| 摘要 |
PROBLEM TO BE SOLVED: To provide an organosiloxane block copolymer that is used in an LED sealant, does not reduce durability, and has light transmittance of at least 95%.SOLUTION: An organosiloxane block copolymer comprises a diorganosiloxane unit of formula RSiO(I) of 65-90 mol%, further comprises a siloxane unit of average formula R(OR)SiO(II) of 10-35 mol% (0.5≤x≤1.5; 0≤y≤1; Rs independently represent C-hydrocarbyl; Rs independently represent aryl or C-Chydrocarbyl, where at least 50 mol% of Ris aryl; Rs independently represent Ror H), and has light transmittance of at least 95%. |
