環境 ＩＶ 非木材繊維の利用と問題点

Abstract

Non-wood fiber plants have been used as raw materials for the hand made paper in the Western Europe, which made from rags, and for the Japanese paper (Washi) since the old days. Thereafter, the fiber and other cells of the hemp kind, bamboo, sugar cane bagasse and cereal straw have been used as raw materials for the paper around the various Asian countries, Latin America and so on. The utilization of kenaf, sugar cane bagasse and bamboo for the pulp and paper is being extended further in accordance with the demand for the substitutes for wood and the need of the preservation of the earth environment.Non-wood fiber plants mainly signify dicotyledon with bast fiber, the grass kind and true grasses. They have slender fiber cells and offer paper strength and characteristic functions. Those characteristics including large hemi-cellulose and ash contents, however, become an obstacle to pulping and manufacturing the high quality paper as well as mixing large vessel element with the thin cell wall and little parenchymatous cell of non-wood fiber plants causes the lower quality of paper.They estimate that the quantity of non-wood fibers on the earth to be 2.5 billion tonnes, but only 20 million tonnes of them in terms of pulp are utilized for paper manufacturing. In general its raw material ratio of the pulp and paper manufacturing is low in the advanced countries and further increase of using non-wood fibers is expected. Although there are several subjects to be discussed such as overall influences on the environment of the earth including cultivation of rivalry crops and influences on the soil and materials, non-wood fiber plants including kenaf grow annually with a very large amount and good effects can be expected which are the fixation of carbon dioxide, the effective use of the solar energy, the conservation of forest, and afforestation.Varieties of paper have been manufactured from kenaf, sugar cane bagasse, bamboo, and cotton, and those papers offer good printability and other strong points which wood paper does not have. The usage of non-wood fibers will be expanded in the future if making the most of their strong points with reference to the influences on the environment of the earth.