Biodegradable Water Absorbent with Clay Mineral Reinforcement

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Solution Overview

Problem

Existing methods for producing biodegradable water absorbents result in products with low gel strength and poor liquid permeability due to inadequate crosslinking and dispersion of clay minerals, leading to issues with continuous liquid absorption and gel blocking.

Innovation Solution

A method involving the crosslinking of naturally derived polymers, such as poly(glutamic acid), with a clay mineral like montmorillonite, where the clay mineral is incorporated within the polymer particles to enhance gel strength and liquid absorption, using a specific crosslinking agent and condensation aids to achieve uniform dispersion and increased interlayer distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If poly(glutamic acid) is crosslinked with a small amount of polyamine, then a gel with high swelling is obtained, but the gel strength becomes low and continuous liquid permeability is inhibited

Engineering Contradiction:
Improveswelling capacityVSAvoidgel strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent changes the crosslinking parameters by using a specific molar ratio of polyamine to poly(glutamic acid) (0.01-0.1 mol/mol), controlling the crosslinking degree to achieve optimal balance between swelling capacity and gel strength. This parameter optimization prevents excessive crosslinking that would reduce swelling while avoiding insufficient crosslinking that would weaken gel structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite gel system by incorporating clay minerals (such as montmorillonite) into the crosslinked poly(glutamic acid) network. This composite structure enhances gel strength through the reinforcing effect of clay particles while maintaining high swelling capacity, and the clay layers help prevent gel blocking by providing additional pathways for liquid permeability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If gel strength is increased to improve liquid permeability, then continuous liquid absorption is enhanced, but gel blocking occurs more easily

Engineering Contradiction:
Improvecontinuous liquid absorptionVSAvoidgel blocking
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the crosslinking parameters by controlling the polyamine dosage and crosslinking conditions to achieve a balanced gel structure. The crosslinking degree is adjusted to provide sufficient gel strength for liquid permeability while avoiding excessive crosslinking that would cause gel blocking. The patent specifies precise molar ratios and crosslinking time parameters to achieve this balance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces clay minerals as intermediary structures within the gel network. These clay particles act as spacers and structural support elements that maintain open channels for liquid flow, preventing gel blocking while contributing to overall gel strength. The clay layers create a hierarchical structure that facilitates continuous liquid absorption.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If clay mineral content is increased to improve liquid permeability, then dispersion uniformity decreases and aggregation occurs

Engineering Contradiction:
Improveliquid permeabilityVSAvoiddispersion uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent performs preliminary surface treatment of clay minerals before incorporation into the polymer matrix. The clay particles are pre-modified or pre-dispersed in appropriate media to improve their compatibility with poly(glutamic acid). This preliminary preparation ensures uniform distribution of clay particles during the crosslinking process and prevents aggregation, maintaining both liquid permeability and dispersion uniformity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses surface modifiers or coupling agents as intermediaries between the clay minerals and the polymer matrix. These intermediary substances improve the interfacial adhesion and compatibility between hydrophilic clay particles and the polymer network, ensuring uniform dispersion. The intermediaries prevent clay aggregation by reducing particle-particle interactions and enhancing particle-matrix interactions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The resulting water absorbent exhibits high gel strength, excellent absorption factor, and improved gel liquid flow speed, preventing gel blocking and ensuring effective continuous liquid absorption.

Implementation Method 1

crosslinking of poly(glutamic acid) with a polyamine

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

using a water-soluble carbodiimide and an N-hydroxysuccinic acid imide as a condensation agent and condensation adjuvant during crosslinking

Methodology Applied
Scientific EffectCondensation reaction: Chemical Bonding

Implementation Method 3

excellent swelling and moisture retention properties

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

biodegradable water absorbent obtained from a crosslinked naturally derived polymer and a clay mineral

Methodology Applied
Scientific EffectSwelling: Hydrogel

Implementation Method 5

the clay mineral is present inside the particle... obtained by a crosslinking reaction in an aqueous solution, and a clay mineral is dispersed in the aqueous solution

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentEP3228383B1Biodegradable water absorbent
Publication Date: 2019.12.25 UNI CHARM CORP
  • EP3228383B1 patent drawingFigure 1
  • EP3228383B1 patent drawingFigure 2(a)~2(i)
  • EP3228383B1 patent drawingFigure 3

AI summary

Provided is a biodegradable water absorbent having high gel strength and exhibiting an excellent absorption factor and excellent liquid passage rate through a gel. A water absorbent comprising a cross-linked naturally derived polymer and a clay mineral, the water absorbent being characterized in that the cross-linked naturally derived polymer and the clay mineral form particles, the clay mineral is present in the interior of the particles, and the clay mineral content constitutes 10-100 parts by mass (when dry) relative to 100 parts by mass (when dry) of the cross-linked naturally derived polymer. It is possible to produce this water absorbent by preparing a starting material fluid in which the naturally derived polymer is dissolved and the clay mineral is dispersed, adding a cross-linking agent to the starting material fluid, and cross-linking the naturally derived polymer.