Process for producing a low density free-rise polyurethane foam

Abstract

There is described a process for producing a free-rise polyurethane foam having a density of less than or equal to about 0.75 pcf. the the process comprises the steps of: (a) contacting: (i) an isocyanate, (ii) a first polyol comprising a first polymer chain consisting essentially of propylene oxide units and alkylene oxide units selected from ethylene oxide, butylene oxide and mixtures thereof in a weight ratio of propylene oxide units to alkylene oxide units in the range of from about 90:10 to about 25:75, the polymer chain being terminally capped with the ethylene oxide units, the first polyol having a primary hydroxyl content of at least about 70% based on the total hydroxyl content of the first polyol, (iii) water (iv) a surfactant and (v) a catalyst to form a foamable reaction mixture; and (b) expanding the foamable reaction mixture to produce the free-rise polyurethane foam.

1 . A process for producing a free-rise polyurethane foam having a density of less than or equal to about 0.75 pcf, the process comprising the steps of:
 (a) contacting: (i) an isocyanate, (ii) a first polyol comprising a first polymer chain consisting essentially of propylene oxide units and alkylene oxide units selected from ethylene oxide, butylene oxide and mixtures thereof in a weight ratio of propylene oxide units to alkylene oxide units in the range of from about 90:10 to about 25:75, the polymer chain being terminally capped with the ethylene oxide units, the first polyol having a primary hydroxyl content of at least about 70% based on the total hydroxyl content of the first polyol, (iii) water (iv) a surfactant and (v) a catalyst to form a foamable reaction mixture; and   (b) expanding the foamable reaction mixture to produce the free-rise polyurethane foam.   
     
     
         2 . The process defined in  claim 1 , wherein the alkylene oxide units in the first polyol consist of propylene oxide. 
     
     
         3 . The process defined in  claim 1 , wherein the weight ratio of propylene oxide units to alkylene oxide units in the first polyol is from about 90:10 to about 70:30. 
     
     
         4 - 5 . (canceled) 
     
     
         6 . The process defined in  claim 1 , wherein the primary hydroxyl content in the first polyol is at least about 75% based on the total hydroxyl content of the first polyol. 
     
     
         7 - 12 . (canceled) 
     
     
         13 . The process defined in  claim 1 , wherein the first polyol has a molecular weight in the range of from about 2,500 to about 15,000. 
     
     
         14 - 16 . (canceled) 
     
     
         17 . The process defined in  claim 1 , wherein the second polyol is present up to 40 weight percent of the total polyol content in the reaction mixture. 
     
     
         18 - 20 . (canceled) 
     
     
         21 . The process defined in claim  16 , wherein the second polymer is present up to 20 weight percent of the total polyol content in the reaction mixture. 
     
     
         22 . The process defined in  claim 1 , wherein OH functionality for polyol content in the reaction mixture is in the range of from about 2 to about 4. 
     
     
         23 . The process defined in  claim 1 , wherein water is used in an amount of at least about 10 parts by weight per 100 parts by weight polyol in the reaction mixture. 
     
     
         24 - 25 . (canceled) 
     
     
         26 . The process defined in  claim 1 , wherein water is used in an amount in the range of from about 17 parts by weight to about 35 parts by weight per 100 parts by weight polyol in the reaction mixture. 
     
     
         27 . The process defined in  claim 1 , wherein the reaction mixture is substantially completely free of added CO 2 . 
     
     
         28 . The process defined in  claim 1 , wherein the reaction mixture is substantially completely free of added organic blowing agents. 
     
     
         29 . The process defined in  claim 1 , wherein the catalyst is an amine catalyst. 
     
     
         30 . The process defined in  claim 1 , wherein the catalyst is used in an amount of up to about 1 part by weight per 100 parts by weight polyol in the reaction mixture. 
     
     
         31 - 32 . (canceled) 
     
     
         33 . The process defined in  claim 1 , wherein the catalyst is used in an amount in the range of from about 0.25 parts by weight to about 0.35 parts by weight per 100 parts by weight polyol in the reaction mixture. 
     
     
         34 . The process defined in  claim 1 , wherein the isocyanate is used in an amount to provide an isocyanate index less than or equal to about 100. 
     
     
         35 . The process defined in  claim 1 , wherein the isocyanate is used in an amount to provide an isocyanate index in the range of from about 45 to about 75. 
     
     
         36 - 37 . (canceled) 
     
     
         38 . The process defined in  claim 1 , wherein the reaction mixture further comprises a surfactant. 
     
     
         39 . The process defined in  claim 1 , wherein the surfactant is used in an amount of up to about 5 parts by weight per 100 parts by weight polyol in the reaction mixture. 
     
     
         40 - 42 . (canceled) 
     
     
         43 . The process defined in  claim 1 , wherein the free-rise polyurethane foam has a density of in the range of from about 0.30 pcf to about 0.75 pcf. 
     
     
         44 - 47 . (canceled) 
     
     
         48 . A free-rise polyurethane foam produced by the process of  claim 1 . 
     
     
         49 . A free-rise flexible polyurethane foam: (i) having a density less than or equal to about 0.75 pcf, (ii) having a low exotherm during production, and (iii) being substantially completely free of a metal catalyst. 
     
     
         50 . The free-rise flexible polyurethane foam defined in  claim 49 , wherein the density is less than about 0.75 pcf. 
     
     
         51 . The free-rise flexible polyurethane foam defined in  claim 49 , wherein the density is in the range from about 0.50 pcf to about 0.75 pcf. 
     
     
         52 . The free-rise flexible polyurethane foam defined in  claim 49 , wherein the density is in the range from about 0.50 pcf to about 0.65 pcf. 
     
     
         53 . The free-rise flexible polyurethane foam defined in  claim 49 , wherein the foam is substantially completely free of a tin catalyst.