Porous Polymer Structure for Absorbent Articles

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Solution Overview

Problem

Existing hygiene absorbent products, such as diapers and sanitary napkins, face challenges in accessing small pores effectively when exposed to bodily fluids and in controlling the flow and distribution of body liquids, which affects their absorbent capacity and efficiency.

Innovation Solution

A porous polymer-based structure is created using a process involving the deposition and photopolymerization of an emulsion with a predetermined 3D model, resulting in a monolithic structure with three types of pores, which enhances access to small pores and controls fluid flow, integrated into absorbent articles with a liquid-pervious cover sheet and backsheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional polymeric foams with open-celled structures are used, then liquid-storage capacity is improved, but access to small pores is insufficient when exposed to bodily fluids

Engineering Contradiction:
Improveliquid-storage capacityVSAvoidaccess to small pores
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The foam structure is segmented into multiple pore size categories (small pores, medium pores, large pores) that are hierarchically organized. This segmentation allows different pore sizes to serve different functions: small pores provide high liquid-storage capacity while large pores facilitate fluid access and distribution throughout the structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the foam structure have different pore size characteristics. The structure incorporates zones with varying pore densities and sizes, allowing local optimization where small pores are concentrated for absorption while interconnected larger pores provide access pathways throughout the material.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If conventional foam structures are used, then absorbent capacity is improved, but control over fluid flow and direction is insufficient

Engineering Contradiction:
Improveabsorbent capacityVSAvoidcontrol over fluid flow
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The foam is segmented into functional zones with different pore size distributions. Upper regions may have smaller pores for initial absorption while lower regions have larger pores for distribution, creating controlled flow pathways that guide fluid through the absorbent article in a predetermined direction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The foam structure incorporates three-dimensional interconnected pore networks that extend throughout the material volume. This 3D architecture provides multiple flow pathways and allows control over fluid distribution in multiple directions, enabling precise control over fluid flow patterns within the absorbent article.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 structure improves absorbent capacity and fluid distribution by providing better access to small pores and precise control over fluid flow, leading to enhanced performance in absorbent articles.

Implementation Method 1

depositing and photopolymerizing, layer-by-layer in accordance with a predetermined 3D model, an emulsion comprising an external continuous phase surrounding droplets of an internal phase, the external phase comprising one or more photopolymerizable monomers and/or oligomers and a photopolymerization initiator

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11197784B2Absorbent disposable article comprising a porous polymer-based structure
Publication Date: 2021.12.14 ESSITY HYGIENE & HEALTH AB

AI summary

An absorbent disposable article, such as a diaper, panty diaper, panty liner, sanitary napkin or incontinence device is disclosed. The article has a porous polymer-based structure obtainable by a process of: (a) depositing and photopolymerizing, layer-by-layer in accordance with a predetermined 3D model, an emulsion having an external continuous phase surrounding droplets of an internal phase having has one or more photopolymerizable monomers and/or oligomers and a photopolymerization initiator; and (b) removing the internal phase from the continuous polymer phase formed from the one or more photopolymerizable monomers and/or oligomers. The process produces a monolithic porous structure having three types of pores: (i) pores resulting from the location from which the internal phase was removed, (ii) pores interconnecting the pores according to (i), and (iii) pores as predetermined by the 3D model. The invention also relates to a method of making the article.