Organosilicon compound, thermosetting resin composition containing the organosilicon compound, hardening resin and encapsulation material for optical semiconductor

A method for manufacturing a liquid organosilicon compound represented by formula (1) as described below:

• wherein, X is each independently a group represented by formula (I), formula (II) or formula (III) as described below, and when the number of the group represented by formula (I) per one molecule of the liquid organosilicon compound represented by general formula (I) (or the mean number of groups per one molecule of the compound when the compound is a mixture having a different ratio for the group represented by formula (I), the group represented by formula (II), and the group represented by formula (3), is defined as a, the number of the group represented by formula (II) per one molecule thereof is defined as b, and the number of the group represented by formula (III) per one molecule thereof is defined as c, 0≦a≦3.5, 0≦b≦3.5, and 0≦c≦1 are obtained, and also a+b+2c=4 is obtained:
• wherein, R1 is each independently a group selected from alkyl having 1 to 4 carbons, cyclopentyl and cyclohexyl, R2 and R3 are each independently a group selected from alkyl having 1 to 4 carbons, cyclopentyl, cyclohexyl and phenyl, m and n are the number of repetitions of —OSi(R3)2—, and a mean value satisfying 1 to 50,
• the method comprising a process for allowing a hydrosilylation reaction between a compound represented by general formula (2-1) as described below and a compound represented by general formula (2-2) as described below while a Pt catalyst is added, wherein the hydrosilylation reaction and liquefaction is allowed in an amount of twice or more the number of moles of the general formula (2-2) based on the number of the moles of the general formula (2-1), and an amount of Pt catalyst is in a concentration range of 0.001 to 0.08 ppm based on the compound represented by formula (2-1):
• wherein, in the general formulas (2-1) and (2-2), R1, R2, R3 and n are defined in a manner similar to the definitions in general formula (1).