Polyurethanes Blowing agent options for insulation foam after HCFC phase out HCFC phase out 100% 90% Consumption cap set at 2015 levels; gradual reduction begins in 2015 80% 65% 60% 40% 32.5% HCFCs have been an established intermediate alternative Mandatory review of need for service tail in 2025 20% United States of America, the use of HCFC141b in foam 2020 (non article 5) countries, such as the Russian Federation, Freeze 2015 developing (article 5) countries and in some industrialised 0% 2013 applications has been banned for almost a decade. In most 2025 to CFCs. In regions such as the European Union or the 2040 Because of their lower ODP (Ozone Depletion Potential), Figure 1: HCFC141b phase out schedule in developing countries 2030 In 1987, the Montreal Protocol was signed to protect the ozone layer by phasing out the production of a number of substances responsible for ozone depletion such as CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). CFCs have been phased out since 1996 in industrialised countries, and recently in developing countries. 2.5% Service tail HCFC141b has been the preferred blowing agent in the last decade. However, in 2007 at the 19th meeting of the n New phase-out shedule Montreal protocol, nations signed up to accelerate the n Pre Montreal 2007 phase-out shedule phase-out of HCFCs (see Figure 1). For developing countries, as of 1st January 2013, the consumption of HCFC141b will be capped and 2 years later, as of 1st January 2015, it will be gradually reduced until 2030. n Non-Article 5 countries (industrialised) n Article 5 countries (developing) 3 Blowing agent evolution The transition process from HCFC141b to alternative Examining alternatives for HCFC141b, it is important to consider blowing agents has been taking place in most industrialised the global warming potential (GWP) of replacement blowing countries in the beginning of the previous decade. As can be agents. Since the Kyoto Protocol identified HFCs as industrial seen in Figure 2, various blowing agent choices are available, gases requiring emissions control because of their high GWP, depending on technical, regulatory and economical drivers. several producers have started the development of HFOs In Europe, an estimated 85 to 90% of all insulation foams are (hydrofluoroolefins). HFOs have a very low GWP but availability currently blown with pentane technology, which has an excellent at an industrial scale is expected to take a few years. track record for both foam performance and safe handling. Figure 2 HC Flammable Zero ODP Low GWP CFC 11 HCFC141b HFC Not flammable Not flammable Not flammable High ODP Medium ODP Zero ODP High GWP High GWP High GWP Water Not flammable Zero ODP Low GWP 4 Isopentane Normal pentane Cyclopentane HFO 245fa 365mfc/227ea 134a Not flammable Zero ODP Low GWP Alternatives to HCFC141b The table shows the properties of alternative Properties of other blowing agents relative to HCFC141b blowing agents relative to HCFC141b. Pentane HFC245fa HFC365mfc/227ea Water Blowing agent price Lower Much higher None Foam thermal conductivity 5-10% higher 5-10% higher ±20% higher Foam density 5% lower density feasible Similar 5-10% higher Machine adjustments Explosion proof equipment needed Almost none Almost none GWP Low Long term solution High Low Long term solution Foam processing Limited solubility in polyols Comparable Worse surface and adhesion There is no "drop-in" replacement for HCFC141b that combines ease of use and processing alongside low operating costs. Huntsman has acquired a broad technical expertise with all blowing agent alternatives, both by the application development teams located in Ternate (Italy) and by regional teams implementing dedicated solutions at customers. PENTANE is a cheap blowing agent, which produces low WATER is obviously a cheap blowing agent but has density foams with low thermal conductivity and good limitations for both foam processing and final foam properties. properties. However, the investment to handle a flammable Foam density is substantially higher and good adhesion blowing agent is not always justifiable, especially for small foam and foam surface quality are more difficult to achieve. producers. In most cases, pentane is added to the polyol Waterblown foams also have a higher thermal conductivity. blend at the customer’s premises to avoid the transportation Waterblown foams, which are not protected by diffusion of a flammable polyol blend. In continuous operations tight facings, are subject to a gradual increase of thermal (lamination), pentane is added in line, just before the mixing conductivity over time, much more than is the case for head. In discontinuous operations, pentane is pre-blended foams produced using a physical blowing agent. to the polyol blend with suitable equipment. HFC365mfc/227ea and HFC245fa can be implemented METHYLFORMATE and DIMETHOXYMETHANE easily as replacements of HCFC141b without major changes are potential blowing agents for rigid foam, but current in foam processing. In view of the high cost of HFCs, industrial experience is limited in the European market. formulations have been finetuned towards an optimum cost / These blowing agents can be interesting options in performance ratio. HFCs are typically added by the polyol certain cases, particularly in combination with one of blend supplier and transported to the customer as a non- the aforementioned options. flammable polyol blend. The pressure build-up of HFC containing polyol blends is normally limited, but appropriate packaging of the polyol blend needs to be chosen as a function of HFC content, HFC compatibility with the polyol blend and storage conditions. 5 Blowing agent choice per application In contrast to HCFC141b, where one blowing agent was chosen The three corners of the triangle represent a situation where for all rigid foam applications, different blowing agent choices a market segment has been entirely converted to pentane, will be available after the HCFC phase out. Pentane is generally HFC or to a fully water blown solution. Positions within the triangle preferred when the foam consumption is high (e.g. in board or indicate the relative amount of producers within a segment, panel lamination). In figure 3, the blowing agent choice in that have chosen any of the three blowing agent options. industrialised countries is schematically given. Figure 3 HC European refrigerator / freezer Board / panel lamination Pre-insulated pipes Discontinuous panels, display units, etc North American refrigerator / freezer WATER HFC Spray technology Physical properties of blowing agents The physical properties of blowing It is interesting to note the differences HFC365mfc HFC365mfc/ 227ea 93/7 HFC 134a CYCLO PENTANE NORMAL PENTANE ISO PENTANE 150 102 70 72 72 40 30 -27 49 36 28 11 11 11 12.5 11.5 13.5 12.5 None None -24 None None -40 -49 -51 Solubility in polyols (1=low, 5=high) 5 4 4 4 1 3 2 2 ODP 0.11 0 0 0 0 0 0 0 GWP 700 990 910 910 1600 <11 <11 <11 HCFC 141b HFC245fa Mol weight 117 134 148 Boiling point (°C) 33 15 Lambda gas -10C (mW/m.K) 9 Flash point (°C) agents are given in the table. between the three pentane isomers. There are significant differences in boiling point, gas thermal conductivity and polyol solubility, which leads to very different foam properties and processing characteristics. Cyclo/iso pentane mixtures tend to produce the lowest thermal conductivity foams and are preferred in applications such as refrigerators. Cyclopentane is, in certain cases, preferred when local storage regulations are less stringent than for other pentanes. 6 European headquarters Huntsman Everslaan 45 B-3078 Everberg Belgium Telephone +32 2 758 9268 Fax +32 2 758 7268 E-mail rigids_pu@huntsman.com American headquarters Huntsman 10003 Woodloch Forest Drive The Woodlands Texas 77380 USA Telephone +1 281 719 6000 Fax +1 281 719 6054 Asian headquarters Huntsman No. 452 Wen Jing Road Minhang Development Zone Shanghai 200245 Telephone +86 21 2403 7288 Fax +86 21 6462 1234 Huntsman Polyurethanes warrants only that its products meet the specifications agreed with the buyer. Typical properties, where stated, are to be considered as representative of current production and should not be treated as specifications. 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Except where explicitly agreed otherwise, the sale of products referred to in this publication is subject to the general terms and conditions of sale of Huntsman International LLC or its affiliated companies. www.huntsman.com/insulation insulation@huntsman.com Copyright © 2011 Huntsman Corporation or an affiliate thereof. All right reserved. Editor: Kristof Dedecker