Patent ID: 6617368
Filing Date: 2003-09-09
Classification: C08G

Abstract:
A process for the preparation of a rigid foam comprising the step of reacting:(A) an organic polyisocyanate component selected from the group consisting of: (1) a polymethylene poly(phenylisocyanate) having an NCO group content of 30.5% to 33.0%, and a monomer content of 42 to 48%, wherein: (i) less than about 0.5% comprises the 2,2â€²-isomer, (ii) from about 2 to about 4% comprises the 2,4â€²-isomer, (iii) from about 40 to about 46% comprises the 4,4â€²-isomer, and (iv) from about 52 to about 58% by weight comprises higher ring homologues of the MDI series; with the %'s by weight of (A)(1)(i), (A)(1)(ii), (A)(1)(iii) and (A)(1)(iv) totaling 100% by weight of the component (A)(1); and (2) an NCO-terminated prepolymer having an NCO group content of about 26.0% to about 30.0%, and comprising the reaction product of: (a) a polyester comprising the reaction product of (i) pure ortho-phthalic acid or phthalic anhydride; and (ii) a glycol; and (b) a polymethylene poly(phenylisocyanate) having an NCO group content of about 30.5% to 33.0% and a monomer content of about 42 to about 48%, wherein: (i) less than about 0.5% by weight comprises the 2,2â€²-isomer, (ii) from about 2 to about 4% by weight of the 2,4â€²-isomer, (iii) from about 40 to 46% by weight of the 4,4â€²-isomer; and (iv) from about 52 to about 58% by weight of higher ring homologues of the diphenylmethane diisocyanate series, with the %'s by weight of (A)(2)(b)(i), (A)(2)(b)(ii), (A)(2)(b)(iii) and (A)(2)(b)(iv) totaling 100% by weight of (A)(2)(b) the polyisocyanate component; with (B) an isocyanate-reactive component comprising: (1) from 2 to 20% by weight, based on 100% by weight of (B), of a liquid OH-terminated prepolymer having a viscosity of at least about 100,000 mPaÂ·s at 25Â° C., and which comprises the reaction product of: (a) an organic aromatic polyisocyanate component; and (b) an amine initiated polyether polyol component; (2) from 50 to 98% by weight, based on 100% by weight of component (B), of at least one polyether polyol having a molecular weight of from 280 to 1,120, a functionality of from 2 to 6, and an OH number of from 300 to 800; and (3) from 0 to 30% by weight, based on 100% by weight of (B), of at least one aromatic polyester polyol having an OH number of from 100 to 400, and a functionality of 1.8 to 2.5; in the presence of:(C) at least one catalyst; and (D) at least one blowing agent; wherein the relative amounts of components present is such that the Isocyanate Index is from 90 to 170.