Final Report Summary - DURAWOOD (Development of a cost-effective, durable coating system with low-fungicide content for wood surfaces using plasma discharge)
Executive summary:
Wood used in outdoor applications is particularly susceptible to fungi and weathering leading to an insufficient durability especially when using water borne coatings. The DURAWOOD project developed a tailored plasma-based system for treating wood surfaces in continuous conditions suitable for industrial wood manufacturing. Tests conducted for different wood species showed that plasma can have different effects (temporary water repellence, improved wettability by different types of coatings resulting in improved adhesion, etc.). Therefore, in selected conditions, this pretreatment allows improving the quality of wood coated with waterborne coatings and helps wood processors to meet the European legislation by reducing volatile organic compounds (VOCs) emitted while using solvent based coatings (EC Directive 2004/42/EC).
Laboratory research conducted during the project showed that plasma can be used to modify wood surfaces in a fine tuned and versatile way. Upon performing over 10 000 experiments by varying the parameters of the plasma (various atmospheres, powers, treatment times, gaps, etc.), the conditions to make wood surface more hydrophilic or more hydrophobic were determined for different species at the laboratory scale. In addition, the effect of plasma was investigated by atomic force microscope (AFM) and infrared (IR) spectroscopy showing that a layer of hundred nm was modified on the wood surface. Polymerase chain reaction (PCR) methods were optimised to detect wood-decaying fungi. Methodology was also established for blue stain fungi according to well established standards. The tests of the efficiency of DURAWOOD in enhancing resistance against fungi were performed on many of the previous treatment conditions at the lab scale but also on the large wood panels treated in pre-industrial conditions. Tests indicated a large variability depending on the conditions of application of the plasma pretreatment and indeed of the coating and wood species. Therefore, experiments were performed on pre-inoculated wood samples showing a significant sterilisation effect of plasma in hydrophilisation conditions. The results were compared with simple experiments with ozone and UV treatments showing a much more efficient antifungal effect for DURAWOOD.
The lab set-up for plasma treatment was scaled up in order to treat the wood surface semi-continuously in a suitable way to integrate easily in wood factories. As such, the prototype integrates 2 plasma electrodes and allows the treatment of up to 30 m2 of wood per hour after sanding as a pretreatment before coating. It is adjustable to the treatment of wood panels of different sizes up to 40-centimetre width, 2-metre length and 10-centimetre thickness. It has really low energy consumption in the range of 1 KW and can operate with several gases including the cost-effective solution of simply using air or for example with a carbon dioxide (CO2) flow of less than 10 L / min.
The validation of the use of the prototype for pre-treating wood took place at the facilities of the project industrial partners in Slovakia and in Spain. The assessment of the quality of the resulting coated wood with and without plasma pretreatment was then carried out. This allowed confirming at large scale that the prototype still allowed a sufficiently fine gap regulation to lead to a significant change of the polarity of the wood both towards hydrophilisation and hydrophobisation depending on the desired effect, i.e. either to improve compatibility with respectively water borne coatings, or with solvent based coating (as an extra effect derived by the project and of interest for the industry but not a primary target) and temporary water repellence with solvent borne coatings. Therefore, adhesion tests and long term durability tests in terms of wood weathering were performed showing a positive effect of plasma in certain conditions and for selected wood specie and coating systems used in the different wood factories.
After this validation period, the DURAWOOD prototype was used during 2 demonstration sessions to industry.
Project context and objectives:
Wooden surfaces need to be durable in order to be attractive to customers and compete with other materials. Biological, physical and chemical pretreatments are generally applied to wood to improve its resistance to fungi causing decay and staining, its dimensional stability and its slightly increased equilibrium moisture content. But these classical wood treatment techniques present many drawbacks, such as energy inefficiency, and damage to the environment. In recent years, public concern about the environment has led to the creation of regulatory programmes to reduce air pollution, increasing the pressure on wood manufacturers to reduce harmful emissions derived from both chemical treatments (VOC) and thermal treatments (CO2). European legislation (EC Directive 2004/42/EC) on coating products is fuelling a shift away from the aforementioned towards waterborne coatings. However, wooden surfaces treated with waterborne coatings are more susceptible to discoloration and damage by wood-destructible and blue stain fungi. This situation presents serious challenges to the European wood processing industry.
Wettability is an important aspect of wood that influences its adhesive and coating quality. Wood has a relatively polar surface that allows the general use of waterborne coatings, however wood surfaces exposed to high temperature treatments are harder to wet. By producing high frequency electric discharges, plasma generates ionised gas that can modify the surface properties of the material it is in contact with. Plasma treatment is a versatile and powerful technique commonly used in many industries to activate the surface of materials such as plastics, textiles, glass and metals. However, before the DURAWOOD project, the use of plasma to treat wood has been limited to academic research.
Although low-pressure plasma processes have been studied for treating wood, atmospheric pressure processes are typically more attractive for wood industry applications because of their lower cost, higher throughput, and ability to operate in-line without vacuum systems. Atmospheric pressure plasma systems are typically based on volume dielectric barrier discharge (DBD) arrangement, where the treated material is placed between the discharge electrodes or the material itself works as one electrode. However, this arrangement is problematic for the treatment of thick wood materials where the process is highly energy intensive (due to resistive power losses) and as such, a high voltage is needed, leading to safety concerns. A more practical approach to solve the issue of power loss in the bulk of wood material, as pursued in the DURAWOOD project, is to use a planar plasma electrode, such as the diffuse coplanar surface barrier discharge (DCSBD). Due to the planar geometry of the discharge electrode, the electrical current and the discharge plasma are confined into a thin layer above the DCSBD electrode, presenting a high volume power density and thus generating a high concentration of reactive species.
In this context, the objective of this project centred on the development of a new industrial process (DURAWOOD) based on the application of plasma DCSBD to improve the coating adhesion of wood and therefore increase its durability, especially when using water borne coatings.
First, the participating small and medium-sized enterprises (SMEs), as well as a representative sample of European wood processors were consulted and results used to determine their needs and specifications and define the industrial specifications for the DURAWOOD prototype. This bottom-up approach ensured that the prototype which would be tested and validated in a real industrial environment, would meet not only the technological requirements of industry, but socio-economic requirements.
Second, laboratory research was carried out in order to validate the effectiveness of plasma technology for improving the wettability and waterproofing effects on wood surfaces. The aim was to generate highly hydrophobic wood surfaces as showed by significant contact angles increase, increase the wettability of the wood surface in order to increase coating adhesion and strength to ensure that wood treated with the DURAWOOD system developed during the project would require lower maintenance frequency. Positive results were observed with optimised plasma treatment conditions and selected coating systems. Then, an associated objective was to analyse the microbiological sensitivity of plasma treated and untreated wood to ensure that DURAWOOD treated wood offers at least the same resistance to attack from fungi and moulds when compared to woods treated with solvent-based coatings. To this end during this project traditional microbiological analyses were carried out, along with molecular analysis using the PCR method for analysing the presence of a selected number of moulds and fungi. The results were really dependent on the type of wood and conditions of the treatment.
Finally, the project aimed to design and build a pre-industrial prototype of the DURAWOOD system keeping with the previously defined specifications outlined and based on the laboratory set up. The aim was to deliver a DURAWOOD system that would be quick to apply, cost effective, deliver consistent product quality and constant treatment rates, capable of being easily and readily integrated into modern wood processing plants and of minimal environment impact. Then this prototype could be installed, tested and validated in a real industrial environment in the facilities of the wood manufacturers in the consortium. A further goal was to carry out demonstration activities proving the viability of the DURAWOOD system, outline its potential economic and environmental advantages. The overriding goal of this project was to ensure that the pre-competitive DURAWOOD prototype would fulfil the threshold requirements of the industry to ensure its further development post-project into a fully industrial system that would be taken to market, where its beneficial ecological impact could be felt at European level. This was also empowered by the realisation of dissemination activities throughout the project and the layout of an exploitation strategy by the consortium.
Project results:
The DURAWOOD project delivered a versatile, adjustable, scalable prototype system allowing the continuous plasma treatment of flat wood panels as well as all the associated know-how in terms of conditions for the treatment of various wood species depending on the sought effect. Indeed, adjusting the conditions of the treatment, DURAWOOD can either increase the wettability of wood surface (enhanced durability of water borne coating) or make it more hydrophobic (temporary water repellence, increased compatibility with solvent based coating as an extra effect derived by the project and of interest for the industry but not a primary target). DURAWOOD also has some extent of biocide effect on fungi initially present in wood and may increase the efficiency of water borne wood preservatives.
The main scientific and technical elements of foreground consist in:
- The process parameters for treating wood with the DURAWOOD system: This foreground consists in the set of specific conditions for the treatment of various wood species depending on the sought effect. Indeed, adjusting the conditions of the treatment, DURAWOOD can either increase the wettability of wood surface (enhanced durability of water borne coating) or make it more hydrophobic (temporary water repellence, increased compatibility with solvent-based coating). Other related trade secrets such as the effect of the choice of different gas mixtures, or of the nature of coating systems combined are also included in this exploitable foreground. This 'library' of conditions results from over 10 000 experiments performed in STUBA.
- The design of the DURAWOOD plasma equipment to treat wood surface: this foreground consists in the design of the equipment to allow continuous treatment of wood surface in different conditions and in the selection of suitable electrodes. Indeed the DURAWOOD prototype allowed to treat the wood surface semi-continuously in a suitable way to integrate easily in wood factories as opposed to prior art whereby the treatments were made statically. As such, the prototype integrates 2 plasma electrodes and allows the treatment of up to 30 m2 of wood per hour after sanding as a pretreatment before coating. It is adjustable to the treatment of wood panels of different sizes up to 40-centimetre width, 2-metre length and 10-centimetre thickness. It has really low energy consumption in the range of 1 KW and can operate with several gases including the cost effective solution of simply using air or for example with a CO2 flow of less than 10 L / min.
- The formulation of water borne coatings with improved resistance to weathering: this foreground consists in the formulations of water borne coatings with better resistance to weathering that PAMAK formulated in the margin of the project. Based on the characterisations made in STUBA with and without plasma pretreatment, the best compositions in terms of polymeric matrix, ultraviolet stabilisers such as nanoparticles, hindered amine light stabilisers (HALS) were identified. Coating manufacturers in the consortium will continue improving their water borne coating products as well as specific solutions that showed most promising results in combination with the DURAWOOD treatment to reply to the market trends and especially to comply with the legislation EC 2004/42/EC.
Potential impact:
The main technical and economic strengths of the DURAWOOD technology that will drive its impact in the context of existing wood treatments are as follows:
- DURAWOOD will be versatile and adjustable depending on the application where it is used and type of wood to treat. Indeed, adjusting the conditions of the treatment, DURAWOOD can either increase the wettability of wood surface (enhanced durability of water borne coating) or make it more hydrophobic (increased compatibility with solvent-based coating, temporary water repellence).
- The DURAWOOD system is easily scalable by increasing the number of electrodes allowing continuous plasma treatment of flat wood panels at variable speed. Currently the prototype can treat in the range of 30 squares meters of wood per hour, at variable speeds, wood panel sizes up to 40 cm in width, 2 m in length and 10 cm in thickness. The interface is customisable to the needs of the used and is compliant for WiFi remote control.
- The DURAWOOD process will be easily integrated into existing wood facilities after sanding and before coating the wood. The possibility of performing wood pretreatment on site will be a key improvement, compared to the currently outsourced pressure and thermal wood pretreatments.
- From on-site visits and in-depth consultations, it has been further reinforced that wood manufacturers are not satisfied with current wood pretreatment techniques, which are expensive and need to be outsourced. In addition, classical (e.g. thermal and pressure) wood treatment techniques present many drawbacks: energy inefficiency, harmful to the environment (CO2 emissions), etc.
- The cost of DURAWOOD is lower than the current pretreatments, which are expensive. Indeed, the prototype allows treating up to 20 - 35 m2 per hour with an operative cost (related to a limited energy consumption) lower than 0.5 - 1 ct per m2 or approximately 11 ct per hour using air as atmosphere (to minimise ozone generation in comparison with when CO2 is used as atmosphere while maintaining an efficient treatment). For such system, the initial investment is estimated in the range of EUR 25 000 (with a potential future reduction once the used electrodes will be industrially available). Operation with CO2 requires a flow of less than 10 L / min and is therefore slightly more expensive but in general not justified technically.
The cost of competitive technologies is much higher. Indeed, the operative cost of pressure and thermal treatments is in the range of 50 ct - 1 EUR per m2 with an initial investment of EUR 500 000 - 1 000 000. These figures predict a fast return on investment for DURAWOOD system. Findings from the industry questionnaire-based survey and the industry consultations have revealed a willingness to invest in such a system in view of tangible technical and envisaged economic benefits.
- Additional economic assets could result from the hints that DURAWOOD could decrease the amount of fungicides needed and that DURAWOOD would decrease the frequency of maintenance of wooden articles used outdoors, an advantage to the general public.
- Uptake of DURAWOOD will be driven by legislative pressure to decrease the use of solvent borne coatings, in that the DURAWOOD solution will improve the durability of waterborne coatings and make them more competitive with solvent-based ones.
- DURAWOOD will assist European wood manufacturers to differentiate themselves through quality and sustainability and to compensate for the currently observed decrease in the use of sawn wood and increase in the use of wood particle panels, other materials and imports.
- The number of patents reviewed, along with an analysis of new technologies/products that have appeared in the marketplace in recent years, have confirmed significant interest in the market to improve current coating systems for protecting wood against weathering and fungi. However, to date none of the currently available solutions will offer the technological innovations or performance of DURAWOOD.
The main socio-economic and environmental impacts of the DURAWOOD material and process can be summarised as follows:
- As a really important environmental need for Europe and beyond, providing effective alternatives to solvent borne coatings is a hot topic. Associated VOCs pose a number of human health risks to respiratory function, particularly among workers in the coating industry but also among users. Public concern about the environment has led to the creation of regulatory programs to reduce air pollution, increasing the pressure on wood manufacturers to reduce harmful emissions derived from chemical treatments (VOC) and thermal treatments (CO2). As such, the European legislation (EC Directive 2004/42/EC) on coating products is fuelling a shift away from them towards waterborne coatings. This impacts the coating industry and its users.
- A clear need has been identified in the industry to improve the performance of water-borne coatings and to enhance wood protection against fungi attack while decreasing the required amount of fungicides. Water-based biocides for wood outdoors are mainly based on boron compounds, copper chromate boron salts; fluoric chromate boron salts and copper compounds free of chromium, which are harmful both for the environment and health and increase the price of treated wood.
- Final consumers of outdoor wooden articles, such as wooden facades may choose DURAWOOD pretreated wood coated with water borne system due to environmental concerns regarding the type of coating. However as well as this, consumers will also benefit from the reduced maintenance costs due to extended durability that seems to be predicted by increase adhesion during accelerated ageing experiments and would require field experiments over years for final validation. In addition, by extending the lifespan of wood products, DURAWOOD should allow keeping wooden materials in service for longer, thus minimising the problems associated with the disposal of the timbers. Wood products treated with DURAWOOD will be suitable for energy production by combustion, composting or for use as a secondary fibre source by related industries, without presenting any of the problems associated with residual chemicals from conventional coating systems.
Main dissemination and exploitation activities:
The economic aspects and the technical benefits of the DURAWOOD technology for the wood industry, by achieving for example similar adhesion for water borne coating as for solvent based counterparts, have served as basis for the dissemination and exploitation activities. As previously mentioned DURAWOOD is expected to have a significant impact on the wood industry, which is demanding of such improvements to fulfil the European Union (EU) regulations regarding volatile organic compounds, and will therefore also have a direct positive effect of the environment.
A great importance was given to the management of the intellectual property rights generated and in agreement of the dissemination of non-confidential information throughout the project. A patent review was carried out and concluded that DURAWOOD does not infringe upon existing protected intellectual property (IP). In addition, the project developed significant know-how in terms of treatment conditions that will be exploitable by the SMEs. In addition, the DURAWOOD trademark has been registered by PLASTECH which is taking a leading role towards the future commercialisation of the DURAWOOD system.
The wood market in which DURAWOOD will be introduced is a highly promising one, following an upward trend towards more sustainable solutions, especially in terms of coatings. The foreground generated by the DURAWOOD project is broad giving rise to the potential exploitation opportunities for each member of the consortium. A preliminary business plan and well as post project development work needed to reach full commercialisation have been laid out. The synergistic role of the partners covering the whole supply and value chain have been discussed as follows: the wood producers can help ensure the push to the market, due to their strong desire to enhance wood durability and make it more competitive with other materials, the plasma equipment manufacturer is opening themselves to new markets and the coating manufacturers are helping ensure the pull to the market by recommending DURAWOOD pretreatment for improving the performance of waterborne coatings.
Finally, successful dissemination activities have been carried out on the results and principles of the DURAWOOD technology through the project website and number of other activities raising the awareness of DURAWOOD both in industry and in the public domain and generating positive feedback. The results obtained in the DURAWOOD project have been promoted in an active dissemination strategy covering a broad range of media: over 24 disseminations were realised on TV, industry journals, web, conferences and trade fairs.
Contact details for further information:
Dr Ing. Elodie Bugnicourt
IRIS Innovació i Recerca Industrial i Sostenible, Spain
ebugnicourt@iris.cat
List of websites: http://www.DURAWOOD.eu
Wood used in outdoor applications is particularly susceptible to fungi and weathering leading to an insufficient durability especially when using water borne coatings. The DURAWOOD project developed a tailored plasma-based system for treating wood surfaces in continuous conditions suitable for industrial wood manufacturing. Tests conducted for different wood species showed that plasma can have different effects (temporary water repellence, improved wettability by different types of coatings resulting in improved adhesion, etc.). Therefore, in selected conditions, this pretreatment allows improving the quality of wood coated with waterborne coatings and helps wood processors to meet the European legislation by reducing volatile organic compounds (VOCs) emitted while using solvent based coatings (EC Directive 2004/42/EC).
Laboratory research conducted during the project showed that plasma can be used to modify wood surfaces in a fine tuned and versatile way. Upon performing over 10 000 experiments by varying the parameters of the plasma (various atmospheres, powers, treatment times, gaps, etc.), the conditions to make wood surface more hydrophilic or more hydrophobic were determined for different species at the laboratory scale. In addition, the effect of plasma was investigated by atomic force microscope (AFM) and infrared (IR) spectroscopy showing that a layer of hundred nm was modified on the wood surface. Polymerase chain reaction (PCR) methods were optimised to detect wood-decaying fungi. Methodology was also established for blue stain fungi according to well established standards. The tests of the efficiency of DURAWOOD in enhancing resistance against fungi were performed on many of the previous treatment conditions at the lab scale but also on the large wood panels treated in pre-industrial conditions. Tests indicated a large variability depending on the conditions of application of the plasma pretreatment and indeed of the coating and wood species. Therefore, experiments were performed on pre-inoculated wood samples showing a significant sterilisation effect of plasma in hydrophilisation conditions. The results were compared with simple experiments with ozone and UV treatments showing a much more efficient antifungal effect for DURAWOOD.
The lab set-up for plasma treatment was scaled up in order to treat the wood surface semi-continuously in a suitable way to integrate easily in wood factories. As such, the prototype integrates 2 plasma electrodes and allows the treatment of up to 30 m2 of wood per hour after sanding as a pretreatment before coating. It is adjustable to the treatment of wood panels of different sizes up to 40-centimetre width, 2-metre length and 10-centimetre thickness. It has really low energy consumption in the range of 1 KW and can operate with several gases including the cost-effective solution of simply using air or for example with a carbon dioxide (CO2) flow of less than 10 L / min.
The validation of the use of the prototype for pre-treating wood took place at the facilities of the project industrial partners in Slovakia and in Spain. The assessment of the quality of the resulting coated wood with and without plasma pretreatment was then carried out. This allowed confirming at large scale that the prototype still allowed a sufficiently fine gap regulation to lead to a significant change of the polarity of the wood both towards hydrophilisation and hydrophobisation depending on the desired effect, i.e. either to improve compatibility with respectively water borne coatings, or with solvent based coating (as an extra effect derived by the project and of interest for the industry but not a primary target) and temporary water repellence with solvent borne coatings. Therefore, adhesion tests and long term durability tests in terms of wood weathering were performed showing a positive effect of plasma in certain conditions and for selected wood specie and coating systems used in the different wood factories.
After this validation period, the DURAWOOD prototype was used during 2 demonstration sessions to industry.
Project context and objectives:
Wooden surfaces need to be durable in order to be attractive to customers and compete with other materials. Biological, physical and chemical pretreatments are generally applied to wood to improve its resistance to fungi causing decay and staining, its dimensional stability and its slightly increased equilibrium moisture content. But these classical wood treatment techniques present many drawbacks, such as energy inefficiency, and damage to the environment. In recent years, public concern about the environment has led to the creation of regulatory programmes to reduce air pollution, increasing the pressure on wood manufacturers to reduce harmful emissions derived from both chemical treatments (VOC) and thermal treatments (CO2). European legislation (EC Directive 2004/42/EC) on coating products is fuelling a shift away from the aforementioned towards waterborne coatings. However, wooden surfaces treated with waterborne coatings are more susceptible to discoloration and damage by wood-destructible and blue stain fungi. This situation presents serious challenges to the European wood processing industry.
Wettability is an important aspect of wood that influences its adhesive and coating quality. Wood has a relatively polar surface that allows the general use of waterborne coatings, however wood surfaces exposed to high temperature treatments are harder to wet. By producing high frequency electric discharges, plasma generates ionised gas that can modify the surface properties of the material it is in contact with. Plasma treatment is a versatile and powerful technique commonly used in many industries to activate the surface of materials such as plastics, textiles, glass and metals. However, before the DURAWOOD project, the use of plasma to treat wood has been limited to academic research.
Although low-pressure plasma processes have been studied for treating wood, atmospheric pressure processes are typically more attractive for wood industry applications because of their lower cost, higher throughput, and ability to operate in-line without vacuum systems. Atmospheric pressure plasma systems are typically based on volume dielectric barrier discharge (DBD) arrangement, where the treated material is placed between the discharge electrodes or the material itself works as one electrode. However, this arrangement is problematic for the treatment of thick wood materials where the process is highly energy intensive (due to resistive power losses) and as such, a high voltage is needed, leading to safety concerns. A more practical approach to solve the issue of power loss in the bulk of wood material, as pursued in the DURAWOOD project, is to use a planar plasma electrode, such as the diffuse coplanar surface barrier discharge (DCSBD). Due to the planar geometry of the discharge electrode, the electrical current and the discharge plasma are confined into a thin layer above the DCSBD electrode, presenting a high volume power density and thus generating a high concentration of reactive species.
In this context, the objective of this project centred on the development of a new industrial process (DURAWOOD) based on the application of plasma DCSBD to improve the coating adhesion of wood and therefore increase its durability, especially when using water borne coatings.
First, the participating small and medium-sized enterprises (SMEs), as well as a representative sample of European wood processors were consulted and results used to determine their needs and specifications and define the industrial specifications for the DURAWOOD prototype. This bottom-up approach ensured that the prototype which would be tested and validated in a real industrial environment, would meet not only the technological requirements of industry, but socio-economic requirements.
Second, laboratory research was carried out in order to validate the effectiveness of plasma technology for improving the wettability and waterproofing effects on wood surfaces. The aim was to generate highly hydrophobic wood surfaces as showed by significant contact angles increase, increase the wettability of the wood surface in order to increase coating adhesion and strength to ensure that wood treated with the DURAWOOD system developed during the project would require lower maintenance frequency. Positive results were observed with optimised plasma treatment conditions and selected coating systems. Then, an associated objective was to analyse the microbiological sensitivity of plasma treated and untreated wood to ensure that DURAWOOD treated wood offers at least the same resistance to attack from fungi and moulds when compared to woods treated with solvent-based coatings. To this end during this project traditional microbiological analyses were carried out, along with molecular analysis using the PCR method for analysing the presence of a selected number of moulds and fungi. The results were really dependent on the type of wood and conditions of the treatment.
Finally, the project aimed to design and build a pre-industrial prototype of the DURAWOOD system keeping with the previously defined specifications outlined and based on the laboratory set up. The aim was to deliver a DURAWOOD system that would be quick to apply, cost effective, deliver consistent product quality and constant treatment rates, capable of being easily and readily integrated into modern wood processing plants and of minimal environment impact. Then this prototype could be installed, tested and validated in a real industrial environment in the facilities of the wood manufacturers in the consortium. A further goal was to carry out demonstration activities proving the viability of the DURAWOOD system, outline its potential economic and environmental advantages. The overriding goal of this project was to ensure that the pre-competitive DURAWOOD prototype would fulfil the threshold requirements of the industry to ensure its further development post-project into a fully industrial system that would be taken to market, where its beneficial ecological impact could be felt at European level. This was also empowered by the realisation of dissemination activities throughout the project and the layout of an exploitation strategy by the consortium.
Project results:
The DURAWOOD project delivered a versatile, adjustable, scalable prototype system allowing the continuous plasma treatment of flat wood panels as well as all the associated know-how in terms of conditions for the treatment of various wood species depending on the sought effect. Indeed, adjusting the conditions of the treatment, DURAWOOD can either increase the wettability of wood surface (enhanced durability of water borne coating) or make it more hydrophobic (temporary water repellence, increased compatibility with solvent based coating as an extra effect derived by the project and of interest for the industry but not a primary target). DURAWOOD also has some extent of biocide effect on fungi initially present in wood and may increase the efficiency of water borne wood preservatives.
The main scientific and technical elements of foreground consist in:
- The process parameters for treating wood with the DURAWOOD system: This foreground consists in the set of specific conditions for the treatment of various wood species depending on the sought effect. Indeed, adjusting the conditions of the treatment, DURAWOOD can either increase the wettability of wood surface (enhanced durability of water borne coating) or make it more hydrophobic (temporary water repellence, increased compatibility with solvent-based coating). Other related trade secrets such as the effect of the choice of different gas mixtures, or of the nature of coating systems combined are also included in this exploitable foreground. This 'library' of conditions results from over 10 000 experiments performed in STUBA.
- The design of the DURAWOOD plasma equipment to treat wood surface: this foreground consists in the design of the equipment to allow continuous treatment of wood surface in different conditions and in the selection of suitable electrodes. Indeed the DURAWOOD prototype allowed to treat the wood surface semi-continuously in a suitable way to integrate easily in wood factories as opposed to prior art whereby the treatments were made statically. As such, the prototype integrates 2 plasma electrodes and allows the treatment of up to 30 m2 of wood per hour after sanding as a pretreatment before coating. It is adjustable to the treatment of wood panels of different sizes up to 40-centimetre width, 2-metre length and 10-centimetre thickness. It has really low energy consumption in the range of 1 KW and can operate with several gases including the cost effective solution of simply using air or for example with a CO2 flow of less than 10 L / min.
- The formulation of water borne coatings with improved resistance to weathering: this foreground consists in the formulations of water borne coatings with better resistance to weathering that PAMAK formulated in the margin of the project. Based on the characterisations made in STUBA with and without plasma pretreatment, the best compositions in terms of polymeric matrix, ultraviolet stabilisers such as nanoparticles, hindered amine light stabilisers (HALS) were identified. Coating manufacturers in the consortium will continue improving their water borne coating products as well as specific solutions that showed most promising results in combination with the DURAWOOD treatment to reply to the market trends and especially to comply with the legislation EC 2004/42/EC.
Potential impact:
The main technical and economic strengths of the DURAWOOD technology that will drive its impact in the context of existing wood treatments are as follows:
- DURAWOOD will be versatile and adjustable depending on the application where it is used and type of wood to treat. Indeed, adjusting the conditions of the treatment, DURAWOOD can either increase the wettability of wood surface (enhanced durability of water borne coating) or make it more hydrophobic (increased compatibility with solvent-based coating, temporary water repellence).
- The DURAWOOD system is easily scalable by increasing the number of electrodes allowing continuous plasma treatment of flat wood panels at variable speed. Currently the prototype can treat in the range of 30 squares meters of wood per hour, at variable speeds, wood panel sizes up to 40 cm in width, 2 m in length and 10 cm in thickness. The interface is customisable to the needs of the used and is compliant for WiFi remote control.
- The DURAWOOD process will be easily integrated into existing wood facilities after sanding and before coating the wood. The possibility of performing wood pretreatment on site will be a key improvement, compared to the currently outsourced pressure and thermal wood pretreatments.
- From on-site visits and in-depth consultations, it has been further reinforced that wood manufacturers are not satisfied with current wood pretreatment techniques, which are expensive and need to be outsourced. In addition, classical (e.g. thermal and pressure) wood treatment techniques present many drawbacks: energy inefficiency, harmful to the environment (CO2 emissions), etc.
- The cost of DURAWOOD is lower than the current pretreatments, which are expensive. Indeed, the prototype allows treating up to 20 - 35 m2 per hour with an operative cost (related to a limited energy consumption) lower than 0.5 - 1 ct per m2 or approximately 11 ct per hour using air as atmosphere (to minimise ozone generation in comparison with when CO2 is used as atmosphere while maintaining an efficient treatment). For such system, the initial investment is estimated in the range of EUR 25 000 (with a potential future reduction once the used electrodes will be industrially available). Operation with CO2 requires a flow of less than 10 L / min and is therefore slightly more expensive but in general not justified technically.
The cost of competitive technologies is much higher. Indeed, the operative cost of pressure and thermal treatments is in the range of 50 ct - 1 EUR per m2 with an initial investment of EUR 500 000 - 1 000 000. These figures predict a fast return on investment for DURAWOOD system. Findings from the industry questionnaire-based survey and the industry consultations have revealed a willingness to invest in such a system in view of tangible technical and envisaged economic benefits.
- Additional economic assets could result from the hints that DURAWOOD could decrease the amount of fungicides needed and that DURAWOOD would decrease the frequency of maintenance of wooden articles used outdoors, an advantage to the general public.
- Uptake of DURAWOOD will be driven by legislative pressure to decrease the use of solvent borne coatings, in that the DURAWOOD solution will improve the durability of waterborne coatings and make them more competitive with solvent-based ones.
- DURAWOOD will assist European wood manufacturers to differentiate themselves through quality and sustainability and to compensate for the currently observed decrease in the use of sawn wood and increase in the use of wood particle panels, other materials and imports.
- The number of patents reviewed, along with an analysis of new technologies/products that have appeared in the marketplace in recent years, have confirmed significant interest in the market to improve current coating systems for protecting wood against weathering and fungi. However, to date none of the currently available solutions will offer the technological innovations or performance of DURAWOOD.
The main socio-economic and environmental impacts of the DURAWOOD material and process can be summarised as follows:
- As a really important environmental need for Europe and beyond, providing effective alternatives to solvent borne coatings is a hot topic. Associated VOCs pose a number of human health risks to respiratory function, particularly among workers in the coating industry but also among users. Public concern about the environment has led to the creation of regulatory programs to reduce air pollution, increasing the pressure on wood manufacturers to reduce harmful emissions derived from chemical treatments (VOC) and thermal treatments (CO2). As such, the European legislation (EC Directive 2004/42/EC) on coating products is fuelling a shift away from them towards waterborne coatings. This impacts the coating industry and its users.
- A clear need has been identified in the industry to improve the performance of water-borne coatings and to enhance wood protection against fungi attack while decreasing the required amount of fungicides. Water-based biocides for wood outdoors are mainly based on boron compounds, copper chromate boron salts; fluoric chromate boron salts and copper compounds free of chromium, which are harmful both for the environment and health and increase the price of treated wood.
- Final consumers of outdoor wooden articles, such as wooden facades may choose DURAWOOD pretreated wood coated with water borne system due to environmental concerns regarding the type of coating. However as well as this, consumers will also benefit from the reduced maintenance costs due to extended durability that seems to be predicted by increase adhesion during accelerated ageing experiments and would require field experiments over years for final validation. In addition, by extending the lifespan of wood products, DURAWOOD should allow keeping wooden materials in service for longer, thus minimising the problems associated with the disposal of the timbers. Wood products treated with DURAWOOD will be suitable for energy production by combustion, composting or for use as a secondary fibre source by related industries, without presenting any of the problems associated with residual chemicals from conventional coating systems.
Main dissemination and exploitation activities:
The economic aspects and the technical benefits of the DURAWOOD technology for the wood industry, by achieving for example similar adhesion for water borne coating as for solvent based counterparts, have served as basis for the dissemination and exploitation activities. As previously mentioned DURAWOOD is expected to have a significant impact on the wood industry, which is demanding of such improvements to fulfil the European Union (EU) regulations regarding volatile organic compounds, and will therefore also have a direct positive effect of the environment.
A great importance was given to the management of the intellectual property rights generated and in agreement of the dissemination of non-confidential information throughout the project. A patent review was carried out and concluded that DURAWOOD does not infringe upon existing protected intellectual property (IP). In addition, the project developed significant know-how in terms of treatment conditions that will be exploitable by the SMEs. In addition, the DURAWOOD trademark has been registered by PLASTECH which is taking a leading role towards the future commercialisation of the DURAWOOD system.
The wood market in which DURAWOOD will be introduced is a highly promising one, following an upward trend towards more sustainable solutions, especially in terms of coatings. The foreground generated by the DURAWOOD project is broad giving rise to the potential exploitation opportunities for each member of the consortium. A preliminary business plan and well as post project development work needed to reach full commercialisation have been laid out. The synergistic role of the partners covering the whole supply and value chain have been discussed as follows: the wood producers can help ensure the push to the market, due to their strong desire to enhance wood durability and make it more competitive with other materials, the plasma equipment manufacturer is opening themselves to new markets and the coating manufacturers are helping ensure the pull to the market by recommending DURAWOOD pretreatment for improving the performance of waterborne coatings.
Finally, successful dissemination activities have been carried out on the results and principles of the DURAWOOD technology through the project website and number of other activities raising the awareness of DURAWOOD both in industry and in the public domain and generating positive feedback. The results obtained in the DURAWOOD project have been promoted in an active dissemination strategy covering a broad range of media: over 24 disseminations were realised on TV, industry journals, web, conferences and trade fairs.
Contact details for further information:
Dr Ing. Elodie Bugnicourt
IRIS Innovació i Recerca Industrial i Sostenible, Spain
ebugnicourt@iris.cat
List of websites: http://www.DURAWOOD.eu
