Particulate water absorber comprising water-absorbing resin as main component and process for manufacturing same

A manufacturing method and granular technology, applied in chemical instruments and methods, absorbent pads, other chemical processes, etc., can solve problems such as deterioration, liquid permeability, gel strength reduction, urine leakage from paper diapers, gel stability, etc.

Active Publication Date: 2016-06-08
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] When water-absorbent resin is used as the absorber of disposable diapers, the following problems have been pointed out: After absorbing urine, the water-absorbent resin deteriorates over time, the liquid permeability and gel strength decrease, and the problem of leakage of urine from the disposable diaper, that is, condensation. Glue Stability Issues

Method used

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  • Particulate water absorber comprising water-absorbing resin as main component and process for manufacturing same
  • Particulate water absorber comprising water-absorbing resin as main component and process for manufacturing same

Examples

Experimental program
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preparation example Construction

[0082] (2-1) Preparation process of monomer aqueous solution

[0083] This step is a step of preparing an aqueous solution (hereinafter referred to as "monomer aqueous solution") containing acrylic acid (salt) as a main component. In addition, this "main component" has the same meaning as the content described in (1-2) "polyacrylic acid (salt)". In addition, instead of the monomer aqueous solution, a monomer slurry liquid may be used as long as the water absorbing performance is not lowered, but for convenience, the monomer aqueous solution will be described below.

[0084] (acrylic acid)

[0085] In the present invention, acrylic acid is used as a monomer from the viewpoint of effects, but such acrylic acid usually contains trace components such as polymerization inhibitors and impurities.

[0086] As the above-mentioned polymerization inhibitor, preferably phenols, more preferably methoxyphenols, and even more preferably p-methoxyphenols, from the effect of inhibiting poly...

Embodiment

[0307] The present invention will be described in more detail with reference to the following examples, but the present invention is not to be construed as limited thereto, and examples obtained by appropriately combining the technical means disclosed in the respective examples are also included in the scope of the present invention.

[0308] It should be noted that, the electrical equipment (including the physical property measurement of the water absorbing agent) used in the production examples, examples and comparative examples used a power supply of 200V or 100V unless otherwise specified. In addition, each physical property of the water absorbing agent of this invention was measured under the conditions of room temperature (20-25 degreeC), and a relative humidity of 50%RH, unless otherwise specified.

[0309] [Measurement of Physical Properties of Particulate Water Absorbent]

[0310] The methods for measuring the physical properties of the particulate water-absorbing age...

manufacture example 1

[0402] In 5500 g of sodium acrylate aqueous solution (monomer concentration: 38 wt%) obtained by neutralizing acrylic acid containing 70 ppm of p-methoxyphenol with an aqueous sodium hydroxide solution and having a neutralization rate of 75 mol% (monomer concentration: 38 wt%) 2.5 g of polyethylene glycol diacrylate (average molecular weight: 523) was used as the monomer aqueous solution (1).

[0403] Next, the above-mentioned monomer aqueous solution (1) was put into a reactor formed by capping a double-arm jacketed stainless-steel kneader having an inner volume of 10 L and having two Σ-shaped blades while maintaining the liquid temperature at At 30°C, nitrogen was blown into the reactor to replace the inside of the system with nitrogen.

[0404] Next, while stirring the monomer aqueous solution (1), 14.2 g of a 20 wt % sodium persulfate aqueous solution and 2.4 g of a 1 wt % aqueous solution of L-ascorbic acid were added as polymerization initiators, respectively, and the po...

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Abstract

The invention aims to provide a water absorber which exhibits high gel stability, little scattering in gel stability among particle sizes, and good water absorption characteristics. A particulate water absorber which comprises a water-absorbing resin as the main component and a chelating agent and in which the constituent particles comprise particles having particle diameters of less than 300[mu]m and particles having particle diameters of 300 to less than 850[mu]m, each particle diameter being determined by JIS standard sieves, characterized in that: the content of the chelating agent is 0.001 to 5 parts by weight relative to 100 parts by weight of the solid matter of the water-absorbing resin; and the relationship (1) 1.2<C1 / C2<4.0 is satisfied.

Description

technical field [0001] The present invention relates to a particulate water-absorbing agent mainly composed of a water-absorbent resin, preferably used in absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads, and a method for producing the same. Background technique [0002] In recent years, in absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads, water-absorbent resins have been widely used as constituent materials for the purpose of absorbing body fluids such as urine and menstrual blood. As the above-mentioned water-absorbent resin, known are, for example, polyacrylic acid partially neutralized cross-linked product, starch-acrylic acid graft polymer hydrolyzate, vinyl acetate-acrylate copolymer saponified product, acrylonitrile copolymer or acrylic acid copolymer. A hydrolyzate of an amide copolymer, or a crosslinked body thereof, a crosslinked body of a cationic monomer, or the like. [0003] When water...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J20/26A61F13/49A61F13/53B01J20/30C08J3/12
CPCA61F13/53A61F13/15658A61F2013/530481B01J20/261B01J20/267B01J2220/68C08J3/12C08J3/245C08K3/06C08K5/0025
Inventor 片田好希石崎邦彦
Owner NIPPON SHOKUBAI CO LTD
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