抄録
For obtaining high brightness pulp, O2, O3 and H2O2 bleaching and subsequent ClO2 bleaching have been carried out with two sorts of unbleaching pulp obtaind by alkali-oxygen pulp-ing process with pulping condition (I) and (II) from rice straw. And the effects of those bleaching was evaluated on the basis of brightness and paper strength of pulp obtained by oxidative bleaching and by subsequent ClO2 bleaching.
(1) The both unbleached pulps were possible to obtain more higher brightness with O3 bleaching, but paper strength, especially tear factor were decreased remakably.
(2) The unbleached pulp obtained with pulping condition (I) were increased generally 5 points of brightness with O2 and H2O2 bleaching, but the unbleached pulp obtained with pulping condition (II) were not improved thier brightness with those bleaching.
(3) The bleached pulp of brightness over 80% were obtained from O3 bleached pulp and commercial Cl2 treated pulp with one stage bleaching. But paper strength of the former had showed remakable low value and it was necessitated to investigate appropriate protector for O3 bleaching.
(4) For obtaining the bleached pulp over 80% brightness from pulp obtained with O2 bleaching, two stage ClO2 bleaching were required, but paper strength of obtained pulp were maintained same strength with original pulp. And the pulps obtained with H2O2 bleaching and subsequent two stage ClO2 bleaching were not attained to brightness over 80%.
