Polyacrylic acid (salt) water-absorbent resin, production process thereof, and acrylic acid used in polymerization for production of water-absorbent resin

A water-absorbent resin, acrylic technology, applied in the field of acrylic

Active Publication Date: 2008-03-26
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in Patent Documents 12 and 13, there is a problem that the obtained water-absorbent resin is colored (turned yellow) due to oxidation of methoxyphenol and furfural, which are important in the production of water-absorbent resin. Included in a monomer in the process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0193] Commercially available acrylic acid (a special grade reagent from Wako Pure Chemical Industries, Ltd.; p-methoxyphenol content = 200 ppm by weight), obtained by catalytic gas phase oxidation, was placed in a 50 The column bottom of the high-boiling impurity separation column with a double-flow perforated disc, followed by distillation with a reflux ratio of 1, and then redistilled, thereby obtaining an acrylic acid composition containing acrylic acid with a concentration of not less than 99% and trace impurities (mainly water) (1) (also known as purified acrylic acid).

[0194] In the acrylic composition (1), the content of p-methoxyphenol is ND (less than 1 ppm by weight). Meanwhile, the content of protopulsatin, furfural, β-hydroxypropionic acid, and acrylic acid dimer were each ND (less than 1 ppm by weight). In the acrylic composition (1), the content of phenothiazine is 0 ppm by weight, the content of acetaldehyde is not more than 1 ppm by weight, the content of m...

Embodiment 2 to 5

[0196] By adding 10 ppm by weight, 100 ppm by weight, 1000 ppm by weight, and 10000 ppm by weight of toluene (relative to the solid content of acrylic acid) to the acrylic acid composition (1) obtained in Production Example 1, respectively, Acrylic compositions (2) to (5) having respective predetermined toluene contents were obtained.

Embodiment 6 to 8

[0198] By adding respectively 10 ppm by weight, 1000 ppm by weight, and 10000 ppm by weight of diphenyl ether (relative to the solid content of acrylic acid) to the acrylic acid composition (1) obtained in Production Example 1, each Acrylic compositions (2) to (5) having a predetermined diphenyl ether content.

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Abstract

The present invention allows for production, with a high productivity, of a water-absorbent resin having an improved relationship between absorption capacity and water-soluble polymer which are conflicting properties of the water-absorbent resin, being easily controlled for polymerization reaction, being of no odor, being less colored, and being of high absorption properties. In the present invention, acrylic acid composition is neutralized with a basic composition having an iron content of 0.2 to 5 ppm by weight (relative to a basic compound exclusive of a solvent); and then polymerizing a resultant neutralized product, the acrylic acid composition including: (i) a methoxyphenol content of 10 to 200 ppm by weight relative to the weight of acrylic acid; and (ii) at least one compound content of which is 0 to 10 ppm by weight relative to the weight of acrylic acid, the compound being selected from the group consisting of protoanemonin and furfural.

Description

technical field [0001] The present invention relates to a polyacrylic acid (salt) water-absorbing resin, its production method, and acrylic acid used in polymerization for producing the water-absorbing resin. More specifically, the present invention relates particularly to (i) a water-absorbent resin having an improved relationship between water-absorbent capacity and a water-soluble polymer, which are conflicting characteristics of the water-absorbent resin, (ii) a production method of the water-absorbent resin, and (iii) Acrylic acid used in the production method of the water-absorbent resin. Background technique [0002] In recent years, water-absorbent resins having high water-absorbency have been developed, and are often mainly used for one-time use, for example, as absorbent articles (for example, disposable diapers and toilet paper), and additionally as water-retaining agents for agriculture and gardening and sealing materials for industry. For such water-absorbent ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F20/06C08F6/00C08F8/00
Inventor 藤丸洋圭石崎邦彦中原整
Owner NIPPON SHOKUBAI CO LTD
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