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Method for producing water absorbent resin particle

A resin particle, water-absorbing technology, applied in the field of producing water-absorbing resin, can solve problems such as cost increase, property degradation, and insufficient particle size control, and achieve high productivity, enhanced basic properties, and low-cost effects

Active Publication Date: 2009-07-22
NIPPON SHOKUBAI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, in many cases, by republishing in US Patent No. 32649, GBP No. 2267094B, US Patent No. 5051259, US Patent No. EP No.0712659, EP No.1029886, U.S. Patent No.5462972, U.S. Patent No.5453323, U.S. Patent No.5797893, U.S. Patent No.6127454, U.S. Patent No.6184433, U.S. Patent No.6297335 and U.S. Reprinted Patent No. .37021 The technology proposed in an attempt to improve the properties of water-absorbent resins (for example, particle size control, increase in absorption rate, reduction in water extractables) accompanied by a reduction in productivity or the use of auxiliary raw materials, and thereby increase the water-absorbent resin. The production cost of the water-absorbent resin is undesirable from the viewpoint of disposable raw materials such as diapers.
[0008] In US Patent No.6228930, US Patent No.4950692, US Patent No.4970267, US Patent No.5064582, US Patent No.5432899, US Patent No.5455284, US Patent No.6867269, US Patent No.4734478 and US Patent No. The method for controlling the particle size proposed in Patent No. 5369148 still provides insufficient control of the particle size, and in addition the addition of a new particle size control step (agglomeration or fines recovery) is not only accompanied by an increase in cost, but also depends on the situation, Provides reduction in properties other than particle size
In addition, in US Patent No.6906159, US-2004-092688A and US-2004-234607A, there is also room for improvement

Method used

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  • Method for producing water absorbent resin particle
  • Method for producing water absorbent resin particle
  • Method for producing water absorbent resin particle

Examples

Experimental program
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Effect test

Embodiment approach

[0041] Coexistence here means that the hydrogel (a) and the hydrogel (b) are present together in the fine granulation device, and suitably, the hydrogel (a) and the hydrogel (b) are together during the fine granulation step The state that exists in a fine-grained device. For example, the following embodiments are included: the hydrogel (a) and the hydrogel (b) are simultaneously started to be loaded into the fine granulation equipment, and the loading is completed at the same time; (a) and hydrogel (b) are mixed, and then loaded into a fine granulation device. The mixing of hydrogel (a) and hydrogel (b) can be carried out continuously, semi-continuously or in batch mode.

[0042] Explanations regarding materials and equipment used in the fine granulation step will be given below in detail.

[0043] (Water-swellable, hydrogel-like crosslinked polymer (a))

[0044] In the present invention, the water-swellable, hydrogel-like crosslinked polymer (a) obtained through the crossl...

Embodiment

[0155] Based on Examples, the present invention will be described more specifically below, however, the present invention should not be limited to these Examples. It should be noted that hereinafter, for convenience, "parts by weight" may be abbreviated as "parts", "liter" may be abbreviated as "L", and "milliliter" may be abbreviated as "mL". In addition, "weight%" may be described as "wt.%". In addition, the water-absorbent resin is used (treated) under conditions of 25°C±2°C and a relative humidity of about 50%±5% RH. In addition, as a normal saline solution, a 0.90% by weight sodium chloride aqueous solution was used.

[0156] It should be noted that in the case of analyzing a commercially available product such as a water-absorbent resin in a disposable diaper and when it is in a hygroscopic state, it can be measured after adjusting the water content to about 5% by drying under an appropriate reduced pressure .

[0157] (centrifuge retention capacity (CRC))

[0158] I...

reference example 1

[0189] Prepare (A) 48.5wt.% sodium hydroxide aqueous solution, (B) 54.3wt.% acrylic acid aqueous solution, (C) polyethylene glycol diacrylate (average molecular weight 523) by 9.33wt.% respectively, 0.30 wt.% of hydroxycyclohexyl benzophenone, 0.37wt.% of 46wt.% trisodium diethylene triamine pentaacetate aqueous solution, 45.0wt.% of acrylic acid and 45.0wt.% of industrial pure water Solution, and the aqueous solution of (D) 3.0wt.% sodium persulfate, and each solution is packed in the groove 31 of storage aqueous solution (A), in the groove 32 of storage aqueous solution (B), the groove of storage solution (C) 33, and in the tank 34 for storing the aqueous solution (D) (see figure 2 ). The solution temperature in each tank was set as follows: 33°C for the aqueous solution (A), 11°C for the aqueous solution (B), 24°C for the aqueous solution (C), and 24°C for the solution (D). It should be noted that installing the pump 35 in figure 2 in each slot.

[0190] by using the ...

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Abstract

The present invention provides a method for producing a water absorbent resin particle, in high productivity, not only in a controlled manner of particle size but also enhancing fundamental property (absorption capacity or absorption capacity against pressure) of a water absorbent resin. A method for producing a water absorbent resin particle having the cross-linking polymerization step for an aqueous solution of an unsaturated monomer; the grain refining step for water-swellable, water-containing gel-like cross-linked polymer (a) obtained in the cross-linking polymerization step; the drying step for grain refined gel; and the crushing step for a dried substance, wherein, in the grain refining step for the water-swellable, water-containing gel-like cross-linked polymer (a), water-swellable, water-containing gel-like cross-linked polymer (b), having solid content or centrifuge retention capacity different from solid content or centrifuge retention capacity of the cross-linked polymer (a) by equal to or larger than 1%, is subjected to coexistence.

Description

technical field [0001] The present invention relates to a method for producing a water-absorbent resin, which is a water-swellable cross-linked polymer, and more particularly, the present invention relates to a method for producing a water-absorbent resin having a controlled particle size and a substantially Excellent properties such as absorption rate or extractables. Background technique [0002] Currently, water-absorbing resins (water-absorbing agents) such as cross-linked polymers of polyacrylates are widely used as constituent materials of hygienic articles such as disposable diapers or sanitary napkins, so-called incontinence pads and the like, which are intended to absorb body fluids. [0003] The water-absorbent resin needs to have excellent properties such as excellent fluid absorption capacity or water absorption speed, gel strength, gel fluid permeability in contact with aqueous fluids such as body fluids, etc., or excellent release from aqueous fluid-containing ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/12
CPCB29B17/00C08J3/12C08J2300/14Y02W30/62B29B9/06B29B9/12B29B7/422B29B7/428B29B7/60
Inventor 阪本繁入江好夫池内博之长泽诚石崎邦彦町田沙耶香
Owner NIPPON SHOKUBAI CO LTD
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