Shin-etsu Chemical Co., Ltd.

Satoshi Yumoto

Takeshi Fukuda

Noboru Shimamoto

The invention provides a method for the preparation of a cured silicone rubber body by curing at room temperature and yet free from the problems of the low shape-retainability before curing of the conventional room temperature-vulcanizable silicone rubber compositions and the relatively poor mechanical strengths of the cured bodies thereof due to the use of relatively low molecular weight components therein. The method comprises shaping an organopolysiloxane composition comprising an organopolysiloxane of a sufficiently high molecular weight having at least two aliphatically unsaturated hydrocarbon groups, e.g. vinyl groups, per molecule and a platinum catalyst into a desired form and contacting the shaped form with an organohydrogenpolysiloxane in a liquid form so that the latter siloxane diffuses through the shaped body and pertains to the crosslinking reaction with the unsaturated groups in the former siloxane as catalyzed by the platinum catalyst to give a cured silicone rubber body.

Method for the preparation of a shaped article of cured silicone rubber

The present invention provides a unique solution of the difficult problem in the prior art that no efficient peelable release paper is available for temporarily protecting the sticky surface of the adhesive sheet material, e.g. adhesive tapes, adhesive labels, stickers and the like, from inadvertent sticking to an undesired surface when the sticking agent on the adhesive sheet is a silicone-based one. The inventive adhesive sheet material with temporarily protecting covering sheet is formed by use of a sheet of a hydrophilic material such as cellophane impregnated with water in a water content of at least 10% by weight as the temporarily protecting covering sheet. The thus hydrated protecting covering sheet is peelable with a relatively small peeling force without affecting the sticking power of the sticky surface of the adhesive sheet material.

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Annaka, Japan

Satoshi Yumoto