硫酸钙晶须的改性及其在造纸中的应用

Modification of Calcium Sulfate Whisker and Its Application in Paper Making

以硫酸钙晶须(CSW)为原料,采用磷酸和氯化镁对其进行表面改性处理,采用正交试验考察了氯化镁用量、改性时间、改性温度和改性pH等因素对硫酸钙晶须溶解度和留着率的影响,并对比分析了改性晶须和传统造纸填料(碳酸钙和滑石粉)在造纸中的加填效果。通过极差分析,得出优化工艺条件:氯化镁用量(相对于CSW的绝干质量)为30%,改性温度为60℃,改性pH为9.0,改性时间为20 min。在该条件下,晶须在水中的溶解度可由0.25wt.%降低至0.02wt.%,当加填量为30%时,留着率可由24.5%提升至78.4%。随后将其与传统造纸填料(碳酸钙、滑石粉)的加填效果进行对比,纸页的物理强度性能均较好。

Calcium sulphate whiskers(CSW)is used as raw materials,which is modified with phosphoric acid and magnesium chloride.The effects of the amount of magnesium chloride,modification time,modification temperature and pH on the solubility and retention of calcium sulphate whiskers are investigated by orthogonal test.The filling effects of modifed whiskers and traditional fillers(calcium carbonate and talcum powder)are compared in paper making.By the range analysis,the optimized process conditions are obtained as follows:the dosage of magnesium chloride is 30%(relative to the absolute dry mass of CSW),the modification temperature is 60℃,the pH value of phosphate solution is 9.0 and the modification time is 20 minutes.Under these conditions,the solubility of whiskers can be reduced from 0.25wt.%to 0.02wt.%,the retention of whiskers can be improved from 24.5%to 78.4%when the filling dosage is 30%.Compare with the filling effects of traditional fillers such as calcium carbonate and talcum powder,the physical properties of hand sheets filled with modify calcium sulphate whiskers are better.