IMPREGNATING INSULATING VARNISH Russian patent published in 2008 - IPC H01B3/30 

FIELD: electric insulating varnishes for impregnating windings of electrical machines and apparatuses.

SUBSTANCE: used in proposed Class F (155 °C) insulating varnish are epoxy-dian resin with epoxy group mass fraction of 16-18% and low-butane melamine-formaldehyde resin, as cross-linking agents, as well as tetrabutoxytitanium and 2-methylimidazole based complex at temperature of 140 °C, as curing catalysts. Varnish solvents are xylene and cyclohexanon. Proposed compounding of varnish implies use of raw materials taken in following proportion, part by mass: hydroxyl-containing oligoester, 37-44; epoxy-dian resin, 17.9-19.0; low-butane melamine-formaldehyde resin, 17.9-19.0; 2-methylimidazole, 0.09-0.1; tetrabutoxytitanium, 0.41-0.43; cyclohexanon, 0.42-0.56; xylene, 14-16.

EFFECT: reduced cost, enhanced availability and relative safety of cross-linking agents, enhanced fraction of nonvolatile materials, viability, and cementing capacity of varnish.

1 cl, 2 tbl, 9 ex