摘要:
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.
摘要:
The present invention is a method for the production of a water absorbent resin, which comprises preparing a monomer component possessing an ability to form a cross-linked structure and convert itself into a hydrated gel polymer during the course of aqueous solution polymerization, possessing an acid group-containing monomer content of at least 50 mol %, and having 10 to 50 mol % of said acid group-containing monomer neutralized and subjecting said monomer component to aqueous solution polymerization within a reaction vessel having a plurality of rotary shafts each fitted with stirring blades.
摘要:
A method for the production of a hydrophilic polymer having a small residual monomer content from a hydrated gel polymer, which method comprises drying said hydrated gel polymer by contact thereof with a gas containing at least steam and having a dew point in the range of 50.degree. to 100.degree. C. at a temperature in the range of 80.degree. C. to 250.degree. C., and a hydrophilic polymer obtained therefrom.
摘要:
The present invention is to provide a drying method by which both cost reduction and superior physical properties can be attained in a step which comprises subjecting a water-containing gel-like crosslinked polymer obtained by polymerizing an aqueous monomer solution to fine granulation during or after the polymerization, and drying the resultant particulate water-containing gel-like crosslinked polymer with a through-circulation band dryer. The method has a feature in that the drying conditions over a period from a time of introducing the particulate water-containing gel-like crosslinked polymer into a drying zone of the through-circulation band dryer to a time of reaching a solid content concentration thereof to 80% by weight, satisfy that (1) a difference of temperature between a temperature of hot air blown to a particulate hydrogel layer and a temperature measured after the hot air passes through the particulate hydrogel layer is 20 to 70° C.
摘要:
A water-absorbent composition includes: a specific plant extract; a water-absorbent resin whose surface portion and/or periphery thereof is treated; and/or a water-absorbent resin having a specific property. Specifically, it is preferable to use a water-absorbent resin having three characteristics: (1) a specific neutralization rate, (2) a specific particle diameter, and (3) a specific plant extract. The water-absorbent composition has a superior deodorant performance and an absorbent characteristic when the water-absorbent composition is used (provided) in an absorbing product such as a paper diaper, thereby providing a superior deodorant performance and a superior absorbent characteristic to the foregoing absorbing product.
摘要:
The subject invention provides a hydrophilic polymer (water-absorbing resin) which is superior in performance and productivity. According to the production method of the present invention, a hydrophilichigh-molecular-weight compound is dispersed in an aqueous solution containing a hydrophilic monomer. The dispersed hydrophilic high-molecular-weight compound is dissolved by heat of neutralization (heat of hydration) and/or heat of polymerization generated in the process of producing a hydrophilic polymer.
摘要:
A method for disintegrating a hydrate polymer characterized by disintegrating a hydrate polymer having a solid content in the range of 50-70 wt. % with a screw extruder while supplying 0.1-30 parts by weight of water per 100 parts by weight of the polymer to the extruder. Since the product of disintegration is prevented from inducing mutual adhesion, it does not form masses of conglomeration when it is dried.
摘要:
A particulate water absorbing agent of the present invention includes a water absorbent resin, having a cross-linking structure, whose surface has been cross-linked by adding a surface treatment agent, wherein: (i) a mass average particle diameter (D50) ranges from 200 to 600 μm and 95 to 100 wt % of a particulate water absorbing agent whose particle diameter ranges from less than 850 μm to not less than 150 μm is contained with respect to 100 wt % of whole the particulate water absorbing agent, and (ii) a logarithmic standard deviation (σζ) of particle size distribution ranges from 0.25 to 0.45, and (iii) a compressibility rate defined by a following equation ranges from 0 to 18%, and (iv) a surface tension of a supernatant liquid obtained in 4 minutes after dispersing 0.5 g of the particulate water absorbing agent in 50 ml of physiological saline whose temperature is 20° C. is 55 mN/m or more, the compressibility rate (%)=(P−A)/P×100 where P represents a tapped bulk density of the particulate water absorbing agent and A represents a loose bulk density of the particulate water absorbing agent.
摘要:
The subject invention produces a water-absorbent resin by carrying out stationary polymerization of an ethylenically-unsaturated monomer containing acrylic acid and/or acrylate; cutting the resulting hydrous gelatinous polymer; and drying the hydrous gelatinous polymer which mainly contains angular particles having 6 smooth planes. The resulting water-absorbent resin particles are not aggregate, and can be efficiently dried. By coating at least a part of the surface of each of the particles with an adhesion block agent before, after, and/or at the time of cutting process, the adhesion preventing effect further increases.
摘要:
The present invention provides a production process by which a water-absorbent resin of excellent quality can be obtained at a low cost by reasonable steps in aqueous solution polymerization. The process for producing a water-absorbent resin comprises the step of polymerizing an aqueous solution of water-absorbent resin-forming monomers including acrylic acid and/or its sodium salt as major components, wherein: (1) the aqueous solution has a monomer component concentration of not less than 45 weight %; (2) the polymerization is carried out while water is evaporated so that the ratio (concentration ratio) between a solid component concentration in a hydropolymer as formed by the polymerization and a solid component concentration in the aqueous monomer solution will not be less than 1.10; and (3) the solid component concentration in the hydropolymer as formed by the polymerization is not more than 80 weight %.