Continuous sales letter prodn. - involves punching holes in opaque film, covering holes in transparent film locating letter, folding over film and sealing edges before cutting individual envelopes

摘要

Prodn. of sales letters consisting of the letter (21) printed address (23) and an outer tubular, plastic cover (22) involves; (i) punching windows (24) for the address area (23) at regular intervals along a strip of opaque plastic film (25); (ii) covering the window area (24) with a continuous, transparent film strip (33); (iii) positioning the letters (21) on the film strip (25) such that the address areas (23) correspond with the addresses (23) on the letters (21); (iv) folding over the free half (28) of the opaque film (25) which is slightly wider than the letter (21) height, until the letter (21) is enclosed and two narrow sealing edges (26, 27) of the strip (25) coincide; and are sealed to form a tube (37); (v) bonding the contacting film surfaces (38) between each envelope to seal the envelope (20) ends; and (vi) cutting off individual envelopes. The opaque film (25) may be substd. by a paper strip, pref. having a polypropylene coating along the sealing edges to allow sealing by welding. USE/ADVANTAGE - For continuous prodn. of large-numbers of sales letters. Cheaper prodn. and a uniform, pleasing appearance.