Patent ID: 9580539
Date: 2017-02-28
CPC Classifications: B29C,B29K,B29L,C08G,C08J,Y10T

Claim:
1. A process for preparing an insulating unit comprising at least two side walls, a back wall and a top wall wherein each wall comprises a polyurethane foam between an inner lining and an outer lining and the side walls are connected to the back wall and the top wall at an angle between 85 and 95°; the back wall and the side walls have a height of between 0.5 and 3 meters and the side walls have a width of between 0.5 and 1.5 meters and the back wall has a width of between 0.5 and 2.0 meters and wherein the polyurethane foam disposed between the inner and outer liner has a thickness of 20 to 120 mm and is produced from a reaction mixture comprising; (a) preparing a reactive foam-forming system comprising as components at least an organic polyisocyanate; and a polyol formulation comprising a 1) polyol component that includes a mixture of polyols, the polyol component containing from 5 to 85 percent by weight of the polyol component of at least one amine-initiated polyol, said at least one amine-initiated polyol having a nominal average functionality of 3 to 8 and an average hydroxyl number of from 200 to 850, 2) from 1 to 5 parts by weight of the polyol formulation of a catalyst system per 100 parts by weight of the polyol component wherein the catalyst system comprises at least one amine catalyst, 3) an amount of water that is less than 2 percent by weight based on the weight of the polyol formulation, 4) at least one surfactant, and 5) a non-chlorofluorocarbon physical blowing agent; wherein the weight percent of nitrogen derived from the at least one amine-initiated polyol having a nominal average functionality of 3 to 8 and an average hydroxyl number of from 200 to 850 (Npol), based on the combined weight of components 1), 2), 3) and 4) of the polyol formulation, is from is from 1.4 to 5 and the ratio of Npol to the weight percent nitrogen from the catalyst system (Ncat), based on the combined weight of components 1), 2), 3) and 4) of the polyol formulation, is from 2 to 8; (b) injecting the reactive foam-forming system into a cavity; (c) before, curing or after step (b) subjecting the cavity to a reduced atmospheric pressure of 350 to 850 millibars; and (d) wherein the reactive foam-forming system forms a gel in no more than 30 seconds and the reduced atmospheric pressure is maintained at least until the gel forms a closed cell rigid polyurethane foam, the foam having a density of from 28 to 40 kg/m