CASE Application of PPG with High Primary Hydroxyl Content

Abstract

PPG is able to produce urethane resin by reacting with isocyanate, and it is widely used in urethane foam and CASE applications. PPG is obtained by ring-opening polymerization of PO or EO to an active hydrogen compound. When PO is used, most of the terminal hydroxyl groups of the resulting PPG are secondary. Secondary hydroxyl group has low reactivity with Isocyanate, but such PPG is highly hydrophobic. When EO is used, the terminal hydroxyl groups are mainly primary. It has high reactivity, but the water resistance of the urethane resin is low because of its high hydrophilicity. By using a special acid catalyst, we have succeeded in obtaining a PPG having a higher primary ratio of the terminal hydroxyl groups even with PO. Such primary OH-PPG provides high water resistance and high reactivity; which are known as the conflicting performance. As an example of use in the CASE application of Primary OH-PPG is to shorten the construction period and prevent resin blistering of the waterproof coating in construction. In adhesive applications, it is possible to obtain a low-viscosity and fast-setting potting material and an adhesive excellent in low-temperature characteristics and static shear adhesion.