JP3340285B2 - Method for modifying peroxide-crosslinked fluororubber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the affinity of peroxide-crosslinked fluororubber with silicone oil. Also, the present invention has a vulcanized peroxide-vulcanized fluororubber having improved affinity for silicone oil by the above method as a non-adhesive coating layer, and is particularly suitable for use as a hot-press fixing roll of a dry-type electronic copying machine. About rolls.

Conventionally, as a fixing system of a dry electrostatic copying machine, a heat and pressure fixing by a heat roll having a metal core and a non-adhesive coating layer has been generally adopted. Materials for the non-adhesive coating layer of this hot-press roll include fluororesin (USP 3 268 351), dimethyl silicone rubber (USP 3 666 247) and JP-A-52-46.
No. 819) and phenyl silicone rubber (JP-A-59-2).
09129), fluorosilicone rubber (Japanese Unexamined Patent Publication No.
No. 26947), fluorine rubber (JP-A-55-13587).
No. 6) have been proposed, and some of them have been put to practical use.

However, since these materials do not have sufficient non-adhesiveness to dry developing toner, in order to extend the durability life of the fixing roll, a so-called oil fuse system in which silicone oil is always supplied to the roll surface. Has been forced to adopt.

[0004] Fluororesin-coated rolls generally exhibit good non-adhesiveness and do not necessarily require the supply of silicone oil, but have the drawback of imparting unnecessary gloss to the copy surface due to the hard surface and poor rubber elasticity. When silicone oil is used, unevenness in fixing occurs due to repelling of the oil. The dimethyl silicone rubber-coated roll swells when dimethyl silicone absorbs silicone oil when heated,
It deteriorates early and becomes unusable. Although the phenyl silicone rubber coating has improved silicone oil resistance, non-adhesion to toner tends to decrease.
Fluorosilicone rubber coating has sufficient silicone oil resistance, but is poor in non-adhesion, heat resistance and physical strength, especially its maximum use temperature is about 180 ° C,
It cannot be used at the roll surface temperature of 230 ° C. of the hot-press fixing roll required for current high-speed copying machines.

Further, the fluororubber coating withstands the temperature of 270 ° C. for ordinary use and is not attacked by thermal silicone oil at all. Requires supply. Therefore, various attempts have been made to improve the affinity of fluororubber with silicone oil, for example, the blending of amino-modified silicone oil with fluororubber (JP-A-3-285934) and the post-treatment of fluororubber with amino-modified silicone oil ( JP-A-6-175532
), Treatment with a mercapto-modified silicone oil (JP-A-59-4699), and other modification with organosiloxanes (JP-A-4-30878, JP-A-4-3)
No. 08879) has been proposed. Further, blends of fluorine rubber and silicone rubber, copolymerization types of fluorine rubber and silicone rubber, and the like have been proposed, but all have problems.

For example, when a modified silicone oil is blended or post-treated with a modified silicone oil, the amino-modified silicone oil and the mercapto-modified silicone oil used have poor heat resistance. As a result, the toner deteriorates in affinity with the silicone oil and loses affinity with the silicone oil, causing toner adhesion and paper wrapping, and at the same time causes over-vulcanization of the fluororubber, causing the fluororubber coating layer to collapse and peel off from the core. In addition, these modified silicone oils have hygienic problems.
Further, it is difficult to process a blend of a fluororubber and a silicone rubber, and a copolymer type of both has not been put to practical use.

[0007]

Accordingly, an object of the present invention is to provide a method for improving the affinity of peroxide-crosslinked fluororubber with silicone oil without impairing its excellent non-stickiness, high rubber elasticity and heat resistance. It is in. Another object of the present invention is to provide a roll having excellent non-adhesiveness, high rubber elasticity and heat resistance and exhibiting remarkably improved affinity for silicone oil and exhibiting excellent performance as a hot-press fixing roll of a dry type electronic copying machine. To offer.

[0008]

Means for Solving the Problems In the present invention. In order to achieve the above object, at least one of a methylsiloxane compound containing a halogen atom and / or a hydrogen atom and a group having an ethylenically unsaturated bond bonded to a silicon atom as a reactive group is reacted with a peroxide crosslinked fluororubber. In a preferred embodiment of the present invention, this reaction is carried out simultaneously with vulcanization by blending the methylsiloxane compound with an unvulcanized peroxide-crosslinked fluororubber composition. Alternatively, it is also possible to use a method in which the surface of an unvulcanized, semi-vulcanized or vulcanized peroxide cross-linked fluororubber molded article is coated with or impregnated with the methylsiloxane compound and reacted.

Hereinafter, embodiments of the present invention will be described in detail. As a method of crosslinking fluororubber, crosslinking methods utilizing characteristics of polymers such as amine crosslinking, polyol crosslinking, and peroxide crosslinking have been developed, and polymers suitable for each crosslinking method have also been developed.

The peroxide type fluoro rubber to be used in the present invention includes vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-propylene copolymer A fluororubber of the type in which halogens, especially bromine and / or iodine, and hydrogen atoms are introduced into the terminal and side chains of the polymer molecular chain, etc., and the crosslinking is carried out by an abstraction reaction of halogen atoms and hydrogen atoms. In the practice of the present invention, crosslinking of the rubber composition is carried out by a conventional method, that is, using a radical generator represented by an organic peroxide compound as a crosslinking agent and a crosslinking assistant, generally triallyl isocyanurate.

There are no particular restrictions on the group having an ethylenically unsaturated bond bonded to a silicon atom, a methylsiloxane compound containing a halogen atom and / or a hydrogen atom as a reactive group used in the practice of the present invention. (Compounds shown below are all products of Shin-Etsu Chemical Co., Ltd., and symbols consisting of alphanumeric characters are the product names of the companies). A) methyl includes groups with an ethylenically unsaturated bond siloxane _{R-Si (CH 3) 2} O [Si (CH 3) 2 O ] _n Si (CH _{3) 2} -
RR R contains an isopropenyl group and has a C-Sik bond to form S
organic group attached to i atom (further details are not clear)
X-22-164B, X-22-164C CH ₂ ＣCCH ₃ COOC ₃ H ₃ H ₆ Si- (OSi CH
₃ ) ₃ X-22-5002 (CH ₃ ) ₃ SiO [Si (CH ₃ ) ₂ O] _n Si (CH ₃ ) ₂ -R
_{X-22-174D (CH 3) 3} Si O (Si HCH 3 O) 2 Si (CH 3) 3
LS-8630 _{[(CH 3) 3 SiO] 3} Si H LS-8650 - (Si HCHO) n - methylsiloxane [(CH ₃ including KF-99 B) reactive halogen _{atoms) 3 Si O] 3 Si (} CH ₂ ) ₃ I LS-870
0 C) methylsiloxane containing reactive hydrogen atoms _{[HSi (CH 3) 2] 2} O LS-7040 _{[HSi (CH 3) 2 O]} 2 Si (CH 3) 2 LS-8130 HSi (CH 3) 2 OSi (CH ₃ ) ₃ LS-7060 The methylsiloxane compound suitably used in the present invention includes chloro, chloroalkyl, phenyl, together with a group having an ethylenically unsaturated bond, a reactive halogen atom and / or a reactive hydrogen atom. , Polyether, methylstyryl, cyanoalkyl, trifluoropropyl, perfluoroalkyl, and the like, and methylsiloxane compounds having non-reactive groups at the terminals and / or side chains. Can be used for

The mixing ratio of the methylsiloxane compound to the peroxide-crosslinked fluororubber is not particularly limited, and is generally 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of the former. There is no particular limitation on the amount of the peroxide-crosslinked fluororubber molded article to be applied or impregnated on the surface, as long as the surface can be uniformly coated. The methylsiloxane compound exemplified by the above compound is a viscous liquid at normal temperature and can be applied as it is to the surface of a fluororubber molded product. It can also be applied in the form of a solution.

Further, in the practice of the present invention, the following substances can be added to the peroxide-crosslinked fluororubber in order to impart or modify specific properties. Rubber mechanical property improver: carbon racks such as MT and FT, dry and wet silica, quartz powder, etc. Conductivity imparting agent: Ketchen ^™
EC), acetylene blacks, carbon fiber,
Conductive metal coating powder, conductive inorganic and ceramic powder, metal whisker powder, etc. Antistatic agent: various antistatic agents, surfactants Abrasion resistance improver: for example, mica powder, etc. Processability improver: thermoplastic fluoro rubber (DAI-EL ^TM
Thermoplastics), low molecular weight liquid fluororubber (Daiel ^™ G-101), fluorosilicone oil and fluorosilicone rubber, fluoro oil compatibility improver, heat-resistant additive: silicone oil and reactive silicone oil, silicone resin, silicone Coupling agent Dielectric property controlling agent: Ceramics such as barium titanate and strontium titanate and organic high dielectric substance High thermal conductivity imparting agent: Metal powder, ceramic powder and various metal oxide powder Heat resistance improving agent: MgO, Ca ( OH) ₂ , metal oxides and hydroxides such as PbO, organic amine compounds, etc .: PFA (tetrafluoroethylene-perfluorovinylether copolymer resin), FEP (tetrafluoroethylene-hexafluoropropylene copolymer resin) ),
Tetrafluoroethylene oligomers and reactive perfluoroalkylating agents, and perfluoroalkyl compounds, fluoroether compounds, fluoroalkylvinyl ether compounds, etc.

The primary vulcanization conditions and the secondary vulcanization (post-cure) conditions of the fluororubber composition in the method of the present invention can be appropriately changed. The standard oven heating condition is 180 ° C. × 4 hours, but there is no problem even at 250 ° C. × 24 hours. Further, the primary vulcanization and the secondary vulcanization can be carried out in a vacuum or in an inert gas such as carbon dioxide, helium, argon or nitrogen. Radiation can also be used in primary and / or secondary vulcanization. If desired, UV irradiation or fluorine gas treatment can be applied to the crosslinked rubber.

Hereinafter, the present invention will be described in more detail with reference to Comparative Examples and Examples. However, these examples are intended only to facilitate understanding of the present invention, and limit the scope of the present invention. Not something.

[ Comparative Example ] Peroxide crosslinked fluororubber (Daiel ^MT G-801, Daikin Chemical Industries) 10
0 parts by weight, 20 parts by weight of MT carbon black, 4.0 parts by weight of triallyl isocyanurate (Taik ^™ , Nippon Kasei), 2,5-dimethyl-2,5-di-t-butylperoxyhexane (Perhexa ^™ 2)・ 5B, Nippon Oil & Fat)
Five parts by weight were sufficiently kneaded with a two-roll mill for rubber, and a 1.5 mm-thick sheet was prepared from the obtained compound using a calender. Next, an aluminum core (core metal) having a diameter of 59.0 mm was washed and degreased with 1,1,1-trichloroethane, and Chemlock 60 was used as an adhesive on the roll surface.
7 (Huguson Chemical Co.) was applied, and after air-drying for 2 hours, the above-mentioned sheet was wound and heated and pressed in a roll forming mold at 160 ° C. for 20 minutes to obtain a rubber roll having a diameter (outer diameter) of 62 mm. . The rubber roll was secondarily heated at 200 ° C. for 4 hours, cooled, and then cooled to an outer diameter of 60.0 mm.
mm was subjected to a surface grinding finish.

[0017] [implementation example] except added blending various siloxane compound of 3.0 parts by weight in total rubber compounds shown in Comparative Examples, were prepared rubber roll finish in the same procedure as Comparative Example. Type and amount Example No. siloxane compound The amount of the methyl siloxane compound (parts by weight) 1 X-22-174D 3.0 (unsaturated group-containing type) 2 LS-8700 3.0 (halogen-containing type) 3 LS-8630 3.0 (hydrogen atom containing type) 4 X-22-174D 1.5 LS-8700 1.5 5 X-22-174D 1.5 LS-8630 1.5 6 LS-8700 1.5 LS -8630 1.57 X-22-174D 1.0 LS-8700 1.0 LS-8630 1.0

[0018] The roll and roll of Examples 1 to 7 of the Performance Test Comparative Example Comparative tests have been carried out in performance. In the test, each of the rolls was mounted as a hot-press fixing roll on an oil fuse type dry electrostatic copying machine NP-7550 manufactured by Canon Inc.
The number of copies until the contamination of the roll surface by the toner and thus the contamination of the copy surface exceeded a certain limit was evaluated as the final life. The results were as shown in the table below.

Example No. Comparative Example Example 1 2 3 Final Life 12.3 192 163 176 ( × 10 ³ sheets) Example (Continued ) 4 5 6 7 172 153 161 161 169

[0020]

As shown in the above table, according to the present invention, the final life of the hot-press fixing roll of the dry electrostatic copying machine can be remarkably extended (by an order of magnitude).

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 8/00-8/50

Claims (5)

(57) [Claims] The present invention is characterized in that a peroxide-crosslinked fluororubber is reacted with at least one of a methylsiloxane compound containing a halogen atom and / or a hydrogen atom as a group having an ethylenically unsaturated bond bonded to a silicon atom as a reactive group. To improve the affinity of the peroxide crosslinked fluororubber with silicone oil. 2. The peroxide-crosslinked fluororubber is blended with at least one of a group having an ethylenically unsaturated bond as a reactive group and a methylsiloxane compound containing a halogen atom and / or a hydrogen atom. the method of. 3. A surface of a peroxide-crosslinked fluororubber molded article is contacted with at least one of a group having an ethylenically unsaturated bond bonded to a silicon atom as a reactive group and a methylsiloxane compound containing a halogen atom and / or a hydrogen atom. The method of claim 1, wherein the reacting is performed. 4. A roll having a rigid core and a non-adhesive coating layer, wherein the non-adhesive coating layer has a group having an ethylenically unsaturated bond bonded to a silicon atom as a reactive group, a halogen atom and / or a hydrogen atom. A roll comprising a peroxide-crosslinked fluororubber vulcanizate having at least a surface having improved affinity for silicone oil by reacting at least one methylsiloxane compound containing: 5. The roll according to claim 4, which is a hot-press fixing roll or a backup roll of a dry electrostatic copying machine.