Binders containing nanoparticles

Abstract

The present invention relates to aqueous binder dispersions based on silane-modified polymeric binders and inorganic nanoparticles, a process for the preparation thereof and the use thereof for the production of high quality coatings, in particular clear lacquers.

1 . An aqueous formulation comprising
 B) a silane-modified copolymer;   B) optionally surface-modified inorganic particles having an average particle size (z-mean), as determined by means of dynamic light scattering in dispersion, of less than 200 nm; and   C) water.   
     
     
         2 . The aqueous formulation of  claim 1 , wherein said silane-modified copolymer A) comprises groups of general formula (1)
   —Si(R 1 O) 2 R 2   (1)   wherein   R 1  is a C 2 - to C 8 -alkyl radical; and   R 2  is (R 1 O) or a C 1 - to C 5 -alkyl radical.   
     
     
         3 . The aqueous formulation of  claim 1 , wherein said silane-modified copolymer A) is a copolymer which is built up from
 I) a hydroxy-functional hydrophobic polymer containing as builder monomers
 Ia) (meth)acrylic acid esters having C 1 - to C 18 -hydrocarbon radicals in the alcohol part and/or vinylaromatics and/or vinyl esters; 
 Ib) hydroxy-functional monomers; and 
 IS1) silane-functional monomers capable of polymerization; and 
   II) a hydroxy-functional hydrophilic polymer containing as builder components
 IIa) (meth)acrylic acid esters having C 1 - to C 18 -hydrocarbon radicals in the alcohol part and/or vinylaromatics and/or vinyl esters; 
 IIb) hydroxy-functional monomers; and 
 IIc) acid-functional monomers. 
   
     
     
         4 . The aqueous formulation of  claim 1 , wherein said silane-modified copolymer A) is a copolymer which is built up from
 I) a hydroxy-functional hydrophobic polymer containing as builder monomers
 Ia) (meth)acrylic acid esters having C 1 - to C 18 -hydrocarbon radicals in the alcohol part and/or vinylaromatics and/or vinyl esters; and 
 Ib) hydroxy-functional monomers; and 
   II) a hydroxy-functional hydrophilic polymer containing as builder components
 IIa) (meth)acrylic acid esters having C 1 - to C 18 -hydrocarbon radicals in the alcohol part and/or vinylaromatics and/or vinyl esters; 
 IIb) hydroxy-functional monomers; 
 IIe) acid-functional monomers; and 
 IIS1) silane-functional monomers capable of polymerization. 
   
     
     
         5 . The aqueous formulation of  claim 3 , wherein said silane-functional monomer IS1), which is capable of polymerization, is a compound of the general formula (2)
   (R 1 O) 2 R 2 Si—(CH═CH 2 )  (2)   
       wherein
 R 1  is a C 2 - to C 8 -alkyl radical; and 
 R 2  is (R 1 O) or a C 1 - to C 5 -alkyl radical; 
 
       and/or a compound of the general formula (3)
   (R 1 O) 2 R 2 Si(CH 2 ) m —O(CO)—(CR 3 ═CH 2 )  (3) 
 
       wherein
 R 1  is a C 2 - to C 8 -alkyl radical; 
 R 2  is (R 1 O) or a C 1 - to C 5 -alkyl radical; 
 R 3  is H or CH 3 ; and 
 m is 1 to 4. 
 
     
     
         6 . The aqueous formulation of  claim 4 , wherein said silane-functional monomer IIS1), which is capable of polymerization, is a compound of the general formula (2)
   (R 1 O) 2 R 2 Si—(CH═CH 2 )  (2)   
       wherein
 R 1  is a C 2 - to C 8 -alkyl radical; and 
 R 2  is (R 1 O)) or a C 3 - to C 5 -alkyl radical; 
 
       and/or a compound of the general formula (3)
   (R 1 O) 2 R 2 Si(CH 2 ) m —O(CO)—(CR 3 ═CH 2 )  (3) 
 
       wherein
 R 1  is a C 2 - to C 8 -alkyl radical; 
 R 2  is (R 1 O) or a C 1 - to C 5 -alkyl radical; 
 R 3  is H or CH 3 ; and 
 m is 1 to 4. 
 
     
     
         7 . The aqueous formulation of  claim 3 , wherein said silane-functional monomer IS1), which are capable of polymerization, is selected from the group consisting of vinyltriethoxysilane, vinyltrisisopropoxysilane, vinyl-tris-(2-methoxyethoxy)silane, vinylmethyldiethoxysilane, vinylmethyldiisopropoxysilane, vinylethyldiethoxysilane, 3-(triethoxysilyl)-propyl methacrylate or 3-(tris-isopropoxysilyl)-propyl methacrylate, vinylphenyldiethoxysilane, vinylphenylmethylethoxysilane, and vinyltri-t-butoxysilane. 
     
     
         8 . The aqueous formulation of  claim 4 , wherein said silane-functional monomers IIS1), which are capable of polymerization, is selected from the group consisting of vinyltriethoxysilane, vinyltrisisopropoxysilane, vinyl-tris-(2-methoxyethoxy)silane, vinylmethyldiethoxysilane, vinylmethyldiisopropoxysilane, vinylethyldiethoxysilane, 3-(triethoxysilyl)-propyl methacrylate or 3-(tris-isopropoxysilyl)-propyl methacrylate, vinylphenyldiethoxysilane, vinylphenylmethylethoxysilane, and vinyltri-t-butoxysilane. 
     
     
         9 . The aqueous formulation of  claim 1 , wherein said silane functional copolymer A) is a copolymer which is built up from
 I) a hydroxy-functional hydrophobic polymer containing as builder monomers
 Ia) (meth)acrylic acid esters having C 1 - to C 18 -hydrocarbon radicals in the alcohol part and/or vinylaromatics and/or vinyl esters; 
 Ib) hydroxy-functional monomers; and 
   II) a hydroxy-functional hydrophilic polymer containing as builder components
 IIa) (meth)acrylic acid esters having C 1 - to C 18 -hydrocarbon radicals in the alcohol part and/or vinylaromatics and/or vinyl esters; 
 IIb) hydroxy-functional monomers; 
 IIc) acid-functional monomers; and 
 IIS2) monomers which contain at least one epoxide function in addition to silane groups. 
   
     
     
         10 . The aqueous formulation of  claim 9 , wherein said monomers IIS2) are selected from the group consisting of γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl-tris-isopropoxysilane, γ-glycidoxypropyl-diethoxy-methylsilane, β-(3,4-epoxycyclohexyl)-triethoxysilane, and β-(3,4-epoxycyclohexyl)-tris-isopropoxysilane. 
     
     
         11 . The aqueous formulation of  claim 1 , wherein said inorganic particles B) are selected from the group consisting of inorganic oxides, mixed oxides, carbides, borides, and nitrides of elements of main group II to IV and/or elements of subgroup I to VIII of the periodic table, including the lanthanides. 
     
     
         12 . The aqueous formulation of  claim 1 , wherein said inorganic particles B) are inorganic nanoparticles in a colloidally disperse form in organic solvents or in water. 
     
     
         13 . The aqueous formulation of  claim 1 , wherein said inorganic particles B) are inorganic particles in the form of aqueous formulations. 
     
     
         14 . The aqueous formulation of  claim 1 , wherein said inorganic particles B) are surface-modified inorganic nanoparticles. 
     
     
         15 . An aqueous coating composition comprising the aqueous formulation of  claim 1  and at least one crosslinking agent D). 
     
     
         16 . An aqueous two-component coating composition comprising the aqueous formulation of  claim 1  and a polyisocyanate. 
     
     
         17 . A clear lacquer comprising the aqueous formulation of  claim 1 .