TREATING WOOD Improving durability by preservation & modification Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Treating wood Wood preservation Wood modification thermal treatment fire/flame retardant chemical modification Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Why do we treat wood ? Natural restrictions of wood Durability resistance against biological attack of fungi and insects Shrinkage and swelling unequal swelling in greater dimensions Degradation UV, mechanical, fire Water adsorption and desorption Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Classical Wood Preservation Mechanism toxicity Disadvantages: emissions during production emissions during use emissions after use (waste stage) New legislation (the Netherlands-Europe) Public image Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Alternatives to classical wp Durable tropical hardwood species sustainable forest management (FSC) quality of plantation grown wood availability Use of other materials pvc steel aluminium Alternative treatment methods Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Wood preservation Treatment methods Vacuum - pressure Dipping, spraying Local treatment (pill, gasses) Heating Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably Foreco Dalfsen

Treatability of wood Impregnation of wood wood anatomy and density fluids heat transfer Reaction with the cell wall material structure of the cell wall chemical composition Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Treatability of wood Impregnation of wood wood anatomy and density Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably © SHR Hout Research

Treatability of wood Impregnation of wood - Classes easy - complete penetration possible moderate - min. 6 mm after 2,5 hours of pressure hard - max. 3-4 mm after 3-4 hours of pressure very hard - after 3-4 hours of pressure hardly any impregnation Dependant on wood specie Sapwood & Heartwood Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Classical wood preservation Tar oil - creosote Waterborne - metal salts (CCA) Organic solvent (PCP) Other Local preservation Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Classical wood preservation Aim improving the durability increasing the resistance against biological attack fungi insects Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Modification of wood More Aims Improving the durability increasing the resistance against biological attack Improving dimensional stability Aesthetic properties – Colour Hardness Water repellent Combination with flame retardant Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Modification of wood Improving the properties of wood by means of changing the molecules of wood No addition of toxic components Alteration of low-value-wood-species Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Improved wood properties High durability (fungi, insects) Reduced shrinkage and swelling UV-stability Strength properties (both + and -) LOWER MAINTENANCE Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Definition of modified wood Thermal treatment of wood: chemical modification of the cell wall as a result of (hydro) thermal treatment (Chemical) Modification of wood: when a true transformation of the chemical structure of cell wall material Alternative treatments of wood: non toxicity lumina filling (resin) treatments cell wall filling (resin) treatments true modification of the cell wall Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Levels of modified wood Lumina filling resin treatments Cell wall filling resin treatments True modification of the cell wall Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably Cell wall Cell lumen © SHR Hout Research

Mechanism of water uptake © SHR Hout Research

Resin treatments Filling lumina no penetration of cell wall Bulking penetration of cell wall cavities Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably © SHR Hout Research

Modification the cell wall Chemical alteration of cell wall polymers Substitution of OH-groups Cross linking Degradation of polymers (undesired) Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably © SHR Hout Research

Thermal modification of wood Wood exposed to high temperatures for long period Dry or hydro thermal treatment - one or several treatment steps Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Thermally modification wood Distinguishing different thermally treatment processes ! excluding oxygen nitrogen burning gasses steam (water damp) vacuum oil (vegetable oils) Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

A two steps process: 1 hydro-thermolysis165 °C °C dryingconventional 2 curing170 °C °C 1 2 (hydro) Thermal treatment example: The Process Principle of the Plato process Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably © SHR Hout Research

Oil Heat treatment (Menz) Increased temperature o C

State of the Art Europe 2004 Processes Plato (NL) Thermowood (SF) Perdure, NOW (F) Menz (D) AKBV (NL) Chalmers (S) Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

State of the Art Europe 2004 Commercial treatment plants: Thermowood (> 10 production sites) Plato (1 production site) Menz NOW, Perdure (producing) Acetylation plant (blue print) Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Challenges Up-scaling: equipment / knowledge high costs Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Challenges Commercialisation: co-operation chemical process industry and wood industry high investments costs demand / availability price of process public image / acceptance Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

Utilisation of modified wood ? Civil/waterworks Sheet piling Bridges Canal lining Garden wood Sheds Fences Poles Joinery Window frames Doors Cladding (Parquet) floors (Garden) furniture Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

More information The material in this presentation is partly delivered by SHR (Centre for Timber Research), who are experts in wood modification and preservation in The Netherlands For more information: Leonardo da Vinci Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably