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Woodforce, manufactured by Sonae Indústria, is an engineered wood fibre for a new generation of biocomposites. The product itself has been designed to improve the targeted properties of plastic resin, and is scientifically proven to deliver superior mechanical properties, such as greater tensile strength and consistent properties for easy dosing.

In allegiance with Scion, this new-patented technology promotes weight and cost savings with design opportunities currently unavailable in the natural fibre sector. It is a natural alternative to glass fibre and a stronger option to the unpredictable and seasonally dependent agricultural fibre.

Most significant was the tensile strength improvement, which at 40% wood fibre loading was 82% higher than the base polymer.

The “ready-to-use”, long wood fibre pellets are capable of producing reinforced thermoplastic parts by injection moulding, extrusion blow-moulding and thermoforming. Woodforce’s homogenous consistent quality and controllable moisture content make the diced pellets an attractive proposition for either extruders or injection moulders.

The plastics most researched with Woodforce to date, are polypropylene (PP), polyethelene (PE) and polylactic acid (PLA), respectively.

To achieve blending and reinforcement in the above examples, the wood fibre was compound extruded plastics extrusion using a co-rotating twin screw extruder followed by injection moulding of the resulting pellets. Ensuring compatibility between the fibre and extracellular matrix was achieved through addition of coupling agents into the compound extruder.

This approach to utilising wood fibres also has the following advantages:


 * Existing capital (MDF plant) can be used and little additional investment is required to produce wood fibre dice for plastics processors.
 * Dangers of wood dust and low moisture content fibres is mitigated.
 * The dice can be readily packaged, transported and will flow through hoppers and feed systems. Hence they can be used in existing plastics processing infrastructure.

Woodforce is the commercial uptake of this technology for the automotive, consumer and packaging industries.

Production Process
The combining of cellulose-based material to plastics was originally developed over 25 years ago by extrusion machinery manufacturer ICMA San Giorgio and used by G.O.R. Appliczioni Speciali SpA to make door panels for FIAT cars. The materials for the process were pre-mixed and cram-fed.

Wood “fibre” is, strictly speaking, not the same as wood flour though, confusingly, the term “fibre” is used interchangeably for flours. Wood fibre, as opposed to wood flour, will typically be longer fibre-like rather than particle-like (flour) and may typically have average lengths of > 0.85mm, and more usually 1mm, and perhaps in 2-3mm range. Some powder (fines) may be present of the fibre products, but they are usually minor components and average lengths are thus greater in fibre rather than flour. In addition, often, fibre is more entangled or fluffy, of lower bulk density, and difficult to handle. The aspect ratio (length / diameter) of, for example, wood fibres may be > 10:1 and may typically be, for example, of the order 20:1, 25:1 or 40:1, 50:1, 70:1 or more, while “flour” may generally have aspect ratios of 1:1 to 4:1 or 5:1, and typically less than 8:1 or 10:1.

Medium density fibreboard (MDF) uses a high temperature thermomechanical pulp fibre to produce large panels for a variety of applications, such as furniture or internal mouldings. Due to the commercial scale of these operations and the use of heat to soften the fibres, MDF fibre is a low cost form of wood fibre. Additionally, it has an aspect ratio to allow reinforcing of composites (for example radiata pine approx 2.5mmx30um).

In the MDF process a thermosetting resin, typically urea-formaldehyde (UF) or related formaldehyde crosslinking resins, or other resins such as isocyanate resins, is added to the fibre, with fibre in a wet state, while it is exiting the refiner in the blowline. This gives extremely high surface coverage of the fibre at low resin loadings. The MDF process would not be usually associated with producing a thermoplastic precursor for further processing in extrusion or other thermoplastic operations. Ordinarily it produces a sheet product which is fibre-rich and bound with a rigid, cured, thermoset resin which is not readily thermoplastically processable or reprocessable or easily usable or useful in thermoplastic processes.

The invention provides a process of impregnating or coating binding wood and other natural fibres, such as cellulose based fibres, with a dispersed or dissolved polymer system (‘binder’), then pressing or consolidating the impregnated fibres under pressure, and preferably at elevated temperature, into sheet or mat wherein the fibres are held together largely by the binder and then chopping the sheets into feedstock pellets or fibre concentrates.

Object of the Invention




It is an object of the invention to provide an improved, or at least an alternative process or method for producing a composite product comprising fibres of a lignocellulosic material or natural fibres and a plastics material, for use as or in forming a feedstock in plastics manufacture, or for use as an intermediate product in other form, or as an end product.

Pellets or granules produced by the process of the invention facilitate extrusion, with good release of the fibre from the pellet in the extruder or other plastics manufacturing equipment. The use of a thermoset binder reduces the cost of the builder system and thus of the production of the wood-plastics composite feedstock product, relative to use of a thermoplastic binder alone, which provide good dispersion and release of the fibre from the wood-plastics feedstock pellet and plastics manufacture but at higher cost.

The long established medium density fibreboard (MDF) process including HTMP (high temperature thermo-mechanical pulping) for example may be utilised to convert wood, or other residue fibres, into fibre rich pellets or granules suitable for feeding into existing plastics processing equipment while retaining sufficient aspect ratio for reinforcing. The preservation of greater fibre length than wood flour making the resulting wood plastic composite (WPC) stronger and stiffer than those based on wood flour. HTMP refining is the lowest cost technology to convert biomass into lignocellulosic fibre in large quantities. Furthermore, the multiple sources and reliable supply of wood, not constrained by seasonality like agricultural fibres, is an advantage for any manufacturing operation.



The process of the invention can produce wood-plastics feedstock pellets with sufficient internal bond strength that the pellets have sufficient physical integrity for efficient handling in industrial processes, that are cheaper and may have better fire resistance than those utilising pure thermoplastic binding agents, and that are capable of releasing the individual wood fibres in the extruder or other plastics manufacturing equipment under conditions that permit the preservation of fibre length so as to facilitate the improved mechanical properties of the WPCs. The thermoplastic modified-thermoset binder formulation may also result in reduced interference with a coupling agent where used when the pellets are mixed with the plastics matrix. A further advantage may be limited dust production during pelletizing.

An important advantage of using long wood fibre instead of other wood fillers (particles, flour) is the reinforcement potential of the high fibre aspect ratio that allows strengthening of thermoplastics like polypropylene (PP) or high density polyethylene (HDPE) while at the same time playing the role of a filler, cost saver and petrochemical substitute. However it is well known that wood fibre and polyolefins are poorly compatible (hydrophilic/hydrophobic), hence a coupling agent (maelic anhydride modified polyolefin) may be used to improve the fibre adhesion/matrix adhesion, resulting in efficient load transfer from fibre to fibre and reinforce the composite strength.

Woodforce Plant
The Le Creusot plant in France, which is ISO 9001 certified, has been chosen to be the first production site for Woodforce. It has 2.2 million square feet of land, a 214,000 square foot production plant and 120 on-site employees. In 2012 its production capacity stands at 100,000 tonnes per year.