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Polyacrylic acid (SALT) water-absorbing resin and manufacturing method therefor

A manufacturing method and technology of polyacrylic acid, which can be applied in the direction of absorbent pads, bandages, medical science, etc., can solve the problems of acrylic acid costing huge labor and cost, increasing the unpleasant smell of water-absorbing resin, and restricting production scale, etc., to achieve excellent physical properties, Effects of odor reduction and purification cost reduction

Active Publication Date: 2014-11-05
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, in order to reduce the impurity content, a huge amount of labor and cost are required for the purification of acrylic acid, and the process of expanding the production scale of water-absorbent resins using high-purity acrylic acid is greatly restricted by cost and procurement of acrylic acid. become a current technical problem
[0012] In addition, when the content of propionic acid, which is one of the impurities, is controlled to a certain amount or more during polymerization, the effect of increasing the water absorption capacity (CRC) of the water-absorbent resin can be obtained (Patent Documents 10 and 11), but on the other hand, If a large amount remains after polymerization, the unpleasant smell (sour smell) of the obtained water-absorbent resin will also increase.

Method used

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  • Polyacrylic acid (SALT) water-absorbing resin and manufacturing method therefor
  • Polyacrylic acid (SALT) water-absorbing resin and manufacturing method therefor
  • Polyacrylic acid (SALT) water-absorbing resin and manufacturing method therefor

Examples

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Embodiment

[0461] The present invention will be described more specifically based on the following examples and comparative examples, but the present invention is not limited to these examples, and examples obtained by appropriately combining technical features disclosed in the respective examples are also included in the present invention. In the range.

[0462] In addition, for simplicity, "liter" is expressed as "l" or "L", and "weight%" is expressed as "wt%". Furthermore, in the determination of trace components, the detection limit is denoted as N.D (Non Detected).

[0463] In addition, unless otherwise noted, the electronic equipment (including the measurement of the physical properties of the water-absorbent resin) used in the production examples, examples, and comparative examples used a power supply of 200V or 100V. In addition, unless otherwise noted, the various physical properties of the water-absorbent resin of the present invention were measured under conditions of room te...

manufacture example 1

[0513] Gaseous acrylic acid obtained by contacting gas-phase propylene oxide was collected with water to continuously obtain a 70% by weight aqueous solution of acrylic acid. Then, toluene was supplied from the top of a distillation tower (azeotropic dehydration tower) having 50 non-weir perforated plates, and the aqueous acrylic acid solution was supplied from the middle of the distillation tower, and azeotropic dehydration distillation was performed to obtain crude acrylic acid from the bottom of the tower. .

[0514] Then, the crude acrylic acid was continuously supplied to the bottom of a distillation tower (high-boiling-point impurity separation tower) having 50 perforated plates without weirs, and distillation was performed at a reflux ratio of 1. Then, after refining by redistillation, the polymerization inhibitor p-methoxyphenol was added, and the acrylic composition (a1) whose purity was 99 weight% or more was obtained.

[0515] In addition, as impurities in the acry...

manufacture example 2

[0517] Except that the number of weir-free perforated plates in the azeotropic dehydration tower of Production Example 1 was changed from 50 to 45, the same operation as in Production Example 1 was carried out to obtain an acrylic acid composition (a2) with a purity of 99% by weight or more. ).

[0518] As impurities in the acrylic composition (a2), acetic acid is 1800ppm, propionic acid is 400ppm, acrylic acid dimer is 110ppm, and protopulsatin (PAN) and aldehyde components are N.D (below the detection limit / below 1ppm). In addition, the content of p-methoxyphenol was 70 ppm.

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Abstract

Provided is a method for manufacturing a water-absorbing resin that has excellent water-absorption performance and is made from an acrylic acid that is suitable for large-scale production of said water-absorbing resin. Said method for manufacturing a polyacrylic acid (salt) water-absorbing resin includes a prescribed monomer-preparation step, polymerization step, drying step, and surface-crosslinking step, in that order. The acetic-acid concentration of the acrylic acid and the like supplied to the monomer-preparation step is 300 to 10,000 ppm (with respect to the acrylic acid), and an acetic-acid-concentration decrease percentage defined by a given formula is at least 35%.

Description

technical field [0001] The present invention relates to a polyacrylic acid (salt)-based water-absorbing resin and a method for producing the same. More specifically, it relates to a water-absorbent resin used as an absorbent body of sanitary products such as paper diapers and sanitary napkins, and a method for producing the same, and to a method for producing a polyacrylic acid (salt)-based water-absorbent resin having excellent performance at low cost. Background technique [0002] As a substance with high water absorption, water-absorbent resin has been developed in recent years and is mainly used for disposable purposes, such as absorbent bodies for sanitary products such as diapers and sanitary napkins, or water-retaining agents for agriculture and gardening, and water-stopping agents for industry Wait. [0003] At present, there are many kinds of multi-purpose water-absorbing resins, and there are also many monomers and hydrophilic polymers as their raw materials. Amo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/24C08F6/00C08F20/06C08J3/12
CPCC08J3/245A61L15/24C08F6/008A61L15/46C08F220/06C08F20/06C08J2333/02A61L15/60B01J20/267C08F6/10C08F120/06C08L33/02
Inventor 松本智嗣宫本崇史酒井豊文石井良武石崎邦彦
Owner NIPPON SHOKUBAI CO LTD
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