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

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

surface penetration/treatment

deep or complete treatment

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

cellulose

cellulose

OH

OH

OH

H

OH

OH

OH

H

OH

OH H

OOH

cellulose

cellulose

hydrogen bonds between two cellulose surfaces

hydrogen bonds between two cellulose surfaces and water

© SHR Hout Research

Resin treatments

Filling lumina no penetrationof cell wall

Bulkingpenetration of cell wall cavities

Leonardo da Vinci’ Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably

© SHR Hout Research

Modification the cell wall

Chemical alteration ofcell 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-thermolysis 165 °C - 185 °C

drying conventional2 curing 170 °C - 190 °C

1 2

Selectively reorganizing theSelectively reorganizing thechemistry of woodchemistry of wood

Cellulose

Hemicellulose

Lignin

CCCCrrrroooo ssss ssss lllliiiinnnnkkkkiiiinnnngggg

Water resistant

structure

RRRReeee aaaacccc ttttiiiivvvveeee iiiinnnntttteeee rrrrmmmmeeee ddddiiiiaaaatttteeee ssss IIII((((eeee ....gggg .... aaaallllddddeeee hhhhyyyyddddeeee ssss ))))

RRRReeee aaaacccc ttttiiiivvvveeee iiiinnnntttteeee rrrrmmmmeeee ddddiiiiaaaatttteeee ssss IIIIIIII

Cellulose

(hydro) Thermal treatmentexample: 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 180-220oC

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: www.shr.nl

Leonardo da Vinci’ Pilot Project, EURIS – Europeans Using Roundwood Innovatively & Sustainably