RIGID POLYURETHANE FOAM THAT HAS A SMALL SIZE Russian patent published in 2018 - IPC C08J9/12 C08G18/66 B29C44/10 

FIELD: technological processes.

SUBSTANCE: invention offers a rigid polyurethane foam (PFA) having small cells. Rigid PFA is manufactured in a manner that includes the use of carbon dioxide, exerting pressure at the level of the first target value for a mixture of a polyhydric alcohol comprising a polyhydric alcohol, a catalyst and a surfactant. Pressure is maintained at the level of the first set value for the first set time to increase the concentration of carbon dioxide in a mixture of polyhydric alcohol. Isocyanate is mixed with a mixture of a polyhydric alcohol to form a polyurethane reaction mixture. Pressure produced on the polyurethane reaction mixture is optionally maintained at the level of the first predetermined value for a second predetermined time. Pressure produced on the polyurethane reaction mixture is then increased to a second predetermined value that is greater than the first value. Polyurethane reaction mixture is then discharged at a predetermined rate of pressure reduction from the pressure after the expiration of the third predetermined time and a rigid PFA is obtained, the third predetermined time being less than 30 minutes.

EFFECT: resulting polyurethane foam has a number-average cell size of not more than 10 mcm.

10 cl, 6 tbl, 10 ex