Effective Use of Compatibilizers to Achieve Resin Stability with Hydrocarbon Blowing Agents

The increasing use of hydrocarbon blowing agents brings with it additional problems for resin producers. First and foremost are the flammable hazard and VOC restrictions. However, resin incompatibility is another issue that is not as obvious. It is difficult to obtain a homogeneous resin mixture because dissimilar polarities of typical polyols and hydrocarbons lead to separation when not stirred sufficiently and/or continuously. This can result in separation of resin components in storage vessels. The purpose of this presentation is to offer a formulation technique that avoids resin separation. Resin stability can be achieved through the addition of additives described as compatibilizers. Suitable compatibilizers will be identified chemically and by trade name. Also, the optimum compatibilizer will be matched to the type of polyol used in the resin. The amount of compatibilizer added to the resin determines whether the resin is a stable emulsion or a micro-emulsion. Data will be presented identifying additive levels required to obtain both states, as well as the storage stability of typical resins. Physical property data will also be presented to demonstrate the effect the compatibilizer has on rigid foam properties.