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. 26, 1998
Filed:
Apr. 24, 1996
Daniel Cykana, Sheboygan, WI (US);
Steven F Schick, Sheboygan, WI (US);
Bemis Manufacturing Company, Sheboygan Falls, WI (US);
Abstract
A method of extruding a homogeneous plastic rod substantially free of shrink voids, the method having the steps of: extruding a rod central portion of plastic material having a glass transition point and a Vicat softening point below the glass transition point, the rod central portion having a center core and an outer skin; cooling the rod central portion while maintaining the outer skin above the Vicat softening point until the center core is cooled to approximately the Vicat softening point; using an extruder to extrude around the rod central portion a sheath of the same plastic material, the sheath having an outer skin and inner and outer portions, such that the rod central portion acts as a heat sink for the inner portion of the sheath, and such that, at the extruder, the plastic material forming the outer skin of the rod central portion is melted upon contact with the plastic material forming the sheath and the plastic material of the rod central portion and the plastic material of the sheath form the homogeneous rod, and such that the plastic material forming the center core of the rod central portion remains at a temperature below the glass transition point; and cooling the sheath while maintaining the outer skin of the sheath above said Vicat softening point until the inner portion is cooled to approximately the Vicat softening point.