Abstract: The invention provides: a water-absorbent resin granule-containing composition with resolution of various problems, as caused by water-absorbent resin fine powders, and with high granulation strength, and with no physical property deterioration due to granulation, and, if anything, with improvement of the absorption capacity under a load by granulation; and a process for producing the above granule. A water-absorbent resin primary particle and a water-absorbent resin granule are separately surface-crosslinked and then mixed, or mixed and then surface-crosslinked. The granulation is carried out by mixing a preheated aqueous liquid and a water-absorbent resin powder at a high speed or by supplying a water-absorbent resin powder downstream of an aqueous liquid with a continuous extrusion mixer.

Abstract: In the production of an acrylate polymer by the steps of preparing a water-soluble unsaturated monomer having a ratio of neutralization in the range of 30 to 100 mol % and containing 50 to 100 mol % of an acrylate and then polymerizing the monomer, a method for the production of a hydrophilic resin which comprises using a water-soluble unsaturated monomer having a &bgr;-hydroxy propionic acid (salt) content of not more than 1,000 ppm. The hydrophilic resin obtained by this method exhibits excellent physical properties and has only a small residual monomer content. Further, a residual monomer content neither occurs nor increases in any using conditions.

Abstract: The invention provides: a water-absorbent resin granule-containing composition with resolution of various problems, as caused by water-absorbent resin fine powders, and with high granulation strength, and with no physical property deterioration due to granulation, and, if anything, with improvement of the absorption capacity under a load by granulation; and a process for producing the above granule. A water-absorbent resin primary particle and a water-absorbent resin granule are separately surface-crosslinked and then mixed, or mixed and then surface-crosslinked. The granulation is carried out by mixing a preheated aqueous liquid and a water-absorbent resin powder at a high speed or by supplying a water-absorbent resin powder downstream of an aqueous liquid with a continuous extrusion mixer.

Abstract: In the production of an acrylate polymer by the steps of preparing a water-soluble unsaturated monomer having a ratio of neutralization in the range of 30 to 100 mol % and containing 50 to 100 mol % of an acrylate and then polymerizing the monomer, a method for the production of a hydrophilic resin which comprises using a water-soluble unsaturated monomer having a &bgr;-hydroxy propionic acid (salt) content of not more than 1,000 ppm. The hydrophilic resin obtained by this method exhibits excellent physical properties and has only a small residual monomer content. Further, a residual monomer content neither occurs nor increases in any using conditions.

Abstract: A method for the continuous production of a shaped hydrogel of absorbent resin is disclosed. This invention accomplishes the continuous production by continuously supplying in the form of a layer a monomer mixture capable of forming an absorbent resin by polymerization and polymerizing the layer of the monomer mixture. This method is characterized by retaining the rate of change of the thickness in the direction of width of the layer of hydrogel of absorbent resin at the time of formation of gel at a level of not more than 20%.

Abstract: The invention provides: a water-absorbent resin granule-containing composition with resolution of various problems, as caused by water-absorbent resin fine powders, and with high granulation strength, and with no physical property deterioration due to granulation, and, if anything, with improvement of the absorption capacity under a load by granulation; and a process for producing the above granule. A water-absorbent resin primary particle and a water-absorbent resin granule are separately surface-crosslinked and then mixed, or mixed and then surface-crosslinked. The granulation is carried out by mixing a preheated aqueous liquid and a water-absorbent resin powder at a high speed or by supplying a water-absorbent resin powder downstream of an aqueous liquid with a continuous extrusion mixer.

Abstract: An absorbent resin composition which shows high speed of absorption, excels in fluid permeability, and enjoys a high absorption capacity under load comprises primary particles of an absorbent resin and granulated particles of an absorbent resin having an average particle size smaller than the average particle size of the primary particles. An absorbent article contains the composition. The absorbent resin composition is produced by a method which comprises a step of producing granulated particles by granulating particles of absorbent resin having an average particle size in the range of 10 to 100 .mu.m and a step of mixing the resultant granulated particles of the absorbent resin with the primary particles of an absorbent resin having an average particle size in the range of 150 to 800 .mu.m.

Abstract: The present invention provides: a water-absorbing agent which has high absorption capacity, fast absorption speed, and excellent liquid permeability; and a production process and a use for such a water-absorbing agent. A water-absorbent fine particle having a lower absorption capacity than a water-absorbent resin particle is fixed to the surface of the water-absorbent resin particle, or portions having a higher crosslinking density than internal portions are discontinuously present in the neighborhood of the surface of the water-absorbent resin particle. In addition, the water-absorbing agent is produced using a water-absorbent crosslinking agent which is swellable in itself.

Abstract: A method for the production of an absorbent resin having a very small residual monomer content either by adding to an absorbent resin powder a substance capable of reacting with the residual monomer in the absorbent resin powder thereby forming an absorbent resin composition having a water content in the range of 10 to 70% by weight and heat-treating the absorbent resin composition at a temperature in the range of 100.degree. to 200 .degree. C. while retaining the water content of the absorbent resin or by adding to an absorbent resin powder a substance capable of reacting with the residual monomer in the absorbent resin powder thereby forming an absorbent resin composition having a water content in the range of 25 to 55% by weight, heat-treating the absorbent resin composition at a temperature in the range of 120.degree. to 200 .degree. C.

Abstract: A blood-absorbable resin composition characterized by having a blood area ratio relative to sheep blood of not less than 30% at a basis weight of 150 g/m.sup.2 and an absorbent article containing the composition. The blood-absorbable resin composition of this invention possesses an excellent ability to absorb blood and, therefore, is highly useful for sanitary napkins, tampons, medical blood-absorbable articles, trauma protectors, trauma healing materials, and reagents for treating liquid refuses from surgical operations.

Abstract: An absorbent resin exhibiting a high absorption ratio, having only a small water-soluble component content, and have excellent gel stability to withstand the effect of aging is produced. The production of the absorbent resin comprises a step of polymerizing a water-soluble monoethylenically unsaturated monomer by using, in a proportion of 0.01-0.3 mol % based on the amount of the water-soluble monoethylenically unsaturated monomer, a cross-linking agent having at least one group of the following formula I: ##STR1## wherein R.sup.1 is an alkylene group of 2 to 4 carbon atoms interposed between two polymerizing unsaturated groups in the molecular unit thereof and then heat-treating the resin produced by the polymerization at a temperature in the range of from 160.degree. to 230.degree. C.

Abstract: A method for the production of an absorbent resin, which method comprises mixing 100 parts by weight of (A) a hydrated gel of absorbent resin which is resulted from aqueous solution polymerization having a polymerization ratio in the range of from 60 to 99%, an average particle diameter in the range of from 0.1 to 200 mm, a water content in the range of from 30 to 90% by weight, and a temperature in the range of from 40.degree. to 110.degree. C., with from 1 to 50 parts by weight of (B) a substantially dry fine absorbent resin powder having an average particle diameter smaller than the average particle diameter assumed by said hydrated gel of absorbent resin (A) while in a dried state, then raising the polymerization ratio of said hydrated gel of absorbent resin (A) to a level higher than the polymerization ratio of said hydrated gel when being mixed.

Abstract: A method for the production of an acrylate by the neutralization reaction of acrylic acid and a basic substance, comprising sequentially (A) a step of supplying acrylic acid and said basic substance to water thereby subjecting them to a neutralization reaction while constantly retaining the neutralization ratio of acrylic acid within the neutralization reaction system in the range of 75 to 100 mol %, (B) a step of adjusting the neutralization ratio of acrylic acid within said neutralization reaction system in the range of 100.1 to 110 mol % by supplying said basic substance to said neutralization reaction system, (C) a step of retaining the neutralization ratio of acrylic acid within said neutralization reaction system in the range of 100.

Abstract: A method for the production of a salt-resistant absorbent resin, which comprises subjecting an aqueous solution of at least one monomer component (A) selected from the group consisting of unsaturated carboxylic acids and salts thereof to aqueous solution polymerization in the presence of from 1 to 30 parts by weight, based on 100 parts by weight of said monomer component (A), of an absorbent resin (B).

Abstract: An absorbent resin is produced by a method which comprises adding to 100 parts by weight of an absorbent resin powder an aqueous liquid containing 7 to 100 parts by weight of water and a reducing substance in the presence of 0.01 to 5 parts by weight of at least one additive selected from the group consisting of water-insoluble fine powders and surfactants. The absorbent resin thus produced excels in absorption properties and exhibits a low residual monomer content.

Abstract: A method for the production of an acrylate by the neutralization reaction of acrylic acid and a basic substance, comprising sequentially (A) a step of supplying acrylic acid and said basic substance to water thereby subjecting them to a neutralization reaction while constantly retaining the neutralization ratio of acrylic acid within the neutralization reaction system in the range of 75 to 100 mol %, (B) a step of adjusting the neutralization ratio of acrylic acid within said neutralization reaction system in the range of 100.1 to 110 mol % by supplying said basic substance to said neutralization reaction system, (C) a step of retaining the neutralization ratio of acrylic acid within said neutralization reaction system in the range of 100.