GB1122925A - Nitrogen-containing polycondensates - Google Patents

Abstract

The invention comprises branched polycondensates which contain (a) residues of compounds containing both 2 and more than 2 functional groups which are amino, hydroxyl and/or carboxyl groups, the residues being joined by ester, amide, imide, benzimidazole and/or benzoxazole group and (b) 2-(benzimidazol-21yl) benzoic acid residues or 2-(benzimidazol-21yl) benzoic acid lactam residues, joined to the remainder of the molecule through their 3, 4, 5 or 6 and 41, 51, 61 or 71 positions, by another such residue or one of the above linking groups. Compounds containing the 2-(benzimidazol-21yl) benzoic acid or acid lactam residue may be derived from (i) an aromatic compound containing 2 mutually ortho carboxyl groups and at least one other functional group and (ii) an aromatic compound having 2 mutually ortho amino-groups and at least one other functional group. This reaction may be at 100-300 DEG C. in a solvent, the reactants being added to the reaction vessel alternately or mixed and added in portions, the portions being of the same or differing reactant ratios. These compounds may be polycondensed with other reactants such as polycarboxylic acids, polyamines, polyhydric alcohols, polyhydric phenols, aminoacids, hydroxyacids, aminoalcohols, and aminophenols at up to 300 DEG C. in an inert gas flow. The polycondensates may be dissolved in organic solvents containing hardening agents, applied to conductors and heated at 150-650 DEG C. to cure them to an insulating coating. In examples, 2-(benzimidazoyl) benzoic acid and acid lactam forming compounds used are trimellitic anhydride, 3,4-diamino benzoic acid and 3,31-diaminobenzidene. Other reactants are a polyester prepared from ethylene glycol, glycerol and terephthalic acid in the presence of zinc acetate, trimellitic anhydride, diamino diphenyl methane, diphenyl terephthalate, a polyester prepared from ethylene glycol, glycerol, terephthalic acid and naphthalene-2,6-dicarboxylic acid in the presence of zinc acetate, 3,4-diamino-benzoic acid and methyl phenyl terephthalate. The products are dissolved in cresol and transesterified with butyl titanate to introduce titanate groups into them. The treated solution is diluted with a mixture of cresol, naphtha, xylene, tetralin and pine-base levelling agent to form a wire lacquer.