Process for the preparation of water absorptive resin
AssigneeMitsubishi Petrochemical Co., Ltd.
InventorsShuhei Yada, Takeshi Shibano, Kiichi Itoh, Kenji Yoshinaga
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Abstract
A process for the preparation of water absorptive resins which comprises supplying a solution containing at least 20% by weight of a water soluble ethylenically unsaturated monomer as a main component to a polymerization vessel accommodating a vapor phase comprising steam or a mixture of steam with at least one gas substantially inert with respect to polymerization, and polymerizing the monomer in the vapor phase under the relative humidity conditions in the vapor phase of 30% or more.
Claims5
A process for the preparation of water absorptive resins which comprises supplying a solution containing as a main component 45 to 80% by weight of a water soluble monomer selected from the group consisting of a partially neutralized sodium acrylate in which 20 to below 95% of the carboxyl groups are neutralized to its sodium salt and a partially neutralized potassium acrylate in which 40% or more of the carboxyl groups are neutralized to its potassium salt to a polymerization vessel accommodating a vapor phase comprising steam or a mixture of steam with at lest one gas substantially inert with respect to polymerization, and polymerizing the monomer with the use of a redox initiator or with irradiation of ultraviolet rays and/or high-energy radiations in the vapor phase under the relative humidity conditions in said vapor phase of 30% or more.
Dependencies are inferred from the claim text.