Catalysts for Improved Spray Foam System Stability and Reactivity with Low GWP Blowing Agents

摘要

Polyurethane spray foam has emerged as an insulation material of choice for improving energy efficiency in the construction market. The high R-values achievable, coupled with fast, on-site application have helped fuel the growth of spray foam globally. However, formulations for closed-cell spray foam have traditionally contained hydrochlorofluorocarbons (HCFC's) such as HCFC-141b, or hydrofluorocarbons (HFC's) such as HFC-245fa and HFC-365 as auxiliary blowing agents. Although these blowing agents offer excellent insulating values and handling properties, there have been increasing concerns in the public with respect to the high ozone depleting potential (ODP) of HCFC's and high global warming potential (GWP) of HFC's. These concerns are addressed under the Montreal and Kyoto Protocols, respectively, and call for the eventual replacement of these blowing agents with new options that have both low ODP and low GWP. Air Products and Chemicals, Inc. has previously developed catalysts for spray foam with improved stability, reduced emissions, or reduced odor compared to the prior generation of catalysts. The current paper will describe our latest catalyst developments designed to provide both excellent system stability and reactivity for closed-cell spray foam systems incorporating low GWP blowing agents such as HFCO-1233zd(E).