Superabsorbent Hydrogel Extrusion for Fast, Stable Absorption
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Solution Overview
Problem
Existing superabsorbent polymer production methods fail to balance high absorption speed with reduced thixotropic behavior, leading to instability and potential leakage in personal hygiene products.
Innovation Solution
A method involving the use of a hole plate in the extrusion process with a specific design rule (5.5<2.10686036*(I/d)^0.774457*(V/A)^-0.117802<1.3) to control stress during extrusion, enhancing yield stress and absorption speed while minimizing thixotropy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional extrusion methods are used to produce superabsorbent polymers, then production efficiency is maintained, but the gel exhibits thixotropic behavior leading to instability and potential leakage
Solution Approach 1:
The patent applies parameter changes by optimizing the hole plate geometry with specific mathematical relationships (L/d ratio between 0.5-2.0 and A/V ratio between 5-20) to control extrusion stress. This modifies the physical parameters of the extrusion process to eliminate thixotropic behavior while maintaining production efficiency, directly resolving the contradiction between gel stability and process complexity.
2Productivity
If high absorption speed is achieved through rapid extrusion, then productivity increases, but yield stress decreases leading to gel instability
Solution Approach 1:
The patent changes the extrusion parameters by establishing specific geometric ratios for the hole plate (L/d and A/V ratios) that optimize the balance between extrusion speed and yield stress maintenance. This allows high productivity through rapid extrusion while preserving sufficient yield stress to prevent gel instability.
Solution Approach 2:
The patent applies dynamics by creating a dynamic equilibrium in the extrusion process where the hole plate geometry dynamically balances the competing requirements of fast extrusion (for productivity) and stress control (for yield stress maintenance). The specific geometric ratios enable the system to achieve both high absorption speed and gel stability simultaneously.
3Speed
If extrusion stress is increased to improve absorption speed, then productivity increases, but thixotropic behavior increases causing gel breakdown
Solution Approach 1:
The patent applies parameter changes by optimizing the hole plate geometric parameters (L/d ratio of 0.5-2.0 and A/V ratio of 5-20) to control the distribution and magnitude of extrusion stress. This ensures that absorption speed is improved through efficient extrusion while the stress remains below the threshold that would trigger thixotropic gel breakdown, maintaining composition stability.
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 produces superabsorbents with improved yield stress, absorption speed, and balanced properties, ensuring stable performance in personal hygiene products by maintaining elasticity under load and preventing sudden gel instability.
Implementation Method 1
Existing superabsorbent polymer production methods fail to balance high absorption speed with reduced thixotropic behavior, leading to instability and potential leakage in personal hygiene products
Implementation Method 2
During extrusion, the hydrogel is forced to pass the through holes axially to obtain an extruded hydrogel
Implementation Method 3
During polymerization, the monomer builds up polymer-chains which are crosslinked by the crosslinker to form a three-dimensional polymer network
Implementation Method 4
When absorbing water, the superabsorbent swells impetuously; the water is caged within its polymeric network so that the water-laden superabsorbent forms a hydrogel
Data Source
AI summary
Present invention deals with a method for preparing water-absorbing polymers, so called superabsorbents. The invention is based on the finding that extruding hydrogel through a hole plate (13) obeying a complex design rule diminishes negative influence of thixotropy and increases the absorption speed of the superabsorbent made from the hydrogel.