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Rigid Isocyanate foams
(MDI) |
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Rigid foams for housing insulation require to meet certain flammability
standard and also cost requirements. This foam utilizes a minimum of
HCFC blowing agent and relies mainly on water for blowing. |
| Formulation Isocyanurate Spray foam Carbon dioxide
and HCFC blown |
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Blowing Agent
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Water
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Water/HFC134a |
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Polyether polyol OH value 380 mg KOH/g Triol (CAS # 25791-96-2) |
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60 |
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Sorbitol propoxylated OH value 380 (CAS # 52625-13-5) |
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30 |
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Silicone surfactant |
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1.5 |
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Tris(2-chloropropyl) phosphate (CAS #
6145-73-9) |
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10 |
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Water |
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2.4-2.7 |
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HCFC-134a blowing agent (1,1,1,2-Tetrafluoroethane,
CAS # 811-97-2 ) |
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0-3 |
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Catalyst DMCHA (N,N-Dimethylaminocyclohexane, CAS #
98-94-2) |
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1.8 |
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Catalyst PMDETA (1,1,4,7,7-Pentamethyldiethylenetriamine, CAS
# 3030-47-5) |
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1.0 |
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Catalyst organotin gelation (Dibutyltin bis(dodecyl
mercaptide,
CAS # 1185-81-5)
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0.2
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| Polymeric crude MDI (CAS #
9016-87-9) NCO index
100 |
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120 |
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Density pcf |
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3.1 |
3.2 |
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k-factor (BTU-in./hr-ft2-°F) |
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0.18 |
0.195 |
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Compressive strength (psi) |
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44 |
42 |
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Dimensional stability, 28 days 100°C |
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-4 |
-1.3 |
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Dimensional stability, 28 days 70°C/97
% relative humidity |
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-3 |
-0.9 |
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ICI Dimvac 14 days, 25°C |
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-8 |
-0.6 |
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Open cell content, % |
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8 |
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The use of water as the only blowing agent produces a foam
with more of a tendency to shrink. Shrinkage can be reduced
with the use of surfactants which produce more open cell
structures. The addition of HCF 134 a requires a slight
increase in catalyst to compensate for the lower processing
temperature. Reduced shrinkage with the blowing agent is a
result of slower diffusion of the blowing agent. |
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Last edited on:
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November 16, 2006
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