Abstract: A process for preparing hollow polymer particles which comprises a seed-forming step for polymerizing a monomer mixture of an acid monomer having a carboxylic acid group and a non-ionic hydrophilic monomer in the presence of a polymerization initiator; a core-forming step for preparing a core, which can be swollen with an alkali, by polymerizing the monomer mixture of an acid monomer having a carboxylic acid group, a non-ionic hydrophilic monomer and a cross-linking agent to the seed latex; a shell-forming step in which a hydrophobic shell is formed on the hydrophilic core; and an alkali-swelling step.

Abstract: The processes for producing highly water absorptive resins of the present invention comprise the following steps: (A) suspending an aqueous solution of partially neutralized alkali metal acrylate and optionally partially neutralized acrylamido alkane sulfonate in a hydrocarbon solvent containing a surfactant having a HLB value of 3.apprxeq.6 or 8.apprxeq.

Abstract: A method for the production of a highly water absorptive resin comprises the steps of neutralizing acrylic acid with alkali metal hydroxide to form an alkali metal acrylate; mixing the alkali metal acrylate, methacrylic acid, a polymerization initiator, and a first crosslinking agent; suspending and dispersing the mixture in an aqueous medium to for an initial mixture; polymerizing the initial mixture to produce a polymerized intermediate, and separating the moisture from the polymerized intermediate by azeotropic distillation to reduce the water content to 15-35% by weight; adding a second crosslinking agent, said second crosslinking agent having two epoxy radicals; and mixing "Syloid" of silicate, to form a highly water absorptive resin.