Composite particles, method for producing composite particles, and use thereof

Abstract

In a method for producing composite particles containing polymer particles and silica particles that adhere to the polymer particles, the composite particles are obtained by subjecting a polymerizable monomer to aqueous suspension polymerization in a presence of silica particles and a cellulose compound adsorbing onto the silica particles. The composite particles contain the polymer particles, the silica particles that adhere to surfaces of the polymer particles, and the water-soluble cellulose compound.

1 . A method for producing composite particles containing polymer particles and silica particles that adhere to the polymer particles, comprising a polymerization step of subjecting a polymerizable monomer to aqueous suspension polymerization in a presence of silica particles and a water-soluble cellulose compound adsorbing onto surfaces of the silica particles, so as to obtain the composite particles. 
     
     
         2 . The method for producing composite particles according to  claim 1 ,
 wherein at least one of hydroxypropyl cellulose and hydroxypropyl methylcellulose is used as the water-soluble cellulose compound.   
     
     
         3 . The method for producing composite particles according to  claim 1 , further comprising, before the polymerization step, an adsorption step of treating the silica particles with the water-soluble cellulose compound so as to adsorb the water-soluble cellulose compound onto the surfaces of the silica particles. 
     
     
         4 . The method for producing composite particles according to  claim 3 ,
 wherein, in the adsorption step, the water-soluble cellulose compound is adsorbed onto the surfaces of the silica particles by making the silica particles coexist with the water-soluble cellulose compound under a temperature condition where the water-soluble cellulose compound has a temperature of (T-15)° C. or more (where T represents a lower critical solution temperature (° C.) or a cloud point (° C.) of the water-soluble cellulose compound).   
     
     
         5 . The method for producing composite particles according to  claim 1 ,
 wherein an amount of the silica particles is from 0.022 to 0.15 g/m 2  per unit surface area of the composite particles.   
     
     
         6 . Composite particles obtainable by the method for producing composite particles according to  claim 1 ,
 wherein at least part of surfaces of the polymer particles is covered by a layer of the silica particles.   
     
     
         7 . Composite particles comprising polymer particles, silica particles that adhere to surfaces of the polymer particles, and water-soluble cellulose compound. 
     
     
         8 . The composite particles according to  claim 7 ,
 wherein an adhesion amount of the silica particles to the surfaces of the polymer particles is from 0.010 to 0.10 g/m 2  per unit surface area of the composite particles.   
     
     
         9 . The composite particles according to  claim 7 ,
 wherein at least part of the surfaces of the polymer particles is covered by a layer of the silica particles.   
     
     
         10 . An external preparation comprising the composite particles according to  claim 7 . 
     
     
         11 . A coating agent comprising the composite particles according to  claim 7 . 
     
     
         12 . An optical film obtainable by applying the coating agent according to  claim 11  onto a base material. 
     
     
         13 . A resin composition comprising: the composite particles according to  claim 7 ; and a base resin. 
     
     
         14 . A molded product obtainable by molding the resin composition according to  claim 13 .