Nippon Shokubai Co., Ltd.

Junichi Chosa

Norihiro Wakao

Akihiko Kanzaki

Tomoyuki Kuwamoto

Tatsuhito Matsuda

Takashi Tomita

Jiro Iriguchi

Malcolm Andrew Kelland

An object of the present invention is to provide an aqueous poly(meth)acrylic acid (salt) solution having high dispersibility of inorganic substances and demonstrating dispersibility having sufficient stability over time, and a process for preparing the same. The present invention relates to an aqueous poly(meth)acrylic acid (salt) solution comprising a poly(meth)acrylic acid (salt) having a weight average molecular weight of 1000 to 10000 polymerized in the presence of a phosphorus compound containing hypophosphorous acid (salt), wherein the phosphorus compound contains 0 to 0.3% by mass of a phosphorous acid (salt) based on 100% by mass of the phosphorus compound, and the aqueous poly(meth)acrylic acid (salt) solution contains 0 to 10000 ppm of an inorganic anion and a process for the preparation thereof.

Aqueous poly(meth)acrylic acid (salt) solution and process for preparing same

An aqueous solution containing a poly(meth)acrylic acid-based polymer which shows excellent dispersibility for inorganic substances, satisfactory long-term dispersibility, and a favorable color is provided. The aqueous solution of the present invention is an aqueous solution comprising a poly(meth)acrylic acid-based polymer, the poly(meth)acrylic acid-based polymer including carboxyl groups, wherein in 100 mol % of the carboxyl groups, 30 to 85 mol % of the carboxyl groups are in an alkali metal salt form of the carboxyl groups, and 15 to 70 mol % of the carboxyl groups are in an acid form of the carboxyl groups, the poly(meth)acrylic acid-based polymer containing a phosphorus-containing group, the poly(meth)acrylic acid-based polymer having a weight average molecular weight of 2000 to 9000, the aqueous poly(meth)acrylic acid-based polymer solution having a concentration of inorganic anions, each including a sulfur or phosphorus atom, of 1000 to 10000 ppm relative to the aqueous poly(meth)acrylic acid-based polymer solution.

Aqueous poly(meth)acrylic acid-based polymer solution

Betaine compound and process for production thereof

A process for preparing an aqueous resin dispersion includes the steps of copolymerizing a polymeric monomer whose ratio of (meth) acrolein to a total amount of the (meth) acrolein and a vinyl monomer is in the range from 10 weight % to 80 weight % in an organic solvent to obtain a copolymer solution, dispersing the obtained copolymer solution in an aqueous medium and removing an unreacted (meth) acrolein. Since the above process can extremely reduce contents of the unreacted (meth) acrolein and of an oligomer whose number-average molecular weight is less than 1000, an aqueous resin dispersion where problems of a pungent smell, toxicological properties, etc. due to the (meth) acrolein and the oligomer are eliminated can be provided.

Process for preparing an aqueous resin dispersion and an aqueous resin

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Suita, Japan

Junichi Chosa