Effect of Carrier Chemicals on the Optical Properties of Paper Surface-Sized with Fluorescent Whitening Agents

Abstract

Fluorescent whitening agents (FWAs) are important chemicals for improving the CIE whiteness and ISO brightness of papers. However, papermakers must reduce the amount of FWAs added to their products because FWAs present many disadvantages associated with the papermaking process, as well as paper quality; the public also has concerns about these chemicals in papers. Because the first step to reducing FWAs in the papermaking process is to improve their whitening effect, a new strategy for the effective use of FWA carrier chemicals must be developed. In this study, the whitening effects of tetra-sulpho FWA (T-FWA) and hexa-sulpho FWA (H-FWA) are compared in surface sizing, as well as with carrier chemicals. H-FWA showed a greater whitening effect than T-FWA in surface sizing, and carrier chemicals improved the optical properties of the paper when surface-sized with FWAs. It is concluded that carboxymethylcelluloses (CMCs) were a more effective carrier chemical for T-FWA; polyvinyl alcohol (PVOH) is effective with H-FWA in the surfacesizing process to increase paper sheet whiteness.

Size press practices and formulations affecting paper properties and process efficiency: A Review

“…Because starch plays such a large role in most size press operations (Cushing 1979), this section will first consider its main chemical properties, its most important sources, from the standpoint of papermaking, how it is separated from other components of the plant source, and how it is prepared for use at the size press. Other options include polyvinyl alcohol (PVOH) (Kane 1978;Lertsutthiwong et al 2004;Kim et al 2017;Bhardwaj and Bhardwaj 2018;Abhari et al 2018a,b;Liu et al 2021) and carboxymethyl cellulose (CMC) (Paltakari and Lehtinen 2009). Optional additives include hydrophobic agents, colorants, and fluorescent whiteners.…”

“…However, due to some unique characteristics, there are reasons to consider increased usage in the future of both chitosan and guar gum. Carboxymethylcellulose (Oakleaf and Janes 1977;Poranen and Kataja 2000;Gencoglu et al 2010;Kim et al 2017), methylcellulose, and alginates also have been applied at the size press in the past (Cushing 1979).…”

Effect of enzyme type on the control of fluorescent whitening agents during recycling

“…The starch solution was prepared and surface sizing was performed as described previously (Kim et al 2017;Lee et al 2015). The starch solution (concentration: 10%) was prepared by cooking oxidized starch at 90 °C to 95 °C for 30 min.…”

“…However, the amount of recycled white paper is limited because it contains FWAs, which can be a problem according to the laws (Jiang et al 2015). In addition, many consumers have considered FWAs to be toxic, despite the lack of clear evidence for this assessment (Kim et al 2017). Considering that the pulp self-sufficiency rate of the Korean paper industry is lower than in other countries (Jeong 2016), it is necessary to develop a technology capable of effectively controlling FWAs in the recycling process in order to maximize the amount of high-whiteness paper.…”

“…In this study, FWAs were classified into two groups, namely, internal FWA (disulfo FWA; D-FWA) and surface-sizing FWA (tetrasulfo FWA; T-FWA) (Perng et al 2015;Kim et al 2017). Two types of model papers were prepared-internally treated paper with D-FWA and surface-sized paper with T-FWA.…”