Low nucleation temperature polythioether prepolymers and uses thereof

Abstract

Polythioether prepolymers that have a low nucleation temperature are disclosed. The polythioether prepolymers are stable at low temperature storage conditions for an extended period of time. Compositions prepared using the low nucleation temperature polythioether prepolymers are useful as sealants.

What is claimed is: 
     
         1 . A polythioether prepolymer comprising a moiety having the structure of Formula (3): 
       
         
           
           
               
               
           
         
       
        wherein,
 (a) n is an integer from 1 to 60; 
 (b) each A is independently selected from a moiety of Formula (4), a moiety of Formula (5), and a moiety of Formula (6): 
                     
                     
                     
 (c) each D is independently selected from a moiety of Formula (7), a moiety of Formula (8), and a moiety of Formula (9): 
                     
                     
                     
 (d) wherein,
 (i) c is an integer from 1 to 3; 
 (ii) each R 1  is independently selected from substituted C 2-10  alkanediyl, C 2-10  heteroalkanediyl, substituted C 2-10  heteroalkanediyl, and —[(CR 2 ) p —X—] q —(CR 2 ) r —, wherein,
 p is an integer from 1 to 6; 
 q is an integer from 1 to 5; 
 r is an integer from 2 to 10; 
 each X is independently selected from O and S; and 
 each R is independently selected from hydrogen, C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl; 
 
 (iii) each R 2  is independently selected from substituted C 2-10  alkanediyl, C 2-10  heteroalkanediyl, substituted C 2-10  heteroalkanediyl, and —[(CR 2 ) p —X—] q —(CR 2 ) r —, wherein,
 p is an integer from 1 to 6; 
 q is an integer from 1 to 5; 
 r is an integer from 2 to 10; 
 each X is independently selected from O and S; and 
 each R is independently selected from hydrogen, C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl; 
 
 (iv) B represents a core of a z-valent, polythiol polyfunctionalizing agent B(—R 3 —SH) z  or a polyfunctional thiol-reactive polyfunctionalizing agent B(—R 3 —R 4 ) z , wherein,
 z is an integer from 3 to 6; and 
 each R 3  is independently selected from C 1-10  alkanediyl, C 1-10  heteroalkanediyl, substituted C 1-10  alkanediyl, and substituted C 1-10  heteroalkanediyl; and 
 each R 4  is a thiol-reactive group; and 
 
 (v) each R 4a  is independently a divalent moiety comprising a group derived from a reaction of a thiol-reactive group R 4  with a thiol group; and 
 
 (e) wherein,
 (i) at least one of R 1  and R 2  is present being selected from substituted C 2-10  alkanediyl, substituted C 2-10  heteroalkanediyl, and —[(CR 2 ) p —X—] q —(CR 2 ) r —, wherein,
 p is an integer from 1 to 6; 
 q is an integer from 1 to 5; 
 r is an integer from 2 to 10; 
 each X is independently selected from O and S; and 
 each R is independently selected from hydrogen, C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl, wherein 
 at least one R is selected from C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl; and/or 
 
 (ii) the polythioether prepolymer comprises two or more moieties having the structure of Formula (10): 
                     
  wherein,
 a is an integer from 1 to 6; 
 each X is independently selected from O and S; and 
 the value of a in a first moiety of Formula (10) is different than the value of a in a second moiety of Formula (10). 
 
 
 
     
     
         2 . The polythioether prepolymer of  claim 1 , wherein (i) at least one of R 1  and R 2  is selected from substituted C 2-10  heteroalkanediyl, and —[(CR 2 ) p —X—] q —(CR 2 ) r —, wherein,
 p is an integer from 1 to 6; 
 q is an integer from 1 to 5; 
 r is an integer from 2 to 10; 
 each X is independently selected from O and S; 
 each R is independently selected from hydrogen, C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl; wherein 
 at least one R is selected from C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl. 
 
     
     
         3 . The polythioether prepolymer of  claim 1 , wherein (ii) the polythioether prepolymer comprises two or more moieties having the structure of Formula (10): 
       
         
           
           
               
               
           
         
       
       
         wherein,
 a is an integer from 1 to 6; 
 X is selected from O and S; and 
 at least one of the moieties of Formula (10) is different than at least one of the other moieties of Formula (10). 
 
       
     
     
         4 . The polythioether prepolymer of  claim 1 , wherein the thiol-reactive group R 4  is selected from an alkenyl group, an alkynyl group, an epoxy group, an isocyanate group, or a Michael acceptor group. 
     
     
         5 . The polythioether prepolymer of  claim 1 , wherein R 4a  is selected from —CH 2 —CH 2 —, —CH═CH—, —C(═O)—NH—, —CH 2 —CH(—OH)—, and —(CH 2 ) 2 —EW—, where EW is an electron withdrawing group. 
     
     
         6 . The polythioether prepolymer of  claim 1 , wherein the thiol-reactive group R 4  is an alkenyl group; and R 4a  is —CH 2 —CH 2 —. 
     
     
         7 . The polythioether prepolymer of  claim 1 , wherein the polythioether prepolymer comprises a thiol-terminated polythioether prepolymer of Formula (3a): 
       
         
           
           
               
               
           
         
       
       
         wherein,
 n, A, and D are defined as for Formula (1); 
 each branch, if present, of the thiol-terminated polythioether prepolymer is terminated in a moiety —[—D—A—] n1 —H; and 
 n1 is an integer from 0 to 10. 
 
       
     
     
         8 . The polythioether prepolymer of  claim 1 , wherein the polythioether prepolymer comprises a thiol-reactive polythioether prepolymer of Formula (3b): 
       
         
           
           
               
               
           
         
       
       
         wherein,
 n, A, and D are defined as for Formula (3); and 
 each D 1  is independently selected from a moiety of Formula (7b), a moiety of Formula (8b), and a moiety of Formula (9b): 
                     
                     
                     
 wherein c, z, R 1 , R 2  R 4 , and R 4a  are defined as for Formula (7), Formula (8), or Formula (9). 
 
       
     
     
         9 . The polythioether prepolymer of  claim 1 , wherein the polythioether prepolymer has a reactive functionality from 2.1 to 2.9. 
     
     
         10 . The polythioether prepolymer of  claim 1 , wherein the polythioether prepolymer has a sulfur content from 10 wt% to 35 wt%, where wt% is based on the total weight of the polythioether prepolymer. 
     
     
         11 . The polythioether prepolymer of  claim 1 , wherein the molar ratio of residues from nonlinear monomers and/or adducts to residues from linear dithiol and/or dialkenyl monomers in the polythioether prepolymer is from 0.05:1 to 1.2:1. 
     
     
         12 . A polythioether prepolymer, wherein the polythioether prepolymer comprises the reaction product of reactants comprising:
 (a) a polythiol monomer, wherein the polythiol monomer comprises a dithiol monomer of Formula (4a), a polythiol polyfunctionalizing agent of Formula (5a), a dithiol adduct of Formula (6a), or a combination of any of the foregoing;                                                                     wherein each R 1  and each R 2  is independently selected from C 2-10  heteroalkanediyl, substituted C 2-   10  alkanediyl, substituted C 2-10  heteroalkanediyl, and —[(CR 2 ) p —X—] q —(CR 2 ) r —,
 wherein,
 p is an integer from 1 to 6; 
 q is an integer from 1 to 5; 
 r is an integer from 2 to 10; 
 each X is independently selected from O and S; and 
 
 each R is independently selected from hydrogen, C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl; 
 each R 4a  independently comprises a group derived from a reaction of a thiol-reactive group R 4  with a thiol group; 
 
 B represents a core of a z-valent, polythiol polyfunctionalizing agent B(—R 3 —SH) z   
 each R 3  is independently selected from C 1-10  alkanediyl, C 1-10  heteroalkanediyl, substituted C 1-10  alkanediyl, and substituted C 1-10  heteroalkanediyl; 
 
 c is an integer from 1 to 3; and 
 z is an integer from 3 to 6; and 
   (b) a polyfunctional thiol-reactive monomer, wherein the polyfunctional thiol-reactive monomer comprises a difunctional thiol-reactive monomer of Formula (7a), a polyfunctional thiol-reactive polyfunctionalizing agent of Formula (8a), a difunctional thiol-reactive adduct of Formula (9a), or a combination of any of the foregoing;                                                                      wherein,
 R 1 , R 2 , B, R 3 , z, c, and R 4a  are as defined above and each R 4  is a thiol-reactive group; 
 (i) at least one of R 1  and R 2  is present being selected from substituted C 2-10  alkanediyl, substituted C 2-10  heteroalkanediyl, and —[(CR 2 ) p —X—] q —(CR 2 ) r —, wherein R, p, X, q and r are as defined above, wherein at least one R is selected from C 1-16  alkyl, C 1-16  heteroalkyl, substituted C 1-16  alkyl, and substituted C 1-16  heteroalkyl; and/or 
 (ii) the polythioether prepolymer comprises two or more moieties having the structure of Formula (10): 
                     
  wherein,
 a is an integer from 1 to 6; 
 each X is independently selected from O and S; and 
 the value of a in a first moiety of Formula (10) is different than the value of a in a second moiety of Formula (10). 
 
   
     
     
         13 . The polythioether prepolymer of  claim 12 , wherein, 
 (a) the polythiol monomer comprises DMDO (2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)), DMDS (2,2′ thiobis(ethan-1-thiol)), M-DMDS (methyl-substituted dimercaptodiethylsulfide), a DMDO/DEG-DVE (2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)/diethylene glycol divinyl ether) adduct, a DMDO/TMP-DAE (2,2-(ethane-1,2-diylbis(sulfanyl))bis(ethan-1-thiol)/2,2-bis(allyloxy)methyl)butan-1-ol) adduct, a DMDS/TMP-DAE (2,2′-thiobis(ethan-1-thiol)/2,2-bis(allyloxy)methyl)butan-1-ol) adduct, or a combination of any of the foregoing; and   (b) the polyfunctional thiol-reactive monomer comprises TAC (triallyl cyanurate), DEG-DVE (diethylene glycol divinyl ether), DVTMDS (divinyltetramethyldisiloxane), BAEF (bis([2-allyloxy)ethyl]formal), NFHT (3,3,4,4,5,5,6,6,6-nonafluorohexane-1-thiol), or a combination of any of the foregoing.   
     
     
         14 . A terminal-modified polythioether prepolymer, wherein the terminal-modified polythioether prepolymer comprises the reaction product of reactants comprising:
 (a) the polythioether prepolymer of  claim 1 ; and   (b) a compound comprising a terminal functional group and a terminal group reactive with the polythioether prepolymer of  claim 1 .   
     
     
         15 . A composition comprising the polythioether prepolymer of  claim 1 . 
     
     
         16 . A cured composition prepared from the composition of  claim 15 . 
     
     
         17 . A method of sealing a surface, comprising:
 applying the composition of  claim 15  to a surface; and   curing the applied composition to seal the surface.   
     
     
         18 . A sealant system comprising:
 a first part, wherein the first part comprises the polythioether prepolymer of  claim 1 ; and   a second part, wherein the second part comprises a curing agent, wherein the curing agent is reactive with the polythioether prepolymer.   
     
     
         19 . A part comprising the cured composition of  claim 16 . 
     
     
         20 . The part of  claim 19 , wherein the part is a part of an aerospace vehicle.