Beschichtungszusammensetzungen für Mastermedien zur hysteresisfreien Aufzeichnung

摘要

A coating composition is provided for master media for anhysteretic transfer of magnetically recorded information to a copy medium which comprises from about 59 to about 69% of a magnetic pigment, from about 2.95 to about 6.90% of an abrasive powder, from 0 to about 5.4% of a colloidal inorganic powder, from about 2.9 to about 4.5% of a wetting agent, from about 0.7 to about 3.1% of a lubricant, from about 14.1 to about 33.6% of a binder, at least 85% of which is a polyurethane and from 0.05 to about 15% of which is a polyisocyanate crosslinking agent. The composition is preferably disposed on a substrate backcoated with a composition containing from about 15 to about 25% of carbon black, from about 15 to about 25% of an inorganic filler, from about 0.5 to about 2% of an abrasive, from about 20 to about 30% of a vinyl copolymeric binder, from about 15 to about 25% of a polyurethane binder, from about 7.5 to about 17.5% of an NCO terminated crosslinking agent, from about 0.9 to about 2% of a lubricant, and from about 0.06 to about 0.6% of a coating aid. Master media for anhysteretic recording containing the coating composition of the invention and an anhysteretic duplicating system are also provided as are processes for preparing the coating compositions and master media and for anhysteretic duplication.