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AssigneeSeitetsu Kagaku Co., Ltd.
InventorsShigeji Obayashi, Morio Nakamura, Koichi Fujiki, Takushi Yamamoto
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An alkali metal acrylate polymer obtained by suspending an aqueous solution of acrylic acid and an alkali metal acrylate in an alicyclic or aliphatic hydrocarbon solvent containing a surfactant having an HLB value of 8-12 and subjecting the suspension to inverse suspension polymerization in the presence of a water-soluble radical polymerization initiator has a much higher water-absorbency and particularly salt solution-absorbency than known ones. If said polymer is crosslinked with a crosslinking agent, its stability in the fluid-absorbed state for a long period of time is improved and the absorption rate when absorbing water is also improved.
A process for producing an alkali acrylate polymer having excellent salt solution-absorbency, characterized by suspending an aqueous solution of acrylic acid and an alkali metal acrylate or ammonium acrylate, wherein the monomer concentration is at least 40% by weight, the mole ratio of the acrylic acid to said acrylate is 50/50 to 2/98, in an alicyclic or aliphatic hydrocarbon solvent containing a surfactant having an HLB value of 8-12 and subjecting it to inverse suspension polymerization in the presence of a water-soluble radical polymerization initiator.
A process for producing an alkali acrylate polymer having excellent salt solution-absorbency, characterized by suspending an aqueous solution of acrylic acid and an alkali metal acrylate or ammonium acrylate, wherein the monomer concentration is at least 40% by weight, the mole ratio of the acrylic acid to said acrylate is 50/50 to 2/98, in an alicyclic or aliphatic hydrocarbon solvent containing a surfactant having an HLB value of 8-12, subjecting it to inverse suspension polymerization in the presence of a water-soluble radical polymerization initiator, thereafter adding a water-soluble diglycidyl ether, haloepoxy, or aldehyde cross-linking agent, subjecting the resulting mixture to crosslinking reaction.
Dependencies are inferred from the claim text.