JP2007130787A - Manufacturing method of rubber roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of efficiently manufacturing a rubber roller, which has excellent characteristics low in hardness and reduced in compression permanent strain, with good dimensional precision. <P>SOLUTION: In this manufacturing method of the rubber roller for compounding and kneading compounding agents with a liquid rubber and molding the kneaded mixture into a roller shape after defoaming to crosslink and cure the same, a photopolymerization initiator is compounded with the liquid rubber as one of the compounding agents and kneading operation is performed using a planetary type mixer to crosslink and cure the kneaded matter by the irradiation with ultraviolet rays. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rubber roller manufacturing method capable of manufacturing a rubber roller having a low hardness and a good characteristic of low compression set with a good dimensional accuracy.

  In general, when manufacturing rubber products, first, a rubber composition is prepared by blending raw materials rubber with compounding agents such as reinforcing agents, fillers, softeners, anti-aging agents and the like, and then kneading the rubber composition. A non-crosslinked rubber composition is prepared by adding a crosslinking (vulcanization) agent, a crosslinking (vulcanization) accelerator, etc. to the product, and after this is molded into a desired shape, it is subjected to crosslinking curing or simultaneously with molding. A method of obtaining a crosslinked rubber product by performing crosslinking and curing is employed.

  In this case, the reinforcing agent and filler are often in the form of powder and are likely to be scattered during kneading with the raw rubber. Therefore, in order to complete kneading in a short time, it is necessary to use a closed kneader to prevent scattering of these compounding agents, and kneading work is performed using a closed kneader such as a Banbury or a kneader. (For example, refer to Patent Documents 1 and 2 below).

  Here, in various applications such as various rollers and blades used in electrophotographic apparatuses such as copying machines, facsimiles, and printers, it is often required to reduce the hardness of rubber materials. In order to reduce hardness (reduced hardness) or improve workability during production, a large amount of liquid rubber is also blended with raw rubber (for example, see Patent Document 2 below).

  However, in the method of mixing the liquid rubber with the solid rubber, it is difficult to sufficiently reduce both the compression set and the hardness, and it may not be possible to sufficiently meet the required requirements. Further, since liquid rubber and other compounding agents are kneaded into the raw rubber, each of these materials is put into the above-mentioned closed kneader and kneaded. In that case, the liquid rubber is used in the closed kneader. There is a problem in that the other compounding agents adhere to the rotor surface and are difficult to disperse in the liquid rubber, and the kneading efficiency decreases.

  In addition, as a developing roller used in an electrophotographic apparatus, a conductive roller formed by blending a silicone rubber or urethane rubber with a conductive agent is often used (for example, see Patent Document 3 below). In general, it is manufactured by injection molding using a two-component LIM molding machine.

  However, when producing a conductive rubber roller by an injection molding method using this LIM molding machine, the molding time for crosslinking is long, and a large number of injection molding machines are required to obtain good productivity. There's a problem. In addition, the polishing step after molding is also omitted from the viewpoint of environmental protection, which necessitates a large amount of highly accurate high-priced molds, which increases the manufacturing cost. .

JP 2000-129037 A JP 2005-154545 A JP 2004-74431 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a rubber roller that can easily manufacture a rubber roller having a low hardness and a good performance with a small compression set with a good dimensional accuracy. And

  As a result of intensive studies to achieve the above object, the present inventor has blended a desired compounding agent as necessary with rubber, kneaded, molded into a roller shape, crosslinked and cured, and manufactured a rubber roller. The rubber material is obtained by performing the kneading operation using a planetary mixing device, particularly a planetary mixing and defoaming device that revolves while the container containing the object rotates and defoams while kneading the object. Even if liquid rubber such as low molecular weight terminal acrylic-modified butadiene rubber or terminal acrylic-modified isoprene rubber is used, a good uncrosslinked rubber composition in which the compounding agent is sufficiently and satisfactorily dispersed in these liquid rubbers and has very few bubbles. It can be efficiently prepared without inconvenience due to adhesion of liquid rubber, and a rubber roller having good characteristics with low hardness and small compression set can be obtained. It was. Furthermore, by blending a photopolymerization initiator as one of the above compounding agents and performing crosslinking and curing by ultraviolet irradiation, the crosslinking and curing can be completed in a short time and a rubber roller can be produced efficiently at low cost. It has been found that a roller with high dimensional accuracy can be reliably obtained without causing large shrinkage as in the case of crosslinking, and the present invention has been completed.

  Accordingly, the present invention is a method for producing a rubber roller in which a compounding agent is blended in a liquid rubber, kneaded, defoamed, and then molded into a roller shape and crosslinked and cured, and a photopolymerization initiator is compounded as one of the above compounding agents. In addition, the present invention provides a method for producing a rubber roller, characterized in that the kneading operation is performed using a planetary mixer and the crosslinking and curing is performed by ultraviolet irradiation.

  According to the method for producing a rubber roller of the present invention, a rubber roller having excellent characteristics with low hardness and small compression set can be efficiently produced with good dimensional accuracy.

Hereinafter, the present invention will be described in more detail.
As described above, the method for producing a rubber roller of the present invention is a method in which a liquid polymerization is mixed with a photopolymerization initiator and molded into a roller shape, and this is crosslinked and cured by ultraviolet irradiation.

  The liquid rubber used in the present invention is not particularly limited as long as it is liquid at room temperature and exhibits elasticity by being cross-linked by photopolymerization by using a photopolymerization initiator, depending on the use of the rubber roller, etc. For example, terminal acrylic modified liquid butadiene rubber, terminal acrylic modified hydrogenated liquid butadiene rubber, terminal acrylic modified liquid isoprene rubber, terminal acrylic modified hydrogenated liquid isoprene rubber, methacryloyl modified liquid isoprene rubber, and the like can be exemplified. 1 type (s) or 2 or more types can be used. Among these, methacryloyl-modified liquid isoprene rubber, terminal acrylic-modified liquid isoprene rubber, terminal acrylic-modified liquid butadiene rubber and the like are preferably used in the present invention. The liquid rubber used in the present invention preferably has a number average molecular weight of 2000 to 50000.

  Here, depending on the case, two or more liquid rubbers may be mixed and used. In some cases, solid rubber can be blended with liquid rubber within a range not departing from the object of the present invention, but in the present invention, only solid rubber is used as a raw rubber component without blending any solid rubber. Preferably, a rubber cross-linked product having a low hardness and a small compression set can be obtained more reliably. Examples of the solid rubber in the case of blending the solid rubber include natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, ethylene propylene rubber, chloroprene rubber, nitrile rubber, epichlorohydrin rubber, and the like.

  In the present invention, a photopolymerization initiator is blended with the liquid rubber, and crosslinking and curing is performed by ultraviolet irradiation. In this case, there is no restriction | limiting in particular as a photoinitiator, A well-known thing can be used. For example, 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl ketal, alkoxyacetophenone, benzyldimethyl ketal, benzophenone and 3,3-dimethyl-4-methoxy Benzophenone, benzophenone derivatives such as 4,4-diaminobenzophenone, benzoyl alkylbenzoate, bis (4-dialkylaminophenyl) ketone, benzyl derivatives such as benzyl and benzylmethyl ketal, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl Ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, xanthone, thioxanthone Thioxanthone derivatives, fluorene, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -Phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, 2-benzyl-2-dimethylamino-1- (morpholinophenyl) -butanone-1, etc. These may be used alone or in combination of two or more. Among these, 1-hydroxy-cyclohexyl-phenyl-ketone (“Irgacure 184D” manufactured by Ciba Specialty Chemicals), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Irgacure 819” manufactured by Ciba Specialty Chemicals) 2-hydroxy-2-methylpropiophenone Ciba Specialty Chemicals “Irgacure 1173”) is preferably used. The amount of the photopolymerization initiator is appropriately set according to the type of polymerization initiator used, the type of liquid rubber, and the molding method. -10 parts by mass, particularly 0.1-5 parts by mass.

  In the present invention, the photopolymerization initiator is added to the liquid rubber, kneaded and defoamed to prepare an uncrosslinked liquid rubber composition. The uncrosslinked rubber composition includes the photopolymerization initiator. In addition to the above, an appropriate amount of a known compounding agent such as a filler, a conductive agent, a crosslinking accelerator, a reinforcing agent, a softening agent, and an anti-aging agent can be added and mixed as necessary.

  Examples of the filler include carbon black, calcium carbonate, silica, clay, magnesium carbonate, magnesium silicate and the like.

  As the conductive agent, either an electronic conductive agent or an ionic conductive agent can be used. As the electronic conductive agent, gas furnaces such as ketjen black and acetylene black, oil furnace black including ink black, thermal black, and channel black. , Carbon black such as lamp black. Examples of ionic conductive agents include dodecyltrimethylammonium such as tetraethylammonium, tetrabutylammonium and lauryltrimethylammonium, octadecyltrimethylammonium such as stearyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified aliphatic dimethylethylammonium. Ammonium salts such as perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate; lithium, sodium, calcium Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl sulfate, sulfone of alkali metals or alkaline earth metals such as magnesium Such salts are exemplified. In the present invention, an ionic conductive agent that does not decrease the transparency of the composition is preferably used because it is crosslinked and cured by ultraviolet irradiation.

  Examples of the crosslinking accelerator include ethylene dimethacrylate, trimethylolpropane trimethacrylate, triallyl isocyanurate, triallyl cyanurate, and the softening agent includes paraffinic oil, naphthenic oil, aromatic oil, Adipic acid ester, sebacic acid ester and the like are exemplified, and examples of the antiaging agent include phenolic antiaging agent, imidazole antiaging agent and amine antiaging agent.

  Moreover, it is also preferable to mix | blend a ultraviolet absorber and a light stabilizer depending on a use, and 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5- 5) as a ultraviolet absorber. Methyl-2-hydroxyphenyl-5-chlorobenzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotoazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, etc. Illustrative examples of the light stabilizer include bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, Examples include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole.

  As described above, in the present invention, first, a liquid rubber, a photopolymerization initiator, and other compounding agents are kneaded and defoamed to prepare an uncrosslinked liquid rubber composition. In this case, in the present invention, the kneading operation is performed using a planetary mixer instead of a Banbury mixer or a kneader. As the planetary mixing device used, a general planetary mixing device such as a so-called planetary mixer in which a paddle, a stirring arm, a stirring blade, etc. rotate and revolves (planetary motion) can be used. A planetary mixing / defoaming device that revolves while the container containing the material rotates and defoams while kneading the object is particularly preferably used. By using such a planetary mixing / defoaming device, the above compounding agent can be uniformly and efficiently dispersed in the liquid rubber without causing any inconvenience related to the adhesion of the liquid rubber, and kneading and mixing operations can be performed. At the same time, by performing defoaming, a very high quality uncrosslinked liquid rubber composition having almost no bubbles can be efficiently obtained. In addition, as such a planetary mixing and defoaming device, AR-100, ARV-200, AR-250, AR-500, ARV-1000, ARV-300 and Kurashiki Boseki Co., Ltd. Commercially available devices such as Mazerustar KK-50S, KK-100, KK-300, KK-10000 can be used.

  The mixing and kneading conditions (stirring speed, stirring temperature, stirring time, etc.) are not particularly limited, and may be set as appropriate according to the type of liquid rubber, compounding agent, compounding amount of the compounding agent, and the like.

  The uncrosslinked rubber composition prepared by the kneading operation is molded into a roller shape and crosslinked and cured by ultraviolet irradiation to form a rubber roller. In this case, the molding of the liquid rubber composition is not particularly limited, but a method of applying an uncrosslinked liquid rubber composition to the outer periphery of the shaft using a die coater is preferably employed, and thereby the outer periphery of the shaft is used. The roller on which the rubber layer is formed can be efficiently molded.

  Then, the rubber layer made of an uncrosslinked liquid rubber composition formed on the outer periphery of the shaft is irradiated with ultraviolet rays for a predetermined time to be cured by crosslinking to obtain a rubber roller having an elastic layer made of a rubber cross-linked product formed on the outer periphery of the shaft. be able to. In this case, the rubber layer on the outer periphery of the shaft cross-linked and cured by photopolymerization is cross-linked and hardened with little dimensional change due to shrinkage or the like, and a rubber roller excellent in dimensional accuracy and smoothness can be obtained with certainty. In addition, the conditions of ultraviolet irradiation can be made into the normal conditions according to the thickness of the said rubber layer, the compounding composition of a rubber composition, the intensity | strength of a light source, etc.

  The rubber roller obtained by the production method of the present invention has physical properties of low hardness and low compression set as described above, but there is no particular limitation on its use, and various uses can be achieved by the production method of the present invention. A rubber roller can be manufactured. In this case, the resulting rubber roller has a high uniformity of compounding agents such as fillers and conductive agents dispersed and blended, low hardness, low compression set, and excellent dimensional accuracy. Examples of applications in which toner is effectively used include toner conveying rollers, developing rollers, charging rollers, transfer rollers, and paper feed rollers used in electrophotographic apparatuses and electrostatic recording apparatuses such as printers and copiers. It is particularly preferably used as a roller.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
[Examples 1 to 3]
A compounding agent is blended in rubber with the composition shown in Table 1 below, and is kneaded and defoamed under the following conditions using a planetary mixing and defoaming device ("AR-25" manufactured by Sinky Corporation). An uncrosslinked liquid rubber composition was prepared. In addition, the mixing | blending in following Table 1 is a weight part.
Kneading condition equipment: Planetary mixing and defoaming device Autorotation speed: 400 rpm
Revolution speed: 800rpm
Kneading time: 5 minutes

Next, using the die coater, the obtained uncrosslinked liquid rubber composition was applied to the outer periphery of a metal shaft (diameter 10 mm), and a rubber layer having a thickness of 3 mm was formed on the outer periphery of the metal shaft over a length of 240 mm. . This is made of a liquid rubber composition by moving it into an ultraviolet irradiation device and irradiating the ultraviolet ray with an irradiation intensity of 700 mW / cm ² for 10 seconds using a UV irradiation device (250 W type) manufactured by Ushio Electric Co., Ltd. The rubber layer was crosslinked and cured to produce a conductive rubber roller having a rubber layer formed on the outer periphery of the shaft. The integrated light quantity at this time was 1.2 J / cm ² .

[Comparative Example 1]
First, a roller molding die comprising a lower lid, a cylindrical mold, and an upper lid was prepared. Then, a core metal (diameter 10 mm, made of SUS304) whose surface is treated with an adhesion primer as a shaft is set concentrically and vertically in a cylindrical mold having a lower lid fitted externally, and then the core metal and the cylindrical shape Liquid silicone uncrosslinked rubber compounded with conductive carbon black was injected and filled into the gap between the mold and heated under conditions of 150 ° C. × 45 minutes. Thereafter, this was demolded to obtain a conductive roller having an outer shape of 20 mm and a length of 285 mm.

[Comparative Example 2]
A cored bar was set in the same mold as in Comparative Example 1, and two types of monomer components were mixed and injected into the gap between the cored bar and the cylindrical mold to cause a polymerization reaction. Thereafter, this was demolded to obtain a conductive roller having an outer shape of 20 mm and a length of 285 mm.

The following items were evaluated for each rubber roller obtained in Examples 1 to 3 and Comparative Examples 1 and 2. The results are shown in Table 1.
[Asker C hardness]
Measurement was performed in accordance with a vulcanized rubber hardness test method defined in JIS K6253 with the obtained roller.
[Compression set]
Measurement was performed in accordance with a vulcanized rubber compression set test method defined in JIS K6262.
[Roller volume resistance]
A load of 500 g was applied to both ends of the roller and pressed against the copper plate, and a resistance value was measured by applying a voltage of 100 V using a resistivity meter R8340A (manufactured by Advantest). The measurement was performed at room temperature (23 ° C.).
[Roller surface properties]
The roller surface was measured using a three-dimensional microscope to evaluate the smoothness.
[Roller runout]
Using a laser scanning micrometer “LSM-3100” manufactured by Mitutoyo Corporation, the runout width of the outer peripheral surface of the roller was measured when the roller was rotated about its axis.

ＵＣ２０３：クラレ社製液状イソプレンゴム
ＴＥ２０００：日本曹達社製液状ブタジエンゴム
ＢＡＣ−４５：大阪有機化学工業社製末端アクリル変性液状ブタジエンゴム
イルガキュア１８４Ｄ：チバスペシャルティーケミカルズ社製光重合開始剤（１−ヒドロキシ−シクロヘキシル−フェニル−ケトン）
導電剤： 昭島化学工業社製イオン導電剤「ＭＰ−１００」（過塩素酸ナトリウムポリオール錯塩）

UC203: Liquid isoprene rubber TE2000 manufactured by Kuraray Co., Ltd. Liquid butadiene rubber BAC-45 manufactured by Nippon Soda Co., Ltd. Terminal acrylic modified liquid butadiene rubber Irgacure 184D manufactured by Osaka Organic Chemical Industries, Ltd. Photopolymerization initiator (1- Hydroxy-cyclohexyl-phenyl-ketone)
Conductive agent: Ion conductive agent "MP-100" (sodium perchlorate polyol complex salt) manufactured by Akishima Chemical Industry Co., Ltd.

  As shown in Table 1, according to the rubber roller manufacturing method of the present invention, it is confirmed that a high-performance rubber roller having low hardness, small compression set, good characteristics, and excellent dimensional accuracy can be reliably obtained. It was done.

Claims (8)

  In a method of manufacturing a rubber roller, which is blended with liquid rubber, kneaded, defoamed, and then molded into a roller and crosslinked and cured, a photopolymerization initiator is blended as one of the above blending agents, and planetary mixing A method for producing a rubber roller, wherein the kneading operation is performed using an apparatus, and the crosslinking and curing is performed by ultraviolet irradiation.   The liquid rubber is selected from the group consisting of terminal acrylic modified liquid butadiene rubber, terminal acrylic modified hydrogenated liquid butadiene rubber, terminal acrylic modified liquid isoprene rubber, terminal acrylic modified hydrogenated liquid isoprene rubber, and methacryloyl modified liquid isoprene rubber. The method for producing a rubber roller according to claim 1, wherein the rubber roller is one type or two or more types.   The method for producing a rubber roller according to claim 1 or 2, wherein the liquid rubber has a number average molecular weight of 2,000 to 50,000.   The photopolymerization initiator is 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, 2-methyl-1- [4- (methylthio) phenyl]. One selected from the group consisting of 2-morpholinopropane-1,2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2-benzyl-2-dimethylamino-1- (morpholinophenyl) -butanone-1 Or the manufacturing method of the rubber roller of any one of Claims 1-3 which is 2 or more types.   5. The planetary mixing / defoaming device is used as the planetary mixing device, wherein a planetary mixing / defoaming device that revolves while a container containing an object rotates and defoams while kneading the object is used. Of manufacturing rubber roller.   The manufacturing method of the rubber roller of any one of Claims 1-5 which mix | blend a electrically conductive agent as one of the compounding agents.   The method for producing a rubber roller according to claim 6, wherein the conductive agent is an ionic conductive agent.   The uncrosslinked liquid rubber composition is formed into a roller shape by blending a liquid rubber with a compounding agent and kneading and applying the defoamed uncrosslinked liquid rubber composition to the outer periphery of the shaft using a die coater. The manufacturing method of the rubber roller of any one of -6.