纸浆的超声波打浆成效

以漂白硫酸盐针叶木浆(SBKP)为原料,采用机械法、超声波法、机械-超声波法分别对其进行打浆,通过对比打浆后的纤维性能指标分析打浆成效。结果表明,机械法打浆打浆度上升迅速,打浆至75°SR时,湿重由12.9 g下降至2.48 g、纤维平均长度由2.290 mm下降至0.862 mm,长纤维匀整度下降了59.6个百分点、短纤维匀整度提升了25.0个百分点,细小纤维含量增加了6.4个百分点;超声波法打浆打浆度上升缓慢,打浆至49°SR时,湿重11.08 g,纤维平均长度、纤维匀整度几乎没有变化,细小纤维含量减少0.4个百分点;机械-超声波法打浆至75°SR时,湿重6.16 g、纤维平均长度1.098 mm,长纤维匀整度下降了46.6个百分点、短纤维匀整度提升了16.5个百分点和细小纤维含量增加了3.7个百分点。同时,机械-超声波法打浆的零距抗张强度及抗张强度最高,机械法次之,超声波法最小。由此说明,机械法打浆度提高快,纤维切断和破碎严重;超声波法对纤维润胀、细纤维化有一定的效果,纤维切断和破碎较少;机械-超声波法能够保证纤维润胀、分丝和微纤化,并较好地保持了纤维长度。

Analysis of the Effect of Ultrasonic Beating on Pulp Fibers

Bleached kraft softwood pulp fibers were beaten by the ways of mechanical, ultrasonic and mechanical-ultrasonic. The beating degrees, wet weight, morphology, bonding strength and intrinsical strength of the fibers were measured to evaluate the effects of different beating processes. Results indicated that beating degree increased rapidly with mechanical beating. When beating to 75°SR, the wet weight dropped from 12.9 g to 2.48 g, the fiber average length decreased from 2.29 mm to 0.862 mm, the uniformity was decreased by 59.6 percentage points for long fibers and increased by 25 percentage points for short fibers, the content of fines increased by 6.4 percentage points. Beating degree with ultrasonic beating raised more slowly compared with mechanical besting. When beating to 49°SR, the wet weight was 11.08 g, fiber average length and uniformity were changed slightly, the content of fines were decreased by 0.4 percentage points. When beating to 75°SR by combining mechanical and ultrasonic processes, the wet weight dropped to 6.16 g, the fiber average length decreased to 1.098 mm, the uniformity decreased by 46.6 percentage points for long fibers and increased by 16.5 percentage points for short fibers, the content of fines increased by 3.7 percentage points. At the same time, the zero-span tensile strength and tensile strength were the best with mechanical-ultrasonic process, mechanical process was better than ultrasonic. All above indicated that the beating degree increased rapidly and accompanied seriously cutting with mechanical besting. Ultrasonic beating not only promoted swelling and fibrillation of the fibers, but also reduced fiber cutting and crush. Mechanical-ultrasonic beating was the best beating method, which promoted fiber swelling, fibrillation and maintained the length of fibers.