JP2000007919A - Catalyst-containing primer composition and expandable silicone rubber roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition which improves adhesion of a rubber to a metallic shaft by compounding an alkoxysilane or a partial hydrolysis condensate thereof, a platinum catalyst and a silicone resin. SOLUTION: The objective primer composition comprises 100 pts.wt. of an alkoxysilane represented by the formula such as tetraethoxysilane or the like or its partial hydrolyzate, 0.01-20 pts.wt. of a platinum-based catalyst such as platinum chloride or the like and 0.3-200 pts.wt. of a silicone resin such as a methyl silicone resin or the like. The primer composition is coated on a metallic shaft 1 and is baked to form a catalyst-containing primer layer 2. The shaft and an expandable silicone rubber compound are integrally sheeted from an extruder and subjected to baking thereby effecting expansion vulcanization to form an expandable silicone rubber layer 3. The expandable rubber compound is obtained by mixing an organohydrogenpolysiloxane crosslinking agent, a platinum-based catalyst, an expanding agent and the like with a vinyl group-containing organopolysiloxane. In the formula, R is a hydrocarbon; R' is an alkyl or the like; and (n) is 1-3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roll used for a developing portion of a laser beam printer, a copying machine, or the like.
The present invention relates to a catalyst-containing primer composition which is a raw material for producing a charging roll, a toner conveying roll, a transfer roll, a photosensitive drum cleaning roll, a paper feed roll used for a paper feeding portion, a paper discharge roll, and the like, and a foamable silicone rubber roll using the same. .

[0002]

2. Description of the Related Art Conventionally, a semiconductive rubber material having a volume resistivity of 10 ³ to 10 ⁹ Ωcm is used for a rubber roll used for a developing portion of a laser beam printer, a copying machine, or the like from the viewpoint of a toner conveying force and the like. In addition, a rubber material having high friction is used for the rubber roll used for the paper feeding portion in terms of frictional resistance with paper. In recent years, in order to further reduce the size and weight of printers and copiers, and to improve the performance of image processing, rubber rolls that can obtain a large contact area even at a low roll pressure have been demanded. A foamable silicone rubber roll has been used instead of a rubber-type silicone rubber roll. In the production of this foamable silicone rubber roll, usually, a primer composition is applied to a washed metal shaft and baked at 150 to 400 ° C. for 3 to 30 minutes to form a cured primer layer. After extruding the metal shaft body and the foamable silicone rubber composition integrally with an extruder, the mixture was cured at a high temperature of 150 ° C. or higher,
It is performed by cutting and grinding to arbitrary dimensions.

[0003]

In the market, there is a demand for a foamable silicone rubber roll having a lower hardness, and as a method for meeting the demand, a foaming agent added to a silicone rubber compound in the production of the above rubber roll. It is conceivable to increase the amount of. However, when the amount of the foaming agent is increased, the foamable silicone rubber and the metal shaft do not adhere to each other in the curing step, and it is difficult to form the rubber roll. Therefore, the present invention
An object of the present invention is to provide a low-hardness foamable silicone rubber roll by improving the adhesion between the foamable silicone rubber and the metal shaft.

[0004]

According to the present invention, there is provided a compound represented by the following general formula (A): R _(4-n) Si (OR ') _n (where R is a substituted or unsubstituted hydrocarbon group, and R' is an alkyl group) Group or alkoxylated alkyl group, n is an integer of 1 to 3), 100 parts by weight of a partially hydrolyzed condensate thereof, and (B) a platinum-based catalyst 0.01
To 20 parts by weight, and (C) a catalyst-containing primer composition comprising a silicone resin as a main component, and a cured catalyst-containing primer layer comprising the primer composition provided on the surface of a metal shaft. And a foamable silicone rubber roll having a foamable silicone rubber layer provided around the cured primer layer.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 shows an example of the foamable silicone rubber roll of the present invention, in which (a) is a cross-sectional view and (b) is a longitudinal cross-sectional view. In the figure, 1 is a metal shaft, 2 is a catalyst-containing primer layer comprising the catalyst-containing primer composition of the present invention, and 3 is a foamable silicone rubber layer.

As described above, the catalyst-containing primer composition of the present invention comprises (A) an alkoxysilane or a partially hydrolyzed condensate thereof, (B) a platinum-based catalyst, and (C) a silicone resin as main components. It is. The (A) alkoxysilane or its partially hydrolyzed condensate is an essential component for enhancing the adhesion between the foamable silicone rubber and the metal shaft. Examples of the component (A) include a group containing at least two alkoxy groups in one molecule and bonding to a silicon atom other than the alkoxy group, such as a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, Alkyl groups such as hexyl group, octyl group and decyl group; alkenyl groups such as vinyl group; aryl groups such as phenyl group and tolyl group; aralkyl groups such as β-phenylethyl group and β-phenylpropyl group; and hydrogen atoms thereof. A part of which is a chlorine atom, a fluorine atom,
An organosilane having a monovalent substituted or unsubstituted hydrocarbon group substituted with a nitrile group or the like can be given. Specifically,
Examples of the alkoxylan include tetraethoxysilane, tetrapropoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, and vinyltriethoxysilane. Examples of the aminoalkylalkoxysilane include γ-aminopropyltrimethoxysilane and N-β- (aminoethyl) -γ
-Aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl)-
γ-aminopropyltriethoxysilane and the like. In addition, regardless of the type of the alkoxysilane or its partial hydrolyzate, the effect of enhancing the adhesiveness is recognized.

[0007] The platinum-based catalyst which is the component (B) of the catalyst-containing primer composition of the present invention acts as a curing accelerator for addition reaction. As the platinum-based catalyst, for example, chloroplatinic acid, alcohol-modified chloroplatinic acid, platinum black, alumina, silica, those supported on a solid catalyst such as carbon,
Examples include complexes of platinum with olefins, alcohols and vinylsiloxanes, and complexes of chloroplatinic acid with olefins, alcohols and vinylsiloxanes. In the catalyst-containing primer composition of the present invention, the component (B) is used in an amount of 0.01 to 20 as platinum metal with respect to 100 parts by weight of the component (A).
Add parts by weight. When the amount is less than 0.01 part by weight, the effect of the catalyst is not exhibited because the amount of platinum is small, and when the amount exceeds 20 parts by weight, the effective compounding balance with other components is lost, and the catalyst-containing primer cured layer The physical properties are reduced and the adhesive strength is reduced.

[0008] The silicone resin, which is the component (C) of the catalyst-containing primer composition of the present invention, comprises R _a SiO _(4-a)
(R represents an organic group), and examples thereof include a methyl silicone resin, a methyl phenyl silicone resin, and a modified silicone resin obtained by condensing an organic resin and a silicone resin. These resins may be used alone or in combination of two or more. The role of silicone resin is
The present invention is intended to increase the curing speed of the catalyst-containing primer composition and increase the adhesive strength of the catalyst-containing cured primer layer while retaining the components (A) and (B), which are low-molecular-weight volatile substances. According to the study of the present inventors, even when a very small amount of the silicone resin was added, a significant difference was observed between these effects as compared with the case where no silicone resin was added. No harm is recognized even if the amount of addition is increased, but in order to effectively exert the effect of the catalyst-containing primer composition, the component (A) 100
It is preferable to add 0.3 to 200 parts by weight with respect to parts by weight. When the amount is less than 0.3 parts by weight, the cured catalyst-containing primer layer becomes too thin and the adhesive strength is reduced. When the amount exceeds 200 parts by weight, the cured catalyst-containing primer layer becomes too thick and the foamable silicone rubber layer is removed. Although it adheres,
The physical properties of the catalyst-containing primer cured layer itself are reduced, and the adhesive strength is slightly reduced.

The catalyst-containing primer composition of the present invention can be obtained by blending each of the above-mentioned components (A) to (C), but is preferably further diluted with a solvent. It is preferable that the solvent be easily volatilized, and methanol, ethanol,
Alcohol solvents such as isopropanol, aromatic hydrocarbon solvents such as benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, diethylbenzene, trichloroethylene, perchloroethylene, 1,
Chlorinated hydrocarbon solvents such as 1,1-trichloroethane, carbon tetrachloride, and chlorofomur; aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, methylcyclohexane, and dimethylcyclohexane; ketone solvents such as acetone and methyl ethyl ketone; acetic acid Ester solvents such as ethyl are exemplified. Particularly, toluene, benzene, and isopropyl alcohol are preferable. Even if these are used alone,
More than one kind may be used in combination. The amount of the solvent to be added may be appropriately adjusted to an appropriate concentration according to the method of applying the catalyst-containing primer composition. Even if the amount of the solvent is large, the effect of the present invention is not affected as long as the solvent is sufficiently evaporated by drying after coating the primer composition. The catalyst-containing primer composition of the present invention is particularly suitable for bonding foamable silicone rubber to a metal shaft,
It is also applicable to the bonding of foamable urethane rubber and foamable polysulfide rubber.

[0010] The foamable silicone rubber roll of the present invention comprises:
As illustrated in FIG. 1, a catalyst-containing primer cured layer 2 made of the above-mentioned catalyst-containing primer composition provided on the surface of a metal shaft 1, and a foamable material provided around the catalyst-containing primer cured layer 2. It has a silicone rubber layer 3. In order to produce the foamable silicone rubber roll of the present invention, first, the catalyst-containing primer composition is applied to the surface of the metal shaft 1. As a coating method, a general coating machine such as a roll coater or a spray coater may be used, or the primer composition may be soaked in a sponge or the like and applied manually. As the metal shaft 1,
Examples include a conductive metal such as iron, aluminum, copper, zinc, stainless steel, and brass, and a plated conductive metal, which may be appropriately selected in consideration of workability, economy, and the like.

Next, the catalyst-containing primer composition applied to the metal shaft 1 is fired to form a cured catalyst-containing primer layer 2. The firing may be performed using a firing device such as a gear oven or an infrared irradiation furnace. The firing time and temperature may be appropriately determined according to the amount of the catalyst-containing primer composition applied and the size of the metal shaft 1.

Next, the metal shaft 1 on which the catalyst-containing primer cured layer 2 is formed and the foamable silicone rubber compound are integrally separated by an extruder, and then fired in an infrared irradiation furnace or the like to form a foam. A vulcanization reaction is performed to form the foamable silicone rubber layer 3. If necessary, a baking treatment is further performed in a gear oven or the like, and the foaming vulcanization reaction is completely performed, so that the foamable silicone rubber layer 3 is in a stable state.
The sintering time and temperature may be appropriately determined according to the amount of the silicone rubber compound and the size of the metal shaft 1.

The foamable silicone rubber compound mainly comprises a vinyl group-containing organopolysiloxane as a main component, a crosslinking agent (mainly an organohydrogenpolysiloxane),
It contains a platinum-based catalyst, a reaction inhibitor, a vulcanization aid, a physical property aid, a foaming agent, and the like.

As the vinyl group-containing organopolysiloxane, for example, the following general formula:

Embedded image Are exemplified. In this formula, R is a methyl group,
The same or different monovalent hydrocarbon groups selected from an ethyl group, a vinyl group, and a phenyl group;
It is an integer of 0. The vinyl group content in this vinyl group-containing organopolysiloxane is preferably about 0.05 to 3.0 mol%.

As the organohydrogenpolysiloxane as a crosslinking agent, for example, the following general formula:

Embedded image And a compound having at least two hydrogen atoms bonded to a silicon atom in the molecule. In this equation,
R is a hydrogen atom or the same or different monovalent hydrocarbon group selected from a methyl group, an ethyl group and a phenyl group, and n is an integer of 10 to 1,000.

The amount of the above-mentioned organohydrogenpolysiloxane is based on the amount of the vinyl group-containing organopolysiloxane 1
The range is preferably 0.1 to 20 parts by weight with respect to 00 parts by weight. If it is less than 0.1 part by weight, the curing is incomplete,
If the amount exceeds 20 parts by weight, overcuring occurs and the rubber strength decreases. The mixing ratio of the vinyl group-containing organopolysiloxane and the organohydrogenpolysiloxane is such that the hydrogen atom concentration (= H) in the organohydrogenpolysiloxane is based on the vinyl group concentration (= V) contained in the organopolysiloxane. Is H / V = 0.08-
It is preferable to set so as to be in the range of 1.0. If the H / V is less than 0.08, curing is incomplete,
If it exceeds 1.0, overcure occurs and the rubber strength decreases.

As the foaming agent to be added to the foamable silicone rubber compound, any known foaming agent may be used.
Inorganic foaming agents may be used in addition to commonly used organic foaming agents such as 2,2'-azobisisobutyronitrile and azodicarbonamide. The amount of the foaming agent added is 0.1 to 100 parts by weight of the vinyl group-containing organopolysiloxane.
The range is 5 to 4.5 parts by weight. If the amount is less than 0.5 part by weight, foaming does not occur, so that the function as an expandable silicone rubber cannot be obtained. If the amount exceeds 4.5 parts by weight, formation of an expandable silicone rubber roll becomes impossible.

The platinum-based catalyst may be the same as that used in the catalyst-containing primer composition of the present invention.
What is necessary is just to add the catalyst effective amount used. With respect to 100 parts by weight of the vinyl group-containing organopolysiloxane, 0.0
The range of 1 to 0.5 parts by weight is suitable, but may be slightly changed depending on the foaming curing temperature and time.

Other reaction inhibitors include methylvinylcyclotetrasiloxane, acetylene alcohols,
Siloxane-modified acetylene alcohol, hydroperoxide and the like. Organic peroxides are mainly used as vulcanization aids. As a physical property auxiliary agent, non-reinforcing silica is used for the purpose of adjusting hardness and improving heat resistance, or conductive carbon black, nickel, aluminum, metal powder such as copper, zinc oxide, zinc oxide, A conductive filler in which tin oxide is coated on a core material such as metal oxide such as tin oxide, barium sulfate, titanium oxide, and potassium titanate is appropriately used. Further, other additives can be mixed and used as long as the desired properties are not impaired. Examples of such additives include dry silica, wet silica, diatomaceous earth for improving the strength of the foamed conductive sponge roll, and reinforcing fillers obtained by hydrophobically treating these.

Finally, after the foaming vulcanization reaction is completed, the foaming silicone rubber roll cooled at room temperature is ground to a desired size by a grinding machine such as a cylindrical grinder as required. . Thus, the foamable silicone rubber roll of the present invention is obtained.

[0021]

EXAMPLES (Example 1) Primer composition "Primer No. 101A" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) 100
Parts by weight of the primer composition "Primer No. 2
90% by weight of the primer composition "Primer No. 4" (trade name, trade name)
Platinum-based catalyst "CAT-PL-2" (same name, trade name)
One part by weight and 50 parts by weight of toluene were uniformly mixed to prepare a catalyst-containing primer composition. The prepared catalyst-containing primer composition contained 0.01 part by weight of a platinum-based catalyst, 35 parts by weight of a silicone resin, and 450 parts by weight of a solvent, where alkoxysilane was 100 parts by weight. Next, a metal shaft “SUM22” (φ6 × 100 mm, washed with toluene)
The above-mentioned catalyst-containing primer composition was applied to a central portion of 50 mm of SUS22 obtained by electroless nickel plating) using a special sponge. Then, the metal shaft coated with the catalyst-containing primer composition was placed in a gear oven for 150 minutes.
The mixture was baked at 30 ° C. for 30 minutes and cooled at room temperature for 30 minutes or more.

Next, the silicone rubber compound "KE
-151U "(same name, trade name) for 100 parts by weight,
2 parts by weight of an organic peroxide vulcanizing agent “C-3” (the same name, trade name), 3 parts by weight of organohydrogenpolysiloxane,
Appropriate amount of blowing agent azobisisobutyronitrile "KEP-1
3 "(same name, trade name), an expandable silicone rubber compounding compound containing chloroplatinic acid and a reaction control agent as a catalyst was prepared. Then, the metal shaft on which the catalyst-containing primer cured layer is formed and the foamable silicone rubber compound are integrally extruded into an outer diameter of 12 mm using an extruder, and then fired at 300 ° C. for 6 minutes in an infrared irradiation furnace. Thus, a foamable silicone rubber layer was formed, and a foamable silicone rubber roll prototype was molded. Further, it was baked at 200 ° C. for 6 hours in a gear oven and cooled at room temperature for 1 hour or more. The idling torque of the foaming silicone rubber roll prototype thus obtained was measured with a torque gauge, and the results are shown in Table 1.

Example 2 In the catalyst-containing primer composition, except that the blending amount of the platinum-based catalyst was 1 part by weight,
A foamable silicone rubber roll prototype was formed in the same manner as in Example 1. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 A foamable silicone rubber roll prototype was formed in the same manner as in Example 1 except that the amount of the platinum-based catalyst was changed to 20 parts by weight in the catalyst-containing primer composition. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 A silicone rubber compound containing "KE-3502" containing conductive carbon black was used.
U "(Shin-Etsu Chemical Co., Ltd., trade name)
A foamable silicone rubber roll prototype was formed in the same manner as in Example 1. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 5 A foamable silicone rubber roll prototype was formed in the same manner as in Example 1 except that aluminum (A2011BD) was used as the metal shaft.
The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A foamable silicone rubber roll prototype was molded in the same manner as in Example 1 except that the amount of the platinum-based catalyst was changed to 0.005 parts by weight in the catalyst-containing primer composition. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 2 A foamable silicone rubber roll prototype was molded in the same manner as in Example 1 except that the amount of the platinum-based catalyst was changed to 25 parts by weight in the catalyst-containing primer composition. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 3 A foamable silicone rubber roll prototype was formed in the same manner as in Example 1 except that the amount of the alkoxysilane was changed to 0.25 parts by weight in the catalyst-containing primer composition. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 2.

(Comparative Example 4) A foamable silicone rubber roll prototype was molded in the same manner as in Example 1 except that the amount of the alkoxysilane was changed to 150 parts by weight in the catalyst-containing primer composition. The idling torque of the foamable silicone rubber roll prototype thus obtained was measured in the same manner as in Example 1, and the results are shown in Table 2.

[0031]

[Table 1]

[0032]

[Table 2]

[Method of Measuring Idling Torque] As shown in FIG. 2, a portion of the foaming silicone rubber roll mold 4 from the end of the exposed metal shaft to a portion 15 mm from the end was fixed to a torque gauge 5, and a foaming silicone rubber portion was formed. Was gripped with bare hands and the torque gauge was rotated to measure the idling torque. The reference value for judging the quality of the adhesion is 2.4 kgf. c
m.

[0034]

According to the catalyst-containing primer composition of the present invention, the adhesion between the expandable silicone rubber and the metal shaft becomes strong, and the highly foamed silicone rubber can be bonded to the shaft. A rubber roll can be obtained. Therefore, the foamable silicone rubber roll of the present invention has a lower hardness than the conventional one, and is used mainly in a developing portion of a laser beam printer, a copying machine, etc., thereby improving image processing performance and improving printing quality. This can contribute to downsizing, power saving, and cost reduction of the device.

[Brief description of the drawings]

FIG. 1 shows an example of an expandable silicone rubber roll using a catalyst-containing primer composition of the present invention,
a) is a transverse sectional view, and b) is a longitudinal sectional view.

FIG. 2 is an explanatory view showing a test method for measuring an idling torque for confirming adhesion of an expandable silicone rubber roll using the catalyst-containing primer composition of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal shaft 2 ... Catalyst containing primer layer 3 ... Foamable silicone rubber layer 4 ... Foamable silicone rubber roll prototype 5 ... Torque gauge

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03G 15/08 501 G03G 15/08 501D 2H077 15/16 15/16 3F343 15/20 103 15/20 103 4J002 F term (for reference) 2C059 BB11 CC09 CC15 2H003 BB11 BB13 BB16 CC05 2H032 AA05 2H033 BB06 BB08 BB14 2H072 JC01 JC07 JC08 2H077 AD06 FA12 FA16 FA22 3F343 FA02 FB02 FB04 JA01 JA11 JD0017 DE07J037 GJ00 GM00

Claims (2)

[Claims] (A) General formula: R _(4-n) Si (OR ') _n
Wherein R is a substituted or unsubstituted hydrocarbon group, R ′ is an alkyl group or an alkoxylated alkyl group, and n is an integer of 1 to 3, or 100 parts by weight of a partially hydrolyzed condensate thereof. Part, (B) platinum-based catalyst
A catalyst-containing primer composition comprising 0.01 to 20 parts by weight and (C) a silicone resin as a main component. 2. A metal shaft provided on a surface of a metal shaft.
A foamable silicone rubber roll comprising: a catalyst-containing primer cured layer comprising the catalyst-containing primer composition described above; and a foamable silicone rubber layer provided around the catalyst-containing primer cured layer.