SLIT FILM/MONOFILAMENT EXTRUSION.

Following a few lean years for processors (and machine builders), the slit-film and monofilament areas of extrusion should bounce back at about a 10%/yr growth rate between 1978 and '80 . This paper gives a look at the equipment available to do the job. One pronounced trend these days: buying systems rather than components. Machine builders generally offer 'standard lines', but this term is not terribly meaningful as all equipment suppliers will pretty much custom-build lines to suit customers' speciic needs. To accomplish uniformity of product in slit-film and monofilament work, there are two schools of thought to heating the extruded film or filament, some promoting the use of ovens, others heated rolls. The toughest problem in monofilament work is the take-up of each individual strand after it is extruded and preventing these strands from contacting one another, at least until after quenching. In polyester and nylon monofilament processing, orientation is generally done in steps (a two-stage draw) for better control and a higher quality product that can be accomplished in a single-station draw. Die design considerations are included in this report.