JP2001151958A - Rubber composition for roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for rolls which is excellent in resistances to abrasion and heat aging and in compression set properties, has a hardness as low as 37 or lower, and is rapidly vulcanized. SOLUTION: This composition comprises (A) a random copolymer rubber comprising structural units derived from ethylene, a 3-20C α-olefin, and a triene compound represented by formula [1], (B) a vulcanizing agent, and (C) a filler. The random copolymer rubber has a molar ratio of ethylene to the 3-20C α- olefin of (99/1)-(30/70), a content of structural units derived from the triene compound of 0.1-30 mol%, and an intrinsic viscosity [η] (measured at 135 deg.C in decalin) of 0.1-10 dL/g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a roll, and more particularly, to a rubber composition for a roll having excellent abrasion resistance, heat aging resistance and compression set characteristics.

[0002]

BACKGROUND OF THE INVENTION Rubber rolls are manufactured by bonding and coating rubber onto a metal core. Rubber rolls generally have some or all of the following characteristics: high elasticity, wear resistance, oil resistance, heat resistance, chemical resistance, compression set, weather resistance, ozone resistance, wear resistance, etc. Is required.

[0003] Among the above properties, rubber rolls that require heat resistance, weather resistance, ozone resistance and abrasion resistance are conventionally used.
Ethylene / propylene / polyene copolymer rubber (hereinafter sometimes abbreviated as “EPT”) is used as a rubber component of the rubber molded product. However, EPT
Because inferior in wear resistance, also the change in hardness after heat aging (H _A) and strength and elongation (break strength T _B, elongation at break E _B), so-called thermal aging resistance is not necessarily sufficient, and Applications are also limited. Further, at present, it is difficult to produce a low-hardness rubber roll such as a paper feed rubber roll having a Shore A hardness of 30 in the conventional EPT.

[0004] As a method of improving the abrasion resistance of the EPT, it is conceivable to mix carbon black with the EPT. However, this method has a problem that the hardness of the rubber is increased and the workability is remarkably deteriorated.

As a method for improving the heat aging resistance of EPT, a method in which an antioxidant is added to EPT and vulcanization is performed by an organic peroxide vulcanization method or a low sulfur vulcanization method has conventionally been adopted. I have. However, such a method cannot be expected to improve the abrasion resistance of the EPT.

When EPT is used as the rubber for the low hardness rubber roll, a large amount of process oil must be blended with the EPT, and as a result, the shape retention of the blend when unvulcanized is deteriorated, and the Shore A hardness is reduced. It is the utmost to produce a rubber molded body for rolls having a hardness of about 37.

[0007] The compression set of the EPT vulcanizate is greatly affected by its vulcanization method. In general, when EPT is vulcanized by low sulfur vulcanization, sulfur-free vulcanization or organic peroxide vulcanization, The vulcanizates exhibit good compression set properties. However, when the compression test is performed at a test temperature of 70 ° C. or higher, the compression set of the EPT vulcanizate rapidly increases. Further, even if the compounding amount of the synthetic rubber or filler having poor compatibility with the EPT in the EPT is increased,
The compression set of the T vulcanizate increases.

As described above, the EPT vulcanizate has abrasion resistance,
Inferior in compression set characteristics and a Shore A hardness of 37
It is difficult to produce a rubber roll having the following low hardness.

The applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. 9-176401 a rubber roll (rubber molded product for roll) having excellent abrasion resistance, heat aging resistance and compression set characteristics and having a Shore A hardness of 37 or less. ) Proposed.

This rubber roll is excellent in physical properties, abrasion resistance, heat aging resistance and compression set, and has Shore A
Although the hardness is as low as 37 or less, in production, further improvement in productivity by high-speed vulcanization is required.

Therefore, it is desired to develop a rubber composition for rolls which is excellent in abrasion resistance, heat aging resistance and compression set, has a low Shore A hardness of 37 or less, and has a higher vulcanization rate. ing.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, and is excellent in abrasion resistance, compression set characteristics and heat aging resistance, and has a Shore A hardness of 37 or less. It is an object of the present invention to provide a rubber composition for rolls having a low hardness and a higher vulcanization rate.

[0013]

The rubber composition for a roll according to the present invention comprises 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 from a rubber composition containing a random copolymer 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. ]

[0015]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the roll rubber according to the present invention will be specifically described.

The roll rubber according to the present invention is 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 structural unit derived from a triene compound.

Examples of the α-olefin having 3 to 20 carbon atoms include 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

[0020]

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 preferable, and 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 formula [1] include the following compounds.

Embedded image

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.

[0026]

Embedded image

[0027] (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 substantially does not 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].

[0030]

Embedded image ・ ・ ・ ・ (3)

[0031] (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 rubber composition for a roll has a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms (ethylene / α-olefin) of 9
9/1 to 30/70, preferably 75/25 to 50/5
0, more preferably in the range of 73/27 to 55/45.

When 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 is used, it has low hardness and excellent compression set characteristics. Thus, a composition that can provide a roll of rubber that has been obtained is obtained.

(Ii) The random copolymer rubber (A) that constitutes the rubber composition for a roll has a triene compound content of 0.5.
It is in the range of 1 to 30 mol%, preferably 0.5 to 7 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 roll rubber having excellent compression set characteristics, can be obtained.

As the third component of EPT, 4,8-dimethyl-
EPT in which 1,4,8-decatriene (hereinafter sometimes abbreviated as DMDT) is selected (hereinafter sometimes abbreviated as DMDT-EPT) and 5-ethylidene-2-norbornene (hereinafter abbreviated as ENB) EPT selected
(Hereinafter sometimes abbreviated as ENB-EPT) at the same third component content, DMDT-EPT is
The vulcanization rate is more than twice as fast.

[0036] Even if the content of ENB-EPT is increased, if it exceeds 4 mol%, the effect of improving the vulcanization rate is lost. On the other hand, DMDT-EPT can increase the vulcanization rate in proportion to the polyene content until its content reaches 7 mol%.

(Iii) The random copolymer rubber (A) constituting the rubber composition for a roll has an intrinsic viscosity [η] of 0.1 dl / g <[η] <10 dl / g measured in decalin at 135 ° C. ,
It is preferably in the range represented by 1.2 dl / g <[η] <3.5 dl / g, more preferably 1.2 dl / g <[η] <3.0 dl / g. By using the random copolymer rubber (A) having the intrinsic viscosity [η] in the above range, a roll rubber part excellent in mechanical strength can be provided.
A composition having excellent processability 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 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 -30 ° C. to 80 ° C., more preferably -20 ° C. to 60 ° C., and at a pressure of 5 MPa or less, preferably 2 MPa or less. However, the pressure is not zero.

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., and a pressure of 8 MPa or less, preferably 5 MPa 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. ~ 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 atoms 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. 10-147943.

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. 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 a proportion 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 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 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 a vulcanizing agent, 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. Such a vulcanization aid is used in an amount of 0.5 to 2 mol, preferably about equimolar, per 1 mol of the organic peroxide used.

In the production of the rubber roll according to the present invention, it is preferable to further use a vulcanization aid such as a metal activator, a compound having an oxymethylene structure and an anti-scorch agent.

Specific examples of the metal activator include magnesium oxide, zinc white, zinc carbonate, higher fatty acid zinc, lead red, litharge, calcium oxide and the like. These metal activators include a random copolymer rubber (A) 10
3 to 15 parts by weight, preferably 5 to 10 parts by weight per 0 parts by weight
Used in parts by weight.

In order to cope with various rubber processing steps, it is desirable to add a compound having an oxymethylene structure and a scorch inhibitor. Specific examples of the compound having an oxymethylene structure used in the present invention include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, and polypropylene glycol. These compounds having an oxymethylene structure are used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the random copolymer rubber (A).

As the scorch inhibitor, known scorch inhibitors can be used, and specific examples thereof include maleic anhydride and salicylic acid. These scorch inhibitors are used in an amount of 0.2 to 5 parts by weight, preferably 0.3 to 3 parts by weight, per 100 parts by weight of the random copolymer rubber (A).
Used in parts by weight.

Filler (C) The filler (C) used in the present invention includes a filler having a reinforcing property and a filler having no reinforcing property.

As the rubber reinforcing agent, specifically, SR
F, GPF, FEF, HAF, ISAF, SAF, F
Various carbon blacks such as T and MT, finely divided silicic acid, and various short fibers such as glass short fibers, cotton short fibers, polyester short fibers, nylon short fibers, and aramid short fibers.

Examples of the filler having no reinforcing property include light calcium carbonate, heavy calcium carbonate, talc, clay, silica and the like. The type and amount of these rubber reinforcing agents and fillers can be appropriately selected depending on the application, but the amount is usually up to 300 parts by weight, usually 100 parts by weight of random copolymer rubber (A), preferably Maximum is 200 parts by weight.

Other Components In the rubber composition for a roll used in the present invention, in addition to the above random copolymer rubber (A), vulcanizing agent (B) and filler (C), Vulcanization accelerators and vulcanization aids can be added, but in addition, antioxidants, processing aids, heat stabilizers, weather stabilizers, antioxidants, antistatic agents, coloring agents, lubricants, plasticizers And other rubber compounding agents can be compounded within a range that does not impair the object 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 rubber composition for a roll used in the present invention can be prepared, for example, by the following method.

That is, the rubber composition for a roll used in the present invention is prepared by adding necessary additives such as a random copolymer rubber (A), a filler (C) and a plasticizer using a mixer such as a Banbury mixer. About 3 at 80-170 ° C
After kneading for 10 to 10 minutes, a vulcanizing agent (B) and, if necessary, an antioxidant, a vulcanization accelerator or a vulcanization aid are additionally mixed using rolls such as an open roll, After kneading at 40-80 ° C for 5-30 minutes, dispensing,
A ribbon or sheet compound rubber is prepared.

Next, the compounded rubber prepared as described above is generally dispensed using a roll machine, a calendering machine, an extruder or the like, and wound around a metal core coated with an adhesive. The circumference of the roll that finished the rubber winding is helically tightened with a cloth, and a suitable plate is applied to both ends of the roll.In some cases, a wire is tightly wound on the above-mentioned cloth and put in a vulcanizer, Vulcanization is performed by heating to 130 to 220 ° C. After the vulcanized roll is completely cooled, the cloth and wire are removed and mechanical polishing is performed to finish.

Alternatively, the compounded rubber may be extruded into a tube using an extruder, and then vulcanized through a metal core coated with an adhesive inside the extruded tube.
The rubber roll manufactured as described above has excellent heat aging resistance, excellent performance in dynamic fatigue resistance (bending fatigue resistance), and a small change in elastic modulus from low to high temperatures.

[0079]

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 with the triene compound content and the intrinsic viscosity [η] are in specific ranges, they have excellent low-hardness such as abrasion resistance, compression set characteristics and heat aging resistance, and a Shore A hardness of 37 or less, And the vulcanization speed is fast.

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

The evaluation test method for unvulcanized rubber and vulcanized rubber in the examples and comparative examples is 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. Further, according to JIS K6251 from the unvulcanized sheet having a thickness of 2 mm of the compounded rubber,
No. Dumbbell-shaped test piece was punched out and pulled at a speed of 100 mm /
A tensile test was performed at 23 ° C. for 30 minutes to determine the yield point strength, which was used as a measure of the shape retention of the unvulcanized rubber.

[2] Tensile test A vulcanized rubber sheet was punched out and punched according to 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 performed under the condition of 0 mm / min, and a tensile break stress T _B (1) and a tensile break elongation E _B (1) 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] Aging test The aging test was carried out at 150 ° C. for 3 days by air heating aging.
The measurement was carried out in accordance with SK 6257 (1993), and the tensile break stress T _B (2), the tensile break elongation E _B (2), and the change rate ΔH _A of Shore A hardness were determined.

[5] Compression Set Test The compression set test is based on JIS K 6262 (1993).
The compression set (C _S ) was determined under the conditions of 100 ° C. and −10 ° C. for 72 hours.

[6] Wear test According to ASTM D2228, a vulcanized test piece was prepared from the above compounded rubber, and a pico abrasion test was performed to determine a wear index.

The random copolymer rubber (EPT) used in the examples and comparative examples is as shown in Table 1.

[0088]

[Table 1]

[0089]

Example 1 Ethylene / propylene / 4,8 shown in Table 1
-Dimethyl-1,4,8-decatriene copolymer rubber (copolymer (1)) was compounded according to Table 2 to obtain an unvulcanized compound rubber.

[0090]

[Table 2]

That is, the above-mentioned copolymer (1), zinc white, stearic acid, FEF carbon black and process oil were kneaded for 5 minutes using a 1.7 liter Banbury mixer [manufactured by Kobe Steel Ltd.]. Then, it was left at room temperature for one day. A vulcanization accelerator and sulfur (vulcanizing agent) were added to the kneaded product thus obtained using an open roll and kneaded, and the compounded rubber was separated to obtain a compounded rubber sheet having a thickness of about 2 mm. In this case, the roll surface temperature is 50
° C, the back roll was 60 ° C. The roll rotation speed was 16 rpm for the front roll and 18 rpm for the rear roll.

After the above rubber sheet was wound around a hollow pipe-shaped metal core (SUS 304) having an outer diameter of 60 mm, the surface of the rubber sheet was spirally wound with a tightening cloth (glass fiber tape). Vulcanization was performed for 20 minutes. After completion of vulcanization, the mixture was cooled and the vulcanized rubber portion was peeled off from the metal core, and a No. 3 dumbbell-shaped test piece according to JIS K6251 was punched from the vulcanized rubber. Next, the stress at break T
_B (1) and elongation at break E _B (1) were measured. Further, the Shore A hardness _HA of the vulcanized product was measured. Further, for the unvulcanized rubber composition before performing the above vulcanization,
According to the above method, t _c (90) and t ₅ were determined.

Next, the above-mentioned No. 3 dumbbell-shaped test piece was
After aging according to the above method, the stress at break T
_B (2), elongation at break E _B (2), and change rate ΔH _A of Shore A hardness were measured.

Further, from the above-mentioned compounded rubber for rolls,
A vulcanized test specimen having a diameter of 2.7 mm and a diameter of 29.0 mm was prepared.
A compression set (C _s ) test was performed according to the above method.

Further, a vulcanized test piece was prepared from the compounded rubber according to the above method, and a pico abrasion test was performed to determine a wear index.

Table 4 shows the results.

[0097]

Example 2 In Example 1, except that the copolymer (2) shown in Table 1 was used instead of the copolymer (1),
Performed in the same manner as in Example 1.

Table 4 shows the results.

[0099]

Examples 3 and 4 In Example 1, copolymers (3) and (4) shown in Table 1 above were used instead of copolymer (1), and the blending was changed as shown in Table 3. The procedure was performed in the same manner as in Example 1.

[0100]

[Table 3]

[0101]

Comparative Examples 1 and 2 The procedure of Example 1 was repeated, except that the copolymers (5) and (6) were used in place of the copolymer (1).

Table 4 shows the results.

[0103]

[Table 4]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 7/16 C08K 7/16 F16C 13/00 F16C 13/00 AB F Term (Reference) 3J103 FA01 FA02 FA13 FA15 GA02 HA03 HA12 HA53 4J002 AB012 BB051 BB151 CF002 CL012 CL062 DA037 DA046 DD006 DJ017 DL007 EK016 EK036 EK046 EV046 EV166 FA042 FA047 FD146 FD150 GM00 4J100 AA02P AA03Q AA04 AAQAAAQ19AAQ19

Claims (1)

[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
The rubber composition for rolls is 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. ]