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world pulppaper 41 The principle cause of high levels of 3-MCPD found in and extracted from paper is the generation of 3-MCPD in the papermaking process Taking into account the sample size and the test methodology kitchen towel grades are permitted higher levels of 13-DCP and 3-MCPD in the final paper product. For all other food contact grades the levels permitted in the paper are one order of magnitude lower. While the recommendations originate from Germany they have been adopted by the different European countries and European Union institutions for example the 2004 Policy Statement from the Council of Europe concerning Tissue Paper Kitchen Towels and Napkins. The recommendations apply to food contact grades used in Europe regardless of whether the paper is manufactured in or imported to the region. Therefore to be active in the European market producers worldwide need to ensure that their products comply with these recommendations. The amount of 13-DCP and 3-MCPD in paper manufactured from PAE resins is dependent on a number of papermaking factors including the amount of 13-DCP 3-MCPD and PB-CPD in the PAE resin the PAE resin dosage cycle-up of 13-DCP and free 3-MCPD which is dependent on the water closure level amount of broke or recycled paper used especially if the recycled paper used a G1 resin solids before the dryer section and drying conditions. In practice 13-DCP and free 3-MCPD are poorly retained by pulp fibres. The amount of 13-DCP and free 3-MCPD in the PAE resin is an inaccurate predictor for the amount of 13-DCP and 3-MCPD that will be in the paper e.g. 1 part per million ppm of 3-MCPD in the PAE resin is not likely to result in 1 part per billion ppb of 3-MCPD measured in the paper. Paper testing is needed to ensure compliance. With current PAE resins an examination of paper test results reveals that the 3-MCPD levels are much higher than the 13-DCP levels even when there is much more 13-DCP present in the wet strength resin product. Usually papermakers struggle to meet the limits for the level of 3-MCPD while the 13- DCP level is typically well below the BfR limits. However the principle cause of high levels of 3-MCPD found in and extracted from paper is the generation of 3-MCPD in the papermaking process. G1 and G2 wet strength resins contain a significant amount of Polymer Bound CPD PB-CPD species produced from the reaction of epi and acid end groups in the prepolymer Figure 2. The PB-CPD species also known as CPD-esters are part of the polymer that is adsorbed and retained by pulp fibres and fines in the wet-end which are formed into the wet paper web in the wire and press sections of the paper machine Figure 3. In the dryer section the action of heat causes hydrolysis of the ester bond thereby generating an acid end group on the polymer and freed 3-MCPD both of which remain in the dried paper sheet Figure 4. During paper testing the total of the initial free 3-MCPD before the dryer section and the freed 3-MCPD is measured to determine compliance with the recommendations of the BfR. Figure 3. PAE Resin Polymer Retained on Fibre and Fines in the Wet Web. 13-DCP and free 3-MCPD are poorly retained but will cycle-up in the water component of the wet web. Figure 4. Hydrolysis of the CPD-ester on PAE Resin Polymer in the Dryer Section. Both the PAE Resin and the freed 3-MCPD are retained in the Dry Web and in the Paper Sheet.