Method of manufacturing of a foam-formed cellulosic fibre-material, a bulk sheet and a laminated packaging material comprising the cellulosic fibre-material

A method for manufacturing a foam-formed cellulosic fibre-material, comprising:

• (a) providing an aqueous foam comprising a gas dispersed as bubbles in an aqueous phase, wherein said aqueous phase comprises a surfactant;
• (b) adding cellulose fibres to the aqueous foam, thus forming a fibrous foam composition, wherein the cellulose fibres are added as
• coarse cellulosic fibres, selected from the group consisting of mechanical, chemi- mechanical, thermomechanical, chemithermomechanical pulp (CTMP) fibres and Neutral Sulfite Semi Chemical (NSSC) pulp fibres, in an amount of 85% to 97%, by weight of the total amount of cellulose fibres, wherein the coarse cellulosic fibres have a Canadian Standard Freeness value of 400-750 ml;
• and
• a cellulose reinforcement fraction in an amount of 6% to 12%, by weight of the total amount of cellulose fibres, wherein the cellulose reinforcement fraction is a heavily refined fibre component selected from the group consisting of heavily refined chemical pulp having a SR range higher than SR°80, heavily refined chemithermomechanical pulp (hrCTMP) having a CSF less than 70 mL, and a combination thereof, wherein the fibrous foam composition comprises a starch in an amount of 1 to 4% based on dry solids content of the fibrous foam composition;
• (c) distributing the fibrous foam composition onto a substrate or into a mould;
• and
• (d) reducing the amount of water in the distributed fibrous foam composition to obtain the foam-formed cellulosic fibre-material in its final shape, wherein the foam-formed material produced by the method has a density of 200 to 450 kg/m3 and a delamination strength of at least 100 J/m2.