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In‐line annealing—a new approach to the extrusion of high quality rigid vinyl products
Author(s) -
Socha Robert P.
Publication year - 1966
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760060313
Subject(s) - materials science , extrusion , rheology , shrinkage , annealing (glass) , residual stress , composite material , polymer
Most polymers exhibit a very fluid melt rheology during extrusion and can be distorted, drawn down, and cooled without building excessive residual stresses into the product. In contrast, rigid vinyl is usually extruded as a stiff, almost selfsupporting mass. Care must be taken to prevent the formation ot oriented stresses in the product which will be relieved during long periods of exposure resulting in dimensional instability and related loss of physical properties. A newly developed method of in‐line annealing has shown to be an effective means of relieving oriented stresses developed during extrusion. By use of this instrumented technique, rigid vinyl products can be controlled to much tighter shrinkage specifications in a single step process, thereby eliminating post‐annealing treatments.