JP2001164107A - Rubber composition and crosslinked material thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition which is excellent in the workability such as the extrudability and is capable of obtaining a flat surface skin and also has a sufficiently low and stable volume specific resistivity; a crosslinkable rubber composition; and a crosslinked material which is formed by crosslinking it and is suitable for a use as rolls. SOLUTION: The rubber composition, the crosslinkable rubber composition, comprises an epihalohydrin-based ring opening copolymerized rubber (1) containing 35-100 mole % of an epihalohydrin monomer (a) units and 0-65 mole % of an alkylene oxide monomer (b) units and an ethylene oxide-based ring opening copolymerized rubber (2) which contains 70-99 mole % of an ethylene oxide (c) units and 30-1 mole % of an oxirane monomer (d) units exclusive of ethylene oxide and which has a crosslinkable oxirane monomer units content of 15 mole % or less and a Mooney viscosity of 20-200, with containing the epihalohydrin-based ring opening copolymerized rubber (1) of 40-95 wt.% relative to the sum total weight of the epihalohydrin-based ring opening copolymerized rubber (1) and the ethylene oxide-based ring opening copolymerized rubber (2). The crosslinked material is formed by adding a crosslinker to the above composition and by crosslinking the added composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition containing a crosslinkable epihalohydrin ring-opening copolymer rubber, a crosslinkable rubber composition containing the rubber and a crosslinking agent, and a crosslinked product obtained by crosslinking the crosslinkable rubber. About.

[0002]

2. Description of the Related Art Epihalohydrin ring-opening copolymer rubbers are
It is a ring-opened polymer rubber of an oxirane monomer having an epihalohydrin unit as a main structural unit, and has excellent oil resistance, heat resistance, weather resistance, ozone resistance, compression set resistance and the like. Epihalohydrin ring-opening copolymer rubbers have been
It is widely used as a material for various molded products such as tubes and diaphragms. Some epihalohydrin ring-opening copolymer rubbers have low electric resistance, and their use as conductive materials has been proposed.

For example, a ring-opened copolymer rubber of an oxirane monomer containing an alkylene oxide monomer unit, an epihalohydrin monomer unit and an ethylenically unsaturated epoxide monomer unit is formed on the surface of a roll-shaped substrate. A method of providing a crosslinked product of a rubber composition containing a saturated rubber has been proposed (JP-A-8-292640). The thus obtained rubber roll can be used as a low-hardness OA roll that is less likely to contaminate the photoreceptor, has a low electric resistance, has a small environmental dependence of the electric resistance. However, there has been a demand for a rubber roll material that is more excellent in workability, has lower friction resistance on the surface of the obtained rubber roll, and has a lower volume specific resistance value.

A conductive rubber composition containing an epihalohydrin ring-opening copolymer rubber and ethylene glycols is also known (Japanese Patent Publication No. 3-78429). The crosslinked product has no bleed, is easy to color, has ozone resistance,
It can also be selected for weather resistance. However, the compression set is large,
When the environment changes from high temperature and high humidity to low temperature and low humidity, bleeding may occur, and its use as a roll is limited.

Further, a rubber composition in which an ethylene oxide-based ring-opening copolymer rubber is blended with a diene-based rubber is known as a conductive rubber composition (WO 97/39055). This rubber has excellent low heat build-up as a tire material,
While it has excellent tensile strength and workability and can also provide antistatic performance, it has good rollability with regard to workability, but there is no known workability other than rollability such as extrudability. Further, although the antistatic performance of the tire is sufficient, the volume specific resistance value of rubber used for OA rolls and belts, which require semiconductivity, was insufficient.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber composition having excellent processability such as extrudability, capable of obtaining a smooth surface skin, having a sufficiently low and stable volume resistivity, It is an object of the present invention to provide a crosslinked product suitable for use as a functional rubber composition and a roll obtained by crosslinking the same.

The present inventors have conducted intensive studies with the aim of achieving the above object, and as a result, have found that an epihalohydrin-based ring-opening copolymer obtained by ring-opening polymerization of an epihalohydrin monomer (a) and an alkylene oxide monomer (b). A rubber composition comprising a rubber (1) and an ethylene oxide-based ring-opening copolymer rubber (2) obtained by ring-opening polymerization of ethylene oxide (c) and an oxirane monomer (d) other than ethylene oxide has an extrudability. Excellent, as a result, a smooth surface skin was obtained, and the crosslinked product obtained by crosslinking it was found to have low volume resistivity, low compression set, and low surface friction coefficient. Based on the above, the present invention has been completed.

[0008]

Thus, according to the present invention, from 35 to 100 mol% of epihalohydrin monomer (a) units and from 0 to 6 units of alkylene oxide monomer (b) units.
Epihalohydrin ring-opening copolymer rubber (1) containing 5 mol% and 70 to 99 mol% of ethylene oxide (c) units
And oxirane monomers other than ethylene oxide (d)
Containing 30 to 1 mol% of a unit, having a crosslinkable oxirane monomer unit content of 15 mol% or less, and having a Mooney viscosity of 20 to
And an epihalohydrin ring-opening copolymer rubber (2) based on the total weight of the epihalohydrin ring-opening copolymer rubber (1) and the ethylene oxide ring-opening copolymer rubber (2). Copolymer rubber (1) is 4
0.1 to 95% by weight of a rubber composition, and 100 parts by weight of a rubber component containing the rubber composition as a main component, a crosslinking agent in an amount of 0.1%
Provided are a crosslinkable rubber composition containing from 10 to 10 parts by weight and a crosslinked product obtained by crosslinking the crosslinkable rubber composition.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION [Rubber Composition] The rubber composition of the present invention comprises 35 to 100 epihalohydrin monomer (a) units.
Mol% and alkylene oxide monomer (b) unit 0
Epihalohydrin ring-opening copolymer rubber (1) containing 65 mol%, 70-99 mol% of ethylene oxide (c) units and 30-1 mol% of oxirane monomer (d) units other than ethylene oxide, and crosslinked An ethylene oxide-based ring-opening copolymer rubber (2) having a water-soluble oxirane monomer unit content of 15 mol% or less and a Mooney viscosity of 20 to 200, and an epihalohydrin-based ring-opening copolymer rubber (1) and an ethylene oxide-based ring-opening The epihalohydrin ring-opening copolymer rubber (1) accounts for 40 to 95% by weight based on the total weight of the copolymer rubber (2).

Epihalohydrin ring-opening copolymer rubber (1)
And the ethylene oxide-based ring-opening copolymer rubber (2) contains a ring-opening copolymer rubber of an oxirane monomer.

The oxirane monomer is a monomer having a three-membered ring ether structure. The ring-opening copolymer rubber of an oxirane monomer is a rubber composed of oxirane monomer units whose three-membered ring ether structure is ring-opened.

The oxirane monomer is a monomer in which at least one of ethylene oxide and hydrogen of ethylene oxide is substituted by a substituent. The substituent is not particularly limited, but the nature of the monomer differs depending on the type of the substituent.

For example, an oxirane monomer is a crosslinkable oxirane monomer in which at least one of the hydrogens of ethylene oxide is substituted by a substituent capable of forming a bridge structure by reacting with a crosslinking agent after ring-opening polymerization. And other non-crosslinkable oxirane monomers.

Examples of the crosslinkable oxirane monomer include halogen-substituted oxirane monomers and ethylenically unsaturated oxirane monomers. The halogen-substituted oxirane monomer is a monomer in which the aforementioned substituent contains a halogen, and includes epihalohydrin such as epichlorohydrin, epibromohydrin, epiiodohydrin, epifluorohydrin, and β-methylepichlorohydrin. Monomer (a);
And p-chlorostyrene oxide, dibromophenyl glycidyl ether and the like. The ethylenically unsaturated oxirane monomer has the above-mentioned substituent having an ethylenically unsaturated bond, and includes vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allyl phenyl glycidyl ether and the like. Mono-epoxides of diene or polyene such as butadiene monoepoxide, 4,5-epoxy-2-pentene, 1,2-epoxy-5,9-cyclododecadiene; 3,4-
Alkenyl epoxides such as epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene; glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl-4-
Of ethylenically unsaturated carboxylic acids such as heptenoate, glycidyl sorbate, glycidyl linoleate, glycidyl-4-methyl-3-pentenoate, glycidyl ester of 3-cyclohexenecarboxylic acid, glycidyl ester of 4-methyl-3-cyclohexenecarboxylic acid Glycidyl ester; and the like.

Examples of the non-crosslinkable oxirane monomer include an alkylene oxide monomer (b), an alicyclic epoxide monomer, an alkyl glycidyl ether monomer, and a non-ethylenically unsaturated epoxide monomer. . The alkylene oxide monomer (b) is ethylene oxide or one in which the above-mentioned substituent is an alkyl group, such as ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxy-isobutane, 3-epoxybutane, 1,2-epoxyhexane, 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane,
1,2-epoxyoctadecane and the like. In the alicyclic epoxy monomer, the above-mentioned substituent is a hydrocarbon group, and the substituent is bonded to two carbons of a three-membered ring ether structure. Is a compound having a three-membered ring ether structure,
-Epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-epoxycyclododecane and the like. Alkyl glycidyl ether monomer, the above-mentioned substituent is an alkyloxymethyl group, methyl glycidyl ether, ethyl glycidyl ether,
Butyl glycidyl ether and the like. The non-ethylenically unsaturated epoxide monomer has the above-mentioned substituent having no ethylenically unsaturated bond and having a non-ethylenically unsaturated bond, and examples thereof include styrene oxide and phenylglycidyl ether. .

In the present invention, in order to obtain a ring-opening copolymer rubber of an oxirane monomer, a polymer such as butadiene dioxide, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, or vinylcyclohexene dioxide is used. A diepoxy monomer for introducing a branched structure may be copolymerized.

(Epihalohydrin Ring-Opening Copolymer Rubber (1)) The epihalohydrin ring-opening copolymer rubber (1) used in the present invention is a ring-opening polymer of epihalohydrin monomer (a) alone or epihalohydrin monomer. A ring-opening copolymer of (a) and an alkylene oxide monomer (b), comprising 35 units of epihalohydrin monomer (a)
It contains not less than mol% and not more than 65 mol% of alkylene oxide monomer (b) units.

The epihalohydrin monomer (a) includes:
Epichlorohydrin is preferred.

As the alkylene oxide monomer (b), ethylene oxide, propylene oxide and the like are preferred.

Epihalohydrin ring-opening copolymer rubber (1)
The lower limit of the epihalohydrin monomer (a) unit to all monomer units constituting is 35 mol%, preferably 37 mol%, more preferably 39 mol%, and the upper limit is preferably 85 mol%, Preferably it is 70 mol%.
If the unit content of the epihalohydrin monomer (a) in the epihalohydrin-based ring-opening copolymer rubber (1) is too small, the hygroscopicity of the crosslinked product increases, and if it is too large, the volume resistivity of the crosslinked product may increase. is there.

Epihalohydrin ring-opening copolymer rubber (1)
Is preferably 15 mol%, more preferably 25 mol%, and the upper limit is 65 mol%, preferably 60 mol%, based on the total monomer units constituting , More preferably 58 mol%
It is. If the unit content of the alkylene oxide monomer (b) in the epihalohydrin ring-opening copolymer rubber (1) is too small, the unit content of the epihalohydrin monomer (a) will be too large, and the volume resistivity of the crosslinked product will be too high. May be high, and if too large, the crosslinked product has high hygroscopicity, and
Depending on the environment, the cross-linked product may not be used depending on the environment, because the volume resistivity of the crosslinked product is greatly dependent on the environment.

Epihalohydrin ring-opening copolymer rubber (1)
Is preferably one containing an ethylenically unsaturated epoxide monomer (e) unit, and as the ethylenically unsaturated epoxide monomer (e), allyl glycidyl ether is preferable.

Epihalohydrin ring-opening copolymer rubber (1)
The lower limit of the ethylenically unsaturated epoxide monomer (e) unit to all the monomer units constituting is preferably 2 mol%, more preferably 2.5 mol%, particularly preferably 3 mol%, and the upper limit. Is preferably 15 mol%, more preferably 12 mol%, particularly preferably 10 mol%.
If the unit content of the ethylenically unsaturated epoxide monomer (b) is too small, the crosslinked product may be inferior in ozone resistance and difficult to use, and if too large, the hardness of the crosslinked product becomes too high. There is. Further, when the rubber composition is crosslinked with a sulfur-based crosslinking agent or an organic peroxide-based crosslinking agent,
The unit of the ethylenically unsaturated epoxide monomer (e) in the epihalohydrin ring-opening copolymer rubber (1) is indispensable, and if the content is too small, it may not be crosslinked.

Epihalohydrin ring-opening copolymer rubber (1)
The lower limit of the Mooney viscosity of is preferably 20, more preferably 30, and particularly preferably 35, and the upper limit is preferably 150, more preferably 120, and particularly preferably 1
00. Epihalohydrin ring-opening copolymer rubber (1)
If the Mooney viscosity is too low, the shape retention at the time of molding is inferior, or the tackiness becomes strong. If the Mooney viscosity is too high, the fluidity at the time of molding is inferior, and the dimensional stability also decreases.

(Ethylene oxide ring-opening copolymer rubber (2)) The ethylene oxide ring-opening copolymer rubber (2) used in the present invention has an ethylene oxide (c) unit of 70 to 99.
% Of oxirane monomer (d) units other than ethylene oxide, 30 to 1 mol%, a crosslinkable oxirane monomer unit content of 15 mol% or less, and a Mooney viscosity of 20 to 200.

Ethylene oxide ring-opening copolymer rubber (2)
Is lower than 70 mol%, preferably 75 mol%, more preferably 80 mol%, and the upper limit is 99 mol%, preferably 97 mol%. Mol%, more preferably 95 mol%. If the content of the ethylene oxide (c) unit in the ethylene oxide ring-opening copolymer rubber (2) is too small, the surface friction resistance and the volume specific resistance of the crosslinked product of the present invention are too large. In the production of the polymer, the ethylene oxide-based ring-opening copolymer rubber (2) has a rubber-like property, so that a problem such as crumb cohesion occurs in the step of separating the polymer from the solvent, or the polymer particles during storage. May be fixed. On the other hand, if the content of the ethylene oxide (c) unit in the ethylene oxide-based ring-opening copolymer rubber (2) is too large, the main chain of the ethylene oxide-based ring-opening copolymer rubber (2) tends to crystallize, and the crosslinked product of the present invention Increases the specific volume resistivity or increases the hardness of the crosslinked product.

Ethylene oxide ring-opening copolymer rubber (2)
The lower limit of the content of the oxirane monomer (d) other than ethylene oxide to all the monomer units constituting is 1 mol%, preferably 3 mol%, more preferably 5 mol%, and the upper limit is 30 mol%. %, Preferably 20 mol%, particularly preferably 15 mol%. If the content of the oxirane monomer (d) unit other than ethylene oxide in the ethylene oxide-based ring-opening copolymer rubber (2) is too small, the content of the ethylene oxide monomer (c) unit increases, and the copolymer rubber ( The main chain of 2) is easily crystallized, and the crosslinked product of the present invention has a large volume resistivity value and the crosslinked product has high hardness. On the other hand, if the content of the oxirane monomer (d) other than ethylene oxide in the ethylene oxide-based ring-opening copolymer rubber (2) is too large, the surface friction resistance and the volume resistivity of the crosslinked product of the present invention are too large. In addition, in the production of a polymer by the solvent slurry polymerization method, since the properties of the ethylene oxide-based ring-opening copolymer rubber (2) become rubbery, problems such as crumb cohesion in the step of separating the polymer from the solvent may occur. Or a problem such as sticking of the polymer particles during storage.

Ethylene oxide ring-opening copolymer rubber (2)
Is preferably 1 mol%, more preferably 2 mol%, and the upper limit is 15 mol%, preferably 13 mol%.
Mol%, more preferably 11 mol%. If the content of the crosslinkable oxirane monomer unit in the ethylene oxide-based ring-opening copolymer rubber (2) is too small, crosslinking of the ethylene oxide-based ring-opening copolymer rubber (2) cannot be performed, and the strength properties of the obtained cross-linked product are reduced. May be lower. On the other hand, if the content of the crosslinkable oxirane monomer unit in the ethylene oxide ring-opening copolymer rubber (2) is too large, the hardness of the crosslinked product becomes too high,
Elongation tends to decrease.

Ethylene oxide ring-opening copolymer rubber (2)
The lower limit of Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 2
It is 0, preferably 30, more preferably 40, and the upper limit is 200, preferably 170, more preferably 150. Ethylene oxide ring-opening copolymer rubber (2)
If the Mooney viscosity is too low, the shape retention of the crosslinkable rubber composition of the present invention at the time of molding is inferior, and if too high, the flowability at the time of molding the crosslinkable rubber composition is inferior, and the dimensional stability also decreases. I do.

(Rubber ratio) Assuming that the total weight of the epihalohydrin ring-opening copolymer rubber (1) and the ethylene oxide ring-opening copolymer rubber (2) in the rubber composition of the present invention is 100 parts by weight, The lower limit of the epihalohydrin ring-opening copolymer rubber (1) in the rubber composition of the present invention is 40 parts by weight, preferably 50 parts by weight, more preferably 60 parts by weight,
The upper limit is 95 parts by weight, preferably 90 parts by weight, more preferably 85 parts by weight. The lower limit of the content of the ethylene oxide ring-opening copolymer rubber (2) in the rubber composition is 5
Parts by weight, preferably 10 parts by weight, more preferably 15 parts by weight, and the upper limit is 60 parts by weight, preferably 50 parts by weight, more preferably 40 parts by weight. If the amount of the epihalohydrin-based ring-opening copolymer rubber (1) in the rubber composition is too large and the amount of the ethylene oxide-based ring-opening copolymer rubber (2) is too small, the shrinkage at the time of molding is increased, and the surface skin is smooth. On the other hand, if the amount of the epihalohydrin ring-opening copolymer rubber (1) is too small, and if the amount of the ethylene oxide-based ring-opening copolymer rubber (2) is too large, the hardness of the crosslinked product may become high. Depending on the environment, it may not be possible to use the material due to too high hygroscopicity.

[Crosslinkable Rubber Composition] The crosslinkable rubber composition of the present invention contains the rubber composition of the present invention and a crosslinking agent.

Examples of the crosslinking agent include sulfur or sulfur donors, organic peroxides, mercaptotriazines, thioureas and the like. Examples of the sulfur donor include thiurams such as morpholine disulfide and tetramethylthiuram disulfide. When sulfur or a sulfur donor is used, a crosslinked product having a low volume resistivity is obtained. Examples of the organic peroxide include ketone peroxides, peroxyesters, diacyl peroxides, and alkyl peroxides.When these organic peroxides are used, a crosslinked product having good compression set resistance is obtained. can get. Examples of thioureas include thiourea, dibutylthiourea, and triethylthiourea.

The amount of the crosslinking agent is determined based on the amount of the rubber component contained in the rubber composition. The rubber component is an epihalohydrin ring-opening copolymer rubber (1)
When not only the ethylene oxide-based ring-opening copolymer rubber (2) but also other rubbers are compounded in the rubber composition as described later, the term also includes the compounded rubber.

The lower limit of the amount of the crosslinking agent per 100 parts by weight of the rubber component is preferably 0.1 part by weight, more preferably 0.2 part by weight, and particularly preferably 0.3 part by weight.
The upper limit is preferably 10 parts by weight, more preferably 7 parts by weight, particularly preferably 5 parts by weight.

In the present invention, if necessary, a crosslinking aid can be used together with a crosslinking agent. The crosslinking assistant is not particularly limited.

Examples of the crosslinking aid used in combination with sulfur or a sulfur donor include a thiuram accelerator, a thiazole accelerator, and a sulfenamide accelerator.
Examples of the thiuram-based accelerator include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide and the like. Examples of the thiazole accelerator include 2-mercaptobenzothiazole and dibenzothiazyl disulfide.
Examples of the sulfenamide-based accelerator include N-cyclohexyl-2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide and the like. These crosslinking aids may be used in combination of two or more. The upper limit of the amount of the crosslinking aid used per 100 parts by weight of the rubber component is preferably 15 parts by weight, more preferably 12 parts by weight, and particularly preferably 10 parts by weight. If the amount of the crosslinking aid is too large, the crosslinking rate becomes too fast during crosslinking, or blooms on the surface of the crosslinked product occur.

The crosslinking aid used in combination with the organic peroxide crosslinking agent includes metal oxides such as zinc oxide and magnesium oxide; metal hydroxides such as calcium hydroxide; metals such as zinc carbonate and basic zinc carbonate. Carbonates; fatty acids such as stearic acid and oleic acid; and fatty acid metal salts such as zinc stearate and magnesium stearate. When an organic peroxide is used, a compound having at least two crosslinkable unsaturated bonds in the molecule can be used. Specific examples thereof include ethylene dimethacrylate, diallyl phthalate, N, Nm-phenylenedimaleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate, and liquid vinyl polybutadiene. Two or more of these crosslinking assistants can be used in combination. Rubber component 10
The upper limit of the amount of the crosslinking aid per 0 parts by weight is preferably 20 parts by weight, more preferably 15 parts by weight, and particularly preferably 10 parts by weight. If the amount of the crosslinking aid is too large, the crosslinking rate may be too high during crosslinking, bloom may occur on the surface of the crosslinked product, or the crosslinked product may be too hard.

(Compound) As long as the properties of the rubber composition or the crosslinkable rubber composition of the present invention are not impaired, natural rubber, polybutadiene rubber, polyisoprene rubber, acrylic rubber,
Rubbers other than epihalohydrin ring-opening copolymer rubber (1) and ethylene oxide ring-opening copolymer rubber (2), such as styrene-butadiene rubber, acrylonitrile-butadiene rubber, and chloroprene rubber; olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers Thermoplastic elastomers such as vinyl chloride-based elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer;
Resins such as polyvinyl chloride, coumarone resin and phenol resin may be blended.

Epihalohydrin ring-opening copolymer rubber (1)
These rubbers, thermoplastic elastomers and resins may be compounded in a total amount of up to 100 parts by weight based on 100 parts by weight of the total weight of the ethylene oxide-based ring-opening copolymer rubber (2).

The rubber composition of the present invention may contain an inorganic oxide as a filler. Silicon as an inorganic oxide,
Examples include oxides of aluminum, calcium, zinc, titanium, and magnesium, and these may be used alone or in combination of two or more. Among them, silica, which is an oxide of silicon, is particularly preferable because it has a high affinity for the ethylene oxide-based ring-opening copolymer rubber (2) and the strength properties of the rubber composition are high. Among silicas, BET is an index of the specific surface area per unit weight.
Silica having an adsorption surface area of 100 to 200 m ² / g,
It is preferable because a rubber composition excellent in the processability of the rubber composition and the properties of the crosslinked product can be obtained. The silica preferably has a pH of 7 or more, more preferably 8 or more, and particularly preferably 9 or more. If the pH of the silica is too low, the volume resistivity of the crosslinked product may increase.

The lower limit of the amount of the inorganic oxide to 100 parts by weight of the rubber component is preferably 1 part by weight, more preferably 2 parts by weight, and particularly preferably 4 parts by weight.
The upper limit is preferably 200 parts by weight, more preferably 15 parts by weight.
0 parts by weight, particularly preferably 100 parts by weight.

The rubber composition may contain an alkali metal salt or an alkaline earth metal salt. The ring-opening copolymer of the two types of oxirane monomers used in the present invention is also an ion-conductive polymer, and exhibits a property that the volume resistivity decreases significantly when an alkali metal ion or an alkaline earth metal ion is introduced. Have. Any alkali metal salt or alkaline earth metal salt may be used as long as it is soluble in the ethylene oxide ring-opening copolymer rubber (2) of the present invention or its crosslinked product. For example, chloride ion, bromine ion, iodine ion, perchlorate ion, thiocyanate ion, tetrafluoroboronate ion, nitrate ion, AsF ₆ −, P
F ₆ -, selected stearyl sulfonate ion, octylsulfonate ion, dodecylbenzenesulfonate ion, naphthalenesulfonate ion, dodecyl naphthalenesulfonate ion, etc. tetracyano -p- quinodimethane ion Anions and Li, N
a, K, Rb, Cs, Mg, Ca, and a salt composed of an alkaline earth metal ion selected from Mg and Ca. These alkali metal salts or alkaline earth metal salts may be used in combination of two or more.

Ethylene oxide ring-opening copolymer rubber (2)
The lower limit of the amount of the alkali metal salt or alkaline earth metal salt used per 100 parts by weight is preferably 0.01 part by weight, more preferably 0.1 part by weight, particularly preferably 0.1 part by weight.
It is 5 parts by weight, and the upper limit is preferably 10 parts by weight, more preferably 5 parts by weight, and particularly preferably 3 parts by weight.
If the used amount of the alkali metal salt is too small, the volume resistivity may not be sufficiently small, and if it is too large, the alkali metal salt does not sufficiently dissolve in the rubber composition and bleeds out from a crosslinked product of the rubber composition. There are cases.

The rubber composition or the crosslinkable rubber composition of the present invention may further contain, if necessary, a reinforcing material, an antioxidant, an antioxidant, and the like, as long as the effects and objects of the present invention are not impaired. Additives such as agents, light stabilizers, anti-scorch agents, crosslinking retarders, plasticizers, processing aids, lubricants, adhesives, lubricants, flame retardants, fungicides, antistatic agents, colorants, etc. be able to.

(Preparation of Composition) The rubber composition or the crosslinkable rubber composition of the present invention is prepared by mixing the above-mentioned components by an appropriate mixing method such as roll mixing, Banbury mixing, screw mixing, and solution mixing. Can be prepared. The order of compounding is not particularly limited, but after components that are hardly decomposed by heat (for example, epihalohydrin ring-opening copolymer rubber (1), ethylene oxide ring-opening copolymer rubber (2), etc.) are sufficiently mixed, heat is applied. A component that easily reacts or decomposes (for example, a cross-linking agent, a cross-linking accelerator, etc.) may be mixed in a short time as possible.

(Molding and Crosslinking) The method for molding and the method for crosslinking the crosslinkable rubber composition of the present invention are not particularly limited, but the rubber composition of the present invention is suitable for extrusion molding. If necessary, such as the molding method, the crosslinking method, the shape of the crosslinked product,
Molding and crosslinking may be performed simultaneously, or crosslinking may be performed after molding.

The crosslinkable rubber composition of the present invention can be crosslinked by heating. The lower limit of the heating temperature at that time is preferably 130 ° C., more preferably 140 ° C.
And the upper limit is preferably 200 ° C. If the temperature is too low, a long crosslinking time may be required or the crosslinking density may be low. If the temperature is too high, crosslinking may proceed in a short time, and molding failure may occur.

The crosslinking time is determined by the crosslinking method, crosslinking temperature,
Although it depends on the shape and the like, a range of 1 minute or more and 5 hours or less is preferable from the viewpoint of the crosslinking density and the production efficiency.

As a heating method, a method used for rubber crosslinking, such as press heating, steam heating, oven heating, or hot air heating, may be appropriately selected.

[Crosslinked Product] The crosslinked product of the rubber composition of the present invention can be used in a wide variety of fields such as OA equipment such as printers and copiers, printing, general equipment / equipment, electronics / electricity, and construction. It is useful as belts, drum materials, coating materials, protective materials, and the like.

(Rubber Roll) Hereinafter, the crosslinked product will be described with reference to a rubber roll exhibiting the best effects of the present invention.

By forming the crosslinked product of the present invention on the outer peripheral surface of the shaft, a rubber roll having a rubber layer having an electric resistance in a medium resistance region can be obtained. The lower limit of the volume resistivity value of the crosslinked material used for the rubber layer having the electric resistance in the medium resistance region is
Preferably 10 ⁵ Ω · cm, more preferably 10 ^5.5
Ω · cm, particularly preferably 10 ⁶ Ω · cm, and the upper limit is preferably 10 ¹² Ω · cm, more preferably 10 ¹² Ω · cm.
^{It is 11} Ω · cm, particularly preferably 10 ¹⁰ Ω · cm. If the volume resistivity is too small, the roll may not be easily charged. If the volume resistivity is too large, the charged amount may be too large. In either case, the image may be unclear.

The lower limit of the hardness (Duro-A) of the crosslinked product used for the rubber layer having the electric resistance in the medium resistance region is preferably 10, more preferably 15, and particularly preferably 20, and the upper limit is preferably 80, more preferably 70,
Particularly preferably, it is 60. If the hardness of the crosslinked product is too low, the tackiness increases or the amount of deformation increases, and the image tends to be unclear. If the hardness is too high, the contact area with the photoconductor decreases, and the photoconductor may be damaged. .

Further, the thickness of the rubber layer of the electric resistance in the medium resistance region is not particularly limited, but the lower limit of the layer thickness is preferably 10 μm, more preferably 50 μm, and particularly preferably 1 μm.
The upper limit is preferably 15 mm, more preferably 10 mm, and particularly preferably 8 mm. If the layer thickness is too small, the durability against abrasion may decrease.If the layer thickness is too large, the amount of charge required during image formation becomes large, so that the image becomes unclear or the image forming apparatus needs to be large. May be.

The method of forming the roll is not particularly limited. For example, the rubber composition of the present invention is extruded simultaneously with the shaft using a single-screw or multi-screw extruder, and a semiconductive material is formed on the outside of the shaft. After forming a conductive rubber layer, a method of crosslinking by heating, injection molding machine, extrusion blow molding machine, transfer molding machine,
Molded with a mold using a press molding machine, crosslinked,
A method of laminating on a shaft body may be used. Among them, it is most suitable to perform molding using an extruder.

The roll of the present invention may have a conductive base layer between the shaft and the rubber layer of the electric resistance in the medium resistance region. The conductive base layer is not particularly limited, but is preferably a conductive elastic body. For example, a cross-linked product obtained by cross-linking a composition obtained by compounding a conductivity imparting agent with rubber or a foam obtained by foaming,
Examples of the composition include a composition obtained by blending a conductivity imparting agent with a thermoplastic elastomer. As the rubber, acrylonitrile-butadiene rubber, epichlorohydrin rubber, ethylene propylene rubber, polybutadiene rubber or the like is used alone or as a mixture. Examples of the conductivity-imparting agent include carbon black such as acetylene black, conductive metal compounds such as conductive tin oxide and conductive zinc oxide, and surfactants. The upper limit of the volume resistivity of the conductive base layer is preferably 10 ⁶ Ω · cm, more preferably 10 ⁶ Ω · cm.
^{It is 5} Ω · cm, particularly preferably 10 ⁴ Ω · cm.

The roll of the present invention may further have a protective layer on the outside of the rubber layer of the electric resistance in the medium resistance region as long as the properties of the rubber layer are not impaired. As the protective layer, a resin layer or a rubber layer is used, and a resin layer or a rubber layer having an electric resistance in a medium resistance region is preferable.

The resin constituting the protective layer is not particularly limited, and resins used as the protective layer in a general rubber roll having an electric resistance in a medium resistance region, for example, polyurethane resin, silicone resin, polyamide resin, polyester resin, polyimide resin Resin, fluorine resin, and the like.

The polyurethane resin used as the resin constituting the surface layer is a reaction product of a polyfunctional isocyanate compound and ethylene oxide polyol or polyester polyol. This polyurethane resin may have a hydrophilic functional group in the molecular chain, and it is preferable to use a polyurethane resin aqueous dispersion.

N-methoxymethylated nylon is preferable among the nylon resins that can be used as the resin constituting the resin layer. N-methoxymethylated nylon is 6
-It is obtained by methoxymethylating an amide group of nylon, and the solubility in alcohol is improved by increasing the methoxylation rate.

When a resin layer is used as the protective layer, the lower limit of the thickness of the resin layer is preferably 5 μm, more preferably 7 μm.
Particularly preferably, it is 10 μm, and the upper limit is preferably 200 μm, more preferably 150 μm, and particularly preferably 100 μm. If the layer thickness is too thin, the durability against abrasion may decrease, and if it is too thick, the coating may crack.

The roll of the present invention can be used for printers, copiers,
It can be used as a roll for OA equipment such as AX or for gravure printing. In particular, it is suitable for rolls used as electrophotographic OA equipment parts.

The roll used as the OA equipment component is a roll around the photoreceptor, and is particularly suitable as, for example, a charging roll, a developing roll, a transfer roll, and an intermediate transfer material.

[0064]

The present invention will be described more specifically with reference to examples and comparative examples. All solvents, monomers and the like used were those subjected to degassing and dehydration treatment. The methods for evaluating the properties of the rubber, the crosslinkable rubber composition, the crosslinked product, and the rubber roll are as follows.

(1) Mooney viscosity of rubber (ML _{1 + 4} , 1
00 ° C.) was measured according to JIS K6300. (2) The extrusion processability of the crosslinkable rubber composition is determined according to ASTM D
The measurement was performed according to ASTM-A.
According to the method, evaluation was made in four steps. The larger the number, the smaller the swell, the better the smoothness of the surface skin, and the better the extrudability. (3) The hardness of the crosslinked product was measured according to JIS K6253. (4) The compression set of the crosslinked product is determined according to JIS K6262.
It measured according to. The compression condition is 70 ° C. for 22 hours,
The compression ratio was 25%. (5) The bleed resistance of the crosslinked product was determined by observing the surface of the rubber sheet after leaving the rubber sheet for 1 week in an environment of 40 ° C. and 80% RH. Evaluation is × when bleeding occurs,
In case of no occurrence, it was marked as “○”. (6) The volume resistivity of the crosslinked product was prepared by press molding at 155 ° C. for 30 minutes to form a crosslinked rubber sheet having a thickness of 2 mm. 20% RH at 10 ° C. at voltage, 23
The measurement was performed under three conditions of 50% RH at 35 ° C., 35 ° C., and 80% RH. (7) The surface roughness of the rubber roll is JIS B0601
It measured according to. (8) The surface friction coefficient of the rubber roll was measured with a surface property measuring device HEIDON-14D manufactured by Shinto Kagaku Co., Ltd. (9) The electrical resistance of the roll is determined by measuring the distance between the shaft of the rubber roll and the electrode in a state in which a 1000-g column-shaped electrode made of brass having the same length as the rubber coating portion is brought into contact with the electrode so that its own weight is directly applied to the rubber roll. The DC voltage was adjusted to 500 V, and the electric resistance between the roll surface and the shaft was measured.

Reference Example 1 A sealed pressure-resistant glass bottle having an internal volume of 800 ml was replaced with nitrogen, and 180 g of toluene and 60 g of triisobutylaluminum were charged. After cooling the glass bottle by immersing it in ice water, 224.2 g of diethyl ether was added and stirred. Next, phosphoric acid 8. while cooling with ice water.
89 g was added and further stirred. At this time, the pressure in the bottle was increased due to the reaction between triisobutylaluminum and phosphoric acid. Next, formate of 1,8-diaza-bicyclo (5,4,0) undecene-7.
98 g were added. The resulting reaction mixture was aged for 1 hour in a 60 ° C. hot water bath to obtain a catalyst solution.

Reference Example 2 Epichlorohydrin 27 was added to a 5-liter autoclave.
0.1 g, 37.0 g of allyl glycidyl ether, 19.1 g of ethylene oxide and 3162.7 g of toluene were added, and the temperature of the inner solution was increased to 70 ° C. while stirring under a nitrogen atmosphere, and the catalyst solution obtained in Reference Example 1 was washed. The reaction was started by adding 13 ml.

Next, from the start of the reaction, ethylene oxide 1
A solution obtained by dissolving 23.8 g in 288.9 g of toluene was added to 5
It was added continuously at a constant rate over time. At the same time, the catalyst solution was added every 30 minutes in 7 milliliter portions over 5 hours.

The reaction was terminated by adding 15 g of water and stirring, and 4,4′-thiobis- was added as an antioxidant.
45 g of a 5% by weight (6-tert-butyl-3-methylphenol) toluene solution was added thereto, followed by stirring. After performing steam stripping and removing the supernatant water, vacuum drying was performed at 60 ° C. to obtain 440.1 g of epichlorohydrin rubber A having a Mooney viscosity of 65. Epichlorohydrin rubber A is a terpolymer containing 45 mol% of epichlorohydrin units, 5 mol% of allyl glycidyl ether units and 50 mol% of ethylene oxide units,
Confirmed by 1 H-NMR analysis.

Reference Example 3 The amount of epichlorohydrin was 411.0 g, the amount of allyl glycidyl ether was 28.1 g, the amount of ethylene oxide was 1.6 g, the amount of toluene was 3450.0 g, and the temperature was raised to 60 ° C. under a nitrogen atmosphere. The amount of the catalyst solution obtained in Reference Example 1 was 1
To 0 ml, the same treatment as in Reference Example 2 was carried out except that the toluene solution of ethylene oxide was changed to a solution in which 9.3 g of ethylene oxide was dissolved in 21.7 g of toluene, and had a Mooney viscosity of 80, epichlorohydrin unit of 90 mol%, and allyl glycidyl. 432.2 g of epichlorohydrin rubber B containing 5 mol% of ether units and 5 mol% of ethylene oxide units was obtained.

Reference Example 4 (Production of ethylene oxide-based ring-opening copolymer rubber 1) An autoclave with a stirrer having a content of 3 liters was dried and purged with nitrogen, and triisobutylaluminum 158.7 was obtained.
g, toluene 1170 g, and diethyl ether 29
6.4 g were charged. The internal temperature was set to 30 ° C., and 23.5 g of phosphoric acid was added at a constant rate over 10 minutes while stirring. To this, 12.1 g of triethylamine was added, and 6
An aging reaction was performed at 0 ° C. for 2 hours to obtain a catalyst solution.

A 5-liter autoclave with a stirrer was dried and purged with nitrogen, and 2100 g of n-hexane and 73.1 g of the above catalyst solution were charged. With the internal temperature set at 30 ° C., 4 g of ethylene oxide was added and reacted while stirring, and then 8.5 g of an equal weight mixed monomer of ethylene oxide and propylene oxide was added and reacted to form a seed.

The internal temperature was set to 60 ° C., and 340 g (90 mol%) of ethylene oxide, 14.9 g (3 mol%) of propylene oxide, 68.4 g (7 mol) of allyl glycidyl ether were added to the polymerization reaction solution in which the seed was formed. %), N-
A mixed solution consisting of 300 g of hexane was continuously added at a constant rate over 5 hours. After completion of the addition, the reaction was performed for 2 hours. The polymerization reaction rate was 98%. The obtained polymer was in a clean slurry state, the inner wall of the autoclave and the stirring blade were very clean, and no adhesion of the copolymer was observed. 42.4 g of a 5% by weight toluene solution of 4,4′-thiobis (6-tert-butyl-3-methylphenol) as an antioxidant was added to the obtained slurry.
, And the mixture was stirred, filtered through a wire mesh, dried at 40 ° C. in vacuo,
A powdery polymer sample was obtained.

Composition of ethylene oxide ring-opening copolymer rubber 1 thus obtained (content of each monomer unit)
Was 89.5 mol% of ethylene oxide, 3.7 mol% of propylene oxide, and 6.8 mol% of allyl glycidyl ether. Also, the Mooney viscosity (ML) of this polymer
_{1 + 4} , 100 ° C.) was 105.2.

Table 1 shows the composition ratio and the like of the ring-opening polymer rubber of the oxirane monomer used in the following Examples and Comparative Examples.

[0076]

[Table 1]

Examples 1 to 3 and Comparative Examples 1 to 3 Rubbers, fillers, crosslinking agents and the like having the compositions shown in Table 1 were kneaded with a roll to obtain a crosslinking rubber composition. Comparative Example 1
The ethylene oxide homocyclic ring-opening polymer used in the above was a commercially available product (PEO-8, manufactured by Sumitomo Seika Co., Ltd., Mooney viscosity (ML _{1 + 4} ,
100 ° C.) 70), and the silica has a pH of 10.4 to 1
0.9 and a BET adsorption surface area of 150 m ² / g (Carplex # 1120, manufactured by Shionogi Pharmaceutical Co., Ltd.) were used.

[0078]

[Table 2]

The crosslinkable rubber composition was evaluated for extrudability using an extruder having a diameter of 20 mm, and the results are shown in Table 1. This crosslinkable rubber composition was formed into a sheet and crosslinked at 155 ° C. for 30 minutes to obtain a crosslinked rubber sheet having a thickness of 2 mm. Table 3 shows the hardness and volume resistivity of each of the obtained crosslinked rubber sheets.

For forming the roll, the whole length is 263 mm made of stainless steel, and the length of the semiconductive layer coating portion is 227 m.
m, a cylindrical solid body having an outer diameter of 10 mm was used as a shaft body. The shaft and the rubber composition were simultaneously extruded using a crosshead extruder, and the periphery of the shaft was covered with the rubber composition. Crosslinking was carried out at 150 ° C. for 60 minutes using a steam can, and excess crosslinked rubber at both ends was removed to obtain a rubber roll.
The obtained rubber roll is polished on its surface with an abrasive,
A rubber roll having an outer diameter of 18 mm was obtained, and the roll electrical resistance and the like were measured. Table 3 shows the measurement results.

[0081]

[Table 3]

Ethylene oxide ring-opening copolymer rubber (2)
The rubber composition of Comparative Example 1 using a ring-opening polymer of ethylene oxide alone instead of is excellent in extrudability, but has a large compression set of the crosslinked product, produces bloom, and has a volume resistivity value due to environmental change. Fluctuation is large.

Epihalohydrin ring-opening copolymer rubber (1)
Is too small, and the mixed amount of the ethylene oxide-based ring-opening copolymer rubber (2) is too large. The crosslinked product of the rubber composition of Comparative Example 2 has a large compression set and changes in the volume resistivity due to environmental changes. The width is also large.

Epihalohydrin ring-opening copolymer rubber (1)
The rubber composition of Comparative Example 3 using only the ethylene oxide-based ring-opening copolymer rubber (2) did not have good extrudability, did not provide a smooth surface, and the crosslinked product was rolled. In the molding, the surface roughness after polishing was large, the surface friction coefficient was high, and the surface was slightly tacky.

On the other hand, the rubber compositions of the examples have good extrudability, and particularly excellent smoothness of swell and surface skin. The volume resistivity of the crosslinked product also shows an appropriate resistance, and the range of resistance fluctuation due to environmental changes is small. It also has good compression set and excellent bleed resistance. Also in roll forming, a smooth roll surface having a small surface roughness after polishing, a small surface friction coefficient and low tackiness can be obtained.

[0086]

Industrial Applicability The rubber composition of the present invention has good extrusion processability, and is particularly excellent in smoothness of swell and surface skin. The volume resistivity of the crosslinked product also shows an appropriate resistance, and the range of resistance fluctuation due to environmental changes is small. It also has good compression set and excellent bleed resistance. Also in roll forming, a crosslinked product which is suitable for use as a roll having a smooth surface with little surface roughness after polishing, a small surface friction coefficient and little tackiness can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F070 AA52 AB04 AB11 AB16 AC20 AC56 AC57 AE08 BA02 GA05 GA06 4J002 CH02X CH04W DA046 EK006 EV046 EV126 EV166 FD146 GM00 GM01 GQ00

Claims (3)

[Claims] 1. An epihalohydrin monomer (a) unit 35
~ 100 mol% and alkylene oxide monomer (b)
Epihalohydrin ring-opening copolymer rubber (1) containing 0 to 65 mol% of units and ethylene oxide (c) units 70 to
Ethylene oxide ring-opening containing 99 mol% and 30 to 1 mol% of oxirane monomer (d) units other than ethylene oxide, having a crosslinkable oxirane monomer unit content of 15 mol% or less and a Mooney viscosity of 20 to 200 And an epihalohydrin ring-opening copolymer rubber (1) based on the total weight of the epihalohydrin ring-opening copolymer rubber (1) and the ethylene oxide-based ring-opening copolymer rubber (2). Is 40 to 95% by weight. 2. A crosslinkable rubber composition comprising the rubber composition according to claim 1 and a crosslinking agent. 3. A crosslinked product obtained by crosslinking the crosslinkable rubber composition according to claim 2.