Patent ID: 8497025

Claim:
A polyimide having a structural unit represented by formula (1), wherein: —(O—X—O)— is a structure of formula (2), shown below, or formula (3), shown below, —(Y—O)— is an arrangement of one kind of structure of formula (4), shown below, or a random arrangement of at least two kinds of structures of the formula (4), each of a and b is an integer of 0 to 100, provided that at least one of a and b is not 0, and Ar represents a tetravalent aromatic group selected from the group consisting of a monocyclic aromatic group, a condensed polycyclic aromatic group and a non-condensed polycyclic aromatic group having a structure in which monocyclic aromatic groups are connected to each other directly or through a connecting group, wherein: R 1 , R 2 , R 3 , R 7 and R 8 are the same or different and represent an alkyl group having 6 or less carbon atoms or a phenyl group, and R 4 , R 5 and R 6 are the same or different and represent a hydrogen atom, an alkyl group having 6 or less carbon atoms or a phenyl group, wherein: R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 are the same or different and represent a hydrogen atom, an alkyl group having 6 or less carbon atoms or a phenyl group, and -A- represents a linear, branched or cyclic bivalent hydrocarbon group having 20 or less carbon atoms, wherein: R 17 and R 18 are the same or different and represent an alkyl group having 6 or less carbon atoms or a phenyl group, and R 19 and R 20 are the same or different and represent a hydrogen atom, an alkyl group having 6 or less carbon atoms or a phenyl group, wherein the polyimide has (i) a dielectric constant measured at 10 GHz at a moisture adsorbed time of less than or equal to 2.80, and (ii) a dielectric loss tangent measured at 10 GHz at a moisture adsorbed time of less than or equal to 0.012.