紫外線照射処理による紙の物性値の変化
1988 年 42 巻 12 号 p. 1165-1170
詳細
1988 年 42 巻 12 号 p. 1165-1170
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.
