Study On The Properties Of Corrugated Medium By Surface Treatment Of Cellulose Fibers And Surface Sizing

Ring Crush Test(RCT) strength is one of the most important properties of corrugated medium. The capability of paper box is mostly affected by the Ring Crush Test(RCT) strength at landscape orientation of corrugated medium. In this paper, improvement of Ring Crush Test (RCT) strength of corrugated medium by surface sizing and modifying cellulose fibers was investigated. Main experiments and results were as follows:1,The effects of sizing were discussed, the results were as follows:①chemical contents was 4%-6%, sizing dosages were 3～6g/m2, sizing temperature was 60℃, drying temperature was 105℃and drying time was 4～5min.②sizing with oxide starch could improve the RCT strength; phosphate starch was amphteric, which could increase hydrophilicity of paper; sizing with PVA could reduce air permeability of paper and penetrate into paper easily; sizing with SUK-Ⅰcould improve the surface uniformity and increase the effect of sizing; sizing with hydrostable chemical could increase the RCT strength more than starch and PVA, but poor compared to SUK-Ⅰ.③Ring Crush Test (RCT) strength of corrugated medium was falling with the humidity of environment going up. The RCT strength of corrugated medium changed from 7.88N.m/g to 2.35N.m/g when it was put into moisture environment through 12 hours.2,RCT strength of corrugated medium could be improved by stiffener. The experiments results were as follows:①The stiffness of paper was improved by both adding into pulp and surface sizing with stiffener.②When added into stiffener as w=1.0%, stiffness of paper increased by almost 40% and RCT strength of corrugated medium increased by 30%. Otherwise, ash of paper increased more or less.③When sizing with stiffener(2.87g/m2) and oxide starch(9.63g/m2), the effect was equal.3,RCT strength of corrugated medium improved by modifying cellulose fibers of stock. The experiments results were as follows:①the RCT strength of corrugated medium increased at first and then go down with increase of beating degree.②chemical dosage of melamine-fomaldehyde resin was 1.0%, reaction temperature was 120℃, and reaction time was 40 min.③chemical dosage of PAE resin was 0.5%, reaction temperature was 60℃, and reaction time was 20 min.4,Mechanism of improvement in RCT was discussed.