Study On Improving The Properties Of OCC Recycled Fiber And Its Substitutes Using Enzyme

Recycled fiber,which accounts for more than half of the raw materials in the papermaking industry of China,has always been the focus of attention in the industry due to the reduction of production efficiency and product quality caused by the difficulty of water drainage and hornification in the recycling process.Taking the domestic old corrugated carton(OCC)as the research object,the starch content,pulp properties and white water changes during beating were studied.And the effect of biological enzyme on the properties of waste pulp was investigated.At the same time,the effect of enzyme treatment on the properties of two commonly used waste paper substitutes was studied.The starch content in studied OCC is 10.6%(relative to the absolute dry OCC).During the beating of the OCC pulp(with a beating degree ranging from 23 to 60 °SR),the starch content and turbidity in white water both increased with the increase of the beating degree;While OCC pulp after beating is concentrated,the beating degree and the starch content of the white water both decreased,and the folding resistance,tensile index and burst index of the paper sheets also decreased.The effect of enzyme treatment on the properties of OCC pulp after beating is related to whether it is concentrated.When OCC pulp was subjected to enzyme treatment after concentration,the beating degree of the pulp didn’t change significantly under the condition of low enzyme dosage.The beating degree was reduced by a maximum of 3.8 °SR within the studied range.When OCC pulp was not concentrated after beating,the beating degree was reduced by a maximum of 6.5 °SR after enzymatic treatment,and the strength properties didn’t decrease significantly.Both amylase and cellulase were able to improve the drainage performance of OCC pulp,but amylase would adversely affect the pulp strength;while cellulase was able to reduce the beating degree,the effect on the pulp strength was not obvious.When combined amylase and cellulase to treat OCC pulp,the drainage performance of the pulp was improved without causing a decrease in pulp strength.Aiming at the problem of poor drainage performance of wheat straw high-yield pulp,enzyme treatment was used to treat it.The results showed that the drainage performance of the wheat straw high-yield pulp was effectively improved,and the water retention value decreased,but at the same time the strength of paper sheets would decline.Enzyme treatment of refined wood fiber was able to effectively reduce the energy consumption of pulping,increase the water retention value of pulp and the fiber length.The strength properties of the paper sheets first increased and then decreased with the increase of enzyme dosage.