JP2000072935A5 - - Google Patents

Description

0002.
[Conventional technology]
Conventionally, ethylene / α-olefin / non-conjugated diene copolymers have excellent weather resistance, heat resistance, cold resistance, ozone resistance, etc., and are widely used in building materials, automobile parts, electric wire covering materials, and the like. .. In particular, in order to provide soundproofing and waterproofing inside and outside the automobile, many parts mainly composed of ethylene / propylene / non-conjugated diene copolymer rubber (hereinafter, also referred to as EPDM) are used around doors and trunk rooms. Rubber is used. However, conventional EPDM has a slow vulcanization rate, and when a large amount of vulcanization accelerator is added to the EPDM formulation in order to increase the vulcanization rate, the vulcanization accelerator appears on the surface of the product, which is a so-called blooming problem. Occurs. In addition, conventional EPDM is not satisfactory in terms of physical properties such as settling resistance.

0006
[Means for solving problems]
According to the present invention, the following rubber composition for weather strip is provided, and the above object of the present invention is achieved.
(1) (A) An ethylene-based 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 [1] to [4]. A rubber composition for a weather strip, which comprises (B) a vulcanizing agent and / or a cross-linking agent as a main component.
Requirements
[1] The molar ratio (ethylene / 1-butene) of the unit derived from ethylene and the unit derived from 1-butene is 20/80 to 85/15.
[2] The iodine value is 15 to 45.
[3] Mooney viscosity (ML1 + 4,100 ° C.) is 25 to 350.
[4] 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 above (A) ethylene-based copolymer rubber has the following formula. The rubber composition for a weather strip according to (1) above, which is a chain non-conjugated polyene represented by (I).
Equation (I)
CH ₂ = CH-X-CR ¹ = CR ^2- R ³
(Wherein, X represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, R ^1, R ² are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ³ indicates an alkyl group having 1 to 8 carbon atoms, except when both ^{R 1} and R ^{2 are hydrogen atoms.)}
(3) The rubber for weather strip according to (2) above, wherein the ethylene-based copolymer rubber further contains a unit derived from α, ω-diene represented by the following formula (II). Composition.
Equation (II)
CH ₂ = CH − (CH ₂ ) _m − CH = CH ₂
(In the formula, m is an integer of 1 to 10.)

0007
BEST MODE FOR CARRYING OUT THE INVENTION
The (A) ethylene-based copolymer rubber used in the rubber composition of the present invention is a unit derived from ethylene, 1-butene, and a non-conjugated polyene (hereinafter, "ethylene unit", "1-butene unit", and "1-butene unit", respectively. It is a copolymerized rubber having a "non-conjugated polyene unit"). (A) The molar ratio (ethylene / 1-butene) of the ethylene unit to the 1-butene unit in the ethylene-based copolymer rubber is 20/80 to 85/15, preferably 30/70 to 82/18, more preferably. It is 50/50 to 80/20 (the above requirement [1] ). When the molar ratio is in the above range, the mechanical strength and the compression set are maintained in a well-balanced manner, which is preferable.

Examples of non-conjugated polyenes include 5-ethylidene-2-norbornene, dicyclopentadiene, 5-propyriden-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene, and 1,4-cyclohexadiene. Cyclic polyenes such as 1,4-cyclooctadiene and 1,5-cyclooctadiene, 1,4-hexadiene, 1,5-heptadiene, 1,6-octadene, 1,7-nonadien, 1,8-decadien and the like. Chain diene can be mentioned.

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 and 5-methyl-1,4. -Hexadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadene, 3,7-dimethyl-1 , 6-octadene, 5,7-dimethyl-1,6-octadene, 7-methyl-1,7-nonadene, 8-methyl-1,7-nonadene, 8-methyl-1,8-decadene, 9-methyl -1,8-decadene, 9-methyl-1,9-undecadiene, 10-methyl-1,9-undecadiene, 10-methyl-1,10-dodecadiene, 11-methyl-1,10-dodecadiene, 12-methyl -1,11-Tridecadien, 13-Methyl-1,11-Tridecadien, 12-Methyl-1,12-Tetradecadene, 13-Methyl-1,12-Tetradecadene, 13-Methyl-1,13- Pe printer decadiene, 14-methyl-1,13-penta decadiene, 4-ethylidene-6-methyl-1,6-octadiene, 4-ethylidene-7-methyl-1,6-octadiene, 4-ethylidene-3,7 −Diene-1,6-octadiene, 4-ethylidene-5,7-dimethyl-1,6-octadene, 4-ethylidene-7-methyl-1,7-nonadiene, 4-ethylidene-8-methyl-1,7 -Nonadiene, 4-Etilidene-8-Methyl-1,7-Nonadiene, 4-Echilidene-8-Methyl-1,8-Decadien, 4-Echilidene-9-Methyl-1,8-Decadien, 4-Echiliden-9 -Methyl-1,9-undecadiene, 4-ethylidene-10-methyl-1,9-undecadiene, 4-ethylidene-10-methyl-1,10-dodecadiene, 4-ethylidene-11-methyl-1,10-dodecadiene , 4-Echilidene-12-Methyl-1,11-Tridecadien, 4-Echilidene-13-Methyl-1,11-Tridecadien, 4-Echilidene-12-Methyl-1,12-Tetradecadene, 4-Echilidene-13 Examples thereof include chain polyenes such as −methyl-1,12-tetradecadiene, 4-ethylidene-13-methyl-1,13-pentadecadiene, and 4-ethylidene-14-methyl-1,13-pentadecadiene. ..

Further, in the following formula (I), X is ^{_{- (CR 4 2) n -}} ( wherein, R ⁴ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, n represents 1 A linear or branched alkylene group represented by (an integer of 10) is preferable, and a linear alkylene group represented by − (CH ₂ ) _n − (where n is an integer of 1 to 10) is preferable. Is preferable. 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-octadien, 7-methyl-1,6-octadien, 5,7-dimethyl-1,6-octadien, 8-methyl-1,7-nonadien, 9-methyl-1,8-decadien. Particularly preferably, 7-methyl-1,6-octadien is used. These non-conjugated polyenes can be used alone or in combination of two or more.

Equation (I)
CH ₂ = CH-X-CR ¹ = CR ^2- R ³
(Wherein, X represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, R ^1, R ² are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ³ indicates an alkyl group having 1 to 8 carbon atoms, except when both ^{R 1} and R ^{2 are hydrogen atoms.)}

The iodine value of the ethylene-based copolymer rubber (A) is in the range of 15 to 45, preferably 20 to 35 (the above requirement [2] ). In this case, if the iodine value is less than 15, the mechanical strength is inferior, while if it exceeds 45, the rubber elasticity is impaired. The iodine value can be easily adjusted by adjusting the amount of non-conjugated polyenes and the like.

Further, it is preferable that the ethylene-based copolymer rubber (A) further has a unit derived from α, ω-diene represented by the following formula (II).
Equation (II)
CH ₂ = CH − (CH ₂ ) _m − CH = CH ₂
(In the formula, m is an integer of 1 to 10.)
When the (A) ethylene-based copolymer rubber is produced by combining α and ω-diene in this way, the molecular weight distribution of the obtained (A) ethylene-based copolymer rubber is appropriately widened, and the processability is improved.
Specific examples of α and ω-diene include 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,9-decadien, 1,10-undecadien, 1,11-dodecadien, and 1 , 12-Tridecadien, 1,13-Tetradecadien and the like, preferably 1,5-hexadiene, 1,7-octadien, 1,9-decadien and the like. These α and ω-dienes can be used alone or in combination of two or more.
(A) When the ethylene-based copolymer rubber contains a unit derived from α, ω-diene of the above formula (II), the content thereof is 0.001 to 3 mol%, preferably 0.01 to 0.3. It is preferably mol%.

(A) The Mooney viscosity (ML1 + 4,100 ° C.) of the ethylene-based copolymer rubber (hereinafter, also simply referred to as “Moony viscosity”) is in the range of 25 to 350, preferably 40 to 300 (the above requirement [3]. ] ). If the Mooney viscosity is less than 25, the mechanical strength of the obtained rubber composition tends to decrease, while if it exceeds 350, the processing characteristics of the obtained rubber composition are inferior.

Further, the glass transition temperature Tg determined by (A) differential scanning calorimetry (DSC) of the ethylene copolymer rubber is in the range of −50 ° C. to −80 ° C., preferably −55 ° C. to −75 ° C. (the above requirements). [4] ).

The ethylene-based copolymer rubber (A) used in the present invention can be produced by an appropriate method such as a vapor phase polymerization method, a solution polymerization method, or a slurry polymerization method. These polymerization operations can be carried out in batch or continuous manner. In the above solution polymerization method or slurry polymerization method, an inert carbon is usually used as the reaction medium. Examples of such an inert hydrocarbon solvent include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane, n-decane, and n-dodecane; and fats such as cyclohexane and methylcyclohexane. Cyclic hydrocarbons; examples include aromatic hydrocarbons such as benzene, toluene and xylene. These hydrocarbon solvents can also be used alone or in admixture of two or more. Further, the raw material monomer can also be used as a hydrocarbon solvent.

Next, the (B) vulcanizing agent and / or the cross-linking agent used in the present invention will be described.
Examples of the sulfurizing agent include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur; inorganic sulphurizing agents such as sulfur chloride, selenium, and tellurium; morpholini disulfide, alkylphenol disulfide, thiuram disulfides, and dithiocarbamate. Examples include sulfur-containing organic compounds such as. These vulcanizers can be used alone or in admixture of two or more. The blending amount of the vulcanizing agent is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the (A) ethylene-based copolymer rubber.

Further, a vulcanization accelerator can be used in combination with the vulcanization agent. Examples of such a sulfide accelerator include aldehyde ammonias such as hexamethylenetetramine; guanidines such as diphenylguanidine, di (o-tolyl) guanidine, and o-trilupiguanide; thiocarbanilide and di (o-tolyl). ) Thioureas such as thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazol, dibenzothiazole disulfide, 2- (4-morpholinothio) benzothiazole, 2 -(2,4-Dinitrophenyl) -mercaptobenzothiazol, (N, N'-diethylthiocarbamoylthio) thiazoles such as benzothiazole; N-tertiary butyl-2-benzothiazil sulphenamide , N, N'-dicyclohexyl-2-benzothiazil sulphenamide, N, N'-diisopropyl-2-benzothiazil sulphenamide, N-cyclohexyl-2-benzothiazil sulphenamide Classes: Thiurams such as tetramethylthium disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram tetrasulfide; zinc dimethyl thiocarbamate, zinc diethyl thiocarbamate, di-n-butyl zinc thiocarbamate, ethylphenyl dithiocarbamate, zinc dimethyl dithiocarbamate sodium, dimethyldithiocarbamate, copper dimethyl thiocarbamate tellurium carbamate salts such as dimethyl thiocarbamate iron; butyl xanthate salts such as thio xanthate zinc, Can be mentioned. These vulcanization accelerators can be used alone or in admixture of two or more. The blending amount of the vulcanization accelerator is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the (A) ethylene-based copolymer rubber.

Further, in addition to the vulcanization agent and the vulcanization accelerator, a vulcanization acceleration aid can be added as needed. Examples of such a vulcanization accelerator include metal oxides such as magnesium oxide, zinc oxide, litharge, lead tan, and lead white, and organic acids such as stearic acid, oleic acid, and zinc stearate. In particular, zinc oxide and stearic acid are preferable. These vulcanization accelerating aids can be used alone or in admixture of two or more. The blending amount of the vulcanization accelerating aid is usually 0.5 to 20 parts by weight with respect to 100 parts by weight of the (A) ethylene-based copolymer rubber.

The rubber composition for weather strips of the present invention contains, if desired, fillers, softeners, foaming agents, as well as various other additives such as plasticizers, lubricants, tackifiers, anti-aging agents, and UV absorbers. Can be blended.
Examples of the filler include carbon black such as SRF, FEF, HAF, ISAF, SAF, FT and MT; and inorganic fillers such as white carbon, fine particle magnesium silicate, calcium carbonate, magnesium carbonate, clay and talc. Be done. These fillers can be used alone or in admixture of two or more. The blending amount of the filler is usually 10 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the ethylene copolymer rubber (A).

As the foaming agent, for example, ammonium carbonate, sodium bicarbonate, inorganic blowing agent such as anhydrous sodium nitrate; dinitropentamethylenetetramine, N, N'-dimethyl -N, N '- dinitrosoterephthalamide, benzenesulfonyl hydrazide, Examples thereof include organic foaming agents such as p, p'-oxybis (benzenesulfonyl hydrazide), 3,3'-disulfone hydrazidediphenylsulfone, azoisobutyronitrile, and azobisformamide. In addition to these foaming agents, foaming aids such as urea-based, organic acid-based, and metal salt-based foaming agents may be used in combination. These foaming agents and foaming aids can be used alone or in admixture of two or more.
The amount of the foaming agent to be blended is appropriately blended according to the desired foaming density, but is usually 0.5 to 30 parts by weight, preferably 1 to 15 parts by weight with respect to 100 parts by weight of (A) ethylene-based copolymer rubber. It is a part by weight. If it is less than 0.5 parts by weight, foaming is insufficient, while if it exceeds 30 parts by weight, it becomes difficult to obtain a uniform foam, and inconveniences such as poor appearance occur.

The measurements and evaluations in the examples and comparative examples were carried out by the following methods.
(A) Α-olefin unit content (mol%)
¹³ Measured by C-NMR method. However, the content (mol%) of the ethylene unit and the α-olefin unit in each Example and Comparative Example shows a value when the total amount thereof is 100 mol%.
(B) Iodine value Measured by infrared absorption spectroscopy.
(C) Mooney viscosity (ML1 + 4, 100 ° C)
According to JIS K6300, the measurement was performed under the conditions of a measurement temperature of 100 ° C., preheating for 1 minute, and measurement for 4 minutes.
(D) Mw / Mn
Measured by GPC under the condition of 135 ° C. in o-dichlorobenzene.

Synthesis Example 1 (Synthesis of ethylene-based copolymer rubber)
1.7 liters of purified toluene, 150 grams of 1-butene, and 50 ml of 7-methyl-1,6-octadien were added to a fully nitrogen-substituted stainless steel autoclave with a content of 3 liters, the temperature was raised to 50 ° C., and then ethylene was used. Was charged with 52 NL and hydrogen was charged with 10 NL. Separately, diphenylmethylene (fluorenyl) (cyclopentadienyl) zirconium dichloride dissolved in 3.0 ml of purified toluene in a glass flask with a content of 50 ml containing a magnetic stir bar after sufficient nitrogen substitution. 0.5 mmol of triisobutylaluminum dissolved in 1.0 μmol and 6.0 ml of purified toluene was added, and the mixture was stirred and reacted at room temperature for 30 minutes. Next, 1.8 μmol of dimethylanilinium tetrakis (pentafluorophenyl) borate dissolved in 7.2 ml of purified toluene was added, and the mixture was stirred and reacted at room temperature for 20 minutes to prepare a polymerization catalyst.

This polymerization catalyst was added to the autoclave to initiate polymerization. During the reaction, the temperature was kept at 50 ° C. and polymerization was carried out for 15 minutes. A small amount of methanol was then added to stop the reaction, which was then desolubilized by steam stripping and dried on a 6 inch roll to give 90 g of polymer. This polymer has ethylene unit content: 72 mol%, 1-butene unit content: 28 mol%, iodine value: 19, Mooney viscosity: 50, Mw / Mn: 2.1, Tg: -66.8 ° C, degree of branching. It was an ethylene / 1-butene / 7-methyl-1,6-octadien copolymer having an index B: 0.99. Let this copolymer be (A-1).

（＊）ＭＯＣＤ：７−メチル１，６−オクタジエン
（＊＊）ＤＤ：１，９−デカジエン
（＊＊＊）ＥＮＢ：５−エチリデン−２−ノルボルネン

(*) MOCD: 7-methyl 1,6-octadien (**) DD: 1,9-decadien
(***) ENB: 5-Etylidene-2-Norbornene

Claims (3)

(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 [1] to [4] ; ) A rubber composition for a weather strip, which contains a vulcanizing agent and / or a crosslinking agent as a main component.
Requirement
[1] The molar ratio (ethylene / 1-butene) of units derived from ethylene and units derived from 1-butene is 20/80 to 85/15
[2] The iodine value is 15 to 45
[3] Mooney viscosity (ML1 + 4, 100 ° C.) is 25 to 350
[4] The glass transition temperature (Tg) determined by a differential scanning calorimeter (DSC) is −50 ° C. to −80 ° C. The rubber composition for a weather strip 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).
Formula (I)
_{CH 2 = CH-X-CR} 1 = CR 2 -R 3
(Wherein, X represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, R ^1, R ² are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ³ represents an alkyl group having 1 to 8 carbon atoms, except when R ¹ and R ² are both hydrogen atoms. The rubber composition for a 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).
Formula (II)
_{CH 2 = CH- (CH 2)} m -CH = CH 2
(In the formula, m is an integer of 1 to 10.)