Nippon Shokubai Co., Ltd.

Keishi Tsuboi

Yoshio Irie

Shigeru Yamaguchi

Hiroshi Ito

Hideyuki Tahara

Masahito Takagi

Tokihiro Yokoi

A maleic acid-based copolymer is provided which has a weight-average molecular weight of 1,000 to 100,000, a calcium ion-capturability of 300 mgCaCO.sub.3 /g or higher calculated as calcium carbonate, and a clay-dispersibility of 1.2 or higher. Another maleic acid-based copolymer is also provided which has a level of adsorption to clay within the range of 20 to 90% and a calcium ion-stabilization degree constant of 4.0 or larger. These copolymers are obtainable by a process including the steps of: charging maleic acid and/or its salt (A) into a reaction vessel, in such a manner that the concentration of the (A) will be 35% by weight or higher; adding hydrogen peroxide into the vessel after the charging step, in such a manner that the amount of hydrogen peroxide is within the range of 3 to 20% by weight of the (A); and adding a water-soluble ethylenically unsaturated monomer (B) into the vessel after the charging step and within 30 to 500 minutes after initiation of a reaction, in such a manner that the ratio (A)/(B) is within the range of 95/5 to 5/95 in mol ratio, wherein the adding of the monomer (B) is completed 10 to 300 minutes later than completion of the step of adding hydrogen peroxide. The copolymers are used for detergent compositions, inorganic pigment-dispersing agents, water-treating agents and fiber-treating agents.

Maleic acid based copolymer, and its production process and use

Maleic acid based copolymer and its production process and use

A method of drying a viscous solution containing a (meth)acrylic acid-based polymer or copolymer containing (meth)acrylic acid and/or a salt thereof as a monomer unit, the degree of neutralization of the acid group contained in the polymer being not more than 50 mol %, wherein the method comprises subjecting the solution to, or passing the solution through, a drying zone, in the form of a line, so that the solvent in the solution is removed.

Drying process of viscous solution containing (meth)acrylic acid-based

The invention provides biodegradable crosslinked polymers, which have a chelating effect and a dispersing effect to disperse an oily substance and an inorganic substance hardly soluble in water and are excellent in dispersion into water. The crosslinked polymers comprise; an ingredient of molecular weight 5,000 or less in 50% by weight, a bond having at least one of a group (II) represented by the chemical formula --CO--O-- and a group (III) represented by the chemical formula --CO--NH-- as a composition unit between main chains having a water-soluble oligomer structure having the functional group (I) represented by the general formula --COOM (here, M denotes anyone of a hydrogen atom, monovalent metal, divalent metal, trivalent metal, an ammonium group and organic amine group.), and showing a viscosity of 1,000 cP or less at 20.degree. C. by a 20% by weight aqueous solution of the crosslinked polymer.

Biodegradable hydrophilic crosslinked polymer, process for producing it,

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Akashi, Japan

Keishi Tsuboi