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. 04, 2003
Filed:
Dec. 03, 1999
Aiko Hanyu, Houston, TX (US);
Ben Wayne Hicks, Shoreacres, TX (US);
Fina Technology, Inc., Houston, TX (US);
Abstract
A multilayer polyolefin film of the type suitable for packaging application in which heat seals are formed, and in its preparation the multilayer film comprises a flexible substrate layer formed of a crystalline thermoplastic polymer having an interface surface. A heat-sealable surface layer is bonded to the interface surface of the substrate layer and is formed of a syndiotactic propylene polymer effective to produce a heat seal with itself at a sealing temperature of less than 110° C. The surface layer has a thickness which is less than the thickness of the substrate layer. The heat-seal layer can be formed of syndiotactic polypropylene polymerized in the presence of a syndiospecific metallocene catalyst and having a melt flow index of less than 2 grams/10 minutes. The multilayer film can take the form of a a biaxially-oriented film. In the production of the multilayer film incorporating a substrate layer and a heat-sealable surface layer, a crystalline thermoplastic polymer is extruded and formed into a substrate layer film. A second polymer comprising a syndiotactic propylene polymer which is effective to form a heat-sealable surface layer is extruded to form a surface layer that is bonded to the interface of the substrate layer at a temperature within the range of 150-260° C.