Foam Formed Cellulosic Composite Web Production

Solution Overview

Problem

Existing methods for producing high-strength cellulosic composite structures face challenges such as fibre damage during processing, high water content requirements, and limited compatibility with conventional heat-moulding techniques, particularly with high cellulose content materials like lignin-based composites.

Innovation Solution

The process involves foam forming to create porous thermoformable webs from cellulosic fibres and thermoplastic materials, which minimizes fibre degradation and allows for high fibre content usage, enabling compression moulding into high-strength structures with the optional use of covalent cross-linking agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional injection moulding or extrusion is used to process composites with high cellulose content, then the manufacturing process is straightforward, but fibre damage occurs and product performance degrades

Engineering Contradiction:

Improveease of processingVSAvoidproduct performance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The invention changes the processing parameters by using compression moulding instead of injection moulding or extrusion. This alternative processing method applies different physical conditions (compression force, temperature, time) that are gentler on cellulose fibres, preventing fibre damage while still achieving successful manufacturing of high-strength composite products

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If lignin is used as a thermoplastic component in composites, then renewable materials are utilized, but the low molecular weight of lignin causes high viscosity and processing difficulties

Engineering Contradiction:

Improveuse of renewable materialsVSAvoidprocessability

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention changes the processing parameters by employing compression moulding with specific temperature and pressure conditions that are suitable for high-viscosity lignin-based composites. This allows the renewable lignin material to be successfully processed despite its inherently high viscosity caused by low molecular weight

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces porosity into the composite structure through the compression moulding process. The porous structure reduces the overall density and can facilitate easier processing of the viscous lignin-based composite material while maintaining structural integrity

Inventive Principle:

Principle #31Porous materials

3Ease of manufacture

If wet-forming techniques are used to mould cellulosic composites, then high water content is required, but this results in high energy consumption during drying

Engineering Contradiction:

ImprovemouldabilityVSAvoidenergy consumption

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention changes the processing parameters by using compression moulding with controlled moisture content instead of wet-forming techniques. This approach requires significantly less water and consequently reduces the energy consumption associated with the drying process, while still achieving successful moulding of cellulosic composite structures

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If wet-formed structures are produced with high water content, then moulding is easier, but the resulting structure is relatively dense with limited compression mouldability

Engineering Contradiction:

Improvemoulding easeVSAvoidcompression mouldability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The invention introduces porosity into the composite structure through the compression moulding process. The porous structure reduces the overall density and can facilitate easier processing of the viscous lignin-based composite material while maintaining structural integrity

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The invention changes the processing parameters by using compression moulding with controlled moisture content instead of wet-forming techniques. This approach requires significantly less water and consequently reduces the energy consumption associated with the drying process, while still achieving successful moulding of cellulosic composite structures

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

This method produces high-strength, lightweight composite structures with reduced water consumption and processing costs, enabling the use of renewable materials like lignin and allowing for scalable production of versatile products.

Implementation Method 1

a mixture is foam formed into a composite foam

Methodology Applied

Scientific EffectFoam forming: Foam

Implementation Method 2

applying it on a wire and optionally drying it to obtain a porous pre-form web

Methodology Applied

Scientific EffectDrying: Desiccation

Implementation Method 3

The web is compression moulded into the desired shape

Methodology Applied

Scientific EffectCompression moulding: Compression

Data Source

PatentEP3055350B1Production of high performance thermoplastic composites

Publication Date: 2021.04.14 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY

AI summary

The present invention concerns a process for producing a thermoformable porous web using a mixture of cellulosic fibres and one or more thermoplastic materials, particularly by foam forming said mixture into a composite foam, and applying the foam into one or more layers on a support to obtain a porous pre-form web. The thus produced porous composite web can be further processed by compression moulding to give a rigid high-strength composite structure, which is suitable for use in producing, e.g. panels or plates, packages or hygiene products, insulators or filters, or printed intelligence, electronics or microcellulose products.