| 摘要 |
PURPOSE: To prevent film dusts from generating due to abrasion and scratching of a film passing on a surface of a vacuum drum during the process of film adhesion by forming an envelope window with a specified film including anti- flecking agent. CONSTITUTION: A film for an envelope with a non-dusting window is preferably comprised of polystyrene and wax of more than one type as an anti-flecking agent of about 0.1-5.0 wt.% and generally comprises an enough quantity of overcasting agent for overcasting the film. The wax concentration which is higher than 5 wt.% in the film is of solubility and non-solubility between polystyrene and wax which results in making the film to be white and discolored. Preferable examples of the wax include saturated fat series with carbon length of about C10 -C35 and acid, acid salt, ester or amide derivatives or the like of wax quality in alkyl aromatic hydrocarbon. |
