The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 08, 1979
Filed:
Oct. 03, 1977
Thomas E Brady, Sylvania, OH (US);
Nicholas J Curto, Monroe, MI (US);
Owens-Illinois, Inc., Toledo, OH (US);
Abstract
A method is disclosed for enhancing the yield strength and density of polyethylene terephthalate and other similar thermoplastic materials which are susceptible to strain hardening. In the method, the plastic material is thermally conditioned to a temperature within a range conducive to molecular orientation, and then is mechanically conditioned by stretching in a first direction to a length at least about 2.6 to 2.75 times the original length. Thereafter, the plastic material is stretched in a second direction, with strain hardening and strain-induced crystallization increasing drastically substantially immediately upon the initiation of the second stretching operation due to the mechanical conditioning by elongation during the first stretch. The invention is particularly suitable for forming blow molded containers, where a blowable parison or preform is first stretched along its longitudinal axis to the critical length and is then extensively strain hardened while being blown to the configuration of the container.