• Journal of the Korean Wood Science and Technology
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• v.40 no.3
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• pp.212-227
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• 2012

Current research trends in wood preservatives for enhancing durability was reviewed. Due to leaching of recent Copper-Based Preservatives commonly used as chemicals for pressure treatment; they have been a growing concern, especially in improving the fixation of the copper as alkyl ammonium quat. and azol in wood and preventing the leaching of active ingredients. With the appearance of emulsion type chemicals using micronized and nano-sized wood preservatives, researchs on characteristics of Copper-Based Preservatives regarding penetration and fixation in wood are debatable. Moreover, unlike the case of CCA, the recent alkyl ammonium quat. and azol bear a serious threat in the decrease of antimicrobial effectiveness against wood destroying fungi with copper tolerance. Therefore, development and research of co-biocide is needed.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.544-558
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• 2017

The objective of this research is to investigate preservative efficacy for refractory species in field tests. The field tests were set up to evaluate the preservative performance of western hemlock and white spruce preservative-treated to the residential products group C and D of Canadian standard (CSA O80 Series-08) that have been developed for residential use in above-ground and ground-contact conditions, respectively. They were incised and pressure-treated with alkaline copper quaternary (ACQ) or copper azole (CA). Treated samples for the ground contact stake test and ground proximity test were installed in Jinju, Korea on November 2010 according to AWPA E7-09 and AWPA E18-06, respectively. Each sample has been annually assigned ratings for decay and termite attack, based on AWPA E7 grading system. After six years and five months of exposure, the untreated samples showed decay and particularly severe damage by termite attack but all the preservative-treated samples showed no decay. The results showed that the 5-mm penetration depths may be applicable for the treatment of refractory species. This paper discusses what to consider for the use of refractory species in Korean wood preservation industry from the penetration and retention points of view.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.641-651
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• 2015

The aim of this study was to estimate the service life of alkaline copper quaternary (ACQ)-treated wood. The service life of preservative-treated wood was estimated by comparing a residual quantity of ACQ in wood with toxic threshold to fungi. Indoor and outdoor leaching tests were carried out in order to predict residual ACQ quantity within wood. As a result, the leaching ratio of ACQ from treated wood above ground via precipitation was 18.1% for 50 years. When the H4 treated wood, which is traditionally used in contact with the ground and fresh water, is used above-ground, the leaching ratio of ACQ for 50 years is 18.1% and the residual quantity of ACQ is $4.2kg/m^3$, which is higher than the toxic threshold of ACQ. Thus, the H4 treated wood used above-ground will be resistant to biodeterioration for at least 50 years.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.245-254
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• 2009

As a substitute for CCA, which is inhibited due to its environmental pollution and human harmfulness, and CuAz and ACQ with a high cost, okara-based wood preservatives were formulated with okara hydrolyzates using copper sulfate and/or borax as a metal salt. The efficacy of the preservatives and X-ray microanalysis of wood specimens treated with the preservatives were examined to confirm the potential of the okara-based wood preservatives. Most of the preservatives showed excellent decay resistance against brown-rot fungi, Postia placenta and Gloeophyllum trabeum. The efficacy was improved when the acid concentration and temperature used for the hydrolysis of okara increased. In addition, when borax was added into copper sulfate/okara hydrolyzates preservative formulations, any decay was not found in the specimens. From the microscopic observation of the specimens treated with okara-based wood preservatives, it seems that okara is contributed to the fixing of metal salts in wood blocks. Therefore, it is speculated that okara-based wood preservatives can effectively protect wood against fungal attack as CuAz, and that the preservatives are sufficient to use as an alternative wood preservative of CCA, ACQ and CuAz.

• Journal of the Korean Wood Science and Technology
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• v.23 no.3
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• pp.66-72
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• 1995

The rate of fixation of the components were evaluated in CCA-Type B and CCFZ-treated radiata pine sapwood by quantitative analysis of solution expressed from the treated wood. The leaching characteristics of radiata pine blocks treated with CCA-Type B and CCFZ were also evaluated by the AWPA standard leaching test. Both fixation and leaching charactersistics of CCA-Type B were compared with CCA-Type C treated wood samples. The rate of CCA-Type B fixation was a little faster than that of CCFZ. However, significant amounts of arsenic was unfixed in the CCA-Type B treated samples and consequently leached. These significant quantities of arsenic liberated from the CCA-Type B treated wood during service may pose some environmental concerns. Arsenic was no longer detectable from CCA-Type C treated samples when fixation was complete, even though the fixation of CCA-Type C was slower in some degree than CCA-Type B. In summary, it could be said that CCFZ was much safer preservative than CCA-Type B by the criterion based on the relative hazard assessed by absolute amount of unfixed element present in the treated wood. Also the decision that CCA preservative has to move from Type B to Type C should be made sooner or later for continuous use of CCA preservative in the future.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.187-200
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• 2013

Current research trends of non-copper wood preservatives for enhancing durability was reviewed; as a follow-up of the review in 2012 on copper-based wood preservatives. Main environmental friendly non-copper wood preservatives studied by many scientists were boron-based compounds, synthetic compounds from natural products, and pyrethroids family of chemicals, etc. The critical issue regarding treated woods with boron-based compounds used outdoors was the leaching of boron. Many studies mainly focused on boron fixation improvement using variety of polymers. Moreover, the studies showed notable increases in attempts to use natural products used commonly in the medical fields as wood preservatives as well as outdoor use of chemical modified such as acetylated wood developed in purpose of stabilizing dimension.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.87-94
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• 2005

This study was carried out to investigate the effect of soil types and soil properties on wood preservative leaching. Radiata pine (Pinus radiata Don.) sapwood stakes, which had been treated with 2.0%(w/v) CCA, were leached for 12 weeks by a common laboratory method in four different soils and for 14 days by the AWPA standard leaching method in water. The physical and chemical properties of the four soils were determined, and the percent leaching of the individual component of CCA was correlated with the various soil properties. The data show that leaching of preservative chemicals from treated wood exposed to soil is influenced by the type of soil. The preservative leaching was greater when wood was exposed to water than when the wood was in contact with water-saturated soil. The greatest chromium, copper and arsenic leaching from CCA-treated stakes were observed in the sandy loam, loam, and sand, respectively, and the least amount of leaching of CCA components occurred in the silty loam. The leaching of preservative components from treated wood is extremely complex and appears to be influenced differently by the soil properties. The extent of copper leaching from CCA treated wood appears to be related to exchangeable Mg and sum of bases. There is a reasonably good relationship between chromium leaching and exchangeable Mg, and between arsenic leaching and exchangeable K, soil Ni, Mn, Fe, Cr, or Cu content. Since this study was conducted based on laboratory leaching method using small cross-sectional dimensions; thus, data obtained from this experiment should not be used to predict leaching characteristics from commercial-size wood used in real situation. Accordingly, further studies are necessary using outdoor ground-contact leaching.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.110-123
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• 2008

The use of CCA as a wood preservative was recently inhibited due to its environmental pollution and human harmfulness. Instead of CCA, copper azole (CuAz) and alkaline copper quaternary (ACQ) have been used as alternative wood preservatives, but the price of the preservatives is much more expensive than that of CCA. As a substitute for high-priced CuAz and ACQ, environmentally friendly wood preservatives were formulated with okara, which is an organic waste from the production of tofu. Prior to formulating the preservatives, okara was hydrolyzed by three levels of sulfuric acid concentration (1, 2.5 and 5%) to easily penetrate the effective components of the preservatives into wood blocks. Final preservative solutions were formulated with the hydrolyzed okara and metal salts, such as copper sulfate, copper chloride and borax. The preservatives were treated into wood blocks by vacuum-pressure method to measure the treatability of the preservatives, and the treated wood blocks were placed in hot water for three days to measure the leachability of the preservatives. The effective components of the preservatives might be successfully penetrated into wood blocks through the uses of hydrolyzed okara and ammonia water. However, the leached amount of effective components was increased as the concentration of acid used for the hydrolysis of okara increased. The treatability and leachability of the preservatives were not affected by hydrolysis temperature but negatively affected by the addition of borax. Based on the results above, the optimal conditions for formulating okara-based wood preservatives cost-effectively and environmentally might be 1% acid hydrolysis of okara and the use of $CuCl_2$ as a metal salt. In addition, the treatability and leachability of okara-based wood preservatives were superior or no differences comparing with those of CuAz. Therefore, it is concluded that okara-based wood preservatives might have a potential to be used as an environmentally friendly wood preservative.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.810-817
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• 2015

This study was conducted to evaluate the pressure treatment characteristics of yellow poplar skin timber with ACQ-2, CUAZ-3, and CuHDO-1. The effect of moisture content (MC) on treatability was investigated, and fixation characteristics of copper-based preservatives were also evaluated. Sapwood of yellow poplar, which was dried below 50 percent MC, was fully penetrated with preservatives, and minimum requirement of preservative retention for the hazard class H3 was achieved. Through measuring retention gradient in yellow poplar sapwood, it was confirmed that minimum requirement of preservative retention for the hazard class H3 was achieved in the assay zone from the surface to 15 mm-depth when the specimens were dried below 30 percent MC. Yellow poplar heartwood did not meet the minimum requirement of penetration and retention for the hazard class H3 over the range of pretreatment MCs tested. The fixation rate of copper was much faster under drying condition compared with nondrying condition; more than 90% of copper were fixed in 3 weeks at $21^{\circ}C$ under drying conditions.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.716-725
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• 2016

In this study, MCQ (Micronized copper Quat) which was copper-based wood preservative, was investigated on decay properties by difference of the its infiltration volume. After pressure-treatment with different MCQ concentration, test specimens (Japanese Red Pine) were exposed by a brown-rot fungus (Fomitopsis palustris). At the end of the 12 weeks exposure to the fungus, untreated specimen was showed the mass loss of more than 35%, and the value of preservative effectiveness of MCQ by indoor decay was $3.99{\pm}0.42kg/m^3$. Therefore, MCQ should be pressure-injected at least $3.99kg/m^3$. The three dimensional of the specimens were observed by using the light microscope and scanning electron microscope, Untreated and treatment specimens with low concentration generally had underwent serious decays and had a lot of fungal hyphae. Howere, the formation of bore hole by hyphae were not observed. Mass loss and decay properties of specimens were affected by amount of MCQ injection. Therefore, it is necessary to the review of the adequacy of the MCQ injection amount in domestic environments.