Organometallic-free polyurethanes having low extractables

Abstract

Breathable thermoplastic polyurethanes are prepared from the reaction of a polyol component, a polyisocyanate component, and a chain extender in the presence of a metal-free catalyst. The metal-free catalyst comprises a polyalcohol amine, a tertiary amine catalyst, or a combination thereof. The polyurethanes of the present invention are suitable for film applications as they form breathable films which are permeable to water vapor but not air or water. The polyurethane compositions are substantially metal-free, have low extractables, and excellent melt strength.

1 . A thermoplastic polyurethane polymer, comprising the reaction product of: 
 a) at least one polyol;    b) at least one polyisocyanate;    c) at least one chain extender; and    d) at least one polyalcohol amine catalyst.    
     
     
         2 . A polyurethane polymer according to  claim 1 , wherein said polyurethane polymer has a nitrogen content from said polyalcohol amine catalyst in an amount from about 0.075 to about 2 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender, and said catalyst.  
     
     
         3 . A polyurethane polymer according to  claim 2 , wherein said polyalcohol amine catalyst has the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  independently, represent linear or branched, alkyl, cycloalkyl, or alkylaryl groups having from about 1 to about 20 carbon atoms, and wherein R 3  represents hydrogen, linear or branched, alkyl, cycloalkyl, or alkylaryl groups having from 1 to about 20 carbon atoms, and wherein at least said R 1 , R 2  and R 3  collectively include at least two hydroxyl groups.  
     
     
         4 . A polyurethane polymer according to  claim 2 , wherein said polyalcohol amine catalyst a) has the formula:  
       
         
           
           
               
               
           
         
       
       wherein said R 4 , R 5 , R 6 , R 7 , R 8  and R 9 , independently, represent linear or branched alkyl, cycloalkyl or alkylaryl groups having from 1 to about 20 carbon atoms, wherein said R 7  or said R 8 , or a combination thereof can additionally represent hydrogen, with the proviso that the R groups other than hydrogen collectively have at least two hydroxyl groups, or b) is a polyalcohol-containing polyamide adduct of alkylene oxide having an equivalent weight of about 100 and about 5,000.  
     
     
         5 . A polyurethane polymer according to  claim 1 , wherein said polyurethane polymer is substantially free of an organometallic catalyst.  
     
     
         6 . A polyurethane polymer according to  claim 3 , wherein said polyalcohol amine is triethanolamine, diethanolamine, diisopropanolamine, N-methyl diethanolamine, N-ethyl diethanolamine, N-propyl diethanolamine, N-isopropyl diethanolamine, N-butyl diethanolamine, N-isobutyl diethanolamine, N-oleyl diethanolamine, N-stearyl diethanolamine, N-allyl diethanolamine, N-methyl diisopropanolamine, N-ethyl diisopropanolamine, N-propyl diisopropanolamine, N-butyl diisopropanolamine, cyclohexyl diisopropanolamine, bis(2-hydroxyethyl)amino-2-propanol, 2-bis(2-hydroxyethyl)amino-2-(hydroxymethyl)-1,3-propanediol, 1,3-bis[tris(hydroxymethyl)methyl amino]propane, N,N′bis(hydroxyethylene)ethylenediamine, 1-[N,N-bis(2-hydroxyethyl)amino]-2-propanol, 1,4-bis(hydroxyethylpiperazine, 1-[2-(2-hydroxyethoxy)ethyl]piperazine, or 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol, or a combination thereof.  
     
     
         7 . A polyurethane polymer according to  claim 6 , wherein said polyalcohol amine catalyst is triethanolamine, bis(2-hydroxyethyl)amino-2-propanol, 2-bis(2-hydroxyethyl)amino-2-(hydroxymethyl)-1,3-propanediol, or 1,3-bis[tris(hydroxymethyl)methylamino]propane, or a combination thereof.  
     
     
         8 . A polyurethane polymer according to  claim 4 , wherein said polyalcohol amine is trimethylolmelamine, hexamethylolmelamine, or dimethylolmelamine, or a combination thereof.  
     
     
         9 . A polyurethane polymer according to  claim 2 , wherein a molar ratio of total hydroxyl groups of the at least one chain extender to total hydroxyl groups of the at least one polyol is from about 0.1 to about 3.0, and wherein a molar ratio of polyisocyanate functional groups to total hydroxyl groups of the at least one polyol and at least one chain extender is from about 0.95 to about 1.10.  
     
     
         10 . A polyurethane polymer according to  claim 9 , wherein said chain extender is an organic diol or glycol having a total of from 2 to about 20 carbon atoms, and wherein said at least one polyol includes a polyether polyol.  
     
     
         11 . A polyurethane polymer according to  claim 10 , wherein said chain extender is an alkane diol, cycloaliphatic diol, or an alkyl aryl diol, and wherein said at least one polyisocyanate is a diisocyanate, wherein said polyurethane polymer has said nitrogen content from said polyalcohol amine catalyst in an amount from about 0.095 to about 1.5 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender and said catalyst.  
     
     
         12 . A polyurethane polymer according to  claim 6 , wherein said polyurethane polymer has said nitrogen content from said polyalcohol amine catalyst in an amount from about 0.085 to about 1.75 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender and said catalyst.  
     
     
         13 . A breathable polyurethane article, comprising: 
 a polyurethane polymer comprising the reaction product of:    a) at least one polyol;    b) at least one polyisocyanate;    c) at least one chain extender; and    d) at least one polyalcohol amine catalyst.    
     
     
         14 . A polyurethane article according to  claim 13 , wherein said polyurethane article is a coating layer on a substrate, or a film, wherein said substrate comprises a woven or non-woven, natural or synthetic fiber, or a combination thereof.  
     
     
         15 . A polyurethane article according to  claim 1   4 , wherein said film or said coating is from about 0.5 mils to about 10 mils thick, and wherein said film or coating has a moisture vapor transmission rate of greater than about 100 g/m 2  per day.  
     
     
         16 . A polyurethane article according to  claim 13 , wherein said polyurethane polymer has a nitrogen content from said polyalcohol amine catalyst in an amount from about 0.075 to about 2.0 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender and said catalyst.  
     
     
         17 . A polyurethane article according to  claim 16 , wherein said polyalcohol amine catalyst has the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  independently, represent linear or branched, alkyl, cycloalkyl, or alkylaryl groups having from about 1 to about 20 carbon atoms, and wherein R 3  represents hydrogen, linear or branched, alkyl, cycloalkyl, or alkylaryl groups having from 1 to about 20 carbon atoms, and wherein at least said R 1 , R 2  and R 3  collectively include at least two hydroxyl groups.  
     
     
         18 . A polyurethane article according to  claim 16 , wherein said polyalcohol amine catalyst a) has the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 4 , R 5 , R 6 , R 7 , R 8  and R 9 , independently, represent linear or branched alkyl, cycloalkyl or alkylaryl groups having from 1 to about 20 carbon atoms, wherein said R 7  or said R 8 , or a combination thereof can additionally represent hydrogen, with the proviso that the R groups other than hydrogen collectively have at least two hydroxyl groups thereon, or b) is a polyalcohol-containing polyamide adduct of alkylene oxide having an equivalent weight of about 100 and about 5,000.  
     
     
         19 . A polyurethane article according to  claim 13 , wherein said polyurethane polymer is substantially free of an organometallic catalyst.  
     
     
         20 . A polyurethane article according to  claim 17 , wherein said polyalcohol amine is triethanolamine, diethanolamine, diisopropanolamine, N-methyl diethanolamine, N-ethyl diethanolamine, N-propyl diethanolamine, N-isopropyl diethanolamine, N-butyl diethanolamine, N-isobutyl diethanolamine, N-oleyl diethanolamine, N-stearyl diethanolamine, N-allyl diethanolamine, N-methyl diisopropanolamine, N-ethyl diisopropanolamine, N-propyl diisopropanolamine, N-butyl diisopropanolamine, cyclohexyl diisopropanolamine, bis(2-hydroxyethyl)amino-2-propanol, 2-bis(2-hydroxyethyl)amino-2-(hydroxymethyl)-1,3-propanediol, 1,3-bis[tris(hydroxymethyl)methyl amino]propane, N,N′bis(hydroxyethylene)ethylenediamine, 1-[N,N-bis(2-hydroxyethyl)amino]-2-propanol, 1,4-bis(hydroxyethylpiperazine, 1-[2-(2-hydroxyethoxy)ethyl]piperazine, or 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol, or a combination thereof.  
     
     
         21 . A polyurethane article according to  claim 20 , wherein said polyalcohol amine catalyst is triethanolamine, bis(2-hydroxyethyl)amino-2-propanol, 2-bis(2-hydroxyethyl)amino-2-(hydroxymethyl)-1,3-propanediol, 1,3-bis[tris(hydroxymethyl)methylamino]propane, or a combination thereof.  
     
     
         22 . A polyurethane article according to  claim 18 , wherein said polyalcohol amine is trimethylolmelamine, hexamethylolmelamine, or dimethylolmelamine, or a combination thereof.  
     
     
         23 . A polyurethane article according to  claim 1   6 , wherein a molar ratio of total hydroxyl groups of the at least one chain extender to total hydroxyl groups of the at least one polyol is from about 0.1 to about 3.0, and wherein a molar ratio of polyisocyanate functional groups to total hydroxyl groups of the at least one polyol and at least one chain extender is from about 0.95 to about 1.10.  
     
     
         24 . A polyurethane article according to  claim 23 , wherein said chain extender is an organic diol or glycol having a total of from 2 to about 20 carbon atoms, and wherein said at least one polyol includes a polyether polyol.  
     
     
         25 . A polyurethane article according to  claim 24 , wherein said chain extender is an alkane diol, cycloaliphatic diol, or an alkyl aryl diol, and wherein said at least one polyisocyanate is a diisocyanate.  
     
     
         26 . A polyurethane article according to  claim 25 , wherein said polyurethane polymer has said nitrogen content from said polyalcohol amine catalyst in an amount from about 0.085 to about 1.75 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender and said catalyst.  
     
     
         27 . A polyurethane article according to  claim 24 , wherein said polyurethane article is a coating layer on a substrate, or a film, wherein said substrate comprises a woven or non-woven, natural or synthetic fiber, or a combination thereof.  
     
     
         28 . A polyurethane article according to  claim 27 , wherein said film or said coating is from about 0.5 mils to about 10 mils thick, and wherein said film or coating has a moisture vapor transmission rate of greater than about 200 g/m 2  per day.  
     
     
         29 . A breathable polyurethane article, comprising a polyurethane polymer comprising the reaction product of: 
 a) at least one polyol;    b) at least one polyisocyanate;    c) at least one chain extender; and    d) at least one tertiary amine catalyst, wherein said polyurethane polymer has a nitrogen content from said tertiary amine catalyst in an amount from about 0.06 to about 2 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender, and said catalyst.    
     
     
         30 . A polyurethane article according to  claim 29 , wherein said polyurethane article is a coating layer on a substrate, or a film, wherein said substrate comprises a woven or non-woven, natural or synthetic fiber, or a combination thereof.  
     
     
         31 . A polyurethane article according to  claim 30 , wherein said film or said coating is from about 0.5 mils to about 10 mils thick, wherein said film or coating has a moisture vapor transmission rate of greater than about 100 g/m 2  per day, and wherein said tertiary amine is diazabicyclooctane, tridodecylamine, trihexadecylamine, or an N,N′-dimethylalkyl amine, or a combination thereof.  
     
     
         32 . A polyurethane article according to  claim 29 , wherein said polyurethane polymer is substantially free of an organometallic catalyst.  
     
     
         33 . A polyurethane article according to  claim 32 , wherein a molar ratio of total hydroxyl groups of the at least one chain extender to total hydroxyl groups of the at least one polyol is from about 0.1 to about 3.0, and wherein a molar ratio of polyisocyanate functional groups to total hydroxyl groups of the at least one polyol and at least one chain extender is from about 0.95 to about 1.10.  
     
     
         34 . A polyurethane article according to  claim 33 , wherein said chain extender is an organic diol or glycol having a total of from 2 to about 20 carbon atoms, and wherein said at least one polyol includes a polyether polyol.  
     
     
         35 . A polyurethane article according to  claim 34 , wherein said chain extender is an alkane diol, cycloaliphatic diol, or an alkyl aryl diol, and wherein said at least one polyisocyanate is a diisocyanate.  
     
     
         36 . A polyurethane article according to  claim 35 , wherein said polyurethane article is a coating layer on a substrate, or a film, wherein said substrate comprises a woven or non-woven, natural or synthetic fiber, or a combination thereof.  
     
     
         37 . A polyurethane article according to  claim 36 , wherein said film or said coating is from about 0.5 mils to about 10 mils thick, and wherein said film or coating has a moisture vapor transmission rate of greater than about 200 g/m 2  per day.  
     
     
         38 . A method for preparing a thermoplastic polyurethane polymer, comprising the steps of: 
 reacting at least one polyol, at least one polyisocyanate, at least one chain extender, and at least one polyalcohol amine catalyst.    
     
     
         39 . A method according to  claim 38 , wherein said polyurethane polymer has a nitrogen content from said polyalcohol amine catalyst in an amount from about 0.075 to about 2 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender and said catalyst.  
     
     
         40 . A method according to  claim 39 , wherein said polyalcohol amine catalyst has the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  and R 2  independently, represent linear or branched, alkyl, cycloalkyl, or alkylaryl groups having from about 1 to about 20 carbon atoms, and wherein R 3  represents hydrogen, linear or branched, alkyl, cycloalkyl, or alkylaryl groups having from 1 to about 20 carbon atoms, and wherein at least said R 1 , R 2  and R 3  collectively include at least two hydroxyl groups.  
     
     
         41 . A method according to  claim 40 , wherein said polyalcohol amine catalyst is triethanolamine, bis(2-hydroxyethyl)amino-2-propanol, 2-bis(2-hydroxyethyl)amino-2-(hydroxymethyl)-1,3-propanediol, or 1,3-bis[tris(hydroxymethyl)methylamino]propane, or a combination thereof.  
     
     
         42 . A method according to  claim 41 , wherein said chain extender is an organic diol or glycol having a total of from 2 to about 20 carbon atoms, and wherein said at least one polyol includes a polyether polyol, and wherein said polyurethane polymer has a nitrogen content from said polyalcohol amine catalyst in an amount from about 0.085 to about 1.75 mol % based on the total moles of said polyol, said polyisocyanate, said chain extender and said catalyst.