Particulate water absorbent and method for producing same

A manufacturing method and granular technology, applied in chemical instruments and methods, absorbent pads, other chemical processes, etc., can solve problems such as difficult performance and insufficiency, and achieve odorless urine resistance, excellent coloration prevention performance over time Effect

Inactive Publication Date: 2012-07-11
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Water-absorbent resins (particulate water-absorbing agents) developed focusing on these physical properties have the following problems: ", etc.), it is difficult to say that it can exhibit sufficient performance when it is actually used in absorbent bodies such as disposable diapers.
However, these methods are not sufficient in terms of excellent yellowing resistance, exerting excellent absorbing capacity, especially when AAP (water absorption capacity under pressure) is 20 [g] when using a reducing agent to achieve high physical properties / g] or above, or when the SFC (saline flow conductivity) is 30[×10 -7 cm 3 ·s·g -1 ] or more, or when the water absorption rate is set to 60 [sec] or less, unexplained odors other than the odor from the reducing agent may occur

Method used

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  • Particulate water absorbent and method for producing same
  • Particulate water absorbent and method for producing same
  • Particulate water absorbent and method for producing same

Examples

Experimental program
Comparison scheme
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Embodiment 1-1

[0520] Using the method described in US Patent No. 7,265,190 image 3 In the shown device, a hydrogel-like cross-linked polymer was produced according to the following method.

[0521] First, an aqueous monomer solution (1-1) was prepared comprising: 35.2 parts by weight of acrylic acid adjusted to 70 ppm of p-methoxyphenol content, 11.7 parts by weight of a 48% by weight aqueous sodium hydroxide solution, polyethylene glycol diacrylic acid 0.23 parts by weight of an ester (average number of ethylene oxide units: n=9), 0.22 parts by weight of an aqueous solution of 1% by weight of trisodium diethylenetriaminepentaacetate (abbreviation: DTPA·3Na) as a chelating agent, and 33.6 parts by weight of deionized water parts by weight.

[0522] Next, the monomer aqueous solution (1-1) adjusted to 40° C. was continuously supplied to the polymerization step using a metering pump. 177 parts by weight of a 48% by weight sodium hydroxide aqueous solution (0.7 ppm of iron content (with res...

Embodiment 1-2

[0528] Except that the addition amount of the 30% by weight sodium bisulfite aqueous solution described in Example 1-1 was changed from 1.66 parts by weight to 3.33 parts by weight, the granular water-absorbing agent (1-1) was obtained in the same manner as Example 1-1. 2). Table 1 describes the physical properties of the obtained particulate water-absorbing agent (1-2).

Embodiment 1-3

[0530]Except that the addition amount of the 30% by weight sodium bisulfite aqueous solution described in Example 1-1 was changed from 1.66 parts by weight to 0.166 parts by weight, a water-absorbing agent was obtained in the same manner as in Example 1-1. To 100 parts by weight, 0.6 parts by weight of a 50% by weight sodium lactate aqueous solution was further added and mixed to obtain a particulate water-absorbing agent precursor (1-3). Next, the obtained particulate water-absorbing agent precursor (1-3) was placed in a hot air dryer at 60°C for 30 minutes, and then passed through a JIS standard sieve with a mesh size of 710 μm to obtain a granular water-absorbing agent precursor (1-3). agent (1-3). The water content of the obtained particulate water-absorbing agent (1-3) was 2.0% by weight. The physical properties of the obtained particulate water-absorbing agent (1-3) are described in Table 1-1.

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Abstract

Disclosed is a particulate water absorbent for an absorbent material, which is mainly composed of a polyacrylic acid (salt) water absorbent resin and exhibits excellent water absorption performance, while having excellent performance of preventing coloring over time. The particulate water absorbent has no odor and is suitable for practical use. Also disclosed is a method for producing a particulate water absorbent mainly composed of a polyacrylic acid (salt) water absorbent resin, which comprises: a step of polymerizing an aqueous monomer solution that is mainly composed of an acrylic acid (salt) that contains 10-200 ppm of a methoxyphenol; a step of drying a hydrated gel-like crosslinked polymer that is obtained by the polymerization; and a surface crosslinking step. The method for producing a particulate water absorbent is characterized by comprising a step of adding a chelating agent and an inorganic reducing agent and by satisfying the following condition (a) and / or (b). (a) The method comprises a step of adding water-insoluble inorganic fine particles. (b) In the drying step and the surface crosslinking step, the moisture content of the polymer is controlled to 3-15% by weight.

Description

technical field [0001] The present invention relates to a granular water-absorbing agent mainly composed of a polyacrylic acid (salt)-based water-absorbing resin and a method for producing the same. More specifically, it relates to a particulate water-absorbing agent used as an absorber in paper diapers, sanitary napkins, etc., and a method for producing the same, and relates to a polyacrylic acid (salt ) is a particulate water-absorbing agent having a water-absorbing resin as a main component and a method for producing the same. Background technique [0002] In recent years, the industry has developed highly water-absorbent water-absorbent resins, which are mainly made into absorbent articles such as disposable diapers and sanitary napkins, and are used in disposable applications as water-retaining agents for agriculture and horticulture, and waterproof materials for industry. As a raw material of the water-absorbent resin, a large variety of monomers or hydrophilic polyme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J20/26A61F13/15A61F13/49A61F13/53B01J20/30C08J3/12C09K3/00
CPCC08J2333/02C08J3/12B01J2220/68C08J3/245B01J20/26C08J2300/14B29B9/12B29B2009/125C08J3/128
Inventor 中津留玲子池内博之北野贵洋石崎邦彦鸟井一司
Owner NIPPON SHOKUBAI CO LTD
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