Study On The Mixed Pulps Of Wheat Straw And Popular Pulp To Make Neutral High Brightness Paper

Bright stability of bleached popular pulp was better than that of bleached wheat straw pulp. So was the blend of bleached popular and wheat straw pulp (50:50). It was found that physical strength of the blend of bleached popular and wheat straw pulp was between that of bleached popular pulp and that of bleached wheat straw pulp. Strength of bleached wheat straw pulp could be obviously enhanced if bleached popular pulp was used in bleached wheat straw.Results showed that when pH value in wet-end was controlled between 7.5 and 8.5, cationic aids could be best adsorbed on furnish and least on filler CaCO₃. In addition high pH could help to reduce AKD sizing reactive energy. When AKD consistency was about 1%, its distribution and absorption were best and best sizing effectiveness was obtained as added in 1.0% pulp. AKD sizing effectiveness when furnish was diluted with white water was better than with water. The reason could be that there was some not remained AKD in white water, actually AKD was increased in wet-end system.Direct dyes had good appetence to cellulose, so fiber was easy to be colored up and had high colorfastness. Especially of lightfast direct dyes had 4-5 degree colorfastness so as to could keep paper color stability. VBK fluorescent agent was obtained from modified VBL. It showed slightly purple, good dyeing, good dissolution and easy reaction. From experiment as its dosage was 15%, paper did not return yellow. As its dosage was 6%, raw material brightness could be increased to 110%(ISO) and yellow back value was little. So VBK was optimal white dyes in high white paper.Silca-aluminum microparticle retention aid system was superior to conventional CS-CPAM system. Moreover CS-CPAM and Silca-aluminum microparticle retention aid system was superior to conventional CS-CPAM system. Silca-aluminum microparticle retention aid system was adapt to be used under high shearing strength and could make floc smaller and more compact so as to make drainage speed high and filtrate low turbidity.Oxidative starch cooperated with SAA could obtain favorable water-resist and film, enhance surface strength 50-150% and decreased surface water absorption 18%. Particularly it was suit to be used in paper with high filler and fine.Practice showed that high content of wheat straw pulp could be made into paper as good as whole wood pulp and paper performance was considerable or better than state standard when neutral papermaking technology, high effective microparticle retention aid system and synthesized surface sizing technology were introduced.