JP2004043824A - Wiper blade rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing rubber parts which is considerably improved in the cold temperature flexibility without damaging the excellent thermal aging resistance and weatherability which an EPDM originally possesses and to provide a wiper blade rubber which is excellent in the flexibility at low temperatures and rubber elasticity. <P>SOLUTION: The wiper blade rubber comprises a composition which contains a random copolymer rubber consisting of ethylene, a 3-20C α-olefin and a branched-chain polyene compound such as 4-ethylidene-8-methyl-1, 7-nonadiene or the like; a vulcanizing agent; and a filler, with the above copolymer rubber having a molar ratio of ethylene to α-olefin, an iodine value and a limiting viscosity each within a specified range. The above wiper blade rubber has an excellent cold temperature flexibility and excellent wiping effect even under such a cold environment as 0°C or below. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a seal rubber part and a wiper blade rubber, and more particularly to a seal rubber part and a wiper blade rubber which are particularly excellent in low-temperature flexibility.

Ethylene / propylene / non-conjugated diene copolymer rubber (hereinafter sometimes referred to as EPDM) is excellent in heat aging resistance, weather resistance, water resistance, chemical resistance, low temperature properties and flexibility, and is therefore suitable for household use. In addition to sealing rubber parts such as jar packing, sealing material at the joint between glass and sash, and sealing material for window frames for automobiles, in recent years, cups for brake master cylinders and brake wheel cylinders for hydraulic brakes It is known to be used as a sealing material for hydraulic cylinders of automobiles, such as cups.

Conventionally, it has been known that styrene-butadiene rubber is mainly used as a sealing material for a hydraulic cylinder. However, in recent years, as the performance of automobiles has improved, the temperature in the engine room has increased, and styrene / butadiene rubber has been thermally degraded, and is no longer a preferable seal material. Thus, EPDM has recently become the mainstream in place of styrene-butadiene rubber.

The composition for a seal rubber component disclosed in Patent Document 1 is also one example thereof.
(A) an ethylene content of 58 to 72 mol%,
(B) the product of the maximum tensile stress (RS [kgf / cm ² ] and the elongation at break (ε [%]) is 1 × 10 ^{3 to} 20 × 10 ³ ;
(C) Mooney viscosity [ML _{1 + 4} (100 ° C.)] is 20 to 50,
(D) A composition for a seal rubber part formed from a peroxide vulcanizate of an ethylene / α-olefin / diene copolymer rubber having an iodine value of 5 to 35 is described.

However, although the seal rubber component disclosed in Patent Document 1 has good low-temperature flexibility, it does not yet have satisfactory low-temperature flexibility, and there is still room for improvement.

On the other hand, EPDM is used for automobile parts by taking advantage of its excellent weather resistance. Among such automotive parts applications, wiper blade rubber is required to exhibit good flexibility in a wide temperature range, particularly at low temperatures. Further, in order to increase the productivity, the composition for wiper blade rubber is required to have high-speed vulcanizability.

However, 5-ethylidene-2-norbornene (hereinafter sometimes referred to as ENB), which has been used as the third component in the conventional EPDM, hinders the movement of the molecular chain due to its structure, and therefore cannot be used at a low temperature. There is a problem that flexibility is adversely affected. In addition, when the ENB content is reduced to improve low-temperature flexibility, there is a problem that the vulcanization rate is reduced and productivity is reduced.

Therefore, the appearance of seal rubber parts with remarkably improved low-temperature flexibility without impairing the inherently excellent heat aging resistance and weather resistance of EPDM, and wiper blade rubber with excellent low-temperature flexibility and rubber elasticity have been conventionally used. More desired.
JP-A-1-268743

The present invention is intended to solve the problems associated with the prior art as described above, and significantly improves the low-temperature flexibility without impairing the excellent heat aging resistance inherent in EPDM, weather resistance, and the like. It is intended to provide a sealed rubber part.

Another object of the present invention is to provide a wiper blade rubber excellent in low-temperature flexibility and rubber elasticity.

The wiper blade rubber according to the present invention,
A random copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and at least one kind of branched polyene compound represented by the following general formula [I];
Vulcanizing agent (B) and filler (C)
Formed of a rubber composition containing
The random copolymer rubber (A)
(I) the molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) is in the range of 55/45 to 75/25;
(Ii) the iodine value is in the range of 5 to 30,
(Iii) The intrinsic viscosity [η] measured in decalin at 135 ° C. is in a range represented by 0.5 dl / g <[η] <5.0 dl / g.

[In the formula [I], n is an integer of 1 to 5,
R ¹ is an alkyl group having 1 to 5 carbon atoms,
R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ]

The random copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms and the above-mentioned branched polyene compound used in the present invention has a molar ratio of ethylene to α-olefin, iodine value Further, since the intrinsic viscosity [η] is in a specific range, a vulcanized rubber having excellent low-temperature flexibility can be provided, and the vulcanization speed is high and high-speed molding is possible. Further, the random copolymer rubber (A) is excellent in properties such as weather resistance, ozone resistance and heat aging resistance.

Since the seal rubber part according to the present invention is formed of a composition containing the random copolymer rubber (A), the vulcanizing agent (B), and the filler (C), the heat aging resistance And has excellent weather resistance and low temperature flexibility. In particular, a seal rubber part formed of a composition for a seal rubber part using an organic peroxide as the vulcanizing agent (B) is excellent in heat aging resistance, weather resistance, water resistance, chemical resistance and the like and has low-temperature flexibility. Are better.

The seal rubber component according to the present invention having the above-mentioned effects is, specifically, a cup for a brake master cylinder, a cup for a brake wheel cylinder, a seal material for a brake fluid pressure control, and an O-ring for a brake in a hydraulic brake. It can be widely used for applications such as clutch cylinder cups in clutches.

Moreover, since the wiper blade rubber according to the present invention is formed of a composition containing the random copolymer rubber (A), the vulcanizing agent (B), and the filler (C), Excellent low temperature flexibility.

(4) The wiper blade rubber according to the present invention, which has excellent low-temperature flexibility, has an excellent wiper effect even in a cold environment of 0 ° C. or less.

Hereinafter, the seal rubber component and the wiper blade rubber according to the present invention will be specifically described.

The seal rubber component and the wiper blade rubber according to the present invention are formed of a composition containing a specific random copolymer rubber (A), a vulcanizing agent (B), and a filler (C).
Random copolymer rubber (A)
The ethylene copolymer rubber (A) used in the present invention comprises ethylene, an α-olefin having 3 to 20 carbon atoms, and a branched polyene compound.

As such α-olefin having 3 to 20 carbon atoms, specifically,
Propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl- 1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1- Dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like. Among them, propylene, 1-butene, 1-hexene and 1-octene are preferably used.

These α-olefins can be used alone or in combination of two or more.

分岐 Further, the branched polyene compound is represented by the following general formula [I].

In the formula [I], n is an integer of 1 to 5, R ¹ is an alkyl group having 1 to 5 carbon atoms, and R ² and R ³ are each independently a hydrogen atom or a carbon atom having 1 carbon atom. To 5 alkyl groups.

As the alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl Group, n-pentyl group, i-pentyl group and the like.

Examples of such a branched polyene compound (hereinafter, also referred to as a branched polyene compound [I]) include compounds specifically exemplified in the following (1) to (24). Among them, the branched polyene compounds (5), (6), (9), (11), (14), (19) and (20) are preferably used.
(1) 4-ethylidene-1,6-octadiene (2) 7-methyl-4-ethylidene-1,6-octadiene (3) 7-methyl-4-ethylidene-1,6-nonadiene (4) 7-ethyl -4-ethylidene-1,6-nonadiene (5) 6,7-dimethyl-4-ethylidene-1,6-octadiene (6) 6,7-dimethyl-4-ethylidene-1,6-nonadiene (7) 4 -Ethylidene-1,6-decadiene (8) 7-methyl-4-ethylidene-1,6-decadiene (9) 7-methyl-6-propyl-4-ethylidene-1,6-octadiene (10) 4-ethylidene -1,7-Nonadiene (11) 8-methyl-4-ethylidene-1,7-nonadiene (EMN)
(12) 4-ethylidene-1,7-undecadiene (13) 8-methyl-4-ethylidene-1,7-undecadiene (14) 7,8-dimethyl-4-ethylidene-1,7-nonadiene (15) 7 , 8-Dimethyl-4-ethylidene-1,7-decadiene (16) 7,8-dimethyl-4-ethylidene-1,7-undecadiene (17) 8-methyl-7-ethyl-4-ethylidene-1,7 -Undecadiene (18) 7,8-diethyl-4-ethylidene-1,7-decadiene (19) 9-methyl-4-ethylidene-1,8-decadiene (20) 8,9-dimethyl-4-ethylidene-1 , 8-Decadiene (21) 10-methyl-4-ethylidene-1,9-undecadiene (22) 9,10-dimethyl-4-ethylidene-1,9-undecadiene (23) 11-methyl-4-ethylidene-1 , 10-Dodecadiene (24) 10,11-dimethyl-4-ethylidene-1,10-dodecadiene These can be used alone or in combination of two or more.

分岐 The branched polyene compound [I] may be a mixture of a trans form and a cis form, or may be a trans form alone or a cis form alone.

Such a branched polyene compound can be prepared by the method described in Japanese Patent Application No. 6-154952 filed by the present applicant.

That is, it can be produced by reacting a compound having a conjugated diene represented by the following [Ia] with ethylene in the presence of a catalyst comprising a transition metal compound and an organoaluminum compound.

(Wherein [I-a], n, R ^1, R ² and R ³ are the same as n, R ^1, R ² and R ³ in the general formula [I] in which each described above.)
In the random copolymer rubber (A) used in the present invention, the structural units derived from the monomers of ethylene, α-olefin and branched polyene compound as described above are randomly arranged and bonded. The main chain has a substantially linear structure while having a branched structure caused by the branched polyene compound.

The fact that the copolymer rubber has a substantially linear structure and does not substantially contain a gel-like crosslinked polymer means that the copolymer rubber is dissolved in an organic solvent and substantially contains an insoluble component. It can be confirmed by the absence. For example, when the intrinsic viscosity [η] is measured, it can be confirmed that this copolymer rubber is completely dissolved in decalin at 135 ° C.

In addition, in such a random copolymer rubber (A), the structural unit derived from the branched polyene compound has a structure substantially represented by the following formula [II].

Wherein [II], n, R ^1, R ² and R ³ are the same in the general formula [I] in which each aforementioned n, and R ^1, R ² and R ^3. ]
The fact that the structural unit derived from the branched polyene compound has the above structure can be confirmed by measuring the ¹³ C-NMR spectrum of the copolymer.

ラ ン ダ ム The random copolymer rubber (A) used in the present invention has the following composition and properties.

(I) The random copolymer rubber (A) constituting the composition for seal rubber parts has a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) of 50/50 to 75. / 25, preferably in the range of 55/45 to 73/27.

When a random copolymer rubber (A) having a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms in the above range is used, excellent mechanical strength and excellent low-temperature flexibility are obtained. A composition capable of providing a sealing rubber part is obtained.

The random copolymer rubber (A) constituting the wiper blade rubber composition has a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) of 55/45 to 75. / 25, preferably in the range of 60/40 to 73/27.

The use of the random copolymer rubber (A) having a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms in the above range provides a wiper blade rubber excellent in low-temperature flexibility. And a composition having excellent crosslinking efficiency with an organic peroxide can be obtained.

(Ii) The random copolymer rubber (A) constituting the composition for seal rubber parts has an iodine value of 5 to 40, preferably 7 to 35. When a random copolymer rubber (A) having an iodine value in the above range is used, it is possible to provide a sealing rubber part having excellent low-temperature flexibility and a small compression set and a small tensile elongation. A fast composition is obtained.

ラ ン ダ ム The random copolymer rubber (A) constituting the wiper blade rubber composition has an iodine value of 5 to 30, preferably 7 to 25. When the random copolymer rubber (A) having an iodine value in the above range is used, a composition having a high vulcanization rate which can provide a wiper blade rubber having excellent low-temperature flexibility can be obtained.

EPDM in which the polyene component is 4-ethylidene-8-methyl-1,7-nonadiene (hereinafter sometimes abbreviated as EMN), and polyene component in which the polyene component is 5-ethylidene -2- Compared with norbornene (hereinafter sometimes abbreviated as ENB) EPDM (hereinafter sometimes abbreviated as ENB-EPDM) at the same iodine value, EMN-EPDM has a higher vulcanization rate. Is more than twice as fast.

ＥＮEven if ENB-EPDM has a high polyene content, if the polyene content exceeds 4 mol%, the effect of improving the vulcanization rate is lost. On the other hand, EMN-EPDM can increase the vulcanization rate in proportion to the polyene content until the polyene content is 7 mol%.

(4) When the iodine value of ENB-EPDM is increased in order to increase the vulcanization rate, the low-temperature flexibility deteriorates proportionately. On the other hand, EMN-EPDM has excellent low-temperature flexibility regardless of its iodine value.

(Iii) The random copolymer rubber (A) constituting the composition for seal rubber parts has an intrinsic viscosity [η] of 1.2 dl / g <[η] <3.5 dl / when measured in decalin at 135 ° C. g, preferably 1.2 dl / g <[η] <3.0 dl / g. When a random copolymer rubber (A) having an intrinsic viscosity [η] in the above range is used, a seal rubber part having excellent mechanical strength and low-temperature flexibility can be provided. A composition is obtained.

Further, the random copolymer (A) constituting the wiper blade rubber composition has an intrinsic viscosity [η] of 0.5 dl / g <[η] <5.0 dl / g measured in decalin at 135 ° C. , Preferably 0.8 dl / g <[η] <4.0 dl / g. When the random copolymer rubber (A) having the intrinsic viscosity [η] in the above range is used, a composition capable of providing a wiper blade rubber excellent in mechanical strength and low-temperature flexibility is obtained.

The random copolymer rubber (A) as described above is prepared by reacting ethylene, an α-olefin having 3 to 20 carbon atoms, and a branched polyene compound represented by the above general formula [I] in the presence of a catalyst. Can be obtained by copolymerization.

チ ー As such a catalyst, a Ziegler-type catalyst comprising a transition metal compound such as vanadium (V), zirconium (Zr), or titanium (Ti) and an organic aluminum compound (organic aluminum oxy compound) can be used.

In the present invention, [a] a catalyst comprising a soluble vanadium compound and an organoaluminum compound, or [b] a metallocene compound of a transition metal selected from Group IVB of the periodic table, and an organoaluminum oxy compound or an ionized ionic compound. Is particularly preferably used.

In the present invention, the above-mentioned catalyst [a] (a catalyst comprising a soluble vanadium compound and an organoaluminum compound) or catalyst [b] (a metallocene compound of a transition metal selected from Group IV of the periodic table and an organoaluminum oxy compound) Or, in the presence of a catalyst comprising an ionized ionic compound), ethylene, an α-olefin having 3 to 20 carbon atoms, and a branched polyene compound are usually copolymerized in a liquid phase.

At this time, a hydrocarbon solvent is generally used, but an α-olefin such as propylene may be used as the solvent.

As such a hydrocarbon solvent, specifically,
Aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane and kerosene and their halogen derivatives,
Alicyclic hydrocarbons such as cyclohexane, methylcyclopentane and methylcyclohexane, and halogen derivatives thereof,
Aromatic hydrocarbons such as benzene, toluene and xylene, and halogen derivatives such as chlorobenzene are used.

These solvents may be used in combination.
The copolymerization of ethylene, an α-olefin having 3 to 20 carbon atoms and a branched polyene compound may be performed by a batch method or a continuous method. When carrying out the copolymerization by a continuous method, the above-mentioned catalyst is used in the following concentration.

In the present invention, when the catalyst [a], that is, a catalyst comprising a soluble vanadium compound and an organoaluminum compound is used,
The concentration of the soluble vanadium compound in the polymerization system is usually 0.01 to 5 mmol / liter (polymerization volume), and preferably 0.05 to 3 mmol / liter. This soluble vanadium compound is desirably supplied at a concentration of 10 times or less, preferably 1 to 7 times, more preferably 1 to 5 times the concentration of the soluble vanadium compound present in the polymerization system.

The organoaluminum compound is supplied in an amount of 2 or more, preferably 2 to 50, and more preferably 3 to 20 in a ratio of aluminum atoms to vanadium atoms (Al / V) in the polymerization system.

The catalyst [a] composed of a soluble vanadium compound and an organoaluminum compound is usually supplied after being diluted with the above-mentioned hydrocarbon solvent and / or a liquid α-olefin having 3 to 20 carbon atoms and a branched polyene compound. You. At this time, the soluble vanadium compound is desirably diluted to the above-described concentration, and the organoaluminum compound is supplied to the polymerization system after being adjusted to an arbitrary concentration of, for example, 50 times or less the concentration in the polymerization system. desirable.

In the present invention, when a catalyst [b] composed of a metallocene compound and an organic aluminum oxy compound or an ionized ionic compound (also referred to as an ionic ionized compound or ionic compound) is used,
The concentration of the metallocene compound in the polymerization system is usually from 0.00005 to 0.1 mmol / liter (polymerization volume), preferably from 0.0001 to 0.05 mmol / liter.

The organic aluminum oxy compound is supplied in an amount of 1 to 10000, preferably 10 to 5000 in terms of the ratio of aluminum atoms to the metallocene compound in the polymerization system (Al / transition metal).

In the case of an ionized ionic compound, it is supplied in an amount of 0.5 to 20, preferably 1 to 10, in a molar ratio of the ionized ionic compound to the metallocene compound in the polymerization system (ionized ionic compound / metallocene compound). .

When an organoaluminum compound is used, it is generally used in an amount of about 0 to 5 mmol / l (polymerization degree), preferably about 0 to 2 mmol / l.

In the present invention, when ethylene, an α-olefin having 3 to 20 carbon atoms and a branched polyene compound are copolymerized in the presence of a catalyst [a] comprising a soluble vanadium compound and an organoaluminum compound, the copolymerization reaction, a temperature of usually -50 ° C. to 100 ° C., preferably from -30 ° C. to 80 ° C., further preferably -20 ° C. to 60 ° C., the pressure is 50 kg / cm ² or less, preferably 20 kg / cm ² It is performed under the following conditions. However, the pressure is not zero.

In the present invention, ethylene, an α-olefin having 3 to 20 carbon atoms and a branched polyene compound are copolymerized in the presence of a catalyst [b] comprising a metallocene compound and an organic aluminum oxy compound or an ionized ionic compound. When polymerizing, the copolymerization reaction is usually carried out at a temperature of -20 ° C to 150 ° C, preferably 0 ° C to 120 ° C, more preferably 0 ° C to 100 ° C, and a pressure of 80 kg / cm ² or less, preferably It is performed under the condition of 50 kg / cm ² or less. However, the pressure is not zero.

The reaction time (average residence time when the copolymerization is carried out by a continuous method) varies depending on conditions such as the catalyst concentration and the polymerization temperature, but is usually 5 minutes to 5 hours, preferably 10 minutes to 3 hours. It is.

In the present invention, ethylene, the α-olefin having 3 to 20 carbon atoms, and the branched polyene compound are supplied to the polymerization system in such an amount that the above-mentioned random copolymer rubber having the specific composition can be obtained. Further, at the time of copolymerization, a molecular weight regulator such as hydrogen can be used.

(4) When ethylene, an α-olefin having 3 to 20 carbon atoms and a branched polyene compound are copolymerized as described above, a random copolymer rubber is usually obtained as a polymerization solution containing the rubber. This polymerization liquid is treated by a conventional method to obtain a random copolymer rubber.

The method for preparing the random copolymer rubber (A) [unsaturated ethylenic copolymer] as described above is described in detail in the specification of Japanese Patent Application No. 7-69986 filed by the present applicant. .
Vulcanizing agent (B)
Examples of the vulcanizing agent (B) used in the present invention include sulfur, sulfur compounds, and organic peroxides.

Specific examples of the sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur.

Specific examples of the sulfur compound include sulfur chloride, sulfur dichloride, polymer polysulfide and the like. Sulfur compounds which release active sulfur at the vulcanization temperature and vulcanize such as morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide and the like can also be used.

In the present invention, the sulfur or the sulfur compound is used in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the random copolymer rubber (A).

When sulfur or a sulfur compound is used as the vulcanizing agent (B), it is preferable to use a vulcanization accelerator in combination. As the vulcanization accelerator, specifically,
N-cyclohexyl-2-benzothiazolesulfenamide, N-oxydiethylene-2-benzothiazolesulfenamide, N, N-diisopropyl-2-benzothiazolesulfenamide, 2-mercaptobenzothiazole, 2- (2, Thiazole compounds such as 4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole, dibenzothiazyldisulfide;
Guanidine compounds such as diphenylguanidine, triphenylguanidine, diorsonitrile guanidine, orthonitrile biguanide, diphenylguanidine phthalate;
Aldehyde amine or aldehyde-ammonia compounds such as acetaldehyde-aniline reactant, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde ammonia;
Imidazoline compounds such as 2-mercaptoimidazoline;
Thiourea-based compounds such as thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, and diorthotolylthiourea;
Thiuram compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide;
Dithioacid salts such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate and tellurium dimethyldithiocarbamate Compound;
Xanthate compounds such as zinc dibutylxanthate;
Compounds such as zinc white can be mentioned.

In the present invention, the vulcanization accelerator is used in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the random copolymer rubber (A).

The organic peroxide may be any compound that is generally used for peroxide vulcanization of rubber. For example, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl peroxide, benzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxin) hexyne-3, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5- Mono (t-butylperoxy) -hexane, α, α′-bis (t-butylperoxy-m-isopropyl) benzene and the like can be mentioned. Among them, dicumyl peroxide,
Di-t-butyl peroxide and di-t-butylperoxy-3,3,5-trimethylcyclohexane are preferably used. These organic peroxides are used alone or in combination of two or more.

In the present invention, the organic peroxide is used in a proportion of 3 × 10 ^{−4 to} 5 × 10 ⁻² mol per 100 parts by weight of the random copolymer rubber (A). It is desirable to appropriately determine the optimum amount according to the value.

When using an organic peroxide as the vulcanizing agent (B), it is preferable to use a vulcanizing aid in combination. Specific examples of the vulcanization aid include sulfur; quinone dioxime compounds such as p-quinone dioxime; methacrylate compounds such as polyethylene glycol dimethacrylate; allyl compounds such as diallyl phthalate and triallyl cyanurate; Other maleimide compounds; divinylbenzene and the like.

In the present invention, it is preferable to use an organic peroxide as the vulcanizing agent (B). When an organic peroxide is used as the vulcanizing agent (B), a seal rubber part and a wiper blade rubber having more excellent low-temperature flexibility can be obtained than using sulfur or a sulfur compound.
Filler (C)
The filler (C) used in the present invention includes a filler having a reinforcing property and a filler having no reinforcing property.

Reinforcing fillers have the effect of increasing the mechanical properties of vulcanized rubber, such as tensile strength, tear strength, and abrasion resistance. Specific examples of such a filler include carbon black, silica, activated calcium carbonate, and fine talc, which may be subjected to a surface treatment with a silane coupling agent or the like. In the present invention, any type of carbon black that is commonly used for rubber can be used regardless of its type.

充填 Fillers having no reinforcing properties are used for the purpose of increasing the hardness of rubber products and reducing costs without significantly affecting physical properties. Specific examples of such a filler include talc, clay, and calcium carbonate.

In the present invention, the filler (C) is used in an amount of 20 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the random copolymer rubber (A).
Other components In addition to the above random copolymer rubber (A), vulcanizing agent (B) and filler (C), in the composition for seal rubber parts or the composition for wiper blade rubber used in the present invention, As described above, a vulcanization accelerator and a vulcanization aid can be blended, but in addition, an antioxidant, a processing aid, a heat stabilizer, a weather stabilizer, an antioxidant, an antistatic agent, a coloring agent, Lubricants, plasticizers, and other rubber compounding agents can be compounded within a range that does not impair the purpose of the present invention.

Specific examples of the antioxidant include poly (2,2,4-trimethyl-1,2-dihydroquinoline, N, N′-di-2-naphthyl-p-phenylenediamine, 2,6-di- t-butyl-4-methylphenol, 4,4′-thio-bis (6-t-butyl-3-methylphenol), 2-mercaptobenzimidazole, nickel dibutyl-dithiocarbamate and the like.

As the processing aid, a processing aid usually used for rubber is used. Examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, calcium stearate, zinc stearate, esters of the above acids, higher fatty acids and salts and esters thereof.
Preparation of Composition The composition for seal rubber parts and the composition for wiper blade rubber used in the present invention can be prepared, for example, by the following method.

That is, the composition for the seal rubber part and the composition for the wiper blade rubber used in the present invention are obtained by mixing a random copolymer rubber (A), a filler (C), a plasticizer and the like with a mixer such as a Banbury mixer. After kneading the additive at a temperature of 80 to 170 ° C. for about 3 to 10 minutes, a vulcanizing agent (B), if necessary, an antioxidant, a vulcanization accelerator, using rolls such as an open roll. It can be prepared by additionally mixing an agent or a vulcanization aid, kneading at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, and then dispensing. The rubber composition thus obtained is a ribbon-shaped or sheet-shaped rubber compound.

Further, the composition for seal rubber parts and the composition for wiper blade rubber used in the present invention are composed of a random copolymer rubber (A), a vulcanizing agent (B), a filler (C) and the above-mentioned additives in an amount of about 80%. It can also be fed directly to an extruder heated to １００100 ° C., set to a residence time of about 0.5 to 5 minutes, granulated, and prepared into pellets.
Seal rubber part The seal rubber part according to the present invention is formed of the composition for a seal rubber part as described above, and the rubber is usually vulcanized.

The seal rubber part according to the present invention can be prepared by a conventionally known method for preparing a seal rubber part.
Wiper Blade Rubber The wiper blade rubber according to the present invention is formed of the above-described composition for wiper blade rubber, and is usually vulcanized.

ワ イ The wiper blade rubber according to the present invention can be prepared by a conventionally known preparation method.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

The evaluation test methods for the ethylene / α-olefin / polyene copolymer rubber and the vulcanized rubber in Examples and Comparative Examples are as follows.

[1] Physical property test of unvulcanized rubber The physical property test of the unvulcanized rubber is performed in accordance with JIS K 6300, and the unvulcanized rubber is a CURELAST METER 3 manufactured by Nippon Synthetic Rubber Co., Ltd. The change in torque was measured at 160 ° C. using a mold, t ₉₀ [min] was determined, and the result was taken as the vulcanization rate. t ₉₀ indicates that the faster the vulcanization rate a short period of time.

[2] Tensile test A vulcanized rubber sheet was punched out to prepare a No. 3 type dumbbell test piece described in JIS K 6301 (1989), and the test piece was used and specified in JIS K 6301 Paragraph 3. according to the method, measurement temperature 25 ° C., subjected to tensile test at a tensile rate of 500 mm / min condition, the tensile stress at break T _B and tensile elongation at break E _B were measured.

[3] Hardness test The hardness test is performed according to JIS K 6301 (1989), and the spring hardness H _S (JI
S A hardness) was measured.

[4] Compression set test The compression set test is performed in accordance with JIS K 6301 (1989). For the vulcanized rubber of the composition for sealing rubber parts, the high temperature compression set (CS) is determined, and the wiper blade is used. The low temperature compression set (CS) of the vulcanized rubber of the rubber composition was determined. The lower the low-temperature compression set, the better the low-temperature flexibility.

Test conditions for composition for sealing rubber parts Heating temperature: 150 ° C
Time: 22 hours Load: 10.5kg
Test conditions for composition for wiper blade rubber Cooling temperature: -22 ° C
Time: 22 hours Load: 10.5kg
[5] Low temperature torsion test (Gaeman torsion test)
The low-temperature torsion test was performed according to JIS K6301, and T ₂ [° C.] and freezing temperature [° C.] were determined. These temperatures are indicators of the low temperature flexibility of the vulcanized rubber. More T ₂ is low, the low temperature flexibility is good.

(Test condition)
Torsion constant of twisted wire: 0.5 gf · cm / degree Immersion time: 10 minutes Twisting time: 5 seconds The random copolymer rubbers used in Examples and Comparative Examples are as shown in Table 1.

[Examples and Comparative Examples of Seal Rubber Parts]

100 parts by weight of the copolymer (1), 5 parts by weight of zinc white, 1 part by weight of stearic acid, and 50 parts by weight of MAF carbon black [filler, manufactured by Tokai Carbon Co., Ltd., Seast 116] were added in a capacity of 1 The mixture was kneaded for 6 minutes with a 0.7 liter Banbury mixer [manufactured by Kobe Steel Ltd.].

To the kneaded material thus obtained, 3 parts by weight of dicumyl peroxide [manufactured by NOF CORPORATION] and 0.1 parts by weight of sulfur [vulcanization aid] were added, and an 8-inch roll having a roll width of 20 inches was added. After kneading for 15 minutes at a temperature of 40 ° C. of the front roll and the rear roll, the mixture was separated into sheets, and 170 ° C. for 10 minutes (for compression set measurement, 170 ° C. for 20 minutes) at 150 kg / cm ² . To vulcanize a sheet having a thickness of 2 mm.

に つ い て The obtained vulcanized sheet was subjected to the above-mentioned physical properties test and the like according to the above-mentioned method.

Further, the unvulcanized rubber composition before performing the vulcanization, according to the method described above, was determined t _90.

The results are shown in Table 2.

[Examples 2, 3, and 4]
Example 1 was repeated except that the copolymers (2), (3) and (4) shown in Table 1 were used instead of the copolymer (1).

The results are shown in Table 2.

[Comparative Examples 1 and 2]
Example 1 was repeated except that the copolymers (8) and (9) shown in Table 1 were used instead of the copolymer (1).

The results are shown in Table 2.

[Examples and Comparative Examples of Wiper Blade Rubber]
[Example 5]
100 parts by weight of the copolymer (5) shown in Table 1, 5 parts by weight of zinc white, 1 part by weight of stearic acid, 70 parts by weight of FEF carbon black, and 30 parts by weight of dioctyl sebacate [plasticizer] Was kneaded with a 4.3 liter Banbury mixer [manufactured by Kobe Steel Ltd.] for 5 minutes.

To the kneaded product thus obtained, 7.0 parts by weight of dicumyl peroxide (content: 40%) and 1.5 parts by weight of trimethylolpropane trimethacrylate were added, and an 8-inch mixing roll (the front roll and the rear roll) was added. After kneading at a temperature of 50 ° C.), the mixture was separated into sheets and press-vulcanized at 170 ° C. for 12 minutes to prepare a vulcanized sheet having a thickness of 2 mm.

に つ い て The obtained vulcanized sheet was subjected to the above-mentioned physical properties test and the like according to the above-mentioned method.

Further, the unvulcanized rubber composition before performing the vulcanization, according to the method described above, was determined t _90.

The results are shown in Table 3.

[Examples 6 and 7]
Example 5 was carried out in the same manner as in Example 5, except that the copolymers (6) and (7) shown in Table 1 were used instead of the copolymer (5).

The results are shown in Table 3.

[Comparative Examples 3 and 4]
Example 5 was carried out in the same manner as in Example 5, except that the copolymers (10) and (11) shown in Table 1 were used instead of the copolymer (5).

The results are shown in Table 3.

Claims (1)

A random copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and at least one kind of branched polyene compound represented by the following general formula [I];
Vulcanizing agent (B) and filler (C)
Formed of a rubber composition containing
The random copolymer rubber (A)
(I) the molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) is in the range of 55/45 to 75/25;
(Ii) the iodine value is in the range of 5 to 30,
(Iii) a wiper blade rubber, wherein the intrinsic viscosity [η] measured in decalin at 135 ° C. is in a range represented by 0.5 dl / g <[η] <5.0 dl / g;

[In the formula [I], n is an integer of 1 to 5,
R ¹ is an alkyl group having 1 to 5 carbon atoms,
R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms].