US 11,724,284 B2Granted

Method of manufacturing a film comprising microfibrillated cellulose

AssigneeStora Enso OYJ

InventorsLars Axrup, Isabel Knöös, Christian Aulin, Magnus Hillergren, Tom Lindström, Göran Ström

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Abstract

The method of the invention relates to a method of manufacturing a fibrous, oxygen barrier film by casting a suspension comprising microfibrillated cellulose onto a non-porous substrate in a number of subsequent steps with intermediate drying. The invention enables an efficient method to manufacture an MFC film by casting technology without the problems of cracks or voids formed in the film. By applying the MFC in several layers, with in-between drying, the distance the water has to diffuse through is shorter, whereby the evaporation is more efficient and the film properties are not negatively affected by the drying.

Claims18

Dependent claims

A method of manufacturing a fibrous, oxygen barrier film comprising the steps of:

providing at least a first and a second suspension each comprising microfibrillated cellulose (MFC) in an amount of at least 50 wt % calculated on the total solids content of said suspension,
applying said first suspension on a non-porous substrate to form a first web,
drying said first web to a solids content of at least 50 wt % in an intermediate drying step,
applying said second suspension comprising microfibrillated cellulose (MFC) onto the surface of said dried first web to form a second web,
drying the web, comprising said first and second web, in a final drying step to form a film having a basis weight of less than 40 g/m2 and an Oxygen Transmission Rate (OTR) value of below 10 ml/m2/per 24 h at 50% RH.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/481,688Filed 30 Jan 2018
Priority: SE 1750069-530 Jan 2017
Published: US 2020/0023409 A123 Jan 2020
Granted: 15 Aug 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

B05D 7/04
To macromolecular substances, e.g. rubber: to surfaces of films or sheets
D21H 11/18
Modified by a particular after-treatment: highly hydrated, swollen or fibrillatable fibres
B05D 1/02
Processes for applying liquids or other fluent materials: performed by spraying
B05D 1/30
Processes for applying liquids or other fluent materials: performed by gravity only, i.e. flow coating