Epoxy siloxane coating compositions

Abstract

Epoxy-polysiloxane based coating and flooring compositions exhibiting improved flexibility, and excellent weatherability and corrosion resistance after curing are described. The epoxy-polysiloxane polymer coating composition may be prepared by combining a polysiloxane, an epoxide resin material and a cure system including a blend of compounds selected from a dialkoxy functional aminosilane, a trialkoxy functional aminosilane, and an amino functional polysiloxane resin, where the blend has an average alkoxy functionality value of 2.0 to 2.8

1 . An epoxy-polysiloxane polymer coating composition comprising:
 water;   a polysiloxane having the formula   
       
         
           
           
               
               
           
         
         where,
 (a) each R 1  is independently selected from a hydroxy group, an alkyl group having up to six carbon atoms, an aryl group having up to six carbon atoms, or alkoxy group having up to six carbon atoms, 
 (b) each R 2  is independently selected from a hydrogen, an alkyl group having up to six carbon atoms, or an aryl group having up to six carbon atoms, and 
 (c) n is selected so that the molecular weight for the polysiloxane is in the range of 400 to 10,000; 
 
         a non-aromatic epoxide resin having more than one 1,2-epoxide group per molecule with an epoxide equivalent weight of 100 to 5,000; 
         a flexible epoxy resin based on the glycidyl ether of castor oil having an epoxide equivalent weight of 200 to 1,000; and 
         a cure system blend. 
       
     
     
         2 . The coating composition of  claim 1 , wherein the cure system blend comprises at least one trialkoxy functional aminosilane and at least one amino functional polysiloxane resin. 
     
     
         3 . The coating composition of  claim 2 , wherein the cure system blend has an alkoxy content of 10% by weight to 25% by weight. 
     
     
         4 . The coating composition of  claim 2 , wherein the cure system blend has an average alkoxy functionality value of 2.2 to 2.8. 
     
     
         5 . The coating composition of  claim 2 , wherein the at least one trialkoxy functional aminosilane has a general formula 
       
         
           
           
               
               
           
         
       
       and;
 the at least one amino functional polysiloxane resin has a general formula 
 
       
         
           
           
               
               
           
         
         where,
 (a) R 5  is a difunctional organic radical selected from an aryl, an alkyl, a dialkylaryl, an alkoxyalkyl, an alkylaminoalkyl, or a cycloalkyl radical, 
 (b) each R 6  is independently selected from an alkyl, a hydroxyalkyl, an alkoxyalkyl, or a hydroxyalkoxyalkyl group containing less than six carbon atoms, 
 (c) each R 8  is a difunctional organic radical independently selected from an aryl, alkyl, dialkylaryl, alkoxyalkyl, alkylaminoalkyl, or cycloalkyl radical, 
 (d) each R 9  is independently selected from an aryl, phenyl, (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, or —OSi(R 10 ) 2 R 8 NH 2  group, wherein R 8  of the formula —OSi(R 10 ) 2 R 8 NH 2  is a difunctional organic radical independently selected from an aryl, alkyl, dialkylaryl, alkoxyalkyl, alkylaminoalkyl, or cycloalkyl radical, and each R 10  of the formula —OSi(R 10 ) 2 R 8 NH 2  is independently an aryl, phenyl, (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, and 
 (e) m is selected so that the blend has an amine equivalent weight ranging from 112 to 250 g/NH. 
 
       
     
     
         6 . The coating composition of  claim 5 , wherein R 5  is a difunctional organic radical selected from (C 1 -C 6 )alkyl or (C 1 -C 6 )alkylamino(C 1 -C 6 )alkyl groups and each R 6  is independently a (C 1 -C 6 )alkyl group. 
     
     
         7 . The coating composition of  claim 2 , wherein the at least one trialkoxy functional aminosilane comprises aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminopropyltripropoxysilane, aminoneohexyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltriethoxysilane, N-phenylaminopropyl trimethoxysilane, trimethoxysilylpropyl diethylene triamine, 3-(3-aminophenoxy)propyl trimethoxysilane, aminoethyl aminomethyl phenyl trimethoxysilane, 2-aminoethyl-3-aminopropyl-tris-2-ethylhexoxysilane, N-aminohexyl aminopropyl trimethoxysilane, and/or trisaminopropyl trismethoxyethoxysilane. 
     
     
         8 . The coating composition of  claim 5 , wherein the at least one amino functional polysiloxane resin has a structure where R 9  includes greater than 70% of phenyl groups, less than 30% of (C 1 -C 4 )alkyl groups and less than 2.0% (C 1 -C 4 )alkoxy groups. 
     
     
         9 . The coating composition of  claim 8 , wherein R 9  includes less than 0.5% of (C 1 -C 4 )alkoxy groups. 
     
     
         10 . The coating composition of  claim 2 , wherein the at least one amino functional polysiloxane resin comprises an amino-functional phenyl methyl polysiloxane resin. 
     
     
         11 . The coating composition of  claim 10 , wherein the at least one amino functional polysiloxane resin has an amine equivalent weight of 240 to 280 g/NH. 
     
     
         12 . The coating composition of  claim 1 , wherein the cure system blend comprises 15% to 85% by weight of at least one trialkoxy functional aminosilane and 85% to 15% of at least one amino functional polysiloxane resin. 
     
     
         13 . The coating composition of  claim 1 , wherein the coating composition comprises:
 20% to 80% by weight of the polysiloxane;   20% to 80% by weight of the non-aromatic epoxy resin;   2% to 15% by weight of the flexible epoxy resin; and   5% to 40% by weight of the cure system blend.   
     
     
         14 . The coating compositions of  claim 2 , wherein the coating composition comprises a ratio of amine equivalents to epoxide equivalents ranging from 0.7:1.0 to 1.3:1.0. 
     
     
         15 . The coating composition of  claim 1 , wherein the non-aromatic epoxide resin comprises a cycloaliphatic epoxide resin comprising a hydrogenated cyclohexane dimethanol or diglycidyl ether of a hydrogenated Bisphenol A epoxide resin. 
     
     
         16 . The coating composition of  claim 1 , further comprising up to 15% of a cure accelerator comprising a zinc, manganese, zirconium, titanium, cobalt, iron, lead, and/or tin catalyst, each in the form of octanoates, neodecanoates, or naphthanates. 
     
     
         17 . The coating composition of  claim 1 , further comprising one or more corrosion inhibitor comprising zinc or phosphate based corrosion inhibitors or organic corrosion inhibitors. 
     
     
         18 . A coated substrate comprising at least one surface coated at least in part with a coating composition comprising:
 water;   a polysiloxane having the formula   
       
         
           
           
               
               
           
         
         where,
 (a) each R 1  is independently selected from a hydroxy group, an alkyl group having up to six carbon atoms, an aryl group having up to six carbon atoms, or alkoxy group having up to six carbon atoms, 
 (b) each R 2  is independently selected from a hydrogen, an alkyl group having up to six carbon atoms, or an aryl group having up to six carbon atoms, and 
 (c) n is selected so that the molecular weight for the polysiloxane is in the range of 400 to 10,000; 
 
         a non-aromatic epoxide resin having more than one 1,2-epoxide group per molecule with an epoxide equivalent weight of 100 to 5,000; 
         a flexible epoxy resin based on the glycidyl ether of castor oil having an epoxide equivalent weight of 200 to 1,000; and 
         a cure system blend. 
       
     
     
         19 . A method for -coating at least a portion of a substrate with a coating composition, the method comprising:
 adding a cure system blend to a resin component to form an epoxy-modified polysiloxane coating composition; and   applying the epoxy-modified polysiloxane coating composition to at least a portion of the substrate before the coating composition becomes fully cured,   wherein the resin component comprises:
 a polysiloxane having the formula: 
   
       
         
           
           
               
               
           
         
         
           where, 
           (a) each R 1  is independently selected from a hydroxy group, an alkyl group having up to six carbon atoms, an aryl group having up to six carbon atoms, or alkoxy group having up to six carbon atoms, 
           (b) each R 2  is independently selected from a hydrogen, an alkyl group having up to six carbon atoms, or an aryl group having up to six carbon atoms, and 
           (c) n is selected so that the molecular weight for the polysiloxane is in the range of 400 to 10,000, 
         
         a non-aromatic epoxide resin having more than one 1,2-epoxide group per molecule with an epoxide equivalent weight of 100 to 5,000, and 
         a flexible epoxy resin based on the glycidyl ether of castor oil having an epoxide equivalent weight of 200 to 1,000. 
       
     
     
         20 . The method of  claim 19 , wherein the cure system blend comprises:
 at least one trialkoxy functional aminosilane and at least one amino functional polysiloxane resin; and   optionally a cure accelerator comprising at least one metal catalyst,   wherein the blend has an alkoxy content of 10% by weight to 25% by weight.