Water Absorbent Resin Solvent Separation via Pressure Compression

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Solution Overview

Problem

Conventional reverse phase suspension polymerization methods for producing water-absorbent resins face inefficiencies in solvent separation, leading to high costs, odor issues, and decreased physical properties due to residual organic solvents and surfactants, with filtration methods being inefficient and prone to clogging.

Innovation Solution

A method involving a polymerization step followed by a separation step where a pressure of at least 0.1 MPa is applied to transfer, compress, and discharge the hydrous gel crosslinked polymer using a discharge device with a pressure adjustment mechanism, effectively separating the polymer from the organic solvent and reducing residual liquid ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If reverse phase suspension polymerization is used to produce water-absorbent resin, then the resin can be produced with good water absorption properties, but a large amount of organic solvent is required which causes separation difficulties, high costs, and odor problems

Engineering Contradiction:
Improvewater absorption propertiesVSAvoidorganic solvent residue and odor
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the organic solvent from the polymerization system by using a continuous filtration device that separates the polymer particles from the solvent during the polymerization process, thereby eliminating solvent residue and odor while maintaining production efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a filtration device as an intermediary component between the polymerization reaction and the final product, which acts as a mediator to separate and remove the organic solvent without affecting the polymerization reaction or the water absorption properties of the resin

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional filtration methods are used to separate organic solvent from polymer, then separation can be achieved, but the filtration process is inefficient and prone to clogging

Engineering Contradiction:
Improveseparation capabilityVSAvoidfiltration efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent implements a continuous filtration process where the polymerization reaction and solvent separation occur simultaneously in a continuous flow system, eliminating the need for batch filtration and preventing clogging by maintaining constant flow and pressure conditions

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces conventional mechanical filtration systems with a continuous flow separation system that uses pressure-driven flow and specialized filter media to achieve efficient solvent removal without the clogging problems associated with traditional filtration

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If surfactant and dispersing agent are used to disperse monomer aqueous solution, then good dispersion is achieved, but these additives remain in the final product causing decreased surface tension and water absorption speed

Engineering Contradiction:
Improvedispersion qualityVSAvoidsurface tension and water absorption speed
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent extracts and removes surfactant and dispersing agent residues from the final product through the continuous filtration and washing process, thereby eliminating the negative effects on surface tension and water absorption speed while maintaining dispersion quality during production

Inventive Principle:
Principle #2Taking out (Extraction)

4Object-generated harmful factors

If evaporation method is used to remove organic solvent, then solvent removal can be achieved, but the process is troublesome and adds cost

Engineering Contradiction:
Improveorganic solvent removalVSAvoidprocess complexity and cost
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces the thermal evaporation process with a mechanical separation system using continuous filtration and pressure-driven flow, thereby removing the need for complex evaporation equipment and energy-intensive heating processes while achieving effective solvent removal

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances production efficiency, reduces residual solvent and surfactant amounts, improves surface tension, and minimizes clogging and energy consumption, resulting in a water-absorbent resin with improved properties and reduced odor.

Implementation Method 1

a pressure of not less than 0.1 MPa is applied to the hydrous gel crosslinked polymer

Methodology Applied
Scientific EffectPressure application: Pressure Increase

Implementation Method 2

a centrifugal filtration type, and a centrifugal sedimentation type have been proposed

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Data Source

PatentEP3398977B1Method for producing water absorbent resin
Publication Date: 2022.12.14 NIPPON SHOKUBAI CO LTD
  • EP3398977B1 patent drawingFigure 1
  • EP3398977B1 patent drawingFigure 2
  • EP3398977B1 patent drawingFigure 3

AI summary

[Object] To provide a method for producing a water-absorbent resin in powder form or particle form, which has excellent physical properties such as water absorption performance and the like, at high productivity. [Solution] A method for producing a water-absorbent resin includes: a polymerization step of polymerizing a monomer, which is a raw material of the water-absorbent resin, to obtain a hydrous gel crosslinked polymer dispersed in an organic solvent; and a separation step of separating the organic solvent and the hydrous gel crosslinked polymer. The separation step includes transfer, compression, and discharge of the hydrous gel crosslinked polymer.