Heat-sealable packaging material

Patent metadata

Field	Value
Publication number	US-2021017717-A1
Application number	US-201816955900-A
Country	US
Kind code	A1
Filing date	Dec 19, 2018
Priority date	Dec 21, 2017
Publication date	Jan 21, 2021
Grant date	—

Abstract

The present invention is directed to a packaging material free from aluminium in the form of a continuous foil or film, comprising a layer of microfibrillated cellulose (MFC), wherein the layer comprising MFC has been laminated or coated on at least one side with a heat-sealable material. The MFC layer contains at least 60% by weight of microfibrillated cellulose. The present invention is also directed to a method for induction sealing, wherein a packaging material to be heat-sealed by induction is placed against an induction heating surface.

First claim

1 . A heat-sealable packaging material, free from aluminum in the form of a continuous foil or film, the heat-sealable packaging material comprising:
a layer that comprises at least 60% by weight of microfibrillated cellulose, wherein the layer comprising at least 60% by weight of microfibrillated cellulose is laminated or coated with a heat-sealable material.

2 . The heat-sealable packaging material according to claim 1 , wherein the heat-sealable material is selected from the group consisting of: polyethylene, polypropylene, polylactic acid, styrene acrylic latex, styrene butadiene latex, and mixtures thereof.

3 . The heat-sealable packaging material according to claim 1 , wherein a thickness of the heat-sealable packaging material is less than 70 μm.

4 . The heat-sealable packaging material according to claim 1 wherein at least one side of the heat-sealable packaging material is provided with a coating that prevents the at least one side from adhering to a heated metal surface.

5 . The heat-sealable packaging material according to claim 4 , wherein the coating that prevents the at least one side from adhering to a heated metal surface is selected from the group consisting of: starch, a wax, a mineral or pigment coating or a polymer having a higher melting point than a melting point of the heat-sealable material.

6 . The heat-sealable packaging material according to claim 1 , wherein said layer comprising at least 60% by weight of microfibrillated cellulose has been extrusion coated or dispersion coated with a thermoplastic polymer.

7 . The heat-sealable packaging material according to claim 6 , wherein said thermoplastic polymer is polyethylene.

8 . The heat-sealable packaging material according to claim 1 , wherein the microfibrillated cellulose is native microfibrillated cellulose, modified microfibrillated cellulose, or a mixture thereof, and wherein the modified microfibrillated cellulose is phosphorylated microfibrillated cellulose or PCC coated microfibrillated cellulose.

9 . A method of manufacturing the heat-sealable packaging material according to claim 1 , the method comprising the steps of
a) preparing the layer of at least 60% by weight of microfibrillated cellulose; b) laminating or coating the layer of step a) with the heat-sealable material on at least one side of the microfibrillated cellulose layer.

10 . (canceled)

11 . A method for induction sealing, wherein the material to be sealed by induction is free from aluminum in the form of a continuous foil or film, the method comprising:
bringing the heat-sealable packaging material according to claim 1 into close proximity or contact with a surface; heating the surface by induction, thereby heating and sealing, under applied pressure, the heat-sealable packaging material to provide a heat sealed package.

12 . The method according to claim 11 , wherein the sealing is achieved by softening or melting of the heat-sealable material and by applying a pressure to the softened or melted heat-sealable material.

Assignees

• Stora Enso Oyj

Inventors

• Backfolk Kaj
• Heiskanen Isto
• Saukkonen Esa
• Kankkunen Jukka

Classifications

• B32B2255/28

  Multiple coating on one surface · CPC title

• B32B2255/26

  Polymeric coating · CPC title

• B32B2255/20

  Inorganic coating · CPC title

• B32B2255/12

  on paper layer · CPC title

• B32B29/06

  specially treated, e.g. surfaced, parchmentised · CPC title