2 0 0 0 OA 紫外線による紙の劣化機構
- 著者
- 金 鳳庸 磯貝 明 尾鍋 史彦 臼田 誠人
- 出版者
- JAPAN TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY
- 雑誌
- 紙パ技協誌 (ISSN:0022815X)
- 巻号頁・発行日
- vol.44, no.2, pp.242-248, 1990-02-01 (Released:2009-11-19)
- 参考文献数
- 16
- 被引用文献数
- 2
In the previous papers, we have studied the influence of UV treatments on physical and optical properties of paper, and several characteristic results for UV treatments were obtained. In this paper, therefore, the mechanisms of the changes on physical properties, especially such as double folds, Young's modulus and water absorption values, by UV treatments of paper were examined in terms of molecular-order analyses of pulp and rosin chemicals.Cellulose in amorphous regions and hemicellulose are depolymerized through oxidative and/or radical reactions by UV treatments. This depolymerization leads to the formation of stable intermolecular hydrogen bond by molecular rearrangement, and thus the decrease in hydroxyl groups, which can interact with moisture or water, causes the decrease in hydrophilic properties of paper. This new hydrogen bond formation brings about the increase in Young's modulus, and even the slight decrease in moisture contents of paper probably causes the drastic decrease in double folds. On the other hand, porous structures of paper were found to be unchanged by UV treatments, and cross-linking reactions between cellulose chanis were not likely to form during the treatments.Rosin chemicals are degraded to form hydrophilic groups such as carboxylic acid from their double bonds by UV treatments. This causes the decrease in sizing degrees of rosin-sized paper, while the UV treatments bring about the increase in sizing degrees for rosin-free paper such as neutral paper owing to the formation of the stable hydrogen bond, as described above.
1 0 0 0 OA 紙の軽量化, 薄葉化の問題点
- 著者
- 臼田 誠人
- 出版者
- JAPAN TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY
- 雑誌
- 紙パ技協誌 (ISSN:0022815X)
- 巻号頁・発行日
- vol.45, no.7, pp.733-739, 1991-07-01 (Released:2009-11-19)
- 参考文献数
- 12
For saving of energy and forest resources, there is a tendency to lessen the basis weight of paper. Basis weight of newsprint decreased from 52 g/m2 to 46 g/m2 by request of newsprint company about 10 years ago. Newsprint of 43 g/m2 is produced partly. In the case of fine paper, a decrease in basis weight brings about deterioration in the mechanical and optical properties that are the most important characteristics for end uses of paper. Roughness of paper surface makes it difficult to measure exactly the thickness of paper. The fact causes many problems for definition of mechanical properties of paper. Inhomogeneous structure through z direction has a strong influence on properties of paper when the thickness is decreased. The effect of paper thickness on Young's modulus and optical properties is disccussed. The importance of drying conditions of wet web on physical properties of paper is also described.
1 0 0 0 OA 紫外線照射処理による紙の物性値の変化
- 著者
- 金 鳳庸 磯貝 明 尾鍋 史彦 臼田 誠人
- 出版者
- JAPAN TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY
- 雑誌
- 紙パ技協誌 (ISSN:0022815X)
- 巻号頁・発行日
- vol.42, no.12, pp.1165-1170, 1988-12-01 (Released:2009-11-16)
- 参考文献数
- 14
No additive paper and four kinds of paper containing rosin-alum, alum only, alkylketenedimer (AKD) -cation polymer and cation polymer only were treated by UV light in air to study changes of paper properties, from the viewpoints of natural deterioration of paper.Photodegradation of cellulose and hemicellulose chains in paper brings about the slight increase in tensile strength and Young's modulus, and the drastic decrease in folding endurance for every paper examined so far. These findings may be explained by molecular rearrangements of degraded cellulose and hemicellulose to form new stable hydrogen bonds during irradiation. Sizing and retention chemicals have little influence on such paper properties even though some of them are chemically modified by UV irradiation.Since rosin-size has UV absorption at the relatively long wavelength region, UV treatments bring about the gradual loss of sizing effects and influence wet tensile strength and water absorption properties.Optical properties are primarily influenced by additives. Rosin-sized paper showed the darkest color after UV treatment because of its UV instability. AKD seems to suppress the coloring reactions to give lower discolored paper compared with paper without additive.