Epoxy compound, epoxy resin, curable composition, cured product thereof, semiconductor sealing material, and printed circuit board

A printed circuit board which is obtained by impregnating a reinforcement basic material with a resin composition varnished by blending a curable composition with an organic solvent, and superposing a copper foil on the resulting material, followed by heat-pressing;

• wherein the curable composition comprises, as essential components:
• an epoxy compound and a curing agent;
• wherein the epoxy compound has a molecular structure represented by the following Formula (I):
• wherein G represents a glycidyl group, and X represents a structural site represented by the following Structural Formula (x1) or (x2);
• wherein, in Formula (x1) or (x2), R1 and R2 each independently represent any of an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, 1 represents an integer of 0 to 3, n represents an integer of 0 to 4, when 1 or n represents 2 or greater, a plurality of R1's or R2's may be the same as or different from each other, k represents an integer of 1 to 3, m represents 1 or 2, Ar represents a structural site represented by the following Structural Formula (Ar1) or (Ar2), and when k or m represents 2 or greater, a plurality of Ar's may be the same as or different from each other;
• wherein, in Formula (Ar1) or (Ar2), G represents a glycidyl group, p and r each independently represent 1 or 2, R3 and R4 each independently represent any of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group, R4 in Formula (Ar2) may be bonded to any one of two aromatic nuclei, q represents an integer of 0 to 4, s represents an integer of 0 to 6, and when q or s represents 2 or greater, a plurality of R3's or R4's may be the same as or different from each other.

An epoxy resin comprising a mixture of dinuclear, trinuclear and tetranuclear epoxy compounds, wherein the dinuclear, trinuclear and tetranuclear epoxy compounds independently each independently have a molecular structure represented by the following Formula (I):

• wherein G represents a glycidyl group, and X represents a structural site represented by the following Structural Formula (x1) or (x2);
• wherein, in Formula (x1) or (x2), R1 and R2 each independently represent any of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group, 1 represents an integer of 0 to 3, n represents an integer of 0 to 4, when 1 or n represents 2 or greater, a plurality of R1's or R2's may be the same as or different from each other, k represents an integer of 1 to 3, m represents 1 or 2, Ar represents a structural site represented by the following Structural Formula (Ar1) or (Ar2), and when k or m represents 2 or greater, a plurality of Ar's may be the same as or different from each other;
• wherein, in Formula (Ar1) or (Ar2), G represents a glycidyl group, p and r each independently represent 1 or 2, R3 and R4 each independently represent any of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group, or an aralkyl group, R4 in Formula (Ar2) may be bonded to any one of two aromatic nuclei, q represents an integer of 0 to 4, s represents an integer of 0 to 6, and when q or s represents 2 or greater, a plurality of R3's or R4's may be the same as or different from each other;
• and wherein:
• the content ratio of the dinuclear compound in the epoxy resin is in the range of 2% to 50% in terms of the area ratio in GPC measurement,
• the content ratio of the trinuclear compound in the epoxy resin is in the range of 10% to 95% in terms of the area ratio in GPC measurement,
• and the content ratio of the tetranuclear compound in the epoxy resin is in the range of 0.5% to 20% in terms of the area ratio in the GPC measurement.