Patent ID: 7838568

Claim:
A method of manufacturing a polyisocyanurate foam insulation board, the method comprising: contacting a stream of reactants that comprise an isocyanate-reactive compound with a stream of reactants that include an isocyanate compound in a mix head at a pressure of about 1800 psi to 2400 psi to form a reaction product, where said step of contacting takes place in said mix head in the presence of a blowing agent and air, where the blowing agent is selected form the group consisting of alkanes, (cyclo)alkanes, hydrofluorocarbons, hydrochlorofluorocarbons, fluorocarbons, fluorinated ethers, alkenes, alkynes and noble gases; and adding an effective amount of the air in the stream of reactants comprising the isocyanate-reactive compound, or the stream of reactants including the isocyanate compound, or both, to increase the volume of developing foam as it instantaneously leaves the mix head prior to the time any blowing agent that relies on a heat of reaction to expand can contribute to any foaming process under atmospheric pressure by at least 1.25.