Solvent blockers and multilayer barrier coatings for thin films

• US 5,225,288 A
• Filed: 05/21/1992
• Issued: 07/06/1993
• Est. Priority Date: 08/10/1990
• Status: Expired due to Term

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Cole, Raymond T., Leidolf, Herbeson H. Jr., Beeson, Charles L., Deak, Gedeon I.
• Primary Examiner(s): Sluby, P. C.
• Application Number:
  US07/886,311
• Time in Patent Office: 411 Days
• Field of Search: 428/36.7, 428/475.5, 428/476.1, 428/509, 428/510, 428/511, 428/514, 428/515, 428/516, 428/518, 428/520, 427/379, 427/393.5, 427/411, 427/412.1, 427/412.2, 427/412.3, 427/412.4, 427/412.5
• US Class Current: 428/475.5
• CPC Class Codes: B05D 2201/02 Polymeric substrate
• CPC Class Codes: B05D 2401/10 Organic solvent B05D2401/21 takes precedence
• CPC Class Codes: B05D 2401/20 Aqueous dispersion or solution
• CPC Class Codes: B05D 2451/00 Type of carrier, type of coating (Multilayers)
• CPC Class Codes: B05D 7/584 at least some layers being let to dry, at least partially, before applying the next layer B05D7/587 takes precedence
• CPC Class Codes: C08J 2423/06 Polyethene
• CPC Class Codes: C08J 2427/08 Homopolymers or copolymers of vinylidene chloride
• CPC Class Codes: C08J 2467/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C08J2467/06 takes precedence
• CPC Class Codes: C08J 7/042 with two or more layers, where at least one layer of a composition contains a polymer binder
• 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: C08J 7/048 Forming gas barrier coatings
• CPC Class Codes: C08J 7/052 Forming heat-sealable coatings
• CPC Class Codes: Y10T 428/31739 Nylon type
• CPC Class Codes: Y10T 428/31746 Polymer of monoethylenically unsaturated hydrocarbon
• CPC Class Codes: Y10T 428/31888 Addition polymer of hydrocarbon[s] only
• CPC Class Codes: Y10T 428/31891 Where addition polymer is an ester or halide
• CPC Class Codes: Y10T 428/31895 Paper or wood
• CPC Class Codes: Y10T 428/31906 Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31913 Monoolefin polymer
• CPC Class Codes: Y10T 428/3192 Next to vinyl or vinylidene chloride polymer
• CPC Class Codes: Y10T 428/31928 : Ester, halide or nitrile of addition polymer

Abstract

A film comprising alternating layers of polyvinylidene chloride resin and a solvent barrier such as polyvinyl alcohol provides superior barrier properties. Barrier and mechanical properties are enhanced when formulation additives are present at customary levels only in the outermost layers.

Claims

1. A coated film having good barrier and handling properties, comprising:

(a) a substrate film;

(b) at least one underlayer of vinylidene chloride polymer containing less than about 3 weight percent organic formulation additives; and

(c) at least one overlayer of vinylidene chloride polymer containing at least about 3 weight percent organic formulation additives.

2. The film of claim 1 wherein the underlayer of (b) contains less than about 1 weight percent organic formulation additives.

3. The film of claim 1 wherein the underlayer of (b) contains less than about 0.5 weight percent organic formulation additives.

4. The film of claim 1 further comprising at least one intermediate layer of vinyl alcohol polymer.

5. A coated film having good barrier, handling, and adhesive properties, comprising:

(a) a substrate film;

(b) at least one underlayer of a vinylidene chloride polymer containing less than about 3 weight percent organic formulation additives; and

(c) at least one overlayer of a heat sealable thermoplastic polymer which adheres to said underlayer of vinylidene chloride polymer.

6. The coated film of claim 5 wherein the overlayer is a copolymer of ethylene and a copolymerizable ester.

7. The coated film of claim 5 wherein the overlayer is ethylene vinyl acetate copolymer.

8. The coated film of claim 5 wherein the overlayer is a copolyester.

9. The coated film of claim 5 wherein the overlayer is a condensation polymer composed of ethylene glycol and 40/60 to 60/40 mole mixture of azelaic and terephthalic acids.