FUNDAMENTALS OF THE TENTER FRAME PROCESS FOR BIAXIALLY ORIENTED FILM MANUFACTURING AS APPLIED TO POLYPROPYLENE POLYESTER AND HIGH DENSITY POLYETHYLENE

摘要

Biaxially oriented films of polypropylene (PP), polyester (PET) and high density polyethylene (HDPE) can be made in several different processes. The tenter process will first be shown in overview to describe the function of each of the primary manufacturing steps ( coextrusion, casting, machine direction stretching, transverse direction stretching, surface treatment and winding ). Next the primary stretching steps and equipment configurations will be defined and characterized in terms of process and material variables and the film properties produced. From a processing focus, the primary process steps may be considered and evaluated as some form of rheometer, either for melt or solid , and these ideas will be introduced and evaluated as a means of understanding the process / film property interactions.