Polyurethane elastomers from HDI prepolymers with reduced content of free HDI monomers

Abstract

Polyurethane prepolymers with reduced amount of unreacted monomeric hexamethylene 1,6-diisocyanate (HDI) are provided. Also provided are polyurethane elastomers obtained by mixing the polyurethane prepolymers having reduced amount of unreacted monomeric HDI with amine and/or hydroxy chain extenders and durable, resilient, colorfast golf ball covers obtained therefrom. Rolls, wheels and tires obtained from the polyurethane elastomers are also provided.

What is claimed:  
     
         1 . A process for preparing polyurethane prepolymers with below 2% by weight of residual 1,6-hexamethylene diisocyanate monomer (HDI) comprising 
 a) reacting a stoichiometric excess of HDI with one or more polyols; and    b)distilling the reaction product in one or more agitated film evaporators in series under vacuum.    
     
     
         2 . The process of  claim 1  wherein the level of unreacted HDI is reduced to below about 0.5% by weight.  
     
     
         3 . The process of  claim 1  wherein the level of unreacted HDI is reduced to below about 0.1% by weight.  
     
     
         4 . The process of  claim 1  wherein the NCO:OH ratio is about 2:1 to about 30:1 and the level of unreacted HDI is reduced to below about 2% by weight.  
     
     
         5 . The process of  claim 1  wherein the polyol component is a polyol having a functionality of about 1.9 to about 2.3.  
     
     
         6 . The process of  claim 5  wherein the polyol is selected from the group consisting of polyesters, polycaprolactones, polyethers, polycarbonates, hydrocarbon polyols and mixtures thereof.  
     
     
         7 . The process of  claim 1  wherein the polyol is selected from the group consisting of a polyester of adipic acid, a polyether of ethylene oxide, propylene oxide or tetrahydrofuran, a polycaprolactone, a polycarbonate, a hydrocarbon polyol and mixtures thereof, the polyol having a molecular weight from 100 to 12,000 and having a functionality of about 1.9 to about 2.3.  
     
     
         8 . The process of  claim 1  wherein the distillation step comprises at least three agitated film vacuum evaporator distillation stages in series.  
     
     
         9 . A polyurethane prepolymer comprising the reaction product of one or more polyols and a stoichiomentric excess of HDI diisocyanate monomer at an NCO:OH ratio in the range of from about 2:1 to about 30:1 wherein the unreacted HDI diisocyanate monomer is removed by a process comprising distilling the reaction product in one or more agitated film evaporators in series under vacuum.  
     
     
         10 . The polyurethane prepolymer of  claim 9  containing less than about 2% by weight of unreactcd HDI monomer.  
     
     
         11 . The polyurethane prepolymer of  claim 9  containing less than about 0.5% by weight of unreacted HDI monomer.  
     
     
         12 . The polyurethane prepolymer of  claim 9  containing less than about 2% by weight of unreacted HDI monomer and containing an NCO content greater than about 70% of the theoretical NCO content for pure ABA structure.  
     
     
         13 . The polyurethane prepolymer of  claim 9  containing less than about 0.1% by weight of unreacted HDI monomer and containing an NCO content greater than about 80% of the theoretical NCO content for pure ABA structure.  
     
     
         14 . The polyurethane prepolymer of  claim 9  wherein the polyol component is a polyol having a functionality of about 1.9 to about 2.3.  
     
     
         15 . The polyurethane prepolymer of  claim 14  wherein the polyol is selected from the group consisting of polyesters, polycaprolactones, polyethers, polycarbonates, hydrocarbon polyols and mixtures thereof.  
     
     
         16 . The polyurethane prepolymer of  claim 9  wherein the polyol is selected from the group consisting of a polyester of adipic acid, a polyether of ethylene oxide, propylene oxide or tetrahydrofuran, a polycaprolactone, a polycarbonate, a hydrocarbon polyol and mixtures thereof, the polyol having a molecular weight from 100 to 12,000 and having a functionality of about 1.9 to about 2.3.  
     
     
         17 . A polyurethane prepolymer terminated with HDI, the prepolymer comprising no more than about 2% by weight free HDI and having at least about 70% of the theoretical NCO content for pure ABA structure  
     
     
         18 . A polyurethane elastomer comprising the reaction product of (a) a prepolymer terminated with HDI, said prepolymer comprising no more than about 2 wt. % free HDI and having at least 70% of theoretical NCO content for pure ABA structure with (b) one or more hydroxy or amine-functional chain extenders, wherein the equivalent ratio of chain extender to prepolymer is in the range of from about 0.7:1 to about 1.2:1.  
     
     
         19 . The polyurethane elastomer of  claim 18  wherein the HDI-terminated prepolymer comprises less than about 0.5% by weight of unreacted HDI monomer.  
     
     
         20 . The polyurethane elastomer of  claim 18  wherein the HDI-terminated prepolymer comprises the reaction product of one or more polyols and a stoichiomentric excess of HDI diisocyanate monomer at an NCO:OH ratio in the range of from about 2:1 to about 30:1  
     
     
         21 . The polyurethane elastomer of  claim 19  wherein the polyol component is a polyol having a functionality of about 1.9 to about 2.3.  
     
     
         22 . The polyurethane elastomer of  claim 21  wherein the polyol is selected from the group consisting of polyesters, polycaprolactones, polyethers, polycarbonates, hydrocarbon polyols and mixtures thereof.  
     
     
         23 . The polyurethane elastomer of  claim 18  wherein the polyol is selected from the group consisting of a polyester of adipic acid, a polyether of ethylene oxide, propylene oxide or tetrahydrofuran, a polycaprolactone, a polycarbonate, a hydrocarbon polyol and mixtures thereof, the polyol having a molecular weight from 100 to 12,000 and having a functionality of about 1.9 to about 2.3.  
     
     
         24 . The polyurethane elastomer of  claim 18  wherein the chain extender is selected from the group consisting of 1,4-butanediol, 1,3-propanediol, ethylene glycol, 1,6-hexanediol, hydroquinone-bis-hydroxyethyl ether, resorcinol di (beta-hydroxyethyl) ether, resorcinol di (beta-hydroxypropyl) ether, 1,4-cyclohexane dimethanol, an aliphatic triols, an aliphatic tetrols, 4,4′-methylene-bis(3-chloroaniline), 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), 4,4′-methylene-bis(2,6-diethylaniline), diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-amino-benzoate, methylenedianiline, methylenedianiline-sodium chloride complex and mixtures thereof.  
     
     
         25 . The polyurethane elastomer of  claim 18  wherein the chain extender is selected from the group consisting of 1,4-butanediol, 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), 4,4′-methylene-bis(2,6-diethylaniline), diethyl toluene diamine and mixtures thereof.  
     
     
         26 . The polyurethane elastomer of  claim 18  wherein the chain extender is 4,4′-methylene-bis(3-chloro-2,6-diethylaniline).  
     
     
         27 . A golf ball comprising a core and a cover, the cover comprising a polyurethane elastomer, the polyurethane elastomer comprising the reaction product of (a) a HDI-terminated prepolymer comprising the reaction product of one or more polyols with a stoichiometric excess of HDI diisocyanate monomer wherein unreacted HDI diisocyanate monomer is removed to less than about 2 wt. % and (b) at least one hydroxy or amine functional chain extender.  
     
     
         28 . The golf ball of  claim 27  wherein in the prepolymer the unreacted HDI diisocyanate monomer is removed to less than about 0.5% by weight.  
     
     
         29 . The golf ball of  claim 27  wherein the HDI-terminated prepolymer comprises the reaction product of one or more polyols and a stoichiomentric excess of HDI diisocyanate monomer at an NCO:OH ratio in the range of from about 2:1 to about 30:1  
     
     
         30 . The golf ball of  claim 27  wherein the polyol component of the HDI-terminated prepolymer reaction product is a polyol having a functionality of about 1.9 to about 2.3.  
     
     
         31 . The golf ball of  claim 30  wherein the polyol is selected from the group consisting of polyesters, polycaprolactones, polyethers, polycarbonates, hydrocarbon polyols and mixtures thereof.  
     
     
         32 . The golf ball of  claim 27  wherein the polyol component of the HDI-terminated prepolymer reaction product is selected from the group consisting of a polyester of adipic acid, a polyether of ethylene oxide, propylene oxide or tetrahydrofuran, a polycaprolactone, a polycarbonate, a hydrocarbon polyol and mixtures thereof, the polyol having a molecular weight from 100 to 12,000 and having a functionality of about 1.9 to about 2.3.  
     
     
         33 . The golf ball of  claim 27  wherein the chain extender of the polyurethane elastomer is selected from the group consisting of 1,4-butanediol, 1,3-propanediol, ethylene glycol, 1,6-hexanediol, hydroquinone-bis-hydroxyethyl ether, resorcinol di (beta-hydroxyethyl) ether, resorcinol di (beta-hydroxypropyl) ether, 1,4-cyclohexane dimethanol, an aliphatic triols, an aliphatic tetrols, 4,4′-methylene-bis(3-chloroaniline), 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), 4,4′-methylene-bis(2,6-diethylaniline), diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-amino-benzoate, methylenedianiline, methylenedianiline-sodium chloride complex and mixtures thereof.  
     
     
         34 . The golf ball of  claim 27  wherein the chain extender of the polyurethane elastomer is selected from the group consisting of 1,4-butanediol, 1,3-propanediol, ethylene glycol, 1,6-hexanediol and mixtures thereof.  
     
     
         35 . A wheel or roll comprising a core and a polyurethane cover wherein the cover comprises the reaction product of: 
 (a) a HDI-terminated prepolymer comprising the reaction product of one or more polyols with a stoichiometric excess of HDI diisocyanate monomer wherein unreacted HDI diisocyanate monomer is removed to less than about 2% by weight; and    (b) at least one hydroxy or amine functional chain extender.    
     
     
         36 . The wheel or roll of  claim 35  wherein in the HDI-terminated prepolymer the unreacted HDI diisocyanate monomer is removed to less than about 0.5% by weight.  
     
     
         37 . The wheel or roll of  claim 35  wherein the HDI-terminated prepolymer comprises the reaction product of one or more polyols and a stoichiomentric excess of HDI diisocyanate monomer at an NCO:OH ratio in the range of from about 2:1 to about 30:1  
     
     
         38 . The wheel or roll of  claim 35  wherein the polyol component of the HDI-terminated prepolymer reaction product is a polyol having a functionality of about 1.9 to about 2.3.  
     
     
         39 . The wheel or roll of  claim 38  wherein the polyol is selected from the group consisting of polyesters, polycaprolactones, polyethers, polycarbonates, hydrocarbon polyols and mixtures thereof.  
     
     
         40 . The wheel or roll of  claim 35  wherein the polyol component of the HDI-terminated prepolymer reaction product is selected from the group consisting of a polyester of adipic acid, a polyether of ethylene oxide, propylene oxide or tetrahydrofuran, a polycaprolactone, a polycarbonate, a hydrocarbon polyol and mixtures thereof, the polyol having a molecular weight from 100 to 12,000 and having a functionality of about 1.9 to about 2.3.  
     
     
         41 . The wheel or roll of  claim 35  wherein the chain extender of the polyurethane elastomer is selected from the group consisting of 1,4-butanediol, 1,3-propanediol, ethylene glycol, 1,6-hexanediol, hydroquinone-bis-hydroxyethyl ether, resorcinol di (beta-hydroxyethyl) ether, resorcinol di (beta-hydroxypropyl) ether, 1,4-cyclohexane dimethanol, an aliphatic triols, an aliphatic tetrols, 4,4′-methylene-bis(3-chloroaniline), 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), 4,4′-methylene-bis(2,6-diethylaniline), diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-amino-benzoate, methylenedianiline, methylenedianiline-sodium chloride complex and mixtures thereof.  
     
     
         42 . The wheel or roll of  claim 35  wherein the chain extender of the polyurethane elastomer is selected from the group consisting of 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), 4,4′-methylene-bis(2,6-diethylaniline), diethyl toluene diamine and mixtures thereof.  
     
     
         43 . The wheel or roll of  claim 35  wherein the chain extender of the polyurethane elastomer comprises 4,4′-methylene-bis(3-chloro-2,6-diethylaniline).