The issues of ozone depletion and climate change have been at the vanguard of the global environmental agenda for several years. There is a general acceptance that man-made chemicals and human activities exert a significant adverse impact on the global climate. The Ozone layer absorbs most of the harmful ultraviolet-B radiation from the sun and filters out lethal UV-C radiation. The ozone layer over the Antarctic has steadily weakened since measurements started in the 1980s, and in 2003, the size of the ozone hole peaked at around 28 mln sq km. Man made chemicals which are responsible for most of the chlorine and bromine causing ozone depletion are methyl bromide, methyl chloroform, carbon tetrachloride as well as families of halons, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The Montreal Protocol has resulted in phasing out of over 96% of all ozone-depleting substances (ODSs). This quantitative success in the protection of the ozone layer has also achieved important climate benefits because many ozone depleting substances controlled under the Protocol are also potent greenhouse gases.
Polyurethane is an important commodity polymer with global consumption in 2008 exceeding 6.5-7 mln tons, and has major usage in the foam of foams. Flexible polyurethane foams are also used extensively for cushioning in furniture and some types of packaging, and to manufacture a wide range of components for the automotive industry. Most rigid polyurethane foam applications make use of its insulation properties, its high strength-to-weight ratio and its low density. One of the reasons for its effective insulating properties is the blowing agents used to create the fine cellular structure of the foam, often highly insulating gaseous materials that are trapped within each of the small cells of the foam. Hence, foamed products require blowing agent for foaming process. Chemical blowing was earlier done with CFC (Fluorocarbon) that has been phased out in most developed economies because of greater depletion of ozone in the atmosphere. HCFC (Hydro fluorocarbon) was being used as an alternate. HCFC-141b, HCFC-142b and HCFC-22 found use in the manufacture of several types of polyurethane foams and extruded polystyrene and polyethylene foams. Though foam blowing is one on the main uses of HCFCs globally, use of HCFC causes ozone-depletion. In September 2007, the 20th anniversary of the Montreal Protocol, Parties to the Montreal Protocol agreed to accelerate the phase-out of HCFCs, bringing the final phase-out date forward by 10 years for Article 5 countries. They also agreed to provide sufficient and stable funding to developing countries to achieve the accelerated phase out. In response to on-going environmental concerns, non-Article 5(1) countries continue to reduce the consumption of HCFCs to comply with the Montreal Protocol control schedule. National and regional bans on specific HCFC applications and the accelerated European HCFC phase-out are drastically reducing global HCFC demand. The HCFC phasing out program basically comprises:
Base level will be determined by the usage of HCFC by 2009 & 2010
Freeze at 2013 level in future
10% reduction by 2015
35 % reduction by 2020
67.5 % reduction by 2025
100% reduction or complete elimination of HCFC by 2030
All HCFC blowing agents have been totally phased out in Europe. European PU industry has adopted hydrocarbon - pentane which offers a permanent replacement solution to HCFC. Usage of pentane entails a large investment in an explosion proof factory to safeguard against the high volatility of this material. Therefore this alternative could prove very difficult for small foam processors. However, the variable cost is reduced due to lower cost of pentane. The other alternatives are HFC such as 245fa & HFC 365mfc. Both of these have also lower boiling points and cost more than pentane. Carbon dioxide, if used with these HFC blowing agent can reduce the dosage of expensive HFC blowing agents. Methyl Formate is an environmentally alternative blowing agent that is a non-ozone depleting additive with no Global Warming Potential (GWP). HCFC 141b has been phased out in USA. These have been mostly replaced by less ozone depleting substances known as HCFC's, including HCFC-141b and HCFC-22, also known as "second generation" blowing agents. HFC-134a is a third generation" blowing agent which is completely non-ozone depleting and non-flammable. The ideal foam expansion agents should exhibit the following characteristics:
Low vapor thermal conductivity
Nonflammaility
Liquid at room temperature (Boiling point greater than 25 Deg C)
Low toxicity
Zero ODP
Low GWP
Chemical, thermal stability
Soluble in formulation
Low rate of diffusion
Economically feasibility
The need for insulation materials with improved energy efficiency and environmental profiles has led Arkema to investigate a range of low-GWP blowing agents designed for most PUR applications. These fourth-generation blowing agents; the AFA series, are being developed in both liquid and gas formulations to replace HFCs such as 245fa and 134a. AFA-G1, and to a lesser extent AFA-G2, have shown to potentially compete with HFC-134a in terms of solubility in polyol, dimensional stability, and K-factor, although AFA-G1 seems to perform less well at very cold temperatures. AFA-L1 displayed a similar blowing efficiency and dimensional stability and a significant advantage on k-factor compared to hydrocarbons.
DuPont Fluoroproducts has developed a novel Fourth-Generation foam expansion agent for polyurethane foams- FEA-1100 that is characterized by zero ozone depletion potential, very low acute toxicity, and with a low GWP value of 5. Because it is liquid at room temperature, the problems associated with the use of lower boiling agents such as HFC-245fa are eliminated. In addition, FEA-1100 has been shown to be non-flammable in standard ASTM tests. Polyurethane foams produced with these are characterized by low foam density, uniform cell size, and R values higher than HFC-245fa.
The industry is continuing its search for better options compared for environmental safety at a lower capital cost. Manufacturers are developing environmentally safer blowing agents to replace for PU foam industry. New generation blowing agents are being developed but are not yet commercialized. This will lead to reduction in global demand for HCFCs, almost certainly leading to a decrease in global supply through the closure of some existing facilities.
Polyurethane is an important commodity polymer with global consumption in 2008 exceeding 6.5-7 mln tons, and has major usage in the foam of foams. Flexible polyurethane foams are also used extensively for cushioning in furniture and some types of packaging, and to manufacture a wide range of components for the automotive industry. Most rigid polyurethane foam applications make use of its insulation properties, its high strength-to-weight ratio and its low density. One of the reasons for its effective insulating properties is the blowing agents used to create the fine cellular structure of the foam, often highly insulating gaseous materials that are trapped within each of the small cells of the foam. Hence, foamed products require blowing agent for foaming process. Chemical blowing was earlier done with CFC (Fluorocarbon) that has been phased out in most developed economies because of greater depletion of ozone in the atmosphere. HCFC (Hydro fluorocarbon) was being used as an alternate. HCFC-141b, HCFC-142b and HCFC-22 found use in the manufacture of several types of polyurethane foams and extruded polystyrene and polyethylene foams. Though foam blowing is one on the main uses of HCFCs globally, use of HCFC causes ozone-depletion. In September 2007, the 20th anniversary of the Montreal Protocol, Parties to the Montreal Protocol agreed to accelerate the phase-out of HCFCs, bringing the final phase-out date forward by 10 years for Article 5 countries. They also agreed to provide sufficient and stable funding to developing countries to achieve the accelerated phase out. In response to on-going environmental concerns, non-Article 5(1) countries continue to reduce the consumption of HCFCs to comply with the Montreal Protocol control schedule. National and regional bans on specific HCFC applications and the accelerated European HCFC phase-out are drastically reducing global HCFC demand. The HCFC phasing out program basically comprises:
Base level will be determined by the usage of HCFC by 2009 & 2010
Freeze at 2013 level in future
10% reduction by 2015
35 % reduction by 2020
67.5 % reduction by 2025
100% reduction or complete elimination of HCFC by 2030
All HCFC blowing agents have been totally phased out in Europe. European PU industry has adopted hydrocarbon - pentane which offers a permanent replacement solution to HCFC. Usage of pentane entails a large investment in an explosion proof factory to safeguard against the high volatility of this material. Therefore this alternative could prove very difficult for small foam processors. However, the variable cost is reduced due to lower cost of pentane. The other alternatives are HFC such as 245fa & HFC 365mfc. Both of these have also lower boiling points and cost more than pentane. Carbon dioxide, if used with these HFC blowing agent can reduce the dosage of expensive HFC blowing agents. Methyl Formate is an environmentally alternative blowing agent that is a non-ozone depleting additive with no Global Warming Potential (GWP). HCFC 141b has been phased out in USA. These have been mostly replaced by less ozone depleting substances known as HCFC's, including HCFC-141b and HCFC-22, also known as "second generation" blowing agents. HFC-134a is a third generation" blowing agent which is completely non-ozone depleting and non-flammable. The ideal foam expansion agents should exhibit the following characteristics:
Low vapor thermal conductivity
Nonflammaility
Liquid at room temperature (Boiling point greater than 25 Deg C)
Low toxicity
Zero ODP
Low GWP
Chemical, thermal stability
Soluble in formulation
Low rate of diffusion
Economically feasibility
The need for insulation materials with improved energy efficiency and environmental profiles has led Arkema to investigate a range of low-GWP blowing agents designed for most PUR applications. These fourth-generation blowing agents; the AFA series, are being developed in both liquid and gas formulations to replace HFCs such as 245fa and 134a. AFA-G1, and to a lesser extent AFA-G2, have shown to potentially compete with HFC-134a in terms of solubility in polyol, dimensional stability, and K-factor, although AFA-G1 seems to perform less well at very cold temperatures. AFA-L1 displayed a similar blowing efficiency and dimensional stability and a significant advantage on k-factor compared to hydrocarbons.
DuPont Fluoroproducts has developed a novel Fourth-Generation foam expansion agent for polyurethane foams- FEA-1100 that is characterized by zero ozone depletion potential, very low acute toxicity, and with a low GWP value of 5. Because it is liquid at room temperature, the problems associated with the use of lower boiling agents such as HFC-245fa are eliminated. In addition, FEA-1100 has been shown to be non-flammable in standard ASTM tests. Polyurethane foams produced with these are characterized by low foam density, uniform cell size, and R values higher than HFC-245fa.
The industry is continuing its search for better options compared for environmental safety at a lower capital cost. Manufacturers are developing environmentally safer blowing agents to replace for PU foam industry. New generation blowing agents are being developed but are not yet commercialized. This will lead to reduction in global demand for HCFCs, almost certainly leading to a decrease in global supply through the closure of some existing facilities.
