Elongation for flash spun products
AssigneeE. I. Du Pont de Nemours and Company
InventorLarry Ray Marshall
Life of this patent
Estimating the term…
Abstract
This invention relates to improved elongation properties for flash-spun plexifilamentary film-fibrils. The technique for obtaining the improved properties is to increase the length to diameter ratio of the spin orifice and to reduce the ratio of polymer in the spin solution.
Claims25
A flash spun polymeric sheet material having an opacity of greater than 85%, a basis weight greater than 30 g/m.sup.2 but less than 100 g/m.sup.2, and an average break elongation of greater than about 30%.
A flash spun polymeric envelope material having an opacity greater than 85%, a basis weight greater than 30 g/m.sup.2 but less than 100 g/m.sup.2, a Spencer puncture greater than 20 in-lb/in.sup.2 and an average break elongation of greater than about 35%.
In a process for flash spinning polymer and forming fabric therefrom, the improvement comprising spinning a polymer solution through a spin orifice having length to diameter ratio of at least 2.0 and an inline mixer in a letdown chamber upstream of the spinning orifice.
In a process for flash spinning polymer and forming sheet material therefrom, the improvement comprising mixing the polymer in a pentane spin agent at a ratio of less than about 16% polymer, and emitting the polymer solution through a spin orifice at a temperature of at least about 180.degree. C., wherein the spin orifice has a length to diameter ratio of at least 2.0.
Dependencies are inferred from the claim text.