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Process for producing water-absorbing resin

A manufacturing method and a water-absorbing technology, which are applied in the field of absorbers and absorbent articles, can solve the problems of large water-absorbent resins, difficult to manufacture particle size, difficult to obtain appropriate particle size suitable for sanitary materials, etc., and achieve excellent liquid permeability. Effect

Active Publication Date: 2013-12-04
SUMITOMO SEIKA CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, conventional reversed-phase suspension polymerization has disadvantages such as difficulty in producing a water-absorbent resin with a large particle size and obtaining an appropriate particle size suitable for hygienic materials.

Method used

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  • Process for producing water-absorbing resin
  • Process for producing water-absorbing resin
  • Process for producing water-absorbing resin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0108] A round-bottomed cylindrical separable flask with a volume of 2 L equipped with a stirrer, dual paddle impellers, a reflux cooler, a dropping funnel, and a nitrogen inlet tube was prepared. 340 g of n-heptane was taken into the flask, and 0.92 g of sucrose stearate (Mitsubishi-Kagaku Foods Corporation, Ryoto Sugar Ester S-370) and maleic anhydride-modified ethylene / propylene copolymer (Mitsui Chemical Co., Ltd., Hivacs 1105A) 0.92 g, heated up to 80°C while stirring, and cooled to 50°C after dissolving the surfactant.

[0109] On the other hand, 92 g (1.02 moles) of an 80 mass % acrylic acid aqueous solution was taken into a 500 mL Erlenmeyer flask, and while cooling from the outside, 146.0 g of a 21 mass % sodium hydroxide aqueous solution was added dropwise to neutralize 75 mol %. , add 0.11g (0.41 mmol) of potassium persulfate as a radical polymerization initiator, 1.6 mg of ethylene glycol diglycidyl ether (0.09×10 -1 Millimoles, 0.9×10 relative to 100 moles of mon...

Embodiment 2

[0115] Change the addition amount of the first stage of the internal crosslinking agent in Example 1 to 2.8mg (0.16×10 -1 Millimoles, relative to 100 moles of monomers in the first stage is 1.6×10 -3 mol), and change the addition amount of the second stage to 0.03g (1.72×10 -1 Millimoles, relative to 100 moles of monomers in the second stage is 12.0×10 -3 mol), except that, the same operation as in Example 1 was carried out to obtain 230.1 g of a water-absorbent resin (B). The water-absorbent resin had a median particle size of 370 μm and a moisture content of 7.6%. Table 1 shows the measurement results of each property.

Embodiment 3

[0117] Change the internal crosslinking agent in Example 1 to N,N'-methylenebisacrylamide, and change the addition amount of the first stage to 4.6mg (0.30×10 -1 Millimoles, relative to 100 moles of monomers in the first stage is 2.9×10 -3 mol), and change the addition amount of the second stage to 0.03g (1.95×10 -1 Millimoles, relative to 100 moles of monomers in the second stage is 13.6×10 -3 mol), except that, the same operation as in Example 1 was carried out to obtain 229.5 g of a water-absorbent resin (C). The water-absorbent resin had a median particle size of 350 μm and a moisture content of 7.5%. Table 1 shows the measurement results of each property.

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Abstract

Provided is a process for producing a water-absorbing resin using a water-soluble ethylenically unsaturated monomer unit to which an internal cross-linking agent has been added, and in the process, primary particles obtained in a first inverse suspension polymerization step are aggregated in a second inverse suspension polymerization step. If the added amount of the internal cross-linking agent in the first polymerization step is set at A moles in relation to 100 moles of the water-soluble ethylenically unsaturated monomer unit used in the first polymerization step, and the added amount of internal cross-linking agent of the second polymerization step is set at B moles in relation to 100 moles of the water-soluble ethylenically unsaturated monomer unit used in the second polymerization step, the production process is characterized by A and B satisfying the relationships A<=5.0*10-3 and 2<=B / A<=10. This process can provide a water-absorbing resin with excellent liquid permeability, as well as an absorbent material and absorbent article comprising the same.

Description

technical field [0001] The present invention relates to a method for producing a water-absorbent resin and a water-absorbent resin obtained by the production method. More specifically, it relates to a method for obtaining a water-absorbent resin excellent in liquid-permeable performance in a method for producing a water-absorbent resin by reverse-phase suspension polymerization, a water-absorbent resin obtained by the method, and an absorbent body using the water-absorbent resin and absorbent articles. Background technique [0002] In recent years, water-absorbent resins have been widely used in various fields such as sanitary materials such as disposable diapers and sanitary products, agricultural and gardening materials such as water-retaining agents and soil improvers, and industrial materials such as water-stopping agents and anti-condensation agents. Among these fields, it is especially used for sanitary materials such as disposable diapers and sanitary products. As s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F2/32A61F13/49A61F13/53A61L15/60C08F20/06C08F20/56
CPCA61L15/24C08F2/32C08F220/06C08J3/24C08F220/56C08F222/1006A61L15/60C08F2/10A61F13/53Y10T428/31938C08L33/10C08F20/06C08F20/56A61F13/49
Inventor 鹰取润一
Owner SUMITOMO SEIKA CHEM CO LTD
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