Patent ID: 8106106

Claim:
A method for producing polyisocyanurate insulation foams, the method comprising: (i.) providing a blowing agent including isopentane and n-pentane in the substantial absence of cyclopentane, where the isopentane to n-pentane weight ratio of from 1.5:1 to 1:1; (ii.) providing a polyol stream; (iii.) combining the polyol stream and the blowing agent to form a B-side stream, where the B-side stream includes about 10 to about 40 parts by weight blowing agent per 100 parts by weight polyol, and where said step of combining takes place under a pressure in excess of 80 psi and at a temperature in excess of about 10° C.; (iv.) after said step of combining, increasing the pressure of the B-side stream to a pressure of about 1800 to about 2400 psi; (v.) providing an A-side stream including an isocyanate; (vi.) increasing the pressure of the A-side stream to a pressure of about 1800 to about 2400 psi; and (vii.) mixing the A-side stream with the B-side stream within a mix head.