Nippon Shokubai Co., Ltd.

Yusuke Watanabe

Kazushi Torii

Kozo Nogi

Kazuki Kimura

Masatoshi Nakamura

Kunihiko Ishizaki

Shigeru Sakamoto

Yoshifumi Adachi

Sayaka Machida

Toshimasa Kitayama

Reiko Nakatsuru

Taishi Kobayashi

Hiroyuki Ikeuchi

Satoshi Matsumoto

Koji Miyake

Kenji Kadonaga

Taku Iwamura

Kenji Tada

Hirofumi Shibata

Koji Honda

Taku Fujimoto

Atsuro Yoneda

Seiichi Suzuki

Sumio Okuda

Nobuya Tanaka

Kazumasa Konishi

Kohei Omori

Toru Nishioka

Teruhisa Nagashima

Keiji Inoue

Yuka Fujii

Koji Shibata

A method for filling a particulate water absorbing agent includes a filling step of filling a particulate water absorbing agent into a filling container and a vibrating step of vibrating the filling container at the outside of the filling container, the vibrating step being conducted at least one time between the start and the end of the filling step, in which a vibration condition in the vibrating step satisfies the following conditions (a) and (b):(a) vibration by a vibrating body in contact with the filling container has a vertical directional component and a vibrational angle is within 90&#xb0;&#xb1;30&#xb0;; and (b) total amplitude at no load and a vibration frequency at no load of the vibrating body are set so as to satisfy Equation 1-1 and Equation 2 or Equation 1-2 and Equation 2.

Method for filling particulate water absorbing agent and method for sampling filled particulate water absorbing agent

The present invention provides a contraction agent for a water-absorbing resin that is used as a proppant in stratum hydraulic fracturing, the contraction agent containing: a metal ion-containing substance and a breaking agent for water-absorbing resins used in stratum hydraulic fracturing; and an iron ion-containing substance and/or ascorbic acid, and/or a persulfate. Also provided is a kit for use in stratum hydraulic fracturing, the kit provided with a swelling agent containing a water-absorbing resin, an iron ion-containing substance, and ascorbic acid, the kit being for stratum hydraulic fracturing, wherein the kit consists of A) a proppant containing a water-absorbing resin, and B) a contraction agent for the water-absorbing resin containing a metal ion-containing substance.

Methods of liquefying and shrinking water-absorbable resins in a water-containing state

Provided is a water-absorbing agent which is less likely to cause gel blocking and is suitable for a sanitary product and an absorbent article each being thin and containing a large amount of a water-absorbing agent, and which, while maintaining or hardly losing the other physical properties (a fluid retention capacity and a bulk specific gravity) of the water-absorbing agent, simultaneously achieves a high water absorbing speed (e.g., FSR), a high fluid retention capacity under load, high liquid permeability, and salt tolerance. The water-absorbing agent is a polyacrylic acid (salt)-based water-absorbing agent whose surface and its vicinity are crosslinked by an organic surface crosslinking agent, characterized by satisfying the following (A)-(D): (A) Free Swell Rate (FSR) of at least 0.28 g/g/s, or Absorption Time (Vortex) of 42 seconds or less; (B) Absorption Against Pressure (AAP) of at least 20 g/g; (C) Salt Tolerance Index represented by 'Salt Tolerance Index=(CRCdw)/(CRCs)' where CRCdw is a centrifuge retention capacity (unit; g/g) for deionized water (dw), and CRCs is a centrifuge retention capacity (unit; g/g) for a 0.9 weight % saline, satisfying 'Salt Tolerance Index&#x2264;0.49&#xd7;CRCs&#x2212;7.47'; and (D) Bulk Specific Gravity of 0.55 to 0.70 g/cm.

Polyacrylic acid (salt) water absorbent, and method for producing same

An object of the invention is to provide a technique in which a decrease in physical properties is suppressed or consumer complaints are diminished. A method includes a filling step of filling a particulate water absorbing agent into a filling container and a vibrating step of vibrating the filling container at the outside of the filling container, the vibrating step being conducted at least one time between the start and the end of the filling step. A vibration condition in the vibrating step satisfies the following conditions: (a) vibration by a vibrating body in contact with the filling container has a vertical directional component and a vibrational angle is within 90&#xb0;&#xb1;30&#xb0;; and (b) total amplitude at no load and a vibration frequency at no load of the vibrating body are set so as to satisfy Equation 1-1 and Equation 2 or Equation 1-2 and Equation 2.

From a view pint of decreasing an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence due to an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct. There is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising storing a non-polymerized organic compound being a raw material (modified raw material) of a water absorbent resin powder in a heated state, thereafter, mixing the non-polymerized organic compound with other compound at a predetermined ratio and, further, mixing the mixture into a water absorbent resin powder.

Method for producing polyacrylic acid (salt)-based water absorbent resin powder

A water-absorbent resin composition is provided which shows only small reduction in liquid permeability and limited coloring over time or in relation to another factor. The water-absorbent resin composition (particulate absorbent agent) of the present invention contains: a polycarboxylate-based water-absorbent resin as a primary component, the resin having a crosslinked structure formed by polymerization of an acid group-containing unsaturated monomer; and multivalent metal cations (preferably, on surfaces of particles (i.e., the water-absorbent resin composition)) wherein: the multivalent metal cations other than Fe cations account for 0.001 to 1 mass % of the water-absorbent resin; and the ratio of the Fe cations to the multivalent metal cations other than the Fe cations is less than or equal to 5.00 mass %.

Water-absorbent resin composition, method of manufacturing the same, and absorbent article

The present invention relates to an absorbent suitable for use in a thin sanitary material/absorbent article having a high absorbent content and not prone to gel blocking, the absorbent having excellent liquid diffusibility (e.g. SFC) and minimal decrease in absorption ratio under pressure (e.g., AAP or PUP) even when a liquid permeation enhancer is added, and to a method for manufacturing the high-performance absorbent stably during actual production. The method is a method for manufacturing a polyacrylic acid (salt)-based absorbent, having a surface-crosslinking agent addition step for adding a solution of a surface-crosslinking agent, and a liquid permeation enhancer addition step for adding a liquid permeation enhancer, the liquid permeation enhancer addition step being performed after and/or at the same time as the surface-crosslinking agent addition step, the method characterized in that a surface crosslinking step for performing heat treatment in an atmosphere having a dew point of 45&#xb0; C. to 100&#xb0; C. is performed after or at the same time as the surface-crosslinking agent addition step.

Method for producing polyacrylic acid (salt)-based water absorbing agent, and water absorbing agent

A water-absorbent resin composition is provided which shows only small reduction in liquid permeability and limited coloring over time or in relation to another factor. The water-absorbent resin composition (particulate absorbent agent) of the present invention contains: a polycarboxylate-based water-absorbent resin as a primary component, the resin having a crosslinked structure formed by polymerization of an acid group-containing unsaturated monomer; and multivalent metal cations (preferably, on surfaces of particles (i.e., the water-absorbent resin composition)) wherein: the multivalent metal cations other than Fe cations account for 0.001 to 1 mass % of the water-absorbent resin; and the ratio (in terms of percentage) of the Fe cations to the multivalent metal cations other than the Fe cations is less than or equal to 5.00 mass %.

From a view point of reduction in an out of spec product after surface crosslinking, particularly, when an alkylene carbonate compound is used as a surface crosslinking agent, influence by an air temperature is great, and it is necessary to reduce ethylene glycol which is produced as a byproduct, and there is provided a process for producing a polyacrylic acid (salt)-based water absorbent resin powder, comprising

Provided is a production method for the particulate water-absorbing agent, which can collecting the fine powders generated during the producing process efficiently without worsening working environment, and also the particulate water-absorbing agent produced by the production method thereof. This production method includes (1) a polymerization step for obtaining a polymer gel, (2) a drying step for drying said polymer gel to obtain a particulate water-absorbing resin, (3) a classification step for sieving said particulate water-absorbing resin, (4) a surface cross-linking step for cross-linking the neighborhood of the surface of said particulate water-absorbing resin (5) a packaging step for filling a packaging material container with said particulate water-absorbing agent for packaging and (6) a transportation step for transporting the products produced in each of the steps to the other steps. In this production method, the fine powders contained in gas composed principally of air, in any of the steps, can be collected by use of a trapping material.

Method for producing particulate water-absorbing agent composed principally of water-absorbing resin

The present invention provides a water absorbing agent, including: water absorbent resin particles; and a modified cationic polymer compound containing a primary amino group and/or a secondary amino group, the modified cationic polymer compound being obtained by reacting, with a modifying agent, a cationic polymer compound containing the primary amino group and/or the secondary amino group, and the modifying agent containing two or more carbon atoms continuously linked, and one reactive group which reacts with the primary amino group and/or the secondary amino group. The present invention further provides a method for producing a water absorbing agent including water absorbent resin particles, the method including the step (i) of mixing the water absorbent resin particles with a modified cationic polymer compound.

Water absorbing agent and production method thereof

A water absorbent resin having less fine powder or powdery dust and a controlled particle size is provided, and the water absorption rate of the water absorbent resin is increased by a simple method at low cost, while maintaining or improving other physical properties such as liquid permeability. Disclosed is a method for producing a polyacrylic acid (salt)-type water absorbent resin powder, which includes, in sequence, a step of polymerizing an aqueous solution of acrylic acid (salt)-type monomer; a step of gel-crushing a gel of a water-containing gel-like crosslinked polymer during polymerization or after polymerization; a step of drying the water-containing gel-like crosslinked polymer; and a step of pulverizing and classifying the dried polymer, wherein water absorbent resin fine particles having a particle size of less than 150 &#x3bc;m or a hydrated-particles thereof is added to a step prior to the drying step, and in the drying step, hot air drying is carried out with a hot air having an average flow velocity of 1.0 to 3.0 [m/s], a dew point of 30&#xb0; C. to 100&#xb0; C., and a hot air temperature of 140&#xb0; C. to 235&#xb0; C.

Method for producing polyacrylic acid (salt) type water absorbent resin powder

A method includes the steps of: adding an organic surface cross-linking agent to a water absorbent resin having a cross-linked structure; adding a liquid permeability improving agent to the water absorbent resin concurrently with or after the addition of the organic surface cross-linking agent; and then adding a lubrication improving agent to the water absorbent resin. This provides a particulate water absorbing agent and a method for producing it, the particulate water absorbing agent being suitable for pneumatic transportation, suffering no decrease in the effect of the liquid permeability improving agent, and excelling in properties such as fluidity and damage resistance after the pneumatic transportation.

Particulate water absorbing agent and method for producing the same

The present invention provides a water absorbing agent, and a method for producing the water absorbing agent. The water absorbing agent includes water absorbent resin particles, an organic acid and/or salt thereof having carbon number of 10 or more and not more than 30 in its molecule, and a water-soluble polyvalent cation. The method includes the step (i) of mixing the water absorbent resin particles, the organic acid and/or salt thereof having carbon number of 10 or more and not more than 30 in its molecule, and the water-soluble polyvalent cation with one another.

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Himeji, Japan

Yusuke Watanabe