Physical blowing agents for polyurethanes

Abstract

Polyurethane foam materials are the majority among all foam materials. Additionally, they are main part of all produced polyurethanes. Therefore, the problem of selection of suitable blowing agents is very crucial from the point of view of technological, economic and environmental protection benefits. The work is collected and discussed all kinds of physical blowing agents which are used in the production of polyurethane foams. The basic blowing agents used in the polyurethane technology include: chlorofluorocarbons (CFCs), hydrogenated fluorocarbons (HFCs), hydrogenated chlorofluorocarbons (HCFCs), low-boiling saturated and unsaturated hydrocarbons, hydrofluoroethers (HFEs) and carbon dioxide. Issues related to the problem of selecting a suitable foaming agent, taking into account the environmental impacts, foam production costs and the impact on their properties, especially on the heat-insulation, combustibility, have been widely discussed in the work.