JP5471350B2 - High heat conductive silicone rubber composition for fixing roll for office machine or fixing belt for office machine, fixing roll and fixing belt - Google Patents

Description

  The present invention provides a thermally conductive silicone rubber composition containing a high filling amount of thermally conductive powder, which improves the interfacial crosslinkability between the thermally conductive filler and the silicone polymer and is used as a fixing roll or a fixing belt for office machines. The present invention relates to a rubber composition that is hard to break rubber, that is, for the purpose of improving durability of rolls and belts. Specifically, it relates to improvement of durability of fixing rolls and fixing belts (preventing rubber breakage of rolls and belts) using a high thermal conductive silicone rubber composition containing heat conductive powders of alumina, metal silicon, silicon carbide, etc. It is.

  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 by conventional fluororesin processing of metal or metal surface. Many types are coated with fluororesin. 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, heat resistance 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.

  Examples of such silicone rubber include JP-A-58-219259 (alumina compound), JP-A-3-221982 (magnesium oxide compound), JP-A-2003-208052 (silicon carbide compound), JP-A-2007. No. 171946 (metal silicon blend): those proposed in Patent Documents 1 to 4 have been used. These are those in which a thermally conductive filler is blended in conventionally used silicone rubber. However, in order to improve the thermal conductivity, it is necessary to add a large amount of fillers. As a result, the rubber strength and rubber compression required for rubber rolls and belts are reduced, the rubber compression set is deteriorated, and the heat resistance is reduced. As a result, the rubber is easily broken during use as a copying machine or printer, and the durability of rolls and belts is reduced.

JP 58-219259 A JP-A-3-221982 JP 2003-208052 A JP 2007-171946 A JP 2000-256558 A JP 2001-139815 A JP 2003-213133 A JP-A-6-95545

  The present invention has been made in view of the above circumstances, and in a silicone rubber composition having high thermal conductivity, that is, a highly filled filler, improved interfacial crosslinking between the polymer and the high thermal conductive powder, and has excellent durability. It is an object of the present invention to provide a heat fixing roll, a fixing roll for an office machine that enables a fixing belt, or a high thermal conductive silicone rubber composition for a fixing belt, and a fixing roll and a fixing belt.

  As a result of examining various factors that contribute to the improvement of heat resistance of rolls and belts in the high-filling silicone rubber composition of the heat conductive filler, the present inventors have determined the interface affinity between the silicone polymer and the heat conductive filler. In order to improve, by adding a component having a structure having incompatible H siloxane (siloxane having SiH group) in the main silicone polymer, the component is easily collected around the thermally conductive powder, By heating and curing the composition, it is possible to intentionally increase the cross-linking efficiency of the polymer around the thermally conductive powder, thereby preventing rubber breakage around the thermally conductive powder and improving roll and belt durability. It has been found that it is useful as a rubber layer for fixing rolls and fixing belts of various copying machines and printers, and has led to the present invention. It is.

  In the high thermal conductive silicone rubber composition, an organopolysiloxane having a silicon atom-bonded hydrolyzable group is used as a surface treatment agent in order to stably add a large amount of a thermal conductive filler. No. 256558 and JP-A-2001-139815 (Patent Documents 5 and 6) have been reported, but cannot be a preventive measure for rubber breakage generated from the interface between the filler and the polymer. It is a method of breaking hydrogen bonds between fillers and does not improve the durability of rolls and belts. Furthermore, in Japanese Patent Application Laid-Open No. 2003-213133 (Patent Document 7), an organopolysiloxane having a vinyl group and a silicon atom-bonded hydrolyzable group is used as a surface treatment agent for a thermally conductive filler. Although a method for introducing a group has been described, a large amount of vinyl groups is introduced on the powder surface, so that the material does not have a low rubber hardness, and the elongation physical properties are also reduced, so that the rubber is easily broken. There is.

  Japanese Patent Application Laid-Open No. 6-95545 (Patent Document 8) proposes a method in which a silane coupling agent having a (meth) acryloxy group is added for the purpose of improving the adhesion to a fluororesin. There is no mention of the adhesive effect on the adhesive filler, and it does not propose the effect of preventing the rubber component of the fixing roll or fixing belt from being destroyed.

（ｂ）一分子中に少なくとも１個の珪素原子に結合した水素原子を有し、かつ下記一般式（４）又は（５）で示される一価又は二価の芳香環含有有機基を有する有機化合物

［但し、式中Ｒ⁴〜Ｒ¹²はそれぞれ水素原子、ハロゲン原子、非置換もしくはハロゲン置換の一価炭化水素基、又はアルコキシ基であり、Ｘは下記の基から選ばれる基である。

（Ｒ¹³、Ｒ¹⁴はそれぞれ非置換又はハロゲン置換の一価炭化水素基である。）］
（Ｄ）平均粒子径が０．５〜５０μｍの熱伝導性粉末：８０〜２，０００質量部、及び
（Ｅ）白金又は白金系化合物：触媒量
を配合してなることを特徴とする事務機用定着ロール又は事務機用定着ベルト用高熱伝導性シリコーンゴム組成物。
〔請求項２〕
熱伝導性粉末が、アルミナ、金属珪素及び炭化珪素から選択される少なくとも一種であり、付加硬化型シリコーンゴム組成物が、熱伝導率０．５Ｗ／ｍ・ｋ以上の硬化物を与えるものである請求項１記載のシリコーンゴム組成物。
〔請求項３〕
芯金の外周面にシリコーンゴム層が形成されてなる定着ロールにおいて、シリコーンゴム層が請求項１又は２記載のシリコーンゴム組成物の硬化物であることを特徴とする定着ロール。
〔請求項４〕
芯金の外周面にシリコーンゴム層を介してフッ素系樹脂層が形成されてなる定着ロールにおいて、シリコーンゴム層が請求項１又は２記載のシリコーンゴム組成物の硬化物であることを特徴とするフッ素系樹脂被覆定着ロール。
〔請求項５〕
耐熱性樹脂又は金属からなる基板の表裏いずれかの面上にシリコーンゴム層が形成されてなる定着ベルトにおいて、シリコーンゴム層が請求項１又は２記載のシリコーンゴム組成物の硬化物であることを特徴とする定着ベルト。
〔請求項６〕
耐熱性樹脂又は金属からなる基板の表裏いずれかの面上にシリコーンゴム層を介してフッ素系樹脂層が形成されてなる定着ベルトにおいて、シリコーンゴム層が請求項１又は２記載のシリコーンゴム組成物の硬化物であることを特徴とするフッ素系樹脂被覆定着ベルト。 Accordingly, the present invention provides the following highly heat conductive silicone rubber composition for office machine fixing rolls or office machine fixing belts, as well as fixing rolls and fixing belts.
[Claim 1]
(A) The following average composition formula (1)
R ¹ _a SiO _{(4-a) / 2} (1)
(In the formula, R ¹ is the same or different unsubstituted or halogen-substituted monovalent hydrocarbon group, and a is a positive number of 1.8 ≦ a ≦ 2.205.)
Diorganopolysiloxane having a viscosity of 100 to 10,000,000 mPa · s at 25 ° C. having at least two aliphatic unsaturated groups in one molecule:
(B) The following average composition formula (2)
R ² _b H _c SiO _{(4-bc) / 2} (2)
Wherein R ² is the same or different unsubstituted or halogen-substituted monovalent aliphatic saturated hydrocarbon group, and b and c are 0.8 ≦ b ≦ 2.2 and 0.002 ≦ c ≦, respectively. 1.0 and a positive number satisfying 0.802 ≦ b + c ≦ 3.0.)
An organohydrogenpolysiloxane having a hydrogen atom bonded to at least three silicon atoms in one molecule: 0 to 20 parts by mass,
(C) Compound selected from the following (a) and (b): 0.01 to 5 parts by mass,
(A) The following average composition formula (3)
Q _d R ³ _e H _f SiZ _{(4-def) / 2} (3)
Wherein Q is a monovalent organic group having one or more aromatic rings, R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group, and Z is selected from an oxygen atom or a divalent hydrocarbon group. And at least one is an oxygen atom, d, e, and f are 0 <d ≦ 2, 0 ≦ e ≦ 2, 0 <f ≦ 1, 0.8 ≦ d + e + f ≦ 3.0, respectively. (It is a positive number.)
The content of a monovalent organic group having a hydrogen atom bonded to at least two silicon atoms in one molecule and having an aromatic ring among the monovalent organic groups bonded to the silicon atom is 12 mol%. An organohydrogenpolysiloxane having a monovalent group selected from at least one group represented by the following formula in one molecule

(B) Organic having a hydrogen atom bonded to at least one silicon atom in one molecule and a monovalent or divalent aromatic ring-containing organic group represented by the following general formula (4) or (5) Compound

[Wherein, R ^{4 to} R ¹² are each a hydrogen atom, a halogen atom, an unsubstituted or halogen-substituted monovalent hydrocarbon group, or an alkoxy group, and X is a group selected from the following groups.

(R ¹³ and R ¹⁴ are each an unsubstituted or halogen-substituted monovalent hydrocarbon group.)]
(D) Thermally conductive powder having an average particle size of 0.5 to 50 μm: 80 to 2,000 parts by mass, and (E) platinum or a platinum-based compound: a catalytic amount, and an office machine characterized by comprising High heat conductive silicone rubber composition for fixing roll for office use or fixing belt for office machine .
[Claim 2]
The heat conductive powder is at least one selected from alumina, metal silicon and silicon carbide, and the addition curable silicone rubber composition gives a cured product having a thermal conductivity of 0.5 W / m · k or more. The silicone rubber composition according to claim 1.
[Claim 3]
A fixing roll having a silicone rubber layer formed on the outer peripheral surface of a core metal, wherein the silicone rubber layer is a cured product of the silicone rubber composition according to claim 1 or 2.
[Claim 4]
In the fixing roll in which a fluororesin layer is formed on the outer peripheral surface of the metal core via a silicone rubber layer, the silicone rubber layer is a cured product of the silicone rubber composition according to claim 1 or 2. Fluorine resin-coated fixing roll.
[Claim 5]
In the fixing belt in which a silicone rubber layer is formed on either the front or back surface of a substrate made of a heat resistant resin or metal, the silicone rubber layer is a cured product of the silicone rubber composition according to claim 1 or 2. Features a fixing belt.
[Claim 6]
The silicone rubber composition according to claim 1 or 2, wherein the silicone rubber layer is a fixing belt in which a fluorine-based resin layer is formed on either the front or back surface of a substrate made of a heat resistant resin or metal via a silicone rubber layer. A fluororesin-coated fixing belt, which is a cured product of

  According to the present invention, the incompatible H siloxane of component (C) is likely to gather around the thermally conductive filler of component (D), so that the crosslinking efficiency of the main polymer of component (A) at the filler interface is unique. The durability of the fixing roll for office machines and the fixing belt can be improved by preventing fatigue breakage between the filler and the rubber, which is likely to occur from the powder interface in the highly filled material of the high thermal conductive powder.

  According to the highly thermally conductive silicone rubber composition of the present invention, the interface affinity between the main polymer and the thermally conductive powder is improved, and the crosslinking density around the thermally conductive powder is increased, so that the rubber breakage near the filler interface is prevented. It is possible to provide a highly heat-conductive fixing roll or fixing belt excellent in durability and durability. By using the fixing roll and the fixing belt of the present invention, it is possible to reduce the risk of failure and stoppage of the copying machine and the printer due to the destruction of the heat fixing roll or the fixing belt.

Hereinafter, the present invention will be described in more detail.
The (A) component of the silicone rubber composition of the present invention has the following average composition formula (1)
R ¹ _a SiO _{(4-a) / 2} (1)
(In the formula, R ¹ is the same or different unsubstituted or halogen-substituted monovalent hydrocarbon group, and a is a positive number of 1.8 ≦ a ≦ 2.205.)
This is a diorganopolysiloxane having at least two aliphatic unsaturated groups in one molecule, and this component is a known organopolysiloxane usually used as a main raw material for addition-curable silicone rubber compositions. is there.

Here, R ¹ in the above formula is preferably an aliphatic unsaturated group such as an alkenyl group such as a vinyl group having 2 to 8 carbon atoms, an allyl group, a propenyl group or a butenyl group, or a methyl group having 1 to 10 carbon atoms. Alkyl groups such as ethyl group, propyl group, butyl group, hexyl group, cyclohexyl group and octyl group, aryl groups such as phenyl group and tolyl group, aralkyl groups such as benzyl group and phenylethyl group, etc. Examples thereof include a 3,3,3-trifluoropropyl group and a chloromethyl group in which part or all of the hydrogen atoms bonded to the carbon atom are substituted with a halogen atom. Each substituent R ¹ may be different or the same.

The organopolysiloxane of the above formula (1) needs to have at least two aliphatic unsaturated groups. As the aliphatic unsaturated groups, alkenyl groups such as vinyl groups and allyl groups are particularly preferable. As other substituents, a methyl group and a phenyl group are particularly desirable. The content of aliphatic unsaturated groups in R ¹ is 0.001 to 20 mol% of the total substituents R ^1, is preferably in particular 0.025 mol%. The aliphatic unsaturated group may be bonded to a silicon atom at the end of the molecular chain or may be bonded to a silicon atom in the middle of the molecular chain.
Further, a is a positive number of 1.8 ≦ a ≦ 2.205 as described above, and more preferably 1.9 ≦ a ≦ 2.2.

The organopolysiloxane of the above formula (1) may be linear or branched containing R ¹ SiO _3/2 units or SiO _4/2 units. The chain is preferably a linear diorganopolysiloxane composed of repeating diorganosiloxane units and having both ends of the molecular chain blocked with triorganosiloxy groups, and the average degree of polymerization is 100 to 10,000, particularly 200. It is preferable that the viscosity is in the range of ˜5,000, and the viscosity at 25 ° C. is in the range of 100 to 10,000,000 mPa · s, preferably 600 to 200,000 mPa · s.
The degree of polymerization (or the number of silicon atoms in the molecule) can be determined as a number average value in terms of polystyrene by GPC (gel permeation chromatography) analysis, and the viscosity can be measured with a rotational viscometer ( same as below).

  Such a diorganopolysiloxane can be produced by a known method. For example, it can be obtained by conducting an equilibration polymerization reaction of organocyclopolysiloxane and hexaorganodisiloxane in the presence of an alkali or an acid catalyst. it can.

Next, the organohydrogenpolysiloxane as the component (B) optionally used as necessary can act as a cross-linking agent, and the following average composition formula (2)
R ² _b H _c SiO _{(4-bc) / 2} (2)
Wherein R ² is the same or different unsubstituted or halogen-substituted monovalent aliphatic saturated hydrocarbon group, and b and c are 0.8 ≦ b ≦ 2.2 and 0.002 ≦ c ≦, respectively. 1.0 and a positive number satisfying 0.802 ≦ b + c ≦ 3.0.)
And having hydrogen atoms bonded to at least three silicon atoms in one molecule.

Here, R ² in the above formula (2) is the same or different unsubstituted or halogen-substituted monovalent aliphatic saturated hydrocarbon group, specifically, alkyl in R ¹ in the above formula (1). Examples thereof include the same groups as the group and the halogen-substituted alkyl group. Further, b and c are positive numbers as described above, but more preferably are positive numbers satisfying 1 ≦ b ≦ 2, 0.01 ≦ c ≦ 0.5, and 1.01 ≦ b + c ≦ 2.5. .

  The organohydrogenpolysiloxane of the above formula (2) is not particularly limited in its molecular structure, and various types such as linear, branched, cyclic, and three-dimensional network structures can be used. The average degree of polymerization (or the number of silicon atoms in the molecule) is preferably 300 or less (usually 3 to 300), particularly 4 to 200, more preferably about 4 to 100, and a viscosity at 25 ° C. of 0.5 to 5, 000 mPa · s, particularly preferably in the range of 1 to 3,000 mPa · s. Further, the number of silicon atom-bonded hydrogen atoms (that is, hydrosilyl group represented by SiH) in one molecule is usually 3 to 300, preferably 4 to 200, more preferably about 4 to 100. Good. In particular, branched tris (dimethylhydrogensiloxy) silyl group and cyclic 1,3,5,7-tetramethylcyclo which are essential contained in the organohydrogenpolysiloxane of component (C) (a) described later. It is preferably an organohydrogenpolysiloxane having a linear structure or a three-dimensional network structure that does not contain a tetrasiloxy group.

  Such an organohydrogenpolysiloxane of the above formula (2) can be produced by a known method, for example, a compound selected from octamethylcyclotetrasiloxane and 1,3,5,7-tetramethylcyclotetrasiloxane. And a compound containing hexamethyldisiloxane or 1,1,3,3-tetramethyldisiloxane unit which can be a terminal group in the presence of a catalyst such as sulfuric acid, trifluoromethanesulfonic acid, methanesulfonic acid, etc. It can be easily obtained by equilibrating at a certain temperature.

Specific examples of the organohydrogenpolysiloxane of the above formula (2) include, for example, both terminal trimethylsiloxy group-capped methylhydrogen polysiloxane, both terminal trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, both terminal Dimethylhydrogensiloxy-blocked dimethylpolysiloxane, both ends dimethylhydrogensiloxy-blocked methylhydrogenpolysiloxane, both ends dimethylhydrogensiloxy-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, (CH ₃ ) ₂ HSiO _{1 / 2} unit, copolymer composed of (CH ₃ ) ₃ SiO _1/2 unit and SiO _4/2 unit, copolymer composed of (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit, etc. Is mentioned.

  The blending amount of the organohydrogenpolysiloxane of the component (B) is preferably 0 to 20 parts by mass, more preferably 0.1 to 10 parts per 100 parts by mass of the diorganopolysiloxane of the component (A). Part by mass. When the blending amount of the component (B) is within this range, the composition can be easily cured into a rubbery shape, and particularly the rubber hardness after cross-linking is within a suitable range (for example, 1 to 90 for durometer type A). This is preferable because the degree of freedom for setting increases.

  In this invention, the compound selected from the following (a) and (b) component is mix | blended as (C) component. By adding this component (C), even if a large amount of the heat conductive powder blended in the composition of the present invention is blended, the crosslink density around the heat conductive powder can be raised specifically, It can be set as the composition excellent in roll durability.

(A) The following average composition formula (3)
Q _d R ³ _e H _f SiZ _{(4-def) / 2} (3)
Wherein Q is a monovalent organic group having one or more aromatic rings, R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group, and Z is selected from an oxygen atom or a divalent hydrocarbon group. And at least one is an oxygen atom, d, e, and f are 0 <d ≦ 2, 0 ≦ e ≦ 2, 0 <f ≦ 1, 0.8 ≦ d + e + f ≦ 3.0, respectively. (It is a positive number.)
A monovalent organic compound having a hydrogen atom bonded to at least two silicon atoms in one molecule and an aromatic ring among the monovalent organic groups bonded to the silicon atom (that is, Q and R ³ ) The group content is 12 mol% or more, and is selected from the groups represented by the following formulas (i) to (iii) of at least 1, preferably 1 to 6, more preferably 2 to 4 in one molecule. Organohydrogenpolysiloxane having a monovalent group.

  (B) Organic having a hydrogen atom bonded to at least one silicon atom in one molecule and a monovalent or divalent aromatic ring-containing organic group represented by the following general formula (4) or (5) Compound.

［但し、式中Ｒ⁴〜Ｒ¹²はそれぞれ水素原子、ハロゲン原子、非置換もしくはハロゲン置換の一価炭化水素基、又はアルコキシ基であり、Ｘは下記の基から選ばれる基である。

（Ｒ¹³、Ｒ¹⁴はそれぞれ非置換又はハロゲン置換の一価炭化水素基である。）］

[Wherein, R ^{4 to} R ¹² are each a hydrogen atom, a halogen atom, an unsubstituted or halogen-substituted monovalent hydrocarbon group, or an alkoxy group, and X is a group selected from the following groups.

(R ¹³ and R ¹⁴ are each an unsubstituted or halogen-substituted monovalent hydrocarbon group.)]

  In the formula (3) of the component (a), Q is a monovalent organic group having one or more aromatic rings, preferably 1 to 3 aromatic rings. If the monovalent organic group represented by Q has more than 3 aromatic rings, the compatibility with siloxane may be lost or the elongation of rubber properties may be lost. Specific examples of the substituent Q include the following groups.

（但し、Ｒは前記したＲ¹と同様の非置換又はハロゲン置換の一価炭化水素基、Ｒ’は水素原子又は前記Ｒ¹と同様の非置換もしくはハロゲン置換の一価炭化水素基である。）

(Wherein, R represents the same unsubstituted or halogen-substituted monovalent hydrocarbon group as R ¹ described above, R 'is hydrogen atom or a similar non-substituted or halogen-substituted monovalent hydrocarbon group and the R ^1. )

R ³ in the formula (3) is an unsubstituted or halogen-substituted monovalent hydrocarbon group, particularly an unsubstituted or halogen-substituted monovalent aliphatic hydrocarbon group excluding an aromatic hydrocarbon group, preferably carbon. Aliphatic unsaturated groups such as vinyl groups, allyl groups, propenyl groups and butenyl groups having 2 to 8 carbon atoms, methyl groups having 1 to 10 carbon atoms, ethyl groups, propyl groups, butyl groups, hexyl groups, cyclohexyl groups and octyl groups Alkyl groups such as chloromethyl group, 3,3,3-trifluoropropyl group, C ₄ F ₉ CH ₂ CH ₂ —, C ₈ F in which some or all of the hydrogen atoms are substituted with halogen atoms ₁₇ CH ₂ CH ₂ — and the like.

Z is a group selected from an oxygen atom or a divalent hydrocarbon group, at least one of which is an oxygen atom. As this divalent hydrocarbon group, those having 2 to 8 carbon atoms are preferably used, and examples thereof include alkylene groups such as ethylene group, propylene group, tetramethylene group, hexamethylene group and methylethylene group.
d, e, and f are 0 or a positive number satisfying 0 <d ≦ 2, 0 ≦ e ≦ 2, 0 <f ≦ 1, 0.8 ≦ d + e + f ≦ 3.0, respectively.

  The organohydrogenpolysiloxane of the above formula (3) has at least 2, preferably 3 to 50, more preferably 4 to 20 silicon atoms directly bonded to one silicon atom in one molecule. The content of the monovalent organic group having an aromatic ring among the monovalent organic groups bonded to the silicon atom in the molecule is 12 mol% or more, preferably 15 to 80 mol%, more preferably 20 It must be ˜60 mol%. If the content is less than 12 mol%, satisfactory adhesiveness cannot be obtained.

  In addition, when the organohydrogenpolysiloxane having three or more functionalities represented by the average composition formula (2) which is the component (B) is not blended in the composition of the present invention, the above formula (3) as the component (C) A hydrogen atom bonded to a silicon atom in one molecule in any one or each of the organohydrogenpolysiloxane (a) represented by formula (a) and the compound (b) having a group represented by the following general formula (4) or (5) The number of (SiH groups) is appropriately selected so that the total with the number of aliphatic unsaturated groups in one molecule in component (A) is 5 or more. That is, when (B) component is not blended and (A) component is a difunctional diorganopolysiloxane (diorganopolysiloxane having two aliphatic unsaturated groups in one molecule), (C) Silicone rubber can be satisfactorily selected by selecting one or both of the compound (a) and the compound (b) as the component to be trifunctional or more (3 or more SiH groups in one molecule). A cured product can be obtained.

  The organohydrogenpolysiloxane of the above formula (3) is not particularly limited in its molecular structure, and various structures such as linear, cyclic and branched structures can be used. The range is preferably 1,000,000 mPa · s.

  The organohydrogenpolysiloxane (a) of the formula (3) is not limited to this, but the following can be exemplified.

（但し、Ｒは前記したＲ¹と同様の非置換又はハロゲン置換の一価炭化水素基、Ｒ’は水素原子又は前記Ｒ¹と同様の非置換又はハロゲン置換の一価炭化水素基であり、Ｙは下記式

で示されるものから選ばれる一価の基である。）

(Wherein, R represents the same unsubstituted or halogen-substituted monovalent hydrocarbon group as R ¹ described above, R 'is hydrogen atom or a similar non-substituted or halogen-substituted monovalent hydrocarbon group and the R ^1, Y is the following formula

Is a monovalent group selected from those represented by the formula: )

On the other hand, the monovalent or divalent aromatic ring-containing organic group represented by the above formula (4) or (5) having a hydrogen atom bonded to at least one silicon atom in one molecule of the component (b) In the organic compound having R ^{4 to} R ¹² , R ¹³ , R ¹⁴ , and the unsubstituted or halogen-substituted monovalent hydrocarbon group bonded to the silicon atom contained in other molecules, the above-mentioned (A) include the same number of carbon 10 as that described in R ¹ in the component, and as the alkoxy group in R ⁴ to R ^12, a methoxy group, an ethoxy group, a propoxy group, 1 to 4 carbon atoms, such as butoxy -10, preferably 1-6, and halogen atoms include fluorine, chlorine, iodine and the like.

  In addition, as this compound (b), the number average molecular weight of polystyrene conversion in a gel permeation chromatography (GPC) is 400-100,000, Especially the thing of 400-50,000 is preferable, Moreover, it is a silicon atom in one molecule. The number of bonded hydrogen atoms (SiH group) is more preferably 2 or more, still more preferably 3 or more, particularly 3 to 50, especially 4 to 20, and the number of silicon atoms in one molecule is 3 to 100, In particular, it is preferably 5 to 50. Further, this compound preferably has the following group as a group containing such a SiH group.

（但し、Ｒ¹⁵は水素原子又は炭素数１〜８の非置換もしくはハロゲン置換の一価炭化水素基を示す。ｎは１〜３である。）

(However, R ¹⁵ is .n represents a hydrogen atom or an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 8 carbon atoms is 1-3.)

Among the above groups, examples of the unsubstituted or halogen-substituted monovalent hydrocarbon group for R ¹⁵ include those having 1 to 8 carbon atoms similar to those described for R ¹ in the component (A).
Specific examples of such compounds include the following organohydrogenpolysiloxane compounds.

  In this invention, the compounding quantity of (C) component is the range of 0.01-5 mass parts with respect to 100 mass parts of diorganopolysiloxane of (A) component, and the range of 0.05-3 mass parts is preferable. When the amount is less than 0.01 parts by mass, the crosslinking effect that can withstand practical use is inferior. When the amount is more than 5 parts by mass, the elongation at break of rubber becomes small, the rubber is easily cracked and torn, and physical properties are impaired.

  In this case, the total of hydrogen atoms (SiH groups) bonded to silicon atoms in the (B) component organohydrogenpolysiloxane and (C) component for one aliphatic unsaturated group contained in the entire composition. A range of 0.3 to 10, particularly 0.5 to 5 is preferable. In this case, the number of SiH groups in the component (C) is preferably 0.5 to 100%, particularly 5 to 75% of the total SiH groups in the components (B) and (C). If the amount added is less than the above value, curing may be insufficient, or even if cured, the physical properties of the cured product may be inferior. In some cases, the physical properties of the cured product may change over time.

  The component (D) is a thermally conductive powder for imparting thermal conductivity to the composition of the present invention, and the thermal conductivity of the silicone rubber composition of the present invention is blended with the thermally conductive powder (D). Can be obtained.

  Known materials can be used as the heat conductive powder and are not particularly limited. Specifically, crystalline silica, alumina, aluminum, silicon carbide, silicon nitride, metal silicon, magnesium oxide, magnesium carbonate Zinc oxide, aluminum nitride, graphite, fibrous graphite and the like.

  Among the above heat conductive powders, it is particularly preferable to use alumina, metal silicon, or silicon carbide. The selection of the heat conductive powder is appropriately selected according to the hardness, heat resistance, rubber compression set required for the rubber roll or belt, and the filling amount of the filler. Alumina is suitable because it is easy to obtain a spherical powder and easily increase the filling rate. Metallic silicon is preferable because it hardly precipitates and has excellent heat resistance, and silicon carbide is particularly suitable because it has good thermal conductivity and polymer compoundability.

  The shape of the heat conductive powder used in the present invention is not particularly limited, and heat conductive powders having various shapes such as a spherical shape, a pulverized shape, a fiber shape, and a needle shape can be used.

The average particle diameter of the heat conductive powder used in the present invention is 0.5 to 50 μm or less, preferably 1 to 30 μm, more preferably 1 to 15 μm, particularly 2 to 10 μm. Particles having an average particle size of less than 0.5 μm are difficult to manufacture and may be difficult to mix in large quantities, and if it exceeds 50 μm, the mechanical strength of the rubber cured product may be impaired. In addition, unevenness may remain on the surface of a roll, a belt or the like, which may cause a problem in performance.
The average particle size can be used a particle size distribution measuring apparatus by laser diffraction method or the like is determined as a cumulative weight average value D ₅₀ (or median diameter).

  Furthermore, a plurality of heat conductive powders having a single particle size (representing a narrow particle size distribution) may be used.

  In addition, the thermally conductive powder of component (D) is a silane coupling agent or a partially hydrolyzed product thereof, an alkylalkoxysilane or the like 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 partially hydrolyzed product, 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).

  (D) Although the compounding quantity of the heat conductive powder of a component is based also on the density of the heat conductive powder to mix | blend, it is 80-2,000 mass parts with respect to 100 mass parts of (A) component, Preferably it is 100-1. 500 parts by mass. If it is less than 80 parts by mass, the necessary thermal conductivity cannot be obtained, and if it exceeds 2,000 parts by mass, physical properties such as rubber strength will be significantly reduced.

In addition, since a high thermal conductive roll or belt is necessary for use, the thermal conductivity of the silicone rubber composition of the present invention is preferably 0.5 W / m · k or more, more preferably 1.0 W / m. It is desirable from the viewpoint of speeding up the recent copying machine that it is m · k or more. As a measure of the amount of powder blending the thermal conductivity of component (D) with the organopolysiloxane of component (A) and having a thermal conductivity of 0.5 W / m · k, The amount of alumina is preferably 180 parts by mass or more for alumina, 80 parts by mass or more for metal silicon, and 130 parts by mass or more for silicon carbide.
The thermal conductivity is measured by a disk heat flow meter method (ASTM E1530 compliant) using UNITHERM 2021 manufactured by Anter or a hot wire type thermal conductivity meter such as rapid thermal conductivity meter QTM-D3 manufactured by Kyoto Electronics Industry Co., Ltd. Although it can be measured, the hot wire type thermal conductivity meter is widely used since the measurement time is short, and the measured value by the hot wire type thermal conductivity meter is also adopted in the present invention.

  Furthermore, the platinum or platinum-based compound as the component (E) is used as a catalyst for promoting the addition curing reaction (hydrosilation) between the component (A) and the component (B) or (C). . As platinum or platinum-based compounds, known compounds can be used. Specifically, platinum element alone, platinum black, chloroplatinic acid, chloroplatinic acid-modified products, chloroplatinic acid and olefin, aldehyde, vinylsiloxane, acetylene Examples include complexes with alcohols and the like.

  In addition, although the addition amount of platinum or a platinum-type compound is a catalyst amount and can be suitably increased / decreased according to the desired cure rate, Usually, platinum metal mass is 1 to 2,000 ppm, and especially the range of 1 to 200 ppm. It is preferable to do.

In addition, when it is necessary to impart strength to the composition of the present invention, it is effective to add finely powdered silica having a specific surface area of 50 m ² / g or more by the BET method. Specific examples of the fine powdery silica include Aerosil 130, 200, and 300 (manufactured by Nippon Aerosil Co., Ltd., Degussa), Cabosil MS-5, and MS-7 (Cabot Corporation) as hydrophilic silica. Aerosil R-812, R-812S, R-972, R-974 (Nippon Aerosil Co., Ltd.) as hydrophobic silica Manufactured by Degussa), Rheorosil MT-10 (manufactured by Tokuyama Soda Co., Ltd.), Nipsil SS series (manufactured by Nippon Silica Co., Ltd.) and the like.

  In order to improve the properties of the cured product, the addition amount of these finely divided silicas should be 0.2 to 100 parts by weight, particularly 0.5 to 50 parts by weight, per 100 parts by weight of component (A) diorganopolysiloxane. Is preferred.

  In the composition of the present invention, when it is necessary to adjust the curing time for practical use, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclo is used as a control agent. Usually low molecular weight cyclic organopolysiloxane containing about 4 to 8 silicon atoms such as tetrasiloxane, triallyl isocyanurate, alkyl maleate, acetylene alcohols or their silanes, siloxane modified products, hydroperoxide, tetramethyl Ethylenediamine, benzotriazole, or a mixture thereof may be added. In addition, the addition amount of these control agents can be made into a normal amount in the range which does not prevent the effect of this invention.

  In the present invention, it is optional to add a conductive material to form a conductive silicone rubber composition. The type and amount of the conductive material are not limited, but conductive metal oxide powder such as conductive carbon black, conductive zinc white, and conductive titanium oxide, and metal powder such as copper powder, silver powder, and gold powder can be used. 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. Specific examples of acetylene black include Denka Black (manufactured by Denki Kagaku Kogyo Co., Ltd.) and Shaunigan acetylene black (manufactured by Shaunigan Chemical Co., Ltd.). ), Vulcan C (manufactured by Cabot), etc., as super conductive furnace black, Connex SCF (manufactured by Continental Carbon), Vulcan SC (manufactured by Cabot), etc., as extra conductive furnace black, Asahi HS-500 (Made by Asahi Carbon Co., Ltd.), Vulcan XC-72 (made by Cabot Corp.), etc., examples of the conductive channel black include Kourax L (made by Degussa), etc. It is also possible to use a click EC and 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 amount of the conductive material added may be a resistance value at which the cured product of the conductive silicone rubber composition becomes conductive, that is, an amount such that 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 of components, 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 50 parts by mass, physical mixing may be difficult or the mechanical strength may be reduced. The rubber elasticity may not be obtained.

  Furthermore, in the present invention, as other components, quartz powder, diatomaceous earth, semi-reinforcing fillers such as calcium carbonate, inorganic pigments such as cobalt blue, colorants such as organic dyes, cerium oxide, zinc carbonate, manganese carbonate, Addition of heat resistance and flame retardancy improvers such as bengara, titanium oxide and carbon black is also possible, and these addition amounts can be normal amounts within a range not impeding the effects of the present invention.

  Although it does not specifically limit as a preparation method of the highly heat conductive silicone rubber composition of this invention, The mixing method of heat conductive powder (D) uses apparatus, such as a planetary mixer and a kneader, at normal temperature (A), ( It may be mixed with the component B) or at a high temperature of 100 to 200 ° C.

  When heat treatment is performed, for example, components (A) and (D) 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 usually required by various molding methods for molding a silicone rubber composition, such as LIM injection molding and mold pressure molding. The molding conditions are not particularly limited, but a range of several seconds to one hour at 80 to 400 ° C. is preferable. When secondary vulcanization is performed after molding, secondary vulcanization is preferably performed at 150 to 250 ° C. for 1 to 30 hours.

The fixing roll and fixing belt of the present invention have a highly heat-conductive cured product layer of the above silicone rubber composition on the outer peripheral surface of the core metal or on either the front or back surface of a substrate (belt base material) made of a heat resistant resin or metal. In this case, the material and dimensions of the core metal and the belt base material can be appropriately selected according to the type of the product. For example, as the core metal, iron, stainless steel (SUS), aluminum In addition to the same metal as the core metal, a polyamide resin, a polyimide resin, and the like can be used as the belt base material. 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. In this case, the desired roll thickness (thickness of the silicone rubber elastic layer) is about 0.2 to 50 mm, and the desired belt thickness (thickness of the silicone rubber elastic layer) is about 50 μm to 5 mm.

  In the fixing roll and the fixing belt of the present invention, a fluororesin or a 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. Among these, PFA and PTFE latex are particularly preferable. The thickness of the fluororesin or fluororubber layer is usually preferably 1 to 300 μm, more preferably about 3 to 150 μm, in both the fixing roll and the fixing belt.

  Hereinafter, examples and comparative examples will be shown (each main formulation is shown in Table 1), and the present invention will be specifically described. However, the present invention is not limited to the following examples. In addition, all the parts in each example are mass parts.

[Examples 1 and 2]
60 parts of dimethylpolysiloxane (polymerization degree 500) capped with dimethylvinylsiloxy groups at both ends, hydrophobized fumed silica with a specific surface area of 110 m ² / g by BET method (R made by Nippon Aerosil Co., Ltd.) -972) 1 part, 2 parts of iron oxide (Fe ₂ O ₃ ) having an average particle diameter of 0.10 μm and 280 parts of spherical alumina powder having an average particle diameter of 10 μm are placed in a planetary mixer and kept at room temperature (23 ° C.) for 2 hours. Stirring was performed. 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, amounts shown in Table 1 for hydrogenmethylpolysiloxanes represented by the following compound A, amounts shown in Table 1 for hydrogenpolysiloxanes having an aromatic ring represented by the following compound B Furthermore, 0.5 part of 3-glycidoxypropyltrimethoxysilane (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, 3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) Product name: KBM903) 0.2 part and 0.05 part of ethynylcyclohexanol as reaction control agent, platinum 50ppm was added vinylsiloxane complexes of platinum atoms, to prepare a highly thermally conductive silicone rubber composition and the stirring was continued for 15 minutes.
This silicone rubber composition was press-cured at 120 ° C. for 10 minutes, and further oven-cured at 200 ° C. for 4 hours. Then, according to JIS K6249, hardness, tensile strength, elongation at break, and 180 ° C./22 hours later Compression set was measured. Moreover, about the sheet | seat of thickness 12mm, thermal conductivity was measured with the rapid thermal conductivity meter (QTM-D3, Kyoto Electronics Industry Co., Ltd. make, hot wire system).

[Comparative Example 1]
For comparison, a liquid addition-curable silicone rubber composition not added with the compound B having the above structure added in Example 1 was similarly evaluated.

[Comparative Example 2]
For comparison, a liquid addition-curable silicone rubber composition in which a large amount of the compound B having the above structure added in Example 2 was added as shown in Table 1 was similarly evaluated.

[Examples 3 and 4]
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 metal silicon powder having an average particle diameter of 5 μm are placed in a planetary mixer and kept at room temperature (23 ° C.) for 2 hours. Stirring was performed. 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, 3.0 parts of hydrogenmethylpolysiloxane represented by the above compound A, and hydrogenpolysiloxane having an aromatic ring represented by the following compound C were added in the amounts shown in Table 1. Except for the above, a liquid addition-curable silicone rubber composition was prepared in the same manner as in Example 1 and evaluated in the same manner.

[Comparative Example 3]
For comparison, a liquid addition-curable silicone rubber composition to which the compound C having the above structure added in Example 4 was not added was similarly evaluated.

[Comparative Example 4]
For comparison, a liquid addition-curable silicone rubber composition in which a large amount of the compound C having the structure added in Example 4 was added as shown in Table 1 was evaluated in the same manner.

[Example 5]
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 metal silicon powder having an average particle diameter of 5 μm are placed in a planetary mixer and kept at room temperature (23 ° C.) for 2 hours. Stirring was performed. 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) A liquid addition-curable silicone rubber composition was prepared in the same manner as in Example 1, except that 40 parts of hydrogenpolysiloxane having an aromatic ring represented by Compound C was changed to 4.0 parts. And evaluated in the same manner.

[Examples 6 and 7]
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 ) with an average particle diameter of 0.10 μm, and 220 parts of pulverized silicon carbide powder with an average particle diameter of 5 μm pretreated with methyltrimethoxysilane are placed in a planetary mixer. The mixture was stirred at room temperature (23 ° C.) for 2 hours. 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, amount of hydrogen methylpolysiloxane represented by the above compound A shown in Table 1, amount of hydrogen polysiloxane having an aromatic ring represented by the following compound D added in Table 1 Further, a liquid addition-curable silicone rubber composition was prepared in the same manner as in Example 1 except that 0.5 part of 3-glycidoxypropyltrimethoxysilane (KBM403, supra) was added as a silane coupling agent. , Evaluated in the same way. The methyltrimethoxysilane-treated silicon carbide powder was produced by the following method.
1. To 100 parts of silicon carbide powder, 2.0 parts of methyltrimethoxysilane was sprayed at room temperature (23 ° C.).
2. The powder was stirred for 20 minutes in a stirrer, and then heated at 200 ° C./1 hour in a stationary state, and then cooled to room temperature to obtain the desired powder.

[Comparative Example 5]
For comparison, a liquid addition-curable silicone rubber composition to which the compound D having the above structure added in Example 6 was not added was similarly evaluated.

[Comparative Example 6]
For comparison, a liquid addition-curable silicone rubber composition in which a large amount of the compound D having the above structure added in Example 7 was added as shown in Table 1 was similarly evaluated.

[Comparative Example 7]
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 60 parts of pulverized metal silicon powder having an average particle diameter of 5 μm are placed in a planetary mixer and kept at room temperature (23 ° C.) for 2 hours. Stirring was performed. 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, 3.0 parts of hydrogen methylpolysiloxane represented by the above compound A is added, 0.05 parts of ethynylcyclohexanol as a reaction control agent, and platinum vinylsiloxane complex as platinum atom As a result, 50 ppm was added and stirring was continued for 15 minutes to prepare a high thermal conductive silicone rubber composition. This silicone rubber composition was cured in the same manner as in Example 1, and the physical properties and thermal conductivity were similarly investigated.

Evaluation of roll durability (Examples 1-7, Comparative Examples 1-7)
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, dried, and baked (150 ° C. × 15 minutes). The aluminum shaft was fixed in a mold, and the silicone rubber compositions of Examples and Comparative Examples were filled in the mold at a pressure of 10 kgf / cm ² , heated and cured at 150 ° C. for 30 minutes, and further heated at 200 ° C. for 4 minutes. Time post-curing was performed to obtain a silicone rubber roll having a wall thickness of 2 mm and a diameter of 16 mm. This roll is compressed in an aluminum drum with a diameter of 16 mm in an atmosphere of 200 ° C. so that the rubber wall thickness is 1 mm (50% compression), and the roll is rotated in the same direction at a speed of 1 revolution / second until the roll breaks. Investigate the time.

Evaluation of belt durability (Examples 3 to 5, Comparative Examples 3, 4, and 7)
[Example 3]
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 φ25 mm, width 235 mm). 101 A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied, dried, and baked (150 ° C. × 15 minutes). This was coated with the silicone rubber composition of Example 3 (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 Industries) 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 a fluororesin-coated silicone rubber having a fluororesin layer thickness of 5 μm was prepared by heating and baking at 300 ° C. for 1 hour. The belt was stretched between an aluminum heater roll (diameter φ19.6 mm) of a MICROLINE620CL manufactured by Monochrome Page Printer Oki Data, a φ6 mm metal rod, and an aluminum heater roll, thereby forming a companion belt fixing mechanism. The copying machine continuously copied 60,000 A4 size copying papers, but there were no paper wrinkles or paper jams, and all the copied images were clear.

[Examples 4 and 5]
A fixing belt was prepared in the same manner as in Example 3 except that the silicone rubber composition of Example 4 or 5 was used instead of the silicone rubber composition (Example 3). When the copy paper was continuously passed, 60,000 copies were continuously copied, but all the copied images were clear with no paper wrinkles or paper jams.

[Comparative Example 3]
A fixing belt was prepared in the same manner as in Example 3 except that the silicone rubber composition of Comparative Example 3 was used instead of the silicone rubber composition (Example 3). As a result, the image became unclear from the 1,000th sheet, paper wrinkles were generated from the 1,200th sheet, and the experiment was stopped. When the fixing belt was confirmed, "belt blistering" due to rubber layer destruction occurred.

[Comparative Example 4]
A fixing belt was prepared in the same manner as in Example 3 except that the silicone rubber composition of Comparative Example 4 was used instead of the silicone rubber composition (Example 3). When the paper was continuously fed, the image became unclear from the 2,200th sheet, paper wrinkles were generated from the 2,500th sheet, and the experiment was stopped. When the fixing belt was confirmed, "belt blistering" due to rubber layer destruction occurred.

[Comparative Example 7]
A fixing belt was prepared in the same manner as in Example 3 except that the silicone rubber composition of Comparative Example 7 was used instead of the silicone rubber composition (Example 3). When the paper was continuously fed, “smeared printing” occurred from the beginning of printing. When the printing surface was examined, it was found that the toner was peeled off due to insufficient toner melting temperature due to insufficient rubber thermal conductivity, and the experiment was stopped because the toner was peeled off.

  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 (6)

(A) The following average composition formula (1)
R ¹ _a SiO _{(4-a) / 2} (1)
(In the formula, R ¹ is the same or different unsubstituted or halogen-substituted monovalent hydrocarbon group, and a is a positive number of 1.8 ≦ a ≦ 2.205.)
Diorganopolysiloxane having a viscosity of 100 to 10,000,000 mPa · s at 25 ° C. having at least two aliphatic unsaturated groups in one molecule:
(B) The following average composition formula (2)
R ² _b H _c SiO _{(4-bc) / 2} (2)
Wherein R ² is the same or different unsubstituted or halogen-substituted monovalent aliphatic saturated hydrocarbon group, and b and c are 0.8 ≦ b ≦ 2.2 and 0.002 ≦ c ≦, respectively. 1.0 and a positive number satisfying 0.802 ≦ b + c ≦ 3.0.)
An organohydrogenpolysiloxane having a hydrogen atom bonded to at least three silicon atoms in one molecule: 0 to 20 parts by mass,
(C) Compound selected from the following (a) and (b): 0.01 to 5 parts by mass,
(A) The following average composition formula (3)
Q _d R ³ _e H _f SiZ _{(4-def) / 2} (3)
Wherein Q is a monovalent organic group having one or more aromatic rings, R ³ is an unsubstituted or halogen-substituted monovalent hydrocarbon group, and Z is selected from an oxygen atom or a divalent hydrocarbon group. And at least one is an oxygen atom, d, e, and f are 0 <d ≦ 2, 0 ≦ e ≦ 2, 0 <f ≦ 1, 0.8 ≦ d + e + f ≦ 3.0, respectively. (It is a positive number.)
The content of a monovalent organic group having a hydrogen atom bonded to at least two silicon atoms in one molecule and having an aromatic ring among the monovalent organic groups bonded to the silicon atom is 12 mol%. An organohydrogenpolysiloxane having a monovalent group selected from at least one group represented by the following formula in one molecule

(B) Organic having a hydrogen atom bonded to at least one silicon atom in one molecule and a monovalent or divalent aromatic ring-containing organic group represented by the following general formula (4) or (5) Compound

[Wherein, R ^{4 to} R ¹² are each a hydrogen atom, a halogen atom, an unsubstituted or halogen-substituted monovalent hydrocarbon group, or an alkoxy group, and X is a group selected from the following groups.

(R ¹³ and R ¹⁴ are each an unsubstituted or halogen-substituted monovalent hydrocarbon group.)]
(D) Thermally conductive powder having an average particle size of 0.5 to 50 μm: 80 to 2,000 parts by mass, and (E) platinum or a platinum-based compound: a catalytic amount, and an office machine characterized by comprising High heat conductive silicone rubber composition for fixing roll for office use or fixing belt for office machine .   The heat conductive powder is at least one selected from alumina, metal silicon and silicon carbide, and the addition curable silicone rubber composition gives a cured product having a thermal conductivity of 0.5 W / m · k or more. The silicone rubber composition according to claim 1.   A fixing roll having a silicone rubber layer formed on the outer peripheral surface of a core metal, wherein the silicone rubber layer is a cured product of the silicone rubber composition according to claim 1 or 2.   In the fixing roll in which a fluororesin layer is formed on the outer peripheral surface of the metal core via a silicone rubber layer, the silicone rubber layer is a cured product of the silicone rubber composition according to claim 1 or 2. Fluorine resin-coated fixing roll. In the fixing belt in which a silicone rubber layer is formed on either the front or back surface of a substrate made of a heat resistant resin or metal, the silicone rubber layer is a cured product of the silicone rubber composition according to claim 1 or 2. Features a fixing belt. The silicone rubber composition according to claim 1 or 2, wherein the silicone rubber layer is a fixing belt in which a fluorine-based resin layer is formed on either the front or back surface of a substrate made of a heat resistant resin or metal via a silicone rubber layer. A fluororesin-coated fixing belt, which is a cured product of