Cold sealable cohesive polymer coated polyolefin substrate

• US 5,486,426 A
• Filed: 11/28/1994
• Issued: 01/23/1996
• Est. Priority Date: 10/04/1993
• Status: Expired due to Term

• Current Assignee: Jindal FIlms Americas LLC (Jindal Films India Ltd.)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: McGee, Dennis E., Touhsaent, Robert E.
• Primary Examiner(s): Yoon, Tae H.
• Application Number:
  US08/345,085
• Time in Patent Office: 421 Days
• Field of Search: 428/343, 428/354, 428/355, 428/414, 428/502, 428/523, 428/516
• US Class Current: 428/516
• CPC Class Codes: C08F 220/12 of monohydric alcohols or phenols
• CPC Class Codes: C08F 220/44 Acrylonitrile
• CPC Class Codes: C08J 2323/02 not modified by chemical after treatment
• CPC Class Codes: C08J 2433/00 Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
• CPC Class Codes: C08J 7/0427 with only one layer of a composition containing a polymer binder with more layers C08J7/042
• CPC Class Codes: C08J 7/043 Improving the adhesiveness of the coatings per se, e.g. forming primers adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C09D 133/062 Copolymers with monomers not covered by C09D133/06
• CPC Class Codes: C09J 133/062 Copolymers with monomers not covered by C09J133/06
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2848 Three or more layers
• CPC Class Codes: Y10T 428/2852 Adhesive compositions
• CPC Class Codes: Y10T 428/31515 As intermediate layer
• CPC Class Codes: Y10T 428/31862 Melamine-aldehyde
• CPC Class Codes: Y10T 428/31913 Monoolefin polymer
• CPC Class Codes: Y10T 428/31938 Polymer of monoethylenically unsaturated hydrocarbon

Abstract

A cold sealable emulsion-polymerized polymer cohesive formulation for coating a polyolefin film, preferably polypropylene, which has low surface tack characteristics and low blocking tendencies to an acrylic-based formulation prepared from the emulsion polymerization of acrylonitrile and one or more of a first soft monomer and a second functional monomer. A first soft monomer is any one of ethyl acrylate, hexyl acrylate, iso-octyl acrylate, butyl acrylate, isobutyl acrylate, methyl acrylate, 1,3-butadiene, vinylacetate and vinylidene chloride, and a second monomer is any one of methacrylic acid, acrylic acid, itaconic acid, crotonic acid, sulfoethyl methacrylate and maleic acid. The monomers are combined in weight percent amounts sufficient to achieve a glass transition temperature of at least about -35° C.

Claims

1. A coated polyolefin substrate which comprises a polyolefin film having a first side and a second side and a cold sealable, emulsion polymerized pressure sealable cohesive polymer composition for coating the first side of the substrate and an acrylic-based composition for coating the second side of the substrate, the polymer for coating the first side of the substrate comprising an acrylonitrile monomer and at least one of:

(a) a soft monomer selected from the group consisting of methyl acrylate, ethyl acrylate, hexyl acrylate, iso-octyl acrylate, butyl acrylate, isobutyl acrylate, isopropyl acrylate and vinyl acetate; and

(b) a monomer selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, sulfoethyl methacrylate and maleic acid;

the monomers being combined in weight percent amounts based on the total weight of the polymer sufficient to achieve a glass transition temperature of at least about -35°

C., the weight percent amounts of the acrylonitrile monomer ranges from about 10 wt. % to about 65 wt. %, the weight percent amount of the (a) monomer ranges from about 30 wt. % to about 85 wt. % and the weight percent amount of the (b) monomer ranges from about 1 wt. % to about 3 wt. %, based on the total weight of the polymer, the polmer having low blocking tendencies to the acrylic-based formulation of the second side of the substrate.

2. The coated substrate as described in claim 1 in which the acrylic-based formulation further comprises a component selected from the group consisting of methyl acrylate, methyl methacrylate, and methacrylic acid with the provision that each of the (a) and (b) monomer is different from this component.

3. The coated substrate as described in claim 2 in which the polymeric portion of the acrylic-based formulation comprises at least about 80 wt. % acrylic, based on the total weight of the polymer.

4. The coated substrate as described in claim 1 in which the soft monomer of (a) is ethyl acrylate and the monomer of (b) is methacrylic acid.

5. The coated substrate as described in claim 1 in which the acrylonitrile monomer is an ethyleneically unsaturated nitrile.

6. The coated substrate as described in claim 5 in which the weight percent among of each monomer is sufficient to achieve a glass transition temperature ranging from about -30°

C. to 15°

C.

7. The coated substrate as described in claim 1 in which the substrate comprises an oriented polypropylene film.

8. The coated substrate as described in claim 1 in which the polymer for treating the first side of the substrate further comprises a crosslinking agent.

9. The coated substrate as described in claim 8 in which the crosslinking agent is divinylbenzene.

10. The coated substrate as described in claim 1 in which the first and/or second side of the substrate is coated with a primer located between the polyolefin film and the acrylic-based composition and/or the polymer.

11. The coated substrate as described in claim 10 in which the primer is an epoxy primer.

12. The coated substrate as described in claim 10 in which the primer is melamine formaldehyde or polyethyleneimine.

13. The coated substrate as described in claim 1 in which the polymer for coating the first side of the substrate further comprises particulates ranging in size from about 6 to 9 microns in a concentration which is less than about 10 wt. % based upon the entire weight of the coating.