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Algal growth resistance of paints for coating of wood; a laboratory study
1997 - IRG/WP 97-10213
Twelve paints were tested for resistance against algae. In addition, one algicidal compound commercially used for remedial treatments of algal growth on paints was tested for its effectiveness for prevention of algal growth. An agar diffusion bioassay was employed in which paint films on filter paper discs were placed on mineral salt medium and sprayed with an algal suspension containing a mixture of one blue-green alga, Oscillatoria tenuis, and two green algae, Ankistrodesmus gracilis and Pleurococcus sp. Most growth was recorded in plates with discs painted with acrylic paints. Two acrylic paints containing a commercial fungicide at normal or double concentration permitted the same amount of growth as the same acrylic paint without fungicide addition. The solvent-borne alkyd paints and the alkyd emulsion paints were more inhibitory against growth of algae. Only some of the acrylic paints permitted any growth of the green alga Ankistrodesmus gracilis. Acrylic paints containing a commercial algicide inhibited the growth of the Pleurococcus sp. and Ankistrodesmus gracilis but permitted some growth of Oscillatoria on the agar medium used.
J Bjurman

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

The resistance of wood coated with different water-borne paints against colonisation by decay fungi
1996 - IRG/WP 96-10165
The susceptibility of wood painted with model paints of known composition to decay fungi was tested without previous weathering. Included in the study were five alkyd emulsion paints and five acrylic paints; one linseed oil paint and two solvent-borne alkyd paints. It was found that several components influenced the susceptibility of these paints. The results of the present study indicate that the particle size of latex paints, the pigment volume concentration and the amount and type of surfactant in the water-borne paints are critical for colonisation by decay fungi of painted wood. An anion surfactant was somewhat fungicidal. The results are briefly discussed in relation to major paint components and to available knowledge of the properties of water-borne coatings on wooden substrates. The present study is part of a larger project aiming at improvement of the durability of painted wood.
J Bjurman

Optimized composition of alkyd emulsion with nanoparticles of iron oxide for enhancing protection of thermally modified wood
2022 - IRG/WP 22-40940
Thermal treatment is acknowledged as an environmentally friendly method to improve durability of wood and some of its properties, such as biological resistance, dimensional stability, reduced hygroscopy. Despite these improvements, when used outdoors, also thermally treated wood is subjected to the action of environmental factors, like solar radiation, moisture, precipitations, temperature, etc., giving place to a series of chemical and structural transformations, defined as “weathering”, which negatively affect its service life. In this research an alkyd emulsion containing red transparent iron oxide pigments was obtained, whose composition is optimized to protect the decorative properties of thermally treated wood during outdoor exposure. In particular, attention was dedicated to the selection of surfactants for the emulsification of resins and to the investigation of oxidative properties of alternative metal primary driers, which could replace the cobalt. Initially the surface wetting properties of thermally treated wood were investigated and considered for the optimization of the alkyd emulsion formulation. The determination of the surface energy of wood, by means of contact angle, before and after thermal treatment shows that the polar component of the surface energy decreases with increasing temperature of thermal treatment. This explains the more hydrophobic character of thermally treated wood, which must be considered for the formulation of suitable paints and the selection of appropriate additives. In the second part of the research, artificial weathering test was carried out to determine the suitable concentration of red transparent iron oxide pigments, which can give better protection against photodegradation and minimize the color changes of wood surface. The obtained results show that a concentration of 8 % for red transparent iron oxide pigments in alkyd emulsion is necessary to ensure protection of the thermally treated wood surface. Another important conclusion from the obtained results is that the replacement of organic solvent with water is possible and paint with comparable or even better efficiency can be obtained.
E Sansonetti, D Cīrule, I Andersone, B Andersons, E Kuka

Finishes for outdoor timbers
1975 - IRG/WP 378

Principles and procedure of the planeing test
1981 - IRG/WP 2162
Small end-sealed samples of pine-sapwood (1.5 x 2.5 x 5 cm³) are treated by brushing and afterwards different parts of the treated surface are removed. The remaining part of the sample is tested against either insects or fungi. If no attack occurs sufficient amounts of biocides have been penetrated at least beyond the zone which has been removed. In spite of some problems the test seems the only suitable method, to evaluate organic solvent preservatives, mainly those containing resins, for simple treating methods.
H Willeitner, M Gersonde

Effect of a penta emulsion on the service life of Douglas fir, heartwood posts
1978 - IRG/WP 3112
C S Walters

Analysis of organotin fungicides in wood preservative solutions and double-vacuum treated wood
1983 - IRG/WP 3250
A new analytical method using high-performance thin-layer chromatography (HPTLC), for the assay of organotin compounds in preservative-treated wood, is presented. The organotin compounds are extracted from the ground wood sample with a mixture of hydrochloric acid and ethanol. After HPTLC-separation, exposure of the thin-layer plate to ultraviolet light, and dipping of the plate into a 0.1% pyrocatechol-violet solution, the different organotin compounds are quantitated using a scanning densitometer.
W Hintze, S V Ohlsson

Wood preservation in the Australian beekeeping industry
1988 - IRG/WP 3473
This paper reports the results of a survey of Australian commercial beekeepers working 200 or more hives in June/July 1985. Nine hundred and forty seven apiarists were asked to participate and to provide information on their wood preservation methods, painting procedures and maintenance of bee boxes. Three hundred and eighty-four apiarists returned completed questionnaires (41%). The main wood preservatives used are copper naphthenate solutions (45%), linseed oil (8%), copper chromated arsenate (3%), hot wax (9%), copper naphthenate solution in linseed oil (3%), linseed oil/wax mixtures (3%) and paint (23%). The majority of apiarists (96%) paint treated bee hives, but there is considerable variation in wood preservative treatment procedures and paint application. Most wood preservative treatments (95%) are of the 'do-it-yourself' variety, radiata pine being the most utilized timber. The bottom boards of bee hives are considered the most susceptible to wood decay and subterranean termite damage, as are cleats, stands or any wood in ground contact.
P J Robinson, J R J French

Thirty-four year test of on-site preservative treatments to control decay in wood above ground
1993 - IRG/WP 93-30015
This research was initiated in 1958 to investigate efficacy of various preservatives and treating methods for new lumber going into exterior structures of buildings. Post-rail units (2x4 inches) constructed of Southern Pine sapwood, Douglas-fir heartwood, and mill run western hemlock were dip- or brush-treated before or after assembly. Units were trested with pentachlorophenol in various petroleum solvents or with copper napthenate in mineral spirits. Both painted and unpainted units were exposed on a test fence in Madison, WI. Most of the painted untreated pine units (controls) failed by 34 years. Surprisingly, painting completely protected the untreated Douglas-fir units from decay and afforded substantial protection to untreated hemlock. Significant decay in painted units was present only in lightly treated pine units (2-second dip after assembly or brush treated). Copper napthenate (1% copper) was markedly less effective than the penta treatments on unpainted pine and hemlock units. There was no evidence that type of oil carrier or incorporation of a water repellent improved effectiveness of treatment. Three or 15-minute dips in penta were equally effective. Penta-grease applied to unit ends only was effective.
T L Highley, T C Scheffer

Bibliography: Interactions of wood preservatives with wood, metals, glues, paints and concretes
1983 - IRG/WP 3271
H Becker

Surface coatings for impregnated wood
1992 - IRG/WP 92-3684
The use of proper surface coatings enhances the aesthetic and protective properties of impregnated wood. Good results with especially water-borne coatings have been obtained for class-A impregnated L-joints and claddings in field tests started in 1982.
L Kotama

Resistance of painted pine sapwood to mould fungi. Part 1. The effect of waterborne paints and fungicides on mould growth
1997 - IRG/WP 97-10233
The efficacy of different fungicides in acrylate and alkyd paints to protect pine sapwood against mould fungi was studied. The acrylate and alkyd paint systems with and without a preservative dipping treatment prior to painting were also used. Differences in the efficacy of the fungicides to protect the paint film were found. The paint films with isothiazolon and IBPC were resistant against mould fungi but the paint films with propiconazole were susceptible to mould. The mixture of propiconazole and IPBC or propiconazole and isothiazolon performed well even at a low concentration. The dipping treatment alone and some fungicides in the paint films supported even higher mould growth than was observed on untreated wood. The most effective combinations were free from mould growth after 26 weeks at RH 100%. In future, the effect of 26 weeks' natural weathering on mould growth will be assessed and the results of the mould test and natural weathering will be compared. The study is a part of a project CT94-2463 in the AIR programme of DG XII.
H Viitanen, P Ahola

Penetration of deltamethrin in micro-emulsion formulation after injection in wood
1996 - IRG/WP 96-40068
In the Netherlands (and some other European Countries) the remedial treatment of death watch beetle is still a problem. This is because the larvae of this insect penetrate the central heartwood of mainly large oak beams. The heartwood is difficult to treat. The preventive treatment of wood boring insects has only recently been permitted in the Netherlands. Since 1989 injection of insecticides is recommended by the Dutch Association of Pest Control Companies (in Dutch this is the NVO for short, and member of CEPA). New methods of treatment are expected from the use of water-dilutable insecticides, for example deltamethrin in a micro-emulsion formulation. At this moment, this deltamethrin micro-emulsion is the only water-dilutable insecticide for use on wood with a registration in the Netherlands. TNO has measured the difference in penetration after injection of wooden beams of both deltamethrin in organic solution and deltamethrin in the water-soluble micro-emulsion. This work was part of a government project to study potential reduction in emission of organic volatiles (KWS 2000, see IRG/WP 94-20030). Results on European oak show a better penetration of deltamethrin from the micro-emulsion formulation compared with the organic solvent formulation. Better results were obtained from high pressure injection than low pressure. Results indicate that most redistribution of deltamethrin occured shortly after injection. From these results, the number of injection points for remedial treatment of death watch beetle in oak can be reduced by using deltamethrin in a micro-emulsion.
P Esser, W L D Suitela

Protecting wooden structures
1980 - IRG/WP 392
Chromium-containing chemicals that effectively retard weathering of wood improve performance of subsequently applied finishes. Current work is focusing on the performance of wood-derived products (plywood, hardboard, fiberboard, particle board) after surface treatment with inorganic chemicals. The overall objective of the continuing research is to investigate new environmentally safe procedures to stabilize wood surfaces and to improve performance of applied finishes.
W C Feist

Waterborne silicones as wood preservatives
1995 - IRG/WP 95-30062
For more than thirty years silicones are used as water repellents for masonry. Their excellent properties make them also attractive for non-mineral substrates like wood. Although it was always thought that silicones are not able to perform on wood, a new type of aqueous silicone materials proofed the opposite: Excellent water repellency and astonishing durability were achieved. This paper describes the nature of these products, the background of their performance and the test results on wood.
R Hager

The resistance of wood coated with different solvent-borne paints against colonisation by decay fungi
2009 - IRG/WP 09-40468
This paper examines different solvent-borne paints characteristics and their decay resistance when applied on pine wood surface. It was determined by the standard ENV 839 procedure. The part of samples were subjected to accelerated ageing according to the EN 84 standard. The discussed commercial paint systems were typical stains or penetrating oil-based products, with or without biocides.
B Mazela, P Hochmańska

Moisture condition in treated wood exposed outdoors. A progress report
1989 - IRG/WP 3533
Wood treated with water-borne preservatives, mainly CCA (copper/chromium/arsenic), CCB (copper/chrome/boron) or CC (copper/chrome) is often said among users in Sweden to absorb more water than untreated wood. In laboratory tests this statement has not been confirmed but no field tests have been carried out in Sweden to study this phenomenon. In 1986 a project was started to compare water absorption during outdoor exposure between wood stakes of pine (Pinus sylvestris) and spruce (Picea abies) both untreated and treated with different preservatives. For comparison stakes of different species were included as well as painted pine stakes. Equilibrium moisture content in humid environment was tested for untreated pine-stakes and stakes treated with CCA and ammoniacal copper preservatives.
M-L Edlund, C E Sundman

Effect of soil parameters on biocide depletion: laboratory and field studies of water- and emulsion-borne preservatives
2000 - IRG/WP 00-30234
Two field test sites with different soils were selected. Soil analysis showed that the soil at the two sites had considerable texture, base saturation, acidity, and cation exchange capacity differences. Five sets of field stakes were treated as follows: three with water-borne CCA to about 0.4 pcf (6.4 kgm-3) retention, one with 0.75% DDAC, and one with 0.75% DDAC:0.25% chlorothalonil. The last two sets were treated using oil-in-water emulsions. Samples from all five sets were installed at both field sites. In addition, wood samples which had been co-treated with the five sets of field stakes were installed in a lab environment in fungus cellar tubs using soils from the two sites. All wood samples were defect-free southern yellow pine (SYP) sapwood, with the field stakes measuring 19 x 19 x 457 mm3 and the fungus cellar samples measuring 5 x 19 x 250 mm3. The field samples were exposed for two or three years and the fungus cellar samples for 36 weeks, after which depletion of the various biocides was measured. No consistent pattern in CCA depletions between the two soils were observed in either the fungus cellar or field exposure tests, despite the large chemical and physical differences between the two soils. The fungus cellar method may be useful to conduct relatively rapid depletion studies. The authors also discuss problems with depletion studies, including possible influences by soil, wood, and microorganisms present in the soil.
T Schultz, D D Nicholas, D E Pettry, M G Kim

Development of a turbidity method for the determination of water repellent in CCA treatment solutions
2000 - IRG/WP 00-40177
The use of aqueous water repellent emulsion formulations has increased significantly in the wood treatment industry. These are primarily used to enhance the weathering characteristics of wood products treated with water borne preservatives systems used in exterior above ground exposures. However, they are also used in pole treatments to improve the climbing characteristics and in low VOC millwork treatments. With the increase in water repellent treated wood production there was a requirement to develop analytical methods for the determination of the water repellent concentration in treatment solutions for quality control at wood treatment facilities. Various methods were examined for the determination of water repellent emulsions in wood treatment solutions. Of the methods considered the turbidity method was found the best suited for routine quality control at treated wood production facilities. The effects of emulsion concentration and particle size on the turbidity measurements were evaluated.
P J Walcheski, L Jin

Evaluating the performance of preservative/water repellent emulsion systems
1997 - IRG/WP 97-20127
Water repellent emulsions are being combined with wood preservatives to improve the weathering properties of treated wood in service. Unfortunately, few standard procedures are available to objectively compare the performance of these systems and as a result quality issues are almost completely neglected. The value of swellometer tests, water immersion tests and accelerated weathering regimes in the understanding of water repellent performance is discussed. This paper represents a step towards the development of water repellent standards which will serve to protect both the interests of the consumer and the wood treating industry.
K J Archer, F Cui

A preliminary assessment of the penetration into wood achieved by bodied mayonnaise emulsion wood preservatives
1992 - IRG/WP 92-3725
Five different commercial formulations of bodied mayonnaise emulsions were applied to samples of Scots pine (Pinus sylvestris) sapwood as recommended by the manufacturers. Penetration and loading characteristics were determined by measuring the distribution profiles of the active ingredients after various intervals of time. The changes in the general appearance of the emulsions on the surface of the treated wood was also observed. It was concluded that the nature of the formulation can affect the speed and extent of penetration of the active ingredients into the timber and that the simple expedient of applying more emulsion to the surface of the wood does not necessarily lead to increases in penetration and loading. Application of bodied mayonnaise preparations appears a reasonable option for the remedial treatment of insect attack, particularly where spot treatment is adequate. However, treatment against wood-destroying fungi may not provide sufficient protection in the longer term where the risk of attack is relatively high. It is recommended that further work be carried out to confirm the findings of this limited study.
G E Holland, R J Orsler

Blue Stain Testing of Alkyd and Acrylic Stains
2003 - IRG/WP 03-20273
Resistance against blue stain of semi-transparent alkyd and acrylic stains was tested by both EN 152 and the so-called reverse exposure test methods. Comparison of the results, obtained by both methods was the most important aim of this study. As expected, performance of the water-borne acrylic paint was lower compared to protective effectiveness of the alkyd stain. This difference was even more pronounced when artificially accelerated aged samples were exposed. It seems that the reverse exposure method may give more distinctive results. In general, our results confirm previous literature reports on adequacy of the reverse test method for evaluation of blue stain resistance of surface finishes.
M Petric, M Pavlic, B Kricej, M Humar, F Pohleven

Penetration of surface applied deltamethrin micro-emulsion formulations in four European timber species
1994 - IRG/WP 94-20030
The Netherland's Government, in line with many other European Governments initiated a programme (KWS2000) aimed at significantly reducing the emission of volatile organic compounds by the year 2000. As part of this programme a research project is currently underway to evaluate the potential for replacing organic solvent based remedial treatments with micro-emulsion formulations of the same or enhanced insecticidal activity. To date the project has evaluated the penetration of a deltamethrin micro-emulsion formulation in four species, notably, Scots pine (Pinus sylvestris) sapwood and heartwood, Norway spruce (Picea abies) heartwood, Douglas fir (Pseudotsuga menziesii) heartwood and European oak (Quercus petraea) heartwood. The test method used, an adapted version of the German standard DIN 52 162, subsequent a.i. distribution analyses and results are discussed.
P Esser, W L D Suitela, A J Pendlebury

Analysis of water repellents in wood treated with water borne formulations using FTIR
2000 - IRG/WP 00-40176
The use of aqueous water repellent emulsion formulations has increased significantly in the wood treatment industry. These products are primarily used to enhance the weathering characteristics of wood products treated with water borne preservatives systems used in exterior above ground applications. They are also used in pole treatments to improve climbing characteristics and in low VOC millwork treatments. With the increasing usage of such products. there has been a need to develop analytical methods for the determination of the water repellent in treated wood products to ensure product quality and to aid in the development of enhanced water repellent formulations. A method for the determination of the water repellent concentration in wood was developed using Fourier transform infrared spectroscopy (FTIR). The wood samples were extracted and prepared for the FTIR scans using a liquid cell. The water repellent concentration was determined by using the intensity of the hydrocarbon C-H stretch adsorption. Methods for correcting or eliminating the interference from non-water repellent components in the wood extracts were developed.
P J Walcheski, L Jin

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