Coating composition, coating film, method of manufacturing coating film, and optical recording medium

Abstract

A coating composition containing a solvent and a coating agent having an ionizing radiation-curable compound as a principal component thereof, wherein under the following condition for the concentration a (wt %) of the coating agent in the coating composition 0<a≦60, the concentration a of the coating agent and the surface tension b (dyne/cm) of the coating composition satisfy the following relationship b≦(−a/15)+26, is applied onto a surface of a protective film 11 and curing is carried out to form a hard coating layer 12 . Even in the case that projections or foreign bodies are present on the surface of the protective film 11 , the hard coating layer 12 can conceal these and hence can have high surface smoothness.

1 - 11 . (canceled) 
   
   
       12 . An optical recording medium having a coating film comprising:
 a resin film; and   a coating layer obtained by applying a coating composition onto one surface of said resin film and performing curing,   said coating composition contains a coating agent having an ionizing radiation-curable compound as a principal component thereof, and   under the following condition for the concentration a (wt %) of said coating agent in the coating composition
   0<a≦60, 
   the concentration a of said coating agent and the surface tension b (dyne/cm) of the coating composition satisfy the following relationship
     b ≦(− a/ 15)+26. 
   
   
   
       13 . The optical recording medium according to  claim 12 , wherein projections are present on the surface of said resin film on which said coating layer is formed, and the maximum height of said projections is h (μm), the thickness d (μm) of said coating layer satisfies the following condition
     d≧h +1.   
   
   
       14 . The optical recording medium according to  claim 12 , wherein an adhesive layer is provided on the surface of said resin film on which said coating layer is not formed. 
   
   
       15 . The optical recording medium according to  claim 12 , wherein said resin film comprises a material having a polymethyl methacrylate resin, a polycarbonate resin or a cycloolefin resin as a principal component thereof. 
   
   
       16 . An optical recording medium having a coating film obtained using a method,
 comprising forming a coating layer by applying a coating composition that has been obtained by adjusting the concentration of a coating agent therein having an ionizing radiation-curable compound as a principal component thereof onto a surface of a resin film and performing curing, and   said coating composition is prepared such that under the following condition for the concentration a (wt %) of said coating agent in said coating composition
   0<a≦60, 
   the concentration a of said coating agent and the surface tension b (dyne/cm) of said coating composition satisfy the following relationship
     b ≦(− a/ 15)+26. 
   
   
   
       17 . The optical recording medium according to  claim 16 , wherein said coating layer is formed such that in the case that projections having a maximum height of h (μm) are present on the surface of said resin film on which said coating layer is formed, the thickness d (μm) of said coating layer satisfies the following condition
     d≧h+ 1.