JP3191589B2 - Ethylene-α-olefin-non-conjugated diene copolymer rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene-.alpha.-olefin-non-conjugated diene copolymer rubber composition which is excellent in workability, sealability, etc. and is suitable for a wide range of uses including sealing materials for automobiles, particularly suitable as sponge rubber. .

[0002]

2. Description of the Related Art Ethylene-.alpha.-olefin-non-conjugated diene copolymer rubber is excellent in heat resistance, ozone resistance, weather resistance and the like. Is widely used as a seal material for door seals, roof side rails, trunk seals, etc., but with the improvement of automobile performance, the performance of sponge rubber composed of ethylene-α-olefin-non-conjugated diene copolymer rubber is , High levels are required. For example,
When a car door is closed, the sealing material is left in a compressed state for a long time.
It is important that the compression set is generally expressed as an index. Therefore, it is necessary to increase the degree of crosslinking of the copolymer rubber. In addition, since the cross-sectional shape of the sealing material for automobiles has become complicated in recent years, when sponge rubber is manufactured by a normal continuous crosslinking method, a shape collapse occurs in which the sponge rubber is deformed by its own weight before completion of crosslinking and foaming,
Since the desired shape arises a problem that not be held, the mold excellent sponge rubber shape retention is an indication of collapse is required. In addition, strict conditions are imposed on the surface properties in order to increase the added value of sponge rubber, and further, in order to increase productivity, kneading workability, roll workability,
It is necessary to have excellent processability such as extrusion processability,
In particular, it is important that a “gel” due to shear strain and thermal history during processing is not easily generated. In order to solve these requirements, many attempts have been made to combine a low molecular weight component copolymer and a high molecular weight component copolymer in a rubber composition containing an ethylene-α-olefin-nonconjugated diene copolymer rubber. It has been done. However, in such a rubber composition, the number of factors that have a significant effect on the properties of the composition and the sponge rubber obtained therefrom is large, and these factors are complicatedly correlated. In fact, it is extremely difficult to select and combine. For example, JP-A-3-146531 discloses that a copolymer rubber A and a copolymer rubber B are used.
Ethylene / α-olefin weight ratio of 73/27 to 40 /
60, iodine number of 8 to 33, and Mooney viscosity (ML
_{1 + 4} 121 ° C.) is 130 to 195, and the copolymer rubber B
Has an ethylene / α-olefin weight ratio of 73/27 to 4
0/60, an amount having an iodine value of 10 to 36, and
A rubber composition having a d-viscosity (ML _{1 + 4} 121 ° C.) of 20 to 55 is disclosed, but the rubber composition has a low element number like a low molecular weight component copolymer, and thus has a sufficient shape. There is a problem that retention cannot be obtained. Also, Japanese Patent Laid-Open No. 4-8
No. 0245 discloses an ethylene / α-olefin weight ratio of 73/27 to 40/60, an iodine value of 10 to 36, and an iodine value ratio of a low molecular weight component copolymer and a high molecular weight component copolymer. 1.1 / 1 to 4/1, Mooney viscosity (ML _{1 + 4} 1
(21 ° C.) is 50 to 100, but the rubber composition has a problem that it tends to gel during processing because the content of the high molecular weight component copolymer is too high. That is, it is impossible for the conventional rubber composition to simultaneously suppress the formation of “gel” during processing and maintain shape retention without impairing other properties.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an ethylene-α which suppresses the formation of “gel” during processing, is excellent in shape retention, and is also excellent in extrusion processability, compression set, sponge surface skin and the like. -To provide an olefin-non-conjugated diene copolymer rubber composition.

[0004]

The present invention comprises a low molecular weight component copolymer and a low molecular weight component copolymer, wherein the low molecular weight component copolymer has a Mooney viscosity (ML _{1 +} 4,100 ℃)
Is 10 to 150, and the α-olefin content is ethylene and α -olefin.
An ethylene-α-olefin-nonconjugated diene copolymer having an iodine value of 30 to 60% by weight and an iodine value of 37 to 65 with respect to the total amount of olefin, and the high molecular weight component copolymer is Viscosity (ML _{1 + 4} , 100 ° C) 100-5
00, α-olefin content is ethylene and α-olefin
20-50 wt% and as iodine value of the total amount is 10 to 55 ethylene -α- olefin and - of a non-conjugated diene copolymer, low molecular weight component copolymer and the high molecular weight component copolymer And the prime value ratio is 1.1 / 1 to 4/1,
The weight ratio of the low molecular weight component copolymer to the high molecular weight component copolymer is 80/20 to 95/5, and the Mooney viscosity of the mixture of the low molecular weight component copolymer and the high molecular weight component copolymer (ML _{1+ 4,} ethylene 100 ° C.) is 30 to 250 -
α-olefin-non-conjugated diene copolymer rubber composition.

Hereinafter, the present invention will be described in detail. This will clarify the objects, configurations and effects of the present invention. Ethylene-α-olefin-non-conjugated diene copolymer The ethylene-α-olefin-non-conjugated diene copolymer rubber composition of the present invention (hereinafter, referred to as “copolymer rubber composition”).
Contains two types of ethylene-α-olefin-non-conjugated diene copolymers (hereinafter, referred to as “copolymer rubber”) that form a low molecular weight component copolymer and a high molecular weight component copolymer. In the copolymer rubber, examples of the α-olefin include α-olefins having 3 to 12 carbon atoms, and specifically, propylene, butene-1, 3-
Methylbutene-1, pentene-1, 3-methylpentene-1, 4-methylpentene-1, 3-ethylpentene
1, hexene-1, octene-1, decene-1, dodecene-1, and the like, with propylene being particularly preferred. These α-olefins can be used alone or in combination of two or more. The α-olefin content in the copolymer rubber is determined by comparing ethylene and α-olefin.
The low molecular weight component copolymer is 30 to 60% by weight, preferably 35 to 55% by weight, and the high molecular weight component copolymer is 20 to 50% by weight, preferably 20 to 45% by weight based on the total amount.
% By weight. Further, from the viewpoint of roll workability during processing, flowability during extrusion, and the like, it is preferable that the α-olefin content of the low molecular weight component copolymer is higher than the α-olefin content of the high molecular weight component copolymer. Examples of the non-conjugated diene include ethylidene norbornene, dicyclopentadiene, 5-vinyl-2-norbornene, 2,5-norbornadiene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 7-octadiene,
1,9-decadiene, 1,11-dodecadiene, 3,6
-Dimethyl-1,7-octadiene, 4,5-dimethyl-1,7-octadiene and the like can be mentioned, and ethylidene norbornene and dicyclopentadiene are particularly preferable. The non-conjugated dienes can be used alone or as a mixture of two or more. In the present invention, the copolymer rubber has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 10 to 150, preferably 30 to 100 for a low molecular weight component copolymer, and a high molecular weight component copolymer. Is from 100 to 500, preferably from 150 to 450. In this case, if the Mooney viscosity of the low molecular weight component copolymer is less than 10, the strength of the sponge rubber and the shape retention during cross-linking / foaming are reduced.
If it exceeds 50, the kneading processability is impaired. On the other hand, if the high molecular weight component copolymer has a Mooney viscosity of less than 100, the strength and shape retention of the sponge rubber decrease, while if it exceeds 500, the kneading processability is impaired. In the present invention,
The Mooney viscosity of the low molecular weight component copolymer and the Mooney viscosity of the high molecular weight component copolymer are determined by appropriately adjusting the Mooney viscosity of the other copolymer according to the Mooney viscosity of one of the copolymers. The difference in Mooney viscosity (ML _{1 + 4} , 100 ° C.) is usually 30 or more, preferably 50 to 450. The iodine value of the copolymer rubber is such that the low molecular weight component copolymer is 37 to 65, preferably 37 to 5
5, and the high molecular weight component copolymer is 10 to 55, preferably 10 to 35. In this case, if the iodine value of the low molecular weight component copolymer is less than 37, it is difficult to increase the degree of crosslinking of the composition, and the compression set of the sponge rubber also becomes large. It is difficult to achieve. Further, when the element number is less than 10 as in the case of the high molecular weight component copolymer, compression set and shape retention during crosslinking / foaming are impaired, and when it exceeds 55, it is difficult to achieve a high foaming degree. . The iodine value ratio between the low molecular weight component copolymer and the high molecular weight component copolymer is 1.1 / 1 to 1.
4/1, preferably 1.5 / 1 to 3.5 / 1. In this case, if the element value ratio is less than 1.1 / 1, the sponge surface is particularly poor and a "gel" tends to be generated during processing. On the other hand, if it exceeds 4/1, the shape at the time of crosslinking and foaming is increased. Retention is reduced. The weight ratio of the low molecular weight component copolymer to the high molecular weight component copolymer is from 80/20 to 95/5. In this case, if the weight ratio is less than 80/20, the shape retention during crosslinking / foaming is inferior, gelation is likely to occur, and the surface of the sponge surface becomes insufficient. The shape retention at the time decreases. The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the mixture of the low molecular weight component copolymer and the high molecular weight component copolymer is 30 to 250,
Preferably it is 50-200. In this case, if the Mooney viscosity is less than 30, the shape retention at the time of crosslinking and foaming is impaired, while if it exceeds 250, kneading processability and extrusion processability are reduced. In the present invention, the low molecular weight component copolymer and the high molecular weight component copolymer can be used alone or in combination of two or more.

[0006] The low molecular weight component copolymer and the high molecular weight component copolymer used in the present invention can be prepared by a usual polymerization method using a medium / low pressure method, for example, by preparing a transition metal compound and an organometallic compound in a suitable solvent. In the presence of a Ziegler-Natta catalyst, for example, a catalyst comprising at least one solvent-soluble vanadium compound and at least one organoaluminum compound, ethylene, α-olefin and a non-conjugated diene are optionally used as a molecular weight regulator. It can be produced by a method of polymerizing while supplying hydrogen, and the polymerization at that time can be carried out by a gas phase method (fluidized bed or stirred bed) or a liquid phase method (slurry method or solution method). As the solvent-soluble vanadium compound, VO
Preference is given to Cl ₃ , VCl ₄ , VOCl ₃ or the reaction product of at least one VCl ₄ with at least one alcohol. In this case, as the alcohol, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, t-butanol, n-hexanol, n-octanol, 2-ethylhexanol, n-decanol, n-decanol Dodecanol and the like can be mentioned, among which alcohols having 3 to 8 carbon atoms are preferable. Examples of the organoaluminum compound include triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum,
Diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum dichloride, butylaluminum dichloride,
Examples thereof include methylaluminoxane, which is a reaction product of trimethylaluminum and water, and these organoaluminum compounds can be used alone or in combination of two or more. Particularly preferred organoaluminum compounds are ethylaluminum sesquichloride, butylaluminum sesquichloride, a mixture of ethylaluminum sesquichloride and triisobutylaluminum, and a mixture of triisobutylaluminum and butylaluminum sesquichloride. As the solvent, a hydrocarbon solvent is usually used, and preferred hydrocarbon solvents include n-pentane, n-hexane, n-heptane, n-octane, isooctane, cyclohexane and the like. These hydrocarbon solvents can be used alone or in combination of two or more. The copolymer rubber composition of the present invention comprises (a) separately producing a low molecular weight component copolymer and a high molecular weight component copolymer, then mixing the two, removing the solvent, and forming a solid composition. How to get, or (b)
Using two polymerization tanks connected in series, one of the low molecular weight component copolymer and the high molecular weight component copolymer is produced in the first polymerization tank, and the polymerization product is produced in the second polymerization tank. It can be prepared by a method in which a solid composition is obtained by supplying the mixture to a polymerization tank, producing the other copolymer in the second polymerization tank, and then removing the solvent.

Ingredients Next, a filler, a softening agent, a crosslinking agent, a foaming agent, and the like can be incorporated into the copolymer rubber composition of the present invention, if necessary. As the filler, for example, SRF, FEF, HA
Carbon blacks such as F, ISAF, SAF, FT, and MT; and inorganic fillers such as fine silica particles, calcium carbonate, magnesium carbonate, clay, and talc. These fillers can be used alone or in combination of two or more. The compounding amount of the filler in the present invention is usually 50 to 200 parts by weight per 100 parts by weight of the total of the low molecular weight component copolymer and the high molecular weight component copolymer. Examples of the softener include process oils, such as aromatic oils, naphthenic oils, and paraffin oils, which are usually used for rubber; and vegetable oils, such as coconut oil. Of these softeners, process oils are preferred, and paraffin oil is particularly preferred. These softeners can be used alone or in combination of two or more. The amount of the softener in the present invention is usually 30 to 150 parts by weight per 100 parts by weight of the total of the low molecular weight component copolymer and the high molecular weight component copolymer. Examples of the crosslinking agent include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur; inorganic vulcanizing agents such as sulfur chloride, selenium, and tellurium; morpholine disulfides, alkylphenol disulfides, thiuram disulfides, Sulfur-containing organic compounds such as dithiocarbamic acids;
1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-bis (t-butylperoxy-
Organic peroxides such as isopropyl) benzene and the like can be mentioned. These crosslinking agents can be used alone or in combination of two or more. The amount of the crosslinking agent in the present invention varies depending on the type of the crosslinking agent, the iodine value of the copolymer rubber composition, etc., for example, in the case of sulfur, the total of the low molecular weight component copolymer and the high molecular weight component copolymer. It is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight. When sulfur is used as a cross-linking agent, a vulcanization accelerator and a vulcanization accelerator may be further added as necessary. As such a vulcanization accelerator,
For example, aldehyde ammonias such as hexamethylenetetramine and acetaldehyde ammonia; guanidines such as diphenylguanidine, di (o-tolyl) guanidine, o-tolyl-biguanide; thiocarbanilide, di (o
-Tolyl) thiourea, N, N′-diethylthiourea, tetramethylthiourea, trimethylthiourea,
Thioureas such as dilaurylthiourea; mercaptobenzothiazole, dibenzothiazole disulfide, 2
-(4-morpholinothio) benzothiazole, 2-
Benzothiazoles such as (2,4-dinitrophenyl) mercaptobenzothiazole, N, N '-(diethylthiocarbamoylthio) benzothiazole; Nt-butyl-2-benzothiazylsulfenamide, N, N' −
Sulfenamides such as dicyclohexyl-2-benzothiazylsulfenamide, N, N'-diisopropyl-2-benzothiazylsulfenamide, N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide Thiurams such as tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide; zinc dimethylthiocarbamate, zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, ethyl Thiocarbamic acids such as zinc phenyldithiocarbamate, sodium dimethyldithiocarbamate, copper dimethyldithiocarbamate, tellurium dimethylthiocarbamate and iron dimethylthiocarbamate Salts: Xanthates such as zinc butylthioxanthogenate and zinc isopropylxanthogenate can be mentioned. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerator in the present invention is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight per 100 parts by weight of the total of the low molecular weight component copolymer and the high molecular weight component copolymer. Parts by weight. Further, as the vulcanization accelerating aid, for example, magnesium oxide, zinc white, litharge,
Metal oxides such as red lead and white lead; organic acids such as stearic acid, oleic acid, and zinc stearate; and the like; zinc white and stearic acid are particularly preferable. These vulcanization accelerators can be used alone or in combination of two or more. The amount of the vulcanization accelerator in the present invention is usually 3 to 20 parts by weight per 100 parts by weight of the total of the low molecular weight component copolymer and the high molecular weight component copolymer. When using an organic peroxide as a crosslinking agent,
If necessary, a crosslinking aid can be further added.
Examples of such a crosslinking aid include sulfur and sulfur or a sulfur compound such as dipentamethylenethiuram tetrasulfide; polyethylene dimethacrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate,
Polyfunctional monomers such as metaphenylene bismaleimide and toluylene bismaleimide; p-quinone oxime,
Oxime compounds such as p, p'-benzoylquinone oxime and the like can be mentioned. These crosslinking assistants can be used alone or in combination of two or more. Examples of the blowing agent include inorganic blowing agents such as ammonium carbonate, sodium bicarbonate, and anhydrous sodium nitrate;
Dinitrosopentamethylenetetramine, N, N'-dimethyl-N, N'-dinitrosoterephthalamide, benzenesulfonylhydrazide, p, p'-oxybis (benzenesulfonylhydrazide), 3,3'-disulfonehydrazidediphenylsulfone, azo Organic blowing agents such as isobutyronitrile and azobisformamide can be mentioned. These foaming agents can be used alone or in combination of two or more. Further, a foaming aid such as a urea-based, organic acid-based, or metal salt-based foaming agent can be used together with the foaming agent. The amount of the foaming agent and the foaming aid in the present invention varies depending on the kind and the desired degree of foaming, but the foaming agent per 100 parts by weight of the low molecular weight component copolymer and the high molecular weight component copolymer in total is , Usually 0.5-2
0 parts by weight, preferably 1 to 15 parts by weight, and the foaming aid is usually 1 to 20 parts by weight. Further, the copolymer rubber composition of the present invention may optionally contain a moisture absorbent, a plasticizer, an antioxidant, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a release agent, a flame retardant, and an antistatic agent. , Dyes and pigments, other additives such as fungicides, and other polymers such as natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butyl rubber, Acrylic rubber,
Ethylene-α-olefin rubber, low density polyethylene,
Medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene and the like can also be blended. In preparing the copolymer rubber composition, a usual kneader such as a Banbury mixer, a roll mixer, and an extruder can be used.

Production of Sponge Rubber The copolymer rubber composition of the present invention is particularly useful for sponge rubber. When producing such a sponge rubber, the crosslinking agent, a foaming agent and the like are blended with the copolymer rubber composition to form a rubber compound, and then, for example, crosslinking and foaming are performed by a generally used method. Do. There are no particular restrictions on the method and order of compounding each component when producing the sponge rubber, and a kneading machine may be used, but in particular, low-molecular-weight components may be mixed using a Banbury mixer. After kneading a polymer, a high molecular weight component copolymer, a filler, a softening agent, and the like, it is preferable to knead a crosslinking agent, a foaming agent, a foaming aid, and the like using a roll mixer. In the case of kneading using an extruder, the low molecular weight component copolymer and the high molecular weight component copolymer and a part of the compounding components are preliminarily kneaded by a Banbury mixer or the like, and then supplied to the extruder. The components can be separately supplied to an extruder and kneaded, or the low molecular weight component copolymer, the high molecular weight component copolymer and all the components can be directly supplied to the extruder and kneaded. Then, according to the procedure used in the production of ordinary sponge rubber, for example, a rubber compound
The desired sponge rubber is manufactured by a method of crosslinking and foaming by heating in a mold of a foaming device, or a method of forming a rubber compound into a desired shape using an extruder and then heating the compound in a crosslinking tank. be able to. The heating temperature and heating time at the time of crosslinking and foaming vary depending on the type of the crosslinking agent and the foaming agent, the degree of foaming, and the like.
The temperature is 0 ° C, preferably 180 to 250 ° C, and the heating time is usually 2 to 15 minutes, preferably 3 to 10 minutes.

[0009]

The present invention will be described below more specifically with reference to examples and comparative examples. However, the present invention is not limited to these embodiments. Each measurement and evaluation in Examples and Comparative Examples was performed according to the following procedures. (1) Propylene content (% by weight) It was measured by an infrared absorption spectrum method. (2) Iodine value Measured by an infrared absorption spectrum method. (3) Mooney viscosity (ML _{1 + 4} 100 ° C.) Measurement was performed at a measurement temperature of 100 ° C., a residual heat time of 1 minute, and a time of 4 minutes until the viscosity was read. (4) Extrusion processability (Garve die rating) For the compound [II] of each Example and Comparative Example,
Attach a garbage die to a 50 mm extruder and set the cylinder temperature to 6
Extrusion was performed at 0 ° C., a die temperature of 80 ° C., and a screw rotation speed of 30 rpm, and the extrudability was evaluated based on ASTM-D2230. (5) Shape Retention (%) A molded product obtained by extruding the compound [II] of each Example and Comparative Example using a die having the shape shown in FIG. 1 was left horizontally in an atmosphere of 220 ° C. for 7 minutes. After that, it is cross-linked / foamed and left at room temperature.
The ratio was evaluated by the ratio (La / Lb) × 100 with b. (6) Gelation time About the compound [I] of each Example and Comparative Example, a stress relaxation measuring device (JSR Estragraph, manufactured by Nippon Synthetic Rubber Co., Ltd., Japanese Patent Publication No. 5-25059) was used.
The gelation time was defined as the temperature at which the torque started to increase measured at 130 ° C. and a shear strain rate of 20 per second. The longer the gelation time, the harder it is to form a "gel". (7) Sponge physical properties Specific gravity Measured in accordance with the Japan Rubber Association Standard Standards / Physical test method for expanded rubber. Compression set In accordance with JIS K6301, a molded product extruded using a die having the shape shown in FIG. 1 is subjected to a compression strain of 50% in the longitudinal direction of FIG. 1, and the compression strain after 70 hours at 70 ° C. It was measured. Surface skin Based on the smoothness of the sponge rubber surface, gloss, the presence or absence of adhesion, etc., it was visually evaluated on a scale of excellent: ○, normal: △, poor: ×.

Examples 1 to 5 and Comparative Examples 1 to 2 Using the low molecular weight component copolymer and the high molecular weight component copolymer shown in Table 1, the component [I] shown in Table 2 was blended.
A compound [I] was obtained by kneading at 130 ° C. for 200 seconds at a rotation speed of 80 rpm using a mold Banbury mixer (contents: 1.7 liters). To the compound [I], the component [II] shown in Table 2 was blended, and 50
Using a 10-inch roll mixer maintained at 0 ° C., the front roll rotation speed (rpm) / the rear roll rotation speed (rpm) = 2
4/22, kneading for 5 minutes, compound [II]
I got Thereafter, a die having the shape shown in FIG. 1 was attached to a 50 mm extruder, the cylinder temperature was set to 60 ° C., the die temperature was set to 80 ° C., and the screw rotation speed was set to 30 rpm, and the compound [II] was extruded to obtain a molded product. After that, 250 ° C
Was heated in a hot air tank for 5 minutes to perform crosslinking and foaming, thereby obtaining a sponge rubber. These compound [I], compound [II] and sponge rubber were evaluated in the above-described evaluation procedure. Table 2 shows the evaluation results. As a result, the copolymer rubber composition of the present invention is less likely to form a “gel” during processing, has excellent shape retention properties, and has excellent extrudability, compression set, sponge surface texture, etc., and excellent properties. Have a balance. On the other hand, in Comparative Example 1, the weight ratio between the low molecular weight component copolymer and the high molecular weight component copolymer was 80/2.
Since it is less than 0, the shape retention property is particularly poor, the gel is easily formed, and the surface of the sponge surface is insufficient. Also,
In Comparative Example 2, since the low-molecular-weight component copolymer and the high-molecular-weight component copolymer had an element number ratio of less than 1.1 / 1, the sponge surface was particularly inferior and gelled easily, and the foaming degree was low. Is also inadequate.

[0011]

[Table 1]

[0012]

[Table 2]

In Table 2, (* 1) to (* 11) are as follows. (* 1) Asahi Carbon Co., Ltd. Asahi 50HG (* 2) Asahi Carbon Co., Ltd. Asahi F200 (* 3) Idemitsu Kosan Co., Ltd. Diana Process Oil PW
-380 (* 4) Vesta PP (* 5) Mercaptobenzothiazole (* 6) Zinc dimethyldithiocarbamate (* 7) Zinc di-n-butyldithiocarbamate (* 8) Dipentamethylenethiuramtetra Sulfide (* 9) Tetraethylthiuram disulfide (* 10) 4,4'-dithio-bis-dimorpholine (* 11) p, p'-oxybis (benzenesulfonylhydrazide)

[0014]

Industrial Applicability The copolymer rubber composition of the present invention hardly generates a "gel" during processing, is excellent in shape retention, and is also excellent in extrusion processability, compression set, sponge surface texture and the like. . Therefore, the copolymer rubber composition of the present invention can be very suitably used as a sealing material for automobile door seals, roof side rails, trunk seals and the like, especially as a sponge rubber, and also for other transport machinery. It is useful for a wide range of applications including sealing materials for civil engineering and construction, sealing materials for general machinery and equipment, and wire coating.

[Brief description of the drawings]

FIG. 1 is a view showing the shape of a die used for evaluation of shape retention and compression set.

──────────────────────────────────────────────────の Continued on the front page (72) Fumio Tsutsumi, Inventor 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (72) Inventor Yoji Mori 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan (56) References JP-A-4-309544 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 23/02 C08L 23/16-23/18 C08F 210/18

Claims (1)

(57) [Claims] 1. A low molecular weight component copolymer comprising a low molecular weight component copolymer and a high molecular weight component copolymer, wherein the low molecular weight component copolymer has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of 10 to 150, α The olefin content is relative to the total amount of ethylene and α-olefin;
30 to 60 wt% and as iodine value and is 37 to 65 ethylene -α- olefin - of a non-conjugated diene copolymer, high molecular weight component copolymer, arm - two - viscosity (ML
_{1 + 4} , 100 ° C.) is 100-500, and the α-olefin content is 20-500 with respect to the total amount of ethylene and α-olefin.
An ethylene-α-olefin-nonconjugated diene copolymer having an iodine value of 10 to 55% by weight and a low molecular weight component copolymer and a high molecular weight component copolymer having an iodine value ratio of 1. 1/1 to 4/1, the weight ratio of the low molecular weight component copolymer to the high molecular weight component copolymer is 80/20 to 95 /
5, and the Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the mixture of the low molecular weight component copolymer and the high molecular weight component copolymer is 3
An ethylene-α-olefin-non-conjugated diene copolymer rubber composition having 0 to 250.