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AssigneeNippon Shokubai Co., Ltd.
InventorsDaijo Tomihisa, Nobuyuki Harada, Akio Naka, Toshiaki Kuriyama, Yuuji Shimasaki, Hideyuki Nishibayashi
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The present invention provides a production process for a vinylpyrrolidone polymer which process prevents the polymerization reaction of N-vinylpyrrolidone from being hindered by by-products (as formed by nucleomethylation of N-vinylpyrrolidone) or γ-butyrolactone, and therefore enables to obtain a vinylpyrrolidone polymer that has a desired molecular weight and involves only a small amount of residual monomers, wherein the vinylpyrrolidone polymer can display excellent properties even if the vinylpyrrolidone polymer is, for example, crosslinked to convert it into a water-absorbent resin. The production process for a vinylpyrrolidone polymer comprises the step of polymerizing a polymerizable monomer component or components which include N-vinylpyrrolidone, wherein: the N-vinylpyrrolidone as used is N-vinylpyrrolidone having a γ-butyrolactone content of not more than 500 ppm; and/or the N-vinylpyrrolidone as used is N-vinylpyrrolidone obtained without using acetylene as a raw material.
A production process for a vinylpyrrolidone polymer, comprising the step of polymerizing a polymerizable monomer component or components which include N-vinylpyrrolidone, wherein the N-vinylpyrrolidone as used is N-vinylpyrrolidone having a γ-butyrolactone content of not more than 500 ppm.
A production process for a vinylpyrrolidone polymer, comprising the step of polymerizing a polymerizable monomer component or components which include N-vinylpyrrolidone, wherein the N-vinylpyrrolidone as used is N-vinylpyrrolidone obtained without using acetylene as a raw material.
Dependencies are inferred from the claim text.