PRODUCT CARBON FOOTPRINT OF LIOFOL SYSTEMS BY HENKEL AG

Transcription

1 PRODUCT CARBON FOOTPRINT OF LIOFOL SYSTEMS BY HENKEL AG Documentation Case Study input to PCF Project Germany

2 Content 1 Executive Summary Preface The PCF Pilot Project Goals and Scope Objectives of the Case Study Liofol Adhesives Methodology for estimating the carbon footprint of products Functional units System Boundaries Data Sources and Data Quality Allocation Inventory and Calculation Product and process description Solvent-based laminate Solvent-free laminate Water-based laminate Extraction of Raw Materials Production Feedstock materials Processing of feedstock materials Transport of feedstock materials Distribution Shopping Tour Product Use: The lamination process Recycling/Disposal Presentation of Results Overview Adipic acid Processing / Production Packaging...19 I

3 6.5 Transport Assessment of the Results Sensitivity Analysis + Uncertainty and Error Analysis Uncertainty recognition through safety factors Uncertainty in modelling adipic acid Uncertainty due to additional ethylene solvent evaporation Uncertainty in the acrylic copolymer data Conclusion regarding uncertainties Analysis of other Environmental Impact Categories Conclusion References List of tables Table 1: Effects of applied uncertainty factors on the final results... 9 Table 2: Energy and process water consumption for the processing of all Liofol types Table 3 Assumptions for the lamination process Table 4: Greenhouse gas emissions of Liofol adhesives in kg per 100 m 2 of packaging material. 16 Table 5: Overview environmental impact of 1 kg Adipic Acid Table 6: Environmental impact through Henkel combined-cycle plant List of Figures Figure 1: Considered process steps of this study... 5 Figure 2: Example of a laminating machine: Variocater LF by Windmöller & Hölscher ( 11 Figure 3: Material flows of the three adhesive systems for the FE of 100 m 2 of double layer laminated packaging Figure 4: Life-cycle greenhouse gas emissions for applying Liofol adhesives to 100 square meters of two-layer packaging material Figure 5: Share of life cycle stage emissions for the solvent-based product systems Figure 6: Share of life cycle stage emissions for the solvent-free product systems Figure 7: Share of life cycle stage emissions for the water-based product systems Figure 8: Global warming potential of different packaging alternatives used for adhesives20 Figure 9: Comparison of transport emissions for various destinations Figure 10: Uncertainty due to the use of secondary data II

4 Figure 11: Uncertainty due to the use of secondary data, including data for adipic acid. 23 Figure 12: Uncertainty due to potential need for larger solvent-based application amounts. 24 Figure 13: Uncertainty analysis due to the use of different Ecoinvent data sets to represent acrylic copolymer. The error indicates the potential that the GHG emissions from the acrylic copolymer are largely overestimated as well Figure 14: Life-cycle greenhouse gas emissions for 1 kg of Liofol adhesives Figure 15: Life-cycle greenhouse gas emissions for 1 kg of Liofol adhesives using secondary data for adipic acid and including safety factors Figure 16: Life cycle contribution to environmental impact categories for the three Liofol systems. 28 Figure 17: Life cycle stages contribution for solvent-based Liofol Figure 18: Fine particle emissions of the three systems plotted for both functional unit and comparative unit III

5 IV PCF of Liofol Systems by Henkel AG

6 1 Executive Summary The study analyses the carbon footprints of three adhesive systems by Henkel AG, which are used for laminating composite food packaging materials. The analysis is a cradle to application study and relies to a large extent secondary data. The comparative carbon footprint analysis of the three lamination adhesives shows that the solvent-free adhesive is a comparatively low-impact system with regard to the greenhouse gas emissions as well as with regard to other environmental impact areas. Of the three systems a solvent-based, a solvent-free and a water-based system offered by Henkel AG the solvent-free system fares best when taking the energy needed during the application into account. This ranking remains, even if data insecurities and high emissions data for adipic acid production are used. The major reason why the solvent-free adhesive fares best within the group of adhesives is that it does not require much additional energy in the application phase. The bond of the solvent-free adhesive occurs through chemical reaction of the two components. The energy that enters the lamination process through the spackle is sufficient to cure the bond. Both other systems require additional heat in order to foster the chemical reaction and to evaporate the solvent or water. Since solvent-free adhesives have comparable bonding characteristics than solvent-based systems, solvent-free systems would be a preferable choice on environmental grounds. Its low energy demand during the application phase also may generate cost savings for the users. The water-based system could not convince with low environmental impacts, although results depend on data sources, assumptions and contain large data uncertainties. The water-based system looses much of its low impact per kilogram of product due to its high application amount and the need to evaporate water after the application. Since the waterbased systems can not offer similar bonding characteristics than the solvent-based or solvent-free systems, its environmental performance must be assessed critically. The study confirms that product carbon footprints are a valuable tool comparing different manufacturing processes and product systems, identifying hot-spots and emission drivers, improving manufacturing processes and pointing to further improvement areas. The study is also a helpful tool to focus on particular data improvements. It also shows that the level of uncertainty may be large with particular products, such as complex chemical products, and thus conclusions should be made carefully. For example, a clear distinction in GHG emission performance between the solvent-based and water-based system can not be made based on the environmental findings. Furthermore, product carbon footprints are not sufficient to comprehensively assess and label the environmental impact of products, for which a full life cycle analysis would be required. 2 Preface The Institute for Applied Ecology (Öko-Institut e.v.) has conducted the product carbon footprint (PCF) analysis as PCF pilot project in the context of the project PROSA pro Klima 1

7 the carbon-related component of the Product Sustainability Assessment project. PROSA pro Klima is funded by the German Research Ministry (BMBF) within the context of its Social- Ecological Research Programme (Programm Sozial-Ökologische Forschung, SÖF). The executing agency was the National Research Centre for Environment and Health (Forschungszentrum für Umwelt und Gesundheit, GSF). The PCF study was made possible through financial contributions and data support by Henkel AG. 3 The PCF Pilot Project Goals and Scope The PCF project aims to develop a sound methodology for calculating product-related greenhouse gas emissions that may be used for quality controls or further in business-tobusiness or business-to-end-user communications. Until today, no standard format for calculating product-related greenhouse gas emissions or product carbon footprints (PCFs) has been agreed upon. However, there are several templates for a methodological approach. First is the international norm on life cycle assessment, ISO Series. ISO 14040/14044 started to materialize in 1997 and presents an international standard that links life cycle assessments with due diligent processes, data quality control and environmental management. Secondly there are standards and approaches for calculating corporate greenhouse gas balances (ISO 14064, GHG Protocol). They too may provide important information and insights on how to calculate aspects of the product value chain. Thirdly the British Standards office has published its final version of the PAS 2050, Specification for the assessment of the life cycle greenhouse gas emissions of goods and services (BSI 2008). PAS stands for Public Available Specification and is a non-binding standard, hierarchically below ISO norms. However, both PAS and voluntary initiatives have the power to become de-facto standards and may influence the international norm-setting process by virtue of establishing a methodology. Thus the major goal of this study is to gain experience with an applied PCF and to inform the process for developing a sound PCF methodology. While life cycle assessments have been used traditionally in a scientific way and for internal purposes, it is apparent by the discussions that a PCF has the potentials for communicating performance to business and private customers. Therefore the question of communication and of goals and aspirations is intrinsically linked with developing a sound methodology. The following PCF was carried out in accordance with the ISO 14040/14044 norm. The ISO 14040/14044 approach presents the most comprehensive approach to date. However, the investigation of other environmental effects than climate effects was limited to acidification, eutrophication, fine particle health impact and ozone formation. This pilot study tries to find answers to the questions, What does a PCF say? How sound are the calculations? What conclusions can be drawn? 2

8 Where are the limits? Where are the risks? How can it be used? In which way does it inform the consumer and user? Is PCF a suitable indicator for responsible performance? Henkel AG participates in the PCF pilot project with a group of business-to-business products as one of two product groups. The products are adhesives used to fabricate composite packaging materials for food and household goods. The particularities of the products pose particular methodological challenges for deriving and using a PCF. As with many other chemical products, some potentially harmful substances are used during the manufacturing process. Their impacts, in particular on the manufacturing side, might affect the ambient air, water and soil. Thus, one question to be asked is whether a PCF can be sufficient in mapping the advantages and disadvantages of products, or whether the inclusion of other environmental criteria would be necessary. A second challenge might be the definition of the system boundaries and functional unit (FU). Since the product is an input stream into a package material, knowledge about the PCF might be interesting for industrial customers. End consumers will rarely notice the differences of the interim products and their performance. An important question for end consumers might be how alternative systems of food packaging compare to systems that use composite materials. A significant aspect of alternative packaging systems is their behaviour when they become post-consumer waste. However, those questions can not be answered as they lay outside the scope of this PCF study. 3.1 Objectives of the Case Study Liofol Adhesives The goal of the study of Liofol adhesives, branded by Henkel AG, is to estimate the greenhouse gas footprint of three different adhesive systems. Three major systems are on the market today solvent-based, solvent-free and water-based systems. The solvent-based adhesives have traditionally very good adhesion quality and strength. However, solvents cause environmental and health concerns. A shift towards solvent-free and water-based systems for environmental and health reasons can be observed. 1 It is thus important and a goal of this study to comparatively quantify the environmental impacts with a focus on greenhouse gas emissions. On a screening level, the study considers other environmental impact areas than greenhouse gas emissions in order to detect potential critical environmental effects. 1 The study compares the climate change effect of three different systems of packaging adhesives manufactured by Henkel AG. A comparison with other products is not intended, nor is it part of this study. Nor is it in the scope of the study to make any suggestion on the quality of the products, or whether the products are fulfilling regulatory requirements. 3

9 The result of the study may be used threefold, to inform the development of a sound methodology for conducting PCFs, to provide Henkel AG with a better understanding of the environmental aspects along the product value chain and to allow Henkel AG to communicate the climate change related effects of the three product systems. This study will be made public through the web-side of the PROSA pro Klima project. 4 Methodology for estimating the carbon footprint of products 4.1 Functional units According to ISO 14040/14044 a functional unit (FU) shall be selected that provides a reference to which the input and output data are normalized. The aim is to offer a measurable yardstick that is consistent with the goal and scope of the study. The adhesives of the product family Liofol are used to laminate layers for flexible packaging together. The final packages may be heavy duty laminates, film/film and aluminium laminates for hot fill applications, film/film metalized laminates and film/film paper laminates (HENKEL 2008). The three products are a solvent-based, a solvent-free and a water-based product. Chapter 5.1 provides a more in-depth description of the three products. One aim of the study is to compare three Henkel AG (Henkel) products of the Liofol family. Thus, the FU of the product is the bonding of a defined area (100 m 2 ) of packaging material. In order to make the systems comparable, an adhesion of a two layer packaging was chosen. Multi-layer packaging systems would require several adhesion steps and therefore the multiple the amount of adhesive and greenhouse gas emissions. Furthermore, the greenhouse gas emissions for one kilogram of Henkel AG product have been calculated for informational purposes. FU The functional unit FU is the lamination of 100 square meters of a two layer packaging system of medium weight. The amount of adhesive corresponds to this FU. 4.2 System Boundaries The core assessment is a cradle to gate assessment since the investigated products are business-to-business (b-2-b) products. However, the application of the adhesives is also studied to some extent and maybe considered the use-phase of the b-2-b product. All upstream processes are included as well as the manufacturing and compounding of semifinished and final products. Transport is considered from the raw materials to distribution of the final products to wholesale and industrial customers. The lamination of two-layered packaging represents the application of the product. Waste disposal and recycling streams are in so far considered, as they are part of the cradle to gate process. Not considered are the consumer use phase of the package and its content and the waste streams after the use of the packaged product and its packaging. A detailed description of the investigated process steps of this study is displayed in Figure 1. 4

10 Figure 1: Considered process steps of this study Recently, efforts are underway to standardize the methodological approaches of product carbon footprints (PCFs). Several national and international initiatives aim to harmonize methodological and communication aspects. Currently, all initiatives orientate themselves on the International Standard for Life Cycle Assessments (ISO series). The Öko-Institut e.v. follows this protocol and takes other efforts, e.g. the UK PAS 2050, into account. Unlike life cycle assessment studies, PCFs focus on greenhouse gas emissions. The calculation of greenhouse gas emissions in form of CO 2 equivalents is an internationally approved method. According to the Intergovernmental Panel of Climate Change (IPCC), the most relevant greenhouse gases are carbon dioxide (CO 2 - being the most important greenhouse gas), methane (CH 4 ), nitrous oxide (N 2 O), and chlorofluorocarbon compounds. The sufficiency of PCFs for assessing product performance and emission reductions over time is discussed controversially. Thus other environmental impact categories are screened and analyzed whether potential significant environmental impacts are indicated. 5

11 4.3 Data Sources and Data Quality Data quality has been a challenge with this project, because nearly all the ingredients to manufacture those products are sourced from 3 rd party suppliers. An attempt to gather primary data largely failed because of proprietary concerns of the producers. Thus, for most ingredients data were taken from LCA databases combined with results from own investigations. For this purpose the Ecoinvent database version 2.1, GEMIS 4.4 and the Umberto version 5.5 data have been used in the project. While a detailed list of ingredients were available to the Öko-Institut e.v., the problem lies in the depth of detail of the LCA databases. The recipe was provided on a detailed chemical level. This detail does not exist in the LCA databases. Furthermore, since the LCA databases contain usually European averages, they may not represent the production processes of the suppliers of Henkel AG. The decision was made to add safety factors to each ingredient depending on the level of uncertainty. The safety factors range from 1.1 to 1.5 and have been proposed by Öko-Institut and verified by Henkel AG. The use of safety factors and their range have been tested in another application, where approximate numbers were compared with numbers from primary data. One ingredient, adipic acid, was calculated with primary data from the supplier to Henkel. This is in particular important because the manufacturing of adipic acid potentially releases significant amounts of dinitrogen oxide, which has a large global warming potential (GWP). The manufacturer data on adipic acid could not be verified, but is considered more sound and coherent than the corresponding unspecified data from LCA databases. Extraction of raw materials is included through LCA datasets. Data uncertainty, questions of allocation etc. are thus those found in the LCA data. Those data also include values from transportation, electricity generation etc. Transportation from the purchase of input materials to the distribution to the users of the adhesives was modelled using locations of production facilities of suppliers and locations of distribution centres. The emission factors were used from public sources, including TREMOVE for trucks (EC 2007); Ecotransit for rail (IFEU 2008), and Buhaug et al. (2008) for marine vessels 2. Recycling and disposal of waste have been modelled using LCA databases. The application process is calculated based on the energy demand for the lamination process. Those data were provided by Henkel AG. The data was derived in test runs in Henkel AG owned facilities. The machines used here correspond to lamination machines in the packaging industry. However, each machine may differ in its energy demand. The energy demand was then used to calculate emissions by utilizing LCA dataset that reflect the energy consumption from Germany s public electricity grid (medium voltage). 2 The Institute of Applied Ecology (Öko-Institut e.v.) has furthered emission factors and activity data for ocean transport. Knowledge will be published in the background report to EcoTransIT World, forthcoming in spring

12 4.4 Allocation Allocation, where applicable, was based on a mass balance. The places where allocation was necessary were the manufacturing processes, transportation and waste treatment. All other processes were added using data bases that contain already allocated effects. The allocation in the LCA data bases might be monetary or on a mass basis. 5 Inventory and Calculation 5.1 Product and process description Solvent-based laminate The solvent-based Liofol laminate is a polyurethane-based two component adhesive. It contains the adhesive UR 3644 and the hardener UR 6055 in a mixing ratio of 13:1. Solventbased laminates have been for a long time the state of the art of strong adhesives and thereby defines many customer expectations on usability and adhesion strength. The main benefits are an easy use, fast laminate speeds, good optical properties, strong initial and final bond strength and durability. Thus solvent-based adhesives are applied where strong bonds are required, in particular where different packaging materials such as aluminium and plastics are bond together. Furthermore, it is suitable for triplex-bonds after a cure time of 2-4 hours. Solvent-based adhesives however, have the negative side effects of degassing of volatile emissions and the associated smells. Many solvent-based adhesives need to be stored for a period of time to allow sufficient degassing of volatiles before any food contact may occur. Henkel s UR 3644 is based on aromatic isocyanides that cure faster and cure out under common regular atmospheric and room conditions. Its final usability is reached after storing the packaging for 7-14 days at room temperature Solvent-free laminate The solvent-free Liofol laminate is also a two-component laminate adhesive. It contains the adhesive UR 7732 and the hardener UR 6084 in a mixing ratio of 10:4. The two components are reactive polyurethane adhesives. Its main benefit is the lack of odour, common with solvent-based adhesives. Often, solvent-free adhesives have weaker bond strengths. The lamination behaviour may require lower laminating speeds compared to solvent-based adhesives. Some solvent-free adhesives may also only be suitable for a limited number of packaging materials. However, according to Henkel AG, the third generation solvent-free laminates is a high performance laminate with comparable characteristics and bonding strength than the solvent-based adhesive. 7

13 5.1.3 Water-based laminate The third product is called Avadyne and is a water-based laminate on the basis of an acrylic copolymer. It can be used to bond paper and plastic foils, including polyester and paper. Avadyne is a one component adhesive. The properties of water-based adhesives only allow for slower laminating speeds. The bond strength is lower than that of the Liofol solvent-free and solvent-based adhesives. Its application in laminating machines may also require a more sophisticated monitoring and fine adjustment to achieve the desired results and properties. Original and activity data were collected through Henkel AG. For most processes, except for adipic acid, no primary data could be collected because Henkel AG is not the manufacturer of most raw and feedstock materials. Thus, the production of nearly all feedstock materials was calculated from secondary data sources, using LCA databases. The composition of the different products was provided by Henkel AG as well as the original data for the compounding of the feedstock materials. Furthermore, Henkel AG provided the transport activity of the delivery to the top 10 customers in Europe. All transport was assumed to be conducted by truck. Life cycle emissions were added using LCA data bases, in particular Ecoinvent v2.1 and GEMIS 4.4 databases. Emissions were modelled using the Umberto v5 software. 5.2 Extraction of Raw Materials Extraction of raw materials has been included by using LCA database data for the feedstock material. Therefore no particular procedures are defined. 5.3 Production The production process within the scope of this study includes the production of feedstock materials, the synthesis of polyester and the compounding of ingredients to the final products. Most ingredients are derived from a petro-chemical process and include glycol, acids, polymers and additives. A water-based product consists of a large portion of purified water Feedstock materials The Henkel AG is, in the case of adhesives, an intermediary company that designs and produces the final products and provides the branding of those products. Most of the feedstock materials are purchased from chemical manufacturers and than compounded by Henkel AG. The expertise and knowledge of Henkel AG is realized by developing adhesive recipes that best fulfil the desired product characteristics. Thus the recipes of the products are the intellectual property of Henkel AG in the value chain. For this reason, details on the recipes can not be disclosed with the report. The production process must be divided into the production of feedstock materials, the synthesis of polyester and the compounding of the final products. As mentioned before, it 8

14 was not possible to gather primary data for most feedstock materials, except one. Therefore, the analysis relies on secondary data from LCA datasets. Data for compounding the ingredients to form the final product were available and used. The use of LCA databases in this case has proven challenging because of the limited depth of detail in those LCA databases. The feedstock materials are a list of technical chemicals with very particular characteristics and constitutions. Additives with volume shares below 1% were ignored for this analysis, assuming an insignificant impact on the final results. The approach by the Öko-Institut e.v. was to select identical and comparable substances from databases, or to construct a chemical feedstock material from several substances, in cases where the materials themselves could not be found in the databases. Different uncertainty factors were identified and applied, depending on the degree of matching between the found dataset and the used chemical material. The uncertainty factors were established after several rounds of internal expert reviews and communication with technical experts at Henkel AG. The uncertainty factors vary between +10 % and +50 %. However, the influence on the final outcome is quite different depending on the data source and assumptions. If the primary data for adipic acid are used the uncertainty is higher, although from a lower baseline. If only database data is used, the uncertainty is lower with the solventbased and solvent-free systems, because no uncertainty factor was applied to adipic acid, which was believed to be rather too high than to low. Uncertainty when using primary data for adipic acid Uncertainty when using secondary data for adipic acid Solvent-based 3,4% 0,9% Solvent-free 11,1% 1,9% Water-based 10,3% 10,3% Table 1: Effects of applied uncertainty factors on the final results Processing of feedstock materials The processing of the different adhesive types is conducted at the Henkel production site in Düsseldorf. Processing includes the synthesis of several polyester materials and the compounding of the ingredients. The process steps and the energy and water needs are relatively similar for all Liofols, except the water-based Liofol, which does not contain polyester. The model simplifies the production step and equalizes the effort of energy consumption, demand of process steam as well as the need for demineralised and industrial process water per tonne of product. For the polyester synthesis a process of 24 hours at 220 C, heated through steam, was assumed. The Henkel own combined-cycle plant provides all electricity and steam, for processes at the Henkel AG in Düsseldorf. 9

15 Consumption of steam (combined heat & power) 243 kg/t Liofol Consumption of electric energy (combined heat & power) 165 kwh/t Liofol Consumption of nitric 25.3 Nm³/t Liofol Consumption of natural gas 8.1 Nm³/t Liofol Process water m 3 /t Liofol Demineralised water m 3 /t Liofol Table 2: Energy and process water consumption for the processing of all Liofol types Transport of feedstock materials The suppliers of the feedstock materials were known and production sites were estimated using the location of the chemical facilities of those suppliers. Sourcing occurs mostly in Germany, but also in Spain, Italy, Swiss, Belgium, the Netherlands and the UK. Many of the suppliers operate several plants in Europe and abroad. Thus a level of uncertainty of the actual transport distance exists. Regular trucks with average cargo utilization were assumed for all European transport. Transport emissions were calculated for one year production of the Liofol adhesives and then broken down to the functional unit. Emission factors for trucks were used from the European database TREMOVE (EC 2007), which represents European averages reported by the countries. Emission factors for the ferries were calculated on the bases of information provided in Buhaug et al. (2008). The calculation of the later emissions factors is based on a bottom-up methodology. After processing the ingredients, the final Liofol binders and hardeners are packaged and distributed through Henkel s distribution network. 5.4 Distribution The adhesives are industrial products for manufacturers of food packaging and other packaging materials. The adhesives are usually directly transported to the clients. Henkel AG provided a breakdown of European delivery amounts and distances for one year production. The distribution transport utilizes exclusively trucks. Emission factors and average load factors found in TREMOVE were applied. Furthermore, a list of overseas destinations was provided to allow the add-on of transport emissions for distant clients. Transport overseas is conducted via truck and containers onboard container vessels. 5.5 Shopping Tour A shopping tour is outside the system boundary. 10

16 5.6 Product Use: The lamination process Laminating machines are comparable to printing machines. For industrial applications such as large packaging manufacturers, laminating machines can have a significant size and production rate. The chosen machine for data collection is considered a representative machine. However, laminating machines may differ in their energy requirements, efficiency and material flow processing. Differences in lamination machines could not be considered. Figure 2: Example of a laminating machine: Variocater LF by Windmöller & Hölscher ( The acquisition of data for the laminating process relied on measured data from Henkel AG. The machine used was manufactured by Nordmeccanica with a scrapper width of 400 mm and laminating speeds of m/min. Lamination speeds can be much higher, at least when solvent-based adhesives are used. For all three applications an average laminating speed of 75 m/min was used. The solvent-free adhesive does not require additional drying. It is a reactive two component adhesive that chemically bonds after the mixing of the components. The necessary temperatures for laminating are introduced to the films through the scrapper and laminating mechanic. The solvent-based adhesive contains organic solvents and the water-based a large amount of water that need to leave the system. The solvent-based and the water-based adhesives require additional drying energy in a drying channel. Only electricity was used in the testing application, including for heating the drying channel. In addition, while applying the solventbased adhesive, an additional amount of solvent, usually ethyl acetate, is added. Laminating machines that apply solvent-based adhesives are encapsulated to recover the degassing solvent. The recovered solvent re-enters the system. However a loss of 5 % of the degassing solvent was assumed that would need to be replenished with fresh solvent. In some plants, recovered solvents may be used energetically. In this case, the energy demand of the solvent-based lamination process would be reduced by the amount of recovered heat but a 11

17 constant input of solvents would add emissions to the system. This option was not calculated due to the lack of data. Finally all three systems show different material flows (Figure 3). Solvent-based and solventfree adhesives are two component systems. A hardener is mixed into the adhesive shortly before application. All ingredients in the solvent-free adhesive react with each other. Thus the application weight equals the dry weight. The water-based adhesive is a single component adhesive that does not need a hardener. Both, the solvent-based and the waterbased systems have higher application then dry weights due to the loss of solvent and water. mixing-ratios + ethyl acetate Figure 3: g 3.25 g 0.6 g 1.4 g 10.0 g Solventbased Solventfree Waterbased premix premix 6.5 g 10.0 g 2.0 g lamination process g -Solvent recovery 2.0 g dry weights -water 6.0 g 4.0 g 3.5 g g loss per 100 m 2 packaging Water loss Material flows of the three adhesive systems for the FE of 100 m 2 of double layer laminated packaging. Table 3 shows the assumption for the three laminate types provided by Henkel. Solvent based Solvent free Water based Mixing ratio 13 : 1 10 : 4 N/A Application weight 3.5 g/m² Liofol + 2 g/m² 10 g/m² 6.5 g/m 2 solvent Dry weight 3.5 g/m² 2 g/m² 3.5 g/m² Drying temperature C N/A C Electricity demand 35 kw/h 3 kw/h 40 kw/h Table 3 Assumptions for the lamination process The base formula of the solvent-based system contains a significant amount of ethyl acetate. It can be assumed that the ethyl acetate from the base formula also leaves the system after the application. Thus a scenario in the uncertainty analysis assumes that an application of 4.1 g/m 2 solvent-based Liofol is required to reach the final dry weight of 3.5 g/m 2. A total 12

18 amount of 6.75 g/m² solvent would be recovered and 0.36 g (5 %) of solvents would get lost in the system. In this business-to-business product system, the use phase of the product is its application in the manufacturing of multi-layer packaging. Any use phase beyond the manufacturing of packaging materials is outside of the system boundaries of the study. The handling of the use phase in PCFs is not finally decided. While the use phase is clearly an element of an ISO 14040/14044 analysis, PCF methodologies do not uniformly recommend the inclusion of the use phase. PAS 2050 for example differentiates between energy using products, for which the use phase shall be included, and those products that influence the greenhouse gas emissions of other systems (BSI 2008). In the case of the adhesives, the selection of adhesives directly and potentially significantly influences the environmental performance, energy consumption and greenhouse gas emissions at the user level the manufacturer of multi-layer packaging. However, they are not energy using products nor do the systems significantly influence the energy usage of the finally packed goods. As stated above, the meaningful FU is a defined area of laminated packaging. The two systems that require drying (solvent-based and water-based) may be considered systems, where particular environmental aspects of the FU materialize externally at the user. The solvent-free system is instead a system where the bonding energy requirements are contained in the chemicals themselves. Thus the system boundary must extend to include the lamination process as well, which is reflected in the FU. It therefore goes beyond the pure cradle-to-gate analysis. The post-gate lamination process may be considered the use phase of the adhesive products. The calculation and the communication of those impacts to the customers allow them to draw sound and educated conclusions. The emission results of a PCF study, here a cradle to application study, should be separately viewed from the ownership of negative or positive effects from changing behaviours. The system boundary ends at the final unit of packaging. Customers may want to purchase products that save energy during the application, in particular if the savings costs are larger than additional product costs. Therefore, the information of energy consumption and GHG during application is extremely useful. It may be argued that the benefit of energy needs and savings during the use phase would be realized at the user level based on user choices in materials and methods, including potentially paying a higher price for an allegedly better and more energy efficient product. Thus, potential energy reductions and greenhouse gas savings of certain product choices would be accounted for by the user. Hence, while it could be useful to communicate the range of effects and benefits at the use level with a particular product or ways those benefits could be maximized; the numeric savings are purchased by the consumer. Since they also depend on the particular application and location, only the user can accurately calculate or measure the quantitative effects of the application of particular products. 5.7 Recycling/Disposal The only waste flows considered in this study are the disposal and/or recycling of packaging materials. Only packaging units for large amounts are in use because the Liofol products are business-to-business products. Figure 1 shows exemplary the packaging alternatives used 13

19 by Henkel. Three different types of packing alternatives PE tank, steel drum, stainless steel container are available. The carbon balance for waste cycles utilized LCA data sets. Alternative 1 is the usage of an IBC Intermediate Bulk Container. The system is composed of a reusable metal grid box on a steel skid-pallet combined with a transparent inner PE tank. After usage, the PE tank is disposed off due to the chemical contamination. An energetic recovery of the used PE tank in an average German garbage incinerator was assumed. Therefore, a GEMIS dataset was used, which describes an average German garbage incineration plant operated with plastic waste as input. The electricity produced through waste incineration diminishes the need for energy production and thus reduces greenhouse gas emissions. In this case, the equivalent electricity production from coal and gas fired power plants was considered. Figure 8 shows these credits in form of negative impacts. Alternative 2 consists of a steel drum for packaging purposes. In this case, it is assumed that the used drum is recycled in form of material recycling. The rate of recycled secondary steel substitutes the need of producing new steel from primary ores. The amount of avoided primary ore extraction is calculated as credits. Alternative 3 is the material packaging in a reusable stainless steel bulk container. After usage, the container is being cleaned and reused. The material for the stainless steel bulk container was not considered because of its multiple use cycles. Instead the energy demand for cleaning and the transport demands were considered. 6 Presentation of Results 6.1 Overview The following charts compare the global warming potential, expressed as carbon dioxide equivalent (CO 2 eq), of the applied adhesive types for the FU 100 m² of two-layer packaging. The solvent-free Liofol adhesive fares best in terms of cradle to application greenhouse gas emissions in the comparison of the three systems. It generates 0.93 kg CO 2 eq per 100 m 2 of laminate (Figure 4). The major reason for this result is the smaller amounts of the reactive adhesive that is needed to achieve the bonding of packaging layers. A second reason is ingredients in both, the solvent-based and the water-based adhesive that have a high global warming potential. In the solvent-based it their adipic acid and in the water-based adhesive it is acrylic copolymer that contribute significantly to the GHG emissions. Thirdly, both, the solvent-based and the water-based systems contain significant amounts of solvents or water that evaporate during its application. Both systems therefore require heating of the bonded packaging material, shown as energy application. It was assumed that 95 % of the solvent in the solvent-based system would be materially recovered. In some applications of the solvent-based Liofol, the solvents may be energetically used. This may influence the GHG emissions depending on the substituted energy source for the drying process. The solventfree Liofol reacts to 100% with the packaging material at room temperature. 14

20 GHG Emission Estimate for the Functional Unit (100 m 2 Laminate) Liofol Adhesives in [kg CO 2 eq/ 100 m 2 ] 4,0 3,5 kg CO 2 eq/ 100 m 2 3,0 2,5 2,0 1,5 1,0 0,5 Laminating solvent loss Tranport incl. packaging Energy Application Energy Processing Hardener Binder 0,0 Solvent based Solvent free Water based 2,88 0,93 3,59 Adhesive type + total GWP (in kg CO 2 eq) Figure 4: Life-cycle greenhouse gas emissions for applying Liofol adhesives to 100 square meters of twolayer packaging material. The major contributor to the GHG Emissions of all systems is the binder, which contribute with 47 % (solvent-based), 56 % (solvent-free) and 50 % (water-based) to the overall footprint. The solvent-free Liofol s second largest contributor is the hardener with 24 %. For the solvent-based and the water-based Liofols, the energy required for applying and drying is the second largest contributor (41 % and 38 % respectively). The application of the solventfree adhesive contributes only with 11 % to its GHG emissions. The GHG emissions for drying depend on the source of electricity and may differ for each particular application. For the study, the average German electric grid was used to determine the GHG emissions from the adhesives application. It should be noted that the presented results include primary data for adipic acid, provided by the supplier of adipic acid, original data for all Henkel processes and secondary data for all other input materials. Adipic acid is, due to its high global warming potential, a key driver of greenhouse gas emissions for the solvent-based and the solvent-free adhesive. The use of secondary data results in large differences, which is discussed in chapter 7 and However, the primary data was assessed trustworthy and therefore used for the baseline analysis. The split between binder and hardener shows large variations. The contribution of the hardener to the GHG emissions is 3.2 % (solvent-based) and 24 % (solvent-free). In absolute terms, the hardener of the solvent-free adhesive emits twice as much GHG as the hardener of the solvent-based adhesive. The reason is largely the higher mixing ratio in the solventfree system (10:4 compared to 13:1). The water-based system is a one-component system without hardener. 15

21 Base case: Primary data for adipic acid Total GHG emissions including uncertainties 2,93 FU kg/100 m2 Lamination 1,01 3,77 GHG emissions of Liofol adhesives per FE Solvent based Solvent free Water based Binder 1,347 0,516 1,779 Uncertainty Binder 0,032 0,008 0,181 Hardener 0,092 0,223 Uncertainty Hardener 0,017 0,075 Laminating solvent loss 0,091 0,000 0 Energy Processing 0,039 0,022 0,111 Energy Application 1,192 0,102 1,363 Tranport incl. packaging 0,119 0,068 0,339 Variation transport packaging 0,021 0,011 0,054 Total GHG emissions excluding uncertainties 2,88 0,93 3,59 Table 4: Greenhouse gas emissions of Liofol adhesives in kg per 100 m 2 of packaging material. The shares of the life cycle stages differ widely for each system. The binder is the major contributor for all systems, but mostly pronounced with the solvent-based and water-based adhesives. The solvent-free adhesive emissions stem from both binder and hardener. For the water-based adhesive, the binder dominates, but processing energy and transport emissions are more important than in the other two systems. The following pictures depict the differences in the contribution of the life cycle stages for each system. Share of GHG Emissions for Solvent-Based Adhesive 1,0% Feedstock LIOFOL Binder UR Feedstock LIOFOL Hardener UR ,4% 46,8% Additional Solvent Transport Feedstock Materials Energy Compounding Energy Application Transport Product Distribution 1,4% 3,0% 3,2% 3,2% Figure 5: Share of life cycle stage emissions for the solvent-based product systems. 16

22 Share of GHG Emissions for Solvent-Free Adhesive 11,0% 1,8% 5,4% 2,4% Feedstock LIOFOL Binder UR 7732 Feedstock LIOFOL Hardener UR 6084 Transport Feedstock Materials 55,6% Energy Compounding 23,9% Energy Application Transport Product Distribution Figure 6: Share of life cycle stage emissions for the solvent-free product systems. Share of GHG Emissions for Water-Based Adhesive 2,3% Feedstock Materials Water-Based Binder 38,0% 49,6% Transport Feedstock Materials Energy Compounding Energy Application Transport Product Distribution 3,1% 6,9% Figure 7: Share of life cycle stage emissions for the water-based product systems. 17

23 6.2 Adipic acid An analysis solely relying on database data resulted in significantly different emissions. The GHG emissions of the solvent-based system would rise by 34 %, those of the solvent-free system by 29 %. The reason for the large difference is the potentially significant contribution of adipic acid to the GHG emissions. Adipic acid is an organic compound with the chemical formula C 6 H 10 O 4, produced through the nitric acid oxidation of cyclohexanol in a mixture ratio 1:2. The Ecoinvent dataset was updated in 2003 and describes theoretical data from a process analysis to which more than 80 % of the total adipic acid production refers to (Ecoinvent 2007). Energy demand is estimated and refining of adipic acid is included to 99 % pureness. Abatement of N 2 O emissions is assumed to reduce the emissions by 80 %. Despite the abatement measures to reduce N 2 O emissions by 80 %, dinitrogen oxide emissions still remain the main driver for the high GHG emissions of adipic acid. N 2 O has a GWP of Thus N 2 O emissions weigh nearly 300 times compared to CO 2 emissions. Beside the chemical input of cyclohexanol and nitric acid, the demand of 31.3 MJ process heat and 1.06 kwh electricity for 1 kg adipic acid are further drivers for the significant green house gases emissions in this dataset. The following table shows all relevant environmental impact categories for 1 kg adipic acid (Ecoinvent 2007). Ecoinvent dataset GHP (kg CO 2 eq. /kg) Acidification (kg SO 2 eq./ kg) Eutrophication (kg PO 4 eq. /kg) Fine particle (kg /kg) Adipic acid, at plant Table 5: Overview environmental impact of 1 kg Adipic Acid During the project, the producer of the adipic acid for Henkel AG critiqued the Ecoinvent Data for not representing its manufacturing process. According to the supplier, their process requires only approximately 1/3 of the 31.3 MJ of heat and 1.06 kwh of electric energy. Furthermore, the supplier states that their plant historically had achieved 90 % to 95 % reductions in N 2 O emissions. With a newly installed secondary post treatment step a reduction of 99 % is achieved. The reduction from 80 % abatement to 99 % abatement would result in 18 kg less of CO 2 equivalent emissions per kg of adipic acid. The Öko-Institut e.v. could not verify the data supplied by the supplier but assesses the supplier as a credible and responsible manufacturer. Furthermore, the PAS 2050 specification gives priority to the use of primary data compared to secondary data (BSI 2008). Thus primary data with an uncertainty margin of 10 % was used as basis data and standard scenario. The difference in using the original data and database data will be shown in the sensitivity analysis. 3 According to the Fourth Assessment Report by the IPCC. Formerly the GWP of N 2 O was set as

24 6.3 Processing / Production The environmental impacts caused by the processing of the raw materials to the final binder and hardener at the Henkel production site are small, compared to the other impacts during the life cycle chain. The combined cycle heat and power plant at Henkel in Düsseldorf contributes to the small impacts of the processing step. The Henkel owned combined heat and power plant in Düsseldorf is a gas-powered plant which achieves an efficiency of 85 % due to the optimized usage of both, steam and electricity. Furthermore, oily and fatty wastes from the production site are energetically used in the power plant. Table 6 provides emissions from the Henkel power plant per Kilowatt hour electricity and kilogram steam for the environmental impact categories GWP, acidification and eutrophication. For example, compared to the GWP of 1 kwh electricity taken from the German public electricity grid (around 0.62 kg CO2 eq./kwh), the Henkel plant causes less than half of the CO 2 emissions (0.25 kg CO 2 eq). Considering the given consumption values for electricity, steam, demineralised and industrial water; environmental impacts through the processing of adhesives play an insignificant role Electricity Steam (4bar) Demineralised water GWP general 0.25 kg CO2 eq./ kwh 0.19 kg CO2 eq./ kg 1.03 kg CO2 eq./ m³ Acidification general kg SO2 eq. /kwh kg SO2 er. /kg kg SO2 eq. /m³ Eutrophication general kg PO4 eq. /kwh kg PO4 er. / kg kg PO4 eq. / m³ Table 6: Environmental impact through Henkel combined-cycle plant 6.4 Packaging Figure 8 displays the GWP caused by the recycling of the three packaging alternatives. For the PE Tank and the steel drum environmental burdens relating to the production of the packaging systems are noticeable. Both systems also receive credits for avoided emissions due to the recycling of used packages. Still, for both packing alternatives, a net GWP is calculated. The stainless steel container manufacturing emissions were omitted because of the reusability of the container. Here, the cleaning of the container was calculated. The calculated GWP from Figure 8 are based on 1 Litre content. In this case, the PE tank shows with a GWP from kg CO 2 eq. / litre, compared to kg CO 2 eq. / litre a significantly lower environmental burdens as the steel drum alternative. 19

25 GWP Packaging Alternatives per Liter Product 0,0020 0,0015 0,0010 kg CO2 eq. 0,0005 0,0000 Production Recycling Reuse Sum -0,0005-0,0010 PE tank energetic recycling Steel drum material recycling Washing stainless steel container -0,0015 Figure 8: Global warming potential of different packaging alternatives used for adhesives 6.5 Transport Comparison of CO2 Transport Emissions [kg/t] kg CO2/tonne product 0,0 50,0 100,0 150,0 200,0 250,0 300,0 350,0 400,0 450,0 Liofole Input Liofole Distribution, Europe Transport legs Distribution examples to overseas locations via Rotterdam to Japan via Rotterdam to Israel via Rotterdam to Taiwan via Rotterdam to USA Figure 9: Comparison of transport emissions for various destinations. Transport emissions are the highest for the water-based system, both in terms of absolute emissions and in terms of the share on the total emissions (Table 4 and Figure 4). The transport efforts for the raw materials are about three times the transport efforts for distributing the final products. 20

26 Figure 4 also exemplifies that it is in particular the considerations of the transport and the application that lead to the clear differences of the three systems. The water-based adhesive is marked with a high share of transport emissions, which contribute with 9.2 % to the overall emissions. Transport emissions contribute with 7.1 % to the solvent-based and 4.0 % to the solvent-free systems. The transport emissions directly correlate with the wet weight of the adhesives that is required to achieve the desired laminate. This result also shows that transport emissions can not a priori be deemed insignificant. Additionally, transport emissions are hidden in the binder and hardener feedstock materials, for which LCA data were used. Emissions from transport of raw materials are included in the Ecoinvent datasets for the raw materials and can therefore not be displayed separately. Moreover, transport emissions may double if the products are shipped to overseas locations. Figure 9 displays the CO 2 emissions for sample destinations, which would replace the emissions caused by the domestic distribution. Shipping products to the Mediterranean and trans-atlantic would add 40 % 50 % to the transport emissions. Destinations in Asia would mean to add between 75 % % to the transport emissions. 7 Assessment of the Results 7.1 Sensitivity Analysis + Uncertainty and Error Analysis The case of adipic acid exemplified that the reliance on secondary data contains a large degree of uncertainty. In the case of adipic acid, which might be an extreme case, the uncertainty reaches nearly 1/3 of the total GHG emissions. However there are several other aspects that contain uncertainties, including: The fuzziness of the chemicals and feedstock materials in LCA datasets compared to the used elements. Errors of secondary data compared to primary data for key ingredients, for example adipic acid. The theoretical and de-facto application amounts of adhesives and additional solvents, which are controlled by the users. The use of only roughly fitting elements from LCA databases, for example acrylic copolymer. The sources for the energy during the application process Uncertainty recognition through safety factors Obvious fuzziness between the used chemicals and elements and the secondary data sets was handled by applying specific safety factors to the secondary data. The fuzziness may stem from different paths of production processes or from mismatching definitions between the used elements and those described in secondary data sets. For example, the solvent-based Liofol contains a significant amount of ethyl acetate. Ethyl acetate may be derived through the estherification of ethanol or it may be derived from butane as primary source. The former process is most common, but a reference data set to 21

27 the second exists in the Ecoinvent data base. The GHG emissions for the solvent-based Liofol would be 3.3 % lower with the use of the data set ethyl acetate from butane, at plant Sutter 2007b (Ecoinvent 2007). However, ethyl acetate through etherification of ethanol was used as the base case. The underlying uncertainties pertaining to the use of secondary data was estimated. Each material that could not securely identified was given a safety factor. Safety factors ranged from +10 % to +50 %. However, in nearly all cases it only affected minor ingredients so that the overall effect of applying the safety factors is minor as well. An exception is acrylic acid, which will be discussed separately. The additional emissions due to the safety factors range from +2.4 % (solvent-based) to +10 % (solvent-free) based on the overall emissions per Functional Unit 100 m 2 of packaging material. The 10 % higher emissions of the solvent-free Liofol however, are based on the overall low baseline emissions and thus do not change the overall results. The water-based Liofol has a medium uncertainty of +6.6 % due to the use of safety factors. Uncertainties in GHG Emissions for Lifol Products due to the Use of Secondary Data per Functional Unit 100 m 2 Laminate 4,0 3,5 kg CO 2 eq/ 100 m 2 3,0 2,5 2,0 1,5 1,0 0, % % % Variation transport packaging Laminating solvent loss Uncertainty Hardener Uncertainty Binder Tranport incl. packaging Energy Application Energy Processing Hardener Binder 0,0 Solvent based Solvent free Water based 2,93 1,01 3,77 Adhesive type + total GWP (in kg CO 2 eq) Figure 10: Uncertainty due to the use of secondary data Uncertainty in modelling adipic acid As described in chapter 6.2, adipic acid significantly contributes to greenhouse gas emissions because of its potential N 2 O emissions. If the modelling of adipic acid would be based on Ecoinvent database data instead of the primary data provided by the manufacturer, the results change drastically. The GHG emissions of the Liofols when using the values for adipic acid from the Ecoinvent database are 34 % higher for the solvent-based Liofol and 29 % higher for the solvent-free Liofol 22

28 (Figure 11). While the overall result that the solvent-free product is superior with regard to greenhouse gas emissions compared to the other two products would not change, the impact on the results is significant. One, the benefit of the solvent-free to the water-based system shrinks. Second and more important, the solvent-based system would fare significantly less beneficial and would result in higher life-cycle greenhouse gas emissions than the waterbased system. As a result the water-based system would be second best when considering the greenhouse gas impacts of the three Liofol systems. However, the current approach to product carbon footprint analysis gives priority to primary data and the supplier of adipic acid is deemed a credible source of information, although the primary data could not be verified. Thus, the scenario of using secondary data for adipic acid is considered not representative for the particular Henkel products. Nonetheless shows the scenario that the results can hardly indicate the performance of other adhesive systems. 4,0 Uncertainties in GHG Emissions of Liofol Products due to the Use of Secondary data including Adipic Acid per Functional Unit 100 m 2 Laminate kg CO 2 eq/ 100 m 2 3,5 3,0 2,5 2,0 1,5 1,0 0,5 0, % % % Solvent based Solvent free Water based 3,90 1,28 3,77 Adhesive type + total GWP (in kg CO 2 eq) Variation transport packaging Laminating solvent loss Uncertainty Hardener incl. Ecoinvent data adipic acid Uncertainty Binder incl. Ecoinvent data adipic acid Tranport incl. packaging Energy Application Energy Processing H d Figure 11: Uncertainty due to the use of secondary data, including data for adipic acid Uncertainty due to additional ethylene solvent evaporation Another uncertainty stems from the calculation of the optimal application amounts to achieve the desired layer bonds. The solvent-based system contains approximately 19 % ethyl acetate in its recipe in addition to the ethyl acetate that is applied during the lamination process. If 3.5 grams dry weight solvent-based Liofol are required and if the ethyl acetate contained in the formula evaporates entirely, the amount of solvent-based Liofol to be applied would need to increase. The lamination of 100 m 2 packaging would then require 4.1 grams of solvent-based Liofol and the emissions would increase accordingly. This would 23

29 result in % with regard to greenhouse gas emissions of the solvent-based system. (Figure 12. Figure 12 includes the uncertainties due to the applied safety factors). The benefit of the solvent-based system to the water-based system shrinks in this scenario. Furthermore, the final application amount is outside the control of Henkel AG. While it can be assumed that the application amounts are attempted to be minimized by the users to reduce costs, other considerations may lead to higher than recommended application amounts. 4,0 3,5 Uncertainties due to Need for Larger Application Amounts with the solvent-based Liofol due to Ethylene Acetat Loss per Functional Unit 100 m 2 Laminate kg CO 2 eq/ 100 m 2 3,0 2,5 2,0 1,5 1,0 0, % % % Variation transport packaging Laminating solvent loss Uncertainty Hardener Uncertainty Binder Tranport incl. packaging Energy Application Energy Processing Hardener Binder 0,0 Solvent based Solvent free Water based 3,18 1,01 3,77 Adhesive type + total GWP (in kg CO 2 eq) Figure 12: Uncertainty due to potential need for larger solvent-based application amounts Uncertainty in the acrylic copolymer data The acrylic copolymer is the driver for greenhouse gas emissions in the water-based system. Here too it was not possible to obtain primary data. Ecoinvent lists two data sets that may be used to model the acrylic copolymer: an acrylic binder 54 % in water and an acrylic dispersion 34 % in water. Both data sets are imperfect in representing the feedstock material used for the water-based adhesive due to the nature of the described application. The Ecoinvent data were developed for paints and varnish applications. No details are provided with regard to the specific production circumstances and product properties. (Ecoinvent 2007) Furthermore, data on which those components are modelled originate from studies in the 1990ies and represent European production sites. As could be seen with adipic acid, new production methods, changes in the GHG footprint of the energy supply and other efficiency improvements have likely taken place between the 1990ies and today. Thus the Ecoinvent data set must be considered outdated. In addition, Ecoinvent itself states that it is difficult to 24

30 assess the representativeness of the data (Ecoinvent 2007, p. 803) due to the limited information on particularities of the original sources. The water-based Liofol contains nearly one half acrylic copolymers. Since the manufacturing of acrylic copolymers is rather energy intense, the effect on the footprint of the water-based system is significant. The standard scenario was calculated using the Ecoinvent data set for acrylic binder, 54 % in water, and adjusted to the amount of acrylic copolymer used in the water-based system. A scenario was developed using the Ecoinvent data set for acrylic dispersion, 34 % in water, and adjusted to the amount of acrylic copolymer used. This scenario results in 10.4 % higher GHG emissions of the water-based system. However, at the same time, a much smaller impact due to the acrylic copolymer may be the case if particular production processes for the specific feedstock materials were considered. The imperfect fit of the secondary data, the source year and the uncertainties in the secondary data makes the assessment of the water-based system very difficult. Uncertainties in the Acrylic Copolymer Dataset per Functional Unit 100 m 2 Laminate 4,0 3,5 kg CO 2 eq/ 100 m 2 3,0 2,5 2,0 1,5 1,0 0,5 0, % % %? Solvent based Solvent free Water based Variation transport packaging Laminating solvent loss Uncertainty Hardener Uncertainty Binder Tranport incl. packaging Energy Application Energy Processing Hardener Binder 2,93 1,01 3,91 Adhesive type + total GWP (in kg CO 2 eq) Figure 13: Uncertainty analysis due to the use of different Ecoinvent data sets to represent acrylic copolymer. The error indicates the potential that the GHG emissions from the acrylic copolymer are largely overestimated as well. Figure 13 shows the results using the two different Ecoinvent data sets. When using the data set acrylic dispersion, 34 % in water the emissions increase by 10.4 %. At the same time much lower emissions are possible. However, the lack of primary data prohibited the quantification of any possible lower emissions Conclusion regarding uncertainties The study shows that secondary data may import large errors into a carbon footprint analysis. Although individual components often contribute only marginally to final results and thus errors also might be limited in size, in certain instances large errors associated with 25

31 individual key components are possible. Each product has certain components that are drives of greenhouse gas emissions. Those drivers are adipic acid and acrylic copolymer in the studied systems. A carbon footprint analysis should aim to retrieve primary data at least for those components that are drivers for greenhouse gas emissions. The study also showed that the use of safety factors can only compensate to some extent the degree of uncertainties. The differences between primary versus secondary data would not have been covered with the use of safety factors in the case of adipic acid. In the case of acrylic copolymer, the real differences may be larger than the safety factors applied, and more importantly the real emissions may be less. Uncertainties of many other components also exist due to the use of secondary data, but do not change the results significantly. More significant might be uncertainties in the amounts applied to achieve the desired results. Increase in emissions in double digits may occur. Generally, the system with the lowest material input is the least affected by alterations of application amounts. The required energy for drying with the solvent-based and water-based system is another area of uncertainty that was not quantified. Depending on the energy source, the degree solvents are recovered and how they might be used, the energy during the application of the adhesives may vary significantly. Here too, the solvent-free system has an advantage, as it does not require any drying. The uncertainties of the carbon footprint analysis of the Liofol adhesive systems are considered significant, in particular with the solvent-based and water-based systems. However, one important finding was not affected by any of the scenario analysis: Overall the solvent-free system fares best in the comparison to the other two systems, regardless of uncertainties analyzed in this study. A preference between solvent-based and water-based systems in contrast depends on the assumptions and the available data. The water-based system may be slightly less greenhouse gas emitting if the manufacturing processes if adipic acid production is optimized. It may further fare better if primary data could be made available. However, it might be worst in terms of emitting greenhouse gas emissions if no energy efficient acrylic copolymer processes are used. Additionally, the GHG emissions for one kilogram of product was calculated, which emphasizes in particular the differences in shares of the life cycle stages independently from the amount of applied adhesive. In this comparison the water-based system fares best among all adhesives. Furthermore, the solvent-free Liofol emits less GHG emissions than the solvent-based (Figure 14). However, a comparison based on the weight of the product is not suitable because of the extremely different application amounts needed to achieve the bonding of packaging materials (see Table 3). This analysis shows the importance of defining an appropriate functional unit in this case the lamination of a unit packaging material of 100 m 2. Figure 15 further exemplifies how distinctly the use of secondary data influences those results. 26

32 GHG Emissions per Kilogram Liofol Product by Henkel using Primary Data for Adipic Acid in [kg CO 2 eq/kg] 8,0 7,0 kg CO2 eq/ kg Product 6,0 5,0 4,0 3,0 2,0 Laminating solvent loss Tranport incl. packaging Energy Processing Hardener Binder 1,0 0,0 Solvent based Solvent free Water based 4,74 4,06 2,15 Adhesive type + total GWP (in kg CO 2 eq) Figure 14: Life-cycle greenhouse gas emissions for 1 kg of Liofol adhesives. GHG Emissions per Kilogram Liofol Adhesive by Henkel using Ecoinvent Data in [kg CO 2 eq/kg] 8,0 kg CO 2 eq/ kg Product 7,0 6,0 5,0 4,0 3,0 2,0 1,0 Variation transport packaging Uncertainty Hardener incl. Ecoinvent data adipic acid Uncertainty Binder incl. Ecoinvent data adipic acid Laminating solvent loss Tranport incl. packaging Energy Processing Hardener Binder Figure 15: 0,0 Solvent based Solvent free Water based 7,71 5,86 2,38 Adhesive type + total GWP (in kg CO 2 eq) Life-cycle greenhouse gas emissions for 1 kg of Liofol adhesives using secondary data for adipic acid and including safety factors. 27

33 7.1.6 Analysis of other Environmental Impact Categories Product carbon footprints are important indicators to what extent a product may contribute to the greenhouse gas emissions. However, particular products may have impacts in other environmental areas that also should draw attention. While the location of greenhouse gas emissions is of less importance, other emissions, for example that of acidifying compounds, have more localized effects. As a consequence, it is difficult to compare the degree of emissions of different impact categories. Nonetheless, a comparison of emissions in different impact categories provides indications where else environmental problems may arise and how the different products perform. In order to assess emissions to other impact categories, the Öko-Institut e.v. evaluated the emissions that contribute to acidification, eutrophication and fine particle. All three generate localized effects. In order to compare those emissions, the normalization to the per capita emissions in Germany was used (Figure 16). Normalized to the German per capita emissions (data for 2006 from UBA), the contribution of Liofol adhesive for 100 m 2 of packaging to greenhouse gas emissions is lower than the contribution to acidification and fine particle exposure. The greenhouse gas emissions range from % (solvent-free) to % (water-based). The pattern of impacts repeats itself in the other impact categories, with the solvent-free being the least impacting product and solvent-based and water-based less beneficial, but normalized to the German per capita emissions the impacts of the adhesives are higher in other impact categories. Percent Contribution of Liofol Life Cycle Emissions to the per Capita Emissions in Germany 1,2% 1,0% % of per capita emissions 0,8% 0,6% 0,4% GHG contribution of Liofol products 100m2 packaging Acidification contribution of Liofol products 100m2 packaging 0,2% 0,0% Solvent based Solvent free Water based Fine particle contribution of Liofol products 100m2 packaging Figure 16: Life cycle contribution to environmental impact categories for the three Liofol systems. Contributions to the acidification potential are particularly pronounced. The contribution of the solvent-based product is 0.78 % of the German per capita emissions (SO 2 eq) and that of the water-based system 1.1 % or 41 times more then the respective contribution to greenhouse gas emissions. Also the solvent-free Liofol s impact to acidification is strongly elevated 28

34 compared to its contribution to greenhouse gas emissions. The emissions represent 0.32 % of the German per capita emissions or 47 times higher than its contribution to greenhouse gas emissions. The contributions of the systems to fine particle emissions are also more pronounced than their contribution to global greenhouse gas emissions. However, with roughly 10 times the contribution to greenhouse gas emissions it is not as strong as those to acidification. The analysis shows that the limitation to greenhouse gas emissions can not provide a comprehensive picture of environmental impacts of products and services. Other potentially significant environmental impacts might be missed and may have particular local relevance. A screening of other impact areas is always warranted. The origin of the emissions to other impact categories also differs widely. In the example of the solvent-based Liofol, greenhouse gas emissions originate to the same degree from the feedstock materials and from the energy input. In other impact categories the manufacturing including the feedstock materials dominates. Furthermore, transport emissions become relevant for pollutants such as nitrogen oxides and sulphur oxides. (Figure 17) Solvent-based Liofol; Contribution to environmental impact categories Cumulated Energy Demand kj/100m² verarb. Product Fine Particles kg CO2 eq. / 100m² packaging Product Feedstock LIOFOL Binder UR Feedstock LIOFOL Hardener UR 6055 Additional Solvent Eutrofication kg CO2 eq. / 100m² packaging Product Acidification kg CO2 eq. / 100m² packaging Product GWP kg CO2 eq. / 100m² packaging Product Transport Feedstock Materials Energy Compounding Energy Application Transport Product Distribution 0% 20% 40% 60% 80% 100% Figure 17: Life cycle stages contribution for solvent-based Liofol. The principle results don t change as exemplified with the impact category fine particles. (Figure 18) However, their share to normalized German per capita emissions is also higher than that of greenhouse gas emissions. (see also Figure 16) 29

35 Comparison of PM 10 Emissions for Liofole 0,020 0,018 kg PM10 / 100m² Product 0,016 0,014 0,012 0,010 0,008 0,006 0,004 Transport Energy Application Energy Processing Hardener Binder 0,002 0,000 Per 100m2 Packaging Per kg of Product Solvent based Solvent free Water based Solvent based Solvent free Water based Produkte Figure 18: Fine particle emissions of the three systems plotted for both functional unit and comparative unit. 8 Conclusion The comparative carbon footprint analysis of three lamination adhesives shows that the solvent-free adhesive is a comparatively low-impact system with regard to the greenhouse gas emissions as well as with regard to other environmental impact areas. Of the three systems a solvent-based, a solvent-free and a water-based system offered by Henkel AG the solvent-free system fares best when taking the energy needed during the application into account. This ranking remains, even if data insecurities and high emission data for adipic acid production are used. The major reason why the solvent-free adhesive fares best within the group of adhesives is that it does not require much additional energy in the application phase. The bond of the solvent-free adhesive occurs through chemical reaction of the two components. The energy that enters the lamination process through the spackle is sufficient to cure the bond. Both other systems require additional heat in order to foster the chemical reaction and to evaporate the solvent and water. Since solvent-free adhesives have comparable bonding characteristics than solvent-based systems, solvent-free systems would be a preferable choice on environmental grounds. Its low energy demand during the application phase may also generate cost savings for the users. The water-based system could not convince with low environmental impacts, although results depend on data sources, assumptions and contain large data uncertainties. The 30

36 water-based system looses much of its low impact per kilogram of product due to its high application amount and the need to evaporate water after the application. Since the waterbased systems can not offer similar bonding characteristics than the solvent-based or solvent-free systems, its environmental performance must be assessed critically. If purely one kilogram of product is studied, the water-based adhesive has less greenhouse gas emissions incorporated then the other two systems. The solvent-free system is dominated by greenhouse gas emissions incorporated in the binder as well as the hardener, whereas the solvent-based system s greenhouse gas emissions are predominately in the binder component. However, a mass based result is relatively meaningless, because the application amounts needed to create the same bond with a solvent-free adhesive are just 1/5 of the amount needed with a water-based system. The larger product mass needed with a water-based system also leads to significantly higher transport emissions, which are in all systems not insignificant. Shipping the products overseas could more than double the distribution transport emissions. Different packaging systems may also result in different greenhouse gas emissions, however, all at low emission levels and not significant for the overall results. The most beneficial packaging system is the re-usable stainless steel container. The screening of other environmental impact areas revealed that the adhesive products might affect other environmental categories more than they contribute to global climate change. Although only a limited screening was conducted, the affect to acidification and fine particle emissions for example where much more pronounced when normalized to German per capita emission levels than those for the greenhouse gas emissions. While this does not indicate a negative environmental impact of the adhesive production, it does indicate that those products play a larger role in emitting air and water pollutants than in emitting greenhouse gas emissions. The study confirms that product carbon footprints are a valuable tool comparing different manufacturing processes and product systems (preference of the solvent-free adhesive), identifying hot-spots and emission drivers (adipic acid and acrylic copolymer), improving manufacturing processes (improvements in the production of adipic acid, improvements in energy generation) and pointing to further improvement areas (transportation emissions, low carbon energy supplies). The study is also a helpful tool to focus on particular data improvements (acrylic copolymer). It also shows that the level of uncertainty may be large with particular products and thus conclusions should be made carefully. For example, a clear distinction in GHG emission performance between the solvent-based and water-based system can not be made based on the findings. Furthermore, product carbon footprints are not sufficient to comprehensively assess and label the environmental impact of products, for which a full life cycle analysis would be required. 31

37 9 References BSI 2008 Publicly Available Specification (PAS) 2050: Specification for the assessment of the life cycle greenhouse gas emissions of goods and services. Carbon Trust, Defra and the British Standard Institute Buhaug et al. 2008: Buhaug, Ø.; Corbett, J. J.; Endresen, Ø.; Eyring, V.; Faber, J.; Hanayama, S.; Lee, D. S.; Lee, D.; Lindstad, H.; Mjelde, A.; Pålsson, C.; Wanquing, W.; Winebrake, J. J.; Yoshida, K. Updated Study on Greenhouse Gas Emissions from Ships: Phase I Report; International Maritime Organization (IMO) London, UK, 1 September, 2008; EC 2007: TREMOVE. Final Report. Prepared by TML Leuven for the DG Environment. 9 July Ecoinvent 2007 Life Cycle Inventories for Chemicals. Data v2.0, Ecoinvent report No. 8 HENKEL 2008 Adhesives and Coatings for Flexible Packaging. Liofol Technical Service Center. IFEU 2008: EcoTransIT: Ecological Transport Information Tool Environmental Methodology and Data; update Commissioned by Railion Deutschland; Green Cargo AB; Schweizerische Bundesbahnen; Société Natoinale des Chemin de Fer Francais; Société Nationale des Chemins de Fer Belges; Trenitalia S.p.A.; Red Nacional de los Ferrocarriles Espanoles; English, Welsh and Scottish Railway. ISO Environmental Management Life Cycle Assessment; Principles and Framework. October