Abstract: Provided is a polishing composition which exhibits favorable storage stability and polishes a polishing object poor in chemical reactivity at a high speed. The invention is a polishing composition which contains silica having an organic acid immobilized on a surface thereof, a dihydric alcohol having a molecular weight of less than 20,000 and a pH adjusting agent, the polishing composition having a pH of 6 or less.

Abstract: Provided is a process for efficiently producing heat-expandable microspheres having high solvent resistance. The process produces the heat-expandable microspheres composed of a shell of a thermoplastic resin and a blowing agent encapsulated therein and vaporizable by heating, and includes the steps of preparing an aqueous suspension by dispersing an oily mixture containing a polymerizable component, the blowing agent, and a polymerization initiator containing, as an essential component, a peroxide A having a theoretical active oxygen content of at least 7.8%, and polymerizing the polymerizable component in the oily mixture.