Water-absorbing Polymeric Particles with Surface Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing water-absorbing polymeric particles face challenges in achieving high Saline Flow Conductivity (SFC), Centrifuge Retention Capacity (CRC), and wicking ability (FHA) simultaneously, with prior methods often compromising one performance metric for another.
Innovation Solution
A process involving non-surface-crosslinked water-absorbing polymers treated with a postcrosslinker, a nitrogen-containing water-soluble polymer, and a hydrophobic polymer, followed by heat-treatment within a specific temperature range, to optimize particle properties for enhanced fluid transportation and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the degree of internal crosslinking is increased to improve Saline Flow Conductivity (SFC), then SFC is improved, but Centrifuge Retention Capacity (CRC) deteriorates
Solution Approach 1:
The patent applies surface crosslinking to create a hydrophobic outer layer on the particles, while maintaining the hydrophilic interior structure. This local differentiation allows the surface to provide flow conductivity benefits while the interior preserves absorption capacity, resolving the contradiction between SFC and CRC improvement.
Solution Approach 2:
The patent creates a composite structure with both hydrophobic (crosslinked surface) and hydrophilic (inner core) regions within the same particle. This composite architecture enables simultaneous optimization of both SFC and CRC by having different regions perform different functions.
2Reliability
If stronger postcrosslinking is applied to improve SFC, then SFC is improved, but absorption capacity deteriorates
Solution Approach 1:
The surface crosslinking creates a localized hydrophobic shell that improves flow conductivity without affecting the bulk absorption properties of the particle interior, thus resolving the contradiction between enhanced SFC and maintained absorption capacity.
3Reliability
If particle size is increased to improve SFC, then SFC is improved, but wicking ability deteriorates
Solution Approach 1:
The surface crosslinked shell provides the flow conductivity benefits associated with larger particles, while the maintained particle size (or smaller size in the interior) preserves the capillary wicking ability, resolving the contradiction between SFC and wicking performance.
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 process results in water-absorbing polymeric particles with improved SFC, CRC, and FHA, maintaining a white color and odor neutrality, even under hot and humid conditions, suitable for ultrathin hygiene articles.
Implementation Method 1
heat-treating the particles thus obtained at a temperature in the range from 120°C to 300 °C
Implementation Method 2
high wicking ability (FHA = Fixed Height Absorption)
Implementation Method 3
water-absorbing polymers are in particular polymers of (co)polymerized hydrophilic monomers... that are swellable in aqueous fluids
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a water absorbing material obtainable by a process comprising the steps of bringing particles of a non surface-crosslinked water-absorbing polymer in contact with a) at least one postcrosslinker, b)10-1000 ppm, based on the non surface-crosslinked water-absorbing polymer, of at least one Nitrogen-containing water-soluble polymer of which the Nitrogen can be protonated, and c)at least one hydrophobic polymer and heat-treating the particles thus obtained at a temperature in the range from 120°C to 300°C and a method for the production thereof.