Super Absorbent Polymer Surface Treatment Against Caking
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Solution Overview
Problem
Super absorbent polymers used in hygienic materials face challenges in maintaining high absorption rates while preventing agglomeration and caking, which are exacerbated in pulpless diapers where they are present in multiple layers.
Innovation Solution
A preparation method involving polymerization with an encapsulated foaming agent and addition of a carboxylic acid-based additive before coarse pulverization, followed by surface cross-linking, to enhance permeability and anti-caking efficiency without using inorganic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If super absorbent polymer particles are contained in multiple layers in pulpless diapers, then the absorption capacity for large amounts of liquid is improved, but the particles tend to agglomerate and cake, reducing permeability
Solution Approach 1:
A hydrophobic additive with specific molecular structure (containing hydrophobic group, hydrophilic group, and reactive group) is introduced as an intermediary substance. The hydrophobic group anchors to the polymer surface, the hydrophilic group provides moisture resistance, and the reactive group forms covalent bonds with surface hydroxyl groups. This intermediary layer prevents direct contact between polymer particles, eliminating agglomeration and caking while maintaining high absorption capacity in multi-layer structures.
Solution Approach 2:
The treatment applies local quality modification by creating a hydrophobic surface layer only on the outer surface of the super absorbent polymer particles, while the internal porous structure and hydrophilic properties remain unchanged. This localized modification prevents surface-level agglomeration and caking issues without compromising the bulk absorption capacity, enabling effective multi-layer configuration.
2Quantity of substance
If the super absorbent polymer absorbs moisture from air, then high absorption properties are exhibited, but agglomeration and caking occur between particles
Solution Approach 1:
The hydrophobic additive acts as a protective intermediary layer on the polymer surface. The molecular structure contains both hydrophilic groups (that allow controlled moisture absorption for high absorption properties) and hydrophobic groups (that prevent excessive moisture uptake from air). This dual-nature intermediary layer enables the polymer to maintain high absorption capabilities while resisting harmful caking caused by ambient moisture exposure.
Solution Approach 2:
The surface properties of the polymer are modified by changing the hydrophobicity parameter through additive incorporation. The additive's amphiphilic structure creates a surface with balanced hydrophobic-hydrophilic characteristics, altering the moisture interaction parameters. This parameter change allows the polymer to absorb necessary moisture for high absorption performance while preventing excessive moisture uptake that leads to caking.
3Object-generated harmful factors
If inorganic materials are used to improve permeability and anti-caking efficiency, then the physical properties are enhanced, but the absorption performance decreases
Solution Approach 1:
Instead of using inorganic materials that alter physical structure, the invention changes the chemical composition parameter by incorporating organic hydrophobic additives with specific molecular structures. These additives modify surface properties (hydrophobicity, surface energy) without affecting the internal porous structure, thereby improving permeability and anti-caking efficiency while preserving absorption performance.
Solution Approach 2:
The invention creates a composite structure at the molecular level by combining the super absorbent polymer with hydrophobic additives containing specific functional groups. This composite material approach integrates the benefits of both components: the polymer provides high absorption capacity while the hydrophobic additive provides improved permeability and anti-caking efficiency, avoiding the performance degradation caused by inorganic materials.
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 method results in a super absorbent polymer with improved permeability and anti-caking properties, maintaining high absorption rates without reducing performance, suitable for use in pulpless diapers.
Implementation Method 1
a step of forming a hydrogel polymer by cross-linking polymerization of a water-soluble ethylene-based unsaturated monomer having at least partially neutralized acidic groups in the presence of an internal cross-linking agent, an encapsulated foaming agent, and a polymerization initiator
Implementation Method 2
adding a hydrophobic additive having a specific molecular structure to the hydrogel polymer, followed by coarse pulverization
Implementation Method 3
a step of further cross-linking the surface of the base resin in the presence of a surface cross-linking agent to form a surface cross-linked layer
Implementation Method 4
The super absorbent polymer includes a plurality of hydrophilic moieties on its surface in order to exhibit high absorption properties for liquids, specifically water
Data Source
AI summary
The present disclosure relates to a preparation method of a super absorbent polymer. More specifically, it relates to a preparation method of a super absorbent polymer with improved permeability and anti-caking efficiency while having a high absorption rate by adding an additive having a specific structure to the hydrogel polymer polymerized in the presence of an encapsulated foaming agent, followed by coarse pulverization.