SML Maschinengesellschaft mbH, Austria, has introduced a machine that it says allows the production of high-quality PP film of 100-500 (micro)m in thickness.
The machine uses a technique called Sleeve-Touch Technology. In this process, the vertical melt curtain is cooled down between a seamless steel belt and a chill-roll on a horizontal roll-stack. Low contact pressure on both sides of the film allows the processor to achieve film characteristics that were impossible by means of established production methods, SML claims.
Films produced with the machine display several characteristics:
* high gloss or fully or partly matt surface;
* high transparency and low haze;
* no die lines, as found with cast or blown film;
* low orientation and internal residual stress, especially compared with calendered film;
* good optical properties (no micro-clouds or orange peel effect).
Film produced by the new SML Sleeve-Touch Technology equipment can be either wound or cut in-line into desired sheet sizes, depending on the requirements of subsequent processing methods.
The Sleeve-Touch Technology machine makes a number of principal products:
* folded boxes for consumer products, such as cosmetics;
* stationary products, such as files and folders;
* thermoformed containers and cups for food packaging, also in combination with barrier materials, such as ethylene-vinyl alcohol (EVOH) and polyamide;
* highly transparent lids for re-closable food packaging containers, for instance yoghurt and margarine tubs;
* blister packaging.
SML developed Sleeve-Touch Technology in cooperation with a Japanese partner who has already delivered similar technology on more than 20 production lines in the Far East. SML is now promoting and developing this technology in the European and North American markets for PP film. Future research will be focused on applications with other types of plastic films