Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
WeT STrengTh InnovaTIonS world pulppaper42 While initial products were based on acidic or enzymatic treatment to hydrolyze PB-CPD basic treatment is currently the most cost effective process In kitchen towel grades resins that contain small amounts of PB-CPD e.g. G2 resins can in a lot of cases still allow papermakers to produce products that comply with the BfR XXXVI recommendations due to the lower paper sample size for the BfR test method permitting higher levels of 13-DCP and 3-MCPD to be present in the paper. Where very high levels of Wet strength are used then it may be necessary to utilise a G2.5 or even G3 resin technology. However for other grades such as tea bag paper coffee filters and liquid packaging board the paper sample size used in the test method is higher thereby resulting in lower limits for 13- DCP and 3-MCPD to be present in the paper. PAE resins that contain PB-CPD species may have levels of 3-MCPD that are not compliant with the BfR XXXVI1 XXXVI2 and XXXVI3 recommendations. A PAE resin with very low or even non-detectable levels of free 3-MCPD could result in a paper with high levels of 3-MCPD if the PAE resin has a significant level of PB-CPD. Formulation and process conditions for PAE resins can minimise the formation of PB-CPD. However to achieve the very low levels of PB-CPD needed for G2.5 and G3 resins post-manufacturing processes are needed. While initial products were based on acidic or enzymatic treatment to hydrolyze PB-CPD basic treatment is currently the most cost effective process resulting in the highest efficiency PAE resins. The basic treatment destroys much of the 13-DCP. During the base treatment process most of the initial 13-DCP free 3-MCPD and PB-CPD are ultimately removed from the PAE resin due to further reaction with amine functionality on the polymer and due to further hydrolysis to glycerol. This destruction of 13-DCP free 3-MCPD and PB-CPD reduces the environmental impact and potential hazard to human health when handling these products. While hydrolysis processes can actually increase the overall free 3-MCPD in the resin the low substantivity of 3-MCPD to paper fibres relative to PB-CPD on the cationic polymer results in an overall lower level of 3-MCPD in the paper product. Additionally these hydrolysis processes allow post-treatment processes e.g. microbial dehalogenation or membrane separation to eliminate the PAE resin contribution to 3-MCPD to paper resulting in a G3 resin. G3 resins have less than 10 ppm of 13-DCP and free 3-MCPD but most importantly exhibit no potential to generate 3-MCPD due to having very low levels of PB-CPD. Use of G3 resins allows papermakers to produce products that meet all the recommendations of the BfR. Pae reSInS eFFeCT on aoX anD The envIronMenT The epi by-products 13-DCP and 3-MCPD are the focus of worker safety and food contact paper regulations. Due to their Absorbable Organo Halogen AOX contribution 13-DCP 3-MCPD PB-CPD and polymeric aminochlorohydrin ACH in PAE resins also affect environmentally driven regulations and guidelines. Legislation such as the German Waste Water Act imposes financial penalties on papermakers based on the level of AOX in their effluent stream. AOX is a blanket term that quantifies the amount of organochlorine containing compounds that can be adsorbed onto activated charcoal from water. The term and methodology used does not distinguish the chemical nature of different organochlorine containing species. It is a sum parameter for quantifying the total organic halogen load in water and is often used as a surrogate measure of Persistent Organic Pollutants POP in the environment. The methods for determining AOX have been standardised worldwide. A number of methods exist such as US EPA Method 1650C DIN EN 1485 and ISO 9562. All of these methods follow the same basic principles 1 a known quantity of aqueous sample is mixed with activated charcoal 2 the charcoal is carefully washed with nitric acid to displace and remove any ionic halides usually chloride ions from the matrix 3 the total halide TOX content is determined. In the mid 1980s a large amount of paper was produced using pulps bleached with chlorine gas. It was found that organochlorine compounds present in these pulps were the major contributor to the AOX content of a papermakers effluent stream. The AOX contribution from the bleaching of pulp has been addressed by the use of alternative bleaching techniques 1 chlorine dioxide for Elemental Chlorine Free ECF bleaching and 2 ozone hydrogen peroxide for Total Chlorine Free TCF bleaching. After bleaching of papermaking pulps the next major contributor to the AOX content of a papermakers effluent stream was found to be PAE resins. The development of Generation 2 wet strength products to address worker safety regulations by reducing the levels of 13-DCP and free 3-MCPD also resulted in the AOX content being reduced. The high levels of 13-DCP found in Generation 1 products are a significant contributor to a papermakers effluent stream. However 13-DCP and free 3-MCPD are not the only source of organochlorine species that can be determined by the AOX methodology and contribute to a papermakers effluent stream. Low 13- DCP containing resins are sometimes referred to as low AOX. However with