Blocked polyisocyanate composition, one-component coating composition, coating film, and coated article

Abstract

The present invention provides a blocked polyisocyanate composition comprising a blocked polyisocyanate formed through blocking at least a part of isocyanate groups possessed by a polyisocyanate derived from one or two or more diisocyanates selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate with an active methylene-based compound comprising a malonic acid diester, wherein a specific molar ratio calculated from contents (mol %) of isocyanurate groups, iminooxadiazinedione groups, uretdione groups, and allophanate groups is 0.05 or more and 0.60 or less.

1 . A blocked polyisocyanate composition comprising a blocked polyisocyanate formed through blocking at least a part of isocyanate groups possessed by a polyisocyanate derived from one or two or more diisocyanates selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate with an active methylene-based compound comprising a malonic acid diester, wherein
 a specific molar ratio represented by formula (1) is 0.05 or more and 0.60 or less:
   specific molar ratio=( B+C+D )/( A+B+C+D )  (1)
 
   
       wherein A represents a content (mol %) of isocyanurate groups represented by formula (I); B represents a content (mol %) of iminooxadiazinedione groups represented by formula (II); C represents a content (mol %) of uretdione groups represented by formula (III); and D represents a content (mol %) of allophanate groups represented by formula (IV). 
       
         
           
           
               
               
           
         
       
     
     
         2 . The blocked polyisocyanate composition according to  claim 1 , wherein the blocked polyisocyanate composition comprises a component having a number average molecular weight of 1500 or less in a content of 55 mass % or more and 80 mass % or less based on a total amount of the blocked polyisocyanate composition. 
     
     
         3 . The blocked polyisocyanate composition according to  claim 1 , wherein the malonic acid diester compound comprises diethyl malonate. 
     
     
         4 . The blocked polyisocyanate composition according to  claim 1 , wherein the malonic acid diester compound comprises diisopropyl malonate. 
     
     
         5 . The blocked polyisocyanate composition according to  claim 1 , wherein the active methylene-based compound further comprises a β-ketoester compound. 
     
     
         6 . The blocked polyisocyanate composition according to  claim 5 , wherein the β-ketoester compound comprises ethyl acetoacetate. 
     
     
         7 . The blocked polyisocyanate composition according to  claim 1 , further comprising a monohydric alcohol. 
     
     
         8 . The blocked polyisocyanate composition according to  claim 1 , wherein the diisocyanates comprise hexamethylene diisocyanate. 
     
     
         9 . A one-component coating composition comprising the blocked polyisocyanate composition according to  claim 1 , and a polyvalent active hydrogen compound. 
     
     
         10 . A coating film formed of the one-component coating composition according to  claim 9 . 
     
     
         11 . A coated article comprising the coating film according to  claim 10 . 
     
     
         12 . A method for producing a composite coating film, the method comprising coating with a first coating material solution comprising the one-component coating composition according to  claim 9  to form a first coating film; and coating the first coating film with a second coating material solution to form a second coating film. 
     
     
         13 . A composite coating film comprising a first coating film formed of the one-component coating composition according to  claim 9 , and a second coating film on the first coating film.