Flexible coating composition

Abstract

The present disclosure describes polymers and improved resin systems having flexibility, low water uptake, good adhesion, chemical resistance, and/or weatherability at extreme negative temperatures, such as temperatures down to about −40° C. or below and even temperatures down to about −60° C. The systems herein, in approaches, include a polymer or resin system for an epoxy component of an epoxy/amine system including an epoxy and/or acetoacetoxy functionalized flexible block copolymer that has a base hydrophobic polyol block or core, optional flexible monomeric blocks, and epoxy, acetoacetoxy, or both functional endcaps.

What is claimed is: 
     
         1 . A flexible block copolymer for use in an epoxy component of a two-part, epoxy-amine system, the flexible block copolymer comprising:
 a hydrophobic polyol block;   functional endcaps provided by epoxy groups, acetoacetate groups, or both, the endcaps having a functionality greater than 1;   optional isocyanate-functional extension groups; and   when the hydrophobic polyol block includes epoxy or fatty acid derived polyol groups, then the flexible copolymer further includes one or more cyclic ester-derived blocks between the hydrophobic polyol block and the functional endcaps, wherein each cyclic ester-derived block includes the residue of at least 3 or more repeating cyclic ester groups.   
     
     
         2 . The flexible polymer according to  claim 1 , wherein the hydrophobic polyol block includes a C20 to a C60 dimer or trimer fatty acid diol and wherein the one or more cyclic ester-derived blocks includes the residue of at least 3 or more repeating lactone groups. 
     
     
         3 . The flexible polymer according to  claim 1 , where the hydrophobic polyol block includes a polyalkyleneglycol diol having a number average molecular weight of about 500 to about 2000 g/mol. 
     
     
         4 . The flexible polymer according to  claim 3 , wherein the polyalkylene glycol diol is a polyethylene glycol diol or a polypropylene glycol diol. 
     
     
         5 . The flexible polymer according to  claim 1 , wherein the hydrophobic polyol block is derived from a diester of a digycidyl ether. 
     
     
         6 . The flexible polymer according to  claim 1 , wherein the hydrophobic polyol block is derived from glycidyl ethers of (cyclo)aliphatic or aromatic hydroxy compounds or derived from glycidyl ethers based on polyhydric alcohols or phenols. 
     
     
         7 . The flexible polymer according to  claim 1 , wherein the hydrophobic polyol block is derived from a diester of a digycidyl ester. 
     
     
         8 . The flexible polymer according to  claim 1 , wherein the hydrophobic polyol block is derived from polyglycidyl esters of polycarboxylic acids. 
     
     
         9 . The flexible polymer according to  claim 1 , further comprising the isocyanate-functional extension groups selected from 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 1,6-hexane diisocyanate, methylene bis (4-cyclohexylisocyanate), and combinations thereof. 
     
     
         10 . The flexible polymer according to  claim 1 , wherein the functional endcaps includes acetoacetate groups. 
     
     
         11 . The flexible polymer according to  claim 10 , wherein the acetoacetate groups are derived from C1 to C6 acetoacetate. 
     
     
         12 . A flexible block copolymer for use in an epoxy component of a two-part, epoxy-amine system, the flexible block copolymer comprising the reaction product of (i) a hydrophobic polyol selected from a C20 to C60 dimer or trimer fatty acid, diesters of a digycidyl ether, diesters of a digycidyl ester, and combinations thereof; (ii) optional isocyanate-functional extension groups, and (iii) one or more C4 to C9 cyclic esters; the reaction product is functionally end capped with epoxy groups, acetoacetate groups, or both, the endcaps having a functionality greater than 1; and wherein the one or more C4 to C9 cyclic esters form a cyclic ester-derived block of the flexible block copolymer including at least 3 or more repeating cyclic ester-derived groups. 
     
     
         13 . The flexible block copolymer according to  claim 12 , wherein the hydrophobic polyol is the C20 to a C60 dimer or trimer fatty acid and wherein the cyclic ester-derived block includes the residue of at least 3 or more repeating caprolactone-derived groups. 
     
     
         14 . The flexible block copolymer according to  claim 12 , wherein the hydrophobic polyol is derived from a diester of a digycidyl ether. 
     
     
         15 . The flexible block copolymer according to  claim 12 , wherein the hydrophobic polyol block is derived from glycidyl ethers of (cyclo)aliphatic or aromatic hydroxy compounds or derived from glycidyl ethers based on polyhydric alcohols or phenols. 
     
     
         16 . The flexible block copolymer according to  claim 12 , wherein the hydrophobic polyol is derived from a diester of a digycidyl ester. 
     
     
         17 . The flexible polymer according to  claim 12 , wherein the hydrophobic polyol block is derived from polyglycidyl esters of polycarboxylic acids. 
     
     
         18 . The flexible block copolymer according to  claim 12 , further comprising the isocyanate-functional extension groups selected from 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 1,6-hexane diisocyanate, methylene bis (4-cyclohexylisocyanate), and combinations thereof. 
     
     
         19 . The flexible block copolymer according to  claim 12 , wherein the functional endcaps includes the acetoacetate groups derived from C1 to C6 acetoacetate. 
     
     
         20 . A coating composition including the flexible block copolymer of  claim 12 .