IMPROVING STARCH REUSE WORLD PULP&PAPER 66 FennoSil 55D can maintain strength even at high ash content, unlike conventional polymer. Total retention with different polymers. Total retention was measured in the DDA tests. Figure 4 shows that the retention was clearly better with the novel amphoteric polymer than with conventional polymer. Improved retention helps in system cleanliness, runnability and in retention of additives such as size. Effect of polymers on strength. SCT strength and sheet ash content were measured from handsheets to see what effect increasing the ash content has upon strength. Figure 5b shows that ash content increased with increasing concentrations of both FennoSil 55D polymer and with conventional polymer. It can be seen in Figure 5a that SCT strength is higher with FennoSil 55D at all dosage levels and also that higher ash content decreases strength only with conventional polymer. This shows that FennoSil 55D can maintain strength even at high ash content, unlike conventional polymer. To find out the effect of FennoSil 55D polymer to board strength, SCT, Burst and CMT strength values were measured from handsheets (Handsheet test 2). Figure 6 shows that FennoSil 55D improved all these strength values. Higher starch retention with bentonite (data not shown) further improves burst strength (> 20 % increase compared to reference polymer alone). Thus, FennoSil 55D improved all key strength parameters. CASE STUDIES Amylase enzyme inhibitor chemistry has been tested at several different mills Mill trial 1. The mill was producing liner and fluting from recycled fibre and kraft pulp. During the trial, amylase enzyme Total polymer dosage, kg/t 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 97 96 95 94 93 92 91 90 89 First pass retention, % Drainage system:Alum + Polymer + Betonite Pulp:OCC 50 % + Kraft 50 % CPAM Amphoteric polymer Figure 4. Retention in DDA tests using different polymers. Figures 5a & 5b. SCT strength (5a) and sheet ash content (5b) with different polymers. Total polymer dosage, kg/t 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 11,5 11,0 10,5 10,0 9,5 9,0 8,5 9,0 SCT index, Nm/g Drainage system:Alum + Polymer + Betonite Pulp:OCC 50 % + Kraft 50 % CPAM Amphoteric polymer Total polymer dosage, kg/t 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 8,0 7,5 7,0 6,5 6,0 Sheet ash content % Drainage system:Alum + Polymer + Betonite Pulp:OCC 50 % + Kraft 50 % CPAM Amphoteric polymer