JP5366120B2 - Manufacturing method of rubber member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber member excellent in abrasion resistance and antifouling properties. <P>SOLUTION: By conducting the impregnation treatment wherein the operation is performed two or more times that infiltrates a treating solution containing an isocyanate compound and an organic solvent into at least one elastic body selected from fluoropolymers, silicone polymers and polyether polymers, there is manufactured the rubber member in which at least the density of the isocyanate compound is gradually lower from the surface of the elastic body toward its inside. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a rubber member. Such rubber members are used for paper feeding / conveying rolls for various paper feeding / conveying in various OA devices such as copiers, facsimiles, various printers, etc., charging rolls, transfer rolls, developing rolls, conductive rolls used in image forming apparatuses. It is particularly suitable for use in rolls and the like.

  The rolls for charging, transferring, developing, and feeding / conveying of various OA devices are required to have a low hardness so as not to damage a contact member such as a photoreceptor. Conventionally, EPDM rubber has been used for such rolls (see Patent Documents 1 and 2, etc.). However, as described in these documents, in order to reduce the hardness with solid rubber, it is necessary to add a large amount of a softening agent, and there are problems in terms of contamination due to bleeding and durability.

  On the other hand, a roll may be made low hardness using sponge, ie, a foam. Sponge rolls can be reduced in hardness relatively easily, can be reduced in weight, and are excellent in paper dust resistance. However, when the sponge roll is used for a long period of time, problems such as image failure (charging / transfer roll) and reduction in conveying force (feeding / conveying roll) may occur.

  In view of this, a structure in which various coating layers, surface treatment layers, or coated tubes are provided on the surfaces of various elastic layers has been proposed. The applicant of the present invention is a roll (see Patent Document 3) in which a surface treatment layer or a surface coat layer is provided on the surface of an elastic layer in which naphthenic oil is blended with epichlorohydrin rubber, or a surface containing at least a polyether polymer and an isocyanate compound. A rubber member (see Patent Document 4) surface-treated with a treatment liquid is proposed. These inventions are simple and effective. However, when the elastic body is a foam, in the conventional surface treatment, the treatment liquid is impregnated not only in the vicinity of the surface but also inside the foam, and the hardness is high. Sometimes it became.

  In addition, a toner supply roller in which an urethane compound layer is coated and impregnated with an isocyanate compound has been proposed (see Patent Document 5). This roller has low hardness and does not exude the unreacted polyol component on the roller surface. However, in a situation where the roller is pressed against the opposing member and used for a long time, satisfaction is obtained in terms of durability. It wasn't something you could do.

  Moreover, what is further excellent in stain resistance compared with the past is calculated | required.

JP-A-5-77508 Japanese Patent Application Laid-Open No. 7-242799 JP 2007-121724 A JP 2007-39678 A JP 2008-15008 A

  This invention makes it a subject to provide the manufacturing method of the rubber member excellent in stain resistance and durability in view of such a situation.

According to a first aspect of the present invention for solving the above-mentioned problems, a rubber composition containing a rubber base material is cured and formed by impregnating a treated liquid containing an isocyanate compound and an organic solvent into an elastic body so as to penetrate. When the resin is cured, the impregnation treatment is performed such that the permeation operation is performed twice or more so that the permeation depth of the treatment liquid gradually decreases in the thickness direction. In the method of manufacturing a rubber member, a rubber member that is gradually sparse is formed for each penetration depth of the permeation operation .

According to a second aspect of the present invention, in the method for producing a rubber member according to the first aspect, the impregnation treatment uses a treatment liquid in which at least one of an isocyanate compound and an organic solvent is different. It exists in the manufacturing method of a member.

According to a third aspect of the present invention, in the method for producing a rubber member according to the first or second aspect, the impregnation treatment uses treatment liquids having different isocyanate compound concentrations. It is in.

According to a fourth aspect of the present invention, in the method for producing a rubber member according to the third aspect, in the impregnation treatment, a treatment liquid having a low concentration of isocyanate compound is infiltrated in order from the treatment liquid. It is in.

According to a fifth aspect of the present invention, in the method for producing a rubber member according to any one of the first to fourth aspects, the treatment liquid is selected from a fluorine-based polymer, a silicone-based polymer, and a polyether-based polymer. The rubber member manufacturing method is characterized by containing at least one kind.

  According to the present invention, a rubber member excellent in contamination resistance and durability can be provided.

  In the method for producing a rubber member of the present invention, the density of at least the isocyanate compound is increased from the surface of the elastic body by an impregnation treatment in which an elastic body is infiltrated with a treatment liquid containing an isocyanate compound and an organic solvent twice or more. The rubber member which becomes sparse in steps toward is manufactured. The manufactured rubber member is excellent in wear resistance and contamination resistance while keeping the hardness low.

  Here, stepwise sparse refers to a state in which the amount of the component (mainly isocyanate compound) of the treatment liquid is gradually reduced toward the inside of the elastic body. Usually, for example, when a foamed elastic body is impregnated with a treatment liquid containing an isocyanate compound, the isocyanate compound is impregnated into the inside of the foamed elastic body, and a rubber member having a uniform density of the isocyanate compound from the surface to the inside of the foamed elastic body is obtained. Although formed, according to the present invention, it is possible to produce a rubber member in which the density of the isocyanate compound gradually decreases from the surface of the elastic body toward the inside. Since the foamed rubber member is formed so that the isocyanate compound becomes gradually sparse from the surface of the elastic body toward the inside, the rubber member can disperse the stress at a predetermined pressing load, and the followability It will be excellent.

  The impregnation treatment refers to a treatment in which a treatment liquid is infiltrated into an elastic body, an organic solvent is removed, and a component such as an isocyanate compound is cured. The isocyanate compound impregnated in the elastic body reacts with other isocyanate compounds, other components (fluorine-based polymers, etc.), the rubber substrate constituting the elastic body, etc., and these crosslinked structures are formed inside the elastic body. The Thereby, a rubber member having improved wear resistance is formed as compared with the elastic body before impregnation with the treatment liquid. In such a rubber member, when the treatment liquid is impregnated to the inside of the elastic body, there is a risk that unreacted components, conductivity imparting material, etc. inside the elastic body may elute to the surface when deformed at a predetermined pressure load. No contamination resistance.

  In the impregnation treatment in the present invention, the operation of allowing an elastic body to permeate a treatment liquid containing an isocyanate compound and an organic solvent is performed twice or more. At this time, the density of the isocyanate compound or the like in the treatment liquid is gradually decreased from the surface of the elastic body toward the inside. Examples of the method for allowing the treatment liquid to permeate the elastic body include a method for immersing (dipping) the elastic body in the treatment liquid, a method for spraying the treatment liquid onto the elastic body, and the like. The operation of allowing the treatment liquid to penetrate into the elastic body may be performed twice or more, and the number of times is not particularly limited. The operation of infiltrating the treatment liquid may be performed again after the treatment liquid is infiltrated and the isocyanate compound of the elastic body is cured. That is, the isocyanate compound or the like may be cured after the treatment liquid has been permeated twice or more, and the isocyanate compound or the like may be repeatedly cured after the treatment liquid has been permeated. In the case where the treatment liquid is infiltrated into the elastic body by dipping, it is preferable that the impregnation treatment is carried out by repeatedly curing the isocyanate compound or the like of the elastic body after impregnating the treatment liquid. This is because it is possible to prevent the isocyanate compound or the like that has penetrated into the elastic body from being dissolved into the treatment liquid used thereafter. Further, when the isocyanate compound or the like is cured after the treatment liquid has been infiltrated twice or more, the treatment liquid may be infiltrated twice or more and then left for a predetermined time to diffuse the treatment liquid and then be cured. By leaving it to stand for a predetermined time, the density of the isocyanate compound and the like can be gradually reduced.

  In the impregnation treatment, it is preferable that the penetration depth of the treatment liquid is gradually decreased in the thickness direction. For example, by performing the infiltration operation three times, a portion where the treatment liquid has penetrated three times from the surface of the elastic body to the inside, a portion where the treatment liquid has penetrated twice, and a portion where the treatment liquid has penetrated once are formed. Is done. That is, the permeation amount of the treatment liquid gradually decreases from the surface of the elastic body toward the inside, and the density of the isocyanate compound and the like becomes gradually sparse. The penetration depth of the treatment liquid is appropriately adjusted depending on the concentration and temperature of the treatment liquid, the treatment time, the compatibility between the elastic body and the organic solvent, and the like. Moreover, in the case of dipping, you may adjust with the depth which an elastic body is immersed in a process liquid.

  In the impregnation treatment, the same treatment liquid may be used, or different treatment liquids may be used. Examples of the different treatment liquid include treatment liquids in which at least one of an isocyanate compound and an organic solvent is different. When different types of isocyanate compounds are used, they may be appropriately selected in consideration of required properties (flexibility, contamination resistance, followability, durability, etc.). For example, after impregnating a treatment liquid containing an isocyanate compound with excellent contamination resistance, and then impregnating a treatment liquid containing an isocyanate compound with excellent flexibility, the rubber has better contamination resistance and followability A member can be manufactured. Moreover, when using a different kind of organic solvent, it is preferable to select considering the compatibility with a rubber base material. For example, after impregnating a treatment liquid using an organic solvent that is highly compatible with the rubber base material, and then impregnating a treatment liquid using an organic solvent that is relatively compatible with the rubber base material, the elastic body can be easily obtained. The penetration depth of the treatment liquid with respect to can be made gradually smaller. Of course, treatment liquids having different types of isocyanate compounds and organic solvents may be used. By performing the impregnation treatment using different treatment liquids, it is possible to impart characteristics according to the purpose to the rubber member.

  In the impregnation treatment, treatment liquids having different isocyanate compound concentrations may be used. In the case where treatment liquids having different isocyanate compound concentrations are used, it is preferable to permeate in order of increasing concentration. By infiltrating in the order of decreasing concentration, the treatment liquid can easily penetrate into the elastic body and can be more easily and gradually sparse.

  In the impregnation treatment, it is preferable to infiltrate the treatment liquid to a region where the rubber member is deformed to form a nip. Thereby, low hardness which is a characteristic of the foamed elastic body can be maintained, and there is no possibility that unreacted components and conductivity imparting agents inside the foamed elastic body will elute to the surface when deformed with a predetermined pressure load. .

  In the impregnation treatment, the method of curing the isocyanate compound or the like is not particularly limited as long as the isocyanate compound or the like can be cured inside the elastic layer, and after cooling to a temperature below the freezing point of the isocyanate compound or the like, There are a method of curing with moisture in the atmosphere and a method of curing with heat and moisture after volatilizing the solvent under reduced pressure. Generally, after drying at room temperature, heat treatment is performed as necessary. In addition, the heating temperature at this time is 40-150 degreeC, for example.

  The elastic body used in the present invention is obtained by curing and molding a rubber composition by mixing a rubber base material and a conductivity-imparting material added as necessary. An agent, a vulcanizing agent, a vulcanization accelerator, a filler and the like may be mixed.

  The rubber base material is not particularly limited. For example, epichlorohydrin rubber, acrylonitrile butadiene rubber (NBR), natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, chloroprene rubber, fluorine rubber, chlorinated polyethylene, acrylic rubber, silicone rubber And urethane. These rubber base materials may be used in combination, and the type and combination are appropriately selected according to the application and purpose.

  The elastic body may be imparted with conductivity by a conductivity imparting agent. As the conductivity imparting agent, an electron conductivity imparting material such as carbon black or metal powder, an ionic conductivity imparting material, or a mixture of both can be used. Although carbon black has various properties, it is preferable to use carbon fine powder. In addition, when adding an elastic body by adding carbon black, it is preferable to sufficiently disperse carbon black. This is because if the dispersibility of carbon black is poor, the compression set of the molded elastic body tends to increase. In addition, when adding a large amount of carbon black, it is preferable to use a material that does not easily affect the compression set, for example, a material having a small oil absorption, a material having a large particle size, or a material that is difficult to form a structure. Examples of the ionic conductivity-imparting material include organic salts, inorganic salts, metal complexes, ionic liquids, and the like. Examples of organic salts and inorganic salts include lithium perchlorate, quaternary ammonium salts, and sodium trifluoride acetate. Moreover, as a metal complex, halogenated ferric-ethylene glycol etc. can be mentioned, Specifically, what was described in the patent 3655364 can be mentioned. On the other hand, the ionic liquid is a molten salt that is liquid at room temperature, and is also called a room temperature molten salt, and particularly refers to a melting point of 70 ° C. or lower, preferably 30 ° C. or lower. Specific examples include those described in JP-A No. 2003-202722.

  The elastic body may be foamed. In this case, open cells or closed cells may be used, but open cells are preferred. Since the foamed elastic body is open-celled, a rubber member that is easy to impregnate the foamed elastic body with the treatment liquid and is more excellent in shape stability can be formed.

  The treatment liquid contains at least an isocyanate compound and an organic solvent, in other words, a solution obtained by dissolving at least an isocyanate compound in an organic solvent.

  As isocyanate compounds contained in the treatment liquid, 2,6-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI) and 3 , 3-dimethyldiphenyl-4,4′-diisocyanate (TODI), and the aforementioned multimers and modified products. Furthermore, the prepolymer which consists of a polyol and isocyanate can be mentioned.

  Further, the treatment liquid may contain at least one selected from a fluorine-based polymer and a silicone-based polymer. By blending these polymers into the treatment liquid, for example, when a foamed rubber member is applied to a paper feed roll or the like, adhesion of toner, paper powder, and the like can be suppressed. Thereby, in the case of the rubber member which consists of a foaming elastic body, the clogging of the cell of a surface is suppressed and the characteristic of a foamed rubber member can be maintained over a long period of time.

  The fluorine-based polymer and the silicone-based polymer are preferably those that are soluble in a predetermined organic solvent and can be chemically bonded by reacting with an isocyanate compound. Examples of the fluorine-based polymer include acrylic fluorine-based polymers, and examples of the silicone-based polymer include acrylic silicone-based polymers. The acrylic fluorine-based polymer is, for example, a solvent-soluble fluorine-based polymer having a hydroxyl group, an alkyl group, or a carboxyl group, and examples thereof include block copolymers of acrylic acid esters and fluorinated alkyl acrylates and derivatives thereof. . The acrylic silicone polymer is a solvent-soluble silicone polymer, and examples thereof include block copolymers of acrylic acid esters and acrylic acid siloxane esters, and derivatives thereof.

  Further, the treatment liquid may contain a polyether polymer. Here, the polyether polymer is preferably soluble in an organic solvent, and preferably has active hydrogen and can be chemically bonded by reacting with an isocyanate compound.

  Examples of suitable polyether polymers having active hydrogen include epichlorohydrin rubber. The epichlorohydrin rubber here refers to an unvulcanized state. Epichlorohydrin rubber is preferred because it can impart elasticity to the foamed elastic body as well as conductivity. The epichlorohydrin rubber has an active hydrogen (hydroxyl group) at the terminal, but preferably has a unit having an active hydrogen such as a hydroxyl group or an allyl group. Examples of the epichlorohydrin rubber include an epichlorohydrin homopolymer, an epichlorohydrin-ethylene oxide copolymer, an epichlorohydrin-allyl glycidyl ether copolymer, an epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer and a derivative thereof. it can.

  Examples of other suitable polyether polymers having active hydrogen include polymers having a hydroxyl group or an allyl group, such as polyols and glycols. Such a polyether polymer preferably has only one terminal rather than one having active hydrogen groups at both terminals. Moreover, it is preferable that a number average molecular weight is 300-1000. This is because elasticity can be imparted to the foamed elastic body. Examples of such polyether polymers include polyalkylene glycol monomethyl ether, polyalkylene glycol dimethyl ether, allylated polyether, polyalkylene glycol diol, polyalkylene glycol triol, and the like. By adding a polyether-based polymer to the treatment liquid, the flexibility and strength of the rubber member are improved, and as a result, there is no possibility that the surface of the rubber member is worn out or the abutting member is damaged.

  When silicone rubber is used as the rubber substrate, the treatment liquid preferably contains a reactive compound compatible with silicone rubber. The reactive compound that is compatible with silicone rubber refers to a compound that has good compatibility with silicone rubber and can react with silicone rubber or an isocyanate compound. Compared to the case where a treatment liquid containing only an isocyanate compound having low compatibility with the silicone rubber is used, the treatment liquid containing a reactive compound compatible with the silicone rubber is easily impregnated into the elastic layer. Examples of reactive compounds include silicon-containing compounds and hydrocarbon compounds, with silicon-containing compounds being particularly preferred. Examples of the silicon-containing compound include a compound having a siloxane bond, a silane coupling agent having an alkoxysilyl group, a functional silane having a chlorosilyl group or a silazane, a silylating agent, and the like. The silane coupling agent which has is preferable. Examples of the compound having a siloxane bond include terminal-modified dimethylsiloxane, condensation-type and addition-type liquid silicones, silicates, and the above-described acrylic silicone polymers. Of course, the compound having a siloxane bond may have an alkoxysilyl group at the terminal. The reactive compound compatible with the silicone rubber is preferably one that reacts with an isocyanate compound, and preferably has, for example, a hydroxyl group, an amino group, an isocyanate group, or the like. This is because a rubber member having higher strength can be formed by chemically bonding with an isocyanate compound. Moreover, it is because there is no possibility that bleeding will occur. However, in the case of a silane coupling agent having an alkoxysilyl group, it is preferable to have an isocyanate group because having an active hydrogen easily reacts with an isocyanate compound and becomes less stable.

  To the treatment liquid, as the conductivity imparting material, the above-described electronic conductivity imparting material such as carbon black and metal powder, the ionic conductivity imparting material, or a mixture of both may be added.

  Moreover, it is preferable to mix | blend 2-30 mass parts of total amounts of a fluorine-type polymer and a silicone type polymer in a processing liquid with respect to 100 mass parts of isocyanate compounds with respect to 100 mass parts. When the amount is less than 2 parts by mass, the effect of holding carbon black or the like on the foamed rubber member is reduced. On the other hand, when the polymer amount is more than 30 parts by mass, there is a problem that the electrical resistance value of the foamed rubber member is increased and the discharge characteristics are lowered, and there is a problem that an effective impregnation treatment cannot be performed due to relatively less isocyanate compound. .

  The organic solvent is not particularly limited as long as it dissolves the isocyanate compound and these fluorine-based polymer, silicone-based polymer, and polyether-based polymer contained as necessary, and does not react with the isocyanate compound. Examples include ethyl, methyl ethyl ketone (MEK), methyl ethyl isobutyl ketone (MIBK), and toluene. The organic solvent is preferably one that can easily be impregnated into the elastic body, and is preferably selected as appropriate according to the type of rubber base material of the foamed elastic body.

  The concentration of the isocyanate compound in the treatment liquid is not particularly limited as long as it does not significantly reduce the mechanical properties of the elastic body. Although the density | concentration of the isocyanate compound of a process liquid changes with combinations etc. of a rubber base material and an organic solvent, 0.1 to 10% is preferable, for example. In addition, it is easy to impregnate an elastic body, ie, the depth of impregnation tends to become deep, so that the density | concentration of the isocyanate compound of a process liquid is low. If the concentration of the isocyanate compound becomes too high, the cross-linked structure described later will be formed inside the elastic body, and the hardness will increase greatly or the stress will increase compared to the foamed elastic body before impregnation with the treatment liquid. However, there is a possibility that the rubber elasticity may be lowered.

  The rubber member of the present invention includes a paper feeding / conveying roll for performing various paper feeding / conveying operations for various OA devices such as a copying machine, a facsimile machine, various printers, a charging roll, a transfer roll, a developing roll, It is particularly suitable for use in toner supply rolls, cleaning rolls, conductive rolls, cleaning blades, transfer belts and the like.

  Hereinafter, the present invention will be described based on examples. However, the present invention is not limited to this.

(Foamed elastic body 1)
Cosmonate T-80 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) is added to 100 parts by mass of MN-3050 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), a trifunctional polyether polyol, to which water and a foam stabilizer are added and mixed. The roll was obtained by casting the part into a mold preheated to 60 ° C. in which a shaft of 6 mm in diameter was previously placed and heating for 60 minutes. The obtained roll was ground and cut off to obtain a foamed elastic body 1 having an inner diameter φ6 mm × outer diameter φ18 mm × width 320 mm and a foaming ratio of 30.0 times.

(Foamed elastic body 2)
Add 100 parts by mass of epichlorohydrin rubber (ECO), 1.0 part by mass of sulfur as a vulcanizing agent, 6.8 parts by mass of azodicarbonamide (ADCA) as a foaming agent, and 5.4 parts by mass of urea compound as a foaming aid Then, they were kneaded with a roll mixer, extruded and mounted on a φ12 mm shaft, and vulcanized and foamed at 160 ° C. for 1 hour to obtain a roll. The obtained roll was polished and cut off to obtain a foamed elastic body 2 having an inner diameter φ6 mm × outer diameter φ18 mm × width 6 mm and a foaming ratio of 3.0 times.

(Elastic body 3)
Epichlorohydrin rubber (ECO) in 100 parts by mass, di (2-ethylhexyl) phthalate (DOP) as plasticizer in 20 parts by mass, zinc white in 5 parts by mass, sulfur in 0.2 parts by mass, calcium carbonate in 20 parts by mass, stearic acid After kneading 2 parts by mass and 1.5 parts by mass of the vulcanizing agent with a roll mixer, injection molding is performed with a pipe mold in which a φ6 mm shaft is set in advance, and vulcanization is performed at 160 ° C. for 30 minutes. An unfoamed elastic body 3 having a diameter of 10 mm was obtained.

Example 1
Toluene, isocyanate prepolymer (VIBRATHANE8585: manufactured by Uniroyal Chemical Co., Ltd.) was added and mixed to prepare a treatment liquid having a concentration of 1% by mass and 5% by mass, while an isocyanate compound (MDI) was added to 2-methylpyrrolidone and mixed. A treatment liquid having a concentration of 10% by mass was prepared. Next, the foamed elastic body 1 is impregnated by spraying the treatment liquid twice by spraying the foamed elastic body 1 rotated horizontally while keeping the treatment liquid of 1% by mass at 25 ° C., and then rotating the foamed elastic body 1. The treatment liquid was impregnated more obliquely by allowing it to stand for 5 minutes. Then, the excess processing liquid was removed by rotating at higher speed. After repeating this operation with a treatment liquid having a concentration of 5% by mass and 10% by mass, the foamed elastic body 1 was naturally dried for 1 hour, and further cured by heating in an oven maintained at 120 ° C. for 1 hour. Foam rubber roll was obtained.

(Example 2)
An isocyanate compound (MDI) was added to and mixed with ethyl acetate to prepare treatment solutions having a concentration of 1% by mass, 5% by mass and 10% by mass. Next, the foamed elastic body 2 rotated sideways was immersed for 10 seconds in a treatment solution having a concentration of 1% by mass maintained at 25 ° C. from the surface to a position of 4.5 mm, and then the foamed elastic body 2 was removed from the liquid surface. The excess processing liquid was removed by pulling up and rotating at higher speed. After repeating this operation with a treatment liquid having a concentration of 5% by mass and 10% by mass, the foamed elastic body 2 was naturally dried for 1 hour and further cured by heating in an oven maintained at 120 ° C. for 1 hour. Foam rubber roll was obtained. In the case of a treatment liquid having a concentration of 5% by mass, the treatment was performed from the surface of the foamed elastic body 2 to a position 3 mm from the surface of the foamed elastic body 2 to a position of 1.5 mm from the surface of the foamed elastic body 2.

(Example 3)
A treatment liquid having a concentration of 10% by mass in which an isocyanate compound (MDI) was added and mixed in ethyl acetate was impregnated by spraying twice with a spray, and then the foamed elastic body 2 was allowed to stand for 5 minutes while rotating. Thereafter, the foamed rubber roll of Example 3 was obtained in the same manner as in Example 2 except that only the vicinity of the surface was processed by rotating at high speed to remove excess processing liquid.

Example 4
An isocyanate compound (HDI) is added to and mixed with MIBK (ethyl isobutyl ketone) to prepare a treatment liquid having a concentration of 1% by mass and a concentration of 5% by mass. On the other hand, an isocyanate prepolymer (VIBRATANE 8585: manufactured by Uniroyal Chemical Co., Ltd.) is added to butyl acetate. Was added and mixed to prepare a treatment liquid having a concentration of 10% by mass. Next, the elastic body 3 rotated in the horizontal direction while the treatment liquid having a concentration of 1% by mass is kept at 25 ° C. is impregnated by spraying the treatment liquid twice with a spray, and then the elastic body 3 is rotated. By leaving it to stand for 5 minutes, the treatment liquid was impregnated more obliquely. Then, the excess processing liquid was removed by rotating at higher speed. After repeating this operation with a treatment liquid having a concentration of 5% by mass and 10% by mass, the elastic body 3 was naturally dried for 1 hour and further cured by heating in an oven maintained at 120 ° C. for 1 hour. A rubber roll was obtained.

(Comparative Example 1)
A treatment liquid having a concentration of 20% by mass in which an isocyanate compound (MDI) is added and mixed with ethyl acetate is prepared, and instead of spraying this treatment liquid by spraying, the entire foamed elastic body 1 is immersed in the treatment liquid for 30 seconds. Were produced in the same manner as in Example 1 to obtain a foamed rubber roll of Comparative Example 1.

(Comparative Example 2)
A foam roll of Comparative Example 2 was obtained in the same manner as Comparative Example 1 except that the concentration of the treatment liquid was 1%.

(Comparative Example 3)
A foamed rubber roll of Comparative Example 3 was obtained in the same manner as in Example 2 except that a coating layer was formed by spraying a urethane paint (Neolet's R-940; manufactured by Enomoto Kasei Co., Ltd.) twice with a spray.

(Comparative Example 4)
Example 4 except that a surface treatment liquid having a concentration of 20% by mass was prepared by adding and mixing an isocyanate prepolymer (VIBRATHANE 8585: manufactured by Uniroyal Chemical Co., Ltd.) with butyl acetate and spraying the surface treatment liquid with a spray. The rubber roll of Comparative Example 4 was obtained in the same manner.

(Test Example 1) Evaluation of mechanical properties The foamed rubber rolls of the foamed elastic bodies 1-2, Examples 1-3 and Comparative Examples 1-3 were compressed 25% in the thickness direction, and the stress applied at this time was measured. .

Moreover, the change of the thickness in each site | part of the radial direction of the roll at this time was confirmed. Specifically, when the surface of the foam rubber roll is compressed by 25% in the thickness direction, with the upper surface portion of the roll 0-2 mm, the central portion of the roll surface 2-4 mm and the lower portion of the roll surface 4-6 mm. The thickness of each part of was measured. The results are shown in Tables 1-2 and FIGS.

  In addition, about the rubber roll of the elastic body 3, Example 4, and the comparative example 4, the hardness of the roll surface was measured using the micro hardness meter (made by Kobunshi Keiki Co., Ltd.). The results are shown in Table 3.

(Test Example 2) Durability test The foamed rubber rolls of the foamed elastic bodies 1 to 2 and Examples 1 to 3 and Comparative Examples 1 to 3 were applied to the photoreceptor with an amount of bite of 3 mm in an NN environment (25 ° C., 50% RH). After contacting and rotating 100,000 times, the measurement of the outer diameter change of each roll and the state of the roll and the photoreceptor were observed. The results are shown in Tables 1 and 2 and FIGS.

  The rubber rolls of the elastic body 3, Example 4, and Comparative Example 4 were brought into contact with the photoconductor with a load of 500 g applied to both ends of the shaft and tested to determine the state of each roll and photoconductor. Observed. The results are shown in Table 3.

(Test Example 3) Contamination test The foamed rubber rolls of the foamed elastic bodies 1 to 2 and Examples 1 to 3 and Comparative Examples 1 to 3 were applied to the photoconductor in an HH environment (50 ° C., 90% RH) with a biting amount of 3 mm. After contact and holding for 14 days, the presence or absence of contamination on the surface of the photoreceptor was confirmed. The case where the surface of the photoconductor was not contaminated was marked with ◯, the case where the surface of the photoconductor was hardly contaminated was marked with Δ, and the case where it was contaminated was marked with ×. The results are shown in Tables 1 and 2.

  The rubber rolls of the elastic body 3, Example 4, and Comparative Example 4 were tested by bringing them into contact with the photoconductor with a load of 500 g applied to both ends of the shaft. The results are shown in Table 3.

(Summary of test results)
In the foamed rubber roll of Example 1, the stress was about 1.01 times that of the foamed elastic body 1. In addition, the change in thickness due to deformation due to compression gradually became smaller at the upper part, middle part, and lower part, and it was confirmed that the entire roll was kept soft by dispersing stress. The outer diameter change amount in the durability test was 0.19 mm, and it was confirmed that the durability was improved 3 times or more than the foamed elastic body 1. Moreover, the foamed rubber roll of Example 1 was not confirmed to be contaminated in the contamination test.

  On the other hand, in Comparative Example 1 in which the conventional impregnation treatment was performed, the entire rubber was impregnated, and the entire rubber roll could not be kept soft. As a result, the stress increased greatly. In the durability test, It was confirmed that scratches were generated on the surface of the opposing photoconductor.

  In Comparative Example 2 in which the concentration of the processing solution is 1% in order to prevent an increase in stress and generation of scratches on the surface of the photoreceptor, the stress is approximately the same as that of the foamed elastic body 1, and in the durability test, scratches on the surface of the photoreceptor are observed. Although the occurrence was not confirmed, the outer diameter change amount was improved only about 1.2 times that of the foamed elastic body 1. In the contamination test, no contamination was observed on the surface of the photoreceptor in both Comparative Examples 1 and 2.

  On the other hand, the foamed rubber roll of Example 2 formed by immersing the foamed elastic body in the treatment solution a plurality of times has a stress that is about 1.1 times that of the foamed elastic body 2 and has a durability that is three times that of the foamed elastic body 2 or more. It was confirmed that there was an improvement. Further, no contamination on the surface of the photoreceptor was observed in the contamination test.

  Further, in Example 3 in which only the vicinity of the surface was treated, the entire rubber roll could be kept soft, so the stress was low and the outer diameter change amount was small in the durability test. However, since the amount of bite is larger than the thickness of the processed elastic body, in the contamination test, the unprocessed portion was in contact with the photoreceptor, and as a result, the photoreceptor was slightly contaminated.

  In addition, the foamed rubber roll of Comparative Example 3 having a coating layer was soft as a whole roll, so the stress was low, the outer diameter change amount in the durability test was small, and no contamination was observed on the surface of the photoreceptor in the contamination test. . However, since the hardness of the coating layer and the foamed elastic body are greatly different, each other cannot sufficiently follow the displacement (rotation), and as a result, near the interface between the foamed elastic body and the coating layer. Cracks were seen.

  The rubber roll of Example 4 molded by impregnating the non-foamed elastic body 3 had a hardness increase of about 1.05 times on the rubber surface. Further, in the durability test, the elastic body 3 was scratched on the roll surface, whereas the rubber roll of Example 4 showed no problem. Also, no contamination was confirmed in the contamination test.

  On the other hand, in the rubber roll of Comparative Example 4 subjected to the conventional surface treatment, the increase in the hardness of the rubber surface was about 1.16 times, and in the durability test, the photoconductor was found to be scratched. Further, in the contamination test, the photoreceptor was contaminated even though the concentration of the isocyanate compound in the vicinity of the roll surface was higher than that in Example 4.

  As described above, at least the density of the isocyanate compound gradually decreases from the surface of the elastic body toward the inside by the impregnation treatment in which the operation of impregnating the elastic body with the treatment liquid containing the isocyanate compound and the organic solvent is performed twice or more. It was found that the rubber member thus molded was excellent in wear resistance and stain resistance.

It is a graph which shows the result of Test Example 1 of the present invention. It is a graph which shows the result of Test Example 1 of the present invention. It is a graph which shows the result of Test Example 1 of the present invention. It is a graph which shows the result of Test Example 1 of the present invention. It is a graph which shows the result of Test Example 2 of the present invention. It is a graph which shows the result of Test Example 2 of the present invention.

Claims (5)

When the rubber composition containing the rubber base material is cured and molded, the treatment liquid containing the isocyanate compound and the organic solvent is infiltrated into the molded elastic body , and when the infiltrated isocyanate compound is cured, the operation of the infiltration is performed twice or more. By the impregnation treatment performed so that the penetration depth of the treatment liquid becomes gradually shallower in the thickness direction , at least the density of the isocyanate compound is made to penetrate from the surface of the elastic body toward the inside for each penetration depth of the operation. A method for producing a rubber member, comprising molding a rubber member that is gradually sparse. 2. The method for producing a rubber member according to claim 1 , wherein in the impregnation treatment, treatment liquids of different types of at least one of an isocyanate compound and an organic solvent are used. 3. The method for producing a rubber member according to claim 1, wherein treatment liquids having different isocyanate compound concentrations are used in the impregnation treatment. 4. 4. The method for producing a rubber member according to claim 3 , wherein in the impregnation treatment, a treatment liquid having a low concentration of the isocyanate compound is infiltrated in order. Wherein the manufacturing method of a rubber member according to any one of claims 1-4, wherein the treatment solution, fluorine-based polymer, silicone-based polymers, and also less are selected from polyether-based polymer that contains one A method for producing a rubber member.