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Albumin borate: A new non-toxic, wide-spectrum, long-term wood preservative
1998 - IRG/WP 98-30167
Boron, widely recognized for its broad range of activity towards both fungi and insects and for its low mammalian toxicity, can not provide long term protection to treated timber due to its high leachability. Boron, in the form of boric acid, can be partially fixed to timber by the formation of an association with egg albumin, which is insolubilized by heat-induced coagulation. Chemical investigations on fixation mechanisms of boric acid by egg albumin indicated that both acid-base salt formation occurs, as well as the formation of boric acid-albumin complexes, depending on the boric acid/protein ratio. In treated timber, a chance in protein conformation in presence of boric acid, has been shown by scanning electron microscopy. These mechanisms, partly reversible, while greatly retarding its leaching, leave small amounts of boron free to exercice its activity when needed. Boron leaching as a function of time, appears to tend to an equilibrium value, which one differs in the case of an albumin coagulum alone from what is obtained by leaching treated wood samples. Accelerated biolocical tests using such treated timber have shown that albumin borate used as wood preservative has effectiveness against wood decay, and have durability performances comparable to those obtained with CCA.
M-F Thévenon, A Pizzi, J-P Haluk


Comparative investigations on the influence of wood seasoning, wood properties and temperature on the toxic values of wood preservatives against Hylotrupes egg larvae
1970 - IRG/WP 28
Comparative tests carried out at three institutes indicated the influence of kiln temperature, position of wood specimens in the cross sectional area and test temperature on the toxic values determined in accordance with DIN 52165 with egg larvae of the house longhorn beetle (Hylotrupes bajulus L.). The preservatives applied were boric acid in distilled water and g-benzene-hexachloride dissolved in chloroform; the timber species used was pine sapwood, (Pinus sylvestris L.). The method of seasoning had no influence on the toxic values of boric acid. With the g-BHC, however, the toxic values gradually increased with rising kiln temperatures (20°C, 70°C, 105°C). With boric acid the position of the sapwood samples in the log had no influence on the toxic efficacy; with g-BHC the efficacy was slightly greater in the outer sapwood, compared with the inner sapwood. The test temperatures (20°C, 24°C, 28°C) yielded different toxicity results for boric acid. At 24°C and 28°C the threshold values were somewhat below those of 20°C; they agreed with the values obtained at 20°C after a longer test period. With g-BHC different temperatures did not affect the results. An explanation is suggested for the causes of the influence exerted by the kiln temperature and wood properties on the toxic values of g-BHC. There was good agreement between the toxic values obtained in the different institutes.
G Becker, T Hof, O Wälchli


Some observations on Chlorophora pilosus Forst. var. glabromaculatus Goeze (Coleoptera, Cerambycidae)
1980 - IRG/WP 1119
A Gambetta


Comparative evaluation of the barrier effect against Hylotrupes bajulus L. of different types of wood preservative
1986 - IRG/WP 1307
This paper settles the difference of contact action against females of Hylotrupes bajulus the likelihood of egg-laying, the ovicide effect and the hazards of development of newly hatched larvae between some preservatives belonging to three differents types: mineral waterborne products, organic products and emulsions. The results show that against females, the action is fast with organic products, slower with emulsions and non existent with mineral products. They point out the relation between the longivity of females and the eventuality of egg-laying. With ageing, this latter become possible for almost every preservative. In the most of cases, the larvae hatch from eggs and can bore into wood until they accumulate the lethal dosis and that occurs more or less fastly. A few differences are observed for preservatives of the same category.
M-M Serment


Use of freeze disinfection for the control of the common furniture beetle Anobium punctatum
1992 - IRG/WP 92-1528
The common furniture beetle Anobium punctatum is an extremely widespread pest of wooden objects in Danish museums. In order to develop non-chemical methods of controlling the pests, experiments were conducted to elucidate the lower lethal temperature of Anobium punctatum. The egg stage was used for the experiments as it is considered the most temperature resistant stage. Groups of Anobium punctatum eggs were exposed to temperatures of -14, -18, -22, -26 and -30°C. Freezing durations were 8 hrs, 24 hrs and 48 hrs, respectively. Preliminary results of the experiments are presented.
L Stengård Hansen


Giftwirkung einiger organischer Zinn-Verbindungen auf Eilarven von Hylotrupes bajulus (L.). [Toxic efficacy of some organic tin compounds against egg larvae of Hylotrupes bajulus (L.)]
1978 - IRG/WP 2120
The toxic values of 12 organic tin compounds towards newly hatched larvae of Hylotrupes bajulus were determined after 4- and 12-week test periods in comparison with bis-tri-n-butyltin oxide (TBTO). Tri-n-butyltin benzoate as well as the 2-, 3- and 4-methyl benzoate of tributyltin oxide were equally effective as TBTO and the latter two were somewhat more effective after a 12-week test period. Almost the same effects were obtained with N-cyclohexyl-diazenium-dioxy tri-n-butyltin. Less effective than TBTO by about the factor 2 were the compounds hexa-n-butylditin, tripropyltin(2-methyl benzoate) and N-cyclohexyl-diazenium-dioxy-tripropyltin, by about the factor 3 the compounds 3-acetyl-6-methyl-1.2-pyrane-4-on-2-tributyltin oxylate, the respective triphenyl compound and tri-n-butyltin dibrome propionate, by about the factor 10 another compound. Not only the chemical constitution but also the tin contents have to be considered in the evaluation of the results.
G Becker


Current status of AAC preservatives in New Zealand
1980 - IRG/WP 3141
Two types of alkylammonium compounds (AAC) have been approved as commercially acceptable wood preservatives by the NZ Timber Preservation Authority (TPA). They are alkyldimethylbenzyl ammonium chloride and alkyldimethylamine acetate, both of which must contain either (a) 70% alkyl chains of C12 + C14 and less than 10% of any other individual chain length, or (b) 85% alkyl chains of C12 + C14 with no restriction on percentage occurrence of any other chain length. Existing approvals cover formulations of the quaternary ammonium compound and of the tertiary, amine salt. Approvals for use are currently restricted to Pinus radiata and to those commodities which do not involve ground contact. For interior building timbers (Commodity Specification C8), where protection is required only against insects, the minimum charge retentions and core loadings are: Alkyldimethylbenzyl ammonium chloride: 1.5 kg/m³ and 0.1% w/w; Alkyldimethylamine acetate: 1.0 kg/m³ and 0.07% w/w.
J A Butcher


The effects of accelerated drying of green Pinus radiata on its attractiveness to Anobium punctatum as an egg-laying site
1984 - IRG/WP 1199
The methods and results are given for a series of experiments in drying Pinus radiata sapwood under a variety of conditions, then exposing the material to Anobium punctatum egg-laying. The results showed very clearly that the attractiveness of the wood to gravid females was drastically reduced when dried from green at temperatures much above 35°C. Both simple oven drying and steam kilning produced the effect. Attempts to reverse the effect, or develop it in already seasoned wood, indicated that it was a phenomenon related to the green state, i.e. it could not be induced at any other time, and this in combination with special drying techniques results suggests that it is oxidative in character. On current evidence it seems unlikely that fungi/bacteria have a major role in the effect.
D J Cross