MULTITUDE OF PRODUCTS FROM VERSATILE WOOD

Press, Volume CIV, Issue 30738, 30 April 1965, Page 15

MULTITUDE OF PRODUCTS FROM VERSATILE WOOD

Wood is man’s oldest, most familiar, raw material. Today wood is transformed into a multitude of products. The microscopic cellulose fibres of radiata pine—more than a million of them in an inch-square wood chip—are as strong as a comparably sized strand of steel.

These are some of the ways those fibres are released for use in the thousands of wood products now manufactured in New Zealand. A pine tree is a cylindrical package of cellulose fibres cemented together by lignin and encased in bark. The problem is to upwrap the package and separate the wood fibres for refine-

ment and manufacture into useful products. At the Kinleith pulp and paper mills this is done by modern chemical processes that convert solid wood into kraft pulp, both bleached and unbleached (for making into a variety of papers for writing, wrapping, packaging and printing), bleached and unbleached linerboard (for sturdy containers), and base papers (for reflective foils and laminated plastics). Screened. uniform-size chips from pulp logs and sawmill trimming are

dumped into digesters, chemicals are added, and the chips are “cooked,” the fibres loosening and freeing themselves from their cementing bond of lignin. The dark brown fibres may then be bleached, with chlorine, caustic soda, then hypochlorite, before moving on to the machine which forms the wet pulp into a moist sheet. This goes through a huge system of drying rollers to reduce the continuous pulp sheet to the desired moisture content. The kraft pulp is then either wound into rolls, or cut into sheets for shipping, or for making paper. MANY MARKETS To supply many markets, many basic types and qualities of pulp, papers and paperboard are produced, each tailored to the specific needs of one or more industries, and sold to them as pulp, or papers. These processes also provide chemicals for New Zealand and overseas markets, comprising sodium hypochlorite (for Neaches and cleansers), hydrochloric

acid (for glycerine, weedkillers, cleaning compounds), and vegetable turpentine. MODERN MILL The Kinleith sawmill is as modern as any in the world, with two high-speed American bandsaws, and a battery of Swedish gangsaws. Probably no manufacturing operation depends so much upon skill, experience, and judgment as does saw-milling, which involves a continuous process of sawing, edging, trimming, resawing, grading and finishing. Thousands of times a day experienced men make rapid decisions as logs and timber race through the high-speed milling processes, often at a rate as high as 800 ft a minute.