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US 7,790,641 B2Granted
Bicomponent sheet material having liquid barrier properties
AssigneeFiberweb, Inc.
InventorsJohn Frank Baker, Jr., Gregory W. Farell, Shannon Schoppman
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AssigneeFiberweb, Inc.
InventorsJohn Frank Baker, Jr., Gregory W. Farell, Shannon Schoppman
Estimating the term…
The invention provides a sheet material comprising bicomponent filaments having first and second polymer components that are arranged in substantially distinct zones within the filaments, with the first polymer component formed of a relatively lower melting polymer and the second component formed of a relatively higher melting polymer. The filaments of the nonwoven fabric layer are densely arranged and compacted against one another to form smooth, substantially nonporous opposite outer surfaces, and the nonwoven fabric layer are calendered such that the lower melting sheath polymer is fused to the contacting surface portions of adjacent filaments to impart strength and coherency to the nonwoven fabric layer. The sheet material has excellent breathability and liquid barrier properties and may be useful in house wrap, medical garments, and envelope applications.
A nonwoven sheet material having liquid barrier properties, said sheet material having opposite sides and consisting of a spunbond nonwoven fabric including bicomponent filaments having first and second polymer components that are arranged in substantially distinct zones within the filaments, with the first polymer component formed of a relatively lower melting polyethylene polymer and the second component formed of a relatively higher melting polymer, the filaments of the nonwoven fabric being densely arranged and compacted against one another to form a substantially smooth outer surface on at least one said side of the nonwoven sheet material, and the nonwoven fabric being high pressure calendered at a nip pressure of about 1500 to 3000 pounds per lineal inch and at an elevated temperature such that the lower melting first polymer component of the filaments is fused to the contacting surface portions of adjacent filaments to impart strength and coherency to the nonwoven fabric, and the lower melting polymer component has softened and flowed to form a microporous film that permits moisture vapor to be transmitted through the sheet material while serving as a barrier to the penetration of liquids, and said sheet material having an air permeability, measured in accordance with ASTM test method D-1117, of from 0 to 5 cfm/ft2/min.
A breathable nonwoven sheet material having liquid barrier properties comprising substantially continuous sheath-core filaments that are densely arranged and compacted against one another and thermally calendered at elevated termperature at a nip pressure of about 1500 to 3000 pounds per lineal inch to form a smooth outer surface on at least one side of the sheet material, wherein the sheath component comprises polyethylene or a copolymer thereof and the core component comprises polyester, polypropylene, or copolymers thereof having a higher melting temperature than the sheath-component, and wherein the sheath polymer is fused to the contacting surface portions of adjacent filaments to impart strength and coherency to the nonwoven sheet materials and the sheath polymer has softened and flowed to form a microporous film-like surface that permits moisture vapor to be transmitted through the sheet material while serving as a barrier to the penetration of liquids, and said sheet material having an air permeability, measured in accordance with ASTM test method D-1117, of from 0 to 5 cfm/ft2/min.
Dependencies are inferred from the claim text.