Study On Starch Coated PCC In Papermaking

Based on the high filler content in paper and the low effect to the paper strength,the thesis coated starch on PCC with the preflocculation technology and made the surface of PCC generate a starch layer to make sure the fiber and the filler particle got a good combination. The thesis researched the paper characteristic filled with starch coated PCC and their retention and drainage characteristic in wet end as a new kind of filler substitute for common PCC.The result of the research reveals that cationic starch is a kind of appropriate pretreated agent; it can reduce the drainage time effectively. The influence factor to the starch coated rate of PCC is the ratio of starch to PCC,the PCC solution concentration, the reaction time and the shearing force in reaction. Sodium hexametahposphate is a kind of appropriate cross-linking agent and it can increase the starch coated rate effectively.The infrared spectrum showed that sodium hexametahposphate can reaction with starch with P-O-C bond in solution.Take the 75g/m2 paper filled with 30% PCC for example,the ash of paper with starch coated PCC can reach 21.42% compared 18% ash in paper with common technics.adding 1% starch in wet end,the ash of paper with starch coated PCC raise 2.7% than common PCC, tensile index raise 4.17% than common PCC, burst index raise 19.7% than common PCC.the opacity of paper with starch coated PCC decrease slightly.when 0.3% AKD was used to papermaking,Cobb index decreased 29.6% compare paper with common PCC .When 0.01% CPAM was used to papermaking, the cross linked starch coated PCC showed good retention and drainage characteristic and relative good anti-shearing characteristic.under 30% filler adding condition, 0.04%CPAM and 0.2% bentonite is appropriate to retention and drainage time. The drainage time decreased 3.1s than paper with common PCC and the retention rate increase 2.16% than paper with common PCC.