Super Absorbent Polymer Preparation via Dynamic Pressure Foaming
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Solution Overview
Problem
Existing methods for producing super absorbent polymers with improved absorption rates often require large amounts of blowing agents, which can lead to variations in polymer properties and generate undesired fine powders, complicating the recycling process and reducing physical properties.
Innovation Solution
A method involving the preparation of a monomer mixture with a water-soluble ethylene-based unsaturated monomer and internal cross-linking agent, where dynamic pressure is adjusted during transfer to a polymerization reactor to induce physical foaming, reducing the need for blowing agents and enhancing porous structure and absorption rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a carbonate-based blowing agent is used to form a porous structure by cross-linking polymerization, then the surface area of the super absorbent polymer is increased, but a large amount of undesired fine powder is generated during drying and pulverization, lowering physical properties and requiring recycling processes
Solution Approach 1:
The patent changes the blowing agent from carbonate-based to organic peroxide-based, which fundamentally alters the foaming mechanism. Organic peroxides decompose to produce gas bubbles that form pores during polymerization without generating fine powder, thus maintaining physical properties while achieving the desired porous structure and surface area
Solution Approach 2:
The patent employs a blowing agent (organic peroxide) that completely decomposes during the process, leaving no residual powder or byproducts. This disposable approach eliminates the need for recycling fine powders and simplifies the overall process
2Shape
If chemical foaming using a carbonate-based blowing agent is performed to increase surface area, then pores are formed in the polymer structure, but variation occurs in properties of the super absorbent polymer depending on polymerization temperature and time
Solution Approach 1:
The patent switches from carbonate-based to organic peroxide-based blowing agents, which have more predictable and stable decomposition characteristics. This change reduces sensitivity to polymerization temperature and time variations, leading to more consistent porous structure formation and reduced property variation
Solution Approach 2:
The organic peroxide is pre-added to the monomer mixture before polymerization begins. This preliminary incorporation ensures uniform distribution and controlled decomposition during the polymerization process, resulting in consistent pore formation regardless of minor temperature or time fluctuations
3Productivity
If the absorption rate of super absorbent polymer is improved by forming porous structure, then liquid absorption efficiency is enhanced, but a large amount of blowing agent is required which complicates the process and reduces physical properties
Solution Approach 1:
The patent changes the blowing agent type to organic peroxide, which produces gas bubbles more efficiently during polymerization. This results in effective porous structure formation with reduced blowing agent quantity, improving absorption rate without requiring large amounts of chemical additives
Solution Approach 2:
The patent replaces chemical foaming (carbonate-based) with a decomposition-based foaming mechanism (organic peroxide). This substitution reduces the quantity of blowing agent needed while achieving the same or better porous structure, thereby improving absorption rate without excessive chemical usage
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 enables the production of super absorbent polymers with excellent absorption rates and maintained physical properties while minimizing the use of blowing agents, suitable for use in sanitary materials like ultra-thin diapers.
Implementation Method 1
cross-linking and polymerizing the monomer mixture transferred to the polymerization reactor to form a hydrogel polymer
Implementation Method 2
adjusting a dynamic pressure applied to the monomer mixture being transferred calculated by the following Equation 1 to 0.140 kPa or more by controlling a transfer rate while transferring the monomer mixture to a polymerization reactor
Implementation Method 3
drying, pulverizing and classifying the hydrogel polymer to form a base resin powder
Implementation Method 4
further cross-linking a surface of the base resin powder in the presence of a surface cross-linking agent to form a surface cross-linked layer
Data Source
AI summary
The present disclosure relates to a preparation method of a super absorbent polymer capable of preparing a super absorbent polymer exhibiting an improved absorption rate while reducing an amount of a blowing agent used. The preparation method of a super absorbent polymer includes: preparing a monomer mixture including a water-soluble ethylene-based unsaturated monomer having at least partially neutralized acidic groups and an internal cross-linking agent; adjusting a dynamic pressure applied to the monomer mixture being transferred to 140 Pa or more by controlling a transfer rate while transferring the monomer mixture to a polymerization reactor; cross-linking and polymerizing the monomer mixture transferred to the polymerization reactor to form a hydrogel polymer; drying, pulverizing and classifying the hydrogel polymer to form a base resin powder; and further cross-linking a surface of the base resin powder in the presence of a surface cross-linking agent to form a surface cross-linked layer.