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. 16, 1995
Filed:
Nov. 01, 1993
Du Pont Canada Inc., Mississauga, CA;
Abstract
The process of this invention for making strong, discontinuous fibers from a polyolefin includes feeding a solution of polyolefin dissolved in an organic solvent at a pressure that is at least autogenous pressure to a spinneret. Plexifilamentary film-fibril strands are formed by flash spinning, by passing said solution through the exit of the spinneret and into a tunnel at a lower pressure and temperature than the solution, the temperature being greater than the boiling point of the organic solvent. At or subsequent to the exit from the spinneret but inside the tunnel, the strands and solvent are contacted in the tunnel with an inert fluid that has a liquid and a vapor phase, the amount of inert fluid being such that the ratio of the total volumetric flow rate of solvent vapor plus inert fluid vapor to the mass flow rate of the polymer is greater than 4.5 m.sup.3 /kg in the tunnel. The temperature of the inert fluid in the tunnel is 2.degree.-40.degree. C. lower than the melting point of the polymer. Strong discontinuous fibers are recovered. The fibers, especially in the form of a pulp, may be used as part of thermally bonded blends with cellulose, as a filler and in the form of sheet.