Irregular Sieve Classification for Water-Absorbing Resin Performance

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Solution Overview

Problem

Current methods for improving the water absorption performance of polyacrylic acid (salt)-based water-absorbing resins, particularly in terms of fluid retention capacity under pressure and liquid permeability, have limitations, with existing techniques focusing on other properties and requiring significant changes in raw materials or equipment investment.

Innovation Solution

The use of a classification step with a sieve having irregular polygonal or non-circular openings, specifically with a ratio of major to minor axis between 1.3 and 5, in the production process of particulate water-absorbing agents, enhances fluid retention capacity under pressure and liquid permeability without requiring substantial changes in raw materials or equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional classification methods are used, then productivity is maintained, but fluid retention capacity under pressure and liquid permeability are insufficient

Engineering Contradiction:
Improvefluid retention capacity under pressureVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the geometric parameters of the classification sieve openings from conventional circular shapes to irregular polygonal shapes with specific aspect ratios (1.3-5.0). This parameter change in opening shape and dimensions improves fluid retention capacity under pressure and liquid permeability while maintaining classification effectiveness and productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If new raw materials or equipment are introduced to improve water absorption performance, then fluid retention capacity under pressure improves, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improveliquid permeabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent improves liquid permeability by changing the physical parameters of the classification sieve (opening shape to irregular polygonal with aspect ratio 1.3-5.0) rather than introducing new raw materials or complex equipment. This approach enhances performance while keeping the manufacturing process and device complexity similar to conventional methods.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If classification is performed to improve particle size distribution, then manufacturing precision improves, but fluid retention capacity under pressure deteriorates

Engineering Contradiction:
Improveparticle size distributionVSAvoidfluid retention capacity under pressure
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies asymmetry by using irregular polygonal openings with specific aspect ratios (1.3-5.0) in the classification sieve. This asymmetric opening shape allows for effective particle size classification while simultaneously improving fluid retention capacity under pressure, resolving the contradiction between manufacturing precision and reliability.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3279239B1Method for producing particulate water-absorbing agent that has polyacrylic acid (SALT)-based water-absorbing resin as main component
Publication Date: 2022.06.01 NIPPON SHOKUBAI CO LTD
  • EP3279239B1 patent drawingFigure 1

AI summary

Provided is a method for producing a particulate water-absorbing agent, the method including a polymerization step for obtaining a water-containing gel-type crosslinked polymer by polymerizing an acrylic acid (salt)-based monomer aqueous solution, a drying step for obtaining a dry polymer by drying the water-containing gel-type crosslinked polymer, a sorting step for obtaining a water-absorbing resin powder of a specific particle size by sorting the polymer to be sorted, and a surface crosslinking step for surface-crosslinking the non-surface-crosslinked water-absorbing resin powder, wherein the sorting step is performed before and/or after the surface crosslinking step, and the shape of the holes of the sorting sieve used in the sorting step is a non-regular polygonal or non-circular shape.