Foam insulation unit

Abstract

Insulating units are disclosed which are prepared by a cavity-filling, fast-gelling rigid polyurethane foam based on a formulation comprising a polyol component which contains at least 5 weight percent of an amine-initiated polyols and 1.4 to 4 parts by weight of a catalyst package whereby the catalyst package contains at least one amine catalyst and the weight percent nitrogen present in the amine-initiated polyol to weight percent nitrogen present in the catalyst system is from 2 to 8. The formulation is injected into the cavity and the pressure in the cavity is subjected to reduced atmospheric pressure to achieve the rigid foam having a thermal conductivity of less than about 19 mW/mK at 10° C. average plate temperature.

1 . 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;
 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: 
 an organic polyisocyanate; 
 a polyol formulation comprising a polyol component containing from 5 to 85 weight percent of at least one amine-initiated polyol an nominal average functionality of 3 to 8 and an average hydroxyl number of from 200 to 850, 
 from 1 to 5 parts by weight of a catalyst system per 100 parts by weight of the polyol formulation wherein the catalyst system comprises at least one amine catalyst, 
 a non-chlorofluorocarbon physical blowing agent; and 
 an amount of water that is less than 2 percent by weight based on the polyol formulation, 
 wherein the weight percent of nitrogen in the polyol formulation, excluding the weight of the blowing agent, derived from the polyol component (Npol), is from 1 to 5 and the ratio of the weight percent nitrogen from the polyol to weight percent of nitrogen from the catalyst system (Ncat) in the polyol formulation is from 2 to 8 and the reaction mixture forms a gel in no more than 30 seconds. 
 
     
     
         2 . The insulating unit of  claim 1  wherein the foam has a thermal conductivity of less than 19 W/mK at 10° C. average plate temperature, according to ISO 12939/DIN 52612. 
     
     
         3 . The insulating unit of  claim 3  wherein the foam has a density of a density of 28 kg/ m 3  to 40 kg/m 3 . 
     
     
         4 . The insulating unit of  claim 1  wherein the amine-initiated polyol is prepared by addition of an alkylene oxide to an aromatic amine; a cyclo-aliphatic amine; methylene bis(cyclohexylamine; 1,2-, 1,3- or 1,4-bis(aminomethyl)cyclohexane; an aminocyclohexanealkylamine; 2- or 4-alkylcyclohexane-1,3-diamine; isophorone diamine or a combination thereof. 
     
     
         5 . The insulating unit of  claim 4  wherein the amine-initiated polyol comprises from 18 to 60 weight percent of the polyol component. 
     
     
         6 . The insulating unit of  claim 5  wherein the Ncat comprises 0.3 to 0.7 weight percent based on the polyol formulation, excluding the weight of the blowing agent. 
     
     
         7 . The insulating unit of  claim 6  wherein the ratio of Npol to Ncat is from 2.2 to 6. 
     
     
         8 . The insulating unit of  claim 1  wherein the polyisocyanate is selected from the group consisting of 4,4′-, 2,4′- and 2,2′-diphenylmethane diisocyanate and the corresponding isomer mixtures; mixtures of 4,4′- and 2,4′-diphenylmethane diisocyanates; polyphenyl-polymethylene polyisocyanates; mixtures of 4,4′, 2,4′- and 2,2′-diphenylmethane diisocyanates; and combinations thereof. 
     
     
         9 . The insulating unit of  claim 8  wherein the polyol formulation has a viscosity of at least 5,000 cP at 25° C. measured according to ASTM D445. 
     
     
         10 . 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;
 a polyol formulation comprising a polyol component containing from 5 to 85 weight percent of at least one amine-initiated polyol, an nominal average functionality of 3 to 8 and an average hydroxyl number of from 200 to 850, 
 from 1 to 5 parts by weight of a catalyst system per 100 parts by weight of the polyol component wherein the catalyst system comprises at least one amine catalyst, 
 a non-chlorofluorocarbon physical blowing agent; and 
 an amount of water that is less than 2 percent by weight based on the polyol formuation, wherein the weight percent of nitrogen in the formulation, excluding the weight of the blowing agent, derived from the polyol component (Npol) is from is from 1.4 to 5 and the ratio of Npol to the weight percent nitrogen from the catalyst system (Ncat) is from 2 to 8; 
 
 (b) injecting the reactive foam-forming system at or above atmospheric pressure into a cavity, wherein the reactive foam-forming system forms a gel in no more than 30 seconds 
 (c) subjecting the cavity to a reduced atmospheric pressure; and 
 (d) maintaining the reduced atmospheric pressure at least until the gel forms a closed cell rigid polyurethane foam, the foam having a density of from 28 to 40 kg/m 3 , an average cell diameter of less than about 250 microns, a thermal conductivity of less than about 19 mW/mK at 10° C. average plate temperature, according to ISO 12939/DIN. 52612. 
 
     
     
         11 . The process of  claim 10  wherein the amine-initiated polyol is prepared by addition of an alkylene oxide to an aromatic amine; a cyclo-aliphatic amine; methylene bis(cyclohexylamine; 1,2-, 1,3- or 1,4-bis(aminomethyl)cyclohexane; an aminocyclohexanealkylamine; 2- or 4-alkylcyclohexane-1,3-diamine; isophorone diamine or a combination thereof. 
     
     
         12 . The process of  claim 11  wherein the amine-initiated polyol comprises from 18 to 60 weight percent of the polyol component. 
     
     
         13 . The process of  claim 12  wherein the nitrogen present in the polyol formulation, excluding the weight of the blowing agent, comprises from 1.4 to 5 weight percent of the formulation. 
     
     
         14 . The process of  claim 12  wherein Ncat comprises 0.3 to 0.7 weight percent based on the formulation, excluding the weight of the blowing agent. 
     
     
         15 . The process of  claim 14  wherein the ratio of Npol to Ncat is from 2.2 to 6. 
     
     
         16 . The process of  claim 15  catalyst system comprises a blowing and curing catalyst is selected from dimethylbenzylamine, N-methyl-, N-ethyl-, and N-cyclohexylmorpholine, N,N,N′,N′-tetramethylbutanediamine and -hexanediamine, bis(dimethylamino-propyl)urea, dimethylpiperazine, dimethylcyclohexylamine, 1,2-dimethyl-imidazole, 1-aza-bicyclo[3.3.0]octane, triethylenediamine, or a combinations thereof.