Curable composition, urethane resin, and heat dissipation member

A curable composition comprising:

• a polyol (A);
• a polyisocyanate (B);
• at least one dispersant (C) for inorganic fillers selected from the group consisting of a phosphate ester (C1), a C12-C24 fatty acid (C2), a sucrose fatty acid ester (C3), a sorbitan fatty acid ester (C4), and a glycerol fatty acid ester (C5);
• and
• an inorganic filler (D),
• the curable composition satisfying the following requirements (1) to (3) that
• (1) the polyol (A) contains a polyalkylene glycol (A1) having a chemical formula weight or number average molecular weight of 1000 or less in an amount of 50% by weight or more based on the weight of the polyol (A);
• (2) the inorganic filler (D) is contained in an amount of 70 to 97% by weight based on the weight of the curable composition;
• and
• (3) the total weight of the dispersant (C) for inorganic fillers is 1 to 5 parts by weight per 100 parts by weight of the inorganic filler (D),
• the phosphate ester (C1) being represented by the following formula (1):
• wherein R1 is a hydrogen atom, a C2-C18 alkyl group, or a C2-C18 alkenyl group;
• A1O is a C2-C3 alkyleneoxy group;
• n1 is an integer of 3 to 15;
• and R2 is a hydrogen atom or —(A2O)n2R3, where R3 is a C2-C18 alkyl group or a C2-C18 alkenyl group;
• A2O is a C2-C3 alkyleneoxy group;
• and n2 is an integer of 3 to 15.