Laminated packaging material, packaging containers manufactured therefrom and a method for manufacturing the laminate material

Patent metadata

Field	Value
Publication number	US-11097868-B2
Application number	US-201816616801-A
Country	US
Kind code	B2
Filing date	May 31, 2018
Priority date	May 31, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

The present invention relates to a laminated liquid food packaging material, comprising a bulk layer of paper or carton or other cellulose-based material and outer layers of thermoplastic polymers on both sides, having a decorative print pattern arranged beneath one of the outer thermoplastic polymer layers. The invention further relates to the method for manufacturing the laminated packaging material and to a packaging container for liquid food packaging, comprising the laminated packaging material.

First claim

The invention claimed is:

1. Laminated packaging material for packaging of liquid food, comprising a cellulose-based bulk material layer, an outermost, transparent and protective thermoplastic polymer layer arranged on the outside of the cellulose-based bulk material layer, the outside of the cellulose-based bulk material layer being directed to the exterior of a packaging container made from the laminated packaging material, an innermost, heat sealable and liquid-tight thermoplastic polymer layer, to be in direct contact with the liquid food in the packaging container, a decorative print pattern arranged between the cellulose-based bulk material layer and the outermost, transparent and protective thermoplastic polymer layer such that the decorative print pattern is visible through the outermost, transparent and protective thermoplastic polymer layer, and wherein the laminated packaging material further comprises a cellulose-based print substrate paper, adhered to the outer side of the cellulose-based bulk material layer by 1-4 g/m 2 adhesive, dry weight, and having an outside print surface for carrying the decorative print pattern, the cellulose-based print substrate paper being laminated between the outside of the cellulose-based bulk material layer and the outermost transparent and protective thermoplastic polymer layer, and having a density higher than 650 kg/m 3 , a surface weight of 100 g/m 2 or lower (ISO 536), and comprising at least one sizing agent at from 0.1 to 0.4 weight-%, the outside print surface having a Bendtsen surface roughness value lower than 100 ml air/min (ISO 8791-2) and a Cobb value greater than 20 g/m 2 and lower than 30 g/m 2 (water).

2. Laminated packaging material as claimed in claim 1 , wherein the outside print surface of the cellulose-based print substrate paper has a Cobb value from 22 to 28 g/m 2 .

3. Laminated packaging material as claimed in claim 1 , wherein the outside print surface of the cellulose-based print substrate paper has a Bendtsen surface roughness value of below 80 ml air/min.

4. Laminated packaging material as claimed in claim 1 , wherein the cellulose-based print substrate paper has a surface weight of lower than 80 g/m 2 .

5. Laminated packaging material as claimed in claim 1 , wherein the cellulose-based print substrate paper has a tensile strength index (GM) of at least 40 Nm/g.

6. Laminated packaging material as claimed in claim 1 , wherein the cellulose-based print substrate paper has tear strength index of at least 6 mNm 2 /g.

7. Laminated packaging material as claimed in claim 1 , wherein the cellulose-based print substrate paper is a paper selected from the group consisting of MG (Machine Glazed) paper, MF (Machine Finished) paper, LWC (Light-weight coated) paper, Flexible Packaging paper, metallization base paper, digital printing paper, copy paper and ink jet printing paper.

8. Laminated packaging material as claimed in claim 1 , wherein the outside print surface of the cellulose-based print substrate paper is metallised and has a surface roughness lower than 100 ml air/min (Bendtsen).

9. Laminated packaging material as claimed in claim 1 , wherein the outside print surface of the cellulose-based print substrate paper is natural brown.

10. Laminated packaging material as claimed in claim 1 , wherein the cellulose-based bulk material layer is a liquid-packaging grade paperboard having a surface weight from 100 to 300 g/m 2 .

11. Laminated packaging material as claimed in claim 1 , further comprising a gas barrier film or foil laminated between the inner side of the cellulose-based bulk material layer and the innermost, heat sealable and liquid-tight thermoplastic polymer layer.

12. Liquid food packaging container comprising the laminated packaging material as defined in claim 1 .

13. Laminated packaging material as claimed in claim 1 , further comprising an aluminium foil laminated between the inner side of the cellulose-based bulk material layer and the innermost, heat sealable and liquid-tight thermoplastic polymer layer.

14. Method for manufacturing the laminated packaging material as defined in claim 1 , comprising:
providing a first web of the cellulose-based bulk material layer,
providing a second web of the cellulose-based print substrate paper, having the outside print surface for receiving and carrying the decorative print pattern, the cellulose-based print substrate paper having the density higher than 650 kg/m 3 , the surface weight of 100 g/m 2 or lower (ISO 536), and comprising the at least one sizing agent at from 0.1 to 0.4 weight-%, the outside print surface having the Bendtsen surface roughness value lower than 100 ml air/min (ISO 8791-2), and the Cobb value (ISO 535) greater than 20 g/m 2 and lower than 30 g/m 2 (water),
applying an aqueous adhesive composition comprising the adhesive, which is an adhesive polymer, at the amount from 1 to 4 g/m 2 , dry content, onto the surface of one of the first and second webs,
forwarding the first and second webs, one of which having the aqueous adhesive composition applied to its surface, towards a pressure roller nip to be joined and laminated together by the interjacent aqueous adhesive composition while passing the nip, and while the aqueous adhesive composition is partly absorbed into at least one of the first and second web surfaces,
printing the decorative print pattern onto the outside print surface of the cellulose-based print substrate paper,
laminating the innermost, heat sealable and liquid-tight thermoplastic polymer layer on the inner side of the web of the cellulose-based bulk material layer, opposite the side of the cellulose-based print substrate paper,
laminating the outermost, transparent and protective thermoplastic polymer layer on the outside print surface of the web of the cellulose-based print substrate paper, the outside print surface being opposite the side of the cellulose-based bulk material layer.

15. Method as claimed in claim 14 , wherein the decorative print pattern is printed onto the outside print surface of the cellulose-based print substrate paper before the aqueous adhesive composition is applied and before the first and second webs are forwarded towards the pressure roller nip, such that the cellulose-based print substrate paper is first printed with the decorative print pattern in a separate printing operation.

16. Method as claimed in claim 14 , wherein the cellulose-based bulk material layer has been calendered to an outside surface roughness lower than 200 ml air/min (Bendtsen).

17. Method as claimed in claim 14 , wherein the cellulose-based bulk material layer is a liquid packaging paperboard (LPB) having a surface roughness lower than 120 ml air/min (Bendtsen).

Assignees

• Tetra Laval Holdings & Finance

Inventors

• Öhman Peter
• Toft Nils

Classifications

• B32B2307/582

  Tearability · CPC title

• B32B2439/62

  Boxes, cartons, cases · CPC title

• B65D75/48

  containing liquids, semiliquids, or pastes, e.g. cushion-shaped packages · CPC title

• B32B38/145

  Printing · CPC title

• B32B7/12 Primary

  using interposed adhesives or interposed materials with bonding properties · CPC title