OPENING OF ENVELOPE WITH DARKENED EDGES

摘要

OPENING OF ENVELOPE WITH DARKENED EDGES A process is provided for the opening of envelopes made of cellulosic paper by the action of a chemical degradation agent in the presence of radiant heat in which the radiant heat is generated from a source maintained at a temperature high enough to produce a substantial amount of radiation having a wave length of 2 microns or less and by applying to the edges to be opened a darkening material capable of absorbing a substantial portion of the incident radiant energy.