JP2001131531A - Sealing rubber part and wiper blade rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing rubber part excellent in heat aging resistance and flexibility at a low temperature and a wiper blade rubber excellent in rubber elasticity and flexibility at a low temperature. SOLUTION: The sealing rubber part and wiper blade rubber are formed with (A) a random copolymer rubber consisting of structural units derived from ethylene, a 3-20C α-olefin and a specific triene compound, (B) a vulcanizing agent and (C) a filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 excellent in low-temperature flexibility.

[0002]

BACKGROUND OF THE INVENTION Ethylene / propylene / non-conjugated diene copolymer rubber (hereinafter sometimes referred to as EPT)
Because of its excellent heat aging resistance, weather resistance, water resistance, chemical resistance, low temperature properties and flexibility, it can be used for packing household jars, sealing materials at the junction between glass and sashes, and automotive window frames. In recent years, it has been known to be used as a hydraulic cylinder sealing material for automobiles, such as a cup for a brake master cylinder and a cup for a brake wheel cylinder in a hydraulic brake, in addition to the use of sealing rubber parts such as a sealing material.

Hitherto, 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 increased, the temperature inside the engine room has increased,
Butadiene rubber is thermally degraded and is no longer a preferred seal. Therefore, EPT has recently become the mainstream in place of styrene-butadiene rubber.

A composition for sealing rubber parts disclosed in Japanese Patent Application Laid-Open No. 1-268743 is also one example of the composition, in which (a) the ethylene content is 58-72 mol%, and (b) the maximum tensile strength. The product of stress (RS [kgf / cm ² ] and elongation at break (ε [%]) is 1 × 10 3 to 20 × 10
3 and (c) Mooney viscosity [ML (1 + 4) 100
C.] is 20 to 50, and (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. .

[0005] However, although the seal rubber component disclosed in this publication has good low-temperature flexibility, it does not yet have satisfactory low-temperature flexibility, and there is still room for improvement.

[0006] On the other hand, EPT is used for automobile parts by taking advantage of its excellent weather resistance. Among such automotive parts applications, the wiper blade rubber is required to exhibit good flexibility in a wide temperature range, particularly at a low temperature. 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 EPT, hinders the movement of molecular chains due to its structure. There is a problem that the flexibility at low temperatures is adversely affected. Further, when the ENB content is reduced to improve the low-temperature flexibility, there is a problem that the vulcanization rate becomes slow and the productivity becomes low.

Accordingly, a seal rubber part having significantly improved low-temperature flexibility without impairing the inherent excellent heat aging resistance and weather resistance of EPT, and a wiper blade rubber excellent in low-temperature flexibility and rubber elasticity. The appearance has long been desired.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, and to reduce the low temperature without deteriorating the excellent heat aging and weather resistance inherent of EPT. It is an object of the present invention to provide a seal rubber part having significantly improved flexibility.

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

[0011]

SUMMARY OF THE INVENTION A seal rubber part according to the present invention is a random copolymer comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a structural unit derived from a triene compound represented by the following general formula [1]. The random copolymer rubber (A) is formed of a rubber composition containing a coalesced rubber (A), a vulcanizing agent (B), and a filler (C).
The molar ratio of ethylene to α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) is 99/1 to 30 /
70, (ii) the content of the structural unit derived from the triene compound is 0.1 to 30 mol%, and (ii)
i) The intrinsic viscosity [η] measured in decalin at 135 ° C. is in the range of 0.1 to 10 dl / g.

[0012]

Embedded image [In the formula [1], R ¹ and R ² are each independently a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ are each independently a methyl group or an ethyl group. ]

The wiper blade rubber according to the present invention is a random copolymer comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a structural unit derived from a triene compound represented by the following general formula [1]. The random copolymer rubber (A) is formed of a rubber composition containing a rubber (A), a vulcanizing agent (B), and a filler (C).
(I) The molar ratio of ethylene to α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) is 99/1 to
(Ii) the content of the structural unit derived from the triene compound is 0.1 to 30 mol%, and (iii) the intrinsic viscosity [η] measured at 135 ° C. in decalin is 0. 0.1 to 10 dl / g.

[0014]

Embedded image

[In the formula [1], R ¹ and R ² are each independently a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ are each independently a methyl group or an ethyl group. ]

[0016]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the seal rubber component and the wiper blade rubber according to the present invention will be specifically described.

[0017] The seal rubber component and the wiper blade rubber according to the present invention have a specific random copolymer rubber (A).
And 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 the 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,
Examples thereof include 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. 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. The structural unit derived from the triene compound has the following general formula [1]
Is represented by

[0021]

Embedded image

[In the formula [1], R ¹ and R ² are each independently a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ are each independently a methyl group or an ethyl group. ]

Among the triene compounds represented by the above formula [1], a compound in which R ³ and R ⁴ are both methyl groups is preferred. A random copolymer rubber obtained by using such a triene compound as a monomer material is It is particularly excellent in the balance between vulcanization rate and scorch characteristics.

Specific examples of the triene compound represented by the above formula [1] include the following compounds.

Embedded image These triene compounds are disclosed in Japanese Patent Application No. 11-146429.
It can be manufactured by the method described in (1).

Among the above triene compounds, 4,8-dimethyl-1,4,8-decatriene (hereinafter abbreviated as DMDT), which is the first exemplified, is preferable. The triene compound represented by the formula [1] may be a mixture of a trans form and a cis form, or may be a trans form alone or a cis form alone.

The triene compound represented by the formula [1] is obtained by reacting a compound having a conjugated diene represented by the following formula [2] with ethylene in the presence of a catalyst comprising a transition metal compound and an organoaluminum compound. Can be manufactured.

[0027]

Embedded image

[0028] (wherein ^{[2], R 1, R} 2, R 1 in R ³ and R ⁴ in general formula described above, respectively ^{[1], R 2, R} 3
And R ⁴ are the same. In the random copolymer rubber (A) used in the present invention, the structural units derived from the monomers of the ethylene, α-olefin and triene compounds as described above are randomly arranged and bonded to form a triene rubber. It has a branched structure due to the compound, and the main chain has a substantially linear structure.

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 the insoluble content is substantially reduced. It can be confirmed by not including it. For example, when the intrinsic viscosity [η] is measured, it can be confirmed that the copolymer rubber is completely dissolved in decalin at 135 ° C.

In such a random copolymer rubber (A), the structural unit derived from the triene compound has a structure substantially represented by the following formula [3].

[0031]

Embedded image

[0032] (wherein ^{[3], R 1, R} 2, R 1 in R ³ and R ⁴ in general formula described above, respectively ^{[1], R 2, R} 3
And R ⁴ are the same. The fact that the structural unit derived from the triene compound has the above structure can be confirmed by measuring the ¹³ C-NMR spectrum of the copolymer.

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 is composed of ethylene and α having 3 to 20 carbon atoms.
-Molar ratio with olefin (ethylene / α-olefin)
Is 50/50 to 75/25, preferably 55/45 to 7
It is in the range of 3/27.

The use of the random copolymer rubber (A) in which the molar ratio of ethylene to the α-olefin having 3 to 20 carbon atoms is in the above-mentioned range provides excellent mechanical strength and low-temperature flexibility. The composition which can provide the sealing rubber component excellent in the above can be obtained.

The random copolymer rubber (A) constituting the wiper blade rubber composition has a molar ratio of ethylene to α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) of 55 /. It is in the range of 45-75 / 25, preferably 60 / 40-73 / 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, a wiper blade rubber having excellent low-temperature flexibility can be obtained. Can be provided,
A composition having excellent crosslinking efficiency with an organic peroxide can be obtained.

(Ii) The content of the triene compound in the random copolymer rubber (A) constituting the composition for sealing rubber parts is 0.1 to 30 mol%, preferably 0.3 to 8 mol%, particularly preferably 0 to 8 mol%. In the range of 0.5 to 5 mol%. When a random copolymer rubber (A) having a triene compound content in the above range is used, excellent low-temperature flexibility is obtained,
A composition having a high vulcanization rate that can provide a sealing rubber part having a small compression set and a small tensile elongation is obtained.

The content of the triene compound in the random copolymer rubber (A) constituting the wiper blade rubber composition is 0.1 to 30 mol%, preferably 0.3 to 8 mol%, and particularly preferably 0 to 8 mol%. In the range of 0.5 to 5 mol%. When a random copolymer rubber (A) having a triene compound content 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.

EPT in which the third component is 4,8-dimethyl-1,4,8-decatriene (hereinafter sometimes abbreviated as DMDT) (hereinafter sometimes abbreviated as DMDT-EPT)
And the third component is 5-ethylidene-2-norbornene (hereinafter, referred to as
EPT (hereinafter sometimes referred to as ENB)
Compared with B-EPT (sometimes abbreviated as B-EPT) at the same iodine value, DMDT-EPT has a vulcanization rate more than twice as fast.

The third component is 4-ethylidene-8-methyl
-1,7- Nonadiene (EMND) EPT is also DM
It shows the same vulcanization rate as DT-EPT, but DMDT-EP
T has a longer t ₅ than EMND-EPT, and has higher scorch stability.

It should be noted that ENB-EPT has a polyene content of more than 4 mol% even if its polyene content is increased.
The effect of improving the vulcanization rate is lost. On the other hand, DMDT-EP
T can increase the vulcanization rate in proportion to the polyene content until its polyene content is 7 mol%.

Further, when the iodine value of ENB-EPT is increased in order to increase the vulcanization rate, the low-temperature flexibility deteriorates proportionately. On the other hand, DMDT-EPT has excellent low-temperature flexibility regardless of its iodine value.

(Iii) The random copolymer rubber (A) constituting the composition for sealing rubber parts has an intrinsic viscosity [η] of 1.2 dl / g <[η] <measured in decalin at 135 ° C.
3.5 dl / g, preferably 1.2 dl / g <[η] <3.
It is in the range represented by 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, and excellent roll processability can be obtained. A composition is obtained.

The random copolymer (A) constituting the wiper blade rubber composition has an intrinsic viscosity [η] measured in decalin at 135 ° C. of 0.5 dl / g <[η] <
5.0 dl / g, preferably 0.8 dl / g <[η] <4.
It is in the range represented by 0 dl / g. When a random copolymer rubber (A) having an 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 above random copolymer rubber (A)
Can be obtained by copolymerizing ethylene, an α-olefin having 3 to 20 carbon atoms, and a structural unit derived from the triene compound represented by the general formula [1] in the presence of a catalyst.

As such a catalyst, a Ziegler 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 A catalyst comprising a compound is particularly preferably used.

In the present invention, the catalyst [a] (a catalyst comprising a soluble vanadium compound and an organoaluminum compound) or the catalyst [b] (a metallocene compound of a transition metal selected from Group IV of the periodic table) and an organic Ethylene in the presence of an aluminum oxy compound or a catalyst comprising an ionized ionic compound) and ethylene having an α of 3 to 20 carbon atoms.
-An olefin and a structural unit derived from a triene compound are usually copolymerized in a liquid phase.

In this case, a hydrocarbon solvent is generally used, but an α-olefin such as propylene may be used as the solvent. Specific examples of such hydrocarbon solvents include pentane, hexane, heptane, octane, decane, dodecane, aliphatic hydrocarbons such as kerosene and halogen derivatives thereof, cyclohexane, methylcyclopentane,
Alicyclic hydrocarbons such as 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 structural unit derived from a triene compound may be carried out by either a batch method or a continuous method. When the copolymerization is carried out by a continuous method, the above-mentioned catalyst is used in the following concentration.

In the present invention, when the above-mentioned 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 from 0.01 to 5%. Mmol / liter (polymerization volume), 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 has a ratio of aluminum atoms to vanadium atoms in the polymerization system (A
1 / V), and is supplied in an amount of 2 or more, preferably 2 to 50, more preferably 3 to 20.

The catalyst [a] comprising a soluble vanadium compound and an organoaluminum compound is usually diluted with the above-mentioned hydrocarbon solvent and / or a liquid α-olefin having 3 to 20 carbon atoms and a branched polyene compound. Supplied. At this time, the soluble vanadium compound is desirably diluted to the concentration described above, and the organoaluminum compound is diluted to, for example, 50% of the concentration in the polymerization system.
It is desirable to adjust the concentration to an arbitrary concentration of 2 times or less and supply it to the polymerization system.

In the present invention, when a catalyst [b] comprising 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, a polymerization system The concentration of the metallocene compound in is usually 0.1.
0.0005-0.1 mmol / liter (polymerization volume),
Preferably it is 0.0001-0.05 mmol / l.

The organic aluminum oxy compound is
It is supplied in an amount of 1 to 10,000, preferably 10 to 5,000 in terms of the ratio of aluminum atoms to the metallocene compound in the polymerization system (Al / transition metal).

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

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, ethylene, an α-olefin having 3 to 20 carbon atoms and a structural unit derived from a triene compound are copolymerized in the presence of a catalyst [a] comprising a soluble vanadium compound and an organoaluminum compound. When it is carried out, the copolymerization reaction is usually carried out at a temperature of -50C to 10C.
The reaction is carried out at 0 ° C., preferably at −30 ° C. to 80 ° C., more preferably at −20 ° C. to 60 ° C., and at a pressure of 5 MPa or less, preferably 2 MPa or less. However, the pressure is 0
is not.

In the present invention, ethylene, an α-olefin having 3 to 20 carbon atoms and a triene compound are derived in the presence of a catalyst [b] comprising a metallocene compound and an organic aluminum oxy compound or an ionized ionic compound. When copolymerizing with a structural unit, the temperature of the copolymerization reaction is usually from -20 ° C to 150 ° C, preferably 0 ° C.
C. to 120.degree. C., more preferably 0.degree. C. to 100.degree. C., under a pressure of 8 MPa, preferably 5 MPa or less. However, the pressure is not zero.

The reaction time (average residence time when 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. ~ 3 hours.

In the present invention, ethylene, C 3 -C 2
The structural unit derived from the α-olefin and the triene compound of 0 is supplied to the polymerization system in such an amount as to obtain the random copolymer rubber having the above specific composition. Further, upon copolymerization, a molecular weight regulator such as hydrogen may be used.

As described above, ethylene and carbon atom 3
When structural units derived from α-olefins and triene compounds of from 20 to 20 are copolymerized, a random copolymer rubber is usually obtained as a polymerization liquid containing the same. This polymerization liquid is
It is processed 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 Japanese Patent Application No. 7-69986.

Vulcanizing Agent (B) Examples of the vulcanizing agent (B) used in the present invention include sulfur, sulfur compounds, and organic peroxides.

Examples of the sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur. As sulfur compounds,
Specific examples include sulfur chloride, sulfur dichloride, polymer polysulfide, and the like. Sulfur compounds that 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). Can be

When sulfur or a sulfur compound is used as the vulcanizing agent (B), it is preferable to use a vulcanization accelerator in combination. Specific examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazolesulfenamide,
N-oxydiethylene-2-benzothiazolesulfenamide, N, N-diisopropyl-2-benzothiazolesulfenamide, 2-mercaptobenzothiazole, 2- (2,4-
Dinitrophenyl) mercaptobenzothiazole, 2-
(2,6-Diethyl-4-morpholinothio) thiazole compounds such as benzothiazole and dibenzothiazyldisulfide; guanidine compounds such as diphenylguanidine, triphenylguanidine, diorsonitrileguanidine, orthonitrile biguanide, diphenylguanidine phthalate Acetaldehyde-aniline reactants, butyraldehyde-aniline condensates, aldehyde amines such as hexamethylenetetramine, acetaldehyde ammonia or aldehyde-ammonia compounds; imidazoline compounds such as 2-mercaptoimidazoline; thiocarbanilide, diethylthiourea, dibutylthiourea ,
Thiourea compounds such as trimethylthiourea and diortho tolyl thiourea; thiuram compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide; zinc dimethyldithiocarbamate ,
Dithioxanthogen compounds such as zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate and tellurium dimethyldithiocarbamate; dibutylxanthogen Xanthate compounds such as zinc acid; and compounds such as zinc white.

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

The organic peroxide may be any compound which is usually 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-butyl Peroxin) 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,
Di-t-butylperoxy-3,3,5-trimethylcyclohexane is preferably used. These organic peroxides
One type or a combination of two or more types is used.

In the present invention, the organic peroxide is 3 × 1 based on 100 parts by weight of the random copolymer rubber (A).
It is used in a proportion of 0 ^{-4 to} 5 × 10 ^-2 mol, but it is desirable to determine an optimum amount appropriately according to the required physical properties.

When an organic peroxide is used 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 include divinylbenzene.

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.

The reinforcing filler has an effect of improving mechanical properties such as tensile strength, tear strength and abrasion resistance of the vulcanized rubber. As such a filler, specifically,
Examples thereof include carbon black, silica, activated calcium carbonate, and fine talc, which may be subjected to a surface treatment with a silane coupling agent. In the present invention, any type of carbon black that is commonly used for rubber can be used regardless of its type.

Further, the filler having no reinforcing property can increase the hardness of the rubber product without significantly affecting the physical properties,
Used to reduce costs. As such a filler, specifically, talc, clay,
Calcium carbonate and the like.

In the present invention, the filler (C) is used in an amount of 20 to 100 parts by weight of the random copolymer rubber (A).
It is used in a proportion of 200 parts by weight, preferably 50 to 150 parts by weight.

Other Components In the composition for seal rubber parts or the composition for wiper blade rubber used in the present invention, the above random copolymer rubber (A), vulcanizing agent (B) and filler (C) are added. In addition, vulcanization accelerators and vulcanization aids can be blended as described above, but in addition to these, antioxidants, processing aids, heat stabilizers, weather resistance stabilizers, antioxidants, antistatic agents, Coloring agents, lubricants, plasticizers and other rubber compounding agents can be compounded within a range that does not impair the purpose of the present invention.

As the antioxidant, specifically, 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-mercaptobenzo Imidazole, nickel dibutyl-dithiocarbamate and the like.

As processing aids, processing aids usually used for rubber are used. Examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, calcium stearate, zinc stearate, and other 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 a seal rubber part and the composition for a wiper blade rubber used in the present invention are:
Necessary additives such as a random copolymer rubber (A), a filler (C), and a plasticizer are kneaded by a mixer such as a Banbury mixer at a temperature of 80 to 170 ° C. for about 3 to 10 minutes, and then opened. Using a roll such as a roll, a vulcanizing agent (B) and, if necessary, an antioxidant, a vulcanization accelerator or a vulcanization aid are additionally mixed, and a roll temperature of 40 to 80
It can be prepared by kneading at 5 ° C. for 5 to 30 minutes and then dispensing. The rubber composition thus obtained is a ribbon-shaped or sheet-shaped rubber compound.

The composition for a seal rubber part and the composition for a wiper blade rubber used in the present invention comprise a random copolymer rubber (A), a vulcanizing agent (B), and a filler (C).
Alternatively, the above additives can be directly supplied to an extruder heated to about 80 to 100 ° C., and 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 above-described composition for a seal rubber part, 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.

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

[0086]

According to the present invention, the random copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a structural unit derived from the above-mentioned triene compound is ethylene, α-olefin. Since the molar ratio, iodine value and intrinsic viscosity [η] are within specific ranges, 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) has excellent properties such as weather resistance, ozone resistance and heat aging resistance.

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

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

The wiper blade rubber according to the present invention comprises the above random copolymer rubber (A) and a vulcanizing agent (B)
And a filler (C), so that the composition is excellent in low-temperature flexibility.

The wiper blade rubber having excellent low-temperature flexibility according to the present invention has an excellent wiper effect even in a cold environment of 0 ° C. or less. 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 / triene 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 was performed in accordance with JIS K 6300. The scorch stability was measured using a Mooney viscometer (model SMV-202) manufactured by Shimadzu Corporation at 125 ° C. and the change in Mooney viscosity was measured at t ₅ [min].
As a guide. The t ₅ indicates the longer scorch that stability is good. The vulcanization rate, using a Monsanto rotor-less rheometer (model MDR 2000), to measure the change in torque at 160 ° C., t _c (9
0) was obtained and used as a guide. The shorter the t _c (90), the faster the vulcanization rate.

[2] Tensile test A vulcanized rubber sheet was punched out and JIS K6251 (199)
No. 3 dumbbell test piece described in (3 years), and using this test piece, a measurement temperature of 25 ° C. and a tensile speed of 50 were applied in accordance with the method specified in JIS K 6251, Paragraph 3.
A tensile test was carried out under the conditions of 0 mm / min, and 100% modulus (M100), 200% modulus (M200), 30%
0% modulus (M300), tensile stress at break T _B and tensile elongation at break E _B were measured.

[3] Hardness Test The hardness test was performed according to JIS K 6253 (1993), and the spring hardness H _A (Shore A hardness) was measured.

[4] Compression set test The compression set test was performed according to JIS K 6262 (1993).
The vulcanized rubber of the composition for seal rubber parts is determined for the high temperature compression set (C _S ), and the vulcanized rubber of the wiper blade rubber composition is determined for the low temperature compression set (C _S ). I asked. The lower the low-temperature compression set, the better the low-temperature flexibility.

[5] Low-temperature torsion test (Gehman torsion test) The low-temperature torsion test was performed according to JIS K 6261 (1993), and t ₂ [° C.] and freezing temperature [° C.] were determined.
These temperatures are indicators of the low temperature flexibility of the vulcanized rubber.
as t ₂ is low, the low temperature flexibility is good.

Table 1 shows the random copolymer rubber (EPT) used in the examples and comparative examples.

[0097]

[Table 1]

[Examples and Comparative Examples of Seal Rubber Parts]

[0099]

Example 1 The above-mentioned ethylene / propylene / 4,8-dimethyl-1,4,8-decatriene copolymer rubber (DMDT-EPT-1) 100 was used as the random copolymer rubber (A).
Parts by weight, 5 parts by weight of zinc white, 1 part by weight of stearic acid, and 50 parts by weight of MAF carbon black [filler, Seast 116 manufactured by Tokai Carbon Co., Ltd.]
The mixture was kneaded with a 7 liter Banbury mixer [manufactured by Kobe Steel Ltd.] for 6 minutes.

To the kneaded product thus obtained, 3 parts by weight of dicumyl peroxide (manufactured by NOF Corporation) and 0.1 part by weight of sulfur (vulcanization aid) were added, and a roll width of 20 was added.
After kneading for 15 minutes on an 8-inch roll (temperature of the front roll and the rear roll of 40 ° C.) for 15 minutes, the mixture is separated into sheets, and 170 ° C. for 10 minutes (for compression set measurement, 170 ° C. for 20 minutes), 150 kg Vulcanized sheet having a thickness of 2 mm was prepared by press vulcanization under the condition of / cm ² .

The obtained vulcanized sheet was subjected to the above-mentioned physical properties test and the like according to the above-mentioned method. Further, for the unvulcanized rubber composition before performing the above vulcanization, according to the above method,
t _c (90) and t ₅ were determined.

Table 2 shows the results.

[0103]

Embodiment 2 In Embodiment 1, DMDT-EPT-1
Was performed in the same manner as in Example 1 except that DMDT-EPT-2 shown in Table 1 was used instead of.

Table 2 shows the results.

[0105]

Comparative Examples 1 and 2 In Example 1, DMDT-EPT was used.
Example 1 was repeated except that ENB-EPT-1, 2 shown in Table 1 was used instead of -1.

Table 2 shows the results.

[0107]

[Table 2]

[Examples and Comparative Examples of Wiper Blade Rubber]

[0109]

Embodiment 3 Ethylene / propylene / 4,8 shown in Table 1
-Dimethyl-1,4,8-Decatriene copolymer rubber (D
MDT-EPT-3) 100 parts by weight, 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] in a capacity of 4.3 The mixture was kneaded with a liter Banbury mixer [manufactured by Kobe Steel Ltd.] for 5 minutes.

To the kneaded material thus obtained, 7.0 parts by weight of dicumyl peroxide (40% content) and 1.5 parts by weight of trimethylolpropane trimethacrylate were added, and an 8 inch mixing roll (front roll and After kneading at a rear roll 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.

The obtained vulcanized sheet was subjected to the above-mentioned physical property tests and the like according to the above-mentioned methods. Further, for the unvulcanized rubber composition before performing the above vulcanization, according to the above method,
t _c (90) and t ₅ were determined.

Table 3 shows the results.

[0113]

Fourth Embodiment In the third embodiment, DMDT-EPT-3 is used.
Was performed in the same manner as in Example 3 except that DMDT-EPT-4 shown in Table 1 was used instead of.

Table 3 shows the results.

[0115]

Comparative Examples 3 and 4 In Example 3, DMDT-EPT was used.
Example 3 was repeated except that ENB-EPT-3 and 4 shown in Table 1 were used instead of -3.

Table 3 shows the results.

[0117]

[Table 3]

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Claims (2)

[Claims] 1. A random copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms and a structural unit derived from a triene compound represented by the following general formula [1]: The random copolymer rubber (A) is formed of a rubber composition containing an agent (B) and a filler (C), and (i) ethylene and an α-olefin having 3 to 20 carbon atoms. Is in the range of 99/1 to 30/70, (ii) the content of the structural unit derived from the triene compound is 0.1 to 30 mol%, and (iii) ) 135 ° C
Intrinsic viscosity [η] measured in decalin is 0.1 to 10 d
a sealing rubber part characterized by being in the range of 1 / g; [In the formula [1], R ¹ and R ² are each independently a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ are each independently a methyl group or an ethyl group. ] 2. A random copolymer rubber (A) comprising ethylene, an α-olefin having 3 to 20 carbon atoms, and a structural unit derived from a triene compound represented by the following general formula [1]: The random copolymer rubber (A) is formed of a rubber composition containing an agent (B) and a filler (C), and (i) ethylene and an α-olefin having 3 to 20 carbon atoms. Is in the range of 99/1 to 30/70, (ii) the content of the structural unit derived from the triene compound is 0.1 to 30 mol%, and (iii) ) 135 ° C
Intrinsic viscosity [η] measured in decalin is 0.1 to 10 d
a wiper blade rubber characterized by being in the range of 1 / g; [In the formula [1], R ¹ and R ² are each independently a hydrogen atom, a methyl group or an ethyl group, and R ³ and R ⁴ are each independently a methyl group or an ethyl group. ]