EXtrusion slit die for wide film and sheet - has separate flow channels staggered upper and lower boundaries where channels meet for uniform lateral strength

摘要

Extrusion slit die for e.g. wide flat film and sheet, esp. from thermoplastics polymers, with several adjacent diverging chambers preceding the die lips and fed from a melt channel. The die is split on the longitudinal mid-plane so that each chamber is formed of recesses in the upper and lower halves respectively; the common boundaries between adjacent chambers are staggered with respect to each other. ADVANTAGE - It avoids flowlines and ensures overlapping and fusion where the separate melt streams meet, giving uniform properties, especially of transverse strength. Satisfactory fusion may also be achieved between laterally -adjacent streams of differing or modified polymers.