Preservation of the Appearance of Pre-Printed Graphics on Hot Stretched Film

摘要

The present disclosure is concerned with improving the appearance of graphics printed on a flexible polymer film which is subsequently heated to a forming temperature and then drawn into a mold to form a cavity adapted for the packaging of an item, typically a food item. The improvement is effected by reducing the heat transfer to the portions of the film carrying the graphics thereby reducing the formability of these portions so that they stretch less than the rest of the film which is drawn into the mold. Typically the film is heated by contact with a heated platen. In such cases the reduced heat transfer can be effected by having zones of a cooler temperature which are adapted to be in registry with the portions of the film carrying the graphics or by covering the portions of the heated platen in registry with these graphics with an insulating material such as Teflon tape. The mouth of the cavity can then be closed by sealing to another flexible polymeric film. If the films used are heat shrinkable, the sealed package can be subjected to thermal conditions which cause it to shrink about the packaged item.