Disclosed are water-absorbent resin particles comprising a crosslinked polymer comprising a monomer unit derived from a water-soluble ethylenically unsaturated monomer, wherein an initial swelling force as measured according to a swelling force test conducted by a predetermined method is 8 N or more, and further, a ratio of the particles having a particle diameter of more than 250 μm and 850 μm or less is 70% by mass or more and a ratio of the particles having a particle diameter of 250 μm or less is 20% by mass or less, with respect to the total amount of the water-absorbent resin particles.

The invention relates to a novel method for the continuous production of anionic polymers by radical polymerization. The polymers produced by said method have a controlled molecular weight.

The invention relates to a novel method for the continuous production of anionic polymers by radical polymerization. The polymers produced by said method have a controlled molecular weight.

A process for preparing a composition by free-radical polymerization of a monomer composition comprising: a) at least one ethylenically unsaturated carboxylic acid containing monomer or anhydride thereof; b) optionally at least one ethylenically unsaturated monomer different from a) but copolymerizable therewith; and c) at least one crosslinking monomer containing at least two ethylenically unsaturated groups. The monomer composition is polymerized in an organic medium having a solubilizing effect on one or more of the monomeric ingredients, but substantially none on the resulting polymer. The polymerization is conducted in the presence of a free radical forming catalyst and at least one steric stabilizing polymer polymerized from a vinyl lactam and a copolymerizable monomer selected from a short chain alkyl ester of (meth)acrylic acid, a long chain alkyl ester of (meth)acrylic acid, and combinations thereof.

A process of producing methacrylic acid and/or derivatives thereof including the following steps: (a) biologically converting isobutyryl-CoA into methacrylyl-CoA by the action of an oxidase; and (b) converting methacrylyl-CoA into methacrylic acid and/or derivatives thereof. The invention also extends to microorganisms adapted to conduct the steps of the process.

A process of producing methacrylic acid and/or derivatives thereof including the following steps: (a) biologically converting isobutyryl-CoA into methacrylyl-CoA by the action of an oxidase; and (b) converting methacrylyl-CoA into methacrylic acid and/or derivatives thereof. The invention also extends to microorganisms adapted to conduct the steps of the process.

[Object] To provide a method for stably producing a water-absorbent resin in powder form or particle form, which has excellent physical properties such as water absorption performance and the like, without any production trouble.

[Solution] A method for producing a water-absorbent resin includes mixing a monomer composition, which contains at least a monomer and a pyrolytic polymerization initiator, with an organic solvent, a temperature of the organic solvent is not lower than 70° C. at time of mixing, and when a mass per unit time of the monomer in the monomer composition to be mixed with the organic solvent is expressed as an amount per unit volume of the organic solvent, a lower limit is 0.01 g/ml/min, and an upper limit is 0.2 g/ml/min.

[Object] To provide a method for stably producing a water-absorbent resin in powder form or particle form, which has excellent physical properties such as water absorption performance and the like, without any production trouble.

[Solution] A method for producing a water-absorbent resin includes mixing a monomer composition, which contains at least a monomer and a pyrolytic polymerization initiator, with an organic solvent, a temperature of the organic solvent is not lower than 70° C. at time of mixing, and when a mass per unit time of the monomer in the monomer composition to be mixed with the organic solvent is expressed as an amount per unit volume of the organic solvent, a lower limit is 0.01 g/ml/min, and an upper limit is 0.2 g/ml/min.

Provided herein are methods of producing acrylic acid from bPL. Such methods involve the use of a heterogeneous catalyst, such as a zeolite at vapor phase conditions. The method may use a fixed bed, moving bed or fluidized contacting zone as the reactor configurations.

Provided herein are methods of producing acrylic acid from bPL. Such methods involve the use of a heterogeneous catalyst, such as a zeolite at vapor phase conditions. The method may use a fixed bed, moving bed or fluidized contacting zone as the reactor configurations.