Very Thin Medium Density Fibreboards (MDF) with Paperboard-like Properties as Reusable Packaging Material

Folie 1 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Technology

Mat laying with Airlaid technology

Folie 9 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Technology

Mat laying with Airlaid technology

Folie 10 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Results

Burst index with respect to additive

wet-process cardboard

Folie 14 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Results

Burst index with respect to recovered paper content / layering

wet-process cardboard

Folie 15 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Results

Bending stiffness with respect to recovered paper / layering

wet-process cardboard

Folie 16 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Results

Foldability with respect to recovered paper / layering

wet-process cardboard

Folie 17 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel 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 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Contact persons

Institut für Holztechnologie Dresden gemeinnützige GmbH ▪ Tino Schulz [email protected] +49 351 4662 263 ▪ Christoph Wenderdel [email protected] +49 351 4662 256 ▪ Detlef Krug [email protected] +49 351 4662 342

Papiertechnische Stiftung Heidenau ▪ Alf-Mathias Strunz [email protected] +49 3529 551 684

Folie 20 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel Thank you!

Folie 21 57th International Convention of Society of Wood Science and Technology, Zvolen, June 23-27, 2014 Christoph Wenderdel