Abstract: The present invention is an addition reaction type polyorganosiloxane composition which can be cured rapidly at room temperature. A cured product of the composition exhibits high elongation, excellent stress relaxation properties and good reliability under conditions of high temperature and high humidity and exhibits excellent reliability in cold/heat cycling. The composition contains: (A1) a straight chain polysiloxane containing alkenyl groups at both terminals; (B1) a straight chain polysiloxane containing SiH groups at both terminals; (B2) a crosslinkable polyorganohydrogensiloxane; one or more types selected from the group consisting of (A2) a straight chain polysiloxane containing an alkenyl group at one terminal and (B3) a straight chain polysiloxane containing a SiH group at one terminal; and (C) a platinum-based catalyst.

Abstract: The present invention is an addition reaction type polyorganosiloxane composition which can be cured rapidly at room temperature. A cured product of the composition exhibits high elongation, excellent stress relaxation properties and good reliability under conditions of high temperature and high humidity and exhibits excellent reliability in cold/heat cycling. The composition contains: (A1) a straight chain polysiloxane containing alkenyl groups at both terminals; (B1) a straight chain polysiloxane containing SiH groups at both terminals; (B2) a crosslinkable polyorganohydrogensiloxane; one or more types selected from the group consisting of (A2) a straight chain polysiloxane containing an alkenyl group at one terminal and (B3) a straight chain polysiloxane containing a SiH group at one terminal; and (C) a platinum-based catalyst.

Abstract: This room-temperature-curable polyorganosiloxane composition contains: (A) 100 parts by mass of polyorganosiloxane consisting of: (A1) 10 to 80 parts by mass of a both ends alkoxysilyl group-terminated polyorganosiloxane and (A2) 90 to 20 parts by mass of a partial hydrolysis condensate (the number of Si atoms is 10 to 200) of a silane compound expressed by a general formula: R4bSi(OR)4-b; (B) 0.1 to 15 parts by mass of a silane compound or a partial hydrolysis condensate thereof (the number of Si atoms is 1 or more and less than 10) as a cross-linking agent; and (C) 0.1 to 15 parts by mass of an organic titanium compound as a curing catalyst. It has low viscosity and good coatability without a solvent, and forms a cured coating film excellent in scratch resistance.