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Water-absorbing resin manufacturing method, water-absorbing resin, water-absorbing agent, absorbent article

A manufacturing method and technology of water absorption, applied in the direction of absorbent pads, bandages, medical science, etc., can solve the problems of increasing, low diffusivity, hindering the diffusibility of absorbed liquid, etc.

Active Publication Date: 2016-04-20
SUMITOMO SEIKA CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, the water-absorbent resins obtained by these methods do not necessarily satisfy the above-mentioned high water-absorbing capacity, excellent water-absorbing speed and other performances, and there is room for improvement.
[0007] In addition, in the case of using a water-absorbent resin with low diffusibility of the absorbed liquid in an absorbent body containing the water-absorbent resin, the water-absorbent resin locally absorbs the absorbed liquid near the position where the absorbed liquid is supplied, and the swollen The water-absorbent resin becomes denser, resulting in more fluid blocking
Moreover, at this time, the gelled water-absorbent resin further hinders the diffusibility of the absorbed liquid, so that there is a reverse flow of the absorbed liquid (Japanese original text: reverse flow). ri) Tendency to increase in volume

Method used

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  • Water-absorbing resin manufacturing method, water-absorbing resin, water-absorbing agent, absorbent article
  • Water-absorbing resin manufacturing method, water-absorbing resin, water-absorbing agent, absorbent article
  • Water-absorbing resin manufacturing method, water-absorbing resin, water-absorbing agent, absorbent article

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0150]In Example 1, a round-bottomed cylindrical detachable flask with an inner diameter of 110 mm and a volume of 2 L was prepared. The flask was provided with a reflux condenser, a dropping funnel, a nitrogen gas introduction pipe, and a mixer with 4 impellers of 50 mm in diameter in two stages. Stirring impeller with inclined paddle impeller. In this flask, 300 g of n-heptane was added as a hydrocarbon dispersion medium, 0.74 g of sucrose stearate (Mitsubishi Chemical Foods Co., Ltd., RyotoSugarEster S-370) of HLB3 was added as a surfactant, and horseradish as a polymer dispersant. 0.74 g of anhydride-modified ethylene-propylene copolymer (Mitsui Chemicals, Inc., High Wax 1105A) was heated up to 80° C. while stirring to dissolve the surfactant, and then cooled to 50° C.

[0151] On the other hand, 92 g (1.02 moles) of an 80 mass % acrylic acid aqueous solution was placed in a 500-mL Erlenmeyer flask, and while cooling from the outside, 102.2 g of a 30 mass % sodium hydroxid...

Embodiment 2

[0158] In Example 2, except that the 2% aqueous solution of ethylene glycol diglycidyl ether added as a post-crosslinking agent was changed to 6.62 g (0.761 micromole), the same operation as Example 1 was carried out to obtain 232.9 g of water-absorbent resin in the form of secondary particles in which spherical primary particles were aggregated. The water-absorbent resin thus obtained was evaluated according to the above-mentioned various test methods.

[0159] In addition, in the obtained water-absorbent resin, the mass ratio of the particles of 150 to 850 μm to the entire water-absorbent resin was 97.8% by mass, and the mass ratio of the particles of 300 to 400 μm to the entire water-absorbent resin was 97.8% by mass. The proportion is 36.5% by mass.

Embodiment 3

[0161] In Example 3, the ethylene glycol diglycidyl ether as an internal crosslinking agent added to the monomer in the first stage was changed to 0.0202 g (0.116 micromole), and the stirring speed of the stirrer was set at 500 rpm to perform the first step. Except for the stepwise polymerization, the same operation as in Example 1 was carried out to obtain 231.0 g of a water-absorbent resin having a form of secondary particles in which spherical primary particles were aggregated. The water-absorbent resin thus obtained was evaluated according to the above-mentioned various test methods.

[0162] In addition, in the obtained water-absorbent resin, the mass ratio of the particles of 150 to 850 μm to the entire water-absorbent resin was 90.7% by mass, and the mass ratio of the particles of 300 to 400 μm to the entire water-absorbent resin was 90.7% by mass. The proportion is 24.2% by mass.

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Abstract

With respect to water-absorbent resins, there are provided a method of manufacturing a water-absorbent resin having an appropriate BET specific surface and a water-absorption rate and a water-absorbing agent and an absorbent article that are formed by using the water-absorbent resin. In a first aspect of the present invention, when reverse phase suspension polymerization of two steps or more is performed on a water-soluble ethylenically unsaturated monomer in a hydrocarbon dispersion medium in the presence of at least an azo compound, a peroxide and an internal-crosslinking agent,; the used amount of the internal-crosslinking agent at the time of the polymerization of a first step is adjusted to fall within a range of 0.015 to 0.150 mmol per mole of the water-soluble ethylenically unsaturated monomer used at the time of the polymerization of the first step and the polymerization is performed such that the BET specific surface area of secondary particles formed by agglomeration of primary particles obtained is controlled.

Description

technical field [0001] The present invention relates to a method for producing a water-absorbent resin constituting an absorber suitable for use in sanitary materials such as disposable diapers and sanitary products, the water-absorbent resin, a water-absorbent agent and an absorbent article using the water-absorbent resin. Background technique [0002] Water-absorbent resins have been widely used in sanitary materials such as sanitary products and disposable diapers in recent years. [0003] As such a water-absorbent resin, the acrylic acid partially neutralized salt polymer cross-linked product has excellent water-absorbing ability, and acrylic acid as its raw material is easily obtained industrially, so it can be produced at low cost with constant quality, and has the property that it is not easy to rot. , deterioration and other advantages, so it is considered to be the preferred water-absorbent resin. [0004] Examples of properties desired for water-absorbent resins i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A99Z99/00
CPCC08F2/32C08F2/20C08F2/44C08F4/04C08F6/18A61F2013/530481A61F13/49A61F13/53C08F2/18A61L15/24A61L15/60C08F120/06C08F2810/20C08J3/24C08J2333/02C08K3/22C08K3/34C08K3/36C08K2003/2227
Inventor 村上真启鄙山铁博薮口纮基横山秀树
Owner SUMITOMO SEIKA CHEM CO LTD
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