Blowing agent, process for preparing rigid polyurethane foam or polyisocyanurate foam, and foam prepared thereby

Abstract

In the present invention, a rigid polyurethane foam or polyisocyanurate foam is prepared by mixing an isocyanate with a premix of a polyol, a blowing agent, a reaction catalyst, a foam stabilizer and other additives, in which 1,1,1,3,3-pentafluoropropane is used as the blowing agent in combination with a vapor pressure depressant therefor that includes at least one compound compatible with 1,1,1,3,3-pentafluoropropane.

1 . A blowing agent for preparing a rigid polyurethane foam or polyisocyanurate foam, said blowing agent comprising 1,1,1,3,3-pentafluoropropane and a vapor pressure depressant therefor in an amount of 1 to 80 parts by weight based on 100 parts by weight of the blowing agent; said vapor pressure depressant being at least one compound compatible with 1,1,1,3,3-pentafluoropropane and selected from the group consisting of dimethyl carbonate, methyl formate, γ-butyrolacetone, tetrahydrofuran, dimethyoxymethane, 1,3-dioxolane, acetonitrile, N-methyl-2-pyrrolidone, sulfoxide, dimethyl sulfoxide and sulfolane.  
     
     
         2 . A blowing agent as claimed in  claim 1 , wherein said at least one compound has a boiling point higher than or equal to 20° C. and is capable of being completely mixed with 1,1,1,3,3-pentafluoropropane.  
     
     
         3 . A blowing agent as claimed in  claim 1 , wherein the vapor pressure depressant is contained in an amount of 1 to 50 parts by weight, based on 100 parts by weight of the blowing agent.  
     
     
         4 . A rigid polyurethane foam or polyisocyanurate foam preparation process, said process comprising: 
 providing a premix consisting of a blowing agent, at least one polyol, a reaction catalyst, a foam stabilizer, at least one additive and water; 
 said blowing agent consisting of 1,1,1,3,3-pentafluoropropane and a vapor pressure depressant therefor in an amount of 1 to 80 parts by weight based on 100 parts by weight of the blowing agent, said vapor pressure depressant being at least one compound compatible with 1,1,1,3,3-pentafluoropropane and selected from the group consisting of dimethyl carbonate, methyl formate, γ-butyrolacetone, tetrahydrofuran, dimethyoxymethane, 1,3-dioxolane, acetonitrile, N-methyl-2-pyrrolidone, sulfoxide, dimethyl sulfoxide and sulfolane;  
 said at least one additive being a flame retardant, a surfactant or a 1,1,1,3,3-pentafluoropropane stabilizing agent selected from the group consisting of α-methyl styrene and isopropenyl toluene; and  
   reacting said premix with at least one isocyanate.    
     
     
         5 . A process as claimed in  claim 4 , wherein said 1,1,1,3,3-pentafluoropropane is contained in an amount of 1 to 80 parts by weight based on 100 parts by weight of the polyol, and each of the foam stabilizer and the reaction catalyst is contained in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the polyol.  
     
     
         6 . A process as claimed in  claim 5 , wherein said 1,1,1,3,3-pentafluoropropane is contained in an amount of 10 to 60 parts by weight based on 100 parts by weight of the polyol.  
     
     
         7 . A process as claimed in  claim 4 , wherein the flame retardant is a phosphoric ester compatible with 1,1,1,3,3-pentafluoropropane.  
     
     
         8 . A process as claimed in  claim 7 , wherein the phosphoric ester is selected from the group consisting of tris(2-chloroethyl)phosphate, tris(2-chloropropyl)phosphate, tris(butoxyethyl)phosphate, trimethyl phosphate, triethyl phosphate, triphenyl phosphate and tris(isopropylphenyl)phosphate.  
     
     
         9 . A process as claimed in  claim 7 , wherein the flame retardant is contained in an amount of 10 to 30 parts by weight based on 100 parts by weight of the polyol.  
     
     
         10 . A process as claimed in  claim 4 , wherein the surfactant is selected from the group consisting of hydrocarbon surfactants and hydrofluorocarbon surfactants.  
     
     
         11 . A process as claimed in  claim 4 , wherein said at least one compound of the vapor pressure depressant has a boiling point higher than or equal to 20° C. and is capable of being completely mixed with 1,1,1,3,3-pentafluoropropane.  
     
     
         12 . A process as claimed in  claim 4 , wherein the vapor pressure depressant is contained in an amount of 1 to 50 parts by weight based on 100 parts by weight of the blowing agent.  
     
     
         13 . A rigid polyurethane foam or polyisocyanurate foam prepared by the process as set forth in  claim 4.