A PACKAGING MATERIAL FOR PACKAGING OF LIQUID AND FOOD

Abstract

The invention discloses a paperboard for packaging of a heat-sealable packaging material comprising: —a paperboard substrate comprising a first and a second side, —a first and an optional second dispersion coating layer on the first side, which first and optional second dispersion coating layer provides a barrier against at least one of liquid, moisture, grease and gas, —an extrusion coated barrier layer comprising a polyolefin, wherein the first and optional second dispersion coating layer is applied between the paperboard substrate and the extrusion coated barrier layer, and wherein the coat weight of the extrusion coated barrier layer is less than 15 gsm. The packaging material according of the invention minimizes the amount of plastic coating, but still provides the needed barrier properties for the packaging of food and/or liquid. The packaging material has especially been shown to provide a longer shelf life for food items packed in a packaging made from the material. Especially, the packaging material provides gas-, liquid and/or grease barrier properties. Although the packaging material comprises such low amount of extruded thermoplastic polymers, the material is readily heat-sealable.

Claims

1. A heat-sealable packaging material comprising: a paperboard substrate comprising a first side and a second side, a first dispersion coating layer on the first side, wherein the first dispersion coating layer provides a barrier against at least one of liquid, moisture, grease and gas, an extrusion coated barrier layer comprising a polyolefin, wherein the first dispersion coating layer is applied between the paperboard substrate and the extrusion coated barrier layer, and wherein a coat weight of the extrusion coated barrier layer is less than 15 gsm.

2. The heat-sealable packaging material according to claim 1, wherein the extrusion coated barrier layer constitutes less than 5 wt % of a total weight of the packaging material.

3. The heat-sealable packaging material according to claim 1, wherein the heat-sealable packaging material exhibits a water absorption rate of below 15 g/m.sup.2 as measured using COBB 600 in accordance with SCAN-P 12:64, or a Water Vapor Transfer Rate (WVTR) of less than 15 g/m.sup.2/24 h as measured using ASTM F1249, or both.

4. The heat-sealable packaging material according to claim 1, wherein the heat-heat sealable packaging material exhibits an oxygen transfer rate (OTR) of below 50 cc/m.sup.2*day*atm as measured according to ASTM D3985, 23° C., 50% relative humidity (RH).

5. The heat-sealable packaging material according to claim 1, wherein the heat-sealable packaging material comprises less than 10 pinholes/m.sup.2 as measured according to standard EN13676:2001.

6. The heat-sealable packaging material according to claim 1, wherein an amount of rejects received from re-pulping of the heat-sealable packaging material (determined according to PTS test method RH021/97) is less than 12 wt % based on a dry weight of the packaging material of 100 weight %.

7. The heat-sealable packaging material according to claim 1, wherein the heat-sealable packaging material exhibits a KIT value of above 10 as measured in accordance with TAPPI 559.

8. The heat-sealable packaging material according to claim 1, wherein a grease resistance of a folded and creased heat-sealable packaging material is at least 20 h according to ASTM F119-82 (60° C.).

9. The heat-sealable packaging material according to claim 1 further comprising a second extrusion coated barrier layer comprising a polyolefin, wherein a sum of a weight of the extrusion coated barrier layer and the second extrusion coated barrier layer is less than 15 gsm.

10. The heat-sealable packaging material according to claim 1, wherein the first dispersion coating layer comprises a latex, or a polyolefin, or both.

11. The heat-sealable packaging material according to claim 1 further comprising: a second dispersion coating layer applied on the first dispersion coating layer, wherein the first and second dispersion coating layers are applied between the paperboard substrate and the extrusion coated barrier layer.

12. The heat-sealable packaging material according to claim 11, wherein the first dispersion coating layer comprises latex and the second dispersion coating layer comprises a polyolefin.

13. The heat-sealable packaging material according to claim 12, wherein the second dispersion coating layer comprises a polyolefin selected from a group consisting of polyethylene (PE), polypropylene (PP), copolymers of polyethylene and polypropylene, and combinations thereof.

14. The heat-sealable packaging material according to claim 12, wherein the first dispersion coating layer comprises latex and the second dispersion coating layer comprises latex.

15. The heat-sealable packaging material according to claim 1, wherein a third dispersion coating layer is applied on the second side of the paperboard substrate.

16. A method to produce a packaging material comprising the steps of: providing a paperboard substrate comprising a first side and a second side, applying, in a first coating step, at least one first dispersion coating layer on the first side, wherein the at least one first dispersion coating layer provides a barrier against at least one of liquid, moisture, grease and gas, thereby forming a dispersion coated substrate, drying said dispersion coated substrate, and, applying, in a second coating step, a barrier coating layer comprising a polyolefin on said dispersion coated substrate by extrusion coating, wherein the barrier coating layer is applied in a coat weight of less than 15 gsm.

17. The method to produce a packaging material according to claim 16, wherein the at least one first dispersion coating layer is applied on the first side of the paperboard substrate by use of an impact coating method.

18. The method to produce a packaging material according to claim 16, wherein said first and said second coating step are applied integrated within the same coating line.

19. A packaging comprising or being made from the heat-sealable packaging material according to claim 1.

20. The packaging according to claim 19, wherein the packaging is for a liquid, or a food, or both.

Description

[0066] Further features of the present invention will become apparent from the examples and figures, wherein:

[0067] FIG. 1 is a schematic drawing of a packaging material according to an embodiment of the invention.

[0068] FIG. 2 is a schematic drawing of a packaging material according to a further embodiment of the invention.

[0069] The packaging material shown in FIG. 1 comprises a paperboard substrate (1). The paperboard substrate has a first and a second side, wherein on the first side the paperboard substrate is coated with a first dispersion coating layer (2) providing a barrier against liquid, moisture, grease and/or gas. A layer of polyolefin (3), such as of polyethylene or polypropylene, is extrusion coated on the first dispersion coating layer (2). The extrusion coated layer (3) will be in contact with the content of a packaging formed from the packaging material. The second side of the paperboard substrate 1 may be coated with a second dispersion coating layer (4), wherein the dispersion coating layer (4) forms the printing surface of the packaging material.

[0070] The packaging material shown in FIG. 2 comprises a paperboard substrate 1. The paperboard has a first and a second side, wherein on the first side the paperboard substrate is coated with a first and a second dispersion coating layer (2, 2′). A first and a second layer of polyolefin (3, 3′) is extrusion coated on the second dispersion coating layer (2′). The second extrusion coated layer (3′) will be in contact with the content of the packaging formed from the packaging material. The second side of the paperboard substrate (1) is coated with a second dispersion coating layer (4).

[0071] The paperboard as shown in FIG. 1 or 2 is particularly suitable for heat-sealed packages for liquid and/or food.