DuPont Formacel. FEA-1100 has low vapor thermal conductivity, providing excellent insulation performance.

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1 DuPont Formacel DEVELOPMENT PROGRAM UPDATE FOR LOW GWP FOAM EXPANSION AGENT W H I T E P A P E R Gary Loh, Joseph A. Creazzo, Mark L. Robin DuPont Fluorochemicals ABSTRACT Polyurethane foams are widely employed for thermal insulation in the appliance and construction industries. Foam expansion agents (FEAs or blowing agents) are critical for providing the insulation performance of these foams. CFC-11 and HCFC-141b were once the FEAs of choice, but their use is being phased out due to their ozone depletion potential (ODP). The current zero ODP FEAs include hydrofluorocarbons (HFCs) and hydrocarbons, but these agents face further challenges. Both HFCs and hydrocarbons are characterized by increased thermal conductivities compared to both the HCFCs and CFCs, resulting in inferior insulation performance, and HFCs such as HFC-245fa and HFC-365mfc have global warming potentials (GWPs) near 1,000. In addition, the low boiling point of HFC-245fa and the flammability of hydrocarbons and HFC-365mfc present significant challenges to processing and handling. With the increased focus on global warming potential and energy efficiency, the industry is looking for a foam expansion agent that is environmentally sustainable with superior insulation performance. DuPont Fluoroproducts introduces a novel foam expansion agent, FEA-1100, for polyurethane foams. FEA-1100 has zero ODP and low GWP. It is also non-flammable and a stable liquid at ambient temperature. This paper discusses the properties and characteristics of FEA-1100 for PUR applications such as appliance, pour-in place, spray and PIR boardstock. We will discuss recent results in toxicity evaluation, material compatibility, and foam properties, particularly insulation performance. INTRODUCTION In recent years concerns over climate change have intensified, and as a result the industry is seeking foam expansion agents not only characterized by zero ODP, but also by lower global warming potentials (GWPs) compared to those of the HFCs. In addition, the increased demand for energy efficiency also requires the FEAs to have low vapor thermal conductivity to produce foams with superior insulation performance. Taking these requirements into consideration, DuPont Fluoroproducts has developed a novel Fourth-Generation foam expansion agent FEA We report here further application studies on FEA-1100, including material compatibility and the performance of FEA-1100 with the major types of polyols employed for the manufacture of polyurethane foams. The results indicate that in addition to being characterized by improved environmental properties, FEA-1100 also provides superior insulation performance in foam applications. Data obtained to date also suggest that FEA-1100 can serve as a drop-in to replace other types of liquid FEAs with low conversion costs. PROPERTIES OF FEA-1100 FEA-1100 has an excellent environmental profile. It is characterized by zero ozone depletion potential and low global warming potential. Recent estimates indicate that FEA-1100 has a short atmospheric lifetime of approximately 16 days. FEA-1100 has low vapor thermal conductivity, providing excellent insulation performance. FEA-1100 is non-flammable in standard ASTM tests. Testing according to ASTM E 681 Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases) indicated non-flammability at temperatures of 60 C and at 100 C. The non-flammability enables the safe use of FEA-1100 in a broad range of applications.

2 FEA-1100 is a stable liquid at room temperature, with a boiling point > 25 C. This eliminates the handling and processing issues associated with the use of lower boiling FEAs such as HFC-245fa, allowing optimal FEA level in formulations to provide desired foam properties. Table 1 lists the properties of FEA-1100 and other FEAs. As shown in Table 1, the previous FEA transition sacrificed some desirable characteristics (low vapor thermal conductivity, high boiling point, and nonflammability) in exchange for improved environmental properties. FEA-1100 provides improved environmental properties while maintaining the desired characteristics of low vapor thermal conductivity, non-flammability and a boiling point above 25 C. Table 1: Properties of Foam Expansion Agents CFC-11 HCFC-141b HFC-245fa HFC-365mfc Isopentane FE-1100 ODP GWP (100 year ITH) e gas 25 C mw/mk Flash Point non none none C -51 C none bp C >25 2 TOXICITY ASSESSMENT Toxicological testing performed to date indicates that FEA-1100 can be safely used in foam expansion applications. Table 2 summarizes these toxicity assessments. Further toxicological testing is underway to evaluate the risks of longer term exposure. ALC and LC-50 Skin Irritation Test Mutagencity-Ames Chromosomal Aberration Cardiac Sensitization Table 2: FEA-1100 Toxicological Assessments Very low acute toxicity Non-irritating Non-mutagenic Results No genetic material damage when tested in bacterial and mammalian cell cultures Favorable cardiac sensitization potential profile 28 day repeated inhalation Favorable repeated inhalation profile COMPATIBILITY WITH METALS Compatibility tests for FEA-1100 with metals were performed in sealed tubes. Metal coupons (copper, brass, carbon steel, stainless steel and aluminum) were immersed in FEA-1100 and heated in an oven for 14 days at 100 C (212 F), and changes in weight and appearance of the metal coupons were recorded. The liquid solutions were also evaluated for appearance and decomposition products such as fluoride. As shown in Table 3, FEA-1100 is compatible with metals commonly employed in polyurethane foam processing. While these simple exposure tests help screen effects on materials of construction, the final materials selection should include testing more specific to the application. Metal Coupons Table 3: Metal Compatibility 2 Weeks Exposure to FEA-1100 at 100 C (212 F) Metal Coupon Weight Metal Coupon Appearance FEA Solution Appearance FEA Solution Analysis Stainless Steel No weight change No sign of corrosion Clear No fluoride detected** Carbon Steel No weight change No sign of corrosion Clear No fluoride detected** Copper No weight change No sign of corrosion Clear No fluoride detected** Brass No weight change No sign of corrosion Clear No fluoride detected** Aluminum No weight change No sign of corrosion Clear No fluoride detected** **Detection limit = 0.5 ppm 2

3 3 COMPATIBILITY WITH PLASTICS Plastics compatibility tests were performed by exposing plastic materials to FEA-1100 at room temperature for two weeks. Weight, volume and hardness before and after the exposure were measured. Observations of changes are summarized in Table 4, which indicates that FEA-1100 is compatible with commonly employed plastics. As always, verifying compatibility using actually fabricated parts under end-user conditions is advised as the performance of plastics is affected by polymer variations, compounding agents, fillers and molding processes. Table 4: Plastic Compatibility 2 Weeks Exposure to FEA-1100 at Room Temperature Symbol Material Brand % Weight % Volume % Hardness ABS Acrylonitrile-butadiene-styrene Cycolac EX58-0.1% -0.6% 0.0% HIPS High Impact Polystyrene 0.3% -0.4% -2.9% PET Poly(ethylene terephthalate) Rynite 0.0% 0.7% -1.2% PS Polystyrene Styron -0.4% 0.9% 0.0% PVC Polyvinyl Choloride Bakelite 0.0% 0.0% 0.0% PTFE Fluorocarbon(PTFE) Teflon 1.1% 0.3% -17.2% ETFE Fluorocarbon(ETFE) Tefzel 0.7% 0.0% 12.9% Lonomer Suryln 0.3% 0.0% 1.9% POM Acetal Delrin 0.1% -1.2% -1.3% PC Polycarbonate Tuffak 0.0% -0.6% 0.0% PEEK Polyetheretherketone Victrex 0.0% 0.2% 0.0% Polyarylate Arylon 0.2% -0.2% -4.4% LCP Polyester Xydar 0.0% -0.4% -1.5% Nylon 6/6 Zytel % -0.5% 3.1% PEI Polyetherimide Ultem -0.1% 0.0% 0.0% Polyaryl sulfone Radel -0.2% 0.3% 0.0% PVDF Poly(vinylidene fluoride) Kynar 0.1% -0.3% 0.0% PP Polypropylene Tenite 0.3% -0.5% 0.0% LCP Zenite -0.1% -0.9% 0.0% HDPE High Density Polyehtylene Alathon 0.0% 0.3% 3.3% Phenolic Duzez 0.0% -0.1% 1.2% COMPATIBILITY WITH ELASTOMERS Elastomeric materials were exposed to FEA-1100 at room temperature for 2 weeks, and changes in volume, weight and hardness were measured before and after the exposure. Table 5 provides a summary of results which indicate that FEA-1100 is compatible with commonly employed elastomers. While these simple exposure tests help screen effects on materials of construction, final materials selection should include testing more specific to the application. 3

4 4 Table 5: Elastomer Compatibility 2 Weeks Exposure to FEA-1100 at Room Temperature Symbol Material Brand % Weight % Volume % Hardness NR Natural Rubber Natural Rubber 4.4% 1.9% 0.0% CR Polychloroprene Neoprene W 0.8% 0.1% 0.0% NBR Acrylonitrile Butadiene BUNA N 15.3% 2.6% -13.6% CSM Chlorosulfonated Polyethylene Hypalon % 0.8% -1.3% FFKM Fluoroelastomer Kalrez 7.9% -3.4% -2.9% T Polysulfide THIOKOL FA 0.3% 6.7% -6.1% IIR Isobutylene Isoprene Butyl Rubber 0.3% 13.1% -13.3% EPDM Hydrocarbon (Ethylene-Propylene Terpolymer) Nordel 1.4% 5.5% -7.1% SOLUBILITY IN POLYOLS One of the important considerations in using a new FEA in polyurethane (PUR) and polyisocyanurate (PIR) foams is its solubility with the foam system polyols. The solubility of FEA-1100 in polyols was tested at 21 C and at 50 C using commercially available polyols from several manufacturers. FEA-1100 was added to the polyols in 5% by weight increments, shaken to mix, and allowed to settle at test temperatures. The addition of FEA-1100 was repeated until the FEA weight percent reached 50% or until FEA-1100 no longer dissolved in the polyol and formed a separate layer. The maximum weight % of FEA in polyols for a single phase mixture is listed in Table 6, which demonstrates that FEA-1100 exhibits good solubility in a wide range of polyols. Polyol Type Polyethers Table 6: FEA-1100 Solubility in Polyols OH# (mg KOH/g) Weight % in Polyols for Single Phase Mixture (21 C) Weight % in Polyols for Single Phase Mixture (50 C) Amine Sucrose/amine Sucrose/glycol Sucrose/glycerine Sorbitol Mannich-base Polyesters VAPOR PRESSURE IN POLYOLS FEA-1100 vapor pressure tests in various polyols were performed at 50 C since FEA-1100 has very low vapor pressure at room temperature. The vapor pressure of FEA-1100 increases with its concentration in polyols and reaches a maximum as the solubility limit is approached. As shown in Figure 1, FEA-1100 vapor pressure at 50 C is well below the typical drum pressure rating of 22 psig. Good solubility and low vapor pressure allow higher FEA-1100 levels to be employed in formulations providing optimal foam properties. 4

5 5 Vapor pressure (psig) FEA-1100 Vapor Pressure at 50 o C % 10% 20% 30% 40% 50% FEA-1100 wt% in polyols Polyether Polyester Drum pressure limit Figure 1. FEA-1100 Vapor Pressure in Polyether and Polyester Polyols FEA-1100 IN MANNICH-BASE POLYETHER FOR SPRAY FOAM APPLICATION Mannich-base polyether polyols are typically employed in spray foam applications. In these tests, the effect of the FEA level was evaluated in a spray foam formulation optimized for HFC-245fa. Equimolar quantities of FEAs and water (CO2) were used for comparison. FEA-1100 was first substituted for HFC-245fa in the formulation using low levels of HFC-245fa. The FEA levels were then increased to high levels as typically employed in HCFC-141b formulations. Foams produced using high and low FEA levels were analyzed for R-value and density. The foam formulation and properties are listed in Table 7. Figure 2 shows the effect of FEA level on R-values. FEA-1100 provided superior R-values compared to HFC-245fa at low FEA levels, however, this improvement becomes much more pronounced as the FEA level increases. Since the level of HFC-245fa in formulations is limited by its low boiling point, FEA-1100 can significantly improve foam R-values through the use of a higher level of FEA. Ingredients (pbw) Table 7: Effect of FEA Level in Spray Foam Formulation HFC-245fa (low FEA level) FEA-1100 (low FEA level) HFC-245fa (high FEA level)* FEA-1100 (high FEA level) Mannich polyol Polyester polyol Surfactant Flame retardant and additives Catalysts FEA (moles) Water (moles) Total moles (FEA + water) Isocyanate Reaction Profile Cream time(s) Rise time(s) Tack free time(s) Foam Initial Properties Foam index Sample density (pcf) Initial R-value 75 F *Vapor pressure may exceed drum pressure rating 5

6 6 R-value Comparison (FEA-1100 vs HFC-245fa) R-value Low FEA level High FEA level (b.p >25C) HFC-245fa vs FEA-1100 HFC-245 FEA-1100 Figure 2. Effect of FEA-1100 Level on R-value FEA-1100 IN SUCROSE-BASED POLYETHER FOR APPLIANCE AND POUR-IN-PLACE APPLICATIONS Sucrose-based polyols are employed to produce foams for appliance and pour-in-place applications. In these tests, FEA-1100, HFC-245fa and HFC-365mfc were dropped-in to a formulation optimized for HFC-141b. Equi-molar quantities of FEAs and water (CO2) were employed for comparison. Table 8 summarizes the results. FEA-1100 provided superior insulation performance compared to the HCFC and HFCs. Table 8: FEA-1100 in Sucrose-based Polyether Formulation Ingredients (pbw) FEA-1100 HCFC-141b HFC-245fa HFC-365mfc Sucrose-based polyol Surfactant Catalysts Water (moles) FEA (moles) Isocyanate Reaction Profile Cream time(s) Rise time(s) Tack free time(s) Foam Initial Properties Foam index Foam density (pcf) Initial R-value 75 F

7 7 FEA-1100 IN AROMATIC POLYESTER FOR PIR BOARDSTOCK APPLICATIONS Aromatic polyester polyols are employed to produce polyisocyanurate (PIR) boardstocks for construction insulation. Table 9 summarizes the results of typical polyisocyanurate foams produced with FEA-1100 and HFC-245fa. Figure 3 shows the R-values of these foams measured upon aging. The foams expanded with FEA-1100 retain superior insulation performance (higher R values) compared to those expanded with HFC-245fa after 9 months of aging. Table 9: FEA-1100 in Polyester Formulation Ingredients (pbw) FEA-1100 HFC-245fa Aromatic polyester Surfactant Catalysts FEA (moles) Isocyanate Reaction Profile Cream time(s) Rise time(s) Tack free time(s) Foam Initial Properties Foam index Foam density (pcf) Initial R-value 75 F Figure 3. Aged R Value Comparisons: FEA-1100 and HFC-245fa, PIR Foam FEA-1100 IN TDA-BASED POLYETHER FOR APPLIANCE AND POUR-IN-PLACE APPLICATIONS TDA-based polyols are employed to produce polyurethane foams for appliance and pour-in-place applications. FEA-1100, HFC-245fa, HFC-365mfc, cyclopentane and isopentane were evaluated in a generic polyurethane formulation. Equi-molar quantities of FEA and water were added to the foam formulation listed in Table 10. Foams using these FEAs all showed uniform cell size and good dimensional stability. Table 11 summarizes the results of these polyurethane foams. FEA-1100 shows superior insulation performance compared to all other zero-odp FEAs. 7

8 8 Table 10: Foam Formulation for FEA Comparison Ingredients pbw TDA-based polyol 100 Surfactant 2.13 Catalysts 2.00 FEAs or FEA-1100 mixture (moles) 0.18 Water (moles) 0.06 Isocyanate 132 Foam index 1.2 Table 11: Foam Formulation for FEA Comparison FEAs R-value 75 F Density (pcf) FEA HFC-245fa HFC-365mfc Cyclopentane Isopentane FEA-1100 AZEOTROPIC MIXTURES The use of mixtures of physical foam expansion agents is well known, and such mixtures can be useful in optimizing foam performance and improving FEA properties. FEA-1100 forms azeotropic or azeotrope-like mixtures with HFC-245fa, HFC-365mfc, cyclopentane and isopentane. To evaluate the effect of FEA-1100 in FEA mixtures, equi-molar quantities of mixtures of FEA-1100 with HFC-245fa, HFC- 365mfc, cyclopentane and isopentane were added to the foam formulation listed in Table 11. Foams using FEA-1100 mixtures all exhibited uniform cell size good and dimensional stability. Table 12 summarizes the results and benefits of these FEA-1100 mixtures. Figure 4 shows the effect on R-value after adding FEA-1100 to other FEAs. FEAs HFC-245fa FEA-1100-HFC-245fa mixture HFC365mfc FEA-100-HFC365mfc mixture Cyclopentane FEA-1100-cyclopentane mixture Isopentane FEA-1100-isopentane mixture Table 12: FEA-1100 Azeotropic and Azeotrope-like Mixtures R-value 75 F Density (pcf) Benefits Improved GWP, b.p & R-value Improved GWP, R-value & flammability Improved R-value & flammability Improved R-value & flammability 8

9 9 Effect of FEA-1100 in Other FEAs R-value HFC-245fa & its FEA mixture HFC-365mfc & its FEA-1100 mixture Cyclopentane & its FEA-1100 mixture Isopentane & its FEA-1100 mixture Other FEAs FEA-1100-other FEA mixtures Figure 4. Effect of FEA-1100 Mixtures with HFC-245fa, HFC-365mfc, Cyclopentane and Isopentane CONCLUSIONS FEA-1100 is characterized by good environmental properties and can be employed in a broad range of foam applications to provide superior insulation performance compared to other current foam expansion agents. FEA-1100 based mixtures have also been shown to provide an improvement in foam insulation properties. Performance and materials compatibility test results indicate that FEA-1100 may be employed as a drop-in replacement for other liquid FEAs, providing superior insulation performance with low conversion costs. BIOGRAPHIES Gary Loh Gary Loh received his M.S. degree in Chemical Engineering from Georgia Institute of Technology and his MBA degree from James Madison University. He worked in variety of areas including manufacturing, R&D, and marketing, with extensive professional experience in variety of fluorocompound products. Currently, he is a Technical Service Consultant for DuPont Formacel Foam Expansion Agents Group, where he is responsible for new product development and technical service programs. Joseph (Joe) A. Creazzo Joe Creazzo is a Technical Service Engineer with DuPont at its Fluorochemicals Laboratory in Wilmington, Delaware. Joe joined DuPont in 1973 after receiving his engineering degree from Stevens Institute of Technology in New Jersey. He has held a variety of technical and manufacturing assignments in a number of areas, including Manufacturing, R&D, and Marketing. In his tenure at the Fluorochemicals Lab, Joe has work on alternatives for CFCs since Over the years in Fluorochemicals, Joe has assisted customers in several market segments where CFCs and HCFCs were phased out. Currently, he is primarily responsible for customer support and product development for DuPont s Formacel Foam Expansion Agents and Dymel Consumer, Industrial, and Pharmaceutical Propellants. Mark L. Robin Mark L. Robin, Ph.D., is Senior Technical Services Consultant for DuPont Fluoroproducts, and has 25 years of experience in the area of fluorine chemistry, including the development of CFC and HCFC replacements for fire suppression, foam blowing, and refrigeration applications. Mark is the recipient of the 2005 U.S. EPA Stratospheric Ozone Protection Award, presented for his efforts in the development of replacements for ozone depleting substances. 9

10 Copyright 2009 DuPont or its affiliates. All rights reserved. The DuPont Oval Logo, DuPont, The miracles of science, Formacel, and all products or words denoted with or are are trademarks or registered trademarks of E.I. du Pont de Nemours and Company or its affiliates. NO PART OF THIS MATERIAL MAY BE REPRODUCED, STORED IN A RETRIEVAL SYSTEM OR TRANSMITTED IN ANY FORM OR BY ANY MEANS ELECTRONIC, MECHANICAL, PHOTOCOPYING, RECORDING OR OTHERWISE WITHOUT THE PRIOR WRITTEN PERMISSION OF DUPONT. K (11/09) 10