Barrier coating for packaging materials

Abstract

A coating composition for packaging materials such as paper, corrugated cardboard, and plastic, wherein the composition comprises a thixotropic aqueous mixture containing at least one smectite clay, a water-soluble polymer, and a crosslinking agent for crosslinking the clay and the polymer, and is applied to a packaging material and treated to crosslink the clay and the polymer; and a method for improving the barrier properties of a packaging material and its use.

Claims

1. A thixotropic aqueous mixture for coating packaging materials, a) At least one type of smectite clay, b) Water-soluble polymer and c) A crosslinking agent capable of crosslinking smectite clay to a polymer, A thixotropic aqueous mixture containing the following:

2. The thixotropic aqueous mixture according to claim 1, wherein the crosslinking agent is an amino acid, optionally aminocaproic acid, ethyl aminocaproate, or lysine.

3. The thixotropic aqueous mixture according to claim 1 or 2, wherein the smectite clay is montmorillonite, laponite, hectorite, or any two or more mixtures thereof, and the smectite clay is sodium montmorillonite.

4. The thixotropic aqueous mixture according to any one of claims 1 to 3, wherein the water-soluble polymer is polyvinyl alcohol, gum arabic, or pectin, or any two or more mixtures thereof, and the water-soluble polymer is polyvinyl alcohol.

5. a) Sodium montmorillonite or laponite, b) Polyvinyl alcohol, and c) Aminocaproic acid or its ethyl ester A thixotropic aqueous mixture according to any one of claims 1 to 4, comprising:

6. The thixotropic aqueous mixture according to any one of claims 1 to 5, wherein the smectite clay is present in the thixotropic aqueous mixture in an amount of 0.5 to 3.5% by weight, optionally 1.0 to 3.0% by weight, or optionally 2.0% by weight.

7. The thixotropic aqueous mixture according to any one of claims 1 to 6, wherein the water-soluble polymer is present in the thixotropic aqueous mixture in an amount of 1.5 to 4.5% by weight, optionally 2.0 to 4.0% by weight, or optionally 3.0% by weight.

8. The thixotropic aqueous mixture according to any one of claims 1 to 7, wherein the crosslinking agent is present in the thixotropic aqueous mixture in an amount of 0.1 to 0.4% by weight, optionally 0.25% by weight.

9. The thixotropic aqueous mixture according to any one of claims 1 to 8, wherein the ratio of the smectite clay to the water-soluble polymer is 1:4 to 4:1, and optionally, the ratio of the smectite clay to the water-soluble polymer is about 2:

3.

10. The thixotropic aqueous mixture according to any one of claims 1 to 9, wherein the ratio of the smectite clay to the crosslinking agent is about 8:1, or the ratio of the water-soluble polymer to the crosslinking agent is about 12:

1.

11. The thixotropic aqueous mixture according to any one of claims 1 to 10, wherein the thixotropic aqueous mixture is a dispersion containing 1 to 8% solids, optionally 1 to 5% solids.

12. a) At least one type of smectite clay, b) Water-soluble polymer and c) A crosslinking agent capable of crosslinking the smectite clay to the polymer, A method for preparing a thixotropic aqueous mixture comprising dispersing in water.

13. a) Dispersing the smectite clay in water to form a smectite clay dispersion, b) Adding the crosslinking agent to the smectite clay dispersion to adjust the pH of the smectite clay dispersion and linking the crosslinking agent to the surface of the smectite clay to form a surface-modified smectite clay dispersion, c) Adding the water-soluble polymer to the surface-modified smectite clay dispersion, The method according to claim 12, including the method described in claim 12.

14. A method for preparing coated packaging material, i) Applying a thixotropic aqueous mixture to the surface of the packaging material, wherein the thixotropic aqueous mixture is a) At least one type of smectite clay, b) Water-soluble polymer and c) A crosslinking agent capable of crosslinking the smectite clay to the water-soluble polymer, Applying the thixotropic aqueous mixture containing, ii) Crosslinking the water-soluble polymer with the smectite clay, Methods that include...

15. A method for improving one or more barrier properties of a packaging material, wherein the method is i) Applying a thixotropic aqueous mixture to the surface of the packaging material, wherein the thixotropic aqueous mixture is a) At least one type of smectite clay, b) Water-soluble polymer and c) A crosslinking agent capable of crosslinking the smectite clay to the water-soluble polymer, Applying the thixotropic aqueous mixture containing the above, ii) Crosslinking the water-soluble polymer with the smectite clay, A method wherein one or more barrier properties of the coated packaging material are improved compared to an uncoated packaging material.

16. The method according to claim 15, wherein one or more barrier properties of the packaging material are gas permeable, and the gas permeability of the coated packaging material is reduced compared to that of an uncoated packaging material.

17. The method according to any one of claims 14 to 16, wherein the thixotropic aqueous mixture is applied to the surface of the packaging material via an immersion tank, a spray bar, a brush bed, an inkjet printer, a doctor's knife, a rotogram or any combination thereof.

18. The method according to any one of claims 14 to 17, further comprising preparing the thixotropic aqueous mixture by the method described in claim 12 or claim 13.

19. The method according to any one of claims 14 to 18, wherein the packaging material includes or consists of paper, corrugated cardboard, and / or plastic.

20. As a coating for packaging materials, or for improving one or more barrier properties of packaging materials, a) At least one type of smectite clay, b) Water-soluble polymer and c) A crosslinking agent capable of crosslinking the smectite clay to the polymer, Use of a thixotropic aqueous mixture containing the above.

21. The use according to claim 20, wherein the packaging material includes or consists of paper, corrugated cardboard, and / or plastic such as PET.

22. The method according to any one of claims 12 to 19 or the use according to claim 20 or 21, wherein the crosslinking agent is an amino acid, optionally aminocaproic acid, ethyl aminocaproate, or lysine.

23. The method or use according to any one of claims 12 to 22, wherein the smectite clay is montmorillonite, laponite, hectorite, or any two or more mixtures thereof, and optionally the smectite clay is sodium montmorillonite.

24. The method or use according to any one of claims 12 to 23, wherein the water-soluble polymer is polyvinyl alcohol, gum arabic, or pectin, or any two or more mixtures thereof, and optionally the water-soluble polymer is polyvinyl alcohol.

25. The thixotropic aqueous mixture is a) Sodium montmorillonite or laponite, b) Polyvinyl alcohol, and c) Aminocaproic acid or its ethyl ester The method or use according to any one of claims 12 to 24, including

26. The method or use according to any one of claims 12 to 25, wherein the smectite clay is present in the thixotropic aqueous mixture in an amount of 0.5 to 3.5% by weight, optionally 1.0 to 3.0% by weight, or optionally 2.0% by weight.

27. The method or use according to any one of claims 12 to 26, wherein the water-soluble polymer is present in the thixotropic aqueous mixture in an amount of 1.5 to 4.5% by weight, optionally 2.0 to 4.0% by weight, or optionally 3.0% by weight.

28. The method or use according to any one of claims 12 to 27, wherein the crosslinking agent is present in the thixotropic aqueous mixture in an amount of 0.1 to 0.4% by weight, optionally 0.25% by weight.

29. The method or use according to any one of claims 12 to 27, wherein the ratio of the smectite clay to the water-soluble polymer in the thixotropic aqueous mixture is 1:4 to 4:1, and optionally, the ratio of the smectite clay to the water-soluble polymer is about 2:

3.

30. The method or use according to any one of claims 12 to 29, wherein the ratio of the smectite clay to the crosslinking agent in the thixotropic aqueous mixture is about 8:1, or the ratio of the water-soluble polymer to the crosslinking agent in the thixotropic aqueous mixture is about 12:

1.

31. The method or use according to any one of claims 12 to 30, wherein the thixotropic aqueous mixture is a dispersion containing 1 to 8% solids, optionally 1 to 5% solids.

32. A coated packaging material prepared by the method according to any one of claims 14 to 19 and 22 to 31.

33. The covered packaging material according to claim 32, comprising or consisting of paper, corrugated cardboard, and / or plastic such as PET.

34. A box, carton, tray, bag, or bottle comprising the covered packaging material according to claim 32 or claim 33.

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