The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 07, 1989
Filed:
Apr. 08, 1988
Yoshinori Hida, Gunma, JP;
Shohei Kozakai, Gunma, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
Whereas the mechanism for the crosslink formation in the curable organopolysiloxane composition of the invention is the ultraviolet-induced addition reaction between alkenyl, e.g., vinyl, groups in a diorganopolysiloxane and mercaptoalkyl groups in another organopolysiloxane as in conventional compositions, the mercaptoalkyl-containing organopolysiloxane used in the invention is, differently from those in conventional compositions, an organopolysiloxane of a three-dimensionally branched molecular structure as composed of the siloxane units of the formulas R.sup.1.sub.3 SiO.sub.0.5, R.sup.1.sub.a (HSR.sup.2)SiO.sub.(3-a)/2 and SiO.sub.2, in which R.sup.1 is, for example, a methyl or phenyl group, R.sup.2 is, for example, --CH.sub.2 CH.sub.2 CH.sub.2 -- and a is zero, 1 or 2, in a specified proportion. In addition, the vinyl group-containing siloxane units in the vinyl-containing diorganopolysiloxane are localized in the molecular structure forming two blocks each bonded to one of the terminal silicon atoms. The inventive composition is advantageous in respect of the greatly improved mechanical strengths of the cured silicone rubber obtained by irradiating the composition with ultraviolet light.