Very Thin Medium Density Fibreboards (MDF) with Paperboard-like Properties as Reusable Packaging Material Folie 1
Current situation Market data for cardboards for packaging (Germany) growth for period 2008 2012 of 12 %, production in 2012 of 10.5 mill. t of paper, card- and paperboards for packaging purposes, assortments and shares: brown paper and paper for corrugated boards (69 %), cardboard (27 %), mill board (1 %), wrapping paper (3 %). Market of packaging material shows great potential! Also for wood based panel industry? Folie 2
Current situation Calculation of production factors for 1 mm MDF in comparison to 1 mm cardboard. Thin MDF as substitute for cardboards as packaging material offers following advantages: savings in process water (¾ and more), lower energy consumption, omitting process chemicals, lower amortisation costs. production costs are possibly lower, very good carbon and water footprints. Folie 3
Problem Thin MDF are not suitable for the same applications as conventional cardboards for packaging purposes. Problem: Product properties, inadequate foldability, lack of recyclability. Production technology, laying of fibre mat, accuracy and speed of hot-press. Folie 4
Objective Development of dry cardboard possible to manufacture with state of the art MDF-technology, with grammages of 300 800 g/m², applicable as packaging material, guaranteed recyclability in waste-paper stream, acceptable foldability, comparable strength and stiffness in comparison to wet-process cardboard, ecological and economical advantages. Folie 5
Approach Technological adaption pneumatic-mechanical mat laying, adapted press parameters (temperature, time, pressure). Raw material fibre pulp MDF fibres with modified pulping conditions, addition of differently conditioned recovered paper, additives omitting conventional thermosetting condensation resins, use of natural binders such as starch, proteins. Folie 6
Materials Fibre pulp Raw material: Scots pine and recovered paper, Digester cond.: 160 C for 3-4 min., Defibrator: 12 inch laboratory refiner, Grinding gap: 60 µm, Driving speed: 3,000 rpm, Flash dryer temp.: 90 C. Folie 7
Materials Application of additives additives: starch, protein, wheat flour, PVAc, application: blowline, content: 10 % to absolutely dry mass of fibres. Additive Recovered paper content / % 0 10 20 30 50 Starch St_0 St_10 Protein Pr_0 Pr_10 Pr_20 Pr_30 Pr_50 Wheat flour Wf_0 Wf_10 PVAc PV_0 PV_10 Folie 8
Technology Mat laying with Airlaid technology Folie 9
Technology Mat laying with Airlaid technology Folie 10
Technology Production parameters grammages: 250 600 g/m², target density: 700 kg/m³, cardboard layer: single- and multilayer, MC fibre mat: rewetted to 13 %, spec. pressure: 5 10 bar, press temp.: 170 210 C, press time factor: 10 15 sec/mm. Folie 11
Characterisation Cardboard properties thickness DIN EN 20534 mass per unit area DIN EN ISO 536 burst index DIN 53141-1 bending stiffness DIN 53121 folding behavior DIN 55437-2 and DIN 55437-3 recyclability PTS-RH 021/97 and INGEDE-Methode 13 Folie 12
Characterisation Folding behaviour according to standard only differentiated between pass / fail test, Method to assess folding behaviour was established. 10 very good (passed test) 1 very poor. Folie 13
Results Burst index with respect to additive wet-process cardboard Folie 14
Results Burst index with respect to recovered paper content / layering wet-process cardboard Folie 15
Results Bending stiffness with respect to recovered paper / layering wet-process cardboard Folie 16
Results Foldability with respect to recovered paper / layering wet-process cardboard Folie 17
Conclusion Dry cardboards are feasible to manufacture with optimized raw material combination, adaptation of mat laying and optimising pressing process, excellent mechanical properties, fully given recyclability, acceptable foldability until now only in multilayer. Folie 18
Acknowledgement The presented work was supported by the German Federal Ministry of Economics and Technology at the decision of the German Bundestag (IGF: 16911 BG). Folie 19
Contact persons Institut für Holztechnologie Dresden gemeinnützige GmbH Tino Schulz tino.schulz@ihd-dresden.de +49 351 4662 263 christoph.wenderdel@ihd-dresden.de +49 351 4662 256 Detlef Krug detlef.krug@ihd-dresden.de +49 351 4662 342 Papiertechnische Stiftung Heidenau Alf-Mathias Strunz alf-mathias.strunz@ptspaper.de +49 3529 551 684 Folie 20
Thank you! Folie 21