Plastic Envelopes and their Problems for the Postal Service

Envelopes manufactured from plastic films offer many advantages to mailers in terms of security, marketability and most importantly a potential to reduce enveloping costs when compared to traditional paper envelopes. The British Post Office currently prohibits plastic envelopes which are of a size and class that would normally be machine coded and sorted because the physical properties of typical plastics give rise to mechanical transport and code mark printing problems.

This paper describes a research programme to allow the introduction of plastic envelopes. Important aspects of the research include the development of an automatic plastic/paper discriminator and the quantification of the physical properties of an envelope suitable for current code-sort equipment. Modifications to existing equipment to suit common plastic films are discussed together with the development of new plastic films which are both acceptable to the British Post Office for mechanized sorting and acceptable to mailers in terms of cost and other qualities.