JP2001329093A - Foaming composition and electrophotographic member using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foaming composition having low hardness and low permanent compression strain properties. SOLUTION: The foaming composition comprises (A) a rubber having a constituting unit (α) which is derived from at least one of butadiene and isoprene and has an alkenyl group in the side chain, (B) a hydrosilyl crosslinking agent, (C) a hydrosilylation catalyst, and (D) a blowing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roll, a charging roll, a transfer roll, a paper feed roll, a toner supply roll,
The present invention relates to a foaming composition used for a layer forming roll and the like, and an electrophotographic member using the same.

[0002]

2. Description of the Related Art As a roll such as a developing roll, a charging roll, and a transfer roll used in an electrophotographic apparatus such as a copying machine, a printer, and a facsimile, for example, a roll in which a foam layer is formed on the outer periphery of a shaft is used. ing. Examples of the material for forming the foamed layer include a polyurethane foam material obtained by adding a catalyst or the like to a urethane prepolymer, acrylonitrile-butadiene rubber (NBR), ethylene-
BACKGROUND ART Rubber materials obtained by adding a vulcanizing agent, a foaming agent and the like to general-purpose rubber such as propylene-diene copolymer rubber (EPDM) are used.

[0003]

However, when the above-mentioned polyurethane foam material is used, the cohesive energy of the hard segment is large, which hinders recovery from a deformed state, and is inferior in compression set characteristics. The use of isocyanates creates environmental pollution problems. Further, when the above rubber material is used, general-purpose rubber such as NBR has a high viscosity and is hardly foamed, and the hardness is too high. In addition, although the foamability can be improved by adding a plasticizer, there is a disadvantage that the compression set characteristic is inferior.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a foaming composition having low hardness and excellent compression set characteristics and an electrophotographic member using the same.

[0005]

Means for Solving the Problems In order to achieve the above object, the present invention provides, as a first gist, a foamed composition containing the following components (A) to (C) and the component (D). (A) a structural unit (α) derived from at least one of butadiene and isoprene and having an alkenyl group in a side chain
With rubber. (B) a hydrosilyl crosslinking agent. (C) a hydrosilylation catalyst. (D) a foaming agent.

[0006] A second aspect of the present invention provides an electrophotographic member using the above foam composition.

The present inventors have intensively studied a foaming composition capable of obtaining an electrophotographic member having low hardness and excellent compression set characteristics. As a result, when the foaming agent (D component) is used together with the specific rubber (A component), the hydrosilyl cross-linking agent (B component), and the hydrosilylation catalyst (C component), the low hardness is obtained as in the case of using the silicone rubber. The present inventors have found that excellent compression set characteristics can be obtained in the present invention, and have reached the present invention. This is because the specific rubber (component (A)) does not have crystallinity and is excellent in flexibility, and since the crosslinking is a siloxane bond, it does not re-crosslink when deformed and has excellent recoverability. It is inferred.

When the hydrosilyl cross-linking agent (component B) is represented by the above-mentioned specific formula, the compatibility with the above-mentioned specific rubber (component A) becomes good, and the compression set characteristic is improved. Is further improved.

In the case where the specific rubber (component A) has the structural unit (α) and the structural unit (β) derived from styrene, the dispersion of fillers and additives Properties, compression set characteristics, strength, electrical characteristics, etc. are further improved.

[0010]

Next, an embodiment of the present invention will be described.

The foaming composition of the present invention contains a foaming agent (component D) together with a specific rubber (component A), a hydrosilyl crosslinking agent (component B), and a hydrosilylation catalyst (component C).

The specific rubber (component (A)) is not particularly limited as long as it is derived from at least one of butadiene and isoprene and has a structural unit (α) having an alkenyl group in a side chain. Alternatively, a millable rubber may be used. The above specific structural unit (α)
Is not particularly limited, and examples thereof include structural units represented by the following structural formulas (I) to (III). Then, the alkenyl group (vinyl group, isopropenyl group), which is a side chain in the structural unit, is subjected to a crosslinking reaction to form a three-dimensional network structure, and exhibits rubber-like elasticity.

[0013]

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The rubber having the specific structural unit (α) (component A) specifically includes isoprene rubber (IR), butadiene rubber (BR), and IR-BR copolymer rubber. It may be a liquid rubber or a millable type rubber. Among them, liquid rubber is preferably used in that it has low hardness and excellent compression set characteristics. These may be used alone or in combination of two or more.

The specific rubber (component (A)) may have a structural unit (β) derived from styrene together with the specific structural unit (α). The styrene may have a substituent, and the substituent is preferably an alkyl group, particularly preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a sec-butyl group. And a C1-C5 alkyl group such as a tert-butyl group.

The above structural unit (α) and structural unit (β)
Among the rubbers (component (A)) having the following general formula (I),
The isoprene-styrene copolymer rubber represented by V) is preferably used.

[0017]

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In the specific rubber (component A), the content ratio of the structural unit (α) is 0.5% of the whole rubber (component A).
It is preferably set in the range of 80 to 80% by weight, particularly preferably 1.5 to 20% by weight. That is, if the content ratio of the structural unit (α) is less than 0.5% by weight, the crosslinking reaction becomes insufficient, and the stability of the foam may be deteriorated. This is because the network structure due to the crosslinking becomes too dense, and the foam may become hard or brittle.

When the specific rubber (component A) has the structural unit (α) and the structural unit (β), the content of the structural unit (β) is 5 to 30% of the whole rubber (component A). It is preferably set in the range of 10% by weight, particularly preferably 10 to 25% by weight. That is, if the content of the structural unit (β) is less than 5% by weight, the effect of styrene may not be sufficiently obtained. Conversely, if the content exceeds 30% by weight, the rubber becomes highly viscous and the moldability becomes poor. This is because there is a possibility that the compression set property may be deteriorated.

The specific rubber (component (A)) can be produced, for example, as follows. That is, first, at least one of butadiene and isoprene and, if necessary, styrene are prepared as monomer components. Then, the monomer component can be obtained by homopolymerization or copolymerization by various methods such as anionic polymerization in the presence of an appropriate catalyst (for example, a lithium catalyst or a Ziegler catalyst).

The number average molecular weight (Mn) of the specific rubber (component (A)) is preferably set in the range of 7 to 2.5 million, particularly preferably 2,000 to 100,000.
000. Number average molecular weight (M) of the rubber (A component)
By setting n) within the above range, the handleability is excellent and the crosslinking reaction can be performed satisfactorily. Above all,
When the rubber (A component) has only the structural unit (α), the number average molecular weight (Mn) is 700 to 60,000.
The range of 0 is preferable, and especially preferable is 2,000-5.
It is 0000. When the rubber (A component) has a structural unit (α) and a structural unit (β), the number average molecular weight (Mn) is preferably in the range of 1,000 to 100,000, particularly preferably 10 to 100,000. 000-80,
000.

The viscosity of the rubber (component (A)) is 100 to 3
The range of 100,000 (mPa · s / 25 ° C) is preferable, and particularly preferably 1,000 to 500,000 (mPa · s / 25 ° C).
It is.

The hydrosilyl crosslinking agent (component B) used with the above specific rubber (component A) is not particularly limited, and includes those having a hydrosilyl group in the molecule. The above-mentioned hydrosilyl group means a group in which a hydrogen atom is bonded to at least one of the four bonds of a silicon atom.

Among the above hydrosilyl crosslinking agents (component B), the following general formulas (1) to (3) are preferred in that compatibility with the rubber (component A) is improved and compression set characteristics are further improved. The hydrosilyl compound represented by the formula (1) is preferably used. Each of the repeating units m, n, p, and q may be in any polymerization form such as random polymerization and block polymerization.

[0025]

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[0026]

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[0027]

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The hydrosilyl compounds represented by the above general formulas (1) to (3) can be produced, for example, by the following methods (1) to (4), and can be carried out relatively easily. Is particularly preferred.

In the molecular structure, a chlorosilyl group (SiC
l) is converted to a reducing agent (LiAlH
₄ , NaBH ₄ ) to reduce the chlorosilyl group to a hydrosilyl group.

A hydrocarbon compound having a functional group,
A method of producing by reacting a compound having both a functional group capable of reacting with the above functional group and a hydrosilyl group.

[0031] A method of producing a hydrocarbon-based compound having an alkenyl group and a polyhydrosilane compound by reacting the resulting reactant such that a hydrosilyl group remains in the molecular structure of the obtained reactant.

A method for producing a compound by reacting a cyclic siloxane having a hydrosilyl group with a cyclic siloxane having a hydrocarbon group.

Of the hydrosilyl compounds thus obtained, those represented by the following structural formulas (4) to (8) are particularly preferred. In addition, each repeating unit may be in any polymerization form such as random polymerization and block polymerization.

[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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The hydrosilyl compound represented by the structural formula (4) can be produced, for example, by the following reaction. The above structural formulas (5) to (8)
The hydrosilyl compound represented by can also be produced by the same method.

[0040]

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The mixing ratio of the above hydrosilyl crosslinking agent (component B) is 100 parts by weight of the rubber (component A) (hereinafter referred to as "parts").
) Is preferably set in the range of 1 to 15 parts, particularly preferably 2 to 8 parts. That is,
When the amount is less than 1 part, the crosslinking is not sufficiently performed, so that the strength and the compression set tend to be deteriorated. On the other hand, when the amount is more than 15 parts, the crosslinking is excessively advanced, and it may be hard and brittle. It is.

The hydrosilylation catalyst (component C) used together with the above specific rubber (component A) and hydrosilyl cross-linking agent (component B) is not particularly limited as long as it can exhibit a catalytic function for a crosslinking reaction. For example, solids such as chloroplatinic acid, complexes of chloroplatinic acid with alcohols, aldehydes, ketones, etc., platinum / vinylsiloxane complexes, platinum / olefin complexes, platinum / phosphite complexes, platinum, alumina, silica, carbon black, etc. Those supporting platinum are exemplified. Examples of the catalyst other than the platinum compound include a palladium compound, a rhodium compound, an iridium compound, and a ruthenium compound. These may be used alone or in combination of two or more.

The foaming agent (component D) used together with the components A to C is not particularly limited. For example, azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), azobisisobutyro Such as nitrile (AIBN), p, p'-oxybis (benzenesulfonylhydrazide) (OBSH), p-toluenesulfonylhydrazide (TSH), p-toluenesulfonylacetone hydrazone (TSH derivative), and hydrazodicarbonamide (HDCA). Organic foaming agents,
Inorganic foaming agents such as sodium hydrogen carbonate (NaHCO ₃ ); These may be used alone or in combination of two or more. Among these, it does not inhibit crosslinking, and the crosslinking rate and foaming balance are suitable for high foaming.
ADCA, DPT and NaHCO ₃ are preferably used.

The compounding ratio of the foaming agent (component D) is preferably set in the range of 0.3 to 8 parts, more preferably 1 to 3, with respect to 100 parts of the specific rubber (component A).
Department. That is, if the blending ratio of the foaming agent (D component) is less than 0.3 part, foaming is difficult, and a stable cell structure cannot be obtained. Conversely, if it exceeds 8 parts, crosslinking inhibition is caused and compression set is caused. Is larger.

The foam composition of the present invention contains
In addition to the D component, conductive agents, fillers such as silica, quartz, calcium carbonate, talc, and mica, plasticizers, crosslinking accelerators,
You may mix | blend a crosslinking retarder, an antioxidant, etc. suitably. As the conductive agent, acetylene black containing few impurities is preferably used.

The foam composition of the present invention can be prepared, for example, as follows. That is, first, the liquid rubber as the specific rubber (A), the hydrosilylation catalyst (C component), and the foaming agent (D component) are blended at an appropriate ratio to prepare a liquid main agent, and a hydrosilyl crosslinking agent is prepared. A liquid crosslinking agent containing (B component) is prepared. In addition, if necessary, components other than the above-mentioned components A to D are added to the liquid main agent and the liquid crosslinking agent, respectively. And
In use, it can be prepared by mixing a liquid base and a liquid crosslinking agent. As described above, when a liquid rubber is used as the specific rubber (A), from the viewpoint of storage stability, the liquid main agent and the liquid crosslinking agent are separately stored, and the two liquids are mixed when used. Is preferred. In addition,
As the rubber (A component), a millable rubber can be used instead of the liquid rubber.

The foam composition of the present invention can be used, for example, in a copying machine,
In electrophotographic devices such as printers and facsimile machines,
It can be used for electrophotographic members such as a developing roll, a charging roll, a transfer roll, a paper feed roll, a toner supply roll, a toner layer forming member, a cleaning blade, and a charging blade.

As an example of an electrophotographic member using the foaming composition of the present invention, as shown in FIG. 1, a developing roll in which a foam layer 2 made of a foaming composition is formed on the outer peripheral surface of a shaft 1 is shown. can give.

The shaft 1 is not particularly limited.
For example, a metal core made of a solid metal body, a metal cylindrical body whose inside is hollowed out, and the like are used. Examples of the material include stainless steel, aluminum, and iron plated. If necessary,
An adhesive, a primer, or the like may be applied on the shaft 1, and the adhesive, the primer, or the like may be made conductive as necessary.

The foam layer 2 formed on the outer peripheral surface of the shaft 1
Is formed using the foam composition of the present invention, and the cell (bubble) diameter in the foam layer 2 is preferably 500 μm or less, particularly preferably 200 μm or less.

The thickness of the foam layer 2 is 0.5 to 10 mm
Is preferably set in the range of, particularly preferably 3 to 6
mm.

The developing roll can be manufactured, for example, as follows. That is, first,
A foam composition (a liquid base material and a liquid crosslinking agent) to be a material for forming the foam layer 2 is prepared by the same method as described above. Then, a liquid base material and a liquid crosslinking agent as the foamed layer 2 forming material (foamed composition) are filled in an injection molding die in which a core metal serving as the shaft body 1 is set, and heated under predetermined conditions. Perform vulcanization foaming. Thereafter, by removing the mold, a developing roll having the foam layer 2 formed along the outer peripheral surface of the shaft body 1 can be manufactured.

The vulcanization and foaming conditions are as follows:
100-180 ° C x
0.5 to 30 minutes is preferred.

The method of forming the foam layer 2 is not limited to the injection molding method, but may be formed by a casting method or the like.

Further, the developing roll is not limited to the two-layer structure as shown in FIG. 1, and an intermediate layer or a surface layer may be formed on the outer peripheral surface of the foam layer 2.

Next, examples will be described together with comparative examples.

[0057]

Example 1 IR-BR copolymer rubber (Kuraray Co., Ltd., Kuraprene LIR-390) [IR: BR = 10: 90 (weight ratio), Mn: 34,000, content ratio of structural unit (α): 9 0.3 parts by weight], 100 parts of a hydrosilyl crosslinking agent represented by the formula (6), 30 ppm of a hydrosilylation catalyst (chloroplatinic acid), and 2 parts of a blowing agent (ADCA).
0.05 parts of acetylene alcohol (3,5-dimethyl-1-hexyn-3-ol: DMHO) and 10 parts of Denka Black were prepared. The IR-BR copolymer rubber, a hydrosilylation catalyst (chloroplatinic acid), a foaming agent (ADCA), and denka black are mixed to prepare a liquid base material, and a hydrosilyl crosslinking agent, acetylene alcohol and Were mixed to prepare a liquid crosslinking agent. Next, a core metal as a shaft (diameter 10 mm, made of SUS304)
The liquid main agent and the liquid crosslinking agent were mixed and filled into an injection molding die in which was set, and heated at 150 ° C. for 15 minutes to perform vulcanization and foaming. Thereafter, the roll was removed from the mold to form a roll having a foamed layer (thickness: 3 mm) formed along the outer peripheral surface of the shaft.

[0058]

Example 2 A roll was produced in the same manner as in Example 1 except that the type of the foaming agent was changed to NaHCO ₃ .

[0059]

Example 3 The type of the hydrosilyl crosslinking agent was determined by the formula (5)
And the type of blowing agent to D
A roll was produced in the same manner as in Example 1 except that the roll was changed to PT.

[0060]

Example 4 Millable type butadiene rubber (JSR
BR02LL) [Mn: 700,000, structural unit (α)
Content: 2% by weight], 100 parts of the hydrosilyl crosslinking agent represented by the formula (6), 30 ppm of a hydrosilylation catalyst (chloroplatinic acid), 2 parts of a blowing agent (ADCA), and Denka Black. 10 parts, and kneaded with a roll to prepare a rubber composition. Next, the above rubber composition was filled into an injection molding die in which a core (diameter: 10 mm, made of SUS304) as a shaft was set.
The mixture was heated at 50 ° C. for 15 minutes to perform vulcanization and foaming. Thereafter, the mold is removed, and a foam layer (thickness 3) is formed along the outer peripheral surface of the shaft body.
mm) was formed.

[0061]

Example 5 Butadiene rubber (BR02L manufactured by JSR Corporation)
Instead of L), a millable type isoprene rubber (Clayton IR310 manufactured by Shell Japan) [Mn: 25
0,000, the content ratio of the structural unit (α): 1% by weight]. Otherwise, in the same manner as in Example 4, a roll was produced.

[0062]

Comparative Example 1 The material for forming the foamed layer was changed to
A roll was produced in the same manner as in Example 1 except that the polyurethane foam material described in JP-A-57-57 was changed. That is, first, propylene oxide and ethylene oxide are added to glycerin, and finally 100 g of a polyether-based polyol having a molecular weight of 5000 and a polyoxyethylene chain content of 20% by weight, and tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., TDI80, 2, 6
(Amount of isomer: 20%) 25 g was reacted to prepare a urethane prepolymer having an NCO content of 7.5% by weight. Then, 25 g of a conductive carbon aqueous dispersion (W-311W, manufactured by Lion Corporation) containing 8 wt% of conductive carbon black in 100 g of the urethane prepolymer, 1 g of N-methylmorpholine and 0.1 g of triethylamine as a reaction activating catalyst. 3 g and 1.5 g of a silicone-based surfactant (L-520, manufactured by Nippon Unicar Co., Ltd.) were added thereto, followed by stirring and mixing for 8 seconds to form a foam layer made of polyurethane foam.

[0063]

Comparative Example 2 The material for forming the foamed layer was changed to
A roll was prepared in the same manner as in Example 1 except that the rubber composition was changed to the rubber composition described in JP-A-834. That is, NB
R (Nippon DN401LL, manufactured by Zeon Corporation) and 70 parts of EPDM (EPT402, manufactured by Mitsui Petrochemical Industries, Ltd.)
1) 30 parts, 32 parts of carbon black (Diablack H, manufactured by Mitsubishi Chemical Corporation), 5 parts of zinc oxide, 1 part of stearic acid, 3.5 parts of sulfur, and a vulcanization accelerator (Sanshin Chemical Industries, Ltd.) 1 part of Suncellar CM) and a foaming agent [Vinihole A
C # 3 and 15 parts of a 1: 1 mixture of cell paste (all manufactured by Eiwa Chemical Co., Ltd.) and kneaded for 15 minutes to prepare a rubber composition. Then, a roll was produced in the same manner as in Example 1 except that a foamed layer was formed using this rubber composition.

Using the rolls of the product of the example and the product of the comparative example thus obtained, each characteristic was evaluated according to the following criteria. The results are shown in Table 1 below.

[Cell Diameter] A cross-sectional photograph of the foamed layer was taken using an optical microscope, and the average cell diameter was determined.

[Hardness] The hardness of the foamed layer was measured using an Asker C hardness meter (manufactured by Kobunshi Keiki Co., Ltd.).

[Compression Set] The compression set of the foamed layer was measured according to JIS K 6301 under the conditions of a temperature of 70 ° C., a test time of 22 hours and a compression ratio of 25%.

[Electrical Resistance] The electrical resistance (median value) of the foamed layer was measured using a 1 mm ² electrode in accordance with JIS K 6911.

[Material preservability] After leaving the foamed layer forming material at room temperature (25 ° C.) for 3 months, take out the supernatant and the lower bottom 10% each for the liquid one, and take the upper part for the solid one. A portion up to 5 mm from the surface and the inside were taken out, and the mixture was formed into a sheet. The electric resistance of this sheet was measured, and the liquid stability was evaluated based on the electric resistance difference. Then, those having an electrical resistance difference of one digit or less were evaluated as ○, and those exceeding one digit were evaluated as x.

[Detachment (Pressing Test)] After the above-mentioned roll was arranged in parallel with a metal cylinder having a diameter of 30 mm,
Press the roll with 0.5mm concave in the radial direction and press
Left for a week. Then, the roll was taken out, assembled into a printer, and a solid black image was displayed. And
If the image corresponding to the pressed part is not white,
Those in which the image corresponding to the pressed portion was white were evaluated as x.

[Development Characteristics] The above-mentioned roll was incorporated into a printer, and left for 1 week in an environment of 35 ° C. × 85%.
The character image was printed, and the image was visually evaluated. Then, those in which there was no break in the thin line and no blurring of the image was observed were evaluated as ○, and those in which there was a break in the thin line and blurring of the image was observed were evaluated as x.

[Charging Characteristics] A halftone image was visually evaluated according to the above-mentioned developing characteristics. The image was evaluated as x when the image had streaks having a high density due to the dent of the charging roll, and evaluated as ○ when the image had no streaks.

[Transfer Characteristics] Evaluation was performed according to the above-described development characteristics.

[Feeding Characteristics] 100 sheets of copy paper (A4 size) were placed, the paper was pulled by a feeding roll, and the force was measured using a torque gauge. And the torque is 40
Those within the range of 0 ± 50 gf were evaluated as ○, and those out of this range were evaluated as ×.

[Bloom on the surface] The environment at -10 ° C and 40 ° C was cycled 10 times for 2 hours each,
After standing still for more than a day, the surface was observed with an optical microscope (50 times magnification). Then, those in which no change in the surface was observed were evaluated as も の, and those in which bloom was observed were evaluated as ×.

[Change in Wet Heat] After measuring the outer diameter of the roll in an environment of 23 ° C. × 53%, the roll was allowed to stand in an environment of 45 ° C. × 95% for 168 hours, and the expansion rate of the outer diameter of the roll was measured.
Then, those having an expansion rate of 0.3% or less were evaluated as ○, and those exceeding 0.3% were evaluated as ×.

[0077]

[Table 1]

[0078]

[Table 2]

From the above results, it can be seen that all the products of Examples have low hardness, excellent compression set characteristics, and other characteristics.

On the other hand, since the product of Comparative Example 1 uses a polyurethane foam material, it has inferior compression set characteristics and large set, and is inferior in developing characteristics, charging characteristics, transfer characteristics and paper feeding characteristics. It can be seen that the material is inferior in storability because of its reactivity even at normal temperature, and the change in wet heat is large due to urethane bonding. In addition, it can be seen that the product of Comparative Example 2 has high hardness, is inferior in compression set characteristics, is large in set, is inferior in development characteristics, charging characteristics, transfer characteristics, and paper feeding characteristics, and generates bloom on the surface.

[0081]

As described above, the foamed composition of the present invention comprises:
The above specific rubber (A component) and a hydrosilyl crosslinking agent (B
Component) and a foaming agent (D component) together with the hydrosilylation catalyst (C component), so that electrophotographic members such as rolls obtained using the same have low hardness and excellent compression set. Has characteristics.

When the hydrosilyl crosslinking agent (component B) is represented by the above-mentioned specific formula, the compatibility with the rubber (component A) becomes good, and the compression set characteristic is further improved. improves.

When the rubber (component (A)) has the structural unit (α) and the structural unit (β) derived from styrene, the dispersibility of the filler and the additive is reduced. The compression set property, strength, electrical properties and the like are further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a developing roll using the foam composition of the present invention.

[Explanation of symbols]

 1 shaft 2 foam layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16C 13/00 F16C 13/00 E G03G 15/02 101 G03G 15/02 101 15/08 501 15 / 08501A 501D 504 504D 15/16 103 15/16 103 (72) Inventor Kunio Ito 3-1, Higashi 3-chome, Komaki City, Aichi Prefecture Inside (72) Inventor Akihiko Kachi 1-3-1, Higashi 3-chome, Komaki City, Aichi Prefecture Tokai Rubber (72) Inventor: Kenichi Ohoe, 3-3-1 Higashi Higashi, Komaki City, Aichi Prefecture Tokai Rubber Industry Co., Ltd.

Claims (4)

[Claims] 1. A foaming composition characterized by containing a component (D) together with the following components (A) to (C). (A) a structural unit (α) derived from at least one of butadiene and isoprene and having an alkenyl group in a side chain
With rubber. (B) a hydrosilyl crosslinking agent. (C) a hydrosilylation catalyst. (D) a foaming agent. 2. The hydrosilyl crosslinking agent as the component (B) is represented by at least one general formula selected from the group consisting of the following general formulas (1), (2) and (3). The foamed composition according to claim 1, which is to be prepared. Embedded image Embedded image Embedded image 3. The foam composition according to claim 1, wherein the rubber as the component (A) has a structural unit (α) and a structural unit (β) derived from styrene. 4. An electrophotographic member using the foamed composition according to claim 1.