Shin-etsu Chemical Co., Ltd.

Ricoh Company, Ltd.

Nobuyuki Hasebe

Minoru Takamizawa

Yasuo Asahina

Setsuo Soga

Yasuaki Hara

Hisashi Aoki

Kiyoshi Imai

Kiyohiro Kondow

Ichiro Fukushima

Takeshi Mihama

Tomiaki Asami

Kiyohiro Kondo

Humio Okada

Hiroshi Sugawara

Hiromi Toida

So-called addition-type curable organopolysiloxane compositions curable by the hydrosilation reaction between vinyl groups of a dimethylpolysiloxane and hydrogen atoms directly bonded to the silicon atoms in a methylhydrogenpolysiloxane in the presence of a platinum catalyst can be imparted with a greatly increased pot life to have improved workability when the composition is admixed with a halogen- or alkoxy-substituted olefinic organic compound such as allyl halides, 1,3- and 2,3-dihalogenopropenes, 2-alkyl-3-halogenopropenes, 1,3- and 1,4-dihalogenobutenes-2 and alkyl allyl ethers as a moderator of the crosslinking reaction without any adverse effect on the curability of the composition.

Curable organopolysiloxane composition

The invention provides an improvement of a room temperature-curable silicone rubber composition cured by the mechanism of the condensation reaction between terminal silanolic hydroxy groups of a diorganopolysiloxane and an organosilicon compound having at least three alkoxy groups per molecule in the presence of an organotin compound as a catalyst to form crosslinks in respect of the remarkably small permanent compression set as well as excellent heat resistance of the cured rubbery elastomer thereof. Different from conventional compositions of the above mentioned type containing some organotin compound as the curing catalyst, the inventive composition preferably contains very specific organotin compound as the curing catalyst, which is represented by the general formula R.sub.2 R.sup.1 Sn-O-SnR.sup.1 R.sub.2 or R.sub.2 SnR.sub.2.sup.1, in which R is a monovalent hydrocarbon group and R.sup.1 is an acid residue of a monoalkyl ester of a dibasic carboxylic acid such as MeOCOCH.dbd.CHCOO-- and the like, in a limited amount. The composition may further contain an inorganic filler, of which the neutral surface condition is important in order that the composition may have good curability to give a cured rubbery elastomer exhibiting a small permanent compression set. A limited content of silicon-bonded vinyl group in the diorganopolysiloxane, the balance being methyl groups, is effective to improve the heat resistance of the cured rubber.

Room temperature curable silicone rubber composition

A fixing roll for electrophotography having a surface layer of a cured room-temperature-vulcanizing silicone rubber composition comprising a mixture consisting of two diorganopolysiloxanes, one of which is terminated at the chain ends with silanol groups and has a relatively high viscosity, and the other of which is terminated at the chain ends with trialkyl silyl groups and has a relatively low viscosity, an alkoxysilane or a partial hydrolysis-condensate thereof as the crosslinking agent, a metal salt of an organic acid as the reaction catalyst, and three kinds of inorganic fillers, namely, calcium carbonate, iron oxide, and titanium dioxide, and containing substantially no siliceous fillers. The fixing rolls have excellent properties including, in particular, the ability to provide a long copy-life to electrophotographic copying machines.

Fixing roll for electrophotography

Anti-sticking silicone compositions comprising (a) a diorganopolysiloxane of substantially straight-chain molecular structure having vinyldimethylsilyl terminal groups at both chain ends, (b) a diorganopolysiloxane of substantially straight-chain molecular structure having hydrogendimethylsilyl terminal groups at both chain ends, (c) a methylvinylpolysiloxane having at least three vinyl groups bonded to the silicon atoms in one molecule, (d) a methylhydrogenpolysiloxane having at least three hydrogen atoms bonded directly to the silicon atoms in one molecule, and (e) a catalyst for the addition reaction between the silicon-bonded vinyl groups and the silicon-bonded hydrogen atoms, the total amount of components (a) and (b) being preferably more than 30% by weight of the composition. The compositions, without being diluted with any organic solvents, are applied as a coating on the surfaces of various materials and subsequently heat cured to produce excellent anti-sticking films with superior mechanical properties.

Anti-sticking silicone compositions of non-solvent type

Growing community of inventors

Annaka, Japan

Nobuyuki Hasebe