Coextruded heat sealable laminar thermoplastic films

• US 4,147,827 A
• Filed: 11/04/1977
• Issued: 04/03/1979
• Est. Priority Date: 11/04/1977
• Status: Expired due to Term

• Current Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: Nahmias, A. Michael, Breidt, Peter Jr., Higgins, Thomas W., Weiner, Milton L.
• Primary Examiner(s): Ansher, Harold
• Application Number:
  US05/848,435
• Time in Patent Office: 515 Days
• Field of Search: 428/910, 428/913, 428/213, 428/218, 428/349, 428/354, 428/355, 428/516, 428/523, 428/517, 428/519, 428/521
• US Class Current: 428/218
• CPC Class Codes: B32B 2038/0028 Stretching, elongating
• CPC Class Codes: B32B 2307/31 Heat sealable
• CPC Class Codes: B32B 2307/518 bi-axially
• CPC Class Codes: B32B 2307/558 Impact strength, toughness
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2307/72 Density
• CPC Class Codes: B32B 2309/02 Temperature
• CPC Class Codes: B32B 2553/00 Packaging equipment or accessories not otherwise provided for
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 37/15 with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
• CPC Class Codes: B32B 38/0012 Mechanical treatment, e.g. roughening, deforming, stretching
• CPC Class Codes: B32B 7/04 Interconnection of layers
• CPC Class Codes: Y10S 428/91 Product with molecular orientation
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/24992 Density or compression of components
• CPC Class Codes: Y10T 428/2826 Synthetic resin or polymer
• CPC Class Codes: Y10T 428/2878 including addition polymer from unsaturated monomer
• CPC Class Codes: Y10T 428/31917 Next to polyene polymer
• CPC Class Codes: Y10T 428/31924 : Including polyene monomers
• CPC Class Codes: Y10T 428/31931 : Polyene monomer-containing
• CPC Class Codes: Y10T 428/31938 : Polymer of monoethylenically unsaturated hydrocarbon

Abstract

Laminar thermoplastic films are provided which exhibit improved heat seal strengths as well as heat seal temperature ranges. The laminates comprise a predominantly propylene-based polymer substrate or core, the propylene core layer being coated with continuous skins, the skins being fabricated from ethylene based resin with a density of less than 0.939.

Claims

1. A heat sealable, biaxially oriented, coextruded thermoplastic film laminate comprising a core layer, at least one surface of the core layer having laminated thereto a skin layer, said core layer comprising a member selected from the group consisting of (1) ethylene/propylene copolymers;

(2) blends of ethylene/propylene copolymer with an aliphatic diene copolymer; and

(3) blends of polypropylene homopolymer with an aliphatic diene copolymer, said skin layers comprising an ethylene based polymer having a density of from about 0.910 to about 0.939 and a melt index of from about 0.3 up to about 20.0 and an ethylene content of at least about 80 percent;

said laminate being further characterized wherein said core layer has a relatively higher melting point than said skin layer.

2. A heat sealable biaxially oriented, coextruded thermoplastic film laminate in accordance with claim 1 wherein said skin layer comprises a member selected from the group consisting of polyethylene, ethylene-vinyl acetate copolymer and ethylene-4-methylpentene-1 copolymer.