Lignocellulosic Material Partial Delignification and Filling

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Solution Overview

Problem

Current methods for enhancing the mechanical properties of lignocellulosic materials, such as wood, are complex, expensive, and slow, often resulting in the destruction of the material's internal architecture, which hinders the preservation of its native structure and mechanical strength.

Innovation Solution

A process involving partial delignification and filling with a stabilizing compound, where the lignocellulosic material is soaked to dissolve 40-85% of its lignin, washed to evacuate dissolved lignin, and then filled with a compound that forms a three-dimensional network with cellulose and lignin, maintaining the material's architecture and enhancing mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If high pressure is used to ensure deep impregnation of wood with monomer/polymer, then impregnation depth is improved, but processing time increases and equipment complexity increases

Engineering Contradiction:
Improveimpregnation depthVSAvoidprocessing time
Core Design Contradiction:
Volume of moving objectVSLoss of time

Solution Approach 1:

The patent changes the physical-chemical parameters of the impregnation process by using solvents with specific solubility parameters matched to lignin chemistry, operating at controlled temperatures and pressures that optimize solvent penetration without requiring excessive pressure. This allows deep impregnation while reducing processing time compared to conventional high-pressure methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a solvent as an intermediary substance that facilitates the removal of lignin and subsequent impregnation of monomer/polymer. The solvent acts as a mediator between the wood structure and the filling compound, enabling deep penetration through the wood matrix without requiring extreme pressure conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If total delignification is performed to extract all lignin, then filler material replacement is maximized, but wood internal structure is destroyed

Engineering Contradiction:
Improvelignin removal amountVSAvoidwood structure integrity
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies partial delignification rather than total delignification, removing only a portion of the lignin (typically 30-70% as specified in embodiments) to create sufficient space for filler material while preserving enough lignin to maintain the wood's internal architecture and structural integrity. This partial action resolves the contradiction between maximizing filler replacement and preserving structure.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent creates local modifications in the wood structure by selectively removing lignin from specific regions and pores while leaving other areas intact. This localized delignification allows filler material to be introduced into specific zones without compromising the overall structural framework of the wood.

Inventive Principle:
Principle #3Local quality

3Strength

If conventional impregnation methods are used to improve mechanical properties, then strength enhancement is achieved, but the process becomes complex and expensive

Engineering Contradiction:
Improvemechanical strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines multiple operations into a unified process: delignification, impregnation, and polymerization are integrated into a single treatment sequence using the same solvent system. This merging of operations simplifies the overall process compared to conventional methods that require separate treatment stages, reducing equipment complexity and processing cost while achieving strength enhancement.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite material structure by introducing synthetic polymer networks into the delignified wood matrix. The resulting wood-polymer composite combines the structural advantages of natural wood with the mechanical properties of synthetic polymers, achieving enhanced strength through a relatively simple impregnation and polymerization process.

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 process results in a composite material with improved mechanical, chemical, and optical properties, retaining the native structure's architecture while increasing resistance and durability, forming a densified structure with stronger molecular bonds.

Implementation Method 1

at least one step of soaking the lignocellulosic material structure with at least one fluid to partially dissolve the lignin present in the material

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

at least one step of washing the structure from step (1) with at least one organic fluid so as to remove the dissolved lignin from the soaking step (1)

Methodology Applied
Scientific EffectExtraction: Liquid-Liquid Extraction

Implementation Method 3

forming a densified structure with stronger molecular bonds

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3656520B1Method for partial delignification and filling of a lignocellulosic material, and composite material structure obtained by said method
Publication Date: 2023.11.01 SAS WOODOO
  • EP3656520B1 patent drawingFigure 1~3
  • EP3656520B1 patent drawingFigure 4
  • EP3656520B1 patent drawingFigure 5~6

AI summary

The invention relates to a process for treating lignocellulosic material, preferably wood, comprising the following steps: (1) soaking the material in an organic fluid to partially dissolve some of the lignin in the material; (2) washing with an organic fluid to remove the dissolved lignin; (3) filling with a filler compound; and (4) finishing, so as to obtain a composite material formed of a three-dimensional network of processed filler compound incorporated into a network of cellulose and lignin. The invention also relates to a composite material structure that can be obtained in this way, and any part comprising at least one such structure.