HEAT SEALABLE BARRIER COATING

• US 20200131708A1
• Filed: 04/26/2018
• Published: 04/30/2020
• Est. Priority Date: 04/28/2017
• Status: Active Grant

• Current Assignee: Sun Chemical Corporation
• Original Assignee: Sun Chemical Corporation
• Inventors: Triclot, Magali, Le Lain, Pierrick, Beche, Michel, Caron, Dominique, Turgis, Jean-Dominique
• Granted Patent: US 11,555,276 B2
• Time in Patent Office: Days
• CPC Class Codes: B65D 5/563 Laminated linings; Coatings
• CPC Class Codes: B65D 65/42 Applications of coated or impregnated materials
• CPC Class Codes: C08L 23/06 Polyethene
• CPC Class Codes: C09D 133/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09D 191/06 Waxes
• CPC Class Codes: D21H 19/18 comprising waxes
• CPC Class Codes: D21H 19/20 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: D21H 19/40 siliceous, e.g. clays
• CPC Class Codes: D21H 19/58 Polymers or oligomers of diolefins, aromatic vinyl monomers or unsaturated acids or derivatives thereof
• CPC Class Codes: D21H 21/16 Sizing or water-repelling agents
• CPC Class Codes: D21H 27/10 Packing paper packaging materials of special type or form B65D65/38

Abstract

The present invention provides a heat-sealable water-based coating composition suitable for coating substrates used for packaging of products that contain grease, oil, water, etc. The coating compositions comprise acrylic polymer or copolymer emulsions and melting waxes. The substrates may be formed into containers, such as cups, for example. The coatings provide a barrier that is resistant to the permeation of, for example, grease, oil, water, and other liquids. Furthermore, the coating compositions are compostable.

Claims

1. A heat sealable water-based coating composition comprising:

a) 5 wt % to 90 wt % one or more acrylic polymer or copolymer emulsions;

b) 2 wt % to 25 wt % one or more melting waxes; and

c) 5 wt % to 85 wt % water;

wherein the heat sealable water-based coating composition is compostable.

2. The composition of claim 1, wherein the melting wax has a melting point of 40°

C. to 100°

C.

3. The composition of claim 1, wherein the one or more melting waxes are selected from the group consisting of paraffin wax, acrylic-grafted paraffin wax, crystalline wax, polyethylene wax, high density polyethylene wax, polyethylene/polytetrafluorethylene wax, carnauba wax, and combinations thereof and/or wherein the one or more acrylic polymer or copolymer emulsions are selected from the group consisting of pure acrylic polymer, ethylene acrylic acid copolymer, vinyl acrylic acid copolymer, styrene-acrylic copolymer, and combinations thereof.

5. The composition of claim 1, further comprising one or more additives selected from the group consisting of adhesion promoters, light stabilizers, de-gassing additives, flow promoters, defoamers, antioxidants, stabilizers, wetting agents, surfactants, clays, fillers, dispersants, plasticizers, rheological additives, other waxes, silicones, colorants, and combinations thereof.

6. The composition of claim 1, wherein the coating composition is a barrier coating composition, resistant to permeation of liquids and vapors.

8. The composition of claim 1, wherein the composition is recyclable, biodegradable, and compostable.

9. A substrate comprising the coating composition of claim 1.

10. The substrate of claim 9, which is cellulosic.

12. An article comprising the substrate of claim 9.

14. A method of coating a substrate comprising:

a) providing a substrate having a first surface and a second surface;

b) providing the heat sealable coating composition of claim 1;

c) applying the heat sealable coating composition to the first surface, or the second surface, or both the first surface and the second surface, of the substrate;

d) heating the coating at a sufficient temperature to melt the wax in the coating, wherein the melted wax permeates the paper fibers; and

e) sealing the substrate by applying pressure;

wherein the heat sealable barrier coating is compostable.

15. The method of claim 14, wherein the substrate is a cellulosic substrate.

17. The method of claim 14, wherein multiple layers of the heat sealable water-based barrier coating are applied to the substrate.

18. The method of claim 14, wherein the coating is applied by gravure printing, flexographic coating, curtain coating, flood coating, or Meyer bar application.

19. The method of claim 14, wherein the coating is applied at a dry coating weight of 2 g/m² to 15 g/m².

21. The method of claim 14, wherein the coating composition is applied to the first surface of the substrate as a flood coat, then the coating is applied to the second surface in registration so as to leave the sealing edges of the second surface uncoated to allow wax penetration into the seal.

25. The method of claim 14, further comprising applying a coating to the substrate that is wax-free.

26. A heat sealed substrate prepared by the method of claim 14.

27. The substrate of claim 26, wherein the substrate is resistant to water, grease, and oil.

32. The substrate of claim 26, wherein the substrate is compostable;

and/or wherein the substrate is repulpable.

34. The substrate of claim 9, wherein the substrate is compostable;

and/or wherein the substrate is repulpable.

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