Improvements in or relating to surface coating compositions containing epoxy resins

Abstract

Abstract A coating composition is a solution of an epoxy resin with a masked tri-isocyanate or masked tri-isothiocyanate. Copper or aluminium wire may be coated with such compositions followed by stoving at 150 DEG C. or above to release the isocyanate or isothiocyanate for curing the epoxy resin. Other resins, e.g. rosin, amino-formaldehyde or phenol-formaldehyde resins or polyesters may be added to the compositions. Suitable masking agents for the iso- or isothiocyanate are phenols, e.g. m-cresol, mercaptans, amines, hydrazines, malonic ester, acetoacetic ester or butanol. The masking agent may also be a solvent for the epoxy resin. In a typical example a resinous tri-isocyanate obtained from 3 mols. of toluene di-isocyanate with 1 mol. of trimethylol propane is dissolved in mixed ethyl and butyl acetates and mixed with a solution in the same solvents of isobutyl alcohol and a resin sold under the Registered Trade Mark of "Epikote". In other examples m-cresol replaces the iso-butyl alcohol, xylol and n-butanol are added as solvents, the m-cresol is reacted with the triisocyanate before admixture with the epoxy resin solution, rosin is added to the composition, and "Desmodur AP" (Registered Trade Mark) is used as a ready masked tri-isocyanate. Specification 747,607 is referred to.

Inventors

• 👤 Charles Rossall Pye
• 👤 James William Thom

Bibliographic Details