PURPOSE: To easily obtain the clathrate water which can produce the gypsum molding having high strength by crosslinking a copolymer contg. alkyl ester of (meth)acrylic acid and (meth)acrylic acid or (meth)acrylamide by a specific treatment.
CONSTITUTION: The desired clathrate water is obtd. by using the water absorptive polymer obtd. by dissolving the acryl copolymer contg. (a) 40 to 95wt.% monomer of the alkyl ester of acrylic acid or alkyl ester of methacrylic acid and of ≥8C alkyl group, (b) 5 to 40wt.% monomer of at least one kind of the deriv. contg. one kind selected from a carboxyl group, amino group, quaternary ammonium salt group hydroxyl group and selected from acrylic acid, methacrylate acid, acrylamide, and methacrylamide, and (c) 0 to 40wt.% unsatd. monomer copolymerizable with the abovementioned (a), (b) as the constituting elements into aliphat. hydrocarbon, dispersing the aq. soln. of the acrylic acid and the alkaline metal salt thereof, subjecting the soln. to a reverse suspension polymn., and further crosslinking the polymer with a crosslinking agent, then drying the polymer.
KAMIBAYASHI TAIJI
MEGATA HIDEYUKI
KATAOKA HIROYUKI
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