Curable silicone composition and cured product thereof

A curable silicone composition comprising:

• (A) an epoxy-functional silicone resin represented by the following average unit formula:
• (R13SiO1/2)a(R12SiO2/2)b(R1SiO3/2)c(SiO4/2)d
• wherein each R1 is the same or different organic group selected from a C1-6 monovalent aliphatic hydrocarbon group, a C6-10 monovalent aromatic hydrocarbon group, and a monovalent epoxy-substituted organic group, provided that at least about 15 mol % of the total R are the C6-10 monovalent aromatic hydrocarbon groups;
• and “a”, “b”, “c”, and “d” are numbers that satisfy the following conditions:
• 0≤a<0.4, 0<b<0.5, 0<c<1, 0≤d≤0.4, 0.1≤b/c≤0.6, and a+b+c+d=1;
• and about 2 to about 30 mol % of the total siloxane units have the monovalent epoxy-substituted organic groups;
• (B) an epoxy-functional silicone represented by the following general formula:
• X1—R22SiO(SiR22O)mSiR22—X1
• wherein each R2 is the same or different organic group selected from a C1-6 monovalent aliphatic hydrocarbon group and a C6-10 monovalent aromatic hydrocarbon group;
• each X1 is the same or different group selected from a monovalent epoxy-substituted organic group and an epoxy-functional siloxy group represented by the following general formula:
• X2—R32SiO(SiR32O)xSiR32—R4—
• wherein each R3 is the same or different C1-6 monovalent aliphatic hydrocarbon group;
• R4 is a C2-6 alkylene group;
• X2 is a monovalent epoxy-substituted organic group;
• and “x” is a number of from about 0 to about 5, and “m” is a number of from about 0 to about 100, in an amount of from about 5 mass % to about 40 mass % of the total mass of components (A), (B), (C) and (D);
• (C) a cationic photoinitiator, in an amount of from about 0.2 mass % to about 2 mass % of the total mass of components (A), (B), (C) and (D);
• and
• (D) a silatrane derivative or a carbasilatrane derivative, wherein each derivative has at least one silicon atom-bonded alkoxy group per molecule, in an amount of from about 0.01 mass % to about 5.0 mass % of the total mass of components (A), (B), (C) and (D).