TANNIN BARK

Greymouth Evening Star, 29 August 1934, Page 3

TANNIN BARK

’ POSSIBLE WEST COAST INDUSTRY The chairman (Cr. F. A. Kitchingham) of the committee recently set up by the Greymouth Borough Council, in connection with endeavours to promote new industries on tyre West Coast, has received the . following letter from Dr. E. Marsden, secretary of the Department of Scientific and Industrial Research: —“While in Reefton recently, I happened to see an issue of the ‘Greymouth Evening Star’ for Friday, August 10, and noted the suggestions of your committee regarding tannin bark. I enclose for your information notes prepared by our leather research chemist.” The notes referred to are as follow: The amount of tannin material consumed in New Zealand is comparatively small, consequently the future of any industry, whether producingbark or extract, will depend entirely on prices ruling outside'the Dominion. The prices of tannin materials. in the world’s markets is probably dominated by the price of quelbracho extract, produced in South America. Owing to cut-throat competition and depreciated currency, the price of this extract is about £l2/10/ (sterling) per ton, C.I.F. Liverpool. This low price has brought down the price of all other tanning materials, e.g., the price of South African ground wattle bark was quoted at the same time at £6/5/(sterling) C.1.F., United Kingdom ports. These prices allow little return to the producer, unless cheap labour and cheap raw materials are available. To produce one ton of extract, the amount of bark necessary would be from 21 tons to 5 tons, according to the quality. If an export trade is desired, then, in order to reduce the cost of freight, as ground bark is very bulky, concentrated extracts must be produced. A plant of this type, to produce 10 tons of solid extract per day, would probably cost £14,000 (sterling). It is a very difficult proposition to introduce a .new tanning material, because the tanner does not know the type and quality of leather it will produce. On account of the slow nature of the tanning process, it will take from 6 to 12 months to obtain the necessary information as to how to use the new material to the best advantage and to obtain tests on the leather produced. With regard to the production of ground bark, the Kamahi tree seems the best of the indigenous trees for this purpose. So long as the tannin content is approximately 30 per cent., it should be possible to replace some, if not all, the ground wattle-bark at present being used. Extensive experiments will be necessary before this can. be carried out. There seems no reason why this should not be done and this would provide a, fairly large amount of labour, as little capital would be involved. The demand for the bark at first would be small until each tanner had satisfied himself on the points mentioned previously. 7'he processes involved in the production of ground bark are as follow: (a) Stripping of the bark (generally carried out as the sap is rising). (b) Drying the bark. (c) Grinding and bagging. Possibly on the West Coast, drying sheds might be necessary, but, during .Summer, sufficient natural drying

might be obtained, without recourse to artificial drying. The bark from the Tanekaha tree has been examined. In the past, large quantities of this bark have been used commercially, especially for the manufacture of gloving leathers. The bark contains a large amount of material — dye material—and the bark can only be used economically, if advantage is taken of this, i.e., the bark is used for dyeing as well as tanning leather. The dye is a very undesirable feature for ordinary tanning processes, where colour is not required. As no cheap method of removing this colour has yet been found, the development of Tanekaha bark does not seem possible. The present position appears to be: (1) Owing to the low values of tanning materials on the world’s markets, which will not always exist, there seems to be little prospect of any immediate successful trading in New Zealand tanning materials. (2) Large scale tests over six or twelve months might develop a local demand for a ground bark. (3) Where suitable barks are a byproduct of the milling industry and are regarded as of no value, then there is the possibility of an extract plant being rriade a commercial success.