Publication: Study on new FR silicone stabilizer for liquid CO2 technology
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Rapra Technology Ltd.
Since the implementation of the Montreal Protocol and the Clean Air Act Amendment of 1990, the polyurethane industry has been searching for ways to reduce or eliminate auxiliary blowing agents (ABAs) from foam manufacturing processes. Many possible solutions have been explored, both mechanical and chemical, with no simple cost-effective solution for total elimination. Alternative blowing agents have been explored for many years, which include: HCFCs, acetone and most recently carbon dioxide. Although these materials are reasonable options, carbon dioxide has shown the most promise because it is safe (i.e. non-flammable) to use and also inexpensive. Also CO2 is a non-hazardous chemical which can be incorporated in the system and used to blow the foam down to low densities. Today there are three machine manufacturers with commercial equipment to produce flexible foam using auxiliary CO2 as a blowing agent: Cannon CarDio(R), Hennecke NovaFlex(R) and Beamech CO-2(TM) machines. With the introduction of these machines it is clear that this is a viable, inexpensive method to reduce and/or eliminate regulated blowing agents. Since these are new manufacturing processes, chemical manufacturers are diligently working with the technologies to identify the best raw materials for trouble-free processing and optimum foam quality. The mechanical and chemical differences between conventional and the CO2-based foaming processes indicate that the role of the silicone stabilizer is process dependent. Laboratory froth and foam experiments have been conducted to evaluate and predict which silicone stabilizers are the most viable for this new foaming process.