Densifying Hydrophilic Biomaterials Using Ionic Liquids

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Solution Overview

Problem

The widespread commercialization of surface-densified wood products is hindered by elastic spring-back and moisture-induced set-recovery, which existing methods struggle to effectively address.

Innovation Solution

A method involving the use of non-imidazolium-based ionic liquids, organic superbases, or Deep Eutectic Solvents to plasticize and densify hydrophilic polymeric biomaterials by softening with heat, applying pressure, and then reducing temperature and pressure, while incorporating these liquids to penetrate and break hydrogen bonds, facilitating controlled densification without residual hardening agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional heat and moisture softening is used, then the wood cells can be deformed, but elastic spring-back and set-recovery occur after compression

Engineering Contradiction:
ImprovedensificationVSAvoidspring-back and set-recovery
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies ionic liquids and Deep Eutectic Solvents to fundamentally change the plasticization mechanism from thermal-moisture based to chemical solvent based. These substances penetrate wood cells and disrupt hydrogen bonding networks, allowing deformation at lower temperatures and preventing spring-back through chemical modification of the polymer structure rather than just thermal softening.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The ionic liquids and DES act as intermediary substances that mediate between the compression force and the wood cell structure. These solvents temporarily replace the hydrogen bonding network with solvent-polymer interactions, enabling plastic deformation without the elastic recovery that occurs with conventional thermal softening alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If chemical modification or resin impregnation is used to eliminate set-recovery, then the problem is solved, but the process complexity and cost increase

Engineering Contradiction:
Improveset-recovery eliminationVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ionic liquids and Deep Eutectic Solvents serve multiple functions simultaneously: they plasticize the wood cells, enable densification, and chemically modify the polymer structure to prevent spring-back. This multi-functionality eliminates the need for separate chemical modification or resin impregnation steps, reducing process complexity while achieving the same reliability benefits.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If accurate volume definition for plasticization is required, then controlled densification is achieved, but the process precision requirements increase

Engineering Contradiction:
Improvevolume controlVSAvoiddepth control
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The ionic liquids and DES are applied to the wood surface before compression, allowing them to penetrate and plasticize the cell walls in advance. This preliminary chemical action creates a defined plasticized zone that responds uniformly to subsequent compression, making the process less sensitive to precise depth control measurements during the actual densification step.

Inventive Principle:
Principle #10Preliminary action

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 method significantly reduces elastic spring-back and set-recovery, increases hardness, and allows for cost-effective, scalable production with minimal environmental impact by recycling the plasticizing liquids, thus enhancing the properties of wood and wood-based materials.

Implementation Method 1

softening said surface of the hydrophilic polymeric biomaterial to be compressed by applying heat to increase the temperature of the hydrophilic polymeric biomaterial

Methodology Applied
Scientific EffectHeat: Heating

Implementation Method 2

compressing the hydrophilic polymeric biomaterial by applying an elevated pressure onto the softened surface

Methodology Applied
Scientific EffectPressure: Compression

Implementation Method 3

decreasing the temperature applied to the hydrophilic polymeric biomaterial

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 4

a plasticizing liquid is added to said surface of the hydrophilic polymeric biomaterial to be densified, before step b), such that said liquid penetrates said surface during step b)

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3972833B1Method of plasticizing and densifying hydrophilic polymeric biomaterials and hydrophilic polymeric biomaterials
Publication Date: 2025.09.10 NEYSES BENEDIKT MATTHIAS
  • EP3972833B1 patent drawingFigure 1~2
  • EP3972833B1 patent drawingFigure 3~4
  • EP3972833B1 patent drawingFigure 5a~6

AI summary

The present invention relates to a method of plasticizing and densifying hydrophilic polymeric biomaterial, said hydrophilic polymeric biomaterial having at least one surface, comprising the steps of softening the surface of the hydrophilic polymeric biomaterial to be compressed; compressing the hydrophilic polymeric biomaterial by applying an elevated pressure onto the softened surface of said hydrophilic polymeric biomaterial at an elevated temperature for a predetermined period of time; decreasing the temperature and thereafter the pressure applied to the hydrophilic polymeric biomaterial; wherein a plasticizing liquid is added to said surface of the hydrophilic polymeric biomaterial to be densified, the plasticizing liquid being a non-imidazolium-based ionic liquid (IL), an organic superbase or a Deep Eutectic Solvent (DES).