Polyacrylate Super-Absorbent Polymer Moisture Control
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Solution Overview
Problem
Conventional methods for producing polyacrylic acid (salt)-based water absorbent resins face challenges in achieving stable and continuous large-scale production while maintaining high moisture content and physical properties, often resulting in fine powder generation and damage during transportation and processing.
Innovation Solution
The method involves adding a surface crosslinking agent to the water absorbent resin powder, followed by a reaction step, and then adding an aqueous liquid during or after the reaction, with controlled atmospheric dew point and temperature conditions to achieve a moisture content of 6-15% and improved anti-damage properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface crosslinking is performed to improve physical properties and reduce fine powder generation, then anti-damage property is improved, but moisture content decreases and production stability deteriorates
Solution Approach 1:
The patent changes the parameter of atmospheric dew point from conventional low values to specifically 20°C or higher, which fundamentally alters the moisture control mechanism during surface crosslinking. This parameter change allows the resin to maintain 6-15% moisture content while undergoing crosslinking, resolving the contradiction between improving anti-damage properties and controlling moisture content.
2Strength
If conventional surface crosslinking methods are used to improve physical properties, then gel strength and water absorption capacity are improved, but fine powder is generated during transportation and processing
Solution Approach 1:
By changing the atmospheric dew point parameter to 20°C or higher during surface crosslinking, the patent achieves optimal moisture content (6-15%) that prevents resin particle embrittlement. This resolves the contradiction by maintaining sufficient moisture to prevent fine powder generation while still achieving the desired gel strength through crosslinking.
3Quantity of substance
If moisture content is increased to improve water absorption capacity, then CRC and AAP are improved, but production stability and continuous manufacturing capability deteriorate
Solution Approach 1:
The patent establishes a feedback control system where the atmospheric dew point is monitored and controlled to maintain resin moisture content within the 6-15% range during continuous production. This feedback mechanism resolves the contradiction by automatically adjusting process conditions to maintain optimal moisture levels for both water absorption capacity and production stability.
4Reliability
If aqueous liquid is added during surface crosslinking to maintain moisture content, then anti-damage property is improved, but process complexity increases
Solution Approach 1:
The patent enables the resin to self-regulate its moisture content through controlled atmospheric conditions (dew point ≥20°C) during surface crosslinking, without requiring complex external moisture injection systems. The resin naturally maintains 6-15% moisture content through the controlled atmosphere, simplifying the process while improving anti-damage properties.
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 simplifies the process, reduces fine powder generation, and enhances the anti-damage properties of the water absorbent resin, enabling stable high-moisture content production suitable for large-scale industrial applications.
Implementation Method 1
adding an aqueous liquid during or after the reaction, with controlled atmospheric dew point and temperature conditions to achieve a moisture content of 6-15%
Implementation Method 2
adding a surface crosslinking agent to the water absorbent resin powder, followed by a reaction step
Data Source
AI summary
As a method for producing a polyacrylic acid (salt)-based water absorbent resin particle which less generates fine powder and has an excellent impact resistance and a high moisture content even in a case where the polyacrylic acid (salt)-based water absorbent resin particle is produced on a large scale, employed is a production method including the steps of: (a) adding a surface crosslinking agent solution to water absorbent resin powder to obtain a mixture; (b) reacting the mixture; and, thereafter (c) adding an aqueous liquid to at least one selected from the group consisting of (i) the water absorbent resin powder during the step (b) and (ii) the water absorbent resin powder after the step (b), an atmospheric dew point being not lower than 20°C in the step (c), and a temperature of the water absorbent resin powder being higher than the atmospheric dew point in the step (c).