A Fundamental Study on Aromatic Polyether Polyols for Rigid Polyurethane Foams

摘要

Polyols with high aromaticity and functionality,Resonance~TM aromatic polyether polyols (APEP) were evaluated in model rigid polyurethane foam formulations.These aromatic polyols replaced the conventional sugar-based polyether polyol in one study (Evaluation 1) and sugar-based polyether polyol along with aromatic polyester polyol (APP) in another study (Evaluation 2).The intent of the studies was to use model and commercial products to demonstrate the effectiveness of higher levels of aromaticity primarily on reaction to fire.Evaluation 1 is a simplified PUR rigid foam formulation wherein a sugar-based polyether polyol (PEP) was replaced by Hexion's Resonance~TM APEP-the PM and TM series,at 50 to 75% levels.The effects of replacing the PEP with Resonance~TM polyols on the physical properties such as compression strength,dimensional stability and reaction to fire were assessed.Evaluation 2 is based on a model spray foam formulation wherein the reference contained a mixture of APP,PEP and Mannich polyols.Herein,Resonance~TM APEPs (PL91-203 and PL91-205) replaced 100% of PEP in one experiment and all of PEP and ca.33% APP in the other experiment while the level of Mannich polyols was kept constant in both experiments.Replacement of sugar-based polyol with Hexion's PM,RL and TM polyols resulted in significant improvement in compression strength and reaction to fire along with finer cell structure,which are expected to provide better insulation properties.Replacement of PEP and APP with Hexion's PL materials resulted in remarkable improvement in reaction to fire where 50% of some of the foams tested with Resonance~TM APEP did not propagate fully through the sample maintaining other properties such as dimensional stability.