W. R. Grace & Co., Cryovac Div.

W. R. Grace Co.

Julian H Schoenberg

Walter B Mueller

Henry G Schirmer

Alan S Weinberg

A five layered thermoplastic film may be utilized to form storm windows or packaging material. A preferred embodiment of the film comprises a core layer consisting essentially of either (a) a copolymer of ethylene and vinyl acetate or (b) a three component blend of (a) a linear low density polyethylene, (b) a linear medium density polyethylene and (c) an ethylene vinyl acetate copolymer. The preferred embodiment also comprises two intermediate layers each consisting essentially of a linear low density polyethylene, and two surface layers each consisting essentially of either a four component blend of (1) a linear low density polyethylene, (2) a linear medium density polyethylene, (3) a copolymer of ethylene and vinyl acetate and (4) one or more light stabilizers, or a three component blend in which light stabilizers are not present.

Multi-layer polyolefin shrink film

The present invention comprises an improvement upon the blown bubble process for forming thin heat sealable films from an extruded tubular structure. The utilization of a spray nozzle, internal to the extruded tubular structure, to provide a thin inner coating of a liquid polyorganosiloxane greatly reduces the internal film welding of extruded tubular polyolefin materials which internally weld at their processing temperature. Additionally, reduction of the internal welding allows films of reduced thickness to be manufactured.

Blown bubble process for producing oriented thin films

A three layered thermoplastic film having a desired combination of physical characteristics is disclosed. The film may be utilized to form storm windows. A preferred embodiment of the film comprises a core layer consisting essentially of a linear low density polyethylene and two surface layers comprising a four component blend of (1) a linear low density polyethylene, (2) a linear medium density polyethylene (3) a copolymer of ethylene and vinyl acetate and (4) one or more light stabilizers.

Storm window film

A three layered heat shrinkable, heat sealable thermoplastic packaging film having a desired combination of physical characteristics is disclosed. The film may be utilized to package a wide variety of items. A preferred embodiment of the film comprises a core layer consisting essentially of a linear low density polyethylene and two surface layers comprising a three component blend of (1) a linear low density polyethylene, (2) a linear medium density polyethylene and (3) a copolymer of ethylene and vinyl acetate.

Oriented heat-sealable multilayer packaging film

A five layered thermoplastic film having a desired combination of physical characteristics is disclosed. The film may be utilized to form storm windows. A preferred palindromic embodiment of the film comprises a core layer consisting essentially of either (a) a copolymer of ethylene and vinyl acetate or (b) a three component blend of (a) a linear low density polyethylene, (b) a linear medium density polyethylene and (c) an ethylene vinyl acetate copolymer. The preferred embodiment also comprises two intermediate layers each consisting essentially of a linear low density polyethylene and two surface layers each consisting essentially of a four component blend of (1) a linear low density polyethylene, (2) a linear medium density polyethylene, (3) a copolymer of ethylene and vinyl acetate and (4) one or more light stabilizers. Appropriate slip, antiblock and antioxidant agents may also be present.

Storm window film comprising at least five layers

The multi-layer polyester/polyolefin shrink film of this invention provides a combination of shrink tension, hot seal strength, sealability, and shrink temperature range heretofore unobtainable in an oriented, monolayer polyolefin material. The preferred film has five layers in which the middle layer comprises a polyester or copolyester, two inner layers adjacent the middle layer comprise ethylene-vinyl actate copolymer, and the skin or outer layers comprise an ethylene-propylene copolymer.

Multi-layer polyester/polyolefin shrink film

The multi-layer polyester/polyolefin shrink film of this invention provides a combination of shrink tension, hot seal strength, sealability, and shrink temperature range heretofore unobtainable in an oriented, monolayer polyolefin material. The preferred film has five layers in which the middle layer comprises a polyester or copolyester, two inner layers adjacent the middle layer comprise ethylene-vinyl acetate copolymer, and the skin or outer layers comprises an ethylene-propylene copolymer.

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Greenville, SC, United States of America

Julian H Schoenberg