Method of manufacturing a laminated cellulose-based liquid or semi-liquid food packaging material, for heat sealing into packages having sufficient mechanical strength and barrier properties, as well as an attractive outside appearance, comprising the steps of a) providing a web of a center module of bulk material comprising a cellulose spacer layer, which has a density below 850 kg/m 3, and a grammage from 60 to 250 g/m 2, and is a containerboard material having a bending stiffness at least 30 % lower than the bending stiffness of a liquid carton paperboard, at a corresponding grammage when excluding the printable coating (clay-coat) grammage, and a Short Compression Test Index (SCT Index) value of at least 30 Nm/g in the machine direction, as determined in accordance with ISO 9895 and ISO 536, b) providing a web of an outside material module, comprising a paper facing layer having a printable or printed surface directed towards the outer side of the module, and is laminated to the outside surface of the bulk material by an intermediate bonding layer or adhesive, the outside material module being intended for that side of the center module bulk material, which is to be directed to the outside of a packaging container made from the laminated packaging material, c) laminating the outside of the web of the center module bulk material and the web of the outside material module to each other, by applying an aqueous adhesive composition at an amount from 0,5 to 4 g/m 2 to one of the surfaces to be laminated to each other and pressing them together, d) adding the decor to the outside material module, e) providing a web of an inside material module, comprising a paper facing layer having a barrier coating, the inside material module being intended for that side of the bulk material, which is to be directed to the inside of a packaging container made from the laminated packaging material, f) laminating the web of the inside material module and the inside of the web of the center module bulk material to each other, by applying an aqueous adhesive composition at an amount from 0,5 to 4 g/m 2 to one of the surfaces to be laminated to each other and pressing them together, g) applying an outermost, transparent and liquid-tight protective layer on the outside of the outside material module, h) applying an outermost thermoplastic, liquid-tight and heat sealable layer on the inside of the inside material module, i) thus obtaining a web of the laminated cellulose-based liquid- or viscous-food packaging material, wherein the spacer layer constitutes the center of a sandwich structure within the laminated packaging material, the sandwich structure having at least one paper facing layer arranged on at least one side of the spacer layer and interacting with a further paper facing layer arranged on the other side of the spacer layer, the paper facing layer and the further paper facing layer having significantly lower thickness and a higher Young's modulus than the spacer layer. a) providing a web of a center module of bulk material comprising a cellulose spacer layer, which has a density below 850 kg/m 3, and a grammage from 60 to 250 g/m 2, and is a containerboard material having a bending stiffness at least 30 % lower than the bending stiffness of a liquid carton paperboard, at a corresponding grammage when excluding the printable coating (clay-coat) grammage, and a Short Compression Test Index (SCT Index) value of at least 30 Nm/g in the machine direction, as determined in accordance with ISO 9895 and ISO 536, b) providing a web of an outside material module, comprising a paper facing layer having a printable or printed surface directed towards the outer side of the module, and is laminated to the outside surface of the bulk material by an intermediate bonding layer or adhesive, the outside material module being intended for that side of the center module bulk material, which is to be directed to the outside of a packaging container made from the laminated packaging material, c) laminating the outside of the web of the center module bulk material and the web of the outside material module to each other, by applying an aqueous adhesive composition at an amount from 0,5 to 4 g/m 2 to one of the surfaces to be laminated to each other and pressing them together, d) adding the decor to the outside material module, e) providing a web of an inside material module, comprising a paper facing layer having a barrier coating, the inside material module being intended for that side of the bulk material, which is to be directed to the inside of a packaging container made from the laminated packaging material, f) laminating the web of the inside material module and the inside of the web of the center module bulk material to each other, by applying an aqueous adhesive composition at an amount from 0,5 to 4 g/m 2 to one of the surfaces to be laminated to each other and pressing them together, g) applying an outermost, transparent and liquid-tight protective layer on the outside of the outside material module, h) applying an outermost thermoplastic, liquid-tight and heat sealable layer on the inside of the inside material module, i) thus obtaining a web of the laminated cellulose-based liquid- or viscous-food packaging material,