very thin medium density fibreboards (mdf) with paperboard … · 2014-08-23 · very thin medium...

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

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

Packaging Material


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?

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.

Current situation


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.

Problem


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.

Objective


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.


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.


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_10Protein Pr_0 Pr_10 Pr_20 Pr_30 Pr_50Wheat flour Wf_0 Wf_10PVAc PV_0 PV_10


Technology

Mat laying with Airlaid technology


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.


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


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.


Results

Burst index with respect to additive

wet-process

cardboard


Results

Burst index with respect to recovered paper content / layering

wet-process

cardboard


Results

Bending stiffness with respect to recovered paper / layering

wet-process

cardboard


Results

Foldability with respect to recovered paper / layering

wet-process

cardboard


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.


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).


Contact persons

Institut für Holztechnologie Dresden gemeinnützige GmbH▪ Tino Schulz

[email protected]+49 351 4662 263

▪ Christoph [email protected]+49 351 4662 256

▪ Detlef [email protected]+49 351 4662 342

Papiertechnische Stiftung Heidenau ▪ Alf-Mathias Strunz

[email protected]+49 3529 551 684


Thank you!

very thin medium density fibreboards (mdf) with paperboard … · 2014-08-23 · very thin medium...

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