Novel Natural Oil Polyols and their use in Rigid Polyurethane Insulating Foams

摘要

Over the past decade there has been growing interest in Natural Oil Polyols (NOPs) and their use as raw materials inthe manufacture of polyurethanes. The use of NOPs, which are based at least in part on renewable raw materials, isexpected to increase because these polyols are seen as being more desirable than petroleum-based materials.However, the NOPs that have been available until now have some drawbacks that limit their usefulness. Most of thecommercially available NOPs have relatively low hydroxyl functionalities and relatively high equivalent weights,which make them most suited for use in solid polyurethanes and flexible foams. Since most of these polyols arelargely based on fatty acid triglycerides, the NOPs may have very different solubility characteristics than conventionalpolyether and polyester polyols. The fatty acid portion of these NOPs may increase their solubility with hydrocarbonblowing agents such as cyclopentane, isopentane, and n-pentane, but at the same time may limit their compatibilitywith conventional polyols. Other commercially available NOPs may have good solubility with conventional polyols,but not with hydrocarbon blowing agents.Recently Bayer MaterialScience (BMS) has developed a process for making NOPs that overcomes many of theseobstacles and allows the preparation of polyols that are suitable for use in rigid polyurethane insulating foams. Someof the key characteristics of these polyols are a high biobased content and excellent compatibility with bothhydrocarbon blowing agents and conventional polyols. Furthermore, these NOPs can be prepared with a wide rangeof physical properties. Natural oil-based polyols with hydroxyl functionalities ranging from 2 to 5 and equivalentweights ranging from about 140 to 280 have been prepared.We have demonstrated the usefulness of these polyols in making rigid polyurethane foams with a variety of blowingagents including cyclopentane, hydrofluorocarbons and water with properties generally comparable to those ofconventional polyurethane foams. In addition, we have been able to prepare polyurethane foams blown withisopentane and normal pentane that are often not feasible with conventional polyols because of the low solubility ofthese blowing agents.