JPH08325424A - Rubber composition - Google Patents

Abstract

PURPOSE: To obtain a rubber composition which can fully exhibit the characteristic features of an ethylene/propylene/nonconjugated diene copolymer rubber excellent in heat resistance, weather resistance, ozone resistance, chemical resistance, etc., and can give a high-hardness vulcanized rubber composition having excellent processability and a sufficiently high hardness. CONSTITUTION: This rubber composition contains a rubber component comprising an ethylene/ propylene/ nonconjugated diene copolymer rubber (A) having a Mooney viscosity (ML1+4 , 100 deg.C) of 40 or below and an ethylene/(ethylene + propylene) weight ratio of (75-95)/100 and a liquid polyisoprene rubber (B) having a degree of hydrogenation of double bonds of 70% or above and having an A/B weight ratio of 65/35-95/5.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber composition, a high-hardness vulcanized rubber composition, a weather strip for automobiles, a glass run channel for automobiles, or a gasket for construction. More specifically, the present invention makes full use of the characteristics of the ethylene-propylene-non-conjugated diene copolymer rubber which is excellent in heat resistance, weather resistance, ozone resistance, chemical resistance, and the like, and is excellent in processability, and is sufficient. A rubber composition capable of providing a high hardness vulcanized rubber composition having high hardness, a high hardness vulcanized rubber composition obtained by sulfur vulcanizing the rubber composition, an automobile weather strip using the same, and an automobile It relates to glass run channels or building gaskets.

[0002]

2. Description of the Related Art Ethylene-propylene-non-conjugated diene copolymer rubbers are widely used in various automobile parts because of their excellent heat resistance, weather resistance, ozone resistance and chemical resistance. By the way, it is one of the essential requirements for a rubber to be put to practical use that it has excellent processability such as roll processability and extrusion processability. On the other hand, among automobile parts, a high hardness rubber may be used alone or a sponge rubber and a high hardness rubber may be integrally used for a weather strip or a glass run channel. Further, as for the glazing gasket, the airtight gasket, and the joint gasket in the building gasket, the high hardness rubber may be used alone or in combination with other rubber. The high-hardness rubber used for such applications is required to have sufficiently high hardness and excellent workability.

Usually, in order to increase the hardness of the vulcanized rubber, it is necessary to increase the amount of carbon black compounded. However, increasing the amount of carbon black increases the Mooney viscosity of the unvulcanized compound and significantly deteriorates the processability. Will end up. As described above, it is generally difficult to simultaneously increase the hardness of the vulcanized rubber and improve the processability (reduce the Mooney viscosity).

As a method for improving the processability, a method of compounding liquid polyisoprene rubber with EPDM is shown in Japanese Patent Application Publication No. 3-73584, and the hardness of the vulcanized rubber (JIS- A) is 80 or less,
We have a sufficiently high hardness (JIS-A) 90
No more. In the case of this embodiment as well, the hardness is increased by increasing the blending amount of carbon black, but in that case, the Mooney viscosity is also increased, and the original workability is deteriorated.

From this point of view, ethylene-
It can be said that a rubber composition capable of providing a high-hardness vulcanized rubber composition having a sufficiently high hardness and making good use of the characteristics of the propylene-non-conjugated diene copolymer rubber has not yet been realized. .

[0006]

In view of such circumstances, the problem to be solved by the present invention is ethylene-propylene-excellent in heat resistance, weather resistance, ozone resistance, chemical resistance and the like.
A rubber composition capable of sufficiently providing the properties of a non-conjugated diene copolymer rubber, having excellent processability, and capable of providing a high hardness vulcanized rubber composition having sufficiently high hardness, and sulfur vulcanizing the rubber composition. A high-hardness vulcanized rubber composition thus obtained and a weather strip for automobiles, a glass run channel for automobiles, or a gasket for construction using the same are provided.

[0007]

[Means for Solving the Problems] Therefore,
Excellent workability without sacrificing the excellent properties of
Moreover, in order to obtain a high-hardness vulcanized rubber composition having a sufficiently high hardness, it was found that the above object can be achieved by blending a specific liquid polyisoprene rubber with a specific EPDM, and the present invention is achieved. It came to completion.

That is, the first invention of the present invention contains the following components (A) and (B) as rubber components, and the weight ratio of (A) / (B) is 65/35 to 95 /. No. 5 rubber composition. (A) component: Mooney viscosity (ML _{1 + 4} 100 ° C.) is 40
Below and ethylene / (ethylene + propylene)
Ethylene-propylene-non-conjugated diene copolymer rubber having a weight ratio of (75 to 95) / 100 (B) component: liquid polyisoprene rubber in which 70% or more of double bonds are hydrogenated

The second invention of the present invention is obtained by sulfur vulcanizing the rubber composition of the first invention, and has a hardness (J
It relates to a high hardness vulcanized rubber composition having an IS-A) of 90 or more.

Furthermore, the third invention of the present invention relates to a weather strip for automobiles, a glass run channel for automobiles, or a gasket for construction, which partly uses the rubber composition of the first invention.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) of the present invention has a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 40 or less and an ethylene / (ethylene + propylene) weight ratio of (75-9).
5) / 100 ethylene-propylene-non-conjugated diene copolymer rubber.

As the non-conjugated diene as the component (A), 1,
Examples include 4-pentadiene, 1,4-hexadiene, divinylbenzene, dicyclopentadiene, methylene norbornene, ethylidene norbornene (ENB), vinyl norbornene and the like. These may be used alone or in combination of two or more.

The content of the non-conjugated diene in the component (A) is an iodine value and is usually 2-35, preferably 10-2.
It is 5. If the content of the non-conjugated diene is too small, the physical properties at the time of sulfur vulcanization may decrease, while if the content is too large, the heat resistance and ozone resistance after sulfur vulcanization may deteriorate. .

The Mooney viscosity of component (A) (ML _{1 + 4} 10
0 ° C.) is 40 or less, preferably 35-5. If the Mooney viscosity is too high, the Mooney viscosity (ML _{1 + 4} 100 ° C.) of the unvulcanized compound also becomes high, resulting in poor processability.

The weight ratio of ethylene / (ethylene + propylene) of the component (A) is (75 to 95) / 100, preferably (78 to 90) / 100. When the proportion of ethylene increases, the crystallinity of ethylene increases and the hardness of the vulcanized rubber increases. Therefore, if the ethylene ratio is too small, sufficiently high hardness cannot be obtained. However, if the ethylene ratio is too high, production of EPDM may be difficult, or the processability of the unvulcanized compound may be adversely affected.

Component (B) of the present invention comprises 70% of double bonds.
Above, preferably at least 75% is hydrogenated liquid polyisoprene rubber. If the hydrogenation rate is too small, a sufficiently high hardness cannot be obtained.

The component (B) is liquid polyisoprene, and its viscosity average molecular weight is usually 5,000 to 50,000.
Is in the range. Workability is poor when solid polyisoprene is used without the use of the present invention.

The weight ratio of (A) / (B) in the rubber composition of the present invention is 65/35 to 95/5, preferably 70/30.
~ 95/5. If the amount of the component (A) is too small, a sufficiently high hardness cannot be obtained, while if the amount of the component (A) is too large, the workability is poor.

When using the rubber composition of the present invention, a reinforcing agent such as carbon black or silica and a plasticizer such as mineral oil are used in combination. For example, 50 to 200 parts by weight of FEF carbon black and 100 parts by weight or less of paraffin-based process oil are used per 100 parts by weight of the rubber component. If the amount of the reinforcing agent is too small, a sufficiently high hardness may not be obtained, while if the amount of the reinforcing agent is too large, rubber properties such as elasticity may deteriorate. If the amount of the plasticizer is too small, the processability may be poor. On the other hand, if the amount of the plasticizer is too large, a sufficiently high hardness may not be obtained.

The rubber composition of the present invention comprises the above components and vulcanizing agent, and if necessary, an antioxidant, a processing aid,
Stearic acid, zinc oxide, filler, vulcanization accelerator, etc.
A high hardness vulcanized rubber composition can be obtained by kneading using a Banbury mixer, an open roll or the like to form a compound, and molding and vulcanizing the compound. As the vulcanizing agent, sulfur, organic peroxide and the like can be used, but it is preferable to use sulfur from the viewpoint that vulcanization in air is possible. The amount of sulfur used is 0.5 to 4 parts by weight per 100 parts by weight of the rubber component. If the amount used is too small, a sufficiently high hardness may not be obtained. On the other hand, if the amount used is too large, blooming occurs on the surface of the product and the external appearance deteriorates, heat resistance and compression set. May get worse. The high-hardness vulcanized rubber composition thus obtained can realize a high hardness of JIS-A hardness of 90 or more.

The rubber composition of the present invention can be used in a wide range of fields by taking advantage of its excellent properties. Suitable applications thereof include weather strips for automobiles, glass run channels for automobiles, and gaskets for construction. it can. That is, a weather strip for automobiles,
In the rubber portion of the glass run channel for automobiles or the gasket for construction, a high hardness rubber is usually used alone or in combination with a sponge or another rubber, and the rubber composition of the present invention is suitable for the high hardness rubber portion. used.

[0022]

EXAMPLES Next, the present invention will be described with reference to examples. Examples 1 to 5 and Comparative Examples 1 to 6 100 parts by weight of FEF carbon black (“Asahi 60G” (trade name) manufactured by Asahi Carbon Co., Ltd.), process oil (Idemitsu Kosan Co., Ltd.) 5 parts by weight of "PW-90" (trade name) manufactured by Japan, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 2 parts by weight of polyethylene glycol (PEG4000), calcium oxide ("Vesta BS" manufactured by Inoue Lime Co., Ltd. (trade name) )) 3 parts by weight, Sox
2.5 parts by weight of CZ (vulcanization accelerator manufactured by Sumitomo Chemical Co., Ltd.),
Sox BZ (Sumitomo Chemical Co., Ltd. vulcanization accelerator) 1.0
Parts by weight, 0.5 parts by weight of Sox TT (vulcanization accelerator manufactured by Sumitomo Chemical Co., Ltd.) and 1.5 parts by weight of sulfur in a volume of 1.7
A compound was prepared by kneading with a liter BR type Banbury mixer and an open roll. At this time, the condition during kneading was visually observed, and the Mooney viscosity (ML _{1 + 4} 100 ° C.) of the obtained compound was measured to evaluate the processability. Next, vulcanize the obtained compound,
It was a vulcanized rubber composition. Vulcanized rubber composition JIS
Conforms to K6301, tensile strength (T _B), elongation (E _B) and hardness; were evaluated (H _S JIS-A). The results are shown in Table 1.

The results show the following. All examples according to the present invention show satisfactory results in all evaluation items. On the other hand, Comparative Example 1 lacking the component (B) of the present invention has a high Mooney viscosity of the compound and is inferior in processability. Comparative Example 2 in which the ethylene content of the component (A) is too low
Is inferior in hardness. The ethylene content of component (A) is too low,
In addition, the Mooney viscosity of the component (A) is too high, and Comparative Example 3 has a high Mooney viscosity and is inferior in workability and inferior in hardness. The Mooney viscosity of the component (A) is too high, and Comparative Example 4 has a high Mooney viscosity and is inferior in processability. Comparative Example 5 using a non-hydrogenated polyisoprene rubber as the component (B) is inferior in hardness. 70% hydrogen content as component (B)
Comparative Example 6 using a polyisoprene rubber of less than 1 is inferior in hardness.

[0024]

[Table 1] ---------------------------------- Example 1 2 3 4 5 Formulation (A) component * 1 ML _{1+ 4} (100 ℃) 35 ← ← ← ← E / E + P wt ratio * 2 80/100 ← ← ← ← (B) component * 3 Hydrogenation rate% * 4 90 ← ← 75 95 Mv * 5 25000 ← ← 29000 ← A / B wt ratio * 6 90/10 80/20 70/30 90/10 ← Evaluation result compound ML _{1 + 4} (100 ℃) 73 62 51 70 72 Roll processability * 7 ○ ○ ○ ○ ○ Extrusion processability * 8 ○ ○ ○ ○ ○ Vulcanized physical properties T _B kgf / cm ² 153 129 115 135 149 E _B % 170 170 170 200 180 H _S (JIS-A) 91 91 90 90 91 −−−−−−−−−− −−−−−−−−−−−−−−−−−−−

[0025]

[Table 2] -------------------------------------------- Comparative Example 1 2 3 4 5 6 Formulation (A) component * 1 ML _{1 + 4} (100 ℃) 35 35 50 90 35 35 E / E + P wt ratio * 2 80/100 70/100 50/100 80/100 80/100 80/100 (B) component * 3 Water Additivity% * 4-90 ← ← 0 44 Mv * 5-25000 ← ← 47000 25000 A / B wt ratio * 6 100/0 90/10 ← ← ← 90/10 Evaluation result compound ML _{1 + 4} (100 ° C) 95 75 120 147 64 68 Roll processability * 7 × ○ × × ○ ○ Extrusion processability * 8 × ○ × × ○ ○ Vulcanization property T _B kgf / cm ² 160 157 147 234 108 130 E _B % 170 230 290 220 300 240 H _S (JIS-A) 91 86 84 91 86 87 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

* 1 Component (A): ethylene-propylene-ethylidene norbornene copolymer rubber * 2 E / E + P: ethylene / (ethylene + propylene) weight ratio of component (A) * 3 (B) component: listed in the table Liquid polyisoprene rubber having hydrogenation rate of * 4 Hydrogenation rate: Hydrogenation rate of double bond of component (B) * 5 Mv: viscosity average molecular weight * 6 A / B wt ratio: (A) component / (B ) Weight ratio of components * 7 Roll processability: The state of winding the compound around the roll at the time of kneading is indicated by ○ (good winding on the roll and good turning back) or × (bad winding on the roll and good turning back) Bad) evaluated. * 8 Extrudability: The extrudability of the unvulcanized compound was evaluated as O (high extrusion rate and smooth extruded product surface) or X (low extrusion rate and extruded product surface is not messy).

[0027]

As described above, according to the present invention, the characteristics of the ethylene-propylene-non-conjugated diene copolymer rubber excellent in heat resistance, weather resistance, ozone resistance, chemical resistance, etc. can be fully utilized and the processability is improved. And a rubber composition capable of providing a high hardness vulcanized rubber composition having a sufficiently high hardness, a high hardness vulcanized rubber composition obtained by sulfur vulcanizing the rubber composition, and an automobile using the same Weather strips, automotive glass run channels or architectural gaskets could be provided.

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Claims (4)

[Claims] 1. A rubber component containing the following components (A) and (B), and the weight ratio of (A) / (B) is 65 /
A rubber composition of 35 to 95/5. (A) component: Mooney viscosity (ML _{1 + 4} 100 ° C.) is 40
Below and ethylene / (ethylene + propylene)
Ethylene-propylene-non-conjugated diene copolymer rubber having a weight ratio of (75 to 95) / 100 (B) component: liquid polyisoprene rubber in which 70% or more of double bonds are hydrogenated 2. The component (B) has a viscosity average molecular weight of 5,000.
The rubber composition according to claim 1, which is -50000. 3. A high hardness vulcanized rubber composition obtained by sulfur vulcanizing the rubber composition according to claim 1 and having a hardness (JIS-A) of 90 or more. 4. A weather strip for automobiles, a glass run channel for automobiles, or a gasket for construction, which uses a part of the rubber composition according to claim 1.