JP3500927B2 - Semiconductive silicone rubber composition and semiconductive silicone rubber roll - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a silicone rubber which is cured to have a stable resistance value in a semiconductive region, and is used in a semiconductive layer such as a charging roll, a transfer roll or a developing roll of an OA device such as a copying machine or a facsimile. TECHNICAL FIELD The present invention relates to a semiconductive silicone rubber composition and a semiconductive silicone rubber roll which are effectively used as a conductive roll material.

[0002]

2. Description of the Related Art Roll materials are one of the rubber materials for office machines.
As the rubber material, various materials such as urethane rubber, ethylene propylene rubber, natural rubber, etc., including silicone rubber, are used, and composite materials of these are also proposed.

These rubber materials have been used for various purposes as an electrically insulating material or as a conductive material containing a conductive material for the purpose of preventing static electricity or an electrical conduction path. Especially 1 × 10 ³ to 1 × 10 ¹² Ω
-Semi-conductive materials in the medium resistance region of cm have come to be used as roll materials for copying machines and the like.

In this case, since the semiconductive roll material controls the current flowing by the resistance value of the rubber material itself in most of the usage environment, the stability of the resistance value is required to have a purpose such as transfer ability. Has become very important. Further, in order to stabilize the current value flowing in the roll material, and further to effectively apply the electric charge on the OPC, 100
A voltage of V to 10 kV is often applied.

Most of such semiconductive roll materials mainly use conductive carbon. For example, in Japanese Patent Laid-Open No. 6-306289, a specific surface area of 25 to 50 m is used.
² / g, DBP oil absorption amount 100 to 150 cc / 100 g,
Furnace carbon black having a toluene color transmission of 90 to 100%, and in JP-A-7-62241,
ΔDBP (DBP oil absorption (JIS K-6221) and DBP oil absorption after compression, which is 24M ₄ DBP oil absorption (AS
Difference from TM-D3493)) 40 to 150 cc / 100
g, Dmod diameter (particle diameter of carbon that has become an aggregate) 25
It is proposed to use furnace carbon of 0 to 400 nm.

However, when these carbons are used as the conductive material, the stability of the conductive material carbon is limited in such a high-voltage use environment, and the carbon-carbon structure is broken. However, there is a problem that when it is used for a long time, it will deviate from the set resistance value due to vaporization of carbon, etc. Especially, the higher the voltage becomes, and the more current flows, the more the above phenomenon appears. There was a problem.

On the other hand, when ordinary conductive carbon black is used, it is known that the relationship between current and voltage becomes non-linear, not according to Ohm's law, due to the tunneling effect of the carbon structure (LKH van). Bee
k and B. I. C. F. van Pul, J.M. A
ppl. Polymer Sci. , 6,651 (19
62)). OP including development roll and transfer roll that must control the resistance of semi-conductive region with high accuracy
As the roll characteristics around C, the non-linearity of these current and voltage is unreasonable. Therefore, as a method for solving this problem, JP-A-6-192486 discloses addition of a phosphoric acid ester, JP-A-63-86205 and JP-A-8-
Although the use of potassium titanate whiskers is described in Japanese Patent No. 120176, it is difficult to say that any of them is sufficient as a solution to the above-mentioned relationship between current and voltage.

The present invention has been made in view of the above circumstances, and can stabilize the resistance value of the roll material even when used under a high voltage, and can make the relationship between the current and the voltage under a high voltage linear. Therefore, it is an object of the present invention to provide a semiconductive silicone rubber composition and a semiconductive silicone rubber roll which can be suitably used as a roll material.

[0009]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies to achieve the above-mentioned object, the present inventor has found that the following average composition formula (1) R ¹ _n SiO _{(4-n) / 2} (1) (in the formula, R ¹ is the same or different monovalent hydrocarbon group, and n is a positive number of 1.98 to 2.02) A silicone rubber composition containing an organopolysiloxane having at least two saturated groups and a curing agent is a thermal black and / or furnace having a primary particle size of 70 nm or more and a DBP oil absorption of 50 cc / 100 g or less. By blending black, it excels in workability and compression set, and can impart stable semi-conductivity to silicone rubber. Moreover, it is stable against changes in resistance even under high voltage and can withstand long-term use. Can be used as roll material for machines Conductive silicone rubber composition was found that the resulting. Here, semiconductive means that the cured silicone rubber has a resistance of 1 × 10 ³ to 1 × 10 ¹² Ω · c.
It is in the range of m.

That is, 100 parts by weight of the organopolysiloxane represented by the above average composition formula (1) (parts by weight, the same applies hereinafter).
With a primary particle size of 70 nm or more and a DBP oil absorption of 50 cc /
By blending 2 to 200 parts of 100 g or less of thermal black and / or furnace black, the resulting silicone rubber composition is an organic peroxide or an organohydrogenpolysiloxane / platinum-based catalyst alone, or an organic peroxide. It can also be cured with a combination system of and the organohydrogenpolysiloxane / platinum-based catalyst, and the resulting molded product shows little change in the resistance value of the conductive material due to the impediment of alteration of the conductive material under high voltage, and long-term use. Therefore, it can be optimally used as a roll material for office machines and the like.

As mentioned above, it is known to use conductive carbon for the semiconductive roll material, and it has been proposed to use furnace carbon black. However, the present inventor used various carbons. Among the blacks, when thermal black and / or furnace black whose primary particle size and DBP oil absorption amount are in the above specific ranges are used, as can be seen from the results of the examples described later, the primary particle size or D
It has been found that a silicone rubber roll having extremely stable resistance changes can be obtained as compared with those having a BP oil absorption outside the above specified range (acetylene black or Ketjen black).

In addition to the organopolysiloxane of formula (1), the following average composition formula (2) R ¹ _a SiO 2 _{(4-a) / 2} (2) (wherein R ² is the same or different type of fat) It is a monovalent hydrocarbon group having no group unsaturated bond, and a is 1.98 to 2.0.
It is a positive number of 2. ), 0.1 to 1 in all R ² groups
By mixing 0.1 to 60 parts by weight of the organopolysiloxane of which 100 mol% is a phenyl group with 100 parts by weight of the organopolysiloxane of the formula (1), the phenyl group-containing organopolysiloxane of the formula (2) can be obtained. The organopolysiloxane of the formula (1) and the above carbon black are intermediary to assist the dispersion of the carbon black, so that the above carbon black can be blended more stably, and therefore the alteration of the conductive silicone rubber under a high voltage. Therefore, the present invention has been accomplished by finding that it is possible to provide a silicone rubber roll that can prevent the occurrence of the above-mentioned phenomenon, reduce the change in resistance value, provide stable semiconductivity, and can sufficiently withstand long-term use.

Accordingly, the present invention provides (A) the following average composition formula (1) R ¹ _n SiO _{(4-n) / 2} (1) (wherein R ¹ is the same or different monovalent hydrocarbon group). And n is a positive number in the range of 1.98 to 2.02), and 100 parts by weight of organopolysiloxane having at least two aliphatic unsaturated groups in the molecule (B) has a primary particle size of 70 nm. The above, and the thermal black and / or furnace black having a DBP oil absorption of 50 cc / 100 g or less 2 to 200 parts (C) curing agent is characterized by containing an amount capable of curing the component (A). Semi-conductive silicone rubber composition, and further (D) the following average compositional formula (2) R ¹ _a SiO _{(4-a) / 2} (2) (wherein R ² is the same or different aliphatic unsaturated bond) Is a monovalent hydrocarbon group having no a, and a is 1.98 to 2.0.
It is a positive number of 2. ), 0.1 to 1 in all R ² groups
Provided are a semiconductive silicone rubber composition containing 0.1 to 60 parts by weight of an organopolysiloxane in which 00 mol% is a phenyl group, and a semiconductive silicone rubber roll obtained by molding and curing these compositions. . In this case, a foaming agent may be added to the above composition to form a silicone rubber sponge.

The present invention will be described in more detail below. The organopolysiloxane as the first essential component of the semiconductive silicone rubber composition according to the present invention is represented by the following average composition formula (1). R ¹ _n SiO _{(4-n) / 2} (1) (In the formula, R ¹ is the same or different monovalent hydrocarbon group, and n is a positive number of 1.98 to 2.02.)

In the above formula, R ¹ is an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group,
Cycloalkyl groups such as cyclohexyl groups, vinyl groups, allyl groups, butenyl groups, alkenyl groups such as hexenyl groups,
From a phenyl group, an aryl group such as a tolyl group, or a chloromethyl group, a trifluoropropyl group, a cyanoethyl group, etc., in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with a halogen atom, a cyano group, etc. The same or different selected monovalent hydrocarbon group preferably having 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, unsubstituted or substituted.
In this case, R ¹ needs to have at least two aliphatic unsaturated groups (alkenyl groups), and the content of the aliphatic unsaturated groups in R ¹ is 0.001 to 20 mol%. In particular, it is preferably 0.025 to 5 mol%. Also,
n is a positive number of 1.98 to 2.02.

The organopolysiloxane of the above formula (1) may be partially branched, but it is basically preferable that it is linear. In addition, one or two with different molecular structures
It may be a mixture of two or more species.

Further, the above-mentioned organopolysiloxane has an average degree of polymerization of 100 to 20,000, particularly 3,000 to 1.
It is preferably 10,000.

The carbon black used as the second essential component of the present invention is a characteristic component of the present invention and has a primary particle size of 70 nm or more and a DBP oil absorption of 50 cc / 100.
Thermal black or furnace black may be used as long as it is not more than g. Here, the thermal black is obtained by high-temperature thermal decomposition with natural gas or acetylene gas, and the furnace black is obtained by partial combustion with natural gas or aromatic oil. The primary particle size is 70 nm
The above condition and the DBP oil absorption of 50 cc / 100 g or less mean that the structure of the carbon black is not developed, that is, the conductivity is low, and such a carbon black is shot under high voltage. The key effect is unlikely to occur, and therefore, the resistance drop under high voltage is small.

Here, the primary particle size is 70 nm or more, preferably 70 to 100 nm, and if it is less than 70 nm, the reduction of the resistance under high voltage becomes large.

The DBP oil absorption is JIS K-62.
21-1982 showing the absorption amount of dibutyl phthalate, 50 cc / 100 g or less, preferably 20
It is ~ 45 cc / 100 g. DBP oil absorption is 50cc
If it exceeds / 100 g, the carbon structure will be overdeveloped and the resistance will drop significantly under high voltage.

Specific examples of such carbon black include HTC20 and HTCSL (produced by Shin Nihon Carbon Co., Ltd.).
Manufactured by Asahi No. 15 and Asahi Thermal (manufactured by Asahi Carbon Co., Ltd.).

The amount of the carbon black compounded is 2 to 20 relative to 100 parts of the first component organopolysiloxane.
It is 0 part, preferably 10 to 100 parts, and this range is suitable for obtaining a semiconductive region. If the addition amount is less than 2 parts, the insulating property becomes almost insulative, and the desired effect is not recognized. If the addition amount exceeds 200 parts, it becomes too conductive or the physical (mechanical) properties deteriorate.

In the present invention, the third essential component curing agent is a known organohydrogenpolysiloxane /
A platinum-based catalyst (curing agent for addition reaction) or an organic peroxide catalyst can be used.

As the platinum-based catalyst, known catalysts can be used, and specifically, platinum element simple substance, platinum compound, platinum complex, chloroplatinic acid, alcohol compound of chloroplatinic acid, aldehyde compound, ether compound, various olefins. And the complex are exemplified. The addition amount of the platinum-based catalyst is preferably in the range of 1 to 2,000 ppm as platinum atom with respect to the organopolysiloxane of the first component.

On the other hand, the organohydrogenpolysiloxane, which may be linear, branched or cyclic, has at least 2, preferably 3 or more SiH groups in one molecule, A polymer having a degree of polymerization of 300 or less is preferable, for example, a diorganopolysiloxane whose end is blocked with a dimethylhydrogensilyl group, a copolymer of a dimethylsiloxane unit with a methylhydrogensiloxane unit and a terminal trimethylsiloxy unit, dimethylhydrogen. A low-viscosity fluid composed of siloxane units (H (CH ₃ ) ₂ SiO _0.5 units) and SiO ₂ units, 1, 3,
5,7-Tetrahydrogen-1,3,5,7-tetramethylcyclotetrasiloxane, 1-propyl-3,
5,7-trihydrogen-1,3,5,7-tetramethylcyclotetrasiloxane, 1,5-dihydrogen-3,7-dihexyl-1,3,5,7-tetramethylcyclotetrasiloxane, etc. Is exemplified.

The addition amount of the organohydrogenpolysiloxane as the curing agent is 50 to 500 hydrogen atoms directly bonded to the silicon atom with respect to the aliphatic unsaturated group (alkenyl group) of the organopolysiloxane of the first component. Mol%
Is desirable.

Examples of the organic peroxide catalyst include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, 2,4-dicumyl peroxide, and 2,5-dimethyl-bis. (2,5-t-butylperoxy) hexane,
Di-t-butyl peroxide, t-butyl perbenzoate, etc. are mentioned. The amount of the organic peroxide catalyst added may be 0.1 to 5 parts with respect to 100 parts of the first component organopolysiloxane.

The composition of the present invention has the following average compositional formula (2) R ¹ _a SiO 2 _{(4-a) / 2} (2) (wherein R ² is the same or different aliphatic unsaturated bond). It is a monovalent hydrocarbon group that does not have, and a is 1.98 to 2.0.
It is a positive number of 2. ), 0.1 to 1 in all R ² groups
It is preferable to blend an organopolysiloxane in which 00 mol% is a phenyl group. It is considered that the phenyl group-containing organopolysiloxane has a function of mediating the carbon black and the silicone rubber in the silicone rubber to help disperse the carbon black and stably blend the carbon black.

[0029] In the above formula (2), the R ^2, there may be mentioned the same groups as R ¹ containing no aliphatic unsaturated bond, from 0.1 to 100 mol% of all R ² groups, preferably 1
~ 50 mol%, more preferably 2 to 30 mol% are phenyl groups. When the phenyl group content is less than 0.1 mol%,
The compounding effect of this organopolysiloxane is not exhibited.

The end of this organopolysiloxane may be a triorganosilyl group such as a trimethylsilyl group or a dimethylvinylsilyl group, or a silanol group.

A is a positive number of 1.98 to 2.02, and it is preferable that the organopolysiloxane is basically linear, but one or a mixture of two or more having different molecular structures. May be

The organopolysiloxane of the above formula (2) may be in the form of oil or raw rubber and has an average degree of polymerization of 2 to
It is preferably 20,000, particularly preferably 3 to 10,000.

The compounding amount of the phenyl group-containing organopolysiloxane of the formula (2) is 0.1 to 60 parts, preferably 1 part with respect to 100 parts of the first component organopolysiloxane.
~ 40 parts. If the blending amount is less than 0.1 part, the blending effect will not be exhibited, and if it exceeds 60 parts, the physical properties such as impact resilience will be impaired.

The silicone rubber composition according to the present invention includes
In addition to the above-mentioned essential components, a reinforcing silica powder may be added as an optional component as long as it does not impair the effects of the present invention. The reinforcing silica powder is added in order to obtain a silicone rubber having excellent mechanical strength, and for this purpose, a specific surface area of 50 m ² / g or more, especially 10
It is preferably 0 to 300 m ² / g. If the specific surface area is less than 50 m ² / g, the mechanical strength of the cured product may decrease. Examples of such reinforcing silica powder include fumed silica and precipitated silica, and those whose surface is made hydrophobic with chlorosilane or hexamethyldisilazane are also preferably used.

The amount of the reinforcing silica powder added is 5 to 70 parts based on 100 parts of the first component organopolysiloxane.
In particular, it is preferably 10 to 50 parts, and if it is less than 5 parts, the reinforcing effect may not be obtained because the addition amount is too small,
If it exceeds 70 parts, the workability may deteriorate and the mechanical strength may decrease.

Further, as an optional component, a conductive material such as other conductive inorganic oxide such as conductive zinc white, or a filler such as silicone rubber powder, red iron oxide, ground quartz, calcium carbonate, etc. may be added as an extender. Good.

Further, an inorganic or organic foaming agent for molding a sponge may be added as an optional component. Specifically as this foaming agent, azobisisobutyronitrile,
Examples include dinitropentamethylenetetramine, benzenesulfone hydrazide, azodicarbonamide,
The addition amount is preferably in the range of 1 to 10 parts with respect to 100 parts of the silicone rubber compound. By thus adding the foaming agent to the composition of the present invention, a sponge-like silicone rubber can be obtained.

If desired, various additives such as a colorant and a heat resistance improver, a reaction control agent, a release agent, and a filler dispersant may be added to the composition of the present invention. ,
In particular, diphenylsilane diol, various alkoxy silanes, carbon functional silanes, silanol group-containing low molecular weight siloxanes and the like used as filler dispersants may be added in a minimum amount so as not to impair the effects of the present invention. preferable.

Further, in order to impart flame retardancy and fire resistance to the silicone rubber composition of the present invention, platinum-containing material, platinum compound and titanium dioxide, platinum and manganese carbonate, platinum and γ-F.
Known additives such as e ₂ O ₃ , ferrite, mica, glass fiber and glass flakes may be added.

The silicone rubber composition according to the present invention is prepared by uniformly mixing the above-mentioned components using a rubber kneader such as a two-roll, Banbury mixer, dough mixer (kneader), etc. It can be obtained by applying.

The thus-obtained silicone rubber composition can be molded into various uses by various molding methods such as mold pressure molding and extrusion molding. In particular, it can be molded into a silicone rubber roll. It can be used preferably. The curing can be appropriately selected depending on the curing method and the thickness of the molded product, but usually 1 at 80 to 400 ° C.
It can be performed under the condition of 0 seconds to 30 days. In this silicone rubber roll, a core metal is usually coated with the semiconductive silicone rubber layer to form the semiconductive silicone rubber layer.

[0042]

INDUSTRIAL APPLICABILITY The semiconductive silicone rubber composition of the present invention is used under high voltage by blending thermal black and / or furnace black having a specific primary particle size and DBP oil absorption. A roll material for office machines, etc., which is stable against changes in the resistance value of the roll material and which can withstand long-term use under high voltage, especially 1 ×
It is effective as a semi-conductive silicone rubber roll material having a specific resistance value of 10 ³ to 1 × 10 ¹² Ω · cm, and can be suitably used for a charging roll, a transfer roll and a developing roll.

[0043]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, parts are parts by weight.

[Examples 1 and 2] Dimethylsiloxane unit 99.825 mol%, methylvinylsiloxane unit 0.
15 mol%, dimethylvinylsiloxane unit 0.025
100 parts by weight of rubber-like organopolysiloxane having an average degree of polymerization of about 5,000 and a primary particle size of 80 n
Furnace carbon black HTC20 (manufactured by Shin Nihon Carbon Co., Ltd.) having m and DBP oil absorption of 30 cc / 100 g was blended with rolls in the blending amounts shown in Table 1.

Perbutyl BH (manufactured by Shin-Etsu Chemical Co., Ltd.) as a curing agent was added to 100 parts of the above base compound.
8 parts, 1.5 parts of azobisisobutyronitrile (manufactured by Shin-Etsu Chemical Co., Ltd.) as a foaming agent were added, and the surface was primer 101A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) using a 40 mm extruder. ) Was extruded at the same time as the 6 mm core metal, and then treated at 200 ° C. for 30 minutes to obtain a foam roll. This roll was polished to a diameter of 12 mm using a polishing machine to obtain a semiconductive sponge roll.

The sponge roll 1 thus obtained was sandwiched between the electrodes 2 and 2 as shown in FIG. 1, and the resistance value between the cored bars 3 and 3 was measured at applied voltages of 100 V, 1,000 V and 4,000 V. A trek was used as the measuring device 4. The results are shown in Table 1.

[Example 3] A rubbery phenyl compound having 85.0 mol% of dimethylsiloxane units and 15.0 mol% of diphenylsiloxane units in addition to the base compound of Example 1 and having an average degree of polymerization of about 5,000. A roll was prepared in the same manner as in Example 1 except that 10 parts of the group-containing organopolysiloxane was blended, and the resistance value was measured. The results are shown in Table 1.

[Comparative Examples 1 and 2] As a comparative example, the primary particle size was 4
A roll was prepared in the same manner as in the above example using 0 nm and acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) having a DBP oil absorption of 110 cc / 100 g, and the resistance value was measured. The results are shown in Table 1.

[0049]

[Table 1]

Example 4 Dimethylsiloxane Unit 9
9.825 mol%, methyl vinyl siloxane unit 0.1
100 parts of a rubber-like organopolysiloxane having 5 mol% and 0.025 mol% of dimethylvinylsiloxane units and an average degree of polymerization of about 5,000 was added to a terminal silanol group dimethylpolysiloxane (degree of polymerization n = 1 as a dispersant).
0) 4 parts and 20 parts of treated silica (manufactured by Nippon Aerosil Co., Ltd.) having a specific surface area of 200 m ² / g were added,
A base compound was prepared by heat treatment at ℃ for 2 hours.

Furnace carbon black Asahi No. 15 (Asahi Carbon Co., Ltd.) having a primary particle size of 120 nm and a DBP oil absorption of 40 cc / 100 g per 100 parts of the base compound.
Compound) was added to prepare a compound.

100 parts of the above compound was kneaded with 0.5 part of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as a curing agent, and the resulting compound was used to obtain a diameter of 12 mm (aluminum). A roll having a core metal, a diameter of 6 mm, and a rubber wall thickness of 3 mm was compression-molded. Molding temperature is 1
The molding pressure was 65 ° C./10 minutes, and the molding pressure was 35 kgf / cm ² .

Using the obtained roll, the resistance value was measured in the same manner as in the above example. The results are shown in Table 2.

Comparative Example 3 Instead of the carbon black used in Example 4, the primary particle size was 30 nm and the DBP oil absorption was 3
A roll was obtained in the same manner as in Example 3 except that 8 parts of 80 cc / 100 g of conductive carbon Ketjen Black EC (manufactured by Lion Corporation) was used.

Using the obtained roll, the resistance value was measured in the same manner as in the above example. The results are also shown in Table 2.

[0056]

[Table 2]

[Examples 5 and 6] Dimethylsiloxane unit 99.825 mol%, methylvinylsiloxane unit 0.
15 mol%, dimethylvinylsiloxane unit 0.025
100 parts by weight of a rubbery organopolysiloxane having an average degree of polymerization of about 5,000 and having a silanol group at the terminal silanol group (degree of polymerization n = 1) as a dispersant.
0) 4 parts and 20 parts of treated silica (manufactured by Nippon Aerosil Co., Ltd.) having a specific surface area of 200 m ² / g were added,
A base compound was prepared by heat treatment at ℃ for 2 hours.

Furnace carbon black Asahi No. 15 (Asahi Carbon Co., Ltd.) having a primary particle size of 120 nm and a DBP oil absorption of 40 cc / 100 g per 100 parts of the above base compound.
Manufactured by the present invention, and 1 part of phenylmethylsiloxane represented by the following formula (3) or 1 part of dimethylsiloxane represented by the following formula (4) was added to prepare a compound.

In 100 parts of the above compound, 0.5 part of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane as a curing agent and KEP-13 as a foaming agent (manufactured by Shin-Etsu Chemical Co., Ltd.) Was added in an amount of 3 parts, and the obtained compound was extruded and foamed in the same manner as above to obtain a semiconductive sponge roll. The electrical resistance of the obtained sponge roll was measured in the same manner as above. The results are shown in Table 3.

[0060]

[Chemical 1]

[0061]

[Table 3]

From the results of Tables 1 to 3, it was confirmed that the silicone rubber roll formed of the cured product of the semiconductive silicone rubber composition of the present invention can impart a stable semiconductive region.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an apparatus for measuring the resistance of a semiconductive silicone rubber.

[Explanation of symbols]

1 Semi-conductive silicone rubber 2 electrodes 3 core 4 measuring equipment

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G03F 7/30 501 G03F 7/30 501 (56) Reference JP-A-7-21510 (JP, A) JP-A-9-222770 (JP, A) JP 10-195297 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 83/00-83/16 C08K 3/00-13/08

Claims (5)

(57) [Claims] 1. (A) The following average composition formula (1) R ¹ _n SiO _{(4-n) / 2} (1) (wherein R ¹ is the same or different monovalent hydrocarbon group, and n Is a positive number of 1.98 to 2.02), and 100 parts by weight of organopolysiloxane having at least two aliphatic unsaturated groups in the molecule (B) has a primary particle size of 70 nm or more, And, the DBP oil absorption amount is 50 cc / 100 g or less, thermal black and / or furnace black 2 to 200 parts by weight (C) curing agent It is characterized by containing an amount capable of curing the component (A). Silicone rubber composition. 2. Further, (D) the following average composition formula (2) R ¹ _a SiO 2 _{(4-a) / 2} (2) (wherein R ² has the same or different aliphatic unsaturated bond) A monovalent hydrocarbon group, and a is 1.98 to 2.0
It is a positive number of 2. ), 0.1 to 1 in all R ² groups
The semiconductive silicone rubber composition according to claim 1, wherein 0.1 to 60 parts by weight of an organopolysiloxane in which 00 mol% is a phenyl group is blended. 3. (E) Specific surface area (BET method) 50 m
^The semiconductive silicone rubber composition according to claim 1 or 2, wherein 5 to 70 parts by weight of the reinforcing silica powder of ² / g or more is added. 4. The semiconductive silicone rubber composition according to claim 1, 2 or 3 further comprising (F) 1 to 10 parts by weight of a foaming agent. 5. A semiconductive silicone rubber roll obtained by molding and curing the semiconductive silicone rubber composition according to claim 1.