Moisture content of polyethylene coated solid fibreboard after industrial lamination

Abstract

Solid fibreboard is used mainly in highly demanding packaging applications. One solid fibreboard quality having six paper and paperboard layers, a thickness of 1.7 mm and polyethylene coating was studied. Several material tests on liquid water and water vapour penetration were done to assess the environmental moisture sources that change the material moisture content after the lamination process. The in-plane diffusion coefficient of the combined board was determined based on an integrated unsteady state moisture transport equation and moisture sorption measurements. The transverse diffusion coefficient of the polyethylene coated kraft paper and the solid fibreboard medium were based on water vapour transmission rate measurements. The original moisture content of the solid fibreboard sheet was measured gravimetrically 2 days after the lamination at the mill. The results show that high relative humidity (RH) conditions during the transportation (4°C/90% RH) change the moisture content of the transportation box made from a solid fibreboard sheet very little in 8 days. Local moister (or drier) INTRODUCTIONContainerboard is the largest grade group by volume in the paper industry, accounting for 31% (117 million tons) of the world's total paper and board production. 1 Corrugated containers make the majority of packaging production. Solid fibreboard is a multilayer paper-based packaging material often based on recycled fibres. The material can be finished with a variety of lining papers and optionally polyethylene coating. Most grades are glued together in an off-line laminator. Solid fibreboard boxes account for 0.5% of US total industry corrugated shipments.1 Solid fibreboard is mainly used in demanding packaging applications where the product is wet, frozen or greasy. The difference in consumption is reflected in the extent of research done on these materials.Several paperboard layers are glued together in a lamination process to form a solid fibreboard sheet. The glue contains water. The lamination process together with the moisture content of the sheets determines the original moisture content of the laminated paperboard. As a transport box, the sheet is exposed both to liquid water and water vapour. The exposure takes place through the edges and planes of the sheet. Mechanical properties of paper-based materials depend strongly on the moisture content of the material. 2 The strength of the container box is thus dependent on the initial moisture content after production, and how the material resists additional moisture penetration into the material. This work aims at evaluating the effect of different moisture sources in the environment on the moisture content of the sheet when it is used as a transport box. This topic is justified from a practical point of view, since the mechanical properties of the transport box folded from a solid fibreboard sheet depend on the evolvement of the material moisture content during transportation.In the present work, the original moisture content of a newly fabricated solid fib...

Evaluation of NaCl Effect on Vibration-Delaminated Metal-Polymer Composites by Improved Micro-Raman Methodology

“…e delamination of polymer protective coatings on metals, under humid environments, is associated to a complex number of physicochemical phenomena [2][3][4]. One of the widely accepted mechanisms is that the reaction forces involve the formation of electrochemical microcells with different anodic and cathodic zones which lead to detachment.…”