WO2021251078A1 - Addition-curing liquid electroconductive silicone rubber composition and electrophotographic image formation member - Google Patents

Abstract

The present invention provides an addition-curing liquid electroconductive silicone rubber composition characterized by comprising (A) a liquid organopolysiloxane containing at least two silicon-atom-bonded alkenyl groups in one molecule: 100 parts by mass, (B) an organohydrogenpolysiloxane containing at least two silicon-atom-bonded hydrogen atoms in one molecule, (C) a platinum group metal-based catalyst as an addition reaction catalyst, (D) a carbon material: 1-50 parts by mass, and (E) a lithium-containing antistatic agent: 0.005-0.2 parts by mass with respect to a total mass of the components (A) and (B). Thus, provided are an addition-curing liquid electroconductive silicone rubber composition for an electrophotographic image formation member, the composition providing a cured product having satisfactory charge decay, and an electrophotographic image formation member which includes, as an elastic layer, a cured product obtained from the composition.

Description

Additive-curing liquid conductive silicone rubber composition and electrophotographic image forming member

INDUSTRIAL APPLICABILITY The present invention relates to an electrophotographic image forming member used in an addition-curable liquid conductive silicone rubber composition and an image forming apparatus using an electrophotographic method, particularly a developing roll or a developing belt (roll for office machine or office machine). Belt for).

Conventionally, various conductive rubbers in which a conductive material is blended with a rubber-like substance exhibiting electrical insulation are known. For example, conductive rubber in which carbon black or the like is blended as a conductive material is applied in a wide range of fields. .. On the other hand, silicone rubber, which is one of the electrically insulating rubber-like materials, has excellent heat resistance, cold resistance, and weather resistance, and is widely used as an electrically insulating rubber, but is conductive like other rubber-like materials. By adding a material, it has also been put into practical use as a conductive rubber.

In this case, the conductive material to be added to the conductive silicone rubber is, for example, various metal powders such as carbon black, graphite, silver, nickel, and copper, various non-conductive powders, and a metal such as silver on the surface of short fibers. Frequently, a mixture of treated material, carbon fiber, metal fiber, etc. can reduce the volume resistance of silicone rubber depending on the type and filling amount of the conductive material without impairing the unique characteristics of rubber. Is used for.
In particular, the addition-curing type liquid silicone rubber is widely used as a developing roll material because it has low viscosity and excellent moldability even when a conductive material such as carbon black is blended, and it can be cured in a short time. in use.

Image forming apparatus is required to have finer print characteristics with the recent refinement and speeding up of image formation. The developing member is required to have excellent chargeability from the viewpoint of toner transportability, and is also required to have charge attenuation. After the toner is supplied to the image carrier of the developing member, if the charge attenuation does not proceed rapidly, the cleaning property of the toner by the toner supply roll or the like deteriorates.
Although it is possible to reduce the chargeability by increasing the amount of the conductivity-imparting agent such as carbon black, there is a possibility that the viscosity will be greatly increased by increasing the amount of carbon black. Further, even if the resistance value is significantly lower than the target resistance value, the desired charge attenuation may not be obtained.

Patent Documents 1 to 3 exemplify a conductive material in which a conductive material having an ionic conductive mechanism and a conductive material having an electronic conductive mechanism are used in combination. However, the dependence of the resistance value on the voltage and the environment with respect to temperature and humidity are exemplified. Only the stabilization of the resistance value and the uniformity of the resistance value in the above are described, and the charge attenuation characteristic is not described.

Patent Document 4 exemplifies a material to which an organic boron compound having a hydroxy group and a BN type molecular compound, which is a reaction product of a tertiary amine compound, are added as an antistatic agent to silicone rubber. However, no mention is made of lithium salts.

Patent Document 5 exemplifies a developing roll having excellent charge attenuation by using carbon and an ionic liquid in combination, but does not describe the antistatic property of the ionic conductive material.

Patent Document 6 exemplifies a material to which an antistatic agent selected from lithium salts is added. However, only the insulating material is mentioned, and the combined use with carbon is not mentioned.

Japanese Unexamined Patent Publication No. 2001-140854 Japanese Unexamined Patent Publication No. 2002-116638 Japanese Unexamined Patent Publication No. 2003-82232 Japanese Unexamined Patent Publication No. 2018-049153 Patent No. 5396540 Japanese Unexamined Patent Publication No. 2006-265340

The present invention has been made in view of the above circumstances, and is an addition-curable liquid conductive silicone rubber composition that gives a cured product having good charge attenuation, and an electrophotographic image-forming member having the cured product of the composition as an elastic layer. The purpose is to provide.

In order to solve the above problems, in the present invention,
(A) Liquid organopolysiloxane containing at least two alkenyl groups bonded to a silicon atom in one molecule: 100 parts by mass,
(B) Organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms in one molecule: The number of hydrogen atoms bonded to silicon atoms contained in the component (B) is the component (A). Amount of 0.5 to 10 per alkenyl group bonded to a silicon atom contained in
(C) Platinum group metal-based catalyst as an addition reaction catalyst: An amount of 0.5 to 1,000 ppm in terms of platinum group metal with respect to the total mass of the components (A) to (B).
(D) Carbon material: 1 to 50 parts by mass,
(E) Antistatic agent containing lithium: an amount of 0.005 to 0.2 parts by mass with respect to the total mass of the components (A) to (B).
Provided is an addition-curable liquid conductive silicone rubber composition containing the above.

With such a thing, it is possible to obtain a cured product having good charge attenuation after curing.

Further, the _{component (E), LiBF 4, LiClO 4, LiPF} 6, LiAsF 6, LiSbF 6, LiSO 3 CF 3, LiN (SO 2 CF 3) 2, LiSO 3 C 4 F 9, LiC (SO 2 CF ₃ ) It is preferable that the amount is one or more selected from ₃ and LiB (C ₆ H ₅ ) _4.

If the antistatic agent is such, the antistatic property is particularly good.

Among them, the component (E) is preferably _{LiN (SO 2} CF ₃ ) _2.

This antistatic agent has particularly good antistatic attenuation.

Further, the present invention provides an electrophotographic image-forming member having an elastic layer made of a cured product of the obtained addition-curable liquid conductive silicone rubber composition.

Such an electrophotographic image forming member shows good charge attenuation.

Further, it is preferable that the electrophotographic image forming member is a member selected from a developing roll and a developing belt.

These above-mentioned members are preferably used as members having good charge attenuation.

According to the present invention, an addition-curable liquid conductive silicone rubber composition for an electrophotographic image-forming member that gives a cured product having good charge damping property and an electrophotographic type having the cured product of the composition as an elastic layer. An image forming member is obtained.

As described above, there has been a demand for the development of a conductive composition that gives a cured product having good charge attenuation, and an electrophotographic image forming member having the cured product of the composition as an elastic layer.

As a result of diligent studies to achieve the above object, the present inventors have found that, in the addition-curing liquid conductive silicone rubber composition containing the components (A) to (E) described later, particularly the carbon of the component (D). In addition, by adding a specific amount of an antistatic agent containing lithium as a component (E), the cured product obtained by heating and curing this realizes good heat resistance and antistatic attenuation, and develop rolls, development belts, etc. It has been found that it is suitable for the electrophotographic image forming member of the above, and the present invention has been made.

Therefore, the present invention provides the following addition-curable liquid conductive silicone rubber composition and electrophotographic image-forming member.

That is, the present invention
(A) Liquid organopolysiloxane containing at least two alkenyl groups bonded to a silicon atom in one molecule: 100 parts by mass,
(B) Organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms in one molecule: The number of hydrogen atoms bonded to silicon atoms contained in the component (B) is the component (A). Amount of 0.5 to 10 per alkenyl group bonded to a silicon atom contained in
(C) Platinum group metal-based catalyst as an addition reaction catalyst: An amount of 0.5 to 1,000 ppm in terms of platinum group metal with respect to the total mass of the components (A) to (B).
(D) Carbon material: 1 to 50 parts by mass,
(E) Antistatic agent containing lithium: an amount of 0.005 to 0.2 parts by mass with respect to the total mass of the components (A) to (B).
It is an addition hardening type liquid conductive silicone rubber composition containing.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

<Additional curing type liquid conductive silicone rubber composition>
The addition-curable liquid conductive silicone rubber composition of the present invention contains at least the following components (A) to (E).

[(A) component]
The component (A) is an organopolysiloxane liquid at 25 ° C. containing two or more alkenyl groups bonded to silicon atoms in one molecule, and is a base polymer (main agent) of the composition according to the present invention.

Examples of the molecular structure of the component (A) include linear, cyclic, branched chain, and three-dimensional network (resin), but the main chain basically consists of repeating diorganosiloxane units. A linear diorganopolysiloxane having both ends of the molecular chain sealed with a triorganosyloxy group is preferable. When the molecular structure of the organopolysiloxane component (A) is linear or branched, the position of the silicon atom to which the alkenyl group is bonded in the molecule of the organopolysiloxane is the terminal of the molecular chain (that is, that is, Either one or both of the triorganosyloxy group) and the middle of the molecular chain (that is, the bifunctional diorganosiloxane unit or the trifunctional monoorganosylsesquioxane unit located at the non-terminal of the molecular chain) may be used. As the component (A), a linear diorganopolysiloxane containing at least an alkenyl group bonded to silicon atoms at both ends of the molecular chain is particularly preferable.

Examples of the alkenyl group bonded to the silicon atom in the component (A) include those having 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a cyclohexenyl group, a heptenyl group and the like, and a vinyl group is particularly preferable.

The content of the alkenyl group bonded to the silicon atom in the component (A) is 0.001 to the total of the monovalent organic group bonded to the silicon atom (that is, the unsubstituted or substituted monovalent hydrocarbon group). It is preferably 10 mol / 100 g, and particularly preferably 0.01 to 5 mol / 100 g.

Examples of the monovalent organic group bonded to the silicon atom other than the alkenyl group of the component (A) include monovalent hydrocarbon groups having the same or different carbon atoms of 1 to 12, preferably 1 to 10 carbon atoms. Be done. Specific examples of the monovalent organic group include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group and a heptyl group; a phenyl group, a trill group, a xsilyl group and a naphthyl group. Aryl groups such as benzyl group, aralkyl groups such as phenethyl group, etc., in which a part or all of the hydrogen atoms of these groups are replaced with halogen atoms such as fluorine, bromine, chlorine, etc., for example, chloromethyl group. , A halogen-substituted alkyl group such as a 3-chloropropyl group or a 3,3,3-trifluoropropyl group may be used. Among these, a methyl group is particularly preferable. The component (A) preferably does not contain an epoxy group.

The viscosity of the component (A) at 25 ° C. is preferably 50 to 500,000 mPa · s, more preferably 600 to 200,000 mPa · s. When the viscosity is within this range, the handling workability of the obtained conductive silicone rubber composition is good, and the mechanical properties of the cured product of the obtained conductive silicone rubber composition are good. In the present specification, the viscosity means a value measured by a rotational viscometer by the method described in JIS K 7117-1: 1999 at 25 ° C.

Specific examples of the organopolysiloxane of the component (A) include a trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer at both ends of the molecular chain, a trimethylsiloxy group-blocked methylvinylpolysiloxane at both ends of the molecular chain, and trimethyl at both ends of the molecular chain. Syroxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain double-ended dimethylvinyl syroxy group-blocked dimethylpolysiloxane, molecular chain double-ended dimethylvinylsiloxy group-blocked methylvinylpolysiloxane, molecular chain double-ended dimethylvinyl Syloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain double-ended dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain double-ended divinylmethylsiloxy group-blocked dimethylpolysiloxane, molecule Divinylmethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer at both ends of the chain, trivinylsiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain, trivinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer at both ends of the molecular chain, And a mixture of two or more of these organopolysiloxanes.

The organopolysiloxane of the component (A) may be used alone or in combination of two or more. Above all, it is preferable to use two or more kinds in combination because it becomes easy to adjust the composition of the present invention to a preferable viscosity range.

[(B) component]
The organohydrogenpolysiloxane of the component (B) reacts with the alkenyl group in the component (A) by hydrosilylation addition reaction and acts as a cross-linking agent (hardener). Various manufactured products such as linear, cyclic, branched chain, and three-dimensional network (resin-like) structures can be used, but hydrogen atoms bonded to at least two silicon atoms in one molecule can be used. It must have (hydrosilyl group represented by SiH) and does not substantially contain a hydroxyl group (that is, a silanol group) bonded to a silicon atom in the molecule.

The organohydrogenpolysiloxane of the component (B) may be used alone or in combination of two or more.

As this organohydrogenpolysiloxane, those represented by the following average composition formula (1) can be used.
R ⁴ _a H _b SiO _{(4-ab) / 2} (1)
(Wherein, R ⁴ is identical or different from each other, excluding the aliphatic unsaturated bonds such as alkenyl groups, preferably monovalent hydrocarbon groups bonded 1 to 10 carbon atoms, a silicon atom. Also, a Is 0.7 to 2.1, b is 0.001 to 1.0, and a + b is a positive number satisfying 0.8 to 3.0.)

In the above formula (1), R ⁴ is identical or different from each other, excluding the aliphatic unsaturated bonds such as alkenyl group, preferably a monovalent hydrocarbon group bonded 1 to 10 carbon atoms, a silicon atom, the monovalent hydrocarbon groups in this R ^4, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, butyl group, isobutyl group, tert- butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, octyl Alkyl groups such as groups, nonyl groups and decyl groups; aryl groups such as phenyl group, trill group, xylyl group and naphthyl group; aralkyl groups such as benzyl group, phenylethyl group and phenylpropyl group can be mentioned. A chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group and the like may be used in which a part or all of the hydrogen atom of the above is substituted with a halogen atom such as fluorine, bromine or chlorine. Monovalent hydrocarbon radicals of R ^4, is preferably an alkyl group, an aryl group, more preferably a methyl group. Further, a is 0.7 to 2.1, b is 0.001 to 1.0, and a + b is a positive number satisfying 0.8 to 3.0, preferably a is 1.0 to 1.0. 2.0 and b are positive numbers satisfying 0.01 to 1.0, and a + b are positive numbers satisfying 1.5 to 2.5.

The SiH group contained at least two in one molecule may be located at the end of the molecular chain or in the middle of the molecular chain, or may be located at both of them. The molecular structure of this organohydrogenpolysiloxane may be linear, cyclic, branched chain, or three-dimensional network structure, but the number of silicon atoms (or degree of polymerization) in one molecule is , Usually 2 to 300, preferably 3 to 150, more preferably 4 to 100, and the viscosity at 25 ° C. is usually 0.1 to 1,000 mPa · s, preferably 0.5 to 0.5. A liquid at 25 ° C. of about 500 mPa · s is used. The degree of polymerization can be determined, for example, as a polystyrene-equivalent number average degree of polymerization (number average molecular weight) or weight average degree of polymerization (weight average molecular weight) in GPC (gel permeation chromatography) analysis using toluene as a developing solvent. ..

Examples of the organohydrogenpolysiloxane of the component (B) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, and tris (hydrogendimethylsiloxy). Methylsilane, Tris (hydrogendimethylsiloxy) phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, trimethylsiloxy group-sealed methylhydrogenpolysiloxane at both ends of the molecular chain, trimethyl at both ends of the molecular chain Syloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain double-ended trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer, molecular chain double-ended trimethylsiloxy group-blocked dimethylsiloxane / methylhydro Gensiloxane / diphenylsiloxane copolymer, molecular chain double-ended dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane, molecular chain double-ended dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, molecular chain double-ended dimethylhydrogensiloxy group-blocked dimethyl Siloxane / Methylhydrogensyloxy group-blocked dimethylhydroxyloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer, dimethylhydrogensiloxy group-blocked dimethylsiloxane / diphenylsiloxane copolymer at both ends of the molecular chain, molecule In the dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane at both ends of the chain, the dimethylhydrogensiloxy group-blocked diphenylpolysiloxane at both ends of the molecular chain, and in each of these exemplary compounds, part or all of the methyl group is an ethyl group, a propyl group, etc. those of substituted with other alkyl groups, ^wherein: the siloxane units represented by the formula _R 5 _{3 SiO ^1/2:} siloxane units represented by the formula _R 5 2 _{HSiO 1/2:} represented by _{SiO 4/2} organosiloxane copolymers consisting of siloxane units of the ^formula: siloxane units represented by the formula _R 5 2 _{HSiO 1/2:} organosiloxane copolymers composed of siloxane units represented by _{SiO 4/2,} ^wherein: R 5 HSiO _{2 /} siloxane units represented by ₂ and ^formula siloxane units or of the formula represented by R _{5 SiO 3/2:} or siloxane units represented by _{HSiO 3/2} Examples thereof include an organosiloxane copolymer composed of these, and a mixture composed of two or more of these organopolysiloxanes. Incidentally, the R ⁵ is a group selected from aryl alkyl group, or a C 6-12 having 1 to 8 carbon atoms, particularly preferably a methyl group.

The blending amount of the component (B) is 0.5 to 10 (or mol) of silicon atom-bonded hydrogen atoms in the component (B) with respect to one silicon atom-bonded alkenyl group (or mol) in the component (A). ), The amount is preferably 0.6 to 5 (or mol), and more preferably 0.7 to 2.0 (or mol).

If the number of silicon atom-bonded hydrogen atoms in the component (B) is less than 0.5 with respect to one silicon atom-bonded alkenyl group in the component (A), the conductive silicone rubber composition is not sufficiently cured. The desired strength may not be obtained. If the number exceeds 10, the heat resistance of the cured product of the conductive silicone rubber composition may be extremely deteriorated.

[(C) component]
Examples of the addition reaction catalyst of the component (C) include platinum black, second platinum chloride, platinum chloride acid, a reaction product of platinum chloride acid and a monovalent alcohol, a complex of platinum chloride acid and olefins, platinum bisacetoacetate and the like. Examples thereof include platinum-based metal catalysts such as platinum-based catalysts, palladium-based catalysts, and rhodium-based catalysts.

The blending amount of the component (C) can be a catalytic amount, and usually, the total amount of the component (A) and the component (B) (total amount of polymer having a siloxane bond) is 0. It may be 5 to 1,000 ppm, particularly 1 to 500 ppm. If the amount added is too small, the curability is lowered, and if the amount added is too large, the cost becomes high and it becomes uneconomical.

[(D) component]
The carbon material of the component (D) is necessary for obtaining conductivity (or volume resistivity) in a specific region, and a known production method and type of carbon material can be used. Here, "conductivity in a specific region" specifically means that the volume resistivity of the cured product of the obtained conductive silicone rubber composition is usually 0.1 to 10,000,000 Ω · m, preferably 0.1 to 10,000,000 Ω · m. Is designed to be 1 to 10,000,000 Ω · m, more preferably 10 to 1,000,000 Ω · m. The conductivity of the carbon material differs depending on the production method, but in the present invention, any carbon material can be used as long as it obtains the desired conductivity when blended and kneaded.

The carbon material is not particularly limited, but is, for example, acetylene black, conductive furnace black (CF), super conductive furnace black (SCF), extra conductive furnace black (XCF), conductive channel black (CC), 1, Examples include carbon blacks such as furnace black and channel black heat-treated at a high temperature of about 500 to 3,000 ° C., carbon nanoparticles, carbon nanoparticles, carbon nanotubes, graphene, graphite, etc., and one of them. Can be used alone or in combination of two or more.

Specifically, acetylene black includes Denka Black (manufactured by Denka) and Shaunigan acetylene black (manufactured by Shaunigan Chemical), and conductive furnace black includes Continex CF (manufactured by Continental Carbon) and Balkan. C (manufactured by Cabot), etc., as Super Conductive Furness Black, Continex SCF (manufactured by Continental Carbon), Balkan SC (manufactured by Cabot), etc., as Extra Conductive Furness Black, Asahi HS-500 (Asahi Carbon) , Vulcan XC-72 (manufactured by Cabot), etc., and Courax L (manufactured by Degussa), etc. are exemplified as the conductive channel black, and Ketjen Black EC-350, which is a kind of furnace black, and Ketchen Black EC-600JD (manufactured by Ketchen Black International), ENSACO260G, ENSACO250G manufactured by the oil combustion method that does not include the quenching process with water in the oil combustion reaction stop process, and SUPER P Li (IMERYS) for battery grade. (Manufactured) can also be used.

The amount of impurities, especially sulfur and sulfur compounds, in the carbon black produced by the furnace method is preferably 6,000 ppm or less, more preferably 3,000 ppm or less in terms of the concentration of sulfur elements. In addition, acetylene black and oil furnace method carbon having a high degree of carbon crystallinity are particularly preferably used in the present invention because they have a low impurity content.

The blending amount of the carbon material (D) is 1 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A). ..

If the amount of the carbon material is too large, the mechanical properties of the cured product of the conductive silicone rubber composition may deteriorate, and the viscosity of the conductive silicone rubber composition becomes high, so that the moldability when producing a roll is increased. , Workability such as coating property may deteriorate. If the amount of the carbon material blended is too small, the conductivity of the target product may not be obtained.

In this method of adding / mixing the carbon material, it is possible to add / mix at the same time as the components (A) to (C), but it is preferable that the carbon material is liquid in a state of being dispersed in advance in a higher viscosity state. A method of adjusting the viscosity by adding oil (liquid organopolysiloxane of the component (A)) so as to be easy to mold is preferable.

Specifically, first, a part of the liquid organopolysiloxane of the component (A) is added and mixed with the total amount of the carbon material of the component (D), and the carbon material is sufficiently dispersed. At this time, a surface treatment agent may be added, or the mixture may be mixed while heating at about 100 to 180 ° C. After mixing, the remaining components (A) and (B) and (C) are added, and the mixture is sufficiently stirred again to obtain a liquid silicone rubber composition having a desired viscosity.

In order to further impart conductivity to the cured product (elastic layer) of the conductive silicone rubber composition, another conductive agent may be used in combination with the carbon material of (D), if necessary. As such other conductive agents, for example, various conductive metals or alloys such as aluminum, copper, tin and stainless steel, tin oxide, zinc oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution and the like are used. Examples thereof include metal oxides that have been conductively treated.

[(E) component]
As the antistatic agent containing lithium component (E), the lithium salt is preferably particularly excellent in charge decay property, _{specifically, LiBF 4, LiClO 4, LiPF} 6, LiAsF 6, LiSbF 6, LiSO 3 CF 3, Examples thereof include LiN (SO ₂ CF ₃ ) ₂ , LiSO ₃ C ₄ F ₉ , LiC (SO ₂ CF ₃ ) ₃ , and LiB (C ₆ H ₅ ) ₄ . These may be used alone or in combination of two or more. LiN (SO ₂ CF ₃ ) ₂ is more preferable.

Further, in the present invention, an ionic conductive agent other than these, an electronic conductive material such as carbon, and other organic polymer-based antistatic agents such as polyether can be used in combination.

The amount of the antistatic agent containing lithium as the component (E) is 0.005 to 0.2 parts by mass with respect to the total mass parts of the components (A) to (B), preferably 0.005. The amount is up to 0.1 part by mass, more preferably 0.005 to 0.05 part by mass. If it is less than 0.005 parts by mass, a sufficient antistatic effect may not be obtained. If it is more than 0.2 parts by mass, compression set and heat resistance may deteriorate.

[Reinforcing silica fine powder]
Addition of an inorganic filler other than the above-mentioned components (A) to (E) to the silicone rubber composition according to the present invention is optional, and reinforcing silica fine powder can be added.

In order to obtain a silicone rubber composition having excellent mechanical strength, the reinforcing silica fine powder preferably has a specific surface area (BET adsorption method) of 10 m ² / g or more, particularly 50 to 400 m ² / g. Examples of the reinforcing silica fine powder include aerosol silica (dry silica) and precipitated silica (wet silica), and aerosol silica (dry silica) is preferable.

Examples of these usable reinforcing silica fine powders as commercial products include Aerosil 130, 200, 300 (trade name manufactured by Nippon Aerosil Co., Ltd.), Cab-O-sil MS-5, MS-7, HS-5, HS. -7 (Product name manufactured by Cabot), SantocelFRC, CS (Product name manufactured by Monsanto), Nipsil VN-3 (Product name manufactured by Nippon Silica Industry Co., Ltd.) and the like can be mentioned. Further, these surfaces may be hydrophobized with organopolysiloxane, organopolysilazane, chlorosilane, alkoxysilane or the like. These silicas may be used alone or in combination of two or more.

Since the reinforcing silica fine powder aggravates the compression set and has a great influence on the change in volume resistivity with time, it is desirable that the amount added to the conductive silicone rubber composition is small.

In order to blend the reinforcing silica fine powder without affecting the volume resistivity and the compression set, 0 to 5 parts by mass with respect to 100 parts by mass of the organopolysiloxane (A) component in the conductive silicone rubber composition. In particular, the blending amount is preferably 0 to 3 parts by mass. The lower limit of the blending amount can be 0.1 parts by mass or more.

[Other inorganic fillers, etc.]
Examples of the inorganic filler other than the reinforcing silica fine powder include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, and hollow fillers.

These inorganic fillers include silane-based coupling agents or partial hydrolysates thereof, alkylalkoxysilanes or partial hydrolysates thereof, organic silazanes, titanate-based coupling agents, organopolysiloxane oils, and hydrolyzable functional group-containing organos. It may be surface-treated with polysiloxane or the like. These treatments may be carried out in advance by treating the inorganic filler itself, or may be carried out at the time of mixing with the oil.

The blending amount is preferably about 0 to 30 parts by mass with respect to 100 parts by mass of the organopolysiloxane (A) to (B) components in the silicone rubber composition.

Further, for the purpose of imparting thermal conductivity, a thermally conductive filler powder (for example, metallic silicon powder, alumina, aluminum, silicon carbide, silicon nitride, magnesium oxide, magnesium carbonate, zinc oxide, aluminum nitride, graphite, fibrous graphite). Etc.) is optional.

In addition, if necessary, hydrosilylation reaction control agents such as nitrogen-containing compounds, acetylene compounds, phosphorus compounds, nitrile compounds, carboxylates, tin compounds, mercury compounds, sulfur compounds, various additives, flame retardants, heat resistant agents, etc. It is also optional to mix.

[Preparation of Conductive Silicone Rubber Composition and Molding thereof]
The conductive silicone rubber composition of the present invention uses a normal mixing stirrer such as a kneader or a planetary mixer, a kneader or the like, and in addition to the above components (A) to (E), other components as necessary. It can be prepared by uniformly mixing (reinforcing silica fine powder and other inorganic fillers).

Molding methods for the conductive silicone rubber composition include casting molding, injection molding, coating, etc., and precure in the range of 10 seconds to 1 hour at a temperature of 100 to 300 ° C. is preferably used as the curing condition. Will be done. Further, for the purpose of reducing the low-molecular-weight siloxane component that causes a decrease in compression set, post-cure (secondary cure) for about 30 minutes to 70 hours in an oven at 120 to 250 ° C. after molding is performed. You may go.

The thickness of the elastic layer (silicone rubber sheet) made of the cured product of the conductive silicone rubber composition thus obtained is not particularly limited, but is usually 0.1 mm to 20 mm, preferably 1 mm to 2 mm.

According to the present invention, an electrophotographic image forming member having this elastic layer can be obtained.

The volume resistivity of the cured product may be any range of conductivity as long as it can be applied to a developing roll or a developing belt, but is usually 0.1 to 10,000,000 Ω · m, preferably 1 to 10,000,000 Ω · m. , More preferably 10 to 1,000,000 Ω · m. Here, the volume resistivity can be measured according to JIS K6249.

Regarding the antistatic level of the cured product, the time required for the withstand voltage to be halved after charging static electricity to the surface of the molded product by corona discharge using a static Honest meter (manufactured by Sisid Electrostatic Co., Ltd.) is 4 It is preferably less than a second.

The cured product of the conductive silicone rubber composition obtained by the present invention is particularly useful as an electrophotographic image forming member (particularly a developing roll, a developing belt, etc.).

For example, a single-layer roll in which the outer peripheral surface of the core metal is coated with a silicone rubber layer which is a cured product of the conductive silicone rubber composition, or the conductive silicone on the front and back surfaces of a base material made of a heat-resistant resin or a metal. It may be used as a single-layer belt coated with a silicone rubber layer which is a cured product of the rubber composition, or a roll obtained by further coating a resin such as a polyimide resin, a urethane resin, or a fluororesin on the silicone rubber layer. Or as a belt. In that case, the silicone rubber layer may be coated with only one layer on the surface (outer peripheral surface), or may be coated with two or more layers. Of these, those in which the outermost surface of the roll or belt is coated with urethane resin, fluorine-based resin, or the like is preferable from the viewpoint of durability such as abrasion resistance.

Here, the material of the core metal or the base material is preferably selected from iron, stainless steel, aluminum, polyamide / polyimide resin, and PEEK (polyetheretherketone).

Further, as the fluorine-based resin, a fluorine-based resin coating material, a fluorine-based resin tube, or the like can be used, and as the fluorine-based resin coating material, for example, a latex of polytetrafluoroethylene resin (PTFE) or a Daiel latex. (Fluorine-based latex manufactured by Daikin Industries, Ltd.) and the like can be mentioned, and commercially available products can be used as the fluorine-based resin tube, for example, polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether co-weight. Examples thereof include a coalesced resin (PFA), an ethylene fluoride-polypropylene copolymer resin (FEP), a polyvinylidene fluoride resin (PVDF), and a polyvinyl fluoride resin, and among these, PFA and PTFE latex are particularly preferable.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. The viscosity described below is a numerical value at 25 ° C. measured by the rotational viscometer described in JIS K 7117-1: 1999.

[Example 1]
Both ends of the molecular chain are sealed with vinyl dimethylsiloxy groups, the amount of alkenyl groups is 0.0071 mol / 100 g, the viscosity is 9,000 mPa · s, 45 parts by mass of dimethylpolysiloxane (A1), acetylene black (Denka Black, Denka Co., Ltd.). (D) 9 parts by mass was mixed with a planetary mixer for 30 minutes, and then passed through 3 rolls twice. After returning this to the planetary mixer, 100 parts by mass of dimethylpolysiloxane (A1), both ends of the molecular chain are sealed with trimethylsiloxy groups, and dimethylsiloxane / methylhydrogensiloxane having a silicon atom-bonded hydrogen atom in the side chain. Siloxane (B) (silicon atom-bonded hydrogen atom content = 0.0032 mol / g) 5.2 parts by mass, 1-ethynylcyclohexanol 0.1 parts by mass, platinum chloride acid / 1,3-divinyltetramethyldi 0.22 parts by mass of dimethylpolysiloxane solution (C) containing 1% by mass of siloxane complex as platinum atom content, 15 parts by mass of diatomaceous soil as an inorganic filler, and 20 _{parts by mass of LiN (SO 2} CF ₃ ) _{2 as an antistatic agent.} 0.10 parts of the% adipic acid ester solution (E) was mixed at room temperature with a planetary mixer for 30 minutes to prepare composition A. Next, the prepared composition A was made into a silicone rubber sheet by press curing at 120 ° C. for 10 minutes, then subjected to a secondary heat treatment at 200 ° C. for 4 hours, and the compression set and volume resistivity were measured according to JIS K 6249. did. The results are shown in Table 1.

Next, a silicone rubber sheet was prepared in the same manner as above, and a silicone-modified urethane coating material (X-93-1549: manufactured by Shin-Etsu Chemical Co., Ltd.) was applied as a coating layer to the surface of the molded product to form a coating layer of 10 to 30 μm. Using a static electricity meter (Sisid Electrostatic Co., Ltd.), the surface of the molded product was charged with static electricity by corona discharge, and then the time required for the voltage band to be halved was measured. Table 1 shows the evaluation results of the charge decay rate, assuming that the time until the charge is halved is 4 seconds or less, 〇, or longer than 4 seconds, or the withstand voltage does not become 0 even after 60 seconds have passed. Described.

[Example 2]
_{In Example 1, all the compositions were the same except that 0.1 part of LiN (SO 2} CF ₃ ) ₂ 20% by mass adipate solution (E) was replaced with 0.18 part by mass as an antistatic agent. Table 1 shows the results of preparing the product B and performing the same evaluation as in Example 1.

[Example 3]
_{In Example 1, all the compositions were the same except that 0.1 part of LiN (SO 2} CF ₃ ) ₂ 20% by mass adipate solution (E) was replaced with 0.26 part by mass as an antistatic agent. Table 1 shows the results of preparing the product C and performing the same evaluation as in Example 1.

[Example 4]
_{In Example 1, all the compositions were the same except that 0.1 part of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) was replaced with 0.52 parts by mass as an antistatic agent. Table 1 shows the results of preparing the product D and performing the same evaluation as in Example 1.

[Example 5]
Both ends of the molecular chain are sealed with vinyl dimethylsiloxy groups, the amount of alkenyl groups is 0.0044 mol / 100 g, the viscosity is 22,000 mPa · s, 9 parts by mass of dimethylpolysiloxane (A2), acetylene black (Denka Black, Denka Co., Ltd.) (D) 3.5 parts by mass was mixed with a planetary mixer for 30 minutes, and then passed through three rolls twice. After returning this to the planetary mixer, 100 parts by mass of dimethylpolysiloxane (A2), both ends of the molecular chain are sealed with trimethylsiloxy groups, and dimethylsiloxane / methylhydrogensiloxane having a silicon atom-bonded hydrogen atom in the side chain. Siloxane (B) (silicon atom-bonded hydrogen atom content = 0.0075 mol / g) 5.2 parts by mass, 1-ethynylcyclohexanol 0.1 parts by mass, platinum chloride acid / 1,3-divinyltetramethyldi 0.22 parts by mass of dimethylpolysiloxane solution (C) containing 1% by mass of siloxane complex as platinum atom content, 15 parts by mass of diatomaceous soil as an inorganic filler, and 20 _{parts by mass of LiN (SO 2} CF ₃ ) _{2 as an antistatic agent.} Table 1 shows the results of preparing the composition E by mixing 0.10 parts of the% adipic acid ester solution (E) at room temperature with a planetary mixer for 30 minutes and performing the same evaluation as in Example 1.

[Example 6]
Both ends of the molecular chain are sealed with vinyldimethylsiloxy groups, 100 parts by mass of dimethylpolysiloxane (A4) having an alkenyl group amount of 0.015 mol / 100 g and a viscosity of 600 mPa · s, acetylene black (Denka Black, manufactured by Denka Co., Ltd.). (D) After mixing 20 parts by mass with a planetary mixer for 30 minutes, the mixture was passed through three rolls twice. After returning this to the planetary mixer, both ends of the molecular chain are further sealed with a trimethylsiloxy group, and the dimethylsiloxane / methylhydrogensiloxane copolymer (B) having a silicon atom-bonded hydrogen atom in the side chain (silicon atom bond). Hydrogen atom content = 0.0075 mol / g) 2.45 parts by mass, 1-ethynylcyclohexanol 0.1 part by mass, platinum chloride acid / 1,3-divinyltetramethyldisiloxane complex as platinum atom content 1 mass 0.20 parts by mass of dimethylpolysiloxane solution (C) containing%, and _{0.025 parts of LiN (SO 2} CF ₃ ) ₂ as antistatic agent in 20% by mass of adipic acid ester solution (E) at room temperature in a planetary mixer. The composition F was prepared by mixing with the mixture for 30 minutes, and the results of the same evaluation as in Example 1 are shown in Table 1.

[Example 7]
In Example 6, the _{composition was the same except that 0.025 part by mass of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) was replaced with 0.5 part by mass as an antistatic agent. Table 1 shows the results of preparing the product G and performing the same evaluation as in Example 1.

[Example 8]
In Example 6, the _{composition was the same except that 0.025 part by mass of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) was replaced with 1.0 part by mass as an antistatic agent. Table 1 shows the results of preparing the product H and performing the same evaluation as in Example 1.

[Example 9]
Both ends of the molecular chain are sealed with vinyldimethylsiloxy groups, the amount of alkenyl groups is 0.015 mol / 100 g, the viscosity is 600 mPa · s, 8 parts by mass of dimethylpolysiloxane (A4), acetylene black (Denka Black, manufactured by Denka Co., Ltd.). (D) After mixing 1.5 parts by mass with a planetary mixer for 30 minutes, the mixture was passed through three rolls twice. After returning this to the planetary mixer, 92 parts by mass of dimethylpolysiloxane (A4), both ends of the molecular chain are sealed with trimethylsiloxy groups, and dimethylsiloxane / methylhydrogensiloxane having a silicon atom-bonded hydrogen atom in the side chain. Copolymer (B) (silicon atom-bonded hydrogen atom content = 0.0075 mol / g) 2.45 parts by mass, 1-ethynylcyclohexanol 0.1 parts by mass, platinum chloride acid / 1,3-divinyltetramethyldi 0.20 parts by mass of dimethylpolysiloxane solution (C) containing 1% by mass of siloxane complex as platinum atom content, 20% by mass of adipic acid ester solution (E) 0 _{of LiN (SO 2} CF ₃ ) _{2 as antistatic agent} .025 parts were mixed at room temperature with a planetary mixer for 30 minutes to prepare a composition Q, and the results of the same evaluation as in Example 1 are shown in Table 1.

[Comparative Example 1]
In Example 1, composition I was prepared with the same formulation except that 0.10 part of a 20% by mass adipate solution (E) _{of LiN (SO 2} CF ₃ ) _{2 was not blended as an antistatic agent.} Table 2 shows the results of the same evaluation as in Example 1.

[Comparative Example 2]
Both ends of the molecular chain are sealed with vinyl dimethylsiloxy groups, the amount of alkenyl groups is 0.0077 mol / 100 g, the viscosity is 7,000 mPa · s, 58 parts by mass of dimethylpolysiloxane (A3), acetylene black (Denka Black, Denka Co., Ltd.) (D) 13 parts by mass was mixed with a planetary mixer for 30 minutes, and then passed through three rolls twice. After returning this to the planetary mixer, 100 parts by mass of dimethylpolysiloxane (A3), both ends of the molecular chain are sealed with trimethylsiloxy groups, and dimethylsiloxane / methylhydrogensiloxane having a silicon atom-bonded hydrogen atom in the side chain. Siloxane (B) (silicon atom-bonded hydrogen atom content = 0.0032 mol / g) 5.2 parts by mass, 1-ethynylcyclohexanol 0.1 parts by mass, platinum chloride acid / 1,3-divinyltetramethyldi A composition obtained by mixing 0.22 parts by mass of a dimethylpolysiloxane solution (C) containing 1% by mass of a siloxane complex as a platinum atom content and 15 parts by mass of diatomaceous soil as an inorganic filler at room temperature with a planetary mixer for 30 minutes. J was prepared. Table 2 shows the results of the same evaluation as in Example 1.

[Comparative Example 3]
_{In Example 1, all the compositions were the same except that 0.1 part of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) was replaced with 0.01 part by mass as an antistatic agent. Table 2 shows the results of preparing the product K and performing the same evaluation as in Example 1.

[Comparative Example 4]
In Example 6, the composition M was prepared with the same formulation except that the 20% by mass adipate ester solution (E) _{of LiN (SO 2} CF ₃ ) _{2 was not blended as an antistatic agent, and the composition M was prepared with Example 1.} Table 2 shows the results of similar evaluations.

[Comparative Example 5]
In Example 6, the _{composition was the same except that 0.025 part by mass of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) was replaced with 0.01 part by mass as an antistatic agent. Table 2 shows the results of preparing the product N and performing the same evaluation as in Example 1.

[Comparative Example 6]
In Example 6, the _{composition O has the same formulation except that 0.025 part by mass of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) is replaced with 5 parts by mass as an antistatic agent. The results of the same evaluation as in Example 1 are shown in Table 2.

[Comparative Example 7]
In Example 6, the _{composition P has the same formulation except that 0.025 part by mass of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) is replaced with 10 parts by mass as an antistatic agent. The results of the same evaluation as in Example 1 are shown in Table 2.

[Comparative Example 8]
_{In Example 9, all the compositions were the same except that 0.025 part by mass of LiN (SO 2} CF ₃ ) ₂ in 20% by mass of the adipate ester solution (E) was replaced with 0.01 part by mass as an antistatic agent. Table 2 shows the results of preparing the product R and performing the same evaluation as in Example 1.

In the examples, the charge attenuation performance was sufficient because all of them contained a sufficient component (E). In comparison, in Comparative Examples 1, 2, 4 containing no component (E) and Comparative Examples 3, 5, and 8 below the lower limit of the component (E), sufficient charge attenuation was not observed. Further, in Comparative Examples 6 and 7 containing an excessive amount of the component (E), the charge attenuation was sufficient, but the compression set became large and unsuitable for use.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any of the above-described embodiments having substantially the same configuration as the technical idea described in the claims of the present invention and having the same effect and effect is the present invention. Is included in the technical scope of.

Claims (5)

1. (A) Liquid organopolysiloxane containing at least two alkenyl groups bonded to a silicon atom in one molecule: 100 parts by mass,
   (B) Organohydrogenpolysiloxane containing hydrogen atoms bonded to at least two silicon atoms in one molecule: The number of hydrogen atoms bonded to silicon atoms contained in the component (B) is the component (A). Amount of 0.5 to 10 per alkenyl group bonded to a silicon atom contained in
   (C) Platinum group metal-based catalyst as an addition reaction catalyst: An amount of 0.5 to 1,000 ppm in terms of platinum group metal with respect to the total mass of the components (A) to (B).
   (D) Carbon material: 1 to 50 parts by mass,
   (E) Antistatic agent containing lithium: an amount of 0.005 to 0.2 parts by mass with respect to the total mass of the components (A) to (B).
   An addition-curable liquid conductive silicone rubber composition, which comprises.
2. The _{component (E), LiBF 4, LiClO 4, LiPF} 6, LiAsF 6, LiSbF 6, LiSO 3 CF 3, LiN (SO 2 CF 3) 2, LiSO 3 C 4 F 9, LiC (SO 2 CF 3) _3. The addition-curable liquid conductive silicone rubber composition according to claim 1, wherein the composition is one or more selected from 3 and LiB (C ₆ H ₅ ) _4.
3. The addition-curable liquid conductive silicone rubber composition according to claim 1 or ₂ , wherein the component (E) is LiN (SO ₂ CF ₃ ) 2.
4. An electrophotographic image-forming member having an elastic layer made of a cured product of the addition-curable liquid conductive silicone rubber composition according to any one of claims 1 to 3.
5. The electrophotographic image forming member according to claim 4, wherein the electrophotographic image forming member is a member selected from a developing roll and a developing belt.