Loading patent…
AssigneesNitto Chemical Industry Co., Ltd., Mitsubishi Rayon Co., Ltd.
InventorsNorimasa Yoshida, Yasuo Ogawa, Ryoji Handa, Susumu Seki, Jun Hosoda, Nobuo Kurashige, Akihisa Furuno
Estimating the term…
In the production of a dried acrylamide polymer by polymerizing, in an aqueous medium, acrylamide alone or a monomer mixture comprising 50 mole % or more of acrylamide and at least one monomer copolymerizable therewith with a radical initiator, and then drying the resulting hydrous acrylamide polymer, the allowing of at least one of the following compounds [I], [II] and [III] to be present in the drying step or a step prior thereto enables the dried acrylamide polymer having a high molecular weight and a good dissolvability in water to be obtained: [I] a non-polymerizable compound having in its molecule at least one group represented by the formula, ##STR1## wherein R.sub.1 is H or an alkyl group having up to 4 carbon atoms, [II] a compound represented by the formula, R.sub.2 --S--C.sub.n H.sub.2n X wherein n is an integer of 1 to 8, R.sub.2 is an alkyl group, an aryl group or --C.sub.n H.sub.2n X, in which X is --OH, --COOH (or its salt), --CN or --CONH.sub.2, and [III] a compound represented by the formula, ##STR2## wherein R.sub.3, R.sub.4 and R.sub.5 are H, alkali metals or alkyl or aryl groups.
A method for preparing a dried high molecular weight acrylamide polymer, which comprises polymerizing acrylamide alone or a monomer mixture consisting of 50 mole % or more of acrylamide and at least one monomer copolymerizable therewith with a radical initiator in an aqueous medium and drying the resulting hydrous acrylamide polymer, characterized by allowing at least one compound selected from the group consisting of the following compounds [I], [II], and [III] to be present in the drying step or a step prior thereto:
Dependencies are inferred from the claim text.