Barrier film or sheet and laminated packaging material comprising the film or sheet and packaging container made therefrom
Barrier films or sheets comprising cellulose nanofibrils and laminated packaging materials comprising such films, in particular for liquid food packaging, are disclosed. A packaging container comprising the laminated packaging material or being made from the laminated packaging material, in particular a packaging container for liquid food packaging, are also disclosed.
1. A laminated packaging material for use in packaging of products sensitive to oxygen and other gases, comprising:
a bulk layer of paper or paperboard or other cellulose-based material,
a first outermost, liquid tight, heat sealable polyolefin layer,
a second innermost, liquid tight, heat sealable polyolefin layer, and
a barrier sheet or film comprising cellulose nanofibrils (CNF) and optionally a plasticizer compound,
wherein the barrier sheet or film is arranged on the inner side of the bulk layer of paper or paperboard or other cellulose-based material, between the bulk layer of paper or paperboard or other cellulose-based material and the second innermost, liquid tight, heat sealable polyolefin layer,
wherein the barrier sheet or film is coated on at least one side with a first vapor deposition barrier coating of an amorphous diamond-like carbon (DLC),
wherein said vapor deposition barrier coating of an amorphous DLC is arranged between said barrier sheet or film and said second innermost, liquid tight, heat sealable polyolefin layer, and
wherein the vapor deposition barrier coating has water vapor barrier properties, whereby the barrier sheet or film provides gas barrier properties at high humidity conditions in the laminated packaging material.
2. The laminated packaging material as claimed in claim 1 , wherein the barrier sheet or film is a substrate layer coated with the CNF and optionally the plasticizer compound, and wherein the substrate layer is further coated with the vapor deposition barrier coating.
3. The laminated packaging material as claimed in claim 2 , wherein the substrate layer is a polymer film.
4. The laminated packaging material as claimed in claim 2 , wherein the substrate layer is a paper substrate having a grammage from 12-70 g/m 2 .
5. The laminated packaging material as claimed in claim 1 , wherein the barrier sheet or film comprises only one vapor deposition barrier coating on one side.
6. The laminated packaging material as claimed in claim 1 , wherein the barrier sheet or film comprises up to 25 weight-% of the plasticizer compound, based on the dry weight of the layer.
7. The laminated packaging material as claimed in claim 6 , wherein the plasticizer compound is selected from the group consisting of polyols, saccharides, polysaccharides, cellulose derivatives, polyethylene glycols and polyvinyl alcohols.
8. The laminated packaging material as claimed in claim 6 , wherein the plasticizer compound is selected from the group consisting of carboxymethyl cellulose (CMC), glycerol, polyethylene glycol (PEG) with a molecular weight from 2000 to 4000, and polyvinyl alcohols having a high degree of hydrolysis.
9. The laminated packaging material as claimed in claim 1 , wherein the barrier sheet or film is coated with said vapor deposition barrier coating on both sides.
10. The laminated packaging material as claimed in claim 1 , wherein a thickness of the DLC coating is from 2 to 40 nm.
11. The laminated packaging material according to claim 1 , wherein the barrier sheet or film is bonded to the bulk layer by an intermediate adhesive or a polymer bonding layer.
12. A packaging container comprising the laminated packaging material as claimed in claim 1 .
13. The laminated packaging material as claimed in claim 1 , wherein the barrier sheet or film is a film of the CNF and the plasticizer compound.