ABSTRACT
TITLE:
Blowing Agent Blends - The New Norm
Author(s):
John A. Murphy, Foam Supplies, Inc.
ABSTRACT:
With the cost of each successive generation of physical foam blowing agents climbing ever higher, the
urethane world is turning to physical blowing agent blends for recourse.
Urethanes have long used blends, such as CFC-11/ CFC-12 for better flow properties, or HFC-365mfc/
HFC-227ea to mitigate flammability. More recently HCs [nC5/iC5/cC5] have been blended with one
another for improved solubility, flow, and thermal properties. These same HCs have been used with HFCs
to cut cost, although leading to some flammability issues.
Most recently DuPont has been investigating azeotropic mixtures of FEA1100 with HCs, methylal,
Ecomate and certain HFCs, to improve properties and reduce costs. Arkema and Honeywell are expected
to follow suit.
The purpose of this paper is to show how select blends of Ecomate with specific other physical blowing
agents can greatly enhance thermal properties, maintain very competitive cost structures, and remain
environmentally benign.
4387 Rider Trail N. | Earth City, MO 63045 | 1.800.325.4875 | +1.314.344.3330
www.foamsupplies.com | www.ecomatesystems.com
BLOWING AGENT BLENDS – THE NEW NORM
JOHN MURPHY
FOAM SUPPLIES, INC
4387 N. Rider Trail
Earth City, MO 63045 USA
ABSTRACT:
With the cost of each successive generation of physical foam blowing agents climbing ever higher, the
urethane world is turning to physical blowing agent blends for recourse.
Urethanes have long used blends, such as CFC-11/ CFC-12 for better flow properties, or HFC-365mfc/
HFC-227ea to mitigate flammability. More recently HCs [nC5/iC5/cC5] have been blended with one
another for improved solubility, flow, and thermal properties. These same HCs have been used with
HFCs to cut cost, although leading to some flammability issues.
Most recently DuPont has been investigating azeotropic mixtures of FEA1100 with HCs, methylal,
Ecomate and certain HFCs, to improve properties and reduce costs. Arkema and Honeywell are
expected to follow suit.
The purpose of this paper is to show how select blends of Ecomate with specific other physical blowing
agents can greatly enhance thermal properties, maintain very competitive cost structures, and remain
environmentally benign.
BACKGROUND:
Urethane foams were first blown with water. This was in the time before surfactants, when prepolymers were made and used to improve the miscibility of the polyol and the isocyanate, lest they
phase separate before reacting.
Then in the late 1950’s, DuPont experimented with their newly developed chlorofluorocarbons [CFCs]
and found that CFC-11 [trichlorofluoromethane] had very good solubility with most polyols, cut the
viscosity of isocyanate prepolymers, and made a very controllable reaction [density and reactivity] foam
with surprisingly good thermal conductivity.
With the introduction of surfactants [surface active agents] in the late ‘60s, this urethane chemistry
started to become an industry. Foams were much easier to produce because, for the most part, prepolymers were no longer needed. As it grew, the market began to segment into specific sectors, such as
spray foam, and pour-in-place foams. To help the market grow, the raw material manufacturers [polyol,
isocyanate, catalyst, fire retardant, and surfactant alike] freely distributed formulations demonstrating
how best to use their products.
Everyone quickly recognized that CFC-11 gave superior thermal properties to those obtained with
water, and used less isocyanate. The refrigeration industry soon discovered that a small amount of
water blended with the CFC-11 in the polyol mix gave superior thermal properties [because it formed
much finer cells]. They kept this informatiion close to their chests. This was potentially the first
commercial blowing agent blend.
Early on it was also discovered that the use of CFC-12 [difluorodichloromethane] could be used to form
a froth foam. This was deemed superior to CFC-11 blown systems – not so much in physical properties,
but in the ability to fill a cold mold, or a poorly fitting mold as well. These differences in flow
characteristics made R-12 blown foams more desirable, if less thermally efficient.
In spray foam, CFC-11 was the hands down favorite because it produced excellent foams, both
physically and thermally. Like any other urethane realm, the spray boundaries were constantly being
pushed. In this case, the ability to spray on colder and colder substrates was the target. Eventually even
the hottest [most highly catalyzed] systems failed to overcome the densification induced by the cold
substrate. This seemed an insurmountable barrier until a small amount of CFC-12 [and eventually R-22]
was introduced into the system along with the R-11, allowing the foam to rise off the substrate and
finish its reaction profile in a normal fashion. This [0.5 – 1.5% R-12 in R-11] blend allowed the spray
foamers to work longer in the season, and improved their competitiveness with other not-in-kind
insulations.
In the transition to HCFC-141b, formulators initially had difficulty with the greater solubility of 141b in
comparison to CFC-11. They overcame this, in part, by using higher water contents with the HCFC. Thus
blending blowing agents [BAs] continued.
In the transition to HFCs, the use of higher water contents continued to mitigate the higher cost of
these products. In the particular case of HFC-365mfc – it was soon learned that it had a flammability
issue as a neat material. So a 93/7% blend with HFC-227ea was offered to overcome this Achilles heel.
When hydrocarbons [HCs] hit the scene, the initial candidate was normal pentane [nC5]. It was much
different [poorer] in solubility than the CFCs or the HCFCs then used, so much so that accommodations
had to be made to make it work. This meant reformulation - to find better soluble raw materials, and
the incorporation of stronger surfactants to help emulsify the mixtures. Even so, this technology can
only be used under extremely controlled conditions – such as lamination and refrigeration lines.
Additionally, nC5 does not have a low enough boiling point [36⁰C] to warrant low catalyst levels, so
blends were made with iso-pentane [iC5, BP=28⁰C] to lessen cost of catalysts and improve reaction
profile. Others, looking for improved thermal values, have converted to cyclopentane [cC5, BP 49⁰C], or
iC5/cC5 blends. This is not to say that the thermal properties of HC blends are superior to those of
HCFCs or HFCs. CFCs were superior to HCFCs and HFCs. To date, each subsequent transition has shown
thermal values inferior to the generation preceding it.
The point is that BA blends have long been used to enhance properties, modify reaction rates, mitigate
flammability, or to reduce costs. The PU industry will continue to investigate blends with the
forthcoming HFOs.
BLENDS – THE NEW NORM
Anticipating higher costs [or flammability issues], the manufacturers of the much anticipated HFOs are
currently investigating blends with their candidates. Arkema and Honeywell are currently shrouding
their respective candidates (which seem to be internal blends [undisclosed] of an HFO [or HFOs] and a
halocarbon for non-flammability).
DuPont, who has recently identified their FEA1100 candidate as HFO-1336mzz, is looking at other
materials with which to blend to optimize properties and potentially reduce costs. In a recent paperi,
they disclosed work they were doing with ecomate, methylal, and certain hydrocarbons. There they
describe the benefits of selecting the proper blend of water and FEA-1100 to give improved k-factors
and reduced HFO content. In addition, in the same paper (Figure 1 below), they describe benefits of
reduced thermal properties and improved flammability in blends of the HFO with methylal, iC5, cC5, or
ecomate.
Ecomate and cC5 showed the lowest k-factors in their study (both 19.7 kW/m⁰K at 23.9 ⁰C).
Effect of FEA-1100 Blends
K-factor (mW/mK @ 23.9 C
25
24
23
neat
22
FEA blend
21
20
19
cC5
iC5
MF
ML
Figure 1: Effect of FEA-1100 Mixtures with Pentanes, Methyl Formate, and Methylal [DuPont data]
The above results make perfect sense if one considers the lambda values of the neat materials in the
blends [Table 1]. Ecomate has the lowest lambda of these materials. In addition, it has the lowest
molecular weight [so less needs to be used to reach a given density], has better environmental
properties, and better flammability characteristics.
Table 1: Comparison of Physical & Environmental Properties of Neat Physical Blowing Agents.
BA
Ecomate
(MF)
Methylal
(ML)
iC5
nC5
cC5
UNITS
MW
60
76.1
72
72
70
g/mol
BP
32
42.3
28
36
49
⁰C
λ, at 20 ⁰C
10.7
11-14
14
14
11
mW/m⁰K
SpGr
0.982
0.86
0.624
0.63
0.75
g/l
MIR [Smog]
0.06
1.04
0.5
0.46
0.78
ETHANE=
0.28
GWP
<1.5
<1.5
11
11
11
CO2=1
FLASH Pt
-19
-18
-51
-49
-37
⁰C
LFL
5
1.6
1.4
1.5
1.1
vol%
UFL
23
17.6
7.6
7.9
8.7
vol%
16.2
25.1
46.7
49.7
46.9
MJ/g
Ht COMB
For instance, ecomate has the lowest MIR values of any on the list [MIR values must be less than
ethane = 0.28 to be deemed to not contribute to smog in the US], as well as the highest LFL [less danger
of burning] and the lowest heat of combustion [safer because it gives off less energy if burned – this is
because it is partially “burned” already – containing 53 wt% oxygen per mole]. Ecomate does not
contribute to fire load, requiring no additional fire retardant to achieve equivalent fire resistance when
switching from another BA, such as from HCFC-141b. Ecomate can also be used up to 6wt% in polyol
mixtures and be shipped without red Fire Placards.
Methylal is more flammable, in part because it contains but 42wt% oxygen in its molar backbone. It
could also be the biggest contributor to smog [with the highest MIR value of those materials in Table 1].
And it can only be accommodated up to 2 wt% in polyol mixtures before fire placards are required. Nor
does it have good thermal properties, as demonstrated by the DuPont work above [Fig. 1].
Hydrocarbons certainly contribute to fire load, and require up to 20 % more fire retardant in a
formulation to achieve similar fire ratings as other non-flammable blowing agents. They also contribute
to smog, and would not be acceptable in certain ‘non-containment’ areas in the US. They are flammable
enough [by themselves] not to be used in spray foams. It is doubtful that the 69% fluorine content of
HFO 1336mzz would be enough to overcome the static-prone HCs when used in spray foam. Ecomate
has a very low static build [a high electrical conductivity = 1.92x10^9 pS/m], and with its lower heat of
combustion and high LFL, enables it to be used in spray foams.
Pressure, [MJ/g]
Figure 2: Relative Pressure developed on burning Various Blowing Agents
50
45
40
35
30
25
20
15
10
5
0
46.9
MF
25.1
cC5
ML
16.2
141b
7.9
00
0
0
5
0
0
10
00
15
0
20
25
Vol% in Air
DuPont did additional work with cC5 to optimize the blend but published no better results than those
obtained with ecomate above (19.7 kW/m⁰K at 23.9 ⁰C). Similar work with ecomate should improve
solubility, have less flammability risk, and be more environmentally friendly [no smog issues] than
results obtained with HCs. Why? Because ecomate has very good solubility for all raw materials used to
make foams [better even than 141b]. Less flammable because it has a higher flash point than the other
materials, a higher LFL and a lower heat of combustion [Figure 2]. More benign to the atmosphere
because it has a negligible GWP, and is non-smog producing [having an extremely low MIR].
Work done by Foam Supplies with Ecomate blends suggest that thermal values superior to those
above can be obtained without the higher cost of an HFO. These data have been obtained from actual
laminate board productionii. Using an ecomate/iC5/cC5 blend, we were able to obtain 19.3 mW/m⁰K
at 23.9⁰C and 16.9 at -6.7⁰C. Of course this blend is flammable, but for laminator or refrigeration lines
already geared for pentanes, this should be no problem. We have burned these panels in our MiniTunnel, and have obtained 25 Flame Spread and extremely low [<200] smoke values [Table 2].
Ecomate economics are excellent because it is competitive with other BAs on the market, and with its
lower MW less is required to achieve comparable densities. Blowing agent blends have truly become
the new norm!
Table 2: Commercial Boardstock blown with Pentane and Ecomate blends
PROD TRIAL
Dens, pcf
CCC, %
CONTROL ECOMATE
1.75
1.97
98.5
94.6
∆%Vol, 7days
COLD
WET
DRY
0.98
4.11
3.03
-0.7
5.06
4.35
CS //, psi
20.3
12.9
Lambda, 23.9⁰C
21.3
19.8
19.3
16.9
30
400
25
180
Lambda, -6.7°C
FS
Smoke
CONCLUSIONS:
1. Blowing agent BLENDS have long been used in this industry to improve performance, properties,
or economics.
a. Water was added to CFC-11 to nucleate finer cells and improve thermal properties.
b. More water was added to HCFC-141b to mitigate stronger solubility.
c. A small amount of gaseous BA was added to Liquid BA to allow spray formulations to be
applied to cold substrates.
d. Most recently, blends of HCs are being used to improve solubility, flow and thermal
properties of laminator and refrigeration line foams.
2. With the anticipated arrival of the HFO blowing agents, blends will become the norm to:
a. Lower system costs, improve properties [especially thermal], and improve performance.
3. Ecomate blends can produce foams with
a. Lower lambda values,
b. Good economics, and
c. Good fire properties
i. Both in-container, and
ii. In foams.
BIOGRAPHY
John A. Murphy
John received his BS in Chemistry in 1965. During his 35
years researching urethanes he has worked for [among
others] ARCO Chemical and Arkema, where he
introduced HCFC-141b and HFC-365mfc to the industry.
Currently employed by FSI, he is responsible for New
Product Development - Ecomate.
REFERENCES:
i
Loh, G., Robin, M., Creazo J., “Further development of FEA-1100- a zero ODP and low GWP foam expansion
th
agent”, Proceedings of 13 Blowing Agents and Foaming Processes Conference, Dusseldorf, Germany (2011).
ii
Murphy, J., Modray, D., “The Benefits of Optimization in Ecomate Blown Insulating Foams”, CPI Conference
Proceedings, Polyurethanes 2011, Nashville, TN.
A BRIEF BA HISTORY
In the beginning… Water
CFCs
 Liquid CFC-11
 Froth CFC-12
 Blends – allowed low temp applications
 Lower thermals - With H2O
HCFCs
 141b – used water to reduce solubility, shrinkage
A BRIEF BA HISTORY
HFCs
 Use water to mitigate higher costs
 365mfc – used HFC-227ea blends to reduce
flammability
HCs
 Only in controlled environments
 nC5
With iC5 – to improve reaction profile, reduce cats
With cC5 – to improve thermals
A BRIEF BA HISTORY
THERMAL PROPERTIES
 Each Generation was poorer than the last
Physical
Blowing Agent
average
K-Factor
Lambda
CFC-11
0.11
15.8
HCFC- 141b
0.14
20.1
HFC-245fa
0.145
20.9
 Each Generation was more Costly !
A BRIEF BA HISTORY
HFOs
 HFO 1233zd-E [Honeywell Solstice LBA] - MW 130
 HFO 1233zd-E [Arkema HBA-2]
- MW 130
 HFO 1336mzz-Z [DuPont’s FEA1100]
- MW 164
A BRIEF BA HISTORY
HFOs
 HFO 1233zd-E [Honeywell Solstice LBA]
 HFO 1233zd-E [Arkema HBA-2]
 HFO 1336mzz-Z [DuPont’s FEA1100] - blends
 Optimize properties
 Reduce costs
 Working with
 HCs,
 Ecomate,
 Methylal,
 Water
EFFECT OF FEA-1100 BLENDS
DUPONT DATA
K-factor (mW/mK @ 23.9 C
25
24
23
neat
22
21
20
21.1
20.9
19.7
19.7
19
cC5
iC5
MF
ML
FEA blend
EFFECT OF FEA-1100 BLENDS
K-factor (mW/mK @ 23.9 C
DUPONT DATA
23
22.5
22
21.5
21
20.5
20
19.5
19
21.1
20.9
19.7
cC5
19.7
iC5
MF
ML
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
Ecomate Methylal
(MF)
(ML)
iC5
nC5
cC5
UNITS
MW
60
76.1
72
72
70
g/mol
BP
32
42.3
28
36
49
⁰C
10.7
11-14
14
14
11
mW/m⁰K
0.982
0.86
0.624
0.63
0.75
g/l
λ, at 20 ⁰C
SpGr
MIR [Smog]
0.06
0.94
1.45
1.31
2.39
ETHANE=
0.28
GWP
<1.5
<1.5
11
11
11
CO2=1
-19
-18
-51
-49
-37
⁰C
5
1.6
1.4
1.5
1.1
vol%
53.3
42.1
0
0
0
Wt%
16.2
25.1
46.7
49.7
46.9
MJ/g
FLASH Pt
LFL
% Oxygen
Heat of
COMBUSTION
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
MF
physical
ML
60
76.1
BA
MW
iC5 nC5 cC5
72
72
70
UNITS
g/mol
Lowest MW – less needed
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
MF
physical
ML
MW
60
76.1
72
72
70
g/mol
BP
32
42.3
28
36
49
⁰C
BA
iC5 nC5 cC5
UNITS
Lowest MW – less needed
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
MF
physical
ML
MW
60
76.1
72
72
70
g/mol
BP
λgas ,
32
42.3
28
36
49
⁰C
BA
at 20 ⁰C
10.7
11-14
iC5 nC5 cC5
14
14
11
UNITS
mW/m⁰K
Lowest MW – less needed
Lowest Lambda
– more efficient
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
MF
physical
ML
MW
60
76.1
72
72
70
g/mol
BP
λgas ,
32
42.3
28
36
49
⁰C
BA
iC5 nC5 cC5
UNITS
at 20 ⁰C
10.7
11-14
14
14
11
mW/m⁰K
SpGr
0.98
0.86
0.62
0.63
0.75
g/l
Lowest MW – less needed
Lowest Lambda
– more efficient
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
MF
physical
ML
MW
60
76.1
72
72
70
g/mol
BP
λgas ,
32
42.3
28
36
49
⁰C
BA
iC5 nC5 cC5
UNITS
at 20 ⁰C
10.7
11-14
14
14
11
mW/m⁰K
SpGr
0.98
0.86
0.62
0.63
0.75
g/l
Ecomate – Low cost, less needed, more efficient !
Lowest MW – less needed
Lowest Lambda
– more efficient
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
Ecomate
(MF)
ML
iC5
nC5
cC5
UNITS
environmental
GWP
<1.5
<1.5
11
11
11
CO2=1
Negligible
GWP
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
Ecomate
(MF)
ML
iC5
nC5
cC5
UNITS
environmental
GWP
<1.5
<1.5
11
11
11
MIR [Smog]
0.06
0.94
1.45
1.31
2.39
CO2=1
ETHANE=
0.28
Negligible
GWP
No SMOG
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
Ecomate
(MF)
BA
ML
iC5
nC5
cC5
UNITS
environmental
GWP
<1.5
<1.5
11
11
11
MIR [Smog]
0.06
0.94
1.45
1.31
2.39
Ecomate – more Environmentally Friendly !
CO2=1
ETHANE=
0.28
Negligible
GWP
No SMOG
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
MF
ML
iC5
nC5
cC5
UNITS
-18
-51
-49
-37
⁰C
flammability
FLASH Pt
-19
LESS HAZARD
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
MF
ML
iC5
nC5
cC5
UNITS
-19
-18
-51
-49
-37
⁰C
LESS HAZARD
5
1.6
1.4
1.5
1.1
vol%
LESS HAZARD
flammability
FLASH Pt
LFL
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
MF
ML
iC5
nC5
cC5
UNITS
-19
-18
-51
-49
-37
⁰C
LESS HAZARD
5
1.6
1.4
1.5
1.1
vol%
LESS HAZARD
53.3
42.1
0
0
0
Wt%
LESS HAZARD
flammability
FLASH Pt
LFL
% Oxygen
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
MF
ML
iC5
nC5
cC5
UNITS
-19
-18
-51
-49
-37
⁰C
LESS HAZARD
5
1.6
1.4
1.5
1.1
vol%
LESS HAZARD
53.3
42.1
0
0
0
Wt%
LESS HAZARD
16.2
25.1
46.7
49.7
46.9
MJ/g
LESS HAZARD
flammability
FLASH Pt
LFL
% Oxygen
Heat of
COMBUSTION
PROPERTIES OF SOME NEAT
PHYSICAL BLOWING AGENTS
BA
MF
ML
iC5
nC5
cC5
UNITS
-19
-18
-51
-49
-37
⁰C
LESS HAZARD
5
1.6
1.4
1.5
1.1
vol%
LESS HAZARD
53.3
42.1
0
0
0
Wt%
LESS HAZARD
16.2
25.1
46.7
49.7
46.9
MJ/g
LESS HAZARD
flammability
FLASH Pt
LFL
% Oxygen
Heat of
COMBUSTION
Ecomate – Less Hazardous !
Pressure, [MJ/g]
RELATIVE PRESSURES ON BURNING
50
45
40
35
30
25
20
15
10
5
0
46.9
MF
cC5
ML
141b
25.1
16.2
7.9
00
0
0
5
0
0
00
10
15
Vol% in Air
0
20
25
LAMINATE BOARD TRIALS
Comparing ECOMATE BLENDS to PENTANE BLENDS
SUPERIOR RESULTS
Thermals and Burns
THREE FULL-SCALE TRIALS - Replicated Results
BOARDSTOCK WITH
PENTANE & ECOMATE BLENDS
PRODUCTION TRIAL
Lambda, 23.9⁰C
Lambda, -6.7°C
PENTANE
21.3
19.8
ECOMATE
19.3
16.9
BOARDSTOCK WITH
PENTANE & ECOMATE BLENDS
PRODUCTION TRIAL
Lambda, 23.9⁰C
Lambda, -6.7°C
FS
Smoke
PENTANE
21.3
19.8
ECOMATE
19.3
16.9
30
400
25
180
BOARDSTOCK WITH
PENTANE & ECOMATE BLENDS
PRODUCTION TRIAL
Lambda, 23.9⁰C
Lambda, -6.7°C
FS
Smoke
PENTANE
21.3
19.8
ECOMATE
19.3
16.9
30
400
25
180
FEA -1100
19.7
BOARDSTOCK WITH
PENTANE & ECOMATE BLENDS
PRODUCTION TRIAL
Lambda, 23.9⁰C
Lambda, -6.7°C
FS
Smoke
PENTANE
21.3
19.8
ECOMATE
19.3
16.9
30
400
25
180
FEA -1100
19.7
BOARDSTOCK WITH
PENTANE & ECOMATE BLENDS
PRODUCTION TRIAL
Lambda, 23.9⁰C
Lambda, -6.7°C
FS
Smoke
PENTANE
21.3
19.8
ECOMATE
19.3
16.9
30
400
25
180
FEA -1100
19.7
You can get very low values w/o HFOs
CONCLUSIONS
BA BLENDS have long been with us
To improve physical properties:
Flow
Adhesion
Thermal Conductivity
Solubility
Flammability
To reduce costs
BLENDS – THE NEW NORM
• Because there is no perfect product
• HFOs will be blended also
• Blends w Ecomate will be BEST Choice!
Ecomate BLENDS can be:
 More
Thermally Efficient,
 More
Environmentally Benign,
 Less
Flammable,
 More
Economical
Because neat ecomate already has these properties!
ecomate by FOAM SUPPLIES
THANK YOU !