Self-Supporting Regenerated Cellulose Membrane for Skin Adhesion

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Solution Overview

Problem

A stable self-supporting thin membrane composed of cellulose with a thickness of several micrometers has not been obtained, as existing methods face challenges in separating a cellulose membrane from a porous support without damage.

Innovation Solution

A self-supporting membrane made of regenerated cellulose with a weight average molecular weight of 150,000 or more and a thickness between 20 nm and 1300 nm is developed, using an ionic liquid as a solvent to dissolve cellulose, allowing for the formation of a stable, flexible, and strong membrane that can be stuck to living organisms without the need for adhesives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a coating layer containing cellulose is formed on a porous support, then the membrane structure can be obtained, but it is difficult to separate the cellulose membrane from the porous support

Engineering Contradiction:
Improvemembrane formationVSAvoidmembrane separation
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The invention extracts and removes the porous support from the final product structure. Instead of keeping the support as part of the membrane system, the method produces a free-standing cellulose membrane that can be separated and used independently without the support substrate.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the membrane system into two independent parts: the porous support used during manufacturing and the final self-supporting cellulose membrane. This segmentation allows the membrane to be produced on a support and then separated as a distinct, functional component.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If cellulose is dissolved in traditional solvents, then the processing can be performed, but it is difficult to obtain high molecular weight cellulose solution

Engineering Contradiction:
Improvecellulose processingVSAvoidmolecular weight
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The invention changes the chemical parameters of the solvent system by using ionic liquids instead of traditional organic solvents. This parameter change enables the dissolution of high molecular weight cellulose while maintaining solution stability and processability, overcoming the limitations of conventional solvent systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a composite solvent system combining ionic liquids with traditional solvents or water. This composite approach leverages the unique properties of ionic liquids to dissolve cellulose effectively while preserving high molecular weight, achieving a balance between solubility and molecular weight retention.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the membrane thickness is reduced to achieve thin film properties, then the flexibility and comfort improve, but the structural integrity and self-supporting capability deteriorate

Engineering Contradiction:
Improveflexibility and comfortVSAvoidstructural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention creates a self-supporting thin film structure that maintains mechanical integrity at reduced thickness. The membrane achieves sufficient strength-to-thickness ratio through optimized cellulose molecular weight and cross-linking, enabling thin film applications without requiring additional support structures.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention uses cross-linked cellulose networks and optimized molecular weight distributions to enhance the mechanical properties of thin membranes. This composite approach at the molecular level provides the necessary structural integrity while maintaining the thin film morphology for flexibility and comfort.

Inventive Principle:
Principle #40Composite materials

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 resulting cellulose membrane is strong, flexible, and can be effectively stuck to skin or other surfaces for extended periods without causing discomfort or sweatiness, while maintaining its structural integrity and ability to retain cosmetic or medical components.

Implementation Method 1

cellulose is difficult to be solved because cellulose forms a hydrogen bond inside the molecule or between molecules... ionic liquid receive attention as a solvent capable of efficiently dissolving cellulose

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

a method of obtaining regenerated cellulose after dissolving cellulose in an acid aqueous solution or an alkali aqueous solution or an organic solvent containing a metal salt

Methodology Applied
Scientific EffectPhase separation: Phase Change

Data Source

PatentEP3542784B1Film to be adhered to living body and method for manufacturing same
Publication Date: 2024.03.06 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3542784B1 patent drawingFigure 1~2
  • EP3542784B1 patent drawingFigure 3~5
  • EP3542784B1 patent drawingFigure 6~7

AI summary

A cellulose membrane according to an embodiment of the present disclosure is a self-supporting cellulose membrane having a thickness of between 20 nm and 1300 nm, inclusive, composed of regenerated cellulose having a weight average molecular weight of 150,000 or more.