Study On The Deposition Properties Of Stickies In Pulp And The Mechanism Of Enzymatic Control

The deposition of stickies will bring a range of hazards for paper machine and the quality of paper and its applications. Thus, it is very important to study on the main factors causing stickies deposition. Enzymatic stickies control is high efficiency and environmental friendly. And the optimization of the conditions for enzymatic reactions is critical to solve stickies problems.In this work, polyacrylate(PA), polyvinyl alcohol(PVA), polyvinyl acetate(PVAc), styrene-butadiene latex(SBR) were used as model of artificial polymers in stickies. While triglycerides(TG), rosin acid and palmitic acid were used as model compounds of resin. And added the compounds to bleached kraft softwood pulp that extracted with dichloromethane in different ways. It was analyzed the deposition properties of stickies’ model and found out the compound(s) having strongest deposition tendency in pulp; Then changed the temperature and pH value of the pulp suspension, and determined the impact of external conditions on stickies deposition with model compounds; Treated the compounds having greater impact on stickies deposition with StickAway, and optimized the best optimal reaction conditions. The model compounds treated with StickAway added to the pulp in alone and mix forms, and studied the effectiveness of stickies deposition control with StickAway.The results showed that:Pulp added with polyacrylate produced more macro stickies and had poorer water filtering properties than samples added with other model compounds, and triglycerides had the most impact on the filtrate. Temperature had great effect on deposition of stickies:Pulp added model compounds had a large number and area of macro-stickies in high temperature; Water filtrating time was prolonged. And the filtration of pulp performance deteriorated, filtrate cationic demand and turbidity increased. Effect of pH on the deposition of stickies models mainly resulted from the impact on nature of the model. Artificial polymers produced more macro-stickies in the alkaline pulp than in acidic ones, while the resin model produced a large amount of macro-stickies under acidic conditions. Pulp filtration performance was affected by pH too. The trend was the same as the laws of pH influencing on the stickies generated. The effect of pH on the cationic demand of pulp filtrate increased with pH value. Pulp added artificial polymer filtrate turbidity was less affected by pH, but turbidity of the sample with resin model was significantly higher under acidic conditions than that under alkaline conditions.The best conditions for esterase treating model compounds were temperature of50℃, pH value of7.5, reaction time2h, and dosages of StickAway of6LU/g(TG),8LU/g(PA). Model compounds treated by StickAway added to the pulp and produced less macro-stickies and micro-stickies, reduced water filtrating time, and improved the cleanliness of filtrate. That’s to say that the StickAway had good effect on stickies control. The size of model compounds analyzed by FBRM showed smaller after StickAway treatment. Optical microscopy revealed that the model compound particles were uniformly dispersed in the solution, and became smaller after the StickAway treatment. The IR spectra showed that the ester bond of the model molecules cleavage after the treatment of StickAway.