Organo-modified silicone, mold release agent for mold casting comprising the same, and mold casting method using the same

An organo-modified silicone obtained by an addition reaction of

• (I) a chain silicone represented by the following general formula (1):
• wherein in the formula (1), R1s each independently represent a hydrocarbon group having 1 to 3 carbon atoms, and a and b are numbers satisfying conditions represented by the following formulae (i) to (iii):
• 0≦a≦195 (i)
• 5≦b (ii)
• 10≦a+b≦200 (iii), with
• (II) at least one hydrocarbon selected from the group consisting of monoolefins having 4 to 18 carbon atoms and aromatic hydrocarbons having an alkenyl group and 8 to 12 carbon atoms, and
• (III) a di(meth)acrylic acid ester represented by the following general formula (2):
• wherein in the formula (2), R2 represents any one selected from the group consisting of linear chain alkylene groups having 2 to 16 carbon atoms, branched chain alkylene groups having 2 to 16 carbon atoms, and oxyalkylene groups whose number of repetitions of an oxyalkylene having 2 to 4 carbon atoms is 1 to 6, and R3s each independently represent a hydrogen atom or a methyl group,
• at a molar ratio satisfying a condition represented by the following formula (iv):
• {a number of moles of the (I) chain silicone}:{a number of moles of the (II) hydrocarbon}:{a number of moles of the (III) di(meth)acrylic acid ester}=A:B:C (iv)
• wherein in the formula (iv), A represents a number of moles of the (I) chain silicone determined from a number average molecular weight of the (I) chain silicone, and B and C are numbers satisfying conditions represented by the following formulae (v) and (vi):
• 0.05A≦C≦A (v)
• A×b−2C=B (vi)
• wherein in the formula (vi), b has the same meaning as that of b in the formula (1) in the presence of a hydrosilylation catalyst.