RIGID POLYURETHANE FOAM HAVING A SMALL CELL SIZE

摘要

A rigid polyurethane (PU) foam having a number average cell size of no greater than 10

主权项

1. A method for preparing a rigid polyurethane foam, comprising:
using carbon dioxide to provide a pressure at a first predetermined value on a polyol mixture that includes a polyol, a catalyst and a surfactant; maintaining the pressure at the first predetermined value for a first predetermined time; mixing an isocyanate with the polyol mixture to form a polyurethane reaction mixture; optionally maintaining the pressure on the polyurethane reaction mixture at the first predetermined value for a second predetermined time; increasing the pressure on the polyurethane reaction mixture from the first predetermined value to a second predetermined value greater than the first predetermined value; and releasing the polyurethane reaction mixture at a predetermined depressurization rate from the pressure after a third predetermined time to prepare the rigid polyurethane foam, where the third predetermined time is less than 30 minutes.