| abstract |
Solns. of polyimide-forming materials comprises diamines and tetracarboxylic acid diesters (TCDE). At least 2 mol.% of the ester gps. in the TCDE are derived from alcohols of formula HO-Z-O-X (I) or HO-Z-X (II) is excluded when diamines having basicity constant 10 power (minus 11) or less are used. In formulae, Z is 1-15C aliphatic gp. opt. interrupted by 1-4 ether -O-gps. and X is 5-20C aromatic gp. opt. contg. N, O, S as heteroatoms in aromatic ring systems. (I) is pref. e.g. monophenoxyethylene glycol or monophenoxypropylene glycol, etc.. (II) is pref. e.g. benzyl alcohol or 1-hydroxy-2-phenyl-ethane or-propane, etc.. The solvent is suitably a highly polar solvent such as N-Me pyrrolidone (NMP), formamide, DMF, di-Me-ethylene diurea, DMSO, butyrolactone, glycols or glycol-ethers or -esters. USE/ADVANTAGE - The solns. are used for prodn. of coatings (claimed), e.g. on metals, glass or Si for use in microelectronic switches, etc., They wave solids content of 30-60 wt.% (cf 12-20 wt.% for prior-at solns.) and give smooth, bubble-free coati |