Liquid Lignin Composition Urea Viscosity Reduction

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Solution Overview

Problem

Existing liquid lignin compositions face challenges with high viscosity when lignin content exceeds 25 wt-% and water content is below 60 wt-%, making them unsuitable for high-solid-content resin applications such as laminates and fiberboards.

Innovation Solution

Incorporating 1-30% urea into the liquid lignin composition in an alkali solution reduces water content and viscosity, allowing for a higher lignin content while maintaining low viscosity, thus addressing the limitations of existing compositions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lignin content is increased above 25 wt-% and water content is reduced below 60 wt-%, then the solid content of the resin is improved, but the viscosity becomes too high for certain applications

Engineering Contradiction:
Improvesolid contentVSAvoidviscosity
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

Urea acts as a mediator substance that facilitates the dissolution of lignin in the alkali solution while maintaining low viscosity. It forms a complex with lignin that prevents excessive molecular association, thereby enabling high solid content (up to 65% or more) without the viscosity becoming unmanageably high. This intermediary substance bridges the gap between high concentration requirements and fluidity needs.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical composition parameters by introducing urea at concentrations of 1-30 wt-% into the system. This parameter change fundamentally alters the solution properties, allowing the lignin-alkali-urea complex to maintain low viscosity even at high lignin concentrations, thereby resolving the contradiction between solid content and viscosity.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If lignin is used as powder with low moisture content (0-5%), then it can be easily handled, but it becomes dusty and creates respiratory hazards

Engineering Contradiction:
ImprovehandlingVSAvoiddust and respiratory hazards
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention changes the physical state parameter of lignin from solid powder to liquid solution form. By dissolving lignin in an alkali-urea solution, the material transitions from a dusty powder to a liquid composition that can be pumped and applied without generating respiratory hazards, while maintaining ease of handling through controlled viscosity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The alkali-urea solution serves as an intermediary medium that carries the lignin in a non-dusty form. This liquid vehicle allows lignin to be transported and applied quantitatively without the handling difficulties and health hazards associated with fine powders, while still enabling precise dosing through the liquid phase.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If lignin is used as powder with high moisture content (8-50%), then respiratory hazards are reduced, but it becomes sticky or clumpy and difficult to transfer in reliable and quantitative manner

Engineering Contradiction:
Improverespiratory hazardsVSAvoidtransfer reliability
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The invention optimizes the moisture content parameter by using a controlled amount of water in the alkali-urea solution (typically 40-80 wt-%). This controlled hydration prevents the stickiness and clumping issues of high-moisture powders while maintaining the material in a pumpable liquid state that ensures reliable and quantitative transfer.

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 addition of urea enables the creation of a liquid lignin composition with reduced water content and viscosity, facilitating the use of high-lignin-content resins in applications like laminates and fiberboards without the issues of high water content.

Implementation Method 1

Incorporating 1-30% urea into the liquid lignin composition in an alkali solution reduces water content and viscosity

Methodology Applied
Scientific EffectHydrogen bonding disruption:

Implementation Method 2

Lignin can also be utilized in liquid form in alkali solution in order to avoid lignin dust

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentUS12221545B2Liquid lignin composition comprising lignin, water, alkali and urea
Publication Date: 2025.02.11 STORA ENSO OYJ

AI summary

The present invention relates to a liquid lignin composition, particularly useful in the manufacture of resins for products such as insulation, laminates and engineered wood products such as oriented strand boards (OSB). The liquid lignin composition has a low viscosity even at low water content.