JP2007031572A - Elastomer composition and rubber roller using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastomer composition which can control the migration of a paraffinic oil in an elastomer to prevent the bleeding of the paraffinic oil, and to provide a rubber roller which can prevent a trouble that a contacted portion is decolored (whitened) and has low hardness and excellent abrasion resistance. <P>SOLUTION: This elastomer composition is characterized by comprising 100 pts.mass of a rubber component comprising at least one of dienic rubbers or EPDM rubbers, 2 to 150 pts.mass of a mixture of a thermoplastic elastomer with a thermoplastic resin, 50 to 250 pts.mass of a paraffinic oil, aluminum 2-ethylhexanoate in an amount of 0.1 to 50 mass% based on the paraffinic oil, a fatty acid in an amount of ≥0.1 mass%, and a cross-linking agent, wherein the rubber component is dispersed in the mixture of the thermoplastic elastomer with the thermoplastic resin. A rubber roller using the elastomer composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an elastomer composition and a rubber roller produced from the elastomer composition, and more particularly to a rubber roller suitably used as a paper feed roller, which suppresses bleeding of a paraffinic oil as a softening agent to reduce the color of a printing surface. The present invention relates to a rubber roller capable of preventing the occurrence of slipping and an elastomer composition as a raw material thereof.

  A rubber roller is used for a paper feeding mechanism in an ink jet printer, a laser printer, an electrostatic copying machine, a plain paper facsimile machine, an automatic deposit payment machine (ATM), and the like. Since this rubber roller needs to pick up a conveyed object such as paper or film and feed it while separating it, it is required to have excellent flexibility and high wear resistance. In addition, when using glossy paper with a small surface roughness of the printing paper at the time of high-quality printing such as photographic image quality, color loss (whiteout) may occur in the portion that contacts the rubber roller during paper feeding, It has been a problem in the past. This is because the softening agent that slightly bleeds from the paper feed rubber roller adheres to the printing paper, and as a result, the ink is repelled in the part that contacts the rubber roller during printing, and the color of the softening agent is higher than the part that the roller does not contact. This is thought to be due to poor riding.

  In order to prevent color loss (white spots), it is considered to reduce the amount of oil blended as a softening agent as much as possible, or to make a paper feed rubber roller using a composition that can be reduced in hardness without adding oil. ing.

Japanese Patent Application Laid-Open No. 2002-69244 (Patent Document 1) describes a thermoplastic elastomer composition in which the acetone extraction percentage is set to 0% or more and 20% or less, and a rubber roller made of the composition.
However, as described above, the paper feed rubber roller is required to have high wear resistance. When the rubber roller is used as the paper feed rubber roller, there is room for further improving the durability.

JP 2002-69244 A

  The present invention can prevent the bleeding of paraffinic oil by suppressing the migration of paraffinic oil in the elastomer, and the inconvenience that color loss (whiteout) occurs in the contacted portion. It is an object of the present invention to provide a rubber roller that can be manufactured and has low hardness and excellent wear resistance.

In order to solve the above problems, the present invention provides 2-150 parts by mass of a mixture of a thermoplastic elastomer and a thermoplastic resin with respect to 100 parts by mass of a rubber component containing at least one of diene rubber or ethylene-propylene-diene rubber. 50 to 250 parts by mass of paraffinic oil, 0.1 to 50% by mass of aluminum 2-ethylhexanoate, 0.1% by mass or more of fatty acid, and a crosslinking agent with respect to the paraffinic oil,
An elastomer composition is provided in which a rubber component is dispersed in a mixture of a thermoplastic elastomer and a thermoplastic resin by dynamic crosslinking.

  The present inventor has accumulated research on the bleed of the softening agent, paying attention to the migration of the softening agent in the elastomer, and intensively studied to suppress the migration of the softening agent. As a result, when paraffinic oil is used as a softening agent, the oil is gelled by blending a predetermined amount of aluminum 2-ethylhexanoate and fatty acid together with the paraffinic oil, thereby suppressing oil migration, and consequently oil bleeding. It was found that this can be prevented. Furthermore, the present inventor repeatedly studied other components of the elastomer composition and completed the present invention.

The elastomer composition of the present invention contains at least one of diene rubber or EPDM rubber as a rubber component.
Examples of the diene rubber used in the present invention include natural rubber (NR), butyl rubber (IIR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), and acrylonitrile. Examples thereof include butadiene rubber (NBR) and 1,2-polybutadiene. These may be used alone or in combination of two or more.
Examples of the diene monomer in the EPDM rubber include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, and cyclooctadiene. Any type can be used in the present invention.

  Rubbers other than diene rubber or EPDM rubber may be included as a rubber component. Examples of the “other rubber” include ethylene propylene rubber, acrylic rubber, and chlorosulfonated polyethylene.

  The elastomer composition of the present invention preferably contains EPDM rubber as a rubber component. The proportion of the EPDM rubber in the total rubber component is preferably 50% by mass or more, more preferably 80% by mass or more, and further preferably 95 to 100% by mass. This is because EPDM rubber is composed of saturated hydrocarbons in the main chain and does not contain double bonds in the main chain. Therefore, even when exposed to a high-concentration ozone atmosphere or an environment such as light irradiation for a long time, the main chain is broken. This is because the weather resistance of the final product, for example, a rubber roller can be improved.

  As described above, the elastomer composition of the present invention includes a mixture of a thermoplastic elastomer and a thermoplastic resin. The mixture of the thermoplastic elastomer and the thermoplastic resin is desirably an elastomer even after mixing. The reason is that the hardness of the elastomer composition finally obtained by dispersing the rubber component becomes lower.

  As the thermoplastic elastomer, a known thermoplastic elastomer can be used. Specifically, for example, styrene elastomer, chlorinated polyethylene, vinyl chloride elastomer, olefin elastomer, urethane elastomer, ester elastomer, amide elastomer, ionomer, ethylene ethyl acrylate resin (EEA), ethylene vinyl acetate copolymer Examples include coalescence (EVA).

  Of the thermoplastic elastomers, styrene elastomers are preferably used. As the styrene-based elastomer, a block copolymer of a polymer block (A) mainly composed of a styrene-based monomer and a block (B) mainly composed of a conjugated diene compound and a conjugated diene polymer unit of the block copolymer are hydrogenated. Can be illustrated. Examples of the styrenic monomer include styrene, α-methyl styrene, vinyl toluene, and t-butyl styrene. These monomers may be used alone or in combination of two or more. Of these, styrene is preferable as the styrene monomer. Examples of the conjugated diene compound include butadiene, isoprene, chloroprene, and 2,3-dimethylbutadiene. These may be used alone or in combination of two or more.

  Specific examples of the styrene elastomer include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene / butylene-styrene copolymer (SEBS), styrene- Examples include ethylene / propylene-styrene copolymer (SEPS) or styrene-ethylene-ethylene / propylene-styrene copolymer (SEEPS). Among them, styrene-ethylene-ethylene / propylene-styrene copolymer (SEEPS) is used. It is preferable to use it.

  A well-known thing can be used as said thermoplastic resin, For example, an olefin resin, a polystyrene (PS), a polyethylene terephthalate (PET), a polybutylene terephthalate (PBT), nylon etc. are mentioned. Among these, it is preferable to use an olefin resin. Examples of the olefin resin include polyethylene, polypropylene, ethylene ethyl acrylate resin, ethylene vinyl acetate resin, ethylene-methacrylic acid resin, or ionomer resin, but polypropylene or polyethylene is preferable, and polypropylene is more preferable. .

The mixture of the thermoplastic elastomer and the thermoplastic resin is preferably included at a ratio of 2 to 150 parts by mass with respect to 100 parts by mass of the rubber component.
When the blending amount of the mixture is less than 2 parts by mass, the resin component becomes too small to disperse the rubber component in the resin matrix, making it difficult to process and lowering the strength and wear resistance of the molded product. On the other hand, when the blending amount of the mixture exceeds 150 parts by mass, the resin component becomes too much and the hardness becomes high. As a result, when a rubber roller made of the composition is used as a paper feed rubber roller, there may be a problem that the coefficient of friction with respect to the paper decreases and the wear resistance also decreases.

  The mixing ratio of the thermoplastic elastomer and the thermoplastic resin in the mixture can be determined as an appropriate mixing ratio depending on the elastomer and the resin used, but the thermoplastic resin is 1 part by mass or more with respect to 100 parts by mass of the thermoplastic elastomer. The amount is preferably 100 parts by mass or less. This is because if the mixing amount of the thermoplastic resin is less than 1 part by mass, the effect of mixing the thermoplastic resin is not seen, and if the mixing amount of the thermoplastic resin is more than 100 parts by mass, the mixture is not an elastomer. . The mixing amount of the thermoplastic resin is more preferably 20 to 80 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer.

  Moreover, the elastomer composition of this invention contains 50-250 mass parts of paraffinic oil with respect to 100 mass parts of rubber components as mentioned above. When the blending amount of the paraffinic oil is less than 50 parts by mass, it becomes difficult to process and it is difficult to achieve low hardness when molded into a rubber roller. On the other hand, when the blending amount of the paraffinic oil exceeds 250 parts by mass, there may be a problem that strength and wear resistance are reduced when the rubber roller is molded.

The paraffinic oil used in the present invention preferably contains no aroma. Including a small amount of aroma may contaminate the paper.
Examples of the paraffinic oil include paraffinic compounds having 4 to 155 carbon atoms, preferably paraffinic compounds having 4 to 50 carbon atoms, specifically, butane, pentane, hexane, heptane, octane, nonane, Decane, Undecane, Dodecane, Tetradecane, Pentadecane, Hexadecane, Heptadecane, Octadecane, Nonadecane, Eicosan, Henicosan, Docosan, Tricosan, Tetracosan, Pentacosan, Hexacosan, Heptacosan, Octacosan, Nonacosan, Triacontan, Hentriacontan, Dotria Contan, Penta N-paraffins (linear saturated hydrocarbons) such as triacontane, hexacontane or heptacontane; isobutane, isopentane, neopentane, isohexane, isopentane, ne Hexane, 2,3-dimethylbutane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethyl Pentane, 2,2,3-trimethylbutane, 3-methylheptane, 2,2-dimethylhexane, 2,3-dimethylhexane, 2,4-dimethylhexane, 2,5-dimethylhexane, 3,4-dimethylhexane 2,2,3-trimethylpentane, isooctane, 2,3,4-trimethylpentane, 2,3,3-trimethylpentane, 2,3,4-trimethylpentane, isononane, 2-methylnonane, isodecane, isoundecane, Isododecane, isotridecane, isotetradecane, isopentadecane, isooctadecane, Nanodekan, isoeicosane or 4-ethyl-5-isoparaffins methyl octane (branched saturated hydrocarbons); or, may be mentioned derivatives of these saturated hydrocarbons. These paraffins are used in a mixture and are preferably liquid at room temperature.

  Commercially available paraffinic oils that are liquid at room temperature include NA Solvent (isoparaffinic hydrocarbon oil) manufactured by Nippon Oil & Fats, PW-380 (n-paraffinic process oil) manufactured by Idemitsu Kosan Co., Ltd. IP-solvent 2835 (synthetic isoparaffinic hydrocarbon, 99.8% by mass or more isoparaffin) manufactured by Idemitsu Petrochemical Co., Ltd., neothiozole (n-paraffinic process oil) manufactured by Sanko Chemical Industry Co., Ltd. .

  Moreover, a small amount of unsaturated hydrocarbons and derivatives thereof may coexist in the paraffinic oil. Unsaturated hydrocarbons include ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 3-methyl-1-butene, 3-methyl-2-butene, 2-methyl-2 -Ethylene hydrocarbon such as butene, 1-hexene, 2,3-dimethyl-2-butene, 1-heptene, 1-octene, 1-nonene or 1-decene; or acetylene, methylacetylene, 1-butyne, Examples thereof include acetylene hydrocarbons such as 2-butyne, 1-pentyne, 1-hexyne, 1-octyne, 1-nonine and 1-decyne.

The paraffinic oil preferably used in the present invention has a% CP in ring analysis of 50 or more, more preferably 60 to 80, a total acid value of 0.05 (mg KOH / g) or less, more preferably 0.01 or less, aniline. The point is 100 to 160 ° C., more preferably 120 to 150 ° C., and the kinematic viscosity at 40 ° C. is 150 to 1000 centistokes, more preferably 200 to 500 centistokes. For example, the paraffinic oil used in the examples of the present invention has a% CP of 73 in the ring analysis, a total acid value of 0.01 (mg KOH / g) or less, an aniline point of 144 ° C., a sulfur content of 6 ppm, and 40 ° C. The kinematic viscosity is 382 centistokes.
The value of the aniline point is JIS
The value measured by the test tube method prescribed | regulated to K2256 is shown, and the value of a sulfur content shows the value measured by the microcoulometric titration oxidation method prescribed | regulated to JISK2541.

In the present invention, a part of the paraffinic oil may be replaced with another petroleum softener or plasticizer. In this case, the amount of paraffinic oil that can be replaced with other petroleum softeners or plasticizers is more than 0 and not more than 30% by mass, preferably more than 0 and not more than 10% by mass with respect to the entire paraffinic oil. It is.
Examples of the petroleum softener include known synthetic oils or process oils made of naphthenic mineral oils or hydrocarbon oligomers. Examples of the plasticizer include phthalate-based, adipate-based, sebacate-based, phosphate-based, polyether-based, and polyester-based plasticizers.

The elastomer composition of the present invention contains 0.1 to 50% by mass of aluminum 2-ethylhexanoate and 0.1% by mass or more of fatty acid with respect to paraffinic oil. When the proportion of aluminum 2-ethylhexanoate is less than 0.1% by mass or when the proportion of fatty acid is less than 0.1% by mass, the gelation of the oil becomes insufficient, and therefore oil transfer is suppressed. The effect is reduced, and as a result, the effect of suppressing bleeding is insufficient.
On the other hand, when the proportion of aluminum 2-ethylhexanoate exceeds 50% by mass, the gelling is advanced too much, and the elastomer composition becomes hard and it becomes difficult to realize low hardness when molded into a rubber roller. It is not practical because of the high cost. The upper limit of the amount of the fatty acid is not particularly limited, but is usually 100% by mass or less, preferably 50% by mass or less.

Especially, it is preferable that the compounding quantity of 2-ethyl hexanoic acid aluminum is 0.1-30 mass% with respect to paraffinic oil, and it is more preferable that it is 0.5-20 mass%. The blending amount of the fatty acid is preferably 0.1 to 10% by mass and more preferably 0.1 to 5% by mass with respect to the paraffinic oil.
The mass ratio of the amount of aluminum 2-ethylhexanoate and the amount of fatty acid is preferably (2-ethylhexanoic acid aluminum) :( fatty acid) = 10 to 1: 1, preferably 6 to 1: 1. It is more preferable.

Examples of the fatty acid used in the present invention include saturated fatty acids or unsaturated fatty acids having 8 to 24 carbon atoms. Specifically, examples of the fatty acid include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, behenic acid, undecylenic acid, oleic acid, linoleic acid, and linolenic acid. These may be used alone or in combination of two or more. Of these, stearic acid is preferably used in the present invention.
The fatty acid used in the present invention may be a fatty acid salt or derivative. Examples of fatty acid salts include salts with alkali metals such as sodium, potassium and lithium, and salts with alkaline earth metals such as barium, calcium, magnesium and zinc. Examples of fatty acid derivatives include hydroxyl acid.

  The elastomer composition of the present invention contains a crosslinking agent. The blending amount of the cross-linking agent may be appropriately selected depending on the type of the cross-linking agent, and is preferably, for example, 1 part by mass or more and 20 parts by mass or less, and 8 parts by mass or more and 15 parts by mass with respect to 100 parts by mass of the rubber component. The following is particularly preferable. If the amount of the crosslinking agent is less than 1 part by mass, insufficient crosslinking may occur and the durability of the molded product may be lowered. On the other hand, if the amount of the crosslinking agent exceeds 20 parts by mass, excessive crosslinking may occur and thermal deterioration may occur due to abnormal heat generation during dynamic crosslinking.

As the crosslinking agent, for example, a known crosslinking agent such as a resin crosslinking agent or a peroxide crosslinking agent can be used, but a resin crosslinking agent is preferably used.
The resin cross-linking agent is a synthetic resin that causes a cross-linking reaction to rubber by heating or the like, and examples thereof include phenol resin, melamine / formaldehyde resin, triazine / formaldehyde condensate, hexamethoxymethyl / melamine resin, and the like. Among these, it is preferable to use a phenol resin.

Specific examples of the phenol resin include various phenol resins synthesized by reaction of phenols such as phenol, alkylphenol, cresol, xylenol or resorcin with aldehydes such as formaldehyde, acetaldehyde or furfural. A halogenated phenol resin in which at least one halogen atom is bonded to the aldehyde unit of the phenol resin can also be used.
In particular, alkylphenol-formaldehyde resins obtained by the reaction of formaldehyde with alkylphenols having an alkyl group bonded to the ortho or para position of benzene are excellent in compatibility with rubber and have a high reactivity so that the crosslinking reaction start time is increased. This is preferable because it can be done relatively quickly. The alkyl group of the alkylphenol / formaldehyde resin is usually an alkyl group having 1 to 10 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group. Moreover, the halide of this alkylphenol formaldehyde resin is also used suitably.
Furthermore, a modified alkylphenol resin obtained by addition condensation of sulfurized p-tert-butylphenol and aldehydes, or an alkylphenol sulfide resin can also be used as a resin crosslinking agent.

In order to appropriately perform the crosslinking reaction, a crosslinking assistant (activator) may be used. As the crosslinking aid, a metal oxide is used, and zinc oxide and zinc carbonate are particularly preferable.
The blending amount of the crosslinking aid may be appropriately selected according to the type and the type of the crosslinking agent. For example, the amount is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, the amount is 10 parts by mass or more.

In the elastomer composition of this invention, a filler can be mix | blended as needed. Examples of the filler include powders such as silica, carbon black, clay, talc, calcium carbonate, dibasic phosphite (DLP), basic magnesium carbonate, and alumina. When blending a filler, the filler is preferably blended at 15% by mass or less of the total mass of the elastomer composition. This is because the blending of the filler is effective in improving the tensile strength and tear strength of the elastomer composition, but if too much is blended, the flexibility of the elastomer composition is reduced and the friction coefficient of the roller is reduced. This is to show a tendency to decrease.
In the elastomer composition of the present invention, in addition to the above components, an anti-aging agent, an antioxidant, an ultraviolet absorber, a lubricant, a pigment, an antistatic agent, a flame retardant, and a neutralizing agent, unless the object of the present invention is contrary. In addition, additives such as a nucleating agent or an anti-bubble agent may be appropriately blended.

Polymer component excluding non-polymer components such as paraffinic oil, aluminum 2-ethylhexanoate, fatty acid and filler (rubber component + thermoplastic elastomer + thermoplastic resin + resin cross-linking agent + others) The ratio of the additive resin) is preferably 40% by mass or more and 95% by mass or less, and more preferably 59% by mass or more and 95% by mass or less.
The reason why it is 40% by mass or more is to ensure the wear resistance of the elastomer composition, and the reason why it is 95% by mass or less is to ensure the kneadability and moldability of the elastomer composition.

In the elastomer composition of the present invention, the rubber component is dynamically cross-linked, and the rubber component is dispersed in a mixture of the thermoplastic elastomer and the thermoplastic resin.
The dynamic crosslinking in the present invention may be performed in the presence of a halogen such as chlorine, bromine, fluorine or iodine. In order to allow halogen to be present during dynamic crosslinking, the halogenated resin crosslinking agent described above may be used, or a halogen-donating substance may be blended in the elastomer composition. Examples of the halogen donating substance include tin chloride such as stannic chloride, ferric chloride, and cupric chloride. One kind of halogen-donating substance may be used alone, or two or more kinds may be used in combination.

The elastomer composition of the present invention can be produced, for example, as follows.
Kneading the rubber component, a mixture of thermoplastic elastomer and thermoplastic resin, paraffinic oil, aluminum 2-ethylhexanoate, fatty acid, cross-linking agent, and other additives as required using a Henschel mixer, super mixer or tumbler type mixer Put into the machine and knead. This kneaded product is put into a single-screw or twin-screw extruder or a kneader, and the rubber component is dynamically cross-linked by a cross-linking agent while being heated to 150 to 250 ° C., and the rubber component is put into the mixture of the thermoplastic elastomer and the thermoplastic resin. Disperse.

  The elastomer composition of the present invention described above can be used for various applications. Among them, it is preferable to use as a member that contributes to paper conveyance in an OA device such as a copying machine, a printer, a facsimile, or an ATM. More specifically, the present invention can be applied to separation sheets, separation pads, and paper feed rollers for preventing paper double feeding. In particular, it is particularly preferable to apply to a paper feed roller such as a paper feed roller, a transport roller, or a paper discharge roller constituting the paper feed mechanism.

The present invention provides a rubber roller formed using the elastomer composition. The rubber roller may have any structure as long as it has at least a layer made of the elastomer composition of the present invention on the surface layer. However, a rubber roller having only a layer made of the elastomer composition of the present invention is preferable in view of manufacturing process management and cost because of its simple structure. The rubber roller of the present invention is usually used in a state of being inserted around a metal core made of metal, ceramics or the like.
The thickness of the rubber roller of the present invention is preferably 1 to 20 mm, and more preferably 2 to 20 mm. This is because if the thickness is less than 1 mm, the elasticity is insufficient and the conveyance performance tends to be lowered, and if the thickness exceeds 20 mm, the rubber roller becomes too large to be easily mounted on a copying machine or a printer.

  The rubber roller of the present invention has a hardness measured according to JIS K6253 set to 30 or more and 50 or less. The reason why the hardness is 30 or more and 50 or less is that the rubber roller having a hardness in this range shows good flexibility, and even if the rubber roller is pressed against the paper or film with a relatively small pressure, the rubber roller is sufficiently deformed, This is because a large contact area with the film can be obtained. If the hardness is less than 30, there is a problem that the amount of wear increases, and if the hardness exceeds 50, there is a problem that non-feed occurs during the sheet passing. The hardness of the rubber roller of the present invention is more preferably 35 or more and 45 or less.

The rubber roller of the present invention can be manufactured, for example, as follows.
The elastomer composition of the present invention may be extruded from a twin-screw extruder to be pelletized, the pellet may be extruded into a tube shape by an extruder, and may be cut into a rubber roller, or the pellet may be injected by an injection (injection) molding machine. After injection and forming into a tube shape, and polishing the surface of the molded product, it may be cut into a required dimension to form a rubber roller.

  In the elastomer composition of the present invention, by blending aluminum 2-ethylhexanoate and a fatty acid, the paraffinic oil that is a softening agent gels, so that the migration of the paraffinic oil in the elastomer is suppressed. As a result, in the rubber roller made of the elastomer composition of the present invention, paraffinic oil as a softening agent does not bleed from the surface. Therefore, for example, when the rubber roller of the present invention is used as a paper feed roller, color loss (whiteout) does not occur even in high-quality printing such as photographic image quality using super fine glossy paper, photo print paper or color OHP paper. .

  Furthermore, since the blending ratio of each component of the elastomer composition of the present invention is adjusted to a predetermined ratio, the rubber roller made of the elastomer composition has a high coefficient of friction and ensures wear resistance. . Further, the hardness of the rubber roller of the present invention is set to 30 or more and 50 or less, and when used as a paper feed roller in an OA device such as a copying machine or a printer, a large contact area is obtained between the paper and the film. It is possible to suppress the non-feeding during the paper feeding.

Hereinafter, embodiments of the present invention will be described.
The elastomer composition of the present invention contains EPDM rubber as a rubber component. Further, a mixture of a styrene thermoplastic elastomer as a thermoplastic elastomer and polypropylene as a thermoplastic resin is included. The mixture of the styrenic thermoplastic elastomer and polypropylene is blended in an amount of 30 to 100 parts by mass, preferably 50 to 90 parts by mass with respect to 100 parts by mass of the EPDM rubber. The mixing ratio of the styrenic thermoplastic elastomer and polypropylene in the mixture is 10 to 80 parts by mass, preferably 20 to 60 parts by mass with respect to 100 parts by mass of the styrene thermoplastic elastomer.

Furthermore, paraffinic process oil is included as paraffinic oil. The paraffinic process oil is blended in an amount of 100 to 250 parts by mass, preferably 150 to 250 parts by mass with respect to 100 parts by mass of the EPDM rubber.
In order to suppress bleeding of the paraffinic oil, aluminum 2-ethylhexanoate and a fatty acid are included. Stearic acid is used as the fatty acid. Aluminum 2-ethylhexanoate is blended in an amount of 1 to 20 parts by weight with respect to 100 parts by weight of EPDM rubber, and 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of paraffinic oil. Has been. Fatty acids are blended in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of EPDM rubber, and 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of paraffinic oil. . The mass ratio of the compounding quantity of 2-ethylhexanoic acid and the compounding quantity of fatty acid is (2-ethylhexanoic acid aluminum) :( fatty acid) = 10-1: 1, Preferably it is 6-1: 1.

Furthermore, a phenolic resin crosslinking agent is blended as a crosslinking agent. The phenolic resin crosslinking agent is blended in an amount of 1 to 20 parts by weight, preferably 8 to 15 parts by weight, based on 100 parts by weight of EPDM rubber.
Furthermore, zinc oxide is included as a crosslinking aid in order to appropriately perform the crosslinking reaction. Zinc oxide is blended in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of EPDM rubber.

  The above components are added to a tumbler type kneader at a required blending ratio and kneaded. The temperature during kneading is 150 to 300 ° C, preferably 200 to 250 ° C, and the kneading time is 1 to 60 minutes, preferably 5 to 30 minutes. The obtained kneaded material is put into a twin-screw extruder and dynamically crosslinked at 150 to 250 ° C., preferably 200 ° C., to uniformly disperse the rubber component, and to produce the elastomer composition of the present invention as pellets is doing.

This pellet is extruded into a tube shape using a single screw extruder under a condition of 190 to 230 ° C., and a metal core is pressed into the hollow portion, or both are bonded and fixed with an adhesive, and the present invention is fixed. Got rubber rollers.
A substantially D-shaped rubber roller can be obtained by press-fitting a substantially D-shaped core material into the hollow portion of the roller portion formed into a cylindrical shape. A knurled groove may be provided on the surface of the rubber roller of the present invention. The rubber roller of the present invention manufactured in the above process has a hardness measured in accordance with JIS K6253 of 30 to 50.

"Example"
An Example and a comparative example are shown and this invention is explained in full detail.
A rubber roller was produced using an elastomer composition having the composition shown in Table 1 below, and the hardness, occurrence of roller marks, wear resistance, and friction coefficient were evaluated by the methods described below for the obtained rubber roller. The evaluation results are shown in Table 1.

The following products were used for each component in the table.
・ EPDM rubber; "Esprene 505A" manufactured by Sumitomo Chemical Co., Ltd.
・ Thermoplastic elastomer: Styrenic thermoplastic elastomer (Kuraray Co., Ltd. “Septon 4077”)
・ Thermoplastic resin: Polypropylene ("Novatec PP" manufactured by Nippon Polypro Co., Ltd.)
Paraffinic oil; paraffinic process oil (“Diana Process Oil PW-380” manufactured by Idemitsu Kosan Co., Ltd.)
・ 2-ethylhexanoic acid aluminum; “Octopope Aluminum A” manufactured by Hope Pharmaceutical Co., Ltd.
・ Fatty acid; stearic acid (manufactured by NOF Corporation)
・ Crosslinking agent: Phenolic resin crosslinking agent (Takaki roll 250-III, manufactured by Taoka Chemical Co., Ltd.)
・ Crosslinking aid: Zinc oxide (“Zinc Hana 1” manufactured by Mitsui Kinzoku Mining Co., Ltd.)

A rubber roller was manufactured by the following process.
First, the materials were weighed, and the amount of EPDM rubber, thermoplastic elastomer, thermoplastic resin, paraffinic oil, aluminum 2-ethylhexanoate, fatty acid, crosslinking agent and crosslinking aid shown in Table 1 were blended, and the tumbler And mixed for 10 minutes. Thereafter, the EPDM rubber was dynamically cross-linked at 200 ° C. with a twin screw extruder (HTM38 manufactured by Ibeck Co., Ltd.) to produce an elastomer composition, which was extruded and pelletized.
Next, this pellet was extruded into a tube shape using a single screw extruder (manufactured by Kasamatsu Processing Laboratory Co., Ltd., φ50 extruder) under the conditions of 20 rpm and temperature control of 190 ° C. to 230 ° C., outer diameter 22 mm, inner diameter 18 mm. An extruded product was obtained. This tubular extruded product was cut into a 15 mm width, and a cored bar was inserted into the hollow portion and fixed to obtain a rubber roller.

The test method of a rubber roller is shown.
(hardness)
The measurement was performed at an ambient temperature of 23 ° C. in accordance with JIS K6253.
(Roller marks)
The surface of each rubber roller in Examples and Comparative Examples was wiped with alcohol and then left in an oven at 60 ° C. overnight. Each rubber roller after being left is mounted on an inkjet printer (“PM-770C” manufactured by Seiko Epson Corporation) as a feed roller, and OHP paper (Seiko Epson Corporation) under the conditions of a temperature of 23 ° C. and a relative humidity of 55%. Green halftone was printed on an OHP sheet for an inkjet printer.
At this time, the roller contact portion is visually checked for color loss. When there is no color loss, “◎”, when color loss is not noticeable, “○”, and when color loss is noticeable, “×” ".

(Abrasion resistance)
Each rubber roller of the example and the comparative example is attached to a copying machine as a paper feed roller, and A4 size paper (PPC paper manufactured by Fuji Xerox Office Supply Co., Ltd.) 20,000 under the conditions of a temperature of 23 ° C. and a relative humidity of 55%. The sheet was passed for 10 hours, and the amount of wear was determined by measuring the mass of the rubber roller before and after passing. Table 1 shows an index when the amount of wear in Comparative Example 1 is 100, and the larger the index, the better the wear resistance.

(Coefficient of friction)
The friction coefficient was evaluated using the apparatus shown in FIG. A4 size PPC paper 4 (Fuji Xerox Office Supply Co., Ltd.) connected to the load cell 5 is sandwiched between each rubber roller 1 and the plate 3 in the examples and comparative examples, and the core of the rubber roller 1 as shown by the black arrow. A load W of 250 gf was applied to the gold 2 and the rubber roller 1 was pressed against the plate 3. Then the temperature is 23 ° C
Under the condition of 55% relative humidity, the rubber roller 1 was rotated in the direction indicated by the arrow a at a peripheral speed of 300 mm / second, and the force F (gf) generated in the direction indicated by the white arrow was measured by the load cell 5. Then, the friction coefficient μ was obtained from the measured value F (gf) and the load W (W = 250 gf) by the following formula 1. Table 1 shows an index when the friction coefficient of Comparative Example 1 is set to 100. The larger the index, the higher the friction coefficient and the better the paper conveying force.
μ = F (gf) / W (gf) (Formula 1)

In Comparative Example 1 where aluminum 2-ethylhexanoate and fatty acid were not added, in Comparative Example 6 where the amount of aluminum 2-ethylhexanoate was small, and in Comparative Example 8 where the amount of fatty acid was slight, Since the paraffinic oil was not sufficiently gelled and bleeded, color loss occurred. On the other hand, in Comparative Example 7 in which the amount of aluminum 2-ethylhexanoate was large, the gelation of the paraffinic oil progressed too much, so that the hardness was high and the friction coefficient was low.
In Comparative Example 2 in which the blending amount of the mixture of the thermoplastic elastomer and the thermoplastic resin was small, the hardness of the rubber roller was extremely lowered and the wear resistance was also lowered. On the other hand, in Comparative Example 3 where the blending amount of the mixture was large, the hardness of the rubber roller was high, so both the wear resistance and the friction coefficient of the rubber roller were low.
In Comparative Example 4 in which the blending amount of the paraffinic oil is small, since the hardness is high and the friction coefficient is low, there is a possibility that paper non-feeding may occur when used as a paper feed roller. On the other hand, in Comparative Example 5 in which the blending amount of paraffinic oil was large, the wear resistance was lowered.

  On the other hand, the rubber roller of the example has an appropriate hardness of 40 to 50, a high coefficient of friction, and excellent wear resistance. Further, the migration of paraffinic oil as a softening agent was suppressed by aluminum 2-ethylhexanoate and fatty acid, and as a result, occurrence of color loss could be prevented without bleeding of paraffinic oil.

It is a schematic diagram of the apparatus for measuring a friction coefficient in an Example.

Explanation of symbols

1 Rubber roller 2 Core metal 3 Plate 4 PPC paper 5 Load cell

Claims (5)

2 to 150 parts by mass of a mixture of a thermoplastic elastomer and a thermoplastic resin, 50 to 250 parts by mass of paraffinic oil, paraffin with respect to 100 parts by mass of a rubber component containing at least one of diene rubber or ethylene-propylene-diene rubber 0.1 to 50% by mass of aluminum 2-ethylhexanoate, 0.1% by mass or more of fatty acid, and a crosslinking agent with respect to the system oil,
An elastomer composition comprising a rubber component dispersed in a mixture of a thermoplastic elastomer and a thermoplastic resin by dynamic crosslinking.   The elastomer composition according to claim 1, wherein the crosslinking agent is a phenolic resin crosslinking agent.   A rubber roller using the elastomer composition according to claim 1.   The rubber roller according to claim 3 whose hardness measured according to JIS K6253 is 30 or more and 50 or less.   The rubber roller according to claim 3 or 4 used as a paper feed roller of an image forming apparatus.

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