Patent ID: 10479910

Abstract:
A primer composition is provided. The primer composition comprises: (A) an organosiloxane block copolymer represented by the average unit formula: (R12SiO2/2)a(R2SiO3/2)b, wherein each R1 and R2 is independently an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, “a” is a number in the range of 0.40 to 0.90, “b” is a number in the range of 0.10 to 0.60, and “a+b”=1.00, and having 0.5 to 35.0 mol % of silicon atom-bonded hydroxyl groups or silicon atom-bonded alkoxy groups, in which resinous siloxane blocks are connected by linear siloxane blocks; (B) a curing catalyst; and (C) an organic solvent. The primer composition improves the adhesion of silicone-cured products to base materials of optical semiconductor elements, package materials, substrates etc., and can suppress peeling or cracking caused by heat cycles.