Polyamide acid, thermoplastic polyimide, resin film, metal-clad laminate and circuit board

A thermoplastic polyimide that includes a diamine residue derived from a diamine component and a tetracarboxylic acid residue derived from an acid anhydride component,

• wherein the thermoplastic polyimide includes a diamine residue derived from at least one selected from among diamine compounds represented by the following general formulae (1) to (7) within the range of 40 to 97 parts by mole in total and a diamine residue of at least one selected from among diamine compounds represented by the following general formula (8) within the range of 5 to 40 parts by mole in total with respect to 100 parts by mole of all diamine residues, and
• wherein the thermoplastic polyimide includes a tetracarboxylic acid residue derived from biphenyl tetracarboxylic acid dianhydride within the range of 40 to 100 parts by mole and a tetracarboxylic acid residue derived from pyromellitic acid dianhydride within the range of 0 to 60 parts by mole with respect to 100 parts by mole of all tetracarboxylic acid residues.
• in formulae (1) to (7), R1 independently represents a monovalent hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, linking groups A independently represent a divalent group selected from among —O—, —S—, —CO—, —SO—, —SO2—, —COO—, —CH2—, —C(CH3)2—, —NH— and —CONH—, and n1 independently represents an integer of 0 to 4, and here, in the case of formula (6), the linking group A is a divalent group selected from among —O—, —SO2—, or —CO—, parts in formula (3) that are the same as those in formula (2) are excluded, and parts in formula (5) that are the same as those in formula (4) are excluded
• in formula (8), a linking group X represents a single bond or —CONH—, each Y independently represents hydrogen, a monovalent hydrocarbon group having 1 to 3 carbon atoms or an alkoxy group, n represents an integer of 1 or 2, and p and q independently represent an integer of 0 to 4.