PAPER FROM TREES

Dominion, Volume 21, Issue 260, 3 August 1928, Page 18

PAPER FROM TREES

USE OF NEW ZEALAND WOODS

TESTS IN UNITED STATES SUCCESSFUL EXPERIMENTS An interesting interim report has teen issued on the pulp and paper tests upon New Zealand woods, recently supervised in North America by Mr. A. It. Entrican, engineer of the New Zealand State Forest Service. The report shows that commercial grades of newsprint may be produced from' insignis pine and tawa, and of .kraft papers (i.e., wrappings, etc.) from rimu, insignis pine, and a number of other woods. Other classes of paper, such as book, fine printings, etc., may also be manufactured from some of these woods, but since they are consumed in comparatively small quantities they do not command the same attention as do newsprints and wrappings, which lead all papers in quantities used. I Purpose of Tests. 1 Thirty years ago the Government Initiated a tree-planting programme .which has gained momentum steadily, ■until to-day the Forest Service has planted some 136,000 acres, and expects to establish this 1028 planting season ~ a further 63.000 acres. The Forest Service is administering, too, a forest domain of over seven million acres. AU these plantations ‘and forests are yielding large volumes of wood, for which it is necessary to develop profitable markets. Some of the forest crop, goes into building and constructional timber, some into poles and fencing posts, and some into fuel wood. Yet there still rpmains material in the shape cither of mill waste, or of unused species, or of •wopds and thinnings and improvement cuttings, for which no outlet has appeared available, largely because we did not know how or for what purpose to use them. •An intensive study of the situation indicated that the most promising avenue for the utilisation of much of the material lay in the pulp and paper industry, and the Government decided accordingly that it should first ascertain if the principal woods were suitable for • this purpose. Most unexpectedly, the Government of the United States of America was found to be interested in some of the problems involved in the work, and the Forest Service entered into an agreement whereby the Forest Products Laboratory at Madison, Wisconsin, the foremost pulp and paper research institution of its kind in the world, undertook to study the pulping and papermaking properties of a number of our woods. Mr. Alex. 11. Entrican was deputed *to assist with the work and to make an; industrial survey, of the pulp and paper business in North America. Laboratory and Mill Tests. The laboratory tests initiated at Madison eventually proved so successful that the Government decided to carry the study to a logical conclusion by extending its scope to include a mill scale test under commercial operating conditions. This included a pulping and papermaking trial at the Ladysmith<Wisconsin) plant of the Great Western Paper Company.' i ■ Woods Tested. Of the woods studied, two species arc Indigenous to New Zealand: Rimu (Dacirydium cupressinum), a softwood; and tawa (Beilschmiedia tawa), a hardwood; arid four introduced softwoods, insignis pine (Pinus radiata), Austrian pine (Pinus austriaca), Corsican pine (Pinus iaricio), and European larch (Lurix europea). The two native species, rimu and tawa, and the introduced softwood, insignis pine, were studied more intensively than the others, the rimu because 'it is the most widely distributed and commonly used softwood in New Zealand, and the insignis pine, since it is the most widely propagated species in the extensive man-made forests . established by Government and private interests. The tawa was studied not only as the principal hardwood of the North Island forests, but as being typical of a group of hardwoods —they all have the same type of fibre—such as blue gum (Eucalyptus globulus). and Tasmanian stringybark (E. obliqua). The three remaining woods—Austrian and Corsican pine and European larch —are some of the minor species included in the Forest Service plantations. Other. species included in the Government and private “forestation efforts are Douglas fir (Pseudotsuga Douglasii) and western yellow pine (Pinus ponderosa), but in view of the previous studies on these Woods made by the Madison Forest Products Laboratory, further work was considered unnecessary. I Three Main Objectives. The methods of wood pulp manufacture fare described in detail in the report. In planning the pulping tests, three major objectives were set up, their importance being considered in the order named: . To produce a pulp or pulps suit- , able for newsprint. 2. To produce a satisfactory kraft pulp, for wrappings, etc. , i 3. T° produce bleached chemical pulps for fine papers. '■ In pursuance of the first objective, pulping., tests were made by' means of ithe mechanical, sulphite, and combined mechanical-chemical processes, the greater part.of the work being devoted to insignis pine and tawa as the most suitable species available. Rimu, larch, and all of the pines, were pulped by the sulphate process, in order to evaluate their possible utility for kraft papers. Pulping tests by the soda process were limited to tawa. Bleached chemical pulps were produced from insignis pine sulphite and and sulphate pulps, and from tawa sulphite and soda pulps. i Grouiiflwood Pulping Trials. ' In general, groundwood pulps from infeignis pipe were found , equal to spruce in yield 'and strength, but inferior from the standpoint of colour and dirt. Being a hardwood and very short fibred, the tawa yielded a pulp much inferior in strength to both insignis pine “and spruce. The tawa yield per cord was about 10 per cent, higher than in the case of spruce.) The rimu was found too dark, and the larch and other pines too patchy to yield a, satisfactory grade of groundwood. ’ Sulphite Pulping Trials. \ - Unbleached sulphite constitutes from 20 to 30 per cent, of the average news-' print paper, and in line with the major objective of the study, the principal effort in the sulphite pulping experiments was directed towards the production of a grade of pulp suitable for newsprint. Only three woods —rimu. tawa, and insignis pine—were successfully reduced by this process. The experiments with rimu indicated that this species can be readily reduced to pulp by the sulphite method, bu tth. eproduct is too dark for use in newsprint unbleached. Insignis pine was reduced to a suitable quantity of pulp for use in newsprint paper without bleaching, the yields and strength quality being comparable with those of sulphite pulp from white spruce. Although the

Jjulp produced at the laboratory was inferior in colour to spruce pulp, that manufactured at the Ladysmith pulp 1 mill almost equalled the commercial grades of spruce sulphite in colour] The yields per cord, based on both the laboratory and mill tests, are fully as good as those obtained from' spruce. Immature tawa was readily pulped 'under laboratory conditions, the nature of lite product being determined by the cooking methods used. Deduction of the total time to about nine hours gave a pulp suitable for newsprint purposes, aud obtainable in high yield. In the mill tests the large proportion of mature wood used ■was actually refined without difficulty, and in all probability, altered cooking conditions will reduce, or even eliminate, this small difficulty. The yields per cord in both series of tests were from ten to 20 per cent higher than for spruce. . ' .Corsica®

pine, Austrian piue, insignis pine and European larch, were .reduced' without difficulty by the sulphate method, and a pulp produced comparing favourably with the so-called "Number One” kraft pulp on the North American market. Rimu produced the best pulp, with the woods following in the order given above. .Rimu slabwood yielded a slightly inferior pulp to that secured from roundwood. ■lnsignis Pine Newsprint. The first laboratory efforts to produce a newsprint, followed standard North American and European practice and combined varying proportions of groundwood and sulphite pulps, papers of corresponding "furnishes” being produced from both spruce and insignis pine. The in-, signis pine newsprint exceeded in strength the spruce newsprint, but was of somewhat poorer colour, and when made from pulpwood containing core rot, knots and blue stain, was dirtier. Gleaner papers resulted from pulpwood from which these defects were eliminated, and, when run over the printing presses of tbe Wisconsin State Journal, behaved exceedingly well, and were declared by the publishers to be equal to the average commercial newsprint in regard to colour, bursting strength and printing qualities. Summarised, it would appear that a good commercial grade of newsprint, consisting of 25 per cent, sulphite and 75 per cent, groundwood, may be produced from insignis pine. Insignis Pine—Tawa Newsprint. In their initial stages the efforts to produce a satisfactory insignis pine newssheet were discouraging, and attention was directed to the production of a new type fo newsprint. The experiments confirmed the theory that a small amount of long fibred insignis pine sulphite pulp (about 15 per cent.) should still be used to give tearing strength to the sheet, that hardwood sulphite from tawa ■ (about 50 per cent.) should be substituted for a large part of the softwood groundwood to ’give bursting and tensile strength, and that a fair proportion of hardwood groundwood from tawa (about 35 per cent.) should provide the necessary opacity. So successful were the initial experiments that attention was concentrated upon the problem of producing a combined softwood-hard-wood newsprint and eventually some very fine sheets equal to.and better than the commercial softwood newsprint, were pro-' duced and run over. the presses of the “Wisconsin Journal.” ' , . . . . Considering the fact that .this furnish a combined softwood and hardwood sulphites and hardwood groundwood-was an altogether new one, it was thought advisable to extend this portion of the study to a commercial scale, and to have the paper produced on full-sized fast-running machines. A shipment of insignis.pine and tawa was pulped by the Great Western Paper Company at their Ladyship plant, and made into paper at the. Wisconsin Rapids plant of the Consolidated Water Power and Paper Compauy. The commercial trial fully justified itself, not only in producing a newsprint whose colour, strength, cleanliness, and finish was equivalent to that of standard news, but in solving many practical pulping and paper-making problems which had not been apparent in the laboratory i,qsls, and which will be reflected in the design and operation of any pulp and paper mill which may be found feasible in this country. One remarkable feature about the combined insignis pine-lawn pulps is the high finish which they may be given, sufficient, indeed, to fnake the paper useable for machine finish book or rotogravure paper. \ Future Development. In addition to making a study of the technique of pulping and paper-making processes, Mr. Entrican has been engaged upon an investigation of the. economical and financial aspects of the industry, both in North America and Europe, and the Government has decided to make a detailed field examinatiop of the commercial possibilities in promising localities. The study will cover wood supplies, transportation, chemical supplies, water, power, and fuel, manufacturing and other facilities, labour conditions, etc. The industry is such a highly technical one, and involves such a large capital investment, that the utmost eare must be exercised in its establishment in New Zealand, otherwise a precipitate failure will unduly prejudice tbe later developments and expansion of the industry. To achieve economical results, mills should be of considerable size. For instance, the minimum size for a complete newsprint mill (i.e. both pulp and paper) is probably 100 short tons (20001 b. per day, if not more, and this would involve a capital investment of about £1.000,000. New Zealand’s consumption of paper, however, is small, and further than that, the world market for both pulp and paper is in a parlous condition, and unlikely to recover for at least five years. s.