Silanol condensation catalyst, heat-curable silicone resin composition for sealing photosemiconductors and sealed photosemiconductor using same

A heat-curable silicone resin composition for sealing optical semiconductors comprising:

• (A) 100 parts by mass of a polysiloxane containing two or more silanol group in the molecule;
• (B) from 0.1 to 2,000 parts by mass of a silane compound containing two or more alkoxy group that are bonded to a silicon atom in the molecule;
• (C) a zirconium metal salt expressed by Formula (I):
• (wherein n is an integer from 1 to 3;
• each R1 is a hydrocarbon group having from 1 to 16 carbons;
• and each R2 is a hydrocarbon group having from 1 to 18 carbons);
• and
• from 0.1 to 5 parts by mass of bis(alkoxysilyl)alkane per the total 100 parts by mass of the polysiloxane and the silane compound.

A sealed optical semiconductor formed by sealing a LED chip by:

• applying a heat-curable silicone resin composition for sealing optical semiconductors to the LED chip, the heat-curable silicone rein composition for sealing optical semiconductors comprising:
• (A) 100 parts by mass of a polysiloxane containing two or more silanol group in the molecule;
• (B) from 0.1 to 2,000 parts by mass of a silane compound containing two or more alkoxy group that are bonded to a silicon atom in the molecule;
• and
• (C) a zirconium metal salt expressed by Formula (I):
• (wherein n is an integer from 1 to 3;
• each R1 is a hydrocarbon group having from 1 to 16 carbons;
• and each R 2 is a hydrocarbon group having from 1 to 18 carbons),
• heating the LED chip, and
• curing the heat-curable silicone resin composition for sealing optical semiconductors.