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

A dispersant comprising an aqueous poly(meth)acrylic acid and/or salt thereof solution containing a poly(meth)acrylic acid and/or salt thereof having a weight average molecular weight of 1000 to 10000 polymerized in the presence of a phosphorus compound containing a hypophosphorous acid and/or salt thereof,

• wherein the phosphorus compound contains a phosphorous acid and/or salt thereof and a total amount of the phosphorous acid and salt thereof is greater than 0% by mass to 0.3% by mass based on 100% by mass of the phosphorus compound, and
• the aqueous poly(meth)acrylic acid and/or salt thereof solution contains 0 to 10000 ppm of an inorganic anion.

An inorganic particle dispersion containing not less than 70% by mass of an inorganic particle, and prepared by a process comprising the step of adding an aqueous poly(meth)acrylic acid and/or salt thereof solution and grinding the inorganic particle,

• wherein the aqueous poly(meth)acrylic acid and/or salt thereof solution contains a poly(meth)acrylic acid and/or salt thereof having a weight average molecular weight of 1000 to 10000 polymerized in the presence of a phosphorus compound containing a hypophosphorous acid and/or salt thereof;
• the phosphorus compound contains a phosphorous acid and/or salt thereof and a total amount of the phosphorous acid and salt thereof is greater than 0% by mass to 0.3% by mass based on 100% by mass of the phosphorus compound;
• and the aqueous poly(meth)acrylic acid and/or salt thereof solution contains 0 to 10000 ppm of an inorganic anion.