Stephen Walter Cook

US Patent:

40426610, Aug 16, 1977

Filed:

Jan 23, 1976

Appl. No.:

5/651983

Inventors:

Stephen Olney Cook - Mill Valley CA

Assignee:

Crown Zellerbach Corporation - San Francisco CA

International Classification:

B29F 310

US Classification:

264173

Abstract:

Tubular multilaminate film having four or more layers can be made by A. combining two or more streams of dissimilar resins to form a first stream of parallel layers of the resins and feeding the stream into a first annular space wherein the stream divides into two substreams which flow laterally in opposite directions about the axis of the space and then join to form a first annular stream in which the layers are coaxial, B. combining two or more other streams of resins to form a second stream of parallel resin layers and feeding the stream into a second annular space which is concentric with the first annular space and wherein the second stream divides into two substreams which flow laterally in opposite directions about the axis of the space and then join to form a second annular stream in which the layers are coaxial, and C. combining the first and second annular streams to form a composite annular stream, and D. expressing the composite annular stream through an annular orifice to form the tubular multilaminate film.

US Patent:

41884418, Feb 12, 1980

Filed:

Feb 17, 1976

Appl. No.:

5/658549

Inventors:

Stephen O. Cook - Mill Valley CA

Assignee:

Crown Zellerbach Corporation - San Francisco CA

International Classification:

B32B 2708
B32B 2732

US Classification:

428216

Abstract:

Flexible packaging films of high density polyethylene capable of forming easily openable heatseals can be made by coextruding a layer of the high density polyethylene adjacent to a layer of a blend of an ionomer and a copolymer of ethylene and vinyl acetate or an ester of acrylic and or methacrylic acid. Packages made from the films by forming a blend-to-blend heatseal can be opened by a force between one and five pounds per inch width.