Re-usable carbon material contg. polyethylene foil dye carrier - coated with physically drying polyurethane adhesion-improving intermediate layer

摘要

A physically drying polyurethane resin, (A), is used as adhesion-improving intermediate layer in a carbon paper or ribbon material contg. a polyethylene foil as dye-carrier and a dye-releasing carbon layer. Prodn. involves (i) coating the polyethylene foil with (A) dissolved in a mxt. of strong alcohol and/or hydrocarbon solvents diluted with 20-40% ketone which is opt. mixed with a hydrocarbon, (ii) evaporating the solvent and (iii) applying the dye-releasing carbon layer. The intermediate layer of (A) can be used equally well on polypropylene, polyester and polyamide foils. Carbon paper or typewriter ribbons can be used more than once.