Melt spun polyester nonwoven sheet
AssigneeE. I. Du Pont de Nemours and Company
InventorsVishal Bansal, Michael C. Davis, Edgar N. Rudisill
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Abstract
This invention provides a process for making a nonwoven sheet of substantially continuous melt spun fibers by extruding melt spinnable polymer containing at least 30% by weight low IV poly(ethylene terephthalate), drawing the extruded fiber filaments at a rate of at least 6000 m/min, laying the fiber filaments down on a collection surface, and bonding the fiber filaments together to form a nonwoven sheet. The invention further provides a nonwoven sheet comprised of at least 30% by weight poly(ethylene terephthalate) having an intrinsic viscosity of less than 0.62 dl/g, where the sheet has a basis weight of less than 125 g/m2, and a grab tensile strength of at least 0.7 N/(g/m2).
Claims23
A process for making a nonwoven sheet of substantially continuous multiple component melt spun fibers, comprising the steps of:
- extruding melt spinnable polymer containing at least 30% by weight of a first component of poly(ethylene terephthalate) having an intrinsic viscosity of less than 0.62 dl/g and a second melt spinnable polymer component through a plurality of capillary openings in a spin block to form substantially continuous multiple component fiber filaments;
- drawing said extruded multiple component fiber filaments by feeding the extruded multiple component fiber filaments into a draw jet so as to apply a drawing tension to the multiple component fiber filaments, said draw jet including a fiber entrance, a fiber passage where an air jet pulls the filaments in the direction that the filaments are traveling, and a fiber exit through which the drawn filaments are discharged from the draw jet;
- discharging the drawn multiple component fiber filaments as substantially continuous multiple component fiber filaments through the fiber exit of the draw jet in a downwardly direction at a rate of at least 6000 m/min;
- laying the multiple component fiber filaments discharged from the fiber exit of the draw jet on a collection surface, said multiple component fiber filaments having an average cross sectional area of less than about 90 square microns;
- and
- bonding the multiple component fiber filaments together to form a nonwoven sheet, wherein said nonwoven sheet has a basis weight of less than 125 g/m2, said nonwoven sheet has a machine direction and a cross direction, and said nonwoven sheet has a grab tensile strength in both the machine and cross directions, normalized for basis weight and measured according to ASTM D 5034, of at least 0.7 N/(g/m2).
A nonwoven sheet comprised of at least 75% by weight of melt spun substantially continuous multiple component fibers (A) that are at least 30% by weight poly(ethylene terephthalate) having an intrinsic viscosity of less than 0.62 dl/g, wherein said fibers have an average cross sectional area of less than about 90 square microns, and said nonwoven sheet has a basis weight of less than 125 g/m2, said nonwoven sheet has a machine direction and a cross direction, and said nonwoven sheet has a grab tensile strength in both the machine and cross directions, normalized for basis weight and measured according to ASTM D 5034, of at least 0.7 N/(g/m2).
Dependencies are inferred from the claim text.