Abstract: A silicon-based curable composition providing improved transparency, mechanical strength and resistance against heat and photo-degradation comprises at least one organopolysiloxane represented by the composition formula (1): (R13SiO1/2)a(R12SiO2/2)b(R1R2SiO2/2)c(R1SiO3/2)d(R2SiO3/2)e(R12R2SiO1/2)f??(1), wherein each R2 independently represents a methacryloxyalkyl group having 5 to 20 carbon atoms and a?0, b?0, c?0, d?0, e?0, f?0, c+e>0, and a+b+c+d+e+f=1; and at least one curing catalyst. The product is ideal for encapsulation of LED (light emitting device) elements.

Abstract: The present invention relates to a liquid hydrosilicone resin and a preparation process thereof. The average composition of the liquid hydrosilicone resin is represented by the following formula: (R1R2R3SiO1/2)M.(R4R5SiO2/2)D. (R6SiO3/2)T.(SiO4/2)Q wherein R1 to R6 are identical or different radicals independently selected from the group consisting of organic groups and a hydrogen atom, with the proviso that at least one of R1to R6 is a hydrogen atom bonded directly to a silicon atom. The liquid hydrosilicone resin is obtained by dispersing a hydrosilicone oil, a hydroxyl silicone resin and a dehydrogenation catalyst in a solvent to form a dispersion, allowing the dispersion to react, and then removing the solvent and the catalyst.