Preshrunk textile supports - for offset printing without precoating

摘要

A woven fabric formed from continuous filaments or shrinkable yarns, is first subjected to thermal treatment either free or under tension so that it shrinks and the gaps are filled, and then heated under tension to yield a plane surface to the structure. Due to their uneven surface and coarse structure fabrics for printing usually need a support and a coating to smooth the surface. Fine work without need of support or coating is permitted. Prefd. fibres are of vinyl chloride (co)polymers. Initial thermal treatment may be in boiling water for about 1/2 hr., the fabric being immersed in cold water and gradually brought up to temp. Passage of the fabric over two drums at 105-110 degrees C smooths the faces of the fabric. The thermal treatment under tension is pref. in a tenter with hot air at 120 degrees C for about 40 secs. at 30 m/mn. Offset printing is carried out by attaching one of the faces to a smooth base, passing through the machine without ink under maximum pressure, allowing it to dwell for a number of hours and then printing under min. pressure.