CA2090597A1 - Electrically conductive silicone rubber composition for application to rolls - Google Patents
Electrically conductive silicone rubber composition for application to rollsInfo
- Publication number
- CA2090597A1 CA2090597A1 CA 2090597 CA2090597A CA2090597A1 CA 2090597 A1 CA2090597 A1 CA 2090597A1 CA 2090597 CA2090597 CA 2090597 CA 2090597 A CA2090597 A CA 2090597A CA 2090597 A1 CA2090597 A1 CA 2090597A1
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- Canada
- Prior art keywords
- silicone rubber
- electrically conductive
- weight parts
- component
- rubber composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K9/00—Use of pretreated ingredients
- C08K9/04—Ingredients treated with organic substances
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/04—Carbon
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/12—Polysiloxanes containing silicon bound to hydrogen
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/14—Polymer mixtures characterised by other features containing polymeric additives characterised by shape
- C08L2205/18—Spheres
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
- Electrophotography Configuration And Component (AREA)
Abstract
ABSTRACT
The present invention relates to an electrically conductive silicone rubber composition for application to rolls. More specifically, the present invention relates to a conductive silicone rubber composition for roll applications that exhibits little tack prior to its cure and that cures to give a silicone rubber molding that has an excellent processability (grindability, etc.), low surface tack, and narrow range of variation in volume resistivity values.
The present invention relates to an electrically conductive silicone rubber composition for application to rolls. More specifically, the present invention relates to a conductive silicone rubber composition for roll applications that exhibits little tack prior to its cure and that cures to give a silicone rubber molding that has an excellent processability (grindability, etc.), low surface tack, and narrow range of variation in volume resistivity values.
Description
3 ~ 7 ELECTRICALLY C~ND~CTIVE S r LICONE RUBBER COMPOSITION
FOR APPLICATION TO ROLLS
The present invention relates to an electrically conductive silicone rubber composition for application to rolls. More specifically, the present invention relates to a conductive silicone rubber composition for roll applications that exhibits little tack prior to its cure and that cures to give a silicone rubber molding that has an excellent processability (grindability, etc.), low surface tack, and narrow range of variation in volume resistivity values.
Silicone rubbers are used as roll coverings in copiers, facsimile machines, printers, etc., due to their excellent stability with respect to the various operating environments, excellent resistance to compression set, and so forth. In the case of the charging rolls, developing rolls, transfer rolls, etc., used in contact developing devices, conduc-tive carbon black-containing silicone rubber compositions are employed that cure to give a low-hardness silicone ruhber molding with a volume resistivity in the conduction region of approximately 104 to l0l ohm-cm.
However, the roll coverings molded from such silicone rubber compositions have an elevated tack. Moreover, it is difficult to obtain a low surface roughness by grinding their surface. As a consequence, these roll coverings are not entirely satisfactory. In other words, roll coverings of this type preferably have a low tack and low surface roughness because these characteristics ~upport inhibition of toner (developer) pick-up by the roll surface and support the development ~?t~
of consistent toner transfer characteristics. However, in order to prepare a conductive carbon black-containing silicone rubber composition that will cure to give a low-hardness silicone rubber molding, the composition must contain only small quantities of reinforcing filler and must develop a low crosslink density. Roll coverings molded from such compositions necessarily have a high tack and also have a poor grindability. In addition, such silicone rubber compositions also have a high tack prior to their cure, and this causes a problematic roll workability during kneading on, for example, a two-roll.
The present invention solves the problems of the prior art by introduction of a conductive silicone rubber composition for roll applications that has a low tack and excellent roll workability prior to its cure and that cures to give a roll covering that exhibits an excellent processability (grindability, etc.), low surface tack, and a narrow range of volume resistivity values.
The present invention relates to an electrically conductive silicone rubber composition for roll applications comprising:
(A) 100 weight parts organopolysiloxane that contains in each molecule at least 2 siloxane units with the following general formula R aR bSi(4-a-b)/2 where R represents monovalent hydrocarbon groups lacking aliphatically unsaturated ~onds, R2 represents alkenyl, a is a number with a value of zero to 2, b is a number with a value of 1 to 2, and a + b = 1.95 to 2.10, (B) 5 to 100 weight parts surfactant-treated inorganic r~ rJ
filler, (C) 5 to 50 weight parts electrically conductive carbon black, (D) 15 to 200 weight parts spherical silicone rubber powder whose average particle size is 0.5 to 30 micrometers, and (E) curing agent in a quantity sufficient to cure the present composition.
To explain the preceding in greater detail, the component (A) used by the present invention comprises organopolysiloxane that contains at least 2 alkenyl groups in each molecule. This is the main or base component of the present invention. The group Rl in the preceding formula comprises alkyl groups such as methyl, ethyl, and propyl; aryl groups such as phenyl and tolyl; and substituted alkyl groups such as 3,3,3-trifluoropropyl and 3-chloropropyl. The group R2 comprises alkenyl groups such as vinyl, allyl, propenyl, and so forth. Finally, a has a value of 0 to 2, b has a value of 1 to 2, and a + b has a value of 1.95 to 2.10. The molecular structure of this component may be straight-chain or branch-containing straight chain. The molecular weight of this component is not specifically restricted, and this component may range from a low-viscosity ~luid to a high-viscosity gum.
Component (B) comprises surfactant-treated inorganic filler, and it is this component that functions to stabilize the volume resistivity of the composition of the present invention and provide consistent volume resistivity values. The surfactant in this case comprises known surfactants and is not specifically restricted in scope, but cationic surfactants are preferred. The inorganic filler is 3 ) ~ ~
exemplified by silica micropowders, e.g., wet-method silica, dry-method silica, etc., diatomaceous earth, alumina, and so forth, and the silica micropowders are preferred. This component can be prepared, for example, ~a) by mixi}lg the inorganic filler and surfactant to homogeneity and then heat-treating the mixture or (b) by mixing the inorganic filler with an aqueous solution of the surfactant and then drying off the water fraction. Each 100 weight parts inorganic filler is preferably treated with 0.05 to 10 weight parts surfactant.
The electrically conductive carbon black comprising component (C) is the component that confers conductivity on the composition of the present invention. This component is not particularly restricted, and as a general matter comprises those carbon blacks that have heretofore been used to confer sonductivity on silicone rubber compositions. Such carbon blacks are exemplified by acetylene blacks, furnace blacks, thermal blacks, and so forth. Among these, carbon blacks with an oil absorption of 50 to 150 mg/lOOg are preferred.
Silicone ruhber powder comprises the component (D) used in the present invention, and it is this component that characteriæes or distinguishes the composition under consideration. This componen-t provides the composition of the present invention with a low tack as well as with processability (grindability, etc.). Even at a high fill ratio, this silicone rubber powder causes a much smaller increase in the hardness of the silicone rubber molding than the conventional inorganic fillers used as fillers for silicone rubber compositions. As a consequence, this ~ ~ t'~ ~f3~ 7 component functions to reduce the surface tack of the silicone rubber molding while at the same time improving the rubber processing characteristics, e.g., grindability, roll workability, etc. The particle diameter of this silicone rubber powder should fall within the range of 0.5 to 30 micrometers, and it must have a spherical morphology. This silicone rubber powder can be prepared, for example, by the following methods: (i) curing a ]iquid addition-reaction-curing silicone rubber composition by spraying it into hot air (refer to Japanese Patent Application Laid Open lKokai or Unexamined~ Numbers Sho 63-17959 ~17,959/1988} and Sho 63-77942 ~77,942/1988]}; (ii) dispersing a liquid condensation-reaction-curing silicone rubber composition as the discontinuous phase in water or surfactant-containing water, and then removing the water fraction while curing into the silicone rubber by spraying into hot air or by heating (refer to Japanese Patent Application Laid Open Number Sho 63-202658 ~202,658/1988~).
As is known, silicone rubber powder can also be prepared by mechanically grinding a silicone rubber cured by some method other than those outlined above.
However, the silicone rubber powder afforded by this method has an irregular particle morphology and an average particle diameter generally of at least 100 micrometers. In the case of silicone rubber moldings prepared using this type of silicone rubber powder, the surface tack and surface grindability are not substantially improved, and in fact these characteristics become highly variable or inconsistent.
This component should be added at 15 to 200 weight parts per 100 weight parts component (A) and preferably at 20 to 150 weight parts per 100 ~eight parts component (~).
The curing agent comprising component (E) is the component that cures the composition of the present invention. This component will generally be an organoperoxide, but the combination of an organohydrogenpolysiloxane and a platinum group metal compound catalyst may also be used. This component should be added in a ~uantity sufficien-t to induce curing of the composition of the present invention. In the case of organoperoxides, this will generally be 0.1 to 10 weight parts per 100 weight parts component (A).
In the case of the combination of an organohydrogenpolysiloxane and platinum group metal compound catalyst, the organohydrogenpolysiloxane should be used generally at 0.5 to 20 weight parts per 100 weight parts component (A) and the platinum group metal compound catalyst should be used at 0.1 to lO0 weight parts for each 1,000,000 weight parts component (A).
The composition of the present invention is readily prepared simply by mixing the above-described components (A~ through (E) to homogeneity. Insofar as the object of the present invention is not compromised, the composition of the present invention may contain the various additives known in the art, for example, heat stabilizers, flame retardants, adhesion promoters, and so forth.
The present invention is explained in greater detail below through illustrative examples. In the examples, parts designates weight parts, and the viscosity is the value at 25C.
Example 1. A mixture (a) was prepared by mixing 6 parts trimethylsiloxy-endblocked methylhydrogenpolysiloxane (viscosity = 10 centipoise (0.01 Pa.s), silicon-bonded hydrogen content = 1.5 weight %) into 100 parts dimethylvinylsiloxy-endblocked dimethylpolysiloxane (viscosity = 500 centipoise (0.5 Pa.s), vinyl content = 0.5 weight %). A mixture (b) was also prepared by mixing 0.6 parts isopropanolic chloroplatinic acid solution (platinum content = 3 weight %) into 100 parts of the same type of dimethylpolysiloxane as described above. The 1 : 1 (weight) mixture of mixtures (a) and (b) was transferred to a colloid mill, and the water-based dispersion of a silicone rubber composition was prepared by the simultaneous addition of ion-exchanged water and surfactant. This silicone rubber composition water-based dispersion was sprayed into a spray drier operating at 200C. Removal of the water simultaneous with curing of the silicone rubber composition afforded a spherical silicone rubber powder with average particle diameter = 10 micrometers.
A mixture was then prepared from lO0 parts water, 10 parts surfactant (stearyltrimethylammonium chloride), and wet-method silica with a BET surface of 130 m /g. This mixture was dried by spraying into a spray drier operating at 200C to give a wet-method silica whose surface was treated with surfactant.
A silicone rubber base was prepared by mixing the following to homogeneity in a kneader mixer: 15 parts of the surfactant-treated wet-method silica prepared as above, 25 parts furnace black with an oil absorption of 80 mg/100 g, and 100 parts dimethylpolysiloxane gum (average degree of ~ .t~s~
polymerization = 3,000) composed of 99.84 mole %
dimethylsiloxane unit and 0.16 mole%
methylvinylsiloxane unit.
The spherical silicone rubber powder prepared as above (quantity reported in Table 1 below) and l.0 part 2,5-dimethylbis(2,5-tert-butylperoxy)hexane were simultaneously added to 100 parts of the preceding silicone rubber base with mixing to homogeneity on a two-roll. The respective products were conductive silicone rubber compositions 1 - 3 for roll applications.
Each of compositions 1 - 3 was press molded for 10 minutes at 170C/25 kgf/cm2 to give 5 sheet moldings (thickness = 2 mm). In addition, each of compositions 1 - 3 was wrapped onto a stainless steel roll core (diameter = 5 mm), and the respective silicone rubber-covered rolls (diameter = 15 mm) were prepared by vulcanization and bonding for 10 minutes at 170C.
In each case, the silicone rubber sheets and silicone rubb~r-covered roll were also held for 4 hours in a hot air-circulation oven maintained at 200C.
Each silicone rubber-covered roll with diameter = 15 mm was ground to a diameter of 14 mm using a cylindrical grinder. The roughness was measured on the surface of the resulting silicone rubber-covered roll, and these measurement results are reported in Table 2. The volume resistivity was measured on the sheets in order to evaluate the variation in this value, and these measurement results are also reported in Table 2 below.
Comparison Examples 2 and 3. In Comparison Example 2 (composition 4), silicone rubber sheets and a silicone rubber-covered roll were prepared as in Example 1, but in this case using 10 parts of the silicone rubber powder used in Example 1. In Comparison Example 3 (composition 5), silicone rubber sheets and a silicone rubber-covered roll were prepared as in Example 1, but in this case omitting the silicone rubber powder used in Example 1. The properties of the obtained silicone rubber sheets and silicone rubber-covered rolls were measured as in Example 1, and these results are reported in Tables 1 and 2.
Table 1 Present invention Comparison examples compo- compo- compo- compo- compo-components sition sition sition si4tion sition __ _ silicon 140 140 140 140 140 rubber base (parts) _ _ _ silicon 20 50 150 10 0 ruhber po~der (parts)L_____ _____ _ __ 2~ 3~7 Table 2 ____ _._ Present ~nvention Comparison examples ~easurement compo- compo- compo- compo- compo-valuPs sition sition 6i3tion sition sition ____ __ __ ___ _ .. __ range of variation 7 7 7 7 7 in the volumeI x 10 I x 10 I x 10 1 x 10 I x 10 resistivity values to 7 to 7 to 7 to 7 to 7 ~ohm-cm) 3 x 10 2 x 10 2 x 10 3 x 10 2 x 10 roughness of the roll surface 5 3 3 10 13 R~ ~m~crometers) _ __ ____ ____ ~_~
hardness ~JIS ~) 38 37 36 38 38 tack durlng ~_ +. ____ x xx 2-roll kneading _ ____ ++ : no tack observed, roll workability is very good + : minor degree of tack, roll workability is good x : tack present, roll workability is poor xx : substantial tack observed, roll workability is very poor
FOR APPLICATION TO ROLLS
The present invention relates to an electrically conductive silicone rubber composition for application to rolls. More specifically, the present invention relates to a conductive silicone rubber composition for roll applications that exhibits little tack prior to its cure and that cures to give a silicone rubber molding that has an excellent processability (grindability, etc.), low surface tack, and narrow range of variation in volume resistivity values.
Silicone rubbers are used as roll coverings in copiers, facsimile machines, printers, etc., due to their excellent stability with respect to the various operating environments, excellent resistance to compression set, and so forth. In the case of the charging rolls, developing rolls, transfer rolls, etc., used in contact developing devices, conduc-tive carbon black-containing silicone rubber compositions are employed that cure to give a low-hardness silicone ruhber molding with a volume resistivity in the conduction region of approximately 104 to l0l ohm-cm.
However, the roll coverings molded from such silicone rubber compositions have an elevated tack. Moreover, it is difficult to obtain a low surface roughness by grinding their surface. As a consequence, these roll coverings are not entirely satisfactory. In other words, roll coverings of this type preferably have a low tack and low surface roughness because these characteristics ~upport inhibition of toner (developer) pick-up by the roll surface and support the development ~?t~
of consistent toner transfer characteristics. However, in order to prepare a conductive carbon black-containing silicone rubber composition that will cure to give a low-hardness silicone rubber molding, the composition must contain only small quantities of reinforcing filler and must develop a low crosslink density. Roll coverings molded from such compositions necessarily have a high tack and also have a poor grindability. In addition, such silicone rubber compositions also have a high tack prior to their cure, and this causes a problematic roll workability during kneading on, for example, a two-roll.
The present invention solves the problems of the prior art by introduction of a conductive silicone rubber composition for roll applications that has a low tack and excellent roll workability prior to its cure and that cures to give a roll covering that exhibits an excellent processability (grindability, etc.), low surface tack, and a narrow range of volume resistivity values.
The present invention relates to an electrically conductive silicone rubber composition for roll applications comprising:
(A) 100 weight parts organopolysiloxane that contains in each molecule at least 2 siloxane units with the following general formula R aR bSi(4-a-b)/2 where R represents monovalent hydrocarbon groups lacking aliphatically unsaturated ~onds, R2 represents alkenyl, a is a number with a value of zero to 2, b is a number with a value of 1 to 2, and a + b = 1.95 to 2.10, (B) 5 to 100 weight parts surfactant-treated inorganic r~ rJ
filler, (C) 5 to 50 weight parts electrically conductive carbon black, (D) 15 to 200 weight parts spherical silicone rubber powder whose average particle size is 0.5 to 30 micrometers, and (E) curing agent in a quantity sufficient to cure the present composition.
To explain the preceding in greater detail, the component (A) used by the present invention comprises organopolysiloxane that contains at least 2 alkenyl groups in each molecule. This is the main or base component of the present invention. The group Rl in the preceding formula comprises alkyl groups such as methyl, ethyl, and propyl; aryl groups such as phenyl and tolyl; and substituted alkyl groups such as 3,3,3-trifluoropropyl and 3-chloropropyl. The group R2 comprises alkenyl groups such as vinyl, allyl, propenyl, and so forth. Finally, a has a value of 0 to 2, b has a value of 1 to 2, and a + b has a value of 1.95 to 2.10. The molecular structure of this component may be straight-chain or branch-containing straight chain. The molecular weight of this component is not specifically restricted, and this component may range from a low-viscosity ~luid to a high-viscosity gum.
Component (B) comprises surfactant-treated inorganic filler, and it is this component that functions to stabilize the volume resistivity of the composition of the present invention and provide consistent volume resistivity values. The surfactant in this case comprises known surfactants and is not specifically restricted in scope, but cationic surfactants are preferred. The inorganic filler is 3 ) ~ ~
exemplified by silica micropowders, e.g., wet-method silica, dry-method silica, etc., diatomaceous earth, alumina, and so forth, and the silica micropowders are preferred. This component can be prepared, for example, ~a) by mixi}lg the inorganic filler and surfactant to homogeneity and then heat-treating the mixture or (b) by mixing the inorganic filler with an aqueous solution of the surfactant and then drying off the water fraction. Each 100 weight parts inorganic filler is preferably treated with 0.05 to 10 weight parts surfactant.
The electrically conductive carbon black comprising component (C) is the component that confers conductivity on the composition of the present invention. This component is not particularly restricted, and as a general matter comprises those carbon blacks that have heretofore been used to confer sonductivity on silicone rubber compositions. Such carbon blacks are exemplified by acetylene blacks, furnace blacks, thermal blacks, and so forth. Among these, carbon blacks with an oil absorption of 50 to 150 mg/lOOg are preferred.
Silicone ruhber powder comprises the component (D) used in the present invention, and it is this component that characteriæes or distinguishes the composition under consideration. This componen-t provides the composition of the present invention with a low tack as well as with processability (grindability, etc.). Even at a high fill ratio, this silicone rubber powder causes a much smaller increase in the hardness of the silicone rubber molding than the conventional inorganic fillers used as fillers for silicone rubber compositions. As a consequence, this ~ ~ t'~ ~f3~ 7 component functions to reduce the surface tack of the silicone rubber molding while at the same time improving the rubber processing characteristics, e.g., grindability, roll workability, etc. The particle diameter of this silicone rubber powder should fall within the range of 0.5 to 30 micrometers, and it must have a spherical morphology. This silicone rubber powder can be prepared, for example, by the following methods: (i) curing a ]iquid addition-reaction-curing silicone rubber composition by spraying it into hot air (refer to Japanese Patent Application Laid Open lKokai or Unexamined~ Numbers Sho 63-17959 ~17,959/1988} and Sho 63-77942 ~77,942/1988]}; (ii) dispersing a liquid condensation-reaction-curing silicone rubber composition as the discontinuous phase in water or surfactant-containing water, and then removing the water fraction while curing into the silicone rubber by spraying into hot air or by heating (refer to Japanese Patent Application Laid Open Number Sho 63-202658 ~202,658/1988~).
As is known, silicone rubber powder can also be prepared by mechanically grinding a silicone rubber cured by some method other than those outlined above.
However, the silicone rubber powder afforded by this method has an irregular particle morphology and an average particle diameter generally of at least 100 micrometers. In the case of silicone rubber moldings prepared using this type of silicone rubber powder, the surface tack and surface grindability are not substantially improved, and in fact these characteristics become highly variable or inconsistent.
This component should be added at 15 to 200 weight parts per 100 weight parts component (A) and preferably at 20 to 150 weight parts per 100 ~eight parts component (~).
The curing agent comprising component (E) is the component that cures the composition of the present invention. This component will generally be an organoperoxide, but the combination of an organohydrogenpolysiloxane and a platinum group metal compound catalyst may also be used. This component should be added in a ~uantity sufficien-t to induce curing of the composition of the present invention. In the case of organoperoxides, this will generally be 0.1 to 10 weight parts per 100 weight parts component (A).
In the case of the combination of an organohydrogenpolysiloxane and platinum group metal compound catalyst, the organohydrogenpolysiloxane should be used generally at 0.5 to 20 weight parts per 100 weight parts component (A) and the platinum group metal compound catalyst should be used at 0.1 to lO0 weight parts for each 1,000,000 weight parts component (A).
The composition of the present invention is readily prepared simply by mixing the above-described components (A~ through (E) to homogeneity. Insofar as the object of the present invention is not compromised, the composition of the present invention may contain the various additives known in the art, for example, heat stabilizers, flame retardants, adhesion promoters, and so forth.
The present invention is explained in greater detail below through illustrative examples. In the examples, parts designates weight parts, and the viscosity is the value at 25C.
Example 1. A mixture (a) was prepared by mixing 6 parts trimethylsiloxy-endblocked methylhydrogenpolysiloxane (viscosity = 10 centipoise (0.01 Pa.s), silicon-bonded hydrogen content = 1.5 weight %) into 100 parts dimethylvinylsiloxy-endblocked dimethylpolysiloxane (viscosity = 500 centipoise (0.5 Pa.s), vinyl content = 0.5 weight %). A mixture (b) was also prepared by mixing 0.6 parts isopropanolic chloroplatinic acid solution (platinum content = 3 weight %) into 100 parts of the same type of dimethylpolysiloxane as described above. The 1 : 1 (weight) mixture of mixtures (a) and (b) was transferred to a colloid mill, and the water-based dispersion of a silicone rubber composition was prepared by the simultaneous addition of ion-exchanged water and surfactant. This silicone rubber composition water-based dispersion was sprayed into a spray drier operating at 200C. Removal of the water simultaneous with curing of the silicone rubber composition afforded a spherical silicone rubber powder with average particle diameter = 10 micrometers.
A mixture was then prepared from lO0 parts water, 10 parts surfactant (stearyltrimethylammonium chloride), and wet-method silica with a BET surface of 130 m /g. This mixture was dried by spraying into a spray drier operating at 200C to give a wet-method silica whose surface was treated with surfactant.
A silicone rubber base was prepared by mixing the following to homogeneity in a kneader mixer: 15 parts of the surfactant-treated wet-method silica prepared as above, 25 parts furnace black with an oil absorption of 80 mg/100 g, and 100 parts dimethylpolysiloxane gum (average degree of ~ .t~s~
polymerization = 3,000) composed of 99.84 mole %
dimethylsiloxane unit and 0.16 mole%
methylvinylsiloxane unit.
The spherical silicone rubber powder prepared as above (quantity reported in Table 1 below) and l.0 part 2,5-dimethylbis(2,5-tert-butylperoxy)hexane were simultaneously added to 100 parts of the preceding silicone rubber base with mixing to homogeneity on a two-roll. The respective products were conductive silicone rubber compositions 1 - 3 for roll applications.
Each of compositions 1 - 3 was press molded for 10 minutes at 170C/25 kgf/cm2 to give 5 sheet moldings (thickness = 2 mm). In addition, each of compositions 1 - 3 was wrapped onto a stainless steel roll core (diameter = 5 mm), and the respective silicone rubber-covered rolls (diameter = 15 mm) were prepared by vulcanization and bonding for 10 minutes at 170C.
In each case, the silicone rubber sheets and silicone rubb~r-covered roll were also held for 4 hours in a hot air-circulation oven maintained at 200C.
Each silicone rubber-covered roll with diameter = 15 mm was ground to a diameter of 14 mm using a cylindrical grinder. The roughness was measured on the surface of the resulting silicone rubber-covered roll, and these measurement results are reported in Table 2. The volume resistivity was measured on the sheets in order to evaluate the variation in this value, and these measurement results are also reported in Table 2 below.
Comparison Examples 2 and 3. In Comparison Example 2 (composition 4), silicone rubber sheets and a silicone rubber-covered roll were prepared as in Example 1, but in this case using 10 parts of the silicone rubber powder used in Example 1. In Comparison Example 3 (composition 5), silicone rubber sheets and a silicone rubber-covered roll were prepared as in Example 1, but in this case omitting the silicone rubber powder used in Example 1. The properties of the obtained silicone rubber sheets and silicone rubber-covered rolls were measured as in Example 1, and these results are reported in Tables 1 and 2.
Table 1 Present invention Comparison examples compo- compo- compo- compo- compo-components sition sition sition si4tion sition __ _ silicon 140 140 140 140 140 rubber base (parts) _ _ _ silicon 20 50 150 10 0 ruhber po~der (parts)L_____ _____ _ __ 2~ 3~7 Table 2 ____ _._ Present ~nvention Comparison examples ~easurement compo- compo- compo- compo- compo-valuPs sition sition 6i3tion sition sition ____ __ __ ___ _ .. __ range of variation 7 7 7 7 7 in the volumeI x 10 I x 10 I x 10 1 x 10 I x 10 resistivity values to 7 to 7 to 7 to 7 to 7 ~ohm-cm) 3 x 10 2 x 10 2 x 10 3 x 10 2 x 10 roughness of the roll surface 5 3 3 10 13 R~ ~m~crometers) _ __ ____ ____ ~_~
hardness ~JIS ~) 38 37 36 38 38 tack durlng ~_ +. ____ x xx 2-roll kneading _ ____ ++ : no tack observed, roll workability is very good + : minor degree of tack, roll workability is good x : tack present, roll workability is poor xx : substantial tack observed, roll workability is very poor
Claims (9)
1. An electrically conductive silicone rubber composition for roll applications comprising:
(A) 100 weight parts organopolysiloxane that contains in each molecule at least 2 siloxane units with the following general formula , where R1 represents monovalent hydrocarbon groups lacking aliphatically unsaturated bonds, R2 represents alkenyl, a is a number with a value of zero to 2, b is a number with a value of 1 to 2, and a + b = 1.95 to
(A) 100 weight parts organopolysiloxane that contains in each molecule at least 2 siloxane units with the following general formula , where R1 represents monovalent hydrocarbon groups lacking aliphatically unsaturated bonds, R2 represents alkenyl, a is a number with a value of zero to 2, b is a number with a value of 1 to 2, and a + b = 1.95 to
2.10, (B) 5 to 100 weight parts surfactant-treated inorganic filler, (C) 5 to 50 weight parts electrically conductive carbon black, (D) 15 to 200 weight parts spherical silicone rubber powder whose average particle size is 0.5 to 30 micrometers, and (E) curing agent in a quantity sufficient to cure the present composition.
2. An electrically conductive silicone rubber composition for roll applications according to Claim 1, where the surfactant-treated inorganic filler of component (B) comprises silica micropowder that has been treated with cationic surfactant.
2. An electrically conductive silicone rubber composition for roll applications according to Claim 1, where the surfactant-treated inorganic filler of component (B) comprises silica micropowder that has been treated with cationic surfactant.
3. An electrically conductive silicone rubber composition for roll applications according to Claim 1, where the electrically conductive carbon black of component (C) has an oil absorption within a range of about 50 to 150 mg/100g.
4. An electrically conductive silicone rubber composition for roll applications according to Claim 1, where the spherical silicone rubber powder of component (D) is added at 20 to 150 weight parts per 100 weight parts of the component (A).
5. An electrically conductive silicone rubber composition for roll application according to Claim 1, where the curing agent of component (E) is an organoperoxide.
6. An electrically conductive silicone rubber composition for roll application according to Claim 5, where the organoperoxide is present at 0.1 to 10 weight parts per 100 parts of the component (A).
7. An electrically conductive silicone rubber composition for roll application according to Claim 1, where the curing agent of component (E) is a combination of an organohydrogenpolysiloxane and a platinum group metal compound catalyst.
8. An electrically conductive silicone rubber composition for roll application according to Claim 7, where the organohydrogenpolysiloxane is present at 0.5 to 20 weight parts per 100 weight parts of the component (A) and the platinum group metal compound catalyst is present at 0.1 to 100 weight parts per 1,000,000 weight parts of the component (A).
9. An electrically conductive silicone rubber composition for roll application according to Claim 8, where the platinum group metal compound catalyst is isopropanolic chloroplatinic acid.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4079049A JP2894526B2 (en) | 1992-02-28 | 1992-02-28 | Conductive silicone rubber composition for rolls |
| JP4-079049(1992) | 1992-02-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2090597A1 true CA2090597A1 (en) | 1993-08-29 |
Family
ID=13679049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2090597 Abandoned CA2090597A1 (en) | 1992-02-28 | 1993-02-26 | Electrically conductive silicone rubber composition for application to rolls |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0558045A1 (en) |
| JP (1) | JP2894526B2 (en) |
| CA (1) | CA2090597A1 (en) |
| MX (1) | MX9301036A (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0641437A (en) * | 1992-07-21 | 1994-02-15 | Shin Etsu Polymer Co Ltd | Silicone rubber composition |
| JP2646953B2 (en) * | 1993-01-25 | 1997-08-27 | 信越化学工業株式会社 | Semiconductive roll |
| WO1994018277A1 (en) * | 1993-02-12 | 1994-08-18 | Cabot Corporation | Surfactant modified silica |
| JP3739533B2 (en) * | 1996-09-30 | 2006-01-25 | 東レ・ダウコーニング株式会社 | Continuous production method of liquid silicone rubber base |
| JP3739544B2 (en) * | 1997-09-11 | 2006-01-25 | 東レ・ダウコーニング株式会社 | Continuous production method of silicone rubber composition |
| JPH11116693A (en) * | 1997-10-17 | 1999-04-27 | Dow Corning Toray Silicone Co Ltd | Continuous production of silicone rubber base |
| IT1305129B1 (en) * | 1998-10-21 | 2001-04-10 | S I V E S P A | SHEET FEEDER FOR OFFICE MACHINES AND PROCESS FOR LASUA MANUFACTURE. |
| US6444323B1 (en) * | 1999-09-21 | 2002-09-03 | Tigers Polymer Corporation | Semi-conductive silicone rubber composition |
| JP3999994B2 (en) * | 2002-04-03 | 2007-10-31 | 東レ・ダウコーニング株式会社 | Conductive silicone rubber composition |
| JP4636233B2 (en) * | 2004-08-11 | 2011-02-23 | 信越化学工業株式会社 | Conductive silicone rubber composition and method for producing the same |
| JP4893756B2 (en) * | 2009-01-16 | 2012-03-07 | 信越化学工業株式会社 | Developing roll |
| WO2017116656A1 (en) * | 2015-12-29 | 2017-07-06 | 3M Innovative Properties Company | Composites for high frequency electromagnetic interference (emi) applications |
| FR3103820B1 (en) * | 2019-11-29 | 2022-08-05 | Michelin & Cie | Expandable membrane for baking mold coated with a silicone rubber composition |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1602372A (en) * | 1977-05-18 | 1981-11-11 | Hotfoil Ltd | Electrically conductive rubber composition |
| JPS63251464A (en) * | 1987-04-08 | 1988-10-18 | Toray Silicone Co Ltd | Electrically conductive silicone rubber particle |
| JPH02102263A (en) * | 1988-10-11 | 1990-04-13 | Shin Etsu Chem Co Ltd | Conductive silicone rubber composition and cured product |
| JPH07119365B2 (en) * | 1989-03-29 | 1995-12-20 | 東レ・ダウコーニング・シリコーン株式会社 | Silicone rubber composition |
| JP2787707B2 (en) * | 1989-05-29 | 1998-08-20 | 東レ・ダウコーニング・シリコーン株式会社 | Method for producing conductive silicone rubber granules |
| JPH0791464B2 (en) * | 1989-10-31 | 1995-10-04 | 信越化学工業株式会社 | Conductive silicone rubber composition and cured product thereof |
-
1992
- 1992-02-28 JP JP4079049A patent/JP2894526B2/en not_active Expired - Fee Related
-
1993
- 1993-02-25 MX MX9301036A patent/MX9301036A/en unknown
- 1993-02-26 CA CA 2090597 patent/CA2090597A1/en not_active Abandoned
- 1993-02-26 EP EP93103074A patent/EP0558045A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05239361A (en) | 1993-09-17 |
| JP2894526B2 (en) | 1999-05-24 |
| MX9301036A (en) | 1993-11-01 |
| EP0558045A1 (en) | 1993-09-01 |
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