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WeT STrengTh InnovaTIonS world pulppaper44 high AZE level and therefore a high cationic charge are better retained than resins with a low AZE level when best application practises are employed. Additionally resins with a high AZE level typically have a low level of ACH species further minimising the PBOX contribution to AOX. With high efficiency PAE resins the conversion of ACH to AZE during manufacture is maximized and the conversion of AZE to ACH during aging is minimized resulting in lower PBOX at the time of papermaker use and therefore lower AOX in effluent. In G2 resins PB-CPD and especially polymeric ACH remain the major source of AOX in PAE resins. With G2.5 and G3 resins the PBOX content of PAE resins is further reduced by having greatly reduced the level of PB-CPD. With G3 resins polymeric ACH is the only significant contributor to AOX. When considering how much a PAE resin contributes to the AOX content of an effluent stream papermakers need to consider the actualtotal AOX content of the resin and not just the level of epi by-products present in a product. Pae reSIn eFFeCT on ToTal organIC ChlorIne ConTenT oF PaPer anD ConSuMer PreFerenCe Some manufacturers produce grades of paper considered to be Total Chlorine Free TCF. For such grades the Total Organic Halogen TOX content is less than 30 mg per kg of dry paper. These grades use TCF pulps which are produced using oxygen-based bleaching agents such as ozone andor hydrogen peroxide. Several methods can be used to determine the total organic chlorine of pulp and paper such as ISO 11480 and PTS RH1290. The principles of these methods are similar to those used for the determination of AOX content of aqueous samples except that the paper sample is mixed with the activated charcoal. The measured value is typically called Organic Halogen OX in paper. As with AOX in aqueous samples the OX in paper is a sum parameter and does not differentiate between the different species present in the paper that contribute to the final value. As with AOX in aqueous samples all the organic chlorine species present in the PAE resin will contribute to the OX content of the final paper product. The OX content in paper is primarily driven by the PBOX content and not by free epi by-products 13-DCP and 3-MCPD for G2 G2.5 and G3 resins. The following example illustrates this concept When considering the maximum limits for epi by-products in paper kitchen towel 500 ppb of 13-DCP equates to 0.28 mgkg of oX in the paper. 3000 ppb of 3-MCPD equates to 0.98 mgkg of oX in the paper. Even at the limits recommended by the BfR free epi by-products are not significant contributors to the OX content of paper. It is the Polymer Bound Organic Chlorine species PBOX of the resin that are the main contributors to the OX content of paper. Of the two PBOX species present in the resin polymeric ACH is the principle source of organic chlorine. The proprietary manufacturing processes for G2.5 and G3 wet-strength resins which were developed to eliminate PB-CPD species from the final product also reduce the level of ACH thereby reducing the total AOX and PBOX content of the resin. Therefore the same G2.5 and G3 resins that allow papermakers to minimise mill effluent AOX content will also allow manufacturers to produce TCF grades of paper. The evolution of cleaner PAE resin technology to help papermakers meet regulatory measures to address environmental and health concerns related to organochloride species has resulted in a better understanding of the PAE resin technology. Improved process control in the basic resin manufacturing process and the development of novel post-reaction techniques were needed to address these concerns. This improved knowledge of PAE resins has been used to generate products with better performance characteristics that can be shipped at higher solids across all the different generations of PAE technology. SuMMary Regulatory drivers and sustainability efforts have resulted in step-change improvements in PAE resin technology which have dramatically lowered 13- DCP and 3-MCPD levels to reduce the potential hazard to worker and consumer health and lowered PBOX species to reduce the impact on the environment AOX of mill effluent and allow for the manufacture of TCF grades of paper. Additionally in gaining an understanding of mechanisms that produce undesired organochloride species formulations and process to reduce them were developed which resulted in improvements in the wet strengthening performance of PAE resins. High solids high efficiency PAE resins contribute to a smaller environmental impact by allowing the use of less chemistry less emissions from transportation and less PAE resin and AOX in effluent. These attributes fit well with the corporate environmental sustainability programs of major papermakers. When selecting which generation of technology to use consideration of external regulatory measures is required together with the papermakers own needs to meet the guidelines of non- governmental organisations plus their own corporate sustainability programs. Improved knowledge of Pae resins has been used to generate products with better performance characteristics