Application of TiO_2 to Improve the Brightness Stability of HYP Containing Coated Paper

摘要

Eco-friendly high-yield pulps (HYP) are becoming increasingly used to product high value-added fine paper that is traditionally produced exclusively with chemical pulps. However, due to the presence of a large quantity of photosensitive lignin in the HYP pulp to more effectively utilize woods resources, there is a concern on the long term brightness stability of HYP containing paper. In this research, various TiO_2 was added to coating colors to improve the light fastness properties of HYP containing coated paper. The effect on the stability of optical properties of coated paper including brightness, opacity, color difference and the degree of brightness reversion before and after accelerated aging were studied. It was shown that the brightness stability of the HYP containing coated paper increased with increased addition of TiO_2. Rutile TiO_2 was especially more effective than other types of TiO_2 on yellowing inhibition of coated paper. At a dosage of 3 parts of rutile TiO_2, the brightness stability of coated paper containing 20% of HYP was found to be even better than paper made of 100% chemical pulp coated with conventional coating color.