JP2000072935A - Rubber composition for weather strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which can give a weather strip excellent in compression set resistance, mechanical strengths, and a balance among low- temperature properties by using a specified ethylene copolymer rubber and a vulcanizing agent and/or a crosslinking agent as the principal components. SOLUTION: The ethylene copolymer rubber used is one comprising ethylene units, 1-butene units, and nonconjugated polyene units and satisfying the following four requirements: the molar ratio of the ethylene units to the 1-butene units is 20:80 to 85:15; the iodine value is 15-45; the Mooney viscosity (ML1+4, 100 deg.C) is 25-350; and the glass transition temperature (Tg) as determined with a differential scanning calorimeter(DSC) is -50 to -80 deg.C. The nonconjugated polyene used is desirably a linear nonconjugated polyene represented by the formula: CH2=CH-X-CR1=CR2-R3 (wherein X is a 1-20C saturated or unsaturated hydrocarbon group; R1 and R2, which may be the same or different from each other, are each hydrogen or a 1-8C alkyl, provided that not both of them can be hydrogen simultaneously; and R3 is a 1-8C alkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition for a weatherstrip, and more particularly to a rubber composition for a weatherstrip which provides a vulcanized rubber having an excellent balance of compression set, mechanical strength and low-temperature properties. About.

[0002]

2. Description of the Related Art Conventionally, ethylene / α-olefin / non-conjugated diene copolymers are excellent in weather resistance, heat resistance, cold resistance, ozone resistance, etc., and are used as building materials, automobile parts, electric wire covering materials and the like. Widely used. In particular, many rubbers mainly composed of EPDM are used around doors and trunk rooms in order to provide soundproofness and waterproofness inside and outside the automobile. However, conventional EPDM is
When the vulcanization rate is low and a large amount of a vulcanization accelerator is added to the EPDM compound to increase the vulcanization rate, a problem of so-called blooming occurs in which the vulcanization accelerator emerges on the surface of the product. Further, the conventional EPDM is not satisfactory in physical properties such as settling resistance.

In recent years, the present applicant has disclosed Japanese Patent Application Laid-Open No. 2-51212.
In the publication, by using a linear non-conjugated diene represented by 7-methyl-1,6-octadiene,
A method for improving the co-vulcanization property of ethylene / α-olefin / non-conjugated diene-based copolymer rubber and conjugated diene-based rubber, which has a higher vulcanization rate than that of 5-ethylidene-2-norbornene, was proposed. Further, JP-A-7-33896 discloses that an ethylene / propylene / 7-methyl-1,6-octadiene copolymer rubber using a metallocene catalyst is excellent as a rubber for sponge.
However, ethylene / propylene / 7-methyl-
Although the 1,6-octadiene copolymer rubber composition is improved in vulcanization rate as compared with the conventional EPDM, the compression set and low-temperature properties are not at a level that can be sufficiently satisfied.

On the other hand, the present applicant has filed a Japanese Patent Application No. 8-35386.
In the specification of Japanese Patent No. 5 and Japanese Patent Application No. 10-36609, ethylene / α-olefin / non-conjugated diene copolymer having 6 to 12 carbon atoms is more excellent in balance between flexibility and compression set than EPDM. Proposed that. However, these copolymers are not at a satisfactory level in terms of mechanical strength as compared with EPDM.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition capable of obtaining a weather strip excellent in balance of compression set, mechanical strength and low-temperature properties by using a specific ethylene copolymer rubber. To provide things.

[0006]

According to the present invention, the following rubber composition for a weatherstrip is provided to achieve the above object of the present invention. (1) (A) an ethylene copolymer rubber having a unit derived from ethylene, a unit derived from 1-butene, and a unit derived from a non-conjugated polyene and satisfying the following requirements, and (B) vulcanization A rubber composition for a weather strip, comprising an agent and / or a crosslinking agent as a main component. Requirements The molar ratio (ethylene / 1-butene) of the unit derived from ethylene to the unit derived from 1-butene is 20/80.
８５85/15 Iodine value is 15〜45 Mooney viscosity (ML1 + 4, 100 ° C.) 25〜350
The glass transition temperature (Tg) determined by a differential scanning calorimeter (DSC) is −50 ° C. to −80 ° C. (2) The non-conjugated polyene in the ethylene copolymer rubber (A) is represented by the following formula: The rubber composition for a weatherstrip according to the above (1), which is a chain non-conjugated polyene represented by (I). Formula (I) CH ₂ ＣＨCH—X—CR ¹ ＣＲCR ² —R ³ (wherein, X represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and R ¹ and R ² are the same or different. Differently, it represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 8 carbon atoms, except that both R ¹ and R ² are hydrogen atoms. (2) The rubber composition for a weatherstrip according to the above (2), wherein the (A) ethylene copolymer rubber further contains a unit derived from α, ω-diene represented by the following formula (II): . Formula _{(II) CH 2 = CH- (} CH 2) m-CH = CH 2 ( wherein, m is an integer of from 1 to 10.)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The (A) ethylene copolymer rubber used in the rubber composition of the present invention comprises units derived from ethylene, 1-butene and a non-conjugated polyene (hereinafter referred to as “ethylene units”, “ethylene units”, respectively). 1-butene units "and" non-conjugated polyene units "). (A) Ethylene unit and 1 in ethylene copolymer rubber
-Molar ratio to butene units (ethylene / 1-butene) is
20 / 80-85 / 15, preferably 30 / 70-82
/ 18, more preferably 50/50 to 80/20 (the above requirement). When the molar ratio is within the above range,
The mechanical strength and the compression set are preferably maintained in a well-balanced manner.

The non-conjugated polyene includes, for example, 5
-Ethylidene-2-norbornene, dicyclopentadiene, 5-propylidene-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene, 1,
Cyclic polyenes such as 4-cyclohexadiene, 1,4-cyclooctadiene, and 1,5-cyclooctadiene;
1,4-hexadiene, 1,5-heptadiene, 1,6-
Examples include chain dienes such as octadiene, 1,7-nonadiene, and 1,8-decadiene.

Further, as the non-conjugated polyene, a chain non-conjugated polyene represented by the following formula (I) can be preferably mentioned. Specifically, 4-methyl-1,4-hexadiene, 5-methyl- 1,4-hexadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 3,7- Dimethyl-1,6-
Octadiene, 5,7-dimethyl-1,6-octadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,
7-nonadiene, 8-methyl-1,8-decadiene, 9
-Methyl-1,8-decadiene, 9-methyl-1,9-undecadiene, 10-methyl-1,9-undecadiene, 10-methyl-1,10-dodecadiene, 11-methyl-1,10-dodecadiene, 12 -Methyl-1,11
-Tridecadienes, 13-methyl-1,11-tridecadienes, 12-methyl-1,12-tetradecadienes,
13-methyl-1,12-tetradecadiene, 13-methyl-1,13-bentadecadiene, 14-methyl-1,
13-pentadecadiene, 4-ethylidene-6-methyl-1,6-octadiene, 4-ethylidene-7-methyl-1,6-octadiene, 4-ethylidene-3,7-dimethyl-1,6-octadiene, 4-ethylidene-5,7-
Dimethyl-1,6-octadiene, 4-ethylidene-7
-Methyl-1,7-nonadiene, 4-ethylidene-8-
Methyl-1,7-nonadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4-ethylidene-8-methyl-1,8-decadiene, 4-ethylidene-9-methyl-1,8-decadiene, 4-ethylidene-9-methyl-
1,9-undecadiene, 4-ethylidene-10-methyl-1,9-undecadiene, 4-ethylidene-10-
Methyl-1,10-dodecadien, 4-ethylidene-1
1-methyl-1,10-dodecadiene, 4-ethylidene-12-methyl-1,11-tridecadiene, 4-ethylidene-13-methyl-1,11-tridecadienene,
-Ethylidene-12-methyl-1,12-tetradecadiene, 4-ethylidene-13-methyl-1,12-tetradecadiene, 4-ethylidene-13-methyl-1,1
Linear polyenes such as 3-pentadecadiene and 4-ethylidene-14-methyl-1,13-pentadecadiene are exemplified.

Further, in the following formula (I), X is-(C
R ⁴ ₂ ) N- (where R ⁴ is the same or different,
Represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, n represents a straight chain or branched alkylene group preferably represented by a is) an integer of from 1 to 10, especially - (CH ₂₎ n- (where , N is an integer of 1 to 10). Specifically, 4-methyl-1,4
-Hexadiene, 5-methyl-1,4-hexadiene,
5-methyl-1,5-heptadiene, 6-methyl-1,5
-Heptadiene, 6-methyl-1,6-octadiene,
7-methyl-1,6-octadiene, 5,7-dimethyl-
Examples thereof include 1,6-octadiene, 8-methyl-1,7-nonadiene, and 9-methyl-1,8-decadiene, and particularly preferably, 7-methyl-1,6-octadiene is used. These non-conjugated polyenes can be used alone or in combination of two or more.

Formula (I) CH ₂ ＣＨCH—X—CR ¹ ＣＲCR ² —R ³ (wherein X represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and R ¹ and R ² represent The same or different, and represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 8 carbon atoms, unless R ¹ and R ² are both hydrogen atoms. )

(A) The iodine value of the ethylene copolymer rubber is in the range of 15 to 45, preferably 20 to 35 (the above requirement). In this case, if the iodine value is less than 15, the mechanical strength is poor, while if it exceeds 45, the rubber elasticity is impaired. Adjustment of the iodine value can be easily performed by adjusting the amount of the non-conjugated polyene or the like.

The ethylene copolymer rubber (A) preferably further has a unit derived from α, ω-diene represented by the following formula (II). Formula (II) CH ₂ ＣＨCH— (CH ₂ ) m—CH = CH ₂ (where m is an integer of 1 to 10.) Thus, α, ω-diene is combined to form (A) ethylene When a system-based copolymer rubber is produced, the molecular weight distribution of the obtained ethylene-based copolymer rubber (A) is appropriately widened and processability is improved. As the α, ω-diene, specifically,
1,5-hexadiene, 1,6-heptadiene, 1,7
-Octadiene, 1,9-decadiene, 1,10-undecadiene, 1,11-dodecadiene, 1,12-tridecadiene, 1,13-tetradecadiene and the like, preferably 1,5-hexadiene, 1,7 -Octadiene, 1,9-decadiene and the like. These α,
ω-dienes can be used alone or in combination of two or more. (A) α, ω- of the above formula (II) is added to the ethylene copolymer rubber.
When units derived from ene are included, their content is
It is desirably 0.001 to 3 mol%, preferably 0.01 to 0.3 mol%.

(A) The ethylene copolymer rubber has a Mooney viscosity (ML1 + 4, 100 ° C.) (hereinafter also referred to as “Mooney viscosity”) in the range of 25 to 350, preferably 40 to 300 (the above requirement). ). If the Mooney viscosity is less than 25, the mechanical strength of the obtained rubber vulcanizate tends to decrease, while if it exceeds 350, the processing properties of the obtained rubber composition are poor.

(A) The glass transition temperature Tg of the ethylene copolymer rubber determined by a differential scanning calorimeter (DSC) is-
It is in the range of 50 to -80C, preferably -55 to -75C (requirement).

(A) The molecular weight distribution of the ethylene copolymer rubber was determined by gel permeation chromatography (GP).
C) The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene measured in C).
Is preferably from 2.5 to 15, and more preferably from 3 to 10
It is.

The degree of branching index B of the ethylene copolymer (A)
Is 0.60 to 1.0, preferably 0.70 to 0.92
In the range. The value of the branching degree index B is represented by viscosity-GPC
According to the method (Murao Kurata, Journal of the Rubber Society of Japan, (45) 1972), the intrinsic viscosity [η ⁰ ] of the model copolymer rubber having no branching and the viscosity equation [Mw ⁰ ] obtained from polystyrene equivalent weight average molecular weight (Mw ⁰ ) [ [η ¹ ] = KMw ⁰ (where K is a constant), [η ¹ ] is calculated from Mw ¹ obtained by GPC measurement of the target copolymer rubber, and then the target copolymer weight is calculated. It was determined by dividing the actual measurement [η ² ] of the coalescence by [η ¹ ] calculated from the above viscosity equation. Here, [η ¹ ] and [η ² ] are values determined at 135 ° C. in o-dichlorobenzene, and Mw ¹ is a value determined at 135 ° C. in o-dichlorobenzene by the GPC measurement method.

The (A) ethylene copolymer rubber used in the present invention can be produced by an appropriate method such as a gas phase polymerization method, a solution polymerization method, and a slurry polymerization method. These polymerization operations can be carried out in a batch system or a continuous system. In the above solution polymerization method or slurry polymerization method, an inert hydrocarbon is usually used as a reaction medium. Such inert hydrocarbon solvents include, for example, n
-Pentane, n-hexane, n-heptane, n-octane,
aliphatic hydrocarbons such as n-decane and n-dodecane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and aromatic hydrocarbons such as benzene, toluene and xylene. These hydrocarbon solvents can be used alone or in combination of two or more. Further, the raw material monomer can be used as a hydrocarbon solvent.

Examples of the polymerization catalyst used for producing the above (A) ethylene copolymer rubber include V, Ti,
An olefin polymerization catalyst comprising a compound of a transition metal selected from Zr and Hf and an organometallic compound can be exemplified. The transition metal compound and the organometallic compound can be used alone or in combination of two or more. As a particularly preferred example of such an olefin polymerization catalyst, a metallocene catalyst comprising a metallocene compound and an organoaluminum compound or an ionic compound which reacts with the metallocene compound to form an ionic complex can be mentioned.

Next, the vulcanizing agent used in the present invention and / or
Alternatively, a crosslinking agent will be described. As the vulcanizing agent,
For example, sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur; inorganic vulcanizing agents such as sulfur chloride, selenium, and tellurium; sulfur-containing organic compounds such as morpholine disulfide, alkylphenol disulfide, thiuram disulfides, and dithiocarbamate; Is mentioned. These vulcanizing agents can be used alone or in combination of two or more. The compounding amount of the vulcanizing agent is usually 0.1 to 1 with respect to 100 parts by weight of the ethylene copolymer rubber (A).
0 parts by weight, preferably 0.5 to 5 parts by weight.

Further, a vulcanization accelerator can be used together with the vulcanizing agent. Such vulcanization accelerators include, for example, aldehyde ammonias such as hexamethylenetetramine; guanidines such as diphenylguanidine, di (o-tolyl) guanidine, o-trilupiguanide; thiocarbanilide, di (o-tolyl) ) Thioureas such as thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazole, dibenzothiazole disulfide, 2- (4-morpholinothio) benzothiazole, -(2,4-dinitrophenyl) -mercaptobenzothiazole, (N, N'-
Thiazoles such as diethylthiocarbamoylthio) benzothiazole; N-tert-butyl-2-benzothiazylsulfenamide, N, N'-dicyclohexyl-2
-Benzothiazylsulfenamide, N, N'-diisopropyl-2-benzothiazylsulfenamide, N-
Sulfenamides such as cyclohexyl-2-benzothiazylsulfenamide; thiurams such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide; dimethylthio Zinc carbamate, zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate, copper dimethyldithiocarbamate, tellurium dimethylthiocarbamate, iron dimethylthiocarbamate and the like Carbamates; xanthates such as zinc butylthioxanthate; and the like. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerator is ethylene copolymer rubber 1
The amount is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight based on 00 parts by weight.

Further, in addition to the vulcanizing agent and the vulcanization accelerator, a vulcanization accelerating auxiliary may be added as required. Examples of such vulcanization accelerators include metal oxides such as magnesium oxide, zinc white, litharge, rhododendron, and lead white, stearic acid, oleic acid, and organic acids such as zinc stearate. Particularly preferred are zinc white and stearic acid. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerator is usually 0.5 to 20 parts by weight based on 100 parts by weight of the ethylene copolymer rubber.

Further, as the crosslinking agent, for example, 1,1
Di-tert-butylperoxy-3,3,5-trimethylcyclohexane, di-tert-butyl peroxide, dicumyl peroxide, tert-butylcumyl peroxide,
Organic peroxides such as 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane and 1,3-bis (tert-butylperoxy-isopropyl) benzene are exemplified. These crosslinking agents can be used alone or in combination of two or more. The amount of the crosslinking agent
(A) It is usually 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the ethylene copolymer rubber.

Further, a crosslinking aid can be used together with the crosslinking agent. Examples of such a crosslinking aid include sulfur, sulfur compounds such as dipentamethylenethiuram tetrasulfide; ethylene di (meth) acrylate;
Other functional monomers such as polyethylene di (meth) acrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, metaphenylene bismaleimide, and toluylene bismaleimide; p-quinone oxime, p,
Oxime compounds such as p'-benzoylquinone oxime. These crosslinking assistants can be used alone or in combination of two or more. The compounding amount of the crosslinking aid is usually 0.5 to 20 parts by weight based on 100 parts by weight of the ethylene copolymer rubber (A).

The rubber composition for a weatherstrip of the present invention may contain, if desired, various other additives such as a filler, a softener, a foaming agent, a plasticizer, a lubricant, a tackifier, an antioxidant, and an ultraviolet absorber. Additives can be included. As the filler, for example, SRF, FEF, HAF, ISA
Carbon blacks such as F, SAF, FT, and MT; and inorganic fillers such as white carbon, fine-particle magnesium silicate, calcium carbonate, magnesium carbonate, clay, and talc. These fillers can be used alone or in combination of two or more. The amount of the filler is usually 10 to 200 parts by weight, preferably 10 to 10 parts by weight, based on 100 parts by weight of the ethylene copolymer rubber.
0 parts by weight.

Examples of the softening agent used in the present invention include process oils such as aromatic oils, naphthenic oils and paraffin oils usually used for rubber; vegetable oils such as coconut oil; and synthetic oils such as alkylbenzene oils. Is mentioned. Of these, process oils are preferred, and paraffin oil is particularly preferred. The softener is
They can be used alone or in combination of two or more. The blending amount of the softener is (A) ethylene copolymer rubber 1
It is usually 10 to 130 parts by weight, preferably 20 to 100 parts by weight, based on 00 parts by weight.

Examples of the foaming agent include inorganic foaming agents such as ammonium carbonate, sodium bicarbonate and anhydrous sodium nitrate; dinitropentamethylenetetramine, N,
N'-dimethyl-N, N 'dinitrosoterephthalamide, benzenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide), 3,3'-disulfone hydrazide diphenyl sulfone, azoisobutyronitrile, azobisformamide, etc. Organic foaming agents. In addition, along with these blowing agents, urea,
An organic acid-based or metal salt-based foaming aid may be used in combination.
These foaming agents and firing aids can be used alone or in combination of two or more. The compounding amount of the foaming agent is appropriately compounded according to the desired foaming density, but is usually 0.5 to 30 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of the ethylene copolymer rubber (A). Parts by weight. If the amount is less than 0.5 part by weight, the foaming is insufficient. On the other hand, if the amount exceeds 30 parts by weight, it becomes difficult to obtain a uniform foam, which causes inconvenience such as poor appearance.

Further, the rubber composition for a weather strip of the present invention contains butyl rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene / butadiene copolymer, acrylonitrile / sodium rubber as long as the object of the present invention is not impaired. Butadiene copolymer, other types of ethylene /
α-olefin / non-conjugated diene copolymer, ethylene / α
-One or more other rubbers or resins such as olefin polymers, polyethylene, and polypropylene can be used as a mixture.

In preparing the rubber composition for a weather strip of the present invention, a conventionally known kneader, extruder, vulcanizing apparatus and the like can be used. (A) The compounding method and order of the vulcanizing agent and / or crosslinking agent, filler, softening agent, foaming agent and the like mixed together with the ethylene-based copolymer rubber may be, for example, ethylene-based using a Banbury mixer or the like. After blending a copolymer rubber, a filler, a softener, and the like, a method of adding a vulcanizing agent and / or a cross-linking agent, a foaming agent, and the like using a roll or the like may be used, but the method is not limited thereto. Next, vulcanization and foaming by raising the temperature by placing the rubber composition of the present invention in a mold, or using an extruder, for example, by a method provided for the production of ordinary vulcanized rubber. After vulcanizing and foaming by heating in a vulcanizing tank after molding into an arbitrary shape, a vulcanized sponge rubber can be produced. The rubber composition for a weatherstrip of the present invention can be suitably used for applications such as sponge products for automobiles and glass runs.

[0030]

The embodiments of the present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these embodiments. The percentages and parts in the examples are on a weight basis unless otherwise specified.

The measurements and evaluations in the examples and comparative examples were performed by the following methods. (A) α-Olefin unit content (mol%) Measured by ¹³ C-NMR method. However, the content (mol%) of the ethylene unit and the α-olefin unit in each of Examples and Comparative Examples is a value when the total amount of these units is 100 mol%. (Ii) Iodine value It was measured by an infrared absorption spectrum method. (C) Mooney viscosity (ML1 + 4,100 ° C.) Measured at a measurement temperature of 100 ° C., a preheating time of 1 minute, and a measurement time of 4 minutes in accordance with JIS K6300. (D) Measured by GPC in Mw / Mn o-dichlorobenzene at 135 ° C.

(E) Glass transition temperature Tg Using a 910 type differential scanning calorimeter manufactured by DuPont Instruments (currently TIA Instruments),
The sample was heated to 180 ° C., then cooled at a rate of 10 ° C./min to −90 ° C., and measured while heating at a rate of 20 ° C./min. (F) Branching index B 0-dichlorobenzene, sample concentration 0.15% by weight, 1
Under the condition of 35 ° C., Waters 150CV type GPC
Was measured by (G) Vulcanization property test Using a Curastometer-V type manufactured by Nippon Synthetic Rubber Co., Ltd. (currently JSR Corporation), a torque maximum value and a minimum torque are obtained from a vulcanization curve at 190 ° C. for 30 minutes. 90 of the difference from the value
% (T ₉₀ ) and 10% (t ₁₀ ), and the difference t ′ _c (d80) = t _90.
It was evaluated by the -t _10. The smaller the t ' _c (d80), the faster the vulcanization rate.

(H) Tensile test In accordance with JIS K6301, a No. 3 type test piece was used at a measuring temperature of 25 ° C. and a tensile speed of 500 mm / min, and a tensile strength TB (MPa) and an elongation at break EB ( %) Was measured. (I) Hardness test According to JIS K6301, the spring hardness (JIS
-A hardness) was measured. (G) Compression set In accordance with JIS K6301, the compression set was measured at 70 ° C. for 22 hours. (R) Low-temperature torsion test (Gaeman temperature) T10 (° C.) was measured in accordance with JIS K6301.

Synthesis Example 1 (Synthesis of Ethylene Copolymer Rubber) In a stainless steel autoclave having a capacity of 3 liters and sufficiently purged with nitrogen, 1.7 liters of purified toluene, 150 g of 1-butene, 7-methyl-1,6 -Octadiene 50
After adding milliliter and raising the temperature to 50 ° C., 52 NL of ethylene and 10 NL of hydrogen were charged. Separately from this, the contents of the container with a sufficient nitrogen replacement and a magnetic stirrer are added.
Purified toluene in a milliliter glass flask.
1.0 μmol of diphenylmethylene (fluorenyl) (cyclopentadienyl) zirconium dichloride dissolved in 0 ml and 0.5 mmol of triisobutylaluminum dissolved in 6.0 ml of purified toluene are stirred at room temperature for 30 minutes. And reacted. Next, 1.8 μmol of dimethylanilinium tetrakis (pentafluorophenyl) borate dissolved in 7.2 ml of purified toluene was added, and the mixture was stirred at room temperature for 20 minutes to be reacted to obtain a polymerization catalyst.

The polymerization catalyst was added to the autoclave to start polymerization. During the reaction, the temperature was maintained at 50 ° C., and polymerization was performed for 15 minutes. Next, a small amount of methanol was added to stop the reaction, and then the mixture was dissolved by steam stripping and dried with a 6-inch roll to obtain 90 g of a polymer. This polymer has an ethylene unit content of 7
2 mol%, 1-butene unit content: 28 mol%, iodine value: 19, Mooney viscosity: 50, Mw / Mn: 2.1,
It was an ethylene / 1-butene / 7-methyl-1,6-octadiene copolymer having a Tg of -66.8 ° C. and a branching index B of 0.99. This copolymer is designated as (A-1).

Example 1 (Preparation and evaluation of rubber composition) Ethylene copolymer rubber (A-1) was prepared by adding each component obtained by removing a vulcanizing agent component from the components shown in Table 2 to a Labo Plastomill (content 250 (Milliliter), rotation speed 60 rpm, 6
The mixture was kneaded at 0 ° C. for 150 seconds to obtain a compound (i). Next, the remaining vulcanizing agent components shown in Table 2 were added to compound (i), and kneaded with a 10-inch roll maintained at 50 ° C for 5 minutes to obtain compound (ii). Then, the compound (ii) is heated by a hot press heated to 160 ° C. under a pressure of 150 kgf / cm ² for 30 minutes to obtain a vulcanized sheet of 120 × 120 × 2 mm and a sample for compression set test. Were prepared and various characteristics were evaluated. Table 3 shows the evaluation results. From the results shown in Table 3, the vulcanized product of the rubber composition using the ethylene copolymer rubber (A-1) has an excellent balance of compression set, mechanical strength, and low-temperature properties. it is obvious.

Examples 2 and 3 (Preparation and Evaluation of Rubber Composition) Ethylene copolymer rubbers (A-2) and (A) shown in Table 1 were prepared in the same manner as in the polymerization method shown in Synthesis Example 1. -3)
Was synthesized, and the rubber composition was adjusted and evaluated according to the same formulation as in Example 1. Table 3 shows the evaluation results. From the results shown in Table 3, these ethylene copolymer rubbers (A-
It is apparent that the vulcanized product of the rubber composition using (2) and (A-3) has an excellent balance of compression set, mechanical strength, and low-temperature properties.

Comparative Examples 1 and 2 (Preparation and Evaluation of Rubber Composition) Ethylene copolymer rubbers (C-1) and (C) shown in Table 1 were prepared in substantially the same manner as the polymerization method shown in Synthesis Example 1. −
2) was synthesized, and a rubber composition was prepared and evaluated according to the same formulation as in Example 1. Table 3 shows the evaluation results. Table 3
From the results shown in the above, the composition of Comparative Example 1 using the ethylene copolymer rubber (C-1) as EPDM was inferior in compression set and slow in vulcanization rate. It is clear that the rubber composition of Comparative Example 2 using the ethylene copolymer rubber (C-2) synthesized by copolymerizing 1-octene instead of 1-butene has poor mechanical strength. .

[0039]

[Table 1] (*) MOCD: 7-methyl 1,6-octadiene (**) DD: 1,9-decadiene

[0040]

[Table 2] (* 1): Seast G116 manufactured by Tokai Carbon Co., Ltd. (* 2): PW-380 manufactured by Idemitsu Kosan Co., Ltd. (* 3): Mercaptobenzothiazole (* 4): Tetramethylthiuram disulfide

[0041]

[Table 3]

[0042]

The vulcanizates of the rubber compositions for weather strips of the present invention have an excellent balance of compression set, mechanical strength and low-temperature properties. Therefore, the rubber composition for a weatherstrip of the present invention has high properties as a material for a weatherstrip such as a sponge part of an automobile and a glass run.

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[Procedure amendment]

[Submission date] September 3, 1998 (1998.9.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

[0039]

[Table 1] (*) MOCD: 7-methyl-1,6-octadiene (**) DD: 1,9-decadiene

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Fumio Tsutsumi Inventor of JSR Co., Ltd.

Claims (3)

[Claims] (A) a unit derived from ethylene, 1-
It has a unit derived from butene and a unit derived from a non-conjugated polyene, and contains, as main components, an ethylene copolymer rubber satisfying the following requirements and (B) a vulcanizing agent and / or a crosslinking agent. A rubber composition for a weatherstrip. Requirements The molar ratio (ethylene / 1-butene) of the unit derived from ethylene to the unit derived from 1-butene is 20/80.
８５85/15 Iodine value 15〜45 Mooney viscosity (ML1 + 4, 100 ° C.) 25２５350
The glass transition temperature (Tg) determined by a differential scanning calorimeter (DSC) is −50 ° C. to −80 ° C. 2. The weatherstrip according to claim 1, wherein the non-conjugated polyene in the (A) ethylene copolymer rubber is a chain non-conjugated polyene represented by the following formula (I). Rubber composition. Formula (I) CH ₂ ＣＨCH—X—CR ¹ ＣＲCR ² —R ³ (wherein, X represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and R ¹ and R ² are the same or different. Differently, it represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 8 carbon atoms, except that both R ¹ and R ² are hydrogen atoms.) 3. The rubber for weather strip according to claim 2, wherein (A) the ethylene copolymer rubber further contains a unit derived from α, ω-diene represented by the following formula (II). Composition. Formula _{(II) CH 2 = CH- (} CH 2) m-CH = CH 2 ( wherein, m is an integer of from 1 to 10.)