Flash-spun sheet material
AssigneeE. I. Du Pont de Nemours and Company
InventorsRobert Anthony Marin, Larry R. Marshall, Barbara K. O'Rourke
Life of this patent
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Abstract
This invention relates to improved plexifilamentary sheet material useful in protective apparel and filtration media, which material is comprised of substantially continuous polyethylene plexifilamentary fiber strands and has a Frazier Permeability, normalized to 1.0 oz/yd2 basis weight, of at least 2 cfm/ft2.
Claims81
A polyethylene plexifilamentary fiber strand produced by a process comprising flash spinning a solution of 12% to 24% by weight polyethylene in spin agent consisting of a mixture of normal pentane and cyclopentane at a spinning temperature from about 205° C. to 220° C. to form said plexifilamentary fiber strand having a surface area of less than 10 m2/g and a crush value of at least 1 mm/g.
A nonwoven unitary fibrous sheet produced by a process comprising flash spinning a solution of 12% to 24% by weight polyethylene in spin agent consisting of a mixture of normal pentane and cyclopentane at a spinning temperature from about 205° C. to 220° C. to form substantially continuous polyethylene plexifilamentary fiber strands having surface areas of less than 10 m2/g and crush values of at least 1 mm/g;
- collecting said plexifilamentary fiber strands to form a sheet;
- and bonding said sheet to form said nonwoven unitary fibrous sheet comprised of substantially continuous polyethylene plexifilamentary fiber strands and having a Frazier Permeability, normalized to 1.0 oz/yd2 basis weight, of at least 2 cfm/ft2.
A nonwoven sheet produced by a process comprising flash spinning a solution of 12% to 24% by weight polyethylene in spin agent consisting of a mixture of normal pentane and cyclopentane at a spinning temperature from about 205° C. to 220° C. to form substantially continuous polyethylene plexifilamentary fiber strands having surface areas of less than 10 m2/g and crush values of at least 1 mm/g;
- collecting said plexifilamentary fiber strands to form a sheet;
- and bonding said sheet to form said nonwoven sheet comprised of substantially continuous polyethylene plexifilamentary fiber strands and having a hydrostatic head of at least 110 cm and a Gurley Hill Porosity of less than 6 seconds.
A flash-spun polyethylene plexifilamentary fiber strand having a surface area of less than 10 m2/g and a crush value of at least 1 mm/g.
A nonwoven sheet comprising substantially continuous, flash-spun polyethylene plexifilamentary fiber strands, the strands having surface areas of less than 10 m2/g and crush values of at least 1 mm/g.
A method of forming a polyethylene plexifilamentary fiber strand comprising:
- providing a solution of 12% to 24%, by weight of the solution, of polyethylene and a spin agent consisting of a mixture of normal pentane and cyclopentane;
- and
- flash spinning the solution at a spinning temperature from about 205° C. to 220° C. to form the polyethylene plexifilamentary fiber strand;
- and
- wherein the polyethylene plexifilamentary fiber strand has a surface area of less than 10 m2/g and a crush value of at least 1 mm/g.
A method of producing a nonwoven unitary fibrous sheet comprising;
- providing a solution of 12% to 24%, by weight of the solution, polyethylene and a spin agent consisting of a mixture of normal pentane and cyclopentane;
- flash spinning the solution at a spinning temperature from about 205° C. to 220° C. to form substantially continuous polyethylene plexifilamentary fiber strands;
- wherein the polyethylene plexifilamentary fiber strand has a surface area of less than 10 m2/g and a crush value of at least 1 mm/g;
- collecting the polyethylene plexifilamentary fiber strands to form a sheet;
- and
- bonding the sheet to form the nonwoven unitary fibrous sheet.
A method for producing a nonwoven sheet comprising:
- providing a solution of 12% to 24%, by weight of the solution, polyethylene and a spin agent consisting of a mixture of normal pentane and cyclopentane;
- flash spinning the solution at a spinning temperature from about 205° C. to 220° C. to form substantially continuous polyethylene plexifilamentary fiber strands;
- collecting the plexifilamentary fiber strands to form a sheet;
- and
- bonding the sheet to form the nonwoven sheet;
- wherein the substantially continuous polyethylene plexifilamentary fiber strands have surface areas of less than 10 m2/g, crush values of at least 1 mm/g, a hydrostatic head of at least 110 cm, and a Gurley Hill Porosity of less than 6 seconds.
A nonwoven sheet comprising substantially continuous, flash-spun polyethylene plexifilamentary fiber strands and having a Frazier Permeability, normalized to 1.0 oz/yd2 basis weight, of at least 2 cfm/ft2.
Dependencies are inferred from the claim text.