JP4900584B2 - Thermal fixing roll or fixing belt - Google Patents

Description

The present invention relates to a heat fixing roll or fixing belt is formed using a high thermal conductivity of the heat fixing roll or fixing belt silicone rubber composition, and more particularly, despite having high thermal conductivity, the high temperature thermosetting exposed capable of forming a small silicone rubber change in physical properties even, thermal fixing, which is formed by using a particular additional or organic peroxide curing type heat fixing roll or fixing belt silicone rubber composition The present invention relates to a roll and a fixing belt.

  Silicone rubber is excellent in electrical insulation, heat resistance, weather resistance, and flame resistance, so it is used in various fields such as electrical and electronic equipment such as home appliances and computers, transportation equipment parts, OA equipment, and architectural applications. Yes. In particular, in recent years, it has been used as a coating material for fixing rolls such as heat radiating parts of computers, heater rolls, and pressure rolls of copying machines and laser beam printers, taking advantage of its heat resistance. Recently, as the speed of copying and color copying has become widespread, the fixing roll is also required to have low hardness, which cannot be handled with conventional metals or fluororesins. Many types of coating are used. In particular, the heat roll rubber used here is required to have high thermal conductivity in order to shorten the waiting time when starting the machine and from the viewpoint of energy saving of the machine itself. Therefore, low compression set is required. However, since the heat conductivity of silicone rubber itself is not high, a method of adding a filler having high heat conductivity is generally performed. Such silicone rubbers are proposed in Japanese Patent Application Laid-Open No. 58-219259 (Patent Document 1), Japanese Patent Application Laid-Open No. 3-221982 (Patent Document 2), Japanese Patent Application Laid-Open No. 10-39666 (Patent Document 3), and the like. What has been used has been used. In these, silica, alumina, magnesium oxide or the like is blended as a thermally conductive filler in conventionally used silicone rubber. However, in order to improve thermal conductivity, it is necessary to add a large amount of filler. As a result, roll hardness is deteriorated due to deterioration of rubber compression set required for a rubber roller, reduction in heat resistance and excessive filling of filler. However, there are adverse effects such as increasing the thickness and making molding difficult.

JP 58-219259 A JP-A-3-221982 JP-A-10-39666 JP 2002-2730032 A JP 2000-089600 A JP 2003-208252 A Japanese Patent Laid-Open No. 9-328365 JP 2003-137528 A

The present invention has been made in view of the above circumstances, and has a high thermal conductivity, a heat fixing roll excellent in heat resistance and elastic modulus, a high heat conductive heat fixing roll that enables a fixing belt, or a silicone rubber composition for a fixing belt. It is an object of the present invention to provide a fixing roll and a fixing belt using the object.

  As a result of various investigations on materials having high thermal conductivity and excellent heat resistance, the present inventor has obtained high thermal conductivity, low compression set, and heat resistance by blending metal silicon powder with the silicone rubber composition. As a result, it was found that the cured silicone rubber having excellent heat resistance and high heat conductivity and excellent heat resistance can be effectively used as a fixing roll and a fixing belt of various copying machines and printers. It is a thing.

  In addition, about utilization to fillers, such as a metal silicon powder, for thermal conductivity improvement, Unexamined-Japanese-Patent No. 2002-270032 electrically conducts by combined use of carbon powder and SiOx (0.5 <X <1.5) powder. Although there is a description of imparting properties, there is no description of metallic silicon powder and thermal conductivity. Japanese Patent Laid-Open Nos. 2000-089600 and 2003-208252 have a description of using silicon carbide as a heat conductive material, but there is no description of using metal silicon powder. In addition, Japanese Patent Application Laid-Open No. 9-328365 and Japanese Patent Application Laid-Open No. 2003-137528 describe that metal silicon is used as a starting material for silicon nitride or spherical silica. For this purpose, there is no description of organopolysiloxane blended with metal silicon powder to produce a high thermal conductive silicone rubber.

Therefore, the silicone rubber composition used for the fixing roll and fixing belt of the present invention is:
(A) 100 parts by mass of an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) Metallic silicon powder having an average particle size of 100 μm or less 20 to 500 parts by mass (C) A highly heat conductive heat fixing roll or fixing containing a curing agent in an amount capable of curing the component (A). Ru silicone rubber composition der belt. In this case, the metal silicon powder of component (B) is pulverized by a pulverization method, and is a pulverized metal silicon powder having an average particle diameter of 1 to 50 μm or a spherical metal silicon powder having an average particle diameter of 1 to 50 μm. Is preferred. Moreover, it is preferable that the heat conductivity of hardened | cured material is 0.5 W / mK or more.

Therefore , the present invention provides a fixing roll in which at least one silicone rubber layer is formed on the outer peripheral surface of a roll shaft, and the silicone rubber forming the silicone rubber layer cures the silicone rubber composition. A fixing roll comprising a fluororesin layer or a fluororubber layer formed on the outer peripheral surface of a roll shaft via at least one silicone rubber layer, wherein the silicone rubber layer A fixing roll formed by curing the above-mentioned silicone rubber composition, and a belt base material having at least one silicone rubber layer, and a single layer or fluorine A fixing belt formed with a resin layer or a fluororubber layer, wherein the silicone rubber forming the silicone rubber layer is the above-mentioned silicone belt. To provide a fixing belt which is characterized in that it is made by curing a Kongomu composition.

  The fixing roll and fixing belt of the present invention have high thermal conductivity and excellent long-term durability at high temperatures.

The component (A) of the silicone rubber composition for high heat conductivity heat fixing roll or fixing belt of the present invention contains an alkenyl group bonded to at least two silicon atoms in one molecule, and is liquid or raw rubber-like at room temperature. Diorganopolysiloxanes represented by the following average composition formula (1) can be used.
R ¹ _a SiO _{(4-a) / 2} (1)

In the formula, R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having the same or different carbon number of 1 to 10, preferably 1 to 8, and a is 1.5 to 2.8, preferably 1. It is a positive number in the range of 8 to 2.5. Here, examples of the unsubstituted or substituted monovalent hydrocarbon group bonded to the silicon atom represented by R ¹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group. , Pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, alkyl group such as decyl group, aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenylethyl group, phenylpropylene An aralkyl group such as a ruthel group, a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, an alkenyl group such as an octenyl group, and some or all of the hydrogen atoms of these groups Substituted by halogen atoms such as fluorine, bromine and chlorine, cyano groups, etc., such as chloromethyl group, chloro Propyl group, bromoethyl group, trifluoropropyl group, but cyanoethyl group and the like, Preferably, at least 90 mol% of all R ¹ is a methyl group.

Further, at least two of R ¹ must be alkenyl groups (preferably having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and particularly preferably a vinyl group). The alkenyl group content in the organopolysiloxane is 1.0 × 10 ^{−6 to} 5.0 × 10 ⁻³ mol / g, particularly 5.0 × 10 ^{−6 to} 1.0 × 10 ⁻³ mol / g. g is preferable. When the amount of the alkenyl group is less than 1.0 × 10 ⁻⁶ mol / g, crosslinking is insufficient and gelation occurs, and when the amount is more than 5.0 × 10 ⁻³ mol / g, the crosslinking density is low. There is a possibility that the rubber becomes too high and becomes brittle rubber. The alkenyl group may be bonded to the silicon atom at the end of the molecular chain, may be bonded to the silicon atom in the middle of the molecular chain (that is, non-terminal of the molecular chain), or may be bonded to both. The molecular weight is liquid or raw rubber at room temperature, and the degree of polymerization is preferably 50 to 50,000, more preferably 80 to 20,000.

The structure of this organopolysiloxane basically has a main chain, for example, a diorganosiloxane unit such as a dimethylsiloxane unit, a diphenylsiloxane unit, a methylphenylsiloxane unit, a methyltrifluoropropylsiloxane unit, or a vinylmethylsiloxane unit. (R ¹ ₂ SiO _2/2 ), and both ends of the molecular chain are, for example, trimethylsiloxy group, vinyldimethylsiloxy group, divinylmethylsiloxy group, trivinylsiloxy group, vinyldiphenylsiloxy group, vinylmethylphenylsiloxy Has a linear structure blocked with a triorganosiloxy group (R ¹ ₃ SiO _1/2 ) such as a phenyl group, phenyldimethylsiloxy group, diphenylmethylsiloxy group, etc., but partially branched structure, cyclic structure, etc. It may be.

  The component (B) is a highly heat conductive inorganic powder for imparting heat conductivity to the composition of the present invention, and the silicone rubber composition of the present invention is a highly heat conductive inorganic powder to the organopolysiloxane (A). As the powder, the metal silicon powder (B) is blended. Metallic silicon has good thermal conductivity, low Mohs hardness, and the characteristics of metallic silicon are that it can be crushed easily when hit, and its malleability is low. . Therefore, it is easy to make fine particles by pulverization and has excellent dispersibility in polyorganosiloxane. In addition, a very thin natural oxide film is formed on the surface of the metal silicon powder, and the formed film is the same as glass, is resistant to heat, acid and dirt, does not flow electricity, and is stable to heat.

  Here, the method for producing the metal silicon powder used in the present invention is not particularly limited, but a product obtained by reducing silica into metal silicon by pulverization with an existing crusher or pulverizer such as a ball mill. , Metal silicon (wafer) generated from the semiconductor manufacturing process, etc., fine powder made from cutting scraps, etc., powdered by a pulverization method, metal silicon melted at a high temperature is atomized by a gas phase method, Spherical metal silicon powders such as those that have been cooled and solidified into spherical particles (here, “spherical” or “spherical” means that the surface of each particle has a smooth shape with no sharp edges. In general, the ratio of major axis / minor axis (aspect ratio) is 1.0 to 1.4, preferably about 1.0 to 1.2. Single crystal or polycrystal of structure is optional A. The purity of the finely divided metal silicon powder is not particularly limited, but is preferably 50% or more (that is, 50 to 100%) from the viewpoint of imparting thermal conductivity, and more preferably 80% or more (80 To 100%), more preferably 95% or more (95 to 100%). High-purity metallic silicon powder has no defects in the natural oxide film on the surface and has good high-temperature thermal stability.

  The metal silicon powder used in the present invention has an average particle size of 100 μm or less, preferably 1 to 50 μm, more preferably 1 to 25 μm, particularly 2 to 25 μm. Particles having an average particle diameter of less than 1 μm are difficult to produce and may be difficult to mix in large quantities. When the particle diameter exceeds 100 μm, not only the mechanical strength of the rubber cured product may be impaired. There is a risk of problems in surface performance as a roll or the like.

The average particle diameter can be determined as a cumulative weight average value D ₅₀ (or median diameter) or the like using a particle size distribution measuring apparatus such as a laser light diffraction method.

  The component (B) metal silicon powder is a silane coupling agent or a partial hydrolyzate thereof, an alkylalkoxysilane or a portion thereof for the purpose of improving the thermal stability of the silicone rubber composition and the compoundability of the powder. It may be surface-treated with a hydrolyzate, an organic silazane, a titanate coupling agent, an organopolysiloxane oil, a hydrolyzable functional group-containing organopolysiloxane, or the like. In these treatments, the inorganic powder itself may be treated in advance, or may be treated at the time of mixing with the component (A).

  (B) The compounding quantity of the metal silicon powder of a component is 20-500 mass parts with respect to 100 mass parts of (A) component, Preferably it is 50-300 mass parts. When the amount is less than 20 parts by mass, high thermal conductivity cannot be obtained, and when the amount exceeds 500 parts by mass, physical properties such as rubber strength are significantly reduced.

  In the present invention, other heat conductive materials may be used in combination as long as the low compression set and heat resistance are not impaired. In that case, it is desirable that 50% or more of the volume volume ratio of the whole heat conductive material blended in the component (A) is the metal silicon powder of the present invention.

  As other heat conductive materials, known materials can be used and are not particularly limited. Specifically, alumina, aluminum, silicon carbide, silicon nitride, magnesium oxide, magnesium carbonate, zinc oxide, nitriding are used. Aluminum, graphite, fibrous graphite, etc. are mentioned.

  The curing agent of the component (C) of the present invention is a known curing agent or organic peroxide curing agent by addition reaction.

  In this case, the addition reaction curing agent is a combination of (C-1) an organohydrogenpolysiloxane and (C-2) an addition reaction catalyst.

The organohydrogenpolysiloxane (C-1) acts as a crosslinking agent for curing the composition by the hydrosilylation addition reaction with the alkenyl group-containing organopolysiloxane of the component (A). The average composition formula (2) )
R ² _b H _c SiO _{(4-bc) / 2} (2)
(Wherein R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, b is 0.7 to 2.1, particularly 0.8 to 2.0, and c is 0.8. 001 to 1.0 and b + c is a positive number satisfying 0.8 to 3.0, particularly 1.0 to 2.5.)
At least 2, preferably 3 or more (usually about 3 to 200), more preferably 3 to 100, especially 3 to 50 silicon atom-bonded hydrogen atoms (SiH group) in one molecule. Those having the following are preferably used.

  This silicon-bonded hydrogen atom is bonded to both silicon atoms bonded to both silicon atoms at the molecular chain end and those bonded to the silicon atom in the middle of the molecular chain (non-terminal molecular chain). It may be a thing.

Here, as R ^2, there may be mentioned the same groups as R ^l in formula (1), preferably those free of aliphatic unsaturated bonds such as alkenyl radicals.

Examples of the organohydrogenpolysiloxane include tris (dimethylhydrogensiloxy) methylsilane, tris (dimethylhydrogensiloxy) phenylsilane, 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetra. Methylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, both ends trimethylsiloxy group-blocked methylhydrogenpolysiloxane, both ends trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane Polymer, both ends dimethylhydrogensiloxy-blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy-blocked dimethylsiloxane methylhydrogen Hexane copolymers, both end trimethylsiloxy-blocked methylhydrogensiloxane-diphenylsiloxane copolymers, both end trimethylsiloxy-blocked methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane _{copolymer, (CH 3) 2 HSiO 1} / _A copolymer comprising ₂ units and SiO _4/2 units, a copolymer comprising (CH ₃ ) ₂ HSiO _1/2 units, SiO _4/2 units and (C ₆ H ₅ ) SiO _3/2 units, etc. In addition, in these exemplified compounds, a part or all of the methyl group may be another alkyl group such as an ethyl group or a propyl group, an aryl group such as a phenyl group, or a halogen-substituted alkyl group such as a 3,3,3-trifluoropropyl group. And the like substituted with.

  The molecular structure of this organohydrogenpolysiloxane may be any of linear, cyclic, branched, and three-dimensional network structures, but the number (or degree of polymerization) of silicon atoms in one molecule is 2 to 1. 1,000, preferably 3 to 500, more preferably 3 to 300, and particularly preferably about 4 to 150 can be used.

  The compounding amount of the organohydrogenpolysiloxane is 0.1 to 50 parts by mass, more preferably 0.1 to 30 parts by mass, and still more preferably 0.3 to 100 parts by mass of the organopolysiloxane of the component (A). It is preferable to set it to -30 mass parts, especially 0.3-20 mass parts.

  In addition, this organohydrogenpolysiloxane has a molar ratio of hydrogen atoms bonded to silicon atoms in the component (C-1) to alkenyl groups bonded to silicon atoms in the component (A) (that is, SiH groups) is 0. 0.5-5 mol / mol, preferably 0.8-4 mol / mol, more preferably 1-3 mol / mol.

  The addition reaction catalyst (C-2) is a catalyst for promoting the hydrosilylation addition reaction between the alkenyl group bonded to the silicon atom in the component (A) and the SiH group of the organohydrogenpolysiloxane (C-1). Examples of the addition reaction catalyst include platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and an olefin, platinum bisacetoacetate, etc. Examples thereof include platinum group metal catalysts such as platinum-based catalysts, palladium-based catalysts, and rhodium-based catalysts. In addition, although the compounding quantity of this addition reaction catalyst can be made into a catalyst quantity, 0.5-1,000 ppm normally with respect to the total mass of (A) and (C-1) component as a platinum group metal normally. About 1 to 500 ppm is preferably blended.

  On the other hand, as the organic peroxide curing agent (C-3), any organic peroxide curing type organopolysiloxane composition can be used as a catalyst for promoting the crosslinking reaction of the component (A). Well known ones can be used. For example, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-bis (2,5- t-butylperoxy) hexane, di-t-butylperoxide, t-butylperbenzoate, 1,1-bis (t-butylperoxycarboxy) hexane, and the like, but are not particularly limited thereto. Absent.

  The addition amount of the organic peroxide is a catalyst amount and may be appropriately selected according to the curing rate. Usually, it is 0.1 to 10 parts by mass, preferably 0 to 100 parts by mass of the component (A). .2 to 2 parts by mass.

  In the present invention, the above addition crosslinking and organic peroxide crosslinking may be used in combination. Note that addition crosslinking is recommended for curing the liquid organopolysiloxane composition.

  In the present invention, it is optional to add a conductive material to obtain a conductive silicone rubber composition. The type and blending amount of the conductive material are not limited, but conductive carbon black, conductive zinc white, metal powder and the like can be used, and the conductive material may be used alone or in combination of two or more. As the carbon black, those usually used in conductive rubber compositions can be used, and examples thereof include acetylene black, conductive furnace black (CF), super conductive furnace black (SCF), extra conductive furnace black (XCF), Examples thereof include conductive channel black (CC), furnace black and channel black heat-treated at a high temperature of about 1,500 to 3,000 ° C. Specifically, Denka Black (manufactured by Electrochemical Co., Ltd.), Shaunigan acetylene black (manufactured by Shaunigan Chemical Co., Ltd.), etc. are used as acetylene black, Continex CF (manufactured by Continental Carbon Co.), Vulcan, etc. as conductive furnace black. C (manufactured by Cabot) etc., as super conductive furnace black, Continex SCF (manufactured by Continental Carbon), Pulcan SC (manufactured by Cabot), etc., Asahi HS-500 (Asahi Carbon) ), Pulkan XC-72 (manufactured by Cabot Corp.), etc., examples of the conductive channel black include Kourax L (manufactured by Degussa), etc., and Ketjen Black EC which is a kind of furnace black It is also possible to use a fine-Ketchen black EC-600JD (manufactured by Ketchen Black International Co., Ltd.). In furnace black, the amount of impurities, particularly sulfur and sulfur compounds, is 6,000 ppm or less, more preferably 3,000 ppm or less in terms of the concentration of elemental sulfur. Among these, acetylene black has a low impurity content and has a developed secondary structure structure, so that it has excellent conductivity and is particularly preferably used in the present invention.

The conductive material may be added in any amount as long as the resistance of the conductive silicone rubber composition becomes conductive, that is, the volume resistivity is 10 ¹⁴ Ω · m or less. It is preferable to set it as 1-50 mass parts with respect to 100 mass parts, especially 5-20 mass parts. If the addition amount is less than 1 part by mass, the desired conductivity may not be obtained. If the addition amount exceeds 100 parts by mass, physical mixing may be difficult or the mechanical strength may be reduced. The rubber elasticity may not be obtained.

  In addition to the above components, the silicone rubber composition of the present invention, if necessary, fumed silica, precipitated silica, fused silica, calcined silica, sol-gel spherical silica, crystalline silica (quartz powder), diatomaceous earth, etc. Silica fine particles (Note that among these silicas, especially fused silica and crystalline silica also act as other heat conductive materials), calcium carbonate, clay, diatomaceous earth, titanium dioxide reinforced, semi-reinforcing Silicone resin as a filler, reinforcing agent, nitrogen-containing compounds and acetylene compounds, phosphorus compounds, nitrile compounds, carboxylates, tin compounds, mercury compounds, sulfur compounds and other hydrosilylation reaction control agents, iron oxide, cerium oxide Such heat resistance agents, internal mold release agents such as dimethyl silicone oil, adhesion imparting agents, thixotropic properties imparting agents, etc. Optionally may be blended with no range. In addition, heat resistance improvers such as iron oxide, cerium oxide, and iron octylate, various carbon functional silanes for improving adhesion and moldability, nitrogen compounds that impart flame retardancy, and halogen compounds are added and mixed. May be. Low molecular weight siloxane having a polymerization degree of 100 or less, silanol group-containing silane, alkoxy group-containing silane, or the like may be added as a dispersion aid.

  These heat conductive inorganic powders can be mixed with components (A) and (B) at room temperature using a planetary mixer or kneader, or at a high temperature of 100 to 200 ° C. May be.

  When heat treatment is performed, for example, components (A) and (B) and a finely divided silica filler are mixed in advance to prepare a base compound, and various additives, carbon black powder and the like are similarly mixed into the kneader. It may be prepared by mixing with, or a curing agent may be added and mixed.

  The high thermal conductive silicone rubber composition thus obtained can be molded into applications that are required by various molding methods in which silicone is usually molded, such as LIM injection machines and mold pressure molding, The molding conditions are not particularly limited, but are preferably in the range of several seconds to one hour at 100 to 400 ° C. In the case of secondary vulcanization after molding, secondary vulcanization is preferably performed at 150 to 250 ° C. for 1 to 30 hours.

The fixing roll of the present invention forms a highly thermally conductive cured product layer (silicone rubber layer) of the silicone rubber composition on a core metal. In this case, the material, dimensions, and the like of the cored bar can be appropriately selected according to the type of roll, but aluminum, iron, stainless steel (SUS), or the like is used as the cored bar. The surface of these metal cores is preferably subjected to a primer treatment such as a silane coupling agent or a silicone-based adhesive for the purpose of further strengthening the adhesiveness with the silicone rubber layer.
Also, the molding and curing method of the silicone rubber composition can be appropriately selected. For example, the silicone rubber composition can be molded by a method such as injection molding, transfer molding, injection molding or coating, and cured by heating. The silicone rubber layer obtained by curing this silicone rubber composition may be formed as a single layer, for example, by laminating two or more layers having different amounts of the component (B) metal silicon powder. May be. The total thickness of the silicone rubber layer is preferably 50 μm to 20 mm, particularly preferably 0.2 mm to 6 mm. If it is too thin, sufficient rubber elasticity may not be obtained, and if it is too thick, the heat transfer characteristics between the core metal and the rubber roll surface may be impaired.
A fluororesin or fluororubber layer may be further provided on the outer periphery of the silicone rubber layer. In this case, the fluororesin or fluororubber layer is formed of a fluororesin coating material, a fluororesin tube, or the like, and covers the silicone rubber layer. Here, examples of the fluorine resin coating material include latex of polytetrafluoroethylene resin (PTFE), Daiel latex (made by Daikin Industries, Ltd., fluorine latex), etc. Commercially available products can be used, for example, polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), fluorinated ethylene-polypropylene copolymer resin (FEP), polyvinylidene fluoride resin (PVDF), polyvinyl fluoride resin and the like can be mentioned, and among these, PFA is particularly preferable.
The thickness of the fluororesin or fluororubber layer is preferably 1 μm to 500 μm, particularly preferably 10 μm to 300 μm. If it is too thin, it may break when external stress is applied to the roll, or wrinkles or peeling may occur. If it is too thick, the rubber elasticity of the roll surface may be impaired, or appearance defects such as cracks or breakage may occur. There is a case.
The fixing belt of the present invention is obtained by laminating the above silicone rubber layer on a belt base material. In this case, the belt base material can be formed of a known material such as a metal belt such as nickel electroforming, SUS, or aluminum, or an organic resin film such as polyimide resin, polyamide resin, or polyamideimide resin. Further, the shape, dimensions, and the like can be appropriately selected according to the type of belt.
The formation and curing method of the silicone rubber composition is the same as in the case of the fixing roll, and even if there is only one silicone rubber layer formed on the fixing belt substrate, the amount of the metal silicon powder of the component (B) is different from each other. Although the above plural layers may be used, the total thickness of the silicone rubber layer is preferably 50 μm to 5 mm, particularly preferably 100 μm to 1 mm. If it is too thin, rubber elasticity may not be obtained, and if it is too thick, heat transfer characteristics between the belt surface and the substrate may be impaired.
A fluororesin or a fluororubber layer can be laminated on the silicone rubber layer. In this case, the types of fluororesin and fluororubber are the same as those described for the fixing roll. The thickness of the fluororesin or fluororubber layer is preferably 1 μm to 300 μm, particularly 2 μm to 100 μm. If it is too thin, it may break when external stress is applied to the belt, or wrinkles or peeling may occur. If it is too thick, the rubber elasticity of the belt surface may be impaired, or appearance defects such as cracks or breakage may occur. There is a case.

  In addition, the cured product layer (silicone rubber layer) of this highly heat conductive silicone rubber composition has a thermal conductivity of 0.5 W / mK or more (usually 0.5 to 4.0 W / mK, particularly 0.5 to It is preferably about 2.5 W / mK).

  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. In addition, a part shows a mass part by the following example.

[Example 1]
60 parts of dimethylpolysiloxane (polymerization degree 500) blocked with dimethylvinylsiloxy groups at both ends, hydrophobized fumed silica having a specific surface area of 110 m ² / g (R-972, manufactured by Nippon Aerosil Co., Ltd.) 1 part, 2 parts of iron oxide (Fe ₂ O ₃ ) having an average particle diameter of 0.10 μm and 160 parts of pulverized metallic silicon powder A having an average particle diameter of 5 μm are put in a planetary mixer and stirred at room temperature (23 ° C.) for 2 hours. went. After the mixture was spread on three rolls to disperse the filler, it was returned to the planetary mixer again, dimethylpolysiloxane having both ends blocked with trimethylsiloxy groups and vinyl groups in the side chains (polymerization degree 300, vinyl value) 0.000075 mol / g) 40 parts, 1.0 part of methyl hydrogen polysiloxane having a Si—H group at both ends and side chains (polymerization degree 17, Si—H amount 0.0038 mol / g), reaction control As the agent, 0.05 part of ethynylcyclohexanol and 0.1 part of platinum catalyst (Pt concentration 1% by mass) were added, and the resulting composition was continuously stirred for 15 minutes to obtain a silicone rubber composition (actual-1).
This silicone rubber composition (Ex. 1) was press-cured at 120 ° C. for 10 minutes, further oven-cured at 200 ° C. for 4 hours, and then the hardness and compression set after 180 ° C./22 hours according to JIS K6249. After measuring the thermal conductivity of a sheet having a thickness of 12 mm, the thermal conductivity was measured with a thermal conductivity meter (QTM-3, manufactured by Kyoto Electronics Co., Ltd.).
Further, after leaving this sample in an oven at 230 ° C. for 144 hours, the hardness was measured and the degree of deterioration was confirmed.

[Example 2]
A sample was prepared using a silicone rubber composition (act-2) prepared in the same manner as in Example 1 except that 250 parts of ground metal silicon powder B having an average particle diameter of 12 μm was blended instead of 60 parts of ground metal silicon powder Al. Prepared and obtained data.

[Example 3]
A silicone rubber composition prepared in the same manner as in Example 1 except that, in place of 160 parts of pulverized metal silicon powder A, 20 parts of pulverized metal silicon powder Bl having an average particle diameter of 12 μm and 90 parts of spherical alumina having an average particle diameter of 12 μm were blended. A sample was prepared using the object (act-3), and data was obtained.

[Example 4]
Instead of pulverized metallic silicon powder A160 parts, a sample was prepared using a silicone rubber composition (Ex.-4) prepared in the same manner as in Example 1 except that 260 parts of spherical metallic silicon powder having an average particle size of 5 μm was blended. Prepared and obtained data.

[Example 5]
Viscosity consisting of 99.825 mol% of dimethylsiloxane units and 0.15 mol% of methylvinylsiloxane units and having both ends of the molecular chain blocked with 0.025 mol% of dimethylvinylsilyl groups is 1 × 10 ⁷ mm ² / s 100 parts of organopolysiloxane, 12 parts of acetylene black, Denka black (average particle diameter 40 nm, trade name, manufactured by Electrochemical Co., Ltd.) and fumed silica (specifically Nippon Aerosil Co., Ltd.) having a specific surface area of 200 m ² / g 3 parts, 2 parts of silanol dimethylpolysiloxane polymer having both ends of an average degree of polymerization of 3 to 10 as a dispersing agent, and 155 parts of pulverized metal silicon powder A155 having an average particle diameter of 5 μm as a thermal conductivity imparting filler are kneaded using a pressure kneader. After that, 2,5-dimethyl-bis- (2,5-t-butyl) is used as a curing agent with respect to 100 parts of the base compound. Peroxy) hexane 25% silicone paste 2 parts was added to prepare a silicone rubber composition.
This silicone rubber composition (Ex. 5) was press-cured at 165 ° C. for 10 minutes, and further oven-cured at 200 ° C. for 4 hours. Then, the hardness and 180 ° C./22 were measured according to JIS K6249 as in Example 1. The compression set after the time, thermal conductivity, and volume resistivity were measured. Further, after leaving this sample in an oven at 230 ° C. for 144 hours, the hardness was measured and the degree of deterioration was confirmed.

[Comparative Example 1]
An attempt was made to mix 250 parts of quartz powder having the same composition as in Example 1 and an average particle size of 5 μm in place of 160 parts of pulverized metal silicon powder A so that the thermal conductivity equivalent to that of Example 1 was obtained. It could not be blended.

[Comparative Example 2]
A sample was prepared and data was obtained in the same manner as in Example 1 except that 260 parts of granular alumina powder having an average particle diameter of 5 μm was blended instead of 160 parts of pulverized metal silicon powder A.

[Comparative Example 3]
A sample was prepared and data was obtained in the same manner as in Example 2 except that 500 parts of spherical alumina powder having an average particle diameter of 12 μm was blended in place of 250 parts of pulverized metal silicon powder B in Example 2.

[Comparative Example 4]
A sample was prepared and data was obtained in the same manner as in Example 1 except that 320 parts of spherical alumina powder having an average particle diameter of 16 μm was blended in place of 160 parts of pulverized metal silicon powder A in Example 1.

[Comparative Example 5]
A sample was prepared and data was obtained in the same manner as in Example 1 except that 280 parts of spherical aluminum powder having an average particle diameter of 5 μm was blended in place of 160 parts of pulverized metal silicon powder A in Example 1.

[Example 6]
Primer No. for addition reaction type liquid silicone rubber on the surface of an aluminum shaft having a diameter of 12 mm and a length of 300 mm. 101 A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied. This aluminum shaft was fixed in a mold, and the silicone rubber composition (Example-1) of Example 1 was filled in the mold at a pressure of 10 kgf / cm ² , heated and cured at 150 ° C. for 30 minutes, and further 200 Post-curing was performed at 4 ° C. for 4 hours to obtain a silicone rubber roll (outer diameter: 16 mm) having a silicone rubber layer thickness of 2 mm. This fixing roll was mounted on an electrophotographic copying machine, and 50,000 copies of A4 size copying paper were continuously copied. However, there were no paper wrinkles or paper jams, and all the copied images were clear.

[Comparative Example 6]
A roll was prepared in the same manner as in Example 6 except that the silicone rubber composition of Comparative Example 2 was used instead of the silicone rubber composition of Example 1 (Ex. 1), and mounted on an electronic copying machine to be A4 size. As a result, the image became unclear from the 25,000th sheet. When the roll was confirmed, it was confirmed that the silicone rubber layer was broken and the roll was broken.

[Example 7]
Primer No. for addition reaction type liquid silicone rubber on the surface of an aluminum shaft having a diameter of 12 mm and a length of 300 mm. 101 A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied. Between the 50 μm fluorine PFA tube whose inner surface was primed and the aluminum shaft, the silicone rubber composition (Example-2) of Example 2 was filled at a pressure of 5 kgf / cm ² and heated and cured at 150 ° C. for 30 minutes. Further, the film was post-cured at 200 ° C. for 4 hours to prepare a PFA resin-coated silicone rubber roll having an outer diameter of 20 mm × a length of 250 mm. This fixing roll was mounted on an electrophotographic copying machine, and 50,000 sheets of A4 size copying paper were continuously copied. However, there were no paper wrinkles or paper jams, and all the copied images were clear.

[Comparative Example 7]
A roll was prepared in the same manner as in Example 7 except that the silicone rubber composition of Comparative Example 3 was used instead of the silicone rubber composition (Act-2), and the A4 size copy paper was mounted on an electronic copying machine. When the paper was continuously fed, the image became unclear from the 30,000th sheet. When the roll was confirmed, it was confirmed that the shape was deformed at the end.

[Example 8]
Primer No. for addition reaction type liquid silicone rubber was formed on the outer peripheral surface of a nickel belt base material (thickness 50 μm, shape: inner diameter φ55 mm, width 250 mm). 101 A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied, dried, and baked (150 ° C. × 15 minutes). On top of this, the silicone rubber composition (Example-1) of Example 1 was coated (thickness: about 300 μm), heated at 150 ° C. for 15 minutes, and further post-cured at 200 ° C. for 2 hours. Dairy latex and silicone rubber primer GLP-103SR (manufactured by Daikin) are uniformly applied to the surface of the cured product, heated at 80 ° C. for 10 minutes, and further, Daiel latex GLS-213 is uniformly applied by spraying. A fixing belt made of fluororesin-coated silicone rubber having a fluororesin layer thickness of 5 μm was prepared by heating and baking at 0 ° C. for 1 hour. This fixing belt was mounted on an electrophotographic copying machine, and 50,000 sheets of A4 size copying paper were continuously copied. However, there were no paper wrinkles or paper jams, and all the copied images were clear.

[Comparative Example 8]
A fixing belt was prepared in the same manner as in Example 8 except that the silicone rubber composition of Comparative Example 2 was used instead of the silicone rubber composition (Ex. 1), and the fixing belt was mounted on an electronic copying machine. When the paper was continuously fed, the image became unclear from the 10,000th sheet, paper wrinkles were generated from the 12,000th sheet, and the experiment was stopped.

  From the above results, the silicone rubber composition (Example) of the present invention has excellent thermal conductivity and heat resistance, low compression set, and excellent characteristics as a high thermal conductive silicone rubber for fixing rolls and fixing belts. It can be seen that

Claims (9)

A fixing roll in which at least one silicone rubber layer is formed on the outer peripheral surface of the roll shaft, and the silicone rubber forming the silicone rubber layer includes:
(A) 100 parts by mass of an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) Metallic silicon powder having an average particle size of 100 μm or less 20 to 500 parts by mass (C) What is obtained by curing a highly thermally conductive silicone rubber composition containing a curing agent in an amount capable of curing the component (A). A heat-fixing roll characterized by A fixing roll in which a fluororesin layer or a fluororubber layer is formed on the outer peripheral surface of a roll shaft via at least one silicone rubber layer, and the silicone rubber forming the silicone rubber layer includes:
(A) 100 parts by mass of an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) Metallic silicon powder having an average particle size of 100 μm or less 20 to 500 parts by mass (C) What is obtained by curing a highly thermally conductive silicone rubber composition containing a curing agent in an amount capable of curing the component (A). A heat-fixing roll characterized by The heat fixing roll according to claim 1 or 2 , wherein the metal silicon powder of the component (B) in the silicone rubber composition is pulverized metal silicon powder having a mean particle size of 1 to 50 µm by pulverization. The heat fixing roll according to claim 1 or 2 , wherein the metal silicon powder as the component (B) in the silicone rubber composition is a spherical metal silicon powder having an average particle diameter of 1 to 50 µm. The heat fixing roll according to any one of claims 1 to 4 , wherein the silicone rubber layer has a thermal conductivity of 0.5 W / mK or more. A fixing belt having at least one silicone rubber layer on a belt base material, and having a fluororesin layer or a fluororubber layer formed thereon if necessary, wherein the silicone rubber forming the silicone rubber layer comprises:
(A) 100 parts by mass of an organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule;
(B) Metallic silicon powder having an average particle size of 100 μm or less 20 to 500 parts by mass (C) What is obtained by curing a highly thermally conductive silicone rubber composition containing a curing agent in an amount capable of curing the component (A). A fixing belt characterized by being. The fixing belt according to claim 6 , wherein the metal silicon powder of component (B) in the silicone rubber composition is pulverized metal silicon powder having a mean particle size of 1 to 50 μm, which is pulverized by a pulverization method. The fixing belt according to claim 6 , wherein the metal silicon powder of the component (B) in the silicone rubber composition is a spherical metal silicon powder having an average particle diameter of 1 to 50 μm. The thermal conductivity of the silicone rubber layer, the fixing belt of any one of claims 6 to 8 is 0.5 W / mK or more.