Organopolysiloxane composition, and half-cured product and cured product produced from same

[0077]A composition was prepared comprising: 3.5 parts by weight of a vinyl-capped branched polysiloxane (A-1) represented by the average composition formula: (Me2ViSiO1 / 2)0.044(Me3SiO1 / 2)0.411(SiO4 / 2)0.545; 89.7 parts by weight of a vinyl-capped linear polysiloxane (A-2) represented by the average composition formula: ViMe2SiO(SiMe2O)322SiMe2Vi; 6.8 parts by weight of a linear polysiloxane (B-1) represented by the average composition formula: HMe2SiO(SiMe2O)10SiMe2H; 5 ppm of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (C-1) in terms of platinum atoms; and 20 ppm of (methylcyclopentadienyl) trimethylplatinum (IV) (D-1) in terms of platinum atoms. The viscosity of the composition was 1,800 mPa·s. After preparing the composition and allowing it to stand for 10 minutes to reach a viscosity of 3,200 mPa·s, the composition was exposed via an ozone cut filter to a 2 W high-pressure mercury lamp at a 365-nm UV exposure level of 5,000 mJ / cm2. The viscosity measured im

[0078]A composition was prepared comprising: 3.5 parts by weight of A-1; 6.5 parts by weight of A-2; 82.4 parts by weight of a vinyl-capped linear polysiloxane (A-3) represented by the average composition formula: ViMe2SiO(SiMe2O)535SiMe2Vi; 4.6 parts by weight of B-1; 10 ppm of C-1 in terms of platinum atoms; and 20 ppm of D-1 in terms of platinum atoms. The viscosity of the composition was 8,200 mPa·s. After preparing the composition and allowing it to stand for 10 minutes to reach a viscosity of 14,000 mPa·s, the composition was exposed via an ozone cut filter to a 2 W high-pressure mercury lamp at a 365-nm UV exposure level of 2,500 mJ / cm2. The viscosity measured immediately thereafter was above 50,000 mPa·s, but the composition remained fluid. It became a non-fluid gel after 10 more minutes of UV exposure. When the hardness of the cured product was measured by penetration every 10 minutes, the hardness stabilized at a penetration of 35 after one hour of UV exposure indicating th

[0079]A composition was prepared comprising: 55.7 parts by weight of a vinyl-capped branched polysiloxane (A-4) represented by the average composition formula: (Me2ViSiO1 / 2)0.1(Me3SiO1 / 2)0.4(SiO4 / 2)0.5; 13.3 parts by weight of a branched polysiloxane (E-1) represented by the average composition formula: (Me3SiO1 / 2)0.44(SiO4 / 2)0.56; 1.7 parts by weight of a vinyl-capped linear polysiloxane (A-3) represented by the average composition formula: ViMe2SiO(SiMe2O)160SiMe2Vi; 24.6 parts by weight of a linear polysiloxane (B-2) represented by the average composition formula: HMe2SiO(SiMe2O)400SiMe2H; 4.7 parts by weight of a linear polysiloxane (B-3) represented by the average composition formula: Me3SiO(SiMe2O)30(SiMeHO)30SiMe3; 0.2 ppm of C-1 in terms of platinum atoms; and 5 ppm of D-1 in terms of platinum atoms. The viscosity of the composition was 3,500 mPa·s. The composition was heated for 30 minutes at 90° C. A thermoplastic material was obtained that was not fluid at 25° C. b