Acrylic-urethane composite resin particles

A method for producing acrylic urethane composite resin particles comprising an acrylic urethane graft resin (I) and a graft acrylic resin (II), the method comprising the following step:

• synthesizing the acrylic urethane graft resin (I) in the presence of the graft acrylic resin (II) in an aqueous medium, the graft acrylic resin (II) being a hydrophobic-chain- and hydrophilic-chain-containing resin having a weight average molecular weight of 5000 or more,
• the acrylic urethane graft resin (I) comprising an acrylic resin component and a urethane resin component,
• the acrylic resin portion of the acrylic urethane graft resin (I) being synthesized using, as constituent monomer components, 0.1 to 30 mass % of a polymerizable unsaturated monomer (1) containing a group having active hydrogen atom(s) reactive with an isocyanate group and 70 to 99.9 mass % of other polymerizable unsaturated monomer(s) (2),
• wherein the graft acrylic resin (II) has a structure in which a hydrophobic chain component (A) and a hydrophilic chain component (B) are grafted together and the difference in solubility parameter between the hydrophobic chain component (A) and hydrophilic chain component (B) is at least 0.5.