| 摘要 |
A heat-hardenable condensation product is obtained from an aromatic diprimary amine, an aromatic tricarboxylic acid anhydride and excess of a C2- 6 glycol, the unreacted glycol being distilled off. Diamines specified include bis(aminophenyl) methane, bis(aminophenyl)-propane and bis(aminophenyl) ether. 0.9 to 1.1 moles may be used per mole of tricarboxylic acid anhydride. The aromatic diamine may be supplemented with a minor amount of an aliphatic or cycloaliphatic diamine. Tricarboxylic acids specified include trimellitic anhydride. It may be reacted with the C2- 6 glycol before reaction with the diamine. Glycols specified include ethylene glycol and propane-1,3-diol. The glycol may be supplemented with up to 30% of a C3- 8 triol, e.g. glycerol. The condensation may occur in the presence of an esterification catalyst, e.g. Sb2O3 or stannic oxide. The product may be dissolved in cresol, optionally diluted with a hydrocarbon, and the resulting solution applied to an electrical conductor and hardened.ALSO:An electrically insulating lacquer comprises a cresol solution of a thermosetting condensation product of an aromatic tricarboxylic acid mono-anhydride, excess of a glycol having 2 to 6 carbon atoms and an aromatic diprimary amine, the unreacted glycol being subsequently distilled off. Part of the glycol may be replaced by a C3-8 triol. The cresol solution may be further diluted with a hydrocarbon, e.g. toluene, xylene or solvent naphtha. The laquer may be applied by flame-spraying, fluidized bed coating or normal wire-coating techniques. In typical Example 1 a condensation product prepared from trimellitic anhydride, ethylene glycol and bis(4-aminophenyl) methane in the presence of Sb2O3 is dissolved in cresol and xylene and xylene and applied to Cu wire in a horizontal wire-coating furnace. In other examples additional reactants were propane-1,3-diol, glycerol, bis(4-aminophenyl) ether, bis (4-aminophenyl) propane and stannic oxide. |
