ABSTRACT
This paper describes the fundamental investigation of amine catalysts for appliance blown with the next generation blowing agents.
HCFC-141b has been widely used as a blowing agent in rigid polyurethane foams, still it will be phased out by 2002 in the United States and Europe and by 2003 in Japan due to its higher ozone depletion potential (ODP).
Although HFC-245fa and HFC-365mfc (HFCs) have been proposed as candidates of the next generation blowing agents, their lower solubility in polyols and differences in physical properties compared with HCFC-141b cause serious problems in production of rigid foams, like:
Higher thermal conductivity of the foam. Due to the high price of HFCs, a higher dosage level of water as co-blowing agent is used to reduce the cost.
Lower adhesion on substrates at low temperature.
Inferior flowability resulting in a higher density foam.
Inferior dimensional stability at low temperature. 365- mfc is easy to be liquefied at low temperature due to its high boiling point (40°C).
HFCs are difficult to handle because of the low boiling point (15°C) of 245fa and flammability of 365mfc.
In order to solve these problems, various investigations have been reported from the view of blowing agents and main raw materials such as polyol. However there are only a few reports related to the development of catalysts.
TOSOH Corporation has carried out detailed examinations associated with various catalysts in HFC blown rigid foams and has successfully developed novel amine catalyst systems for the next generation blowing agents. In contrast to the conventional amine catalysts, the new TOSOH catalyst systems result in foam properties identical to HCFC-141b blown foams. It is possible to produce a low density foam with good properties such as, higher flowability, lower k-factor better dimensional stability at low temperature and.
In this paper, HFCs blown systems are discussed from a standpoint of amine catalysts and TOSOH’s new catalyst systems are introduced for the next generation blowing agents.
