Stain-proofing agent for preventing adherence of stain

Abstract

A paint composition being capable of forming a coating film which is remarkably excellent in stain-proofing property whereby neither stains in the air nor stains marked due to rain water adhere to or are deposited on the coating film surface and a stain-proofing agent for adding to the composition are provided. The paint composition comprises a stain-proofing agent comprising an organometallic compound represented by X b M(OR 1 ) a R 2 c , its oligomer or cooligomer comprising two or more of the organometallic compounds; a resin for paints; and a curing agent and/or a curing catalyst, provided that a stain-proofing agent comprising a compound represented by the formula (2): is excluded.

1 . A stain-proofing agent comprising, an organometallic compound represented by the formula (1): 
       X b M(OR 1 ) a R 2   c   (1) wherein    a is 0 or an integer of 1 to 6, b is 0 or an integer of 1 to 5, c is 0 or an integer of 1 to 6, provided that a+b+c≧3, a and c are not zero at the same time,    X are the same or different, and each is hydrogen atom or a monovalent organic group which has 1 to 5,000 carbon atoms and may contain oxygen atom, nitrogen atom, fluorine atom and/or chlorine atom,    M is a metal atom having at least three valences,    R 1  are the same or different, and each is hydrogen atom, a siloxane residue or a monovalent organic group which has 1 to 1,000 carbon atoms and may contain oxygen atom, nitrogen atom, fluorine atom and/or chlorine atom,    R 2  are the same or different, and each is an organic group which has 1 to 20 carbon atoms, has a chelating ability and may contain oxygen atom, nitrogen atom, fluorine atom and/or chlorine atom;    an oligomer thereof; or    a cooligomer comprising two or more of said organometallic compounds;    provided that said stain-proofing agent excludes a stain-proofing agent comprising a compound represented by the formula (2):                          wherein n is an integer of 1 to 20, all of R 15  are different or at least two of R 15  are the same, each is a monovalent organic group which has 1 to 1,000 carbon atoms and may contain oxygen atom, nitrogen atom and/or silicon atom and a part or the whole of hydrogen atoms of said organic group may be substituted by fluorine atom or fluorine atom and chlorine atom.    
     
     
         2 . The stain-proofing agent of    claim 1   , wherein in the formula (1), the metal atom M is aluminium atom, titanium atom, boron atom, zirconium atom or silicon atom.  
     
     
         3 . The stain-proofing agent of    claim 1    or    2   , wherein at least one of R 1  and R 2  of the organometallic compound represented by the formula (1), its oligomer or cooligomer comprising two or more of the organometallic compounds has fluorine atom.  
     
     
         4 . The stain-proofing agent of any of    claims 1    to    3   , wherein a content of fluorine atom in the organometallic compound represented by the formula (1), its oligomer or cooligomer comprising two or more of the organometallic compounds is at least 5% by weight.  
     
     
         5 . The stain-proofing agent of    claim 3    or    4   , wherein the oligomer or cooligomer is an oligomer of the organometallic compound of the formula (1), in which a is 4, b and c are 0 and M is Si, or a cooligomer comprising two or more of the organometallic compounds, respectively and a degree of polymerization is more than 20 and not more than 100.  
     
     
         6 . The stain-proofing agent of any of    claims 1    to    4   , wherein in the organometallic compound represented by the formula (1), its oligomer or cooligomer comprising two or more of the organometallic compounds, a molar ratio of X to R 1 +R 2  is not more than 0.2, namely b/(a+c)≦0.2.  
     
     
         7 . A composition for paints which comprises (A) the stain-proofing agent of any of    claims 1    to    6   , (B) a resin for paints and (C) a curing agent and/or a curing catalyst.  
     
     
         8 . The composition for paints of    claim 7   , wherein the resin for paints is a fluoroolefin copolymer having hydroxyl group and/or carboxyl group, acrylic polyol resin, acrylic silicon resin, inorganic material or homopolymer or copolymer of vinylidene fluoride having no functional group, which is solvent-soluble.