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:
Nov. 13, 1979
Filed:
Dec. 09, 1977
Peter Hoj, Espergarde, DK;
Tetra Pak Developpement SA, Lausanne, CH;
Abstract
A web of thermoplastic material and a method and apparatus for manufacture of the web are disclosed with the web having a repeating pattern of alternately thick and thin portions. A molten thermoplastic material is extruded through a duct between a first rotatable driven roll and a circular-cylindrical seat. The first driven roll includes a surface having a pattern of recessed portions. The web is transferred from the first driven roll to a second driven roll having a smooth surface. The temperatures of the first and second rolls may be selectively maintained. The thermoplastic material may be extruded through a plurality of ducts leading to the surface of the first driven roll. Transfer of the web from the first roll to the second may be encouraged by means of a vacuum. Furthermore, complete filling of the recesses of the first driven roll by the thermoplastic material may be encouraged by the use of a vacuum.