Unschmelzbares Harz und Verfahren zu seiner Herstellung

摘要

A solid polyamide of molecular weight in excess of 2,500 containing repeating units of one or both of the structures where R is a divalent aromatic group, said polymer being soluble in organic polar solvents and being convertible by heating to a product which is flexible in film form, is insoluble in organic polar solvents and has a high thermal stability is made by reacting an aromatic primary diamine with a trimellitic acid derivative of the formula where Hal is a halogen atom and R1 and R2 are halogen atoms or one of R1 and R2 is a halogen atom and the other is an ester group in the presence of an organic polar solvent at a temperature not exceeding 70 DEG C. Many suitable diamines are specified, e.g. p:p1-methylene-bis(aniline) and p:p1-oxybis(aniline).ALSO:Articles, e.g. wires are coated by applying thereto a solution of a reaction product of a primary aromatic diamine and a trimetallitic acid derivative of the formul and heating to cure (see Division C3). In Example 9, copper panels are coated with solutions in N:N-dimethylformamide of a reaction product of the 4-acid chloride of trimellitic acid and p:p-oxybis (aniline) and baked.