Water Absorbing Agent Polyamine Polymer Balance CRC SFC
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Solution Overview
Problem
Conventional water absorbing agents for sanitary materials like disposable diapers face challenges in achieving a balance between centrifugal retention capacity (CRC) and saline flow conductivity (SFC), leading to issues such as gel blocking and fluid leakage, especially under pressure.
Innovation Solution
A water absorbing agent comprising a water absorbing resin and a polyamine polymer with a hydroxyl group on its main chain, obtained by reacting aliphatic secondary amines and epihalohydrin, or ammonia and epihalohydrin, which enhances the balance between CRC and SFC, improving absorption speed and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of water absorbing resin in the water absorbent core is increased to increase absorbing amount, then the absorption capacity improves, but the gel blocking phenomenon occurs under load causing liquid permeability to decrease
Solution Approach 1:
The invention changes the chemical parameters of the water absorbing resin by specifying a particular molecular structure with carboxyl groups and controlling the crosslinking degree to be 10^-6 to 10^-3 (determined by 1H-NMR). This parameter optimization allows the resin to maintain both high absorption capacity and sufficient liquid permeability under load by adjusting the balance between hydrophilic groups and crosslinking density.
Solution Approach 2:
The invention creates a composite water absorbing resin system that combines specific monomers (acrylic acid, acrylamide, vinyl sulfonic acid) with controlled crosslinking agents. This composite structure integrates the advantages of different functional groups and crosslinking densities to achieve both high absorption capacity and maintained liquid permeability under physiological loads.
2Quantity of substance
If the water absorbing resin is allowed to swell freely to maximize absorption capacity, then the CRC improves, but the gel blocking occurs reducing the SFC
Solution Approach 1:
The invention optimizes the chemical composition parameters by specifying carboxyl group content and crosslinking degree within specific ranges. This controlled parameter adjustment enables the resin to achieve optimal swelling behavior that maximizes CRC while preventing excessive gelation that would reduce SFC, thereby balancing both absorption capacity and fluid conductivity.
Solution Approach 2:
The invention creates local structural variations within the water absorbing resin particles through controlled crosslinking. The crosslinking is distributed throughout the resin matrix at optimized density, creating regions of varying mesh sizes that allow both high water uptake (improving CRC) and maintained fluid pathways (preserving SFC) coexist within the same material.
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 solution provides a water absorbing agent with improved CRC and SFC, ensuring excellent fluid absorbing speed and safety for sanitary materials, reducing the risk of fluid leakage and gel blocking, even under pressure.
Implementation Method 1
a water absorbing agent containing a water absorbing resin and a polymer (B) being a polyamine polymer having a hydroxyl group on a main chain
Implementation Method 2
water absorbing characteristics, the water absorbing resin having improved water absorbing characteristics
Implementation Method 3
a crosslinked polymer of 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid
Implementation Method 4
gel strength of a swelling gel
Data Source
Figure 1~2
AI summary
The present invention provides a water absorbing agent that is excellent in a balance between a centrifugal retention capacity (CRC) and a saline flow conductivity (SFC), and a method for producing the water absorbing agent. The method for producing the water absorbing agent, the method comprising mixing (i) a water absorbing resin (A) and (ii) a polymer (B) being a polyamine polymer having a hydroxyl group on a main chain provides a water absorbing agent containing (i) the water absorbing resin (A) and (ii) the polymer (B) being a polyamine polymer having a hydroxyl group on a main chain.