprises a diene rubber and an ethylene-propylene-diolefin copolymer rubber and contains 20 to 200 parts by weight of an inorganic filler based on 100 parts by weight of the rubber component. The ethylene-propylene-diolefin copolymer has the following properties: A. Glass transition temperature Tg (measured by DSC) ≦ −40 ° C. B. Iodine value = 10 to 34 C.220,000 ≦ Weight average molecular weight ≦ 600,000 D. Ethylene Content = 68-85 mol% E.2.0 ≦ Molecular weight distribution ( _Mw / _Mn ) <3.0 F.95 ≦ 1.5x (Iodine value) + (Ethylene content) ≦ 120 G.90 ≦ (Weight average molecular weight) x10 ^-4 + (ethylene content)
Satisfies all conditions of ≦ 160 and the content is 100
A vulcanizable rubber composition characterized by being 20 to 80 parts by weight based on parts by weight. 2. The rubber composition according to claim 1, wherein the amount of the ethylene-propylene-diolefin copolymer rubber is at least 30 parts by weight. 3. The rubber composition according to claim 1, wherein the diolefin component of the ethylene-propylene-diolefin copolymer rubber is ethylidene norbornene. 4. The rubber composition according to claim 1, wherein the ethylene-propylene-diolefin copolymer rubber is an oil-extended rubber. 5. The rubber composition according to claim 1, wherein the diene rubber contains at least 10 parts by weight of an isoprene rubber. 6. The rubber composition according to claim 1, wherein the diene rubber contains at least 20 parts by weight of the isoprene rubber. 7. The rubber composition according to claim 4, wherein the oil used for oil extension is paraffinic oil. 8. The rubber composition according to claim 4, wherein the oil extension amount is 20 parts by weight or more. 9. The rubber composition according to claim 1, wherein the inorganic filler is selected from carbon black, silicon dioxide, calcium carbonate, and titanium dioxide. 10. An inorganic filler having an iodine adsorption amount of 35 to 200 mg /
The rubber composition according to claim 9, which is carbon black having a DBP oil absorption of 70 to 180 ml / 100 g. 11. The rubber composition according to claim 1, wherein the rubber composition does not substantially contain an amine-based antioxidant. 12. A rubber component comprising a diene rubber and an ethylene-propylene-diolefin copolymer rubber, wherein the rubber contains an inorganic filler in an amount of 20 to 200 parts by weight based on 100 parts by weight of the rubber component. -The propylene-diolefin copolymer has A. Glass transition temperature Tg (measured by DSC) ≤ -40 ° C B. Iodine value = 10 to 34 C. 220,000 ≤ weight average molecular weight ≤ 600,000 D. Ethylene content = 68 to 85 mol% E.2.0 ≦ Molecular weight distribution (M _w / M _n ) <3.0 F.95 ≦ 1.5 × (iodine value) + (ethylene content) ≦ 120 G.90 ≦ (Weight average molecular weight) × 10 ^-4 + (Ethylene content)
Satisfies all conditions of ≦ 160 and the content is 100
When producing a vulcanizable rubber composition in an amount of 20 to 80 parts by weight per 100 parts by weight of an ethylene-propylene-diolefin copolymer rubber, 10 to 100 parts by weight of the inorganic filler is used. A method for producing a rubber composition, characterized in that: 13. The method according to claim 12, wherein the diolefin component of the ethylene-propylene-diolefin copolymer rubber is ethylidene norbornene. 14. The method for producing a rubber composition according to claim 12, wherein the inorganic filler is carbon black. 15. The method for producing a rubber composition according to claim 12, wherein the ethylene-propylene-diolefin copolymer rubber is used as an oil-extended rubber. 16. The method for producing a rubber composition according to claim 12, wherein the rubber composition does not substantially contain an amine-based antioxidant.