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)
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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
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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.
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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.
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European headquarters Huntsman Everslaan 45 B-3078 Everberg Belgium Telephone +32 2 758 9268 Fax +32 2 758 7268 E-mail
[email protected] 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
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Copyright © 2011 Huntsman Corporation or an affiliate thereof. All right reserved. Editor: Kristof Dedecker
