JPH0453434B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a fixing roll for copying machines, facsimile machines, printers, etc., which fixes toner powder images of dry electrophotography by heating and/or pressure. [Prior art and problems to be solved by the invention] Conventionally, in dry electrophotography, when a toner powder image transferred from a transfer drum or the like onto a support such as paper is fixed, heating is performed. A method of fixing a toner powder image onto a support such as paper by heating and/or applying pressure using a rubber roll (fixing roll) is commonly used. A silicone rubber layer with excellent properties and a constant thickness is used. In this case, the silicone rubber layer of the fixing roll is a heat-curable silicone rubber crosslinked with an organic peroxide or an addition reaction (Japanese Patent Publication No. 36-1277, JP-A-54-1999).
No. 159485, Japanese Patent Publication No. 61-4855) and room temperature curing silicone rubber (Japanese Patent Publication No. 159485)
No. 2439, Japanese Unexamined Patent Publication No. 55-75446). However, in recent years there has been a trend to require flame retardant properties for copying machine parts, and UL-478 (standard for information processing and office equipment) has V-94 (flammability test for plastic materials for equipment parts).
It is becoming necessary to use materials of one grade or more. On the other hand, the number of models such as high-end color copiers and low-speed, low-cost personal copiers is increasing, and along with this, the types of toners used are also increasing. Furthermore, in order to meet the demand for image clarity, the surface smoothness of the roll is required, and there is a tendency to shift to products with low rubber curing. If you request something with smooth surface or low rubber hardness,
There are problems such as the increased silicone content making it difficult to impart flame retardancy, and until now it has not been possible to supply rolls for copying machines using cured addition-type silicone rubbers that impart flame retardancy. The present invention was made in view of the above circumstances, and an object of the present invention is to provide a fixing roll whose rubber layer is a cured product of an addition-type silicone rubber composition that has the required rubber hardness, moldability, surface smoothness, and flame retardancy. With the goal. [Means and effects for solving the problem] The present inventors have proposed that the fixing rubber layer formed on the outer peripheral surface of a roll body made of a metal shaft or the like is formed from a cured product of an addition-type silicone rubber composition. As a result of extensive studies, we found that organopolysiloxane containing two or more vinyl groups in one molecule is used for reinforcing properties and rubber hardness control, and it is especially preferable to use an organopolysiloxane containing two or more vinyl groups in each molecule, and it is particularly preferable to use an organopolysiloxane containing an aliphatic unsaturated hydrocarbon group only at both ends. and an organopolysiloxane having three or more aliphatic unsaturated hydrocarbon groups in one molecule, and two or more hydrogen atoms bonded to silicon atoms in one molecule, A sufficient amount of organohydrodiene polysiloxane is blended so that the number of hydrogen atoms bonded to silicon atoms is 0.5 to 5 per aliphatic unsaturated hydrocarbon of the organopolysiloxane, and the filler is Fumed silica with a surface area (BET method) of 50 m ² /g or more is used, and a small amount of the fumed silica is used, that is, the organopolysiloxane
Blended at a ratio of 3 to 30 parts by weight per 100 parts by weight,
Furthermore, an addition type silicone rubber composition is constructed using a specific amount of a triazole compound as a flame retardant,
This is cured using platinum or a platinum compound as a catalyst,
When a rubber layer is formed on the outer circumferential surface of the fuser roll body,
We have discovered that the rubber layer has low hardness, has excellent surface smoothness, and high flame retardancy, and also has good moldability when forming the rubber layer on the fixing roll body, The present invention has been accomplished. The present invention will be explained in more detail below. The fixing roll according to the present invention heats and/or fixes toner powder images in equipment using an electrophotographic process such as copying machines, facsimile machines, and printers.
The rubber layer formed on the outer peripheral surface of the roll body consists of: (1) two aliphatic unsaturated hydrocarbon groups bonded to silicon atoms in one molecule; Organopolysiloxane having 100 parts by weight (2) Organohydrodiene polysiloxane having two or more silicon-bonded hydrogen atoms in one molecule (1) Bonded to the silicon atom for one aliphatic unsaturated hydrocarbon of component (3) Fumed silica filler with a specific surface area (BET method) of 50 m ² /g or more 3 to 30 parts by weight (4) Platinum or platinum compound Catalyst amount (5) It is characterized in that it uses a cured product of an addition type silicone rubber composition containing 0.005 to 1 part by weight of a triazole compound. Here, in the organopolysiloxane having two or more aliphatic unsaturated hydrocarbon groups bonded to silicon atoms in one molecule, which is component (1) above, the aliphatic unsaturated hydrocarbon groups include vinyl groups, allyl groups, etc. Examples of other monovalent hydrocarbon groups bonded to silicon atoms include methyl groups and phenyl groups. In this case, containing a phenyl group is advantageous for flame retardancy, but in the case of a roll for a copying machine, it has the disadvantage of poor releasability from toner, so the phenyl group should be contained within 5 mol%. It is desirable to keep it at . Also, instead of methyl group, 3,
It is also possible to use a 3,3-trifluoropropyl group oil, but although the oil resistance (dimethyl silicone resistance) is improved, there may be a problem in flame retardancy. Therefore, as the organopolysiloxane component (1), methylvinylpolysiloxane containing phenyl groups in a proportion of 5 mol % or less is desirable. The organopolysiloxane of component (1) is usually linear, but may be slightly branched. Also,
The aliphatic unsaturated hydrocarbon group may be present at either the molecular chain terminal or the side chain, or even both. Component (1), organopolysiloxane, may be used singly or as a mixture of two or more. In this case, in particular, in order to adjust the hardness of the silicone rubber after curing and reduce the amount of filler to improve workability and surface smoothness after roll forming, it is necessary to add one molecule of aliphatic unsaturated hydrocarbon group. It is preferable to mix an organopolysiloxane having three or more groups therein with an organopolysiloxane having aliphatic unsaturated hydrocarbon groups only at both ends, and thereby a crosslinking density can be obtained. In this case, the mixing ratio of both can be selected in various ways, but from 30 to
70% by weight: preferably 70 to 30% by weight. The viscosity of this organopolysiloxane is determined from the viewpoint of molding operations, regardless of whether it is a single component or a mixture.
Those having a viscosity at 25°C of 100 to 200,000 cs are used, preferably 200 to 100,000 cs. Next, the organohydrodiene polysiloxane, which is the component (2), acts as a crosslinking agent for the organopolysiloxane, which is the component (1).
It contains two or more ≡SiH bonds in the molecule, and may have a linear, branched, or cyclic structure. Specific examples of this organohydrodiene polysiloxane include those shown below. (However, a, b, c represent 0 or a positive integer, and d
indicates an integer greater than or equal to 2. )

【formula】

【formula】

【formula】

(However, R represents a hydrogen atom, methyl group, propyl group, or trimethylsilanol group.) In addition, when using a bifunctional organohydrodiene polysiloxane as the component (2), use it with the addition of a trifunctional or higher functional organohydrodiene polysiloxane (Japanese Patent Publication No. 47-40447), or
(1) It is necessary to use an organopolysiloxane containing a silicon atom-bonded aliphatic unsaturated hydrocarbon group having trifunctionality or more in the organopolysiloxane component. Furthermore, the amount of component (2) used is ≡ per silicon atom-bonded aliphatic unsaturated hydrocarbon group in component (1).
The amount is sufficient to provide 0.5 to 5 hydrogen atoms for SiH bonding, preferably 1 to 2 hydrogen atoms. Component (3), a fumed silica filler with a surface area of 50 m ² /g or more, is blended so that the fixing roll formed using this silicone rubber composition will have a predetermined hardness and strength. Fumed silica having a specific surface area of 50 m ² /g or more is used, and the surface is hydrophobized, or the surface is not treated. In this case, as the filler for the roll, use silica whose surface has been hydrophobized in advance, or use silica whose surface has been hydrophobized during the manufacturing process, as the fewer active sites on the surface the better the mold release durability. It is desirable to do so. Known hydrophobizing materials can be used, including dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, diphenylsilanediol, dimethyldimethoxyfuran, 1,3-divinyl-1,1,
Examples include 3,3-tetramethyldisilazane. The amount used is 3 to 30 parts by weight per 100 parts by weight of the organopolysiloxane of component (1), but preferably 5 to 15 parts by weight from the viewpoint of workability. Furthermore, in addition to the above-mentioned silica, as a filler, any filler commonly used in addition-type silicone rubber compositions can be used as long as it does not impair the surface smoothness, which is one of the purposes of the present invention. It is not preferable to use a large amount of a material with a diameter of 3μ or more.
Possible fillers include precipitated silica, carbon black, titanium dioxide, ferric oxide, aluminum oxide, zinc oxide, quartz powder, diatomaceous earth,
Examples include calcium citrate, talc, bentonite, asbestos, etc., and one or more of these may be blended. Furthermore, as the platinum or platinum compound which is the component (4), there may be mentioned those generally known as addition reaction catalysts, such as platinum black, or solid platinum supported on a carrier such as alumina or silica. , chloroplatinic acid, alcohol-modified chloroplatinic acid, a complex of chloroplatinic acid and olefin, and a complex of platinum and vinylsiloxane. When using these catalysts, it is preferable to crush them finely to improve their dispersibility, and to use carriers with small particle sizes and large specific surface areas. As for platinic acid or its complex with olefin, it is preferable to dissolve it in a solvent such as alcohol, ketone, ether or hydrocarbon. Note that the amount of this catalyst added is a catalytic amount, and may be adjusted as appropriate to obtain the desired curing speed, but from an economic standpoint and from the point of obtaining a good cured product, siloxanes such as chloroplatinic acid, etc. For those that are compatible with
The amount of platinum is 1 to 1 for the total amount of components (1) and (2).
For solid catalysts such as platinum black, the amount of platinum is preferably in the range of 20 to 500 ppm. Component (5), a triazole compound (flame retardant), has self-extinguishing properties in order for the roll to comply with UL-478 and for the silicone rubber cured product to pass UL-94 V-1 grade. It is an essential ingredient for imparting. Although many flame retardant imparting agents for silicone rubber compositions are known, in the case of addition-type silicone rubber, the addition curing reaction is often inhibited by the flame retardant imparting agent. However, since the triazole compound used in the present invention is effective in a small amount, there is no problem in practical curability. In this case, examples of the triazole compound include 1,2,3-triazole, 1,2,4-triazole, benzotriazole, and derivatives thereof.
Examples of 1,2,3-triazole and its derivatives include 1-methyl-1,2,3-triazole, 1-phenyl-1,2,3-triazole, 4-methyl-2-phenyl-1,2, 3-triazole, 1-benzyl-1,2,3-triazole, 4-hydroxy-1,2,3-triazole, 1-amino-1,2,3-triazole,
1-Benzamido-4-methyl-1,2,3-triazole, 1-amino-4,5-diphenyl-
1,2,3-triazole, 1,2,3-triazole-4-aldehyde, 4-cyano-1,2,
Examples include 3-triazole. 1, 2, 4
-Triazole and its derivatives include 1-methyl-1,2,4-triazole, 1,3-diphenyl-1,2,4-triazole, 5-amino-3-methyl-1,2,4-triazole, 3 −
Mercapto, 1,2,4-triazole, 1-phenyl-1,2,4-triazol-5-one,
Examples include 1-phenylurazole. Benzotriazole and its derivatives include 1-
Methylbenzotriazole, 5,6-dimethylbenzotriazole, 2-phenylbenzotriazole, 1-hydroxybenzotriazole, 1-
Examples include methyl benzotriazolecarboxylate. The most preferred of these is benzotriazole. The amount added is 0.005 to 100 parts by weight of component (1).
The amount is 1 part by weight, and if it is too small, there will be no effect, and if it is too large, there will be problems with curability. Note that component (5) may be used after being dissolved in an organic solvent such as isopropanol, ethanol, benzene, toluene, etc. in order to uniformly disperse it. The silicone rubber composition used in the present invention may optionally contain colorants, heat resistance improvers (red iron, black red iron, cerium oxide, etc.), addition reaction control agents (vinyl group-containing siloxane, acetylene compounds, etc.). etc.) etc. may be appropriately blended. Further, siloxane having a resin structure consisting of SiO ₂ units and R ₃ SiO _0.5 may be added as a reinforcing agent, and non-functional silicone oil may be added as a mold release agent. In the fixing roll of the present invention, a layer of the above-mentioned silicone rubber composition is formed on the outer peripheral surface of the roll body, and this is cured to form a cured rubber layer, or the cured composition is coated on the outer peripheral surface of the roll body. It can be manufactured by a known method such as adhesion to a surface, but in this case, the curing conditions for this silicone rubber composition are as follows:
Conditions of 3 to 15 minutes at a temperature of 100 to 150°C can be adopted, and post-curing can be performed at a temperature of 150 to 200°C for 30 minutes to 2 hours. The thickness of the rubber layer is selected as appropriate, and the shape, material, etc. of the roll body are also selected depending on the type of equipment. [Effects of the Invention] The fixing roll of the present invention has a surface rubber layer with low hardness and excellent surface smoothness and flame retardancy, and also has good moldability when forming the rubber layer, and is suitable for copying machines,
Suitable for use as various fixing rolls in facsimiles, printers, etc. Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the following examples. In addition, parts in the examples indicate parts by weight, and all viscosities indicate values at 25°C. Example 1 Both ends are blocked with dimethylvinylsiloxy groups,
50 parts of methylvinyl silicone oil whose main chain is dimethyl silicone units and a viscosity of 5000 cs, 100000 cs methyl vinyl silicone whose main chain contains 5 mol% of methyl vinyl siloxy units, others are dimethyl siloxy units, and the terminal is trimethyl siloxy units. 50 parts of oil, average composition formula Specific surface area of 9.5 parts of methylhydrodiene polysiloxane shown by 200 after hydrophobic treatment on the surface
10 parts m ² /g of fumed silica, 1 part of chloroplatinic acid
% isopropyl alcohol solution as platinum
An addition-type silicone rubber composition () was prepared by blending 0.03 part of a 50% ethanol solution of benzotriazole at 30 ppm. Next, after applying Primer No. 101 (manufactured by Shin-Etsu Chemical Co., Ltd.) to the surface of a cylindrical aluminum shaft with a diameter of 40 mm and a length of 400 mm and equipped with heating means inside, this outer peripheral surface was molded using an injection molding method. A layer (thickness: 2 mm) of the above silicone rubber composition was molded onto
Heat harden for 5 minutes, remove from the mold,
Post-cure at ℃ was performed for 1 hour. The silicone rubber layer of the fixing rubber roll obtained in this way has a JIS hardness of
40, and the surface smoothness was 0.8 μm or less. When a PPC copying machine was tested using this roll, it was possible to make 30,000 copies without using any silicone oil to prevent offset. In addition, using the addition type silicone rubber composition () used for this roll, 0.8 mm was measured at 120°C for 10 minutes.
Flame retardancy test (UL-94) for molded sheets and post-curing at 150℃ for 1 hour
When tested, it showed self-extinguishing properties equivalent to V-1. Example 2 Addition-type silicone rubber composition () was prepared by adding 5 parts of non-functional silicone oil with a viscosity of 1000 cs and 3 parts of red iron oxide as a heat resistance improver to the addition-type silicone rubber composition () used in Example 1. did. This was roll-molded in the same manner as in Example 1, and the performance of the silicone rubber layer of the resulting fixing rubber roll was examined, and the results showed that the JIS hardness was 40 and the surface smoothness was 1 μm or less. When this roll was subjected to a mounting test at a surface temperature of 170°C, it was possible to make 50,000 copies without using any silicone oil to prevent offset. In addition, a flame retardant test (UL-94 ) showed self-extinguishing properties equivalent to V-1.

Claims (1)

[Scope of Claims] 1. A fixing roll having a rubber layer formed on the outer peripheral surface of the roll body, the rubber layer comprising: (1) two aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule; 100 parts by weight (2) Organohydrodiene polysiloxane having two or more silicon-bonded hydrogen atoms in one molecule (1) Silicon atom per one aliphatic unsaturated hydrocarbon in component Sufficient amount to have 0.5 to 5 hydrogen atoms bonded to (3) Fumed silica filler with a specific surface area (BET method) of 50 m ² /g or more 3 to 30 parts by weight (4) Platinum or platinum compound Catalyst amount ( 5) A fixing roll characterized by using a cured product of an addition type silicone rubber composition containing 0.005 to 1 part by weight of a triazole compound. 2. The organopolysiloxane component (1) is a mixture of an organopolysiloxane having aliphatic unsaturated hydrocarbon groups only at both ends and an organopolysiloxane having three or more aliphatic unsaturated hydrocarbon groups per molecule. A fixing roll according to claim 1. 3. The fixing roll according to claim 1 or 2, wherein the triazole compound as component (5) is benzotriazole.