Fluid-absorbent core with composite polymer particles

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Solution Overview

Problem

Current ultrathin fluid-absorbent products face deficiencies in fluid acquisition, leakage, and rewet properties, which are exacerbated by the need for thicker acquisition-distribution layers that contradict the trend towards thinner absorbent articles, particularly in adult and baby diapers.

Innovation Solution

A fluid-absorbent core comprising two layers, with the upper layer containing a mixture of water-absorbent polymer particles G and H, where G is agglomerated using a specific binder and solvent solution, and the lower layer having high CRC and vortex values, optimizing fluid storage and absorption without increasing thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the proportion of cellulose fibers is lowered to produce thin disposable diapers, then the thickness is reduced, but the fluid acquisition, leakage and rewet properties deteriorate

Engineering Contradiction:
ImprovethicknessVSAvoidfluid acquisition, leakage and rewet properties
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent uses composite water-absorbent polymer particles comprising a porous core made of first polymer particles and a shell made of second polymer particles with different absorption characteristics. This composite structure enables thin diaper design while maintaining fluid acquisition, leakage, and rewet properties through the synergistic effects of the two polymer types.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention creates particles with non-uniform structure where the core and shell have different properties - the porous core provides rapid fluid acquisition while the shell controls rewet characteristics. This local differentiation of material properties within each particle allows simultaneous optimization of multiple performance parameters in a thin configuration.

Inventive Principle:
Principle #3Local quality

2Reliability

If thicker acquisition-distribution layers are used to prevent leakage and wet feeling, then the leakage and rewet properties improve, but the thickness increases

Engineering Contradiction:
Improveleakage and rewet propertiesVSAvoidthickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The composite particles with dual polymer structure provide enhanced fluid handling capabilities within reduced thickness. The first polymer in the core excels at rapid absorption while the second polymer in the shell provides controlled release, eliminating the need for thicker acquisition-distribution layers.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the physical and chemical parameters of the water-absorbent particles by creating a bimodal particle population with different pore structures, polymer types, and absorption kinetics. This parameter optimization allows thin design while maintaining leakage and rewet protection.

Inventive Principle:
Principle #35Parameter changes

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 enhances fluid acquisition, storage capacity, and rewet performance, preventing leakage while maintaining a thin profile, thus addressing the limitations of existing ultrathin products.

Implementation Method 1

a water absorbent mixture comprising at least 10% by weight of a first type of water-absorbent polymer particles, water-absorbent polymer particles G, with a vortex of less than 30s and at least 50% by weight of a second type of water-absorbent polymer particles, water-absorbent polymer particles H, with a CRC of at least 25 g/g

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

water-absorbent polymer particles G, with a vortex of less than 30s and at least 50% by weight of a second type of water-absorbent polymer particles, water-absorbent polymer particles H, with a CRC of at least 25 g/g

Methodology Applied
Scientific EffectOsmosis: Osmosis

Implementation Method 3

by using a solution or suspension comprising a) 0,04 to 1,2 % by weight water-soluble or water-dispersible polymeric binders or a mixture thereof, based on the water-absorbent polymer particles, b) 20 to 70% by weight of water based on the water-absorbent polymer particles

Methodology Applied
Scientific EffectSuspension: Suspension

Implementation Method 4

c) 5 to 20% by weight of a water-miscible organic solvent based on the water-absorbent polymer particles

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentEP3829511B1Fluid-absorbent core
Publication Date: 2024.02.14 BASF SE
  • EP3829511B1 patent drawingFigure 1~2
  • EP3829511B1 patent drawingFigure 3
  • EP3829511B1 patent drawing

AI summary

The present invention relates to a fluid-absorbent core (80) comprising at least two layers, an upper layer (91) and a lower layer (92), each layer comprising from 0 to 10% by weight fibrous material and from 90 to 100% by weight water-absorbent polymer particles, based on the sum of water-absorbent polymer particles and fibrous material, wherein within the upper layer (91) a water absorbent mixture comprising at least 10% by weight of a first type of water-absorbent polymer particles, water-absorbent polymer particles G, with a vortex of less than 30s and at least 50% by weight of a second type of water-absorbent polymer particles, water-absorbent polymer particles H, with a CRC of at least 25 g/g and a fluid-absorbent article comprising said fluid-absorbent core (80).