JPH1078721A - Roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll which exhibits surpassing performance as a thermal pressure fixing roll of an electrostatic copying machine. SOLUTION: The non-tacky coating layer of the roll having a rigid core and the non-tacky coating layer is formed by bringing a silane compd. having the hydrogen atoms bonded with silicon atoms and hydrolysis groups into hydrosilylation addition reaction with fluororubber contg. radical reactive unsatd. bonds to obtain silane modified fluororubber, then crosslinking this silane modified fluororubber by hydrolyzable polycondensation reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll having a rigid core and a non-adhesive coating layer, and more particularly to a roll exhibiting excellent performance as a hot-press fixing roll of a dry electrostatic copying machine, a laser printer or the like.

Conventionally, in a fixing system such as a dry electrostatic copying machine or a laser printer, a hot-press roll having a metal core and a non-adhesive coating layer has been generally used. As the material of the non-adhesive coating layer of the hot-press fixing roll, fluorine resin (USP 3,268,351), dimethyl silicone rubber (USP 3,666,247), and JP-A-52-46.
819), phenyl silicone rubber (JP-A-59-20)
9129), fluorosilicone rubber (JP-A-3-26
947), fluororubber (JP-A-55-135876) and the like have been proposed, and some of them have been put to practical use.

However, all of these materials do not have sufficient non-adhesiveness to the dry developing toner, so that a so-called oil phase method in which silicone oil is always supplied to the roll surface has been forced.

[0004] Fluororesin coatings generally show good non-adhesiveness, but have the disadvantage of poor wetting with silicone oil and being hard and poor in rubber elasticity, giving unnecessary gloss to the copy surface. The dimethyl silicone coating absorbs the silicone oil when heated and swells, possibly leading to destruction. Although the phenyl silicone rubber coating has improved silicone oil resistance, it has a problem of non-adhesion to toner. The fluorosilicone rubber coating has sufficient silicone oil resistance, but has poor heat resistance and physical strength, and has a maximum use temperature of about 180 ° C.
However, it cannot withstand the surface temperature of the fixing roll of 230 ° C. required for the current high-speed copying machine. In addition, the fluororubber coating withstands a temperature of 270 ° C. for ordinary use and is not at all affected by hot silicone oil, but requires a large amount of silicone oil to be supplied due to poor non-adhesiveness.

Therefore, in order to improve the affinity between the fluororubber and the silicone oil, a method of mixing and dispersing a modified silicone oil in the fluororubber (JP-A-3-2859)
34), a method in which a fluororubber roll is post-treated with a modified silicone oil after molding (JP-A-6-175532) has been proposed. The products of these methods are amino-modified silicone oil, mercapto-modified silicone oil, Since the heat resistance of the modified silicone oil or the like is poor and easily deteriorates even at a temperature around 230 ° C., there is a disadvantage that the affinity of the roll with the silicone oil is rapidly lost. Also, mechanical blending of fluoro rubber and silicone rubber has been attempted, but this blend has drawbacks in processability, and it seems that a copolymer type blend of fluoro rubber and silicone rubber is being studied, but should be seen No results have been obtained.

The present inventor has previously described a fixing roll which does not have the above-mentioned drawbacks of the fixing roll according to the prior art and exhibits excellent performance as a hot-press fixing roll of an electrostatic copying machine.
The non-adhesive coating layer is subjected to a radical addition reaction of a fluorine-containing rubber containing iodine and / or bromine (peroxide-crosslinked fluorine-containing rubber) with a silane compound having a group containing a radical-reactive unsaturated bond and a hydrolyzable group, thereby modifying the silane with silane. There has been proposed a fixing roll formed by obtaining a fluororubber and then crosslinking the silane-modified fluororubber by a hydrolytic polycondensation reaction (1995 Patent Application No. 35854).

[0007]

An object of the present invention is to provide further technical means which can replace the technical means proposed in the above-mentioned Japanese Patent Application No. 35854/1995.

[0008]

According to the present invention, a non-adhesive coating layer of a roll having a rigid core and a non-adhesive coating layer is added to a fluorine-containing rubber containing a radical-reactive unsaturated bond by a silicon atom. A silane compound having a hydrogen atom and a hydrolyzable group bonded to a silane compound is subjected to a hydrosilylation addition reaction to obtain a silane-modified fluororubber, and then the silane-modified fluororubber is crosslinked by a hydrolytic polycondensation reaction. According to the above-mentioned 1995 Patent Application No. 35854
It is possible to obtain a fixing roll having performance comparable to that of the fixing roll proposed in the above item.

Hereinafter, the present invention will be described in more detail. The fluororubber containing a radical-reactive unsaturated bond used in the present invention is a fluororubber containing a fatty attribute carbon-carbon unsaturated bond at a molecular chain terminal and / or a side chain, and is available from Asahi Glass Industry Co., Ltd. Ltd. of fluorine rubber "AFLAS ^TM" 1
00H, S and 200 series fluororubbers. Here, 100 series is an ethylene tetrafluoride-propylene binary copolymer, and 200 series is an ethylene tetrafluoride-vinylidene fluoride-propylene terpolymer. As in the case of the peroxide crosslinked fluororubber contained as
It can be cured by heat using an organic peroxide crosslinking agent such as 2,5-dimethyl-2,5-di-t-butylperoxyhexane and generally in the presence of a crosslinking aid such as triallyl isocyanurate. Note that A is a fluorine rubber brochure item Asahi Glass Co., is a manufacturer of "AFLAS", "vulcanizable against peroxide AFLAS"
Fras has no functional group such as a double bond, and is thermally and chemically
Although it is described as a chemically stable polymer, the measurement results of the infrared characteristic absorption of the present inventors show characteristic absorption (wave number 1600 cm ^-1 ) corresponding to an aliphatic C = C bond.

The silane compound having a hydrogen atom bonded to a silicon atom and a hydrolyzable group used in the present invention includes, for example, the general formula HSiR _3-n X _n (where R is an inert group such as methyl or phenyl) , X is a hydrolyzing group, generally, an alkoxyl group such as methoxyl and ethoxyl, n
Is 1, 2 or 3. )). X also represents a methyl ethyl ketoxime group (deoxime reaction), an acetoxyl group (deacetic acid reaction), an islopenyloxy group (deacetone reaction), an amino group (deamine reaction), an amide group (amide reaction), It may be a silazane group (deammonification reaction) or the like. The following compounds are commercially available and can be easily obtained. Trimethoxysilane _{(CH 3 O) 3 SiH T} -2895 manufactured by Chisso Corporation; triethoxysilane _{(C 2 H 5 O) 3} Si
H LS-525, diethoxysilane (C ₂ H
₅ O) ₂ SiH ₂ LS-1380 and tetramethyldisilazane HSi (CH ₃ ) ₂ NHSi (CH ₃ )
₂ H LS-7050 manufactured by Shin-Etsu Chemical Co., Ltd., bis (dimethylamino) monomethyl silane HSiCH
₃ [N (CH) ₃ ] ₂ B-2250 manufactured by Chisso Corporation

As schematically shown below, the hydrosilylation addition reaction of a silane compound having a hydrogen atom bonded to a silicon atom to a radical reactive unsaturated bond represented by an aliphatic carbon-carbon unsaturated bond is carried out by The reaction proceeds easily in the presence of a noble metal catalyst such as hexachlorochloroplatinic acid as shown in the following reaction formula (USP-2,82
3, 218).

Embedded image {SiH + CH ₂ ＣＨCH—} → ──────SiCH ₂ CH ₂ —Silicon atom to fluororubber containing aliphatic carbon-carbon unsaturated bond in main chain and / or side chain A hydrosilylation addition reaction of a silane compound having a hydrogen atom bonded to a compound is also known, and seems to proceed as schematically shown by the following reaction formula (JP-A-6-192524: Bayer).

Embedded image The above reaction is carried out under an inert gas atmosphere or in a closed system for about 1 hour.
By heating to 50-160 ° C for 15-20 minutes
Is preferred. In addition, this reaction is similar to chloroplatinic acid.
It is common to use a noble metal catalyst, but the radical
The presence of peroxide, heating or
Is promoted by irradiation of ionizing radiation such as ultraviolet rays and electron beams
You can also.

The silane-modified fluororubber thus obtained is dissolved in an appropriate solvent, applied to a rigid core, and left at room temperature to undergo hydrolytic polycondensation due to the action of moisture added to the solution or moisture in the air. It reacts and cures. It is believed that the formation of three-dimensional crosslinks by the hydrolytic polycondensation reaction proceeds in the following manner.

Embedded image Generally, a catalyst is used to promote the hydrolytic polycondensation reaction. As the catalyst, an acid such as acetic acid, a base such as triethanolamine, n = butylamine or an organic acid salt such as zinc, tin, cobalt or iron such as lead octanoate or dibutyltin dilaurate is used.

The properties of the roll of the present invention can be further improved by incorporating the following substances as co-crosslinking agents. Incidentally, the term "co-crosslinking agent" as used herein, refers broadly silane-modified fluororubber hydrolytic polycondensation compounds that can be incorporated into the reaction, thus (CH _{3) 3} monofunctional compounds such as SiOCH ₃ Including. 1) Improvement in affinity with silicone oil 1-1) Compound having a methylsiloxane group together with a hydrolyzable group CH ₃ Si (OCH ₃ ) ₃ TSL-8113, (CH
₃ ) ₂ Si (OCH ₃ ) ₂ TSL-8112 and
(CH ₃ ) ₃ SiOCH ₃ TSL-8111 manufactured by Toshiba Silicone Co., Ltd .; (CH ₃ ) ₃ SiOH LS-310
Shin-Etsu Chemical Co., Ltd .; (CH ₃ ) ₂ CHCH ₂ Si
(OCH ₃ ) ₃ AY-43-048 and (CH
_{3 O) 3 Si (CH 2} ) 6 Si (OCH 3) 3 AY-
43-083 Toray Silicone Co., Ltd. 1-2) Modified silicone oil SiH group-containing silicone oil L-31, FZ-38
05 and FZ-3702 manufactured by Nippon Unicar Co., Ltd .;
SiOH group-containing silicone oil FZ-3122
And L-9000; SiO (alkyl) group-containing silicone oil FZ-3701, FZ-3704 manufactured by Nippon Unicar Co., Ltd. 1-3) Room temperature curing type silicone rubber Deacetic acid type KE42 RTV, deoxime type KE45
RTV, Deacetone type KE347RTV and Dealcohol type KE4895 Shin-Etsu Chemical Co., Ltd .;
Amide type BA-10 manufactured by Bayer AG 2) Improvement of releasability from toner Fluoroalkyl group-containing compound CF ₃ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ XC-95-
418, CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ Si (OCH
₃ ) ₃ XC-95-468, CF ₃ (CF ₂ ) ₇ (C
_{H 2) 2 Si (OCH 3} ) 3 XC-95-470 and _{CF 3 (CF 2) 7 (} CH 2) 2 SiCH 3 (OC
H ₃ ) ₂ XC-95-472 Toshiba Silicone Co., Ltd.
C ₈ F ₁₇ SO ₂ NPr (CH ₂ ) ₃ Si (OCH
₃ ) ₃ MF-160 manufactured by Mitsubishi Materials Corporation 3) Control of chargeability Polyether group-containing compound MAC-2301 manufactured by Nippon Unicar Co., Ltd.

The properties of the rolls of the present invention can be further modified by incorporating conventional ingredients for fluororubber as exemplified below. Filler for improving physical properties of rubber: MT black, FT black, powdered silica, powdered quartz, etc. Conductivity imparting agent: Ketchen-black
EC), acetylene black, carbon fiber, conductive ceramics, whiskers, metal powders, conductive metal coating powders, etc. Dielectric property modifiers: high dielectric ceramics (barium titanate, strontium), organic high dielectric substances, etc. Properties modifier: metal powder, ceramic powder, metal oxide, etc. Heat resistance improver: oxides and hydroxides of metals such as MgO, PbO, Ca (OH) _2, etc. Antistatic agent: surfactant, etc. Agent: mica powder etc. Processability imparting agent: low molecular weight liquid fluoro rubber (Daiel G-
101; Daikin Chemical Industries, Ltd.), fluorosilicone oil, fluorosilicone rubber, perfluoroalkyl vinyl ether-containing fluorinated oil (Demnum ^™ ; Daikin Industries, Ltd.) Compatibilizers: silicone rubber, silicone oil, modified silicone oil, silicone resin, silicone varnish , Silicone rubber powder, etc. Others: polyterafluoroethylene resin, PFA (terafluoroethylene-perfluorovinyl ether copolymer) resin, FEP (terafluoroethylene-hexafluoropropylene copolymer) resin, low molecular weight polyterafluoroethylene resin , Oligo-tetrafluoroethylene, reactive perfluoroalkylating agent and perfluoroalkyl compound, fluoroether compound, fluoroalkylvinyl ether compound, fluorocarbon System surfactant, etc.

There are no particular restrictions on the amounts of the co-crosslinking agent, water and catalyst that are incorporated during curing of the silane-modified fluororubber at room temperature.
The silane-modified fluororubber is usually cured at room temperature and then post-cured (post-cured) at a high temperature in an inert gas atmosphere or in a vacuum, but the conditions are not particularly limited.

The roll of the present invention may have a single-layer structure having only a vulcanized silane-modified fluororubber layer as a non-adhesive coating layer. For example, the roll may have a multilayer structure having an intermediate layer made of a heat-resistant rubber. It can also be. As the heat-resistant rubber, EPT, acrylic rubber, silicone rubber, fluorosilicone rubber, fluororubber and the like are used. The intermediate layer may be spongy. As can be easily understood by those skilled in the art, the silane-modified fluororubber of the present invention is processed into a non-adhesive belt by applying and vulcanizing a belt-shaped metal sheet, plastic sheet, rubber sheet, cloth, or the like. It can also be used.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Comparative example Fluorine rubber [AFLAS ^™ 100H Asahi Glass Industry Co., Ltd.
20 parts by weight of MT carbon black to 100 parts by weight
4.0 parts by weight of triallyl isocyanurate (manufactured by Taiku ^TM Nippon Kasei Co., Ltd.) and 1.05 parts by weight of peroxide (manufactured by Perbutyl P ^TM manufactured by Nippon Oil & Fats Co., Ltd.) were added, and the mixture was sufficiently kneaded with a two-roll rubber mill. And dissolved in a solvent, tetrahydrofuran, to obtain a solution having a solid content of 33% by weight. On the other hand, an aluminum (core) core having a diameter of 59.0 mm
After washing with 1-trichloroethane, a silicone primer was applied to the surface, and a thermosetting silicone rubber tape having a JIS hardness of 60 ° was wound thereon and hot-pressed in a mold to obtain a silicone rubber roll having a diameter of 62.0 mm. . After grinding the surface of the roll to adjust the diameter to 60.0 mm, the surface was coated with Chemrock ^™ 607 (HughsonCe).
(made by Micals) primer was applied and air-dried for 2 hours.
Next, the silicone rubber roll is spray-coated with the non-silane-modified fluororubber solution prepared as described above, and after volatilization of the solvent, a heat-curing treatment is performed at 180 ° C. for 30 minutes in a nitrogen gas atmosphere. A comparative roll having a membrane was obtained.

EXAMPLES Example 1 Fluoro rubber [Afras ^™ 100H Asahi Glass Industry Co., Ltd.
100 parts by weight, silane compound LS-1380
[Shin-Etsu Chemical Co., Ltd.] 5 parts by weight, 2 parts by weight of a 1% by weight alcohol solution of chloroplatinic acid, and 20 parts by weight of MT-carbon black were thoroughly kneaded with a two-roll rubber machine, and
Heat press treatment was performed at 20 ° C. for 15 minutes to obtain a silane-modified fluororubber. This modified fluororubber was dissolved in a solvent previously dehydrated, tetrahydro, to obtain a solution having a solid content of 33% by weight. Separately, 7 parts by weight of dibutyltin dilaurate and 2 parts by weight of purified water were added to 100 parts by weight of tetrahydrofuran to prepare a catalyst-water-containing liquid. A mixture obtained by adding 10 parts by weight of this catalyst-water-containing solution to 100 parts by weight of the silane-modified fluororubber solution having a solid content of 33% by weight and sufficiently stirring the mixture was subjected to a silicone rubber roll in the same procedure as in the comparative example . After spraying and leaving at room temperature for 3 days,
After vulcanization at 200 ° C. for 4 hours, the roll of the present invention was obtained.

Example 2 A roll of the present invention was prepared in the same procedure as in Example 1 , except that the following co-crosslinking agent was added to a mixture of a silane-modified fluororubber solution and a catalyst-water-containing solution. . Addition amount (parts by weight) of co-crosslinking agent 2-1 TSL-8112 Toray Silicone Co., Ltd. 8 2-2 TSL-8112 4 XC-95-470 Toshiba Silicone Co., Ltd. 6 2-3 TSL-8112 4 MAC-2301 Japan Unicar Co., Ltd. 4 2-4 TSL-8112 3.0 XC-95-470 4.5 MAC-2301 3.0

[002000] comparison test Comparative Example and Example 1 and Example 2 (2-1, 2-2,
The rolls prepared in 2-3 and 2-4) were used as A4 sheets of a type in which silicone oil was constantly applied to a hot-press fixing roll.
Horizontal type, 50 sheets / min dry electrostatic copying machine [NP-755
0; manufactured by Canon Co., Ltd.] as a hot-press fixing roll, the degree of contamination of the roll surface with toner was observed by an actual running test, and the final durability life (number of copies) was evaluated. The test results were as shown in the table below. Example No. Final durability life (sheets) Comparison Example 13,000 Example 1 122,000 Example 2 2-1 175,000 2-2 182,000 2-3 187,000 2-4 217,000 the above test results, when according to the present invention, which compared with the unmodified fluororubber (Comparative example), without a co-crosslinking agent (example
1 ) also shows that the final durability life is slightly more than 9 times, and when the co-crosslinking agent is used (Example 2), the final durability life is about 14 to 18 times. The fixing roll of the present invention has a remarkably improved final durability life equivalent to that of the fixing roll previously proposed in Japanese Patent Application No. 7-35854.

The hot-press fixing roll of the present invention has a long service life and a high affinity with silicone oil, and can be easily manufactured without using special working conditions or special materials which are difficult to obtain. Can be.

Claims (6)

[Claims] 1. A roll having a rigid core and a non-adhesive coating layer, wherein the non-adhesive coating layer is formed by adding a hydrogen atom bonded to a silicon atom and a hydrolyzable group to a fluororubber containing a radically reactive unsaturated bond. A roll obtained by subjecting a silane compound having the following formula to a hydrosilylation addition reaction to obtain a silane-modified fluororubber, and then crosslinking the silane-modified fluororubber by a hydrolytic polycondensation reaction. 2. The roll according to claim 1, wherein the radically reactive unsaturated bond contained in the fluororubber is an aliphatic carbon-carbon double bond. 3. The roll according to claim 1, wherein the crosslinking is carried out at room temperature. 4. The method according to claim 1, wherein the crosslinking is carried out in the presence of a hydrolyzable silane compound having a fluoroalkyl group, a methylsiloxane group and / or a polyether group as a co-crosslinking agent. roll. 5. The roll according to claim 1, which is a hot-press fixing roll of a fixing device of a dry electrostatic copying machine. 6. The roll according to claim 1, which is a backup roll for a fixing device of a dry electrostatic copying machine.