Amphoteric starch preflocculated talc filler for improving composite tensile index and filler bondability of paper

摘要

Filler preflocculation using carbohydrate polymer imparts good bondability to cellulosic fibres, and improves inter-fibre bonding and paper strength. The present paper throws light upon the role of amphoteric starch on composite tensile index (CTI) of paper, and filler bondability factor (FBF) calculated using ash content and first pass ash retention, and various tensile strengths of paper viz., tensile strength, Z-direction tensile strength (ZDTS) and CTI. The cooked amphoteric starch (0.1 to 0.8% on dry weight of filler) was mixed with talc filler at controlled conditions for getting the preflocculated filler. The resultant preflocculated filler was added to pulp slurry to get varying ash content of 15 to 24% in laboratory sheets of 60 gsm. The FPAR, tensile strength and ZDTS of paper sheets were measured and analysed. CTI was calculated from the results of tensile strength and ZDTS. Statistical model equations were also developed for the prediction of CTI and FBF. Paper strength and FBF reduced on increasing paper ash whereas those were protected to some extent through loading of preflocculated filler. Noticeably, CTI and FBFCTI increased through filler preflocculation up to 26% and 38%, respectively at 24% paper ash.