Application of Low Consistency Refining of Pulp in Producing Multi-ply Folding Boxboards

In this study, the effect of using low consistency refined (LCR) pulp in the middle-ply furnish of folding boxboards (FBBs) is examined. LCR radiata reject pulp (LCRR) with a wide range of freeness values were blended with three commercial BCTMPs to form FBB middle-ply samples. The results indicated that increasing LC refining energy of radiata reject pulp improved the mechanical strength of samples up to the optimum freeness of about 400mL. Laboratory-made three-ply FBBs with varying LCRR contents in the middle-ply were also prepared and compared to those containing 100% commercial BCTMPs in the middle-ply. It was shown that FBBs containing 45% LCRR had better mechanical properties compared to those containing only commercial BCTMPs. Additionally, the use of HC-LC refined spruce-pine-fir (SPF) pulp as the middle-ply furnish in a three-ply FBB was investigated. It was found that sulphite pretreatment of HC-LC refined pulp had no clear effect on FBB properties. In the second part of this study, the use of HC-LC refined spruce-pine-fir (SPF) pulp as the middle ply furnish in a three ply FBB was investigated. It was found that sulphite pretreatment of HC-LC refined pulp had no clear effect on FBB properties. Instead, strength properties of three ply FBB samples were predominantly a function of the freeness.M.A.S