| abstract |
A method of producing a polyurethane or polyisocyanurate foam which involves the use of a specific combination of hydrofluoroolefin blowing agents and cell nucleators. The blowing agents used are water and a halogenated olefin selected from 1-chloro-3,3,3-trifluoropropene; 1-chloro-2,3,3,3-tetrafluoropropene; 1,3,3,3-tetrafluoropropene; 2,3,3,3-tetrafluoropropene and 1,1,1,4,4,4-hexafluoro-2-butene. The nucleating agent is defined by Formula 1 below: Where R1 is chosen from F, CF3, CF2CF3 and CF2CF3; R2 is chosen from F, CF3, CF2CF3 and CF2CF3; R3 is chosen from F, CF3, CF2CF3, CF2CF3 and CF(CF3)2 and R4 is chosen from F, CF3, CF2CF3, CF2CF3 and CF(CF3)2. Polyols and polyisocyanates are used as the reactive components. A surfactant, preferably a polyether-polysiloxane copolymer is used, along with catalysts, especially tertiary aliphatic amines and organotin compounds. The rigid polyurethane and polyisocyanurate boards may be used to insulate refrigeration bodies, such as those employed in vehicles comprising refrigeration units, and cold storage containers. |