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End grain sealants for wood preservation studies
1985 - IRG/WP 3341
The results of tests with possible end grain sealants for wood preservation studies are reported. The epoxy resins used gave satisfactory performance on wet or dry Sitka spruce and have been used with success for diffusion treatment studies.
R J Murphy, N A Summers


Decay and termite resistance of wood treated with boron-containing quaternary ammonia compound, didecyl dimethyl ammonium tetrafluoroborate (DBF) incorporated with acryl-silicon type resin
2004 - IRG/WP 04-30334
This study evaluates the decay and termite resistance of surface-treated wood with didecyl dimethyl ammonium tetrafluoroborate (DBF) incorporated with acryl-silicon type resin emulsion. DBF is a quaternary ammonia compound and contains boric tetrafluoride (BF4-) as a counter ion in its chemical structure. In the study, DBF was incorporated with an acryl-silicon type resin to increase water-resistant of the preservative solution, and, in turn, to increase decay and termite resistance of surface-treated wood after severe weathering processes. Laboratory decay resistance tests were performed using brown-rot fungus Fomitopsis palustris and white-rot fungus, Trametes versicolor. Treated wood specimens were also subjected a 3-week-termite resistance tests using subterranean termites, Coptotermes formosanus. Wood specimens surface-treated with preservative solution including 2% DBF and the resin showed decay resistance against both F. palustris and T.versicolor even after severe weathering. Results suggested that treatment with DBF at 2% or greater concentrations containing acryl-silicon type resin emulsion would protect wood used outdoors against both fungal decay and termite attack.
S N Kartal, W J Hwang, K Shinoda, Y Imamura


Comparison of colour change in wood clear-coating systems including inorganic and organic UV absorbers for exterior use
2010 - IRG/WP 10-40499
The aim of this work is to compare the performance of inorganic and organic UV absorbers used in a wood coating application against weathering. Our study has investigated the colour changes of selected UV absorbers; hombitec 402 RM from the Sachtleben Company as an inorganic UV absorber, tinuvin 477 DW from the Ciba Company as an organic UV absorber. The study was carried out on two wood species; Fagus sylvatica L., Pinus sylvestris L. The results obtained after 28 days (672h) of accelerated weathering showed that the colour stability was the same for hombitec 402 RM and tinuvin 477 DW and both systems showed a significant improvement of colour stabilization compared to the control samples. In addition, the wood surface from cracks was protected with the clear-coat containing both of UV absorber.
Ö Özgenç, B Forsthuber, A Teischinger, C Hansmann


Effects of intumescent formulation of vinyl acetate-based coating on flame-retardancy of thin painted red lauan (Parashorea spp.) plywood
2011 - IRG/WP 10-40537
Using intumescent coatings on wood-based materials is an effective method for fire safety. The intumescent coatings consist of four major components: (1) binder resin (BR), (2) carbonizing substance (CS), (3) foam producing substance (FPS) and (4) dehydrating agent (DA). Previous studies have demonstrated that the formulation of the four components strongly influences the performance of coatings. This study investigated the effect of intumescent formulation of vinyl acetate-based coating on flame-retardancy of plywood. Two sorts of widely used binder resin (BR) for vinyl acetate-based coating, ethylene vinyl acetate copolymer (EVAc) and vinyl acetate acrylic copolymer (VAC), were used. The fire retardancy of coatings on plywood was assessed by a cone calorimeter. Total heat release and time to peak heat release rate are the two primary parameters. The data showed that lower BR and FPS content decreased total heat release and lengthen time to peak heat release rate. This mechanism to achieve better fire performance was verified by using oxygen bomb calorimeter and thermogravimetrical analysis, exhibiting lower heat of combustion and weight loss. The lower BR and FPS content can extend the survival duration of phosphor-carbonaceous chars. The results provide information for designing vinyl acetate-based coating.
Chih-Shen Chuang, Kuang-Chung Tsai, Te-Hsin Yang, Ming-Kuang Wang, Chun-Han Ko


The Comparison of Weathering Resistance of New Generation Wood-Coating Systems
2017 - IRG/WP 17-40789
In this study, the performance of wood-coating systems containing different UV absorbers was evaluated in artificial weathering conditions. Acrylic-based resin containing three different UV absorbers was applied on oriental beech and scots pine surfaces. Weathering conditions were sustained for 84 days. After the weathering test, the change of color and roughness on the wood surface was measured to determine the effectiveness of coating systems. The coating systems were found quite resistant against weathering conditions. The color changes of wood samples were lower compared to the beginning of the weathering test. Similarly, the changes in surface roughness values of wood samples showed that coating systems provide quite high preservation against weathering conditions.
Ö Özgenç, S Durmaz


Effects of acetylation on the dimensional stability and decay resistance of kenaf (Hibiscus cannabinus L.) fiberboard
1996 - IRG/WP 96-40059
The objective of this study was to investigate the influence of the acetylation treated kenaf fiber, Phenol formaldehyde resin content level, and three fungi species on the dimensional stability and decay resistance of high density non wood composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness, length changes, and decay resistance of the high density kenaf fiberboards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Rowell


Leaching of components from water-borne paints and fungitoxic effects
1995 - IRG/WP 95-20062
Water-borne model paints, acrylics and alkyd emulsion paints, of known composition were leached according to a procedure modified in accordance with ASTM 6271.1. The effectiveness of fungicidal compounds in the painted specimens before and after leaching was evaluated with a biotest in which Penicillium brevicompactum was used as a test fungus. The leaching of the fungicide Troysan Polyphase according to the biotest varied to a high extent depending on differences in paint composition. Fungicide efficiency in relation to paint formulation and fungicide mobility in a paint film is briefly discussed.
J Bjurman


Durability of larch (Larix spp.) wood against brown-rot fungi
1997 - IRG/WP 97-10228
Durability of the heartwood of Larix decidua, L. sibirica, L. gmelinii, L. gmelinii var japonica, L. gmelinii var olgensis and L. sibirica x decidua against brown rot fungi Coniophora puteana, Poria placenta and Gloeophyllum trabeum was tested according to EN 113 test method. Parallel samples were used to study the amount and composition of wood extractives. The sample trees originated from the research forest of Punkaharju Research Station. The average age of the trees was 60 years. In addition, from L. sibirica also trees at 25 and 102 years were used. Results show that the durability of larch is depending on species, age of the tree, the wood part (inner or outer heartwood) and fungus. The average durability of larch heartwood was equal to class 3 or 4 (moderately or slightly durable, according to the standard EN350:2) and comparable with the durability of pine heartwood (Pinus sylvestris L). However, the durability of L. gmelinii var olgensis and L. sibirica (102 years old) was on the higher level than that of the other studied species but the durability varied even within the same board. Also the durability of wood from L. sibirica grown in the Russian side (Siberia) was studied. It was equal to that of the trees grown in Finland. The average amount of resin acids of larch heartwood was only about 0.1% (dry weight). In contrast, the heartwood of scots pine may contain up to 4.0% of resin acids. Resin acids are found to inhibit the linear growth of certain fungi. Interestingly, the largest amounts of resin acids (0.3%) were found in the heartwood of L. gmelinii which also showed high durability. The concentration of water soluble extracts (mainly arabinogalactan) of larch heartwood was quite large, varying between 3.2 - 20.5%. The concentration of water soluble extracts in the heartwood increased along the age of the trees. Lowest level of extractives were found in Larix decidua which was also the least decay resistant species. The durability of wood in different targets and the role of different chemical compounds of larch heartwood on decay resistance needs to be clarified.
H Viitanen, L Paajanen, P Saranpää, P Viitaniemi


Some characteristics of Pinus radiata wood from trees subjected to resin extraction
1987 - IRG/WP 3403
35 year old Pinus radiata trees growing in La Puntilla (lat. 37° south, long. 72,4° west), Chile, were subjected to resin extraction 5 years ago. After harvesting them simultaneously with control trees of the same place and age, probes were taken from the bottom of each pole, at 3.4 m, 7.8 m and 11.4 m height. Analysis of ethanol/benzene extract, CCA salt penetration tests and sapstain and brown-rot development rate were performed. The extract content differed in both groups. In the ascendent sense it decreases in unextracted trees and increases in extracted. CCA salt penetration was deeper in treated trees than in untreated. Wood subjectect to resin extraction was less susceptible to sapstain development. No significant difference was detected in both groups in relation to the development of brown-rot.
M C Rose, J Navarrete, G Sandoval, A Bedoya, L Ortega, R Zurita


A novel method for delivering fluids into bolted wooden components.
2004 - IRG/WP 04-40280
The paper describes the development of a washer that enables fluids such as wood preservatives and adhesive resins to be delivered to bolted wooden components in-situ. The system was developed to meet the criteria of low cost and the ability to tolerate inaccurate drilling of holes in the wooden members.
G S Sawyer, B Tole


Control of death-watch beetle (Xestobium rufovillosum Deg.) with experimental permethrin smoke generators
1982 - IRG/WP 3199
This paper presents results obtaining by monitoring population figures, the condition and reproductive state of beetles collected at weekly intervals after each annual treatment.
S J Read


Scientific development for prolonging the service life of timbers by impregnating with creosote or organic solvent type preservatives in which additive has been incorporated
1977 - IRG/WP 382
Chemically impregnated wood has played a prominent part in the Telephone and Electricity Distribution Industry during the past century and there is no doubt that it will play an equally prominent part in the future. The reasons why wood poles and wooden, structures predominate, are that when adequately chemically impregnated with a recognised timber preservative to ensure the expected service life for the purpose envisaged, the timber is then fully protected against the ravages of wood destructive organisms. Furthermore, wood is endowed with many natural characteristics that make it a favourite pole and structural material. Its high strength, light weight, ability to absorb impact or shock from loads suddenly applied and ability to resist overloading for brief periods plus its well-known insulating qualities - all are important basic reasons for its predominance in pole line structure. The use of chemically impregnated timber often makes it possible to carry out a given construction programme at less cost, or to erect more structures for a given sum of money, than when more expensive construction materials are employed.
P R B D De Bruin


An investigation into the stability of TBTO in LOSP-treated radiata pine
1987 - IRG/WP 3459
Nuclear magnetic resonance (NMR) spectroscopy and reverse phase paper chromatography were used to characterise the organotin compounds found in radiata pine treated with bis (tri-n-butyl) tin oxide (TBTO). Preliminary results indicate that the preservative is remarkably unstable in wood after light organic solvent preservative (LOSP) treatment. Significant decomposition of TBTO occurs in a matter of hours. White crystalline material observed on the surface of treated wood was identified as tributyltin acetate (TBTA). Other tributyltin esters, dibutyltin ethers, and butyltin chlorides were also identified.
K J Archer, R Meder


Time dependent over-uptake of etherificated melamine resins
1998 - IRG/WP 98-40109
Waterbased methanol-etherificated melamine-formaldehyde resins can increase the fungal resistance of the treated wood though they are known to be non-toxic. Therefore melamine-resins are at the present an object of research activities of European projects and of some companies. The paper highlights the importance of quoting the duration of the diffusion when immersed in the treating solution, as major differences in the effectiveness against fungal attack can be obtained by extending the diffusion period. This paper also critically reviews the practice of referring the concentration of the solutions used for impregnation to a fixed solids content of this type of resins.
D Lukowsky, R-D Peek


The formation of organotin carboxylates in bis(tributyltin) oxide - treated Pinus sylvestris sapwood
1990 - IRG/WP 3618
Tributyltin compounds have been successfully used for many years as wood preservatives, although their chemical nature in timber have not been fully elucidated. This study by 119Sn and 13C NMR spectroscopy has shown that, on impregnation into Pinus sylvestris sapwood, bis(tributyltin) oxide, (Bu3Sn)2O, is rapidly converted to tributyltin carboxylates, Bu3SnOCO·R, via reaction with components of the wood resin. It is further suggested that the formation of these species is a prerequisite for the known disproportionation reaction which occurs in (Bu3Sn)2O - treated timber.
S J Blunden, R Hill


Decay resistance of resin treated wood
1999 - IRG/WP 99-30206
Selected natural resin systems were evaluated for their potential as wood protecting agents according to standard test procedures. As indicated by the European standard EN 599 both a Basidiomycete test according to EN 113 and a ENV 807 soil bed test were carried out. Six resin treatments were tested using 3 concentration or treatment levels. Using the biocidal activity criteria as usually applied for wood preservatives it became obvious that resin treatments do not comply to the standard requirements. None of the resin treatments tested allowed the establishment of toxic limits when all Basidiomycete fungi were considered. Four resin systems showed a clear impact of retention. The functional relationship of the percentage mass loss to the resin retention was examined. Based on this function the retention levels corresponding with specific mass loss levels were calculated for each fungus. Treatment levels are proposed taking into account the envisaged utilisation under European hazard class 3 (EN 335) and the mass loss criteria for wood species belonging to natural durability class 3.
J Van Acker, A J Nurmi, S M Gray, H Militz, C Hill, H Kokko, A O Rapp


Treatment of particleboard with isocyanate resin to impart improved dimensional stability and water repellency
2000 - IRG/WP 00-40178
Standard particleboard panels (for interior use) of 16 mm nominal thickness were cut into samples measuring 6.4 mm x 78 mm2. The samples were divided into 4 end matched batches. Two batches were treated with isocyanate resin and cured. The other 2 batches were left untreated. One of the treated batched and 1 of the untreated batches were edge sealed with epoxy resin prior to isocyanate resin application. The weight and thickness of each samples was measured prior to placing the sample in a beaker of distilled water. The weight and thickness were measured periodically for 1 week. Treatment with isocyanate resin reduced the average weight gain of sealed samples compared to the controls after 1 week. The average weight gain after 144 hours was 37% and 63% respectively while unsealed samples achieved a weight gain of 37% and 100% respectively. The thickness swelling was also reduced in the sealed samples compared to the controls (10% and 17% respectively) and the unsealed samples had a thickness swelling of 9% and 21% respectively. The results show a reduction in the rate of moisture uptake (water repellency) and amount (dimensional stability). Further experiments are described comparing particleboard with solid wood, with and without isocyanate resin application.
K M Filcock, P Vinden


Laboratory evaluation of phoxim in plywood
2001 - IRG/WP 01-30264
Two types of phoxim treated plywood bonded by phenolic resin glue and urea resin glue were challenged with termites of Coptotermes formosanus Shiraki in laboratory. It was found that the sawdust of phoxim treated plywood bonded by phenolic resin glue was not active or did not kill termites of Coptotermes formosanus Shiraki within the test period. Moreover, the phoxim treated plywood bonded by phenolic resin glue did not prevent damage from termite attack. At the end of the test period, the plywood mass loss rate was about 21.81%. The gas chromatography was used to estimate the degradation rate of phoxim in phenolic and urea resin glue and the recovery rate of phoxim in plywood bonded by phenolic and urea resin glue. The results of analysis indicated that 7.48% of phoxim in phenolic resin glue was recovered after aging 8 hrs, and only traces of phoxim in plywood which was treated with phoxim and bonded by phenolic resin glue were found.
Zhong Junhong, Lin Liling, Huang Hong


Dimensional stability, biological resistance, and mechanical properties of phenol-resin-treated particleboard
1990 - IRG/WP 3622
Particleboards were treated with a low molecular-weight phenol-formaldehyde (PF) resin and their enhanced properties were evaluated. Besides dipping of particles in aqeous solutions of resin, and spraying of resin solutions before spray of the conventional phenol-formaldehyde resin for adhesive binder, one step treatment by spraying of the mixture of the low molecular-weight resin and the adhesive resin was also employed. After 2-hour boiling, the boards treated at 10% incorporated resin loading (IRL) retained 80% of their strength values in a dry condition. The internal bond strength increased with increasing IRLs, and the boards of 20% IRL showed twice of the value of untreated controls in the same level of board density. Treated particleboards resulted in a more dramatic reduction in the rate of swelling even at low resin loadings. Results obtained from accelerated laboratory tests on biodegradation suggested that incorporated resin-solids worked well to enhance decay and termite resistance of particleboards.
Y Imamura, H Kajita


Biological resistance of phenol-resin treated wood
1990 - IRG/WP 3602
Biological resistance of PF (phenol formaldehyde resin) - treated wood has been tested in relation to the resin properties, wood species and biological factors. When tested using water-soluble PF (mol. wt. 170), ca. 10% RI (resin impregnation) was enough to suppress the decay of Japanese cedar (Cryptomeria japonica) and western hemlock (Tsuga heterophylla) blocks exposed to Tyromyces palustris (brown-rot type) and Coriolus versicolor (white-rot type). For a decay suppression of Japanese beech (Fagus crenata) by treating with the same PF, ca. 20% RI was required for both cases of exposure. When using ethanol-soluble PF (mol. wt. 300), the lesser effect on decay suppression was revealed for most of wood-fungus combinations, suggesting a possible better penetration of lower molecular resin into the wood cell walls. PF treatment of wood also affected the termite Coptotermes formosanus, causing the severe depletion of feeding activity and the higher mortality at 5-15 (%) RI. Of the three species of symbiotic protozoa, the most cellulolytic Pseudotrichonympha grassii diminished first shortly after feeding.
M Takahashi, Y Imamura


Resin bleed after light organic solvent preservative treatment - the effect of drying method and process type
1986 - IRG/WP 3378
The effects of drying method and treatment process type on resin bleed were investigated. High-temperature drying of resinous radiata pine (Pinus radiata D. Don) heartwood resulted in improved wood permeability, higher preservative uptake, and greater resin bleed when treated by the Rueping process. Resin bleed was reduced substantially when timber was treated by the Lowry process, and totally eliminated when Bethell-treated. The incorporation of 2% wax into the preservative formulation may control resin bleed after Rueping treatment.
P Vinden


Biodegradation of acetylated southern pine and aspen composition boards
1994 - IRG/WP 94-40020
This objective of this study was to investigate the influence of the acetylation treated wood fiber, Phenol-formaldehyde resin content level, two wood fiber species, three fungi species on the dimensional stability and decay resistence of high density composition boards. A standard ASTM method was used to evaluate weight loss and thickness change. The linear shrinkage and expansion of each species were also determined. All specimens were exposed to decay chambers for 16 weeks. Test results indicated that most of the main factors significantly influence the thickness and length changes and the decay resistance of the high density composition boards.
P Chow, T Harp, R Meimban, J A Youngquist, R M Powell


Testing method for the treatability of wood
1994 - IRG/WP 94-40031
In order to test and classify the treatability of wood species in pressure treatment processes with water-based solutions, a laboratory method was developed which allows the testing of small samples and limited sections of a stem, e.g. sapwood. The penetration of different liquids was determined separately concerning the three anatomical directions of wood. The common parameters for pressure impregnation were used on sap- and heartwood of eight indigenous and tropical wood species. An elastic epoxy resin proved feasible for coating the samples on five sides. From the data of the testing method a measure for the treatability was calculated, allowing to classify wood species into four treatability classes analogous to prEN 350-2 (1993).
A O Rapp, R-D Peek


Evaluation of the fire retardant efficacy and leach resistance of an amino resin fire retardant - Preliminary report
1983 - IRG/WP 3260
The Early Fire Hazard Indices of untreated Pinus radiata were determined by testing to Australian Standard 1530, Part 3 - 1976. Differences in the performance of heartwood and sapwood were noted, with heartwood samples giving higher Ignitability, Heat Evolved and Spread of Flame indices. The treatability of Pinus radiata with Pyrogard H was assessed, and backsawn sapwood treated more effectively than all other combinations of direction of cut and sapwood/heartwood. Treatment of kiln dried DAR Pinus radiata with Pyrogard H did not produce dimensional changes of practical significance. This factor, plus a high concentration gradient of retardant in the treated timber, make it an ideal treatment for fully machined and profiled Pinus radiata. The leach resistance of the retardant was assessed. A greater percentage of phosphorus than nitrogen was leached, but the retardant remaining after leaching conferred similar protection to the unleached material at equivalent rententions. Pyrogard H is an effective leach resistant fire retardant for Pinus radiata.
W D Gardner, P N Alexiou, P Lind, D Butler


EELS (Electron Energy Loss Spectroscopy) - a technique for quantification of nitrogen and other light elements in the cell wall
1999 - IRG/WP 99-20163
A literature survey was performed to find progress in techniques for monitoring penetration of synthetic resins in wood cell walls. Electron energy loss spectroscopy (EELS) in combination with transmission electron microscopy (TEM) was successfully applied for the high resolution examination of the distribution of a partly methylated hydroxymethyl melamine resin in Norway spruce (Picea abies Karst.) earlywood cell walls. The nitrogen of the resin was found as clearly detectable signals in all layers of the lignified cell wall, thus allowing the quantification of resin which had penetrated into the different layers.
A O Rapp, H Bestgen, W Adam, R-D Peek


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