| 摘要 |
PURPOSE:To obtain a matting agent not causing coagulation or precipitation in a coating liq. during production when the matting agent is incorporated into the top layer of a sensitive material, by specifying the particle size of particles of a water insoluble org. polymer made from a compd. having a specified dissociable group. CONSTITUTION:A matting agent made of a water insoluble org. polymer is incorporated into the top layer of a sensitive material in the form of particles of 0.5-20mum particle size. The polymer is made from a compd. having a dissociable group having <=4 PKa in water at 25 deg.C. The matting agent has such dissociable groups on the surfaces of the particles. Since an ordinary coating liq. is used at 5-7 pH, an intense ion dissociated layer is formed on the surface of the matting agent and high ionic repulsion is retained among the particles. Accordingly, the matting agent is stable and does not cause coagulation or precipitation even after storage over a long period. |
