The Treatment On Stickies In OCC (Old Corrugated Container) Pulp With Cationic Modified Talc

As the pressure of environment and shortage of energy, the amount of secondary fiberutilization in the papermaking industry has increased greatly and recycling fiber has become animportant kind of raw material for papermaking. With the widely recycling of OCC, stickiesbring a great many of problems to papermaking；As the recovery processes cannot completelyremove the stickies from secondary fibers, the residual stickies will accumulate in white watersystem and cause problems to the paper machine and paper sheet.This paper employed CA (cationic additive) to modify common talc, and used themodified talc to deal with stickies in OCC pulp. Stickies were separated by sedimentationmethod; the extracting of the separated fibers could verify the effects of processing andsettlement; the physical performances of hand-sheets made from treated pulp were analyzed;the mechanism of modified talc dealing with stickies was studied by means of scanning electronmicroscope, Zeta potentials and model experiments, as well; the influences of differentmodification conditions on treatment effect were researched; five types of modified talc werecompared in this research. The results are as follows.1. Cationic auxiliary CA was used to modify common talc; it was found that thesettlement amount increased at first and then decreased with the increase of CA,increased with the increase of temperature; and increased firstly and then keptunchanged as the extension of time under certain conditions.2. Five kinds of modified reagent: HCA-5000, HCA-monomer, C-Starch, M2and CAwere compared. They were used to modify common talc under the same condition andfive types of modified talc were used to treat OCC pulp under the optimal condition;the growing up order of settlement amounts: HCA-5000, HCA-monomer, C-Starch,M2, CA The rank could be explained that the molecular chains of CA and M2wereshort and the electric charge was relatively weak, so the treated stickies were easyseparated from the pulp; the molecular chain of C-Starch/HCA-5000was longer, andthe electric charge was strong, so the treated stickies were not easily separated fromthe pulp.3. Flaky and layered structures of the CA modified surface were clearly observed in itsScanning electron microscope pictures. Specific surface area also increased.4. The treatment effect of modified talc was better than that of common talc inprocessing pulp. CA modified talc and common talc treated OCC pulp containingstickies respectively, and the treatment effect of cationic modified talc was superior tothat of common talc. Common talc didn’t reflect any effect in processing stickies. 5. When CA modified talc was used to treat OCC pulp, the influence of treatmentconditions on the settlement amount was great: when treating temperature rose from50℃to80℃, the settlement amount increased significantly, and then remainedrelatively unchanged while continuing to increase temperature; when processing timevaried from3min to10min, the settlement amount also increased, and then remainedthe same while continuing to prolong time; when processing concentration improvedfrom3%to21%, the settlement amount increased greatly, and continued to improveconcentration, the change was very small.6. The OCC pulp was processed at the following conditions: talc dosage (2%),temperature (80℃) and pulp concentration (21%). THF was used to extract the upperOCC pulp after settlement. It was found that with the increase of common talc from0to2%, residual stickies remained unchanged; however, with the increase of modifiedtalc from0to2%, residual stickies fell to about43%7. Tension, burst index, tensile index and tear index of OCC hand-sheet decreasedslightly after the treatment by CA modified talc.8. Modified talc was used to deal with hot melt adhesive, unbleached kraft pulp(containing hot melt adhesive) and unbleached kraft pulp, the result showed that hotmelt adhesive and fiber could both adsorb modified talc, but the adsorption capacity ofhot melt was stronger than that of fiber; the adsorption amount of unbleached kraftpulp containing hot melt adhesive was less than of that of hot melt adhesive becauseof the interference factors of fiber.9. After the treatments of CA modified talc, common talc, and CA on OCC pulp, itshowed that CA modified talc had a greater influence on the Zeta potential thancommon talc in the same dosage, but CA had no obvious effect on Zeta potentialbelow a certain dosage.10. The model experiment showed that: common talc and NA modified talc could bothmake hot melt adhesive dispersed, and the adsorption amounts were relatively small;CA modified talc could make hot melt adhesive produce hot melt adhesive-talc balls,and the adsorption amount was high.