Neutral sizing technology

The use of AKD emulsions as sizing agents has transformed the papermaking process from acidic papermaking to technologically advanced alkaline papermaking. 1. Characteristics of Alkaline Papermaking: 1 The sizing agent was changed from rosin soap to AKD emulsion with good sizing performance. 2 filler from talcum powder to whiteness, light scattering performance, low cost calcium carbonate. 3 The fixing agent was changed from bauxite (aluminum sulphate) to a non-fixing agent and a dual retention system consisting of a retention agent cationic starch and polyacrylamide (PAM), which increased the first-term retention rate to more than 70%. 4 The papermaking wet-end system was made of paper under acidic conditions (pH 4.0 to 6.5) and changed to papermaking under alkaline conditions (pH 7.5 to 8.5). 2. Advantages of Using AKD Emulsion Using AKD Emulsion to Change to Alkaline Paper 1 Significantly improved paper properties: Paper strength (breakage, crack length, fold-tolerance) increased by about 10%, whiteness, opacity Improve 3-5%, water resistance more than doubled, and both oil resistance, anti-alkaline, anti-aging and printing performance significantly improved. 2 Saving slurry cost: Due to the use of fillers instead of some fibers, calcium carbonate broke paper can be copied back, and the one-way retention rate of the filler can be increased by more than 10%, thus saving about 3-5% of the slurry. 3 Because aluminum sulfate is not used, the load of soluble solids in white water is greatly reduced, and white water can be closed to recycle, reduce environmental pollution, and save water. 4 As the papermaking under alkaline conditions can reduce equipment corrosion, prolong the service life of gauze and felt. 5 Reduce energy consumption: It can reduce the degree of beating and reduce power consumption. As the drainage performance is improved, the drying effect can be improved and the steam consumption can be reduced. 3 The wet system of the paper machine is clean, with little foam and no dirt, improving the running performance of the paper machine and increasing the production capacity. Therefore, using AKD for neutral sizing has the unparalleled superiority of the above-mentioned acidic limbs. Although the unit cost of chemical raw materials is increased by RMB 50/ton after the AKD neutral sizing, the total cost of the above-mentioned items is about RMB 100/ton lower than that of the acid sizing. Due to the use of AKD emulsions for neutral sizing, significant economic and social benefits can be achieved. Therefore, more and more knowledgeable people from paper mills have realized the necessity and superiority of using AKD emulsions.