Dry-Formed Cellulose Molding Without Wet-Process Drying

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Solution Overview

Problem

Existing methods for manufacturing cellulose products face challenges such as the need for drying, formation of strong inter-fibre bonds, and the use of non-recyclable thermoplastics, which hinder the production of sustainable, recyclable, and mechanically strong cellulose-based packaging materials.

Innovation Solution

A dry forming process using air-laid cellulose fibres, heated and pressed at specific temperatures and pressures to create strong cellulose products, with optional additives for enhanced properties, allowing for recyclability and high mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If wet-forming techniques are used to manufacture cellulose products, then the material can be formed into three-dimensional shapes, but the process requires time and energy consuming drying steps

Engineering Contradiction:
Improvethree-dimensional shapeVSAvoiddrying time
Core Design Contradiction:
ShapeVSLoss of time

Solution Approach 1:

The patent extracts and removes the water removal step from the traditional wet-forming process by using air-laid dry cellulose fibres instead of water-based suspension, thereby eliminating the need for subsequent drying operations while still enabling three-dimensional shaping through compression and heating

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of starting with wet cellulose suspension and removing water (traditional approach), the patent inverts the process by starting with dry air-laid cellulose fibres and adding moisture control during compression, reversing the conventional sequence of operations to eliminate drying time

Inventive Principle:
Principle #13The other way round (Inversion)

2Shape

If wet-forming techniques are used to manufacture cellulose products, then the material can be formed into three-dimensional shapes, but the process is energy consuming due to drying requirements

Engineering Contradiction:
Improvethree-dimensional shapeVSAvoiddrying energy
Core Design Contradiction:
ShapeVSUse of energy by stationary object

Solution Approach 1:

The patent extracts and removes the water removal step from the traditional wet-forming process by using air-laid dry cellulose fibres instead of water-based suspension, thereby eliminating the need for subsequent drying operations while still enabling three-dimensional shaping through compression and heating

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental parameter of moisture content from high (wet-forming) to low (dry-forming), using air-laid fibres with controlled moisture levels that eliminate the need for energy-intensive drying while maintaining formability through compression and heating

Inventive Principle:
Principle #35Parameter changes

3Strength

If strong inter-fibre bonds are formed through hydrogen bonding, then the material gains structural integrity, but the flexibility of the material is restricted

Engineering Contradiction:
Improveinter-fibre bond strengthVSAvoidmaterial flexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent changes the bonding mechanism from hydrogen bonding (wet-forming) to heat-activated bonding (dry-forming), using elevated temperatures during compression to create strong bonds that maintain both structural integrity and flexibility by avoiding the rigid cross-linking characteristic of hydrogen bonds

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material principles by combining air-laid cellulose fibres with controlled moisture and heat treatment, creating a multi-phase structure that achieves both strength and flexibility through the synergistic effect of dry fibre mat and thermal bonding

Inventive Principle:
Principle #40Composite materials

4Shape

If thermoplastic materials are added to cellulose fibres to enable dry forming, then the material can be formed into three-dimensional shapes, but the recyclability and sustainable features are lost

Engineering Contradiction:
Improvethree-dimensional shapeVSAvoidrecyclability loss
Core Design Contradiction:
ShapeVSObject-generated harmful factors

Solution Approach 1:

The patent uses a minimal amount of water-soluble binder instead of thermoplastic additives, creating a biodegradable and recyclable product that can be disposed of or recycled without contamination from synthetic polymers, eliminating the harmful effects of non-recyclable material combinations

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the bonding mechanism from thermoplastic-based bonding to heat-activated cellulose bonding, using elevated temperatures during compression to create strong bonds without requiring synthetic polymer additives, thereby maintaining recyclability and sustainable features

Inventive Principle:
Principle #35Parameter changes

5Productivity

If modern lean production lines require in-line and on-demand manufacturing, then production efficiency is improved, but wet-forming processes are not preferred due to drying requirements

Engineering Contradiction:
Improveproduction efficiencyVSAvoiddrying time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent extracts and removes the water removal step from the traditional wet-forming process by using air-laid dry cellulose fibres instead of water-based suspension, thereby eliminating the need for subsequent drying operations and enabling continuous in-line production without time-consuming drying stages

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables continuous production by using air-laid dry fibres that can be continuously fed into compression and heating units without interruption for drying, maintaining continuous useful action throughout the manufacturing process and improving overall productivity

Inventive Principle:
Principle #20Continuity of useful 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 produces cellulose products with improved mechanical properties, recyclability, and reduced environmental impact, suitable for various shapes and applications, including packaging and protective inserts.

Implementation Method 1

a cellulose blank is dry formed in a dry forming unit, arranged in a forming mould, heated to a forming temperature and pressed in the forming mould

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

heated to a forming temperature and pressed in the forming mould with a forming pressure of at least of 1 MPa

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3974135B1Method for manufacturing a cellulose product, cellulose product forming apparatus and cellulose product
Publication Date: 2026.04.22 PULPAC AB
  • EP3974135B1 patent drawingFigure 1
  • EP3974135B1 patent drawingFigure 2a~2b
  • EP3974135B1 patent drawingFigure 3a~3b

AI summary

A method for manufacturing a cellulose product, comprising the steps: dry forming a cellulose blank in a dry forming unit; arranging the cellulose blank in a forming mould; heating the cellulose blank to a forming temperature in the range of 100°C to 200°C; and pressing the cellulose blank in the forming mould with a forming pressure of at least 1 MPa.