Method for making corrugated molecularly oriented plastic strapping
AssigneeFMC Corporation
InventorHarold A. Haley
Life of this patent
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Abstract
A method in which a band formed of essentially unoriented thermoplastic polymeric material is provided with a transverse cross-section which is of corrugated configuration and is generally uniform in thickness, with at least portions of such band being compressed so as to orient polymer molecules in the transverse direction of the band, afterwhich the band is elongated to orient polymer molecules thereof also and predominantly in the longitudinal direction of the band. The resulting strapping possess a high tensile strength, improved resistance to longitudinal splitting, good longitudinal stiffness, a reduced tendency to shell when wound as a roll, reduced surface abrasion during transit through strapping equipment and provides for high strength heat seals.
Claims15
A method of making a molecularly oriented thermoplastic strapping including the steps of providing successive longitudinal portions of a band formed of essentially unoriented thermoplastic polymeric material with a like transverse cross-section which is of corrugated configuration and is of generally uniform thickness, in which polymer molecules thereof are oriented transversely of such band, and thereafter elongating said band without destroying the corrugated configuration thereof to also orient polymer molecules longitudinally of said band whereby the longitudinal orientation of polymer molecules in the resulting strapping imparts high tensile strength thereto and the transverse orientation of polymer molecules provides the said strapping with good resistance to longitudinal splitting.
Dependencies are inferred from the claim text.