Y. Perng, E. I. Wang
2010
Citations
0
Influential Citations
0
Citations
Journal
Journal name not available for this finding
Abstract
Purposes of this study were to use fluorescent OBAs to study the effect of BCTMP content in papermaking stock on the optical properties of the resulting paper, and finding means of improving problems associated with BCTMP use, such as paper yellowing and the tendency for such paper to have lower brightness and apparent whiteness. The OBAs used were commercial di- (2S) and tetra-sulpho (4S) types which were added to pulps having different BCTMP contents. The optical properties, including brightness, apparent whiteness, CIE L*a*b* values, and light-fastness of the resulting handsheet were then tested. The results indicated that with regard to brightness and apparent whiteness, the 2S-OBA group exhibited greater efficacies than the 4S OBA group, At an OBA dosage 1.0%, however, then 15% of BCTMP in furnish yielded the best effect. The 2S-OBA tended to shift the paper color more toward the green-blue axis than did the 4S-OBA. Green point occurred when 2S-OBA dosage reached 1.0 to 1.5%; and for 4-S OBA it was 1.5%. Yellowing of paper tended to increase with increasing BCTMP content. In BCTMP containing paper, adding OBAs decreased the yellowing trend which was proportional to the OBA dosage. Yellowing was more moderate with the 2S-OBA than the 4S-OBA with regard to apparent whiteness, however, for brightness measurements, both OBA groups had similar yellowing trends. Summarizing the above results, the 2S-OBA was more suited to BCTMP-containing furnishes.