Polyurethanes Blowing agent options for insulation foam ...

1 PolyurethanesBlowing agent options for insulation foamafter hcfc phase outHCFC phase outIn 1987, the Montreal Protocol was signed to protectthe ozone layer by phasing out the production ofa number of substances responsible for ozonedepletion such as CFCs (chlorofluorocarbons) andHCFCs (hydrochlorofluorocarbons). CFCs have beenphased out since 1996 in industrialised countries,and recently in developing of their lower ODP (Ozone Depletion Potential),HCFCs have been an established intermediate alternativeto CFCs. In regions such as the European Union or theUnited States of America, the use of HCFC141b in foamapplications has been banned for almost a decade.

2 In mostdeveloping (article 5) countries and in some industrialised(non article 5) countries, such as the Russian Federation,HCFC141b has been the preferred Blowing agent in the lastdecade. However, in 2007 at the 19th meeting of theMontreal protocol, nations signed up to accelerate thephase-out of HCFCs (see Figure 1). For developing countries,as of 1st January 2013, the consumption of HCFC141bwill be capped and 2 years later, as of 1st January 2015,it will be gradually reduced until 2030. Figure 1: HCFC141b phase out schedule in developing countries100%80%60%40%20%0%2020201520132 0302025204090%65% cap set at 2015 levels;gradual reduction begins in 2015 Mandatory reviewof needfor service tailin tailnNew phase-out shedulenPre Montreal 2007 phase-out shedule3nNon-Article 5 countries (industrialised)nArticle 5 countries (developing) Blowing agent evolutionThe transition process from HCFC141b to alternativeblowing agents has been taking place in most industrialisedcountries in the beginning of the previous decade.

3 As can beseen in Figure 2, various Blowing agent choices are available,depending on technical, regulatory and economical Europe, an estimated 85 to 90% of all insulation foams arecurrently blown with pentane technology, which has an excellenttrack record for both foam performance and safe alternatives for HCFC141b, it is important to considerthe global warming potential (GWP) of replacement blowingagents. Since the Kyoto Protocol identified HFCs as industrialgases requiring emissions control because of their high GWP,several producers have started the development of HFOs(hydrofluoroolefins).

4 HFOs have a very low GWP but availabilityat an industrial scale is expected to take a few years. CFC 11 Not flammableHigh ODPHigh GWPHCFC141bNot flammableMedium ODPHigh GWPHCF lammableZero ODPLow GWPHFCNot flammableZero ODPHigh GWPW aterNot flammableZero ODPLow GWPHFONot flammableZero ODPLow GWPI sopentaneNormal pentaneCyclopentane245fa365mfc/227ea134a Figure 24 Alternatives to HCFC141bThe table shows the properties of alternativeblowing agents relative to is no "drop-in" replacement forHCFC141b that combines ease of use andprocessing alongside low operating has acquired a broad technicalexpertise with all Blowing agent alternatives.

5 Both by the application development teamslocated in Ternate (Italy) and by regionalteams implementing dedicated solutions of other Blowing agents relative to HCFC141bBlowing agent priceLowerMuch higherNone5-10% higher5-10% higher 20% higher5% lower densityfeasibleSimilar5-10% higherExplosion proofequipment neededAlmost noneAlmost noneLowLong term solutionHighLowLong term solutionLimited solubilityin polyolsComparableWorse surface andadhesionFoam thermalconductivityFoam densityMachine adjustmentsGWPFoam processingPentaneHFC245faHFC365mfc/227ea Water5 PENTANEis a cheap Blowing agent , which produces lowdensity foams with low thermal conductivity and goodproperties.

6 However, the investment to handle a flammableblowing agent is not always justifiable, especially for small foamproducers. In most cases, pentane is added to the polyolblend at the customer s premises to avoid the transportationof a flammable polyol blend. In continuous operations(lamination), pentane is added in line, just before the mixinghead. In discontinuous operations, pentane is pre-blendedto the polyol blend with suitable HFC245facan be implementedeasily as replacements of HCFC141b without major changesin foam processing. In view of the high cost of HFCs,formulations have been finetuned towards an optimum cost /performance ratio.

7 HFCs are typically added by the polyolblend supplier and transported to the customer as a non-flammable polyol blend. The pressure build-up of HFCcontaining polyol blends is normally limited, but appropriatepackaging of the polyol blend needs to be chosen as afunction of HFC content, HFC compatibility with the polyolblend and storage DIMETHOXYMETHANEare potential Blowing agents for rigid foam, but currentindustrial experience is limited in the European Blowing agents can be interesting options incertain cases, particularly in combination with one ofthe aforementioned obviously a cheap Blowing agent but haslimitations for both foam processing and final foam density is substantially higher and good adhesionand foam surface quality are more difficult to foams also have a higher thermal foams, which are not protected by diffusiontight facings, are subject to a gradual increase of thermalconductivity over time, much more than is the case forfoams produced using a physical Blowing agent .

8 Blowing agent choice per applicationIn contrast to HCFC141b, where one Blowing agent was chosenfor all rigid foam applications, different Blowing agent choiceswill be available after the hcfc phase out. Pentane is generallypreferred when the foam consumption is high ( in board orpanel lamination). In figure 3, the Blowing agent choice inindustrialised countries is schematically three corners of the triangle represent a situation wherea market segment has been entirely converted to pentane,HFC or to a fully water blown solution. Positions within the triangleindicate the relative amount of producers within a segment,that have chosen any of the three Blowing agent options .

9 Physical properties of Blowing agentsThe physical properties of blowingagents are given in the is interesting to note the differencesbetween the three pentane are significant differences in boilingpoint, gas thermal conductivity and polyolsolubility, which leads to very different foamproperties and processing pentane mixtures tend to producethe lowest thermal conductivity foamsand are preferred in applications such asrefrigerators. Cyclopentane is, in certaincases, preferred when local storage regulationsare less stringent than for other 141bHFC245faHFC365mfcHFC365mfc/227ea 93/7 HFC 134aCYCLOPENTANENORMALPENTANEISOPENTANEM ol weightBoiling point ( C)Lambda gas-10C ( )Flash point ( C)Solubility inpolyols(1=low, 5=high)

10 <11<11<11 HCHFCWATERB oard / panel laminationEuropean refrigerator / freezerSpray technologyFigure 36 Pre-insulated pipesDiscontinuous panels, display units, etcNorth American refrigerator / freezerEuropean headquartersHuntsmanEverslaan 45B-3078 EverbergBelgiumTelephone +32 2 758 9268 Fax+32 2 758 headquartersHuntsman10003 Woodloch Forest DriveThe WoodlandsTexas 77380 USAT elephone +1 281 719 6000 Fax +1 281 719 6054 Asian headquartersHuntsmanNo. 452 Wen Jing RoadMinhang Development ZoneShanghai 200245 Telephone +86 21 2403 7288 Fax +86 21 6462 1234 Huntsman Polyurethanes warrants only that its products meetthe specifications agreed with the buyer.