Cellulose Nanofibril Paper Composite Binder-Free Bonding

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Solution Overview

Problem

Current methods fail to produce strong, stiff, board-like products solely from paper and cellulose nanofibers, as existing applications typically use nanocellulose fibers in combination with polymeric binders or at low volumes in high-value products.

Innovation Solution

A composite laminated paper product, Cellubound™, is created by homogeneously impregnating cellulose nanofibers into paper layers through impregnation, compression, and heat treatment, eliminating the need for additional binders and resulting in a substantially homogeneous, reinforced composite with orthotropic or anisotropic strength properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If nanocellulose fibers are used in combination with polymeric binders, then bonding strength is improved, but material complexity and environmental impact worsen

Engineering Contradiction:

Improvebonding strengthVSAvoidmaterial complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention extracts and removes the polymeric binder component from the composite system, demonstrating that nanocellulose fibers alone can provide sufficient bonding strength through their network formation and interfacial adhesion mechanisms, thereby simplifying the material composition while maintaining performance

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The nanocellulose fibers serve dual functions: as reinforcement elements and as self-bonding agents. The fibers create a self-supporting network structure that provides both mechanical strength and adhesive bonding between layers without requiring external polymeric binders

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If nanocellulose fibers are dried prior to use, then processing quality is improved, but energy consumption increases

Engineering Contradiction:

Improveprocessing qualityVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The invention changes the processing parameters by eliminating the drying step entirely, utilizing the inherent moisture content of the nanocellulose suspension to achieve proper bonding and processing outcomes, thereby significantly reducing energy consumption while maintaining product quality

Inventive Principle:

Principle #35Parameter changes

3Strength

If multiple paper layers are laminated together, then structural strength is improved, but layer definition and homogeneity worsen

Engineering Contradiction:

Improvestructural strengthVSAvoidlayer definition

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The invention merges multiple discrete paper layers into a unified homogeneous composite structure through the interpenetration and bonding of nanocellulose fiber networks that permeate across layer interfaces, creating a integrated material system where individual layer boundaries become indistinct while overall structural strength is enhanced

Inventive Principle:

Principle #5Merging (Combining)

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 produces a strong, lightweight, eco-friendly material with strength comparable to some plastic composites, suitable for various applications, including automotive and packaging industries, with 100% recyclability and biodegradability.

Implementation Method 1

The nanofibers are homogeneously impregnated into the paper via impregnation, compression, and heat treatment steps

Methodology Applied

Scientific EffectImpregnation: Absorption (physical)

Implementation Method 2

subjecting the layer stack to a pressure and heat treatment to compress and dry the layer stack into a composite product

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 3

subjecting the layer stack to a pressure and heat treatment to compress and dry the layer stack

Methodology Applied

Scientific EffectHeat treatment: Heating

Implementation Method 4

the CNF may be used without substantial drying, therefore realizing an energy savings... the nanocellulose fibers act as a binder to hold together other structural elements

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS10875284B2Composite products of paper and cellulose nanofibrils and process of making

Publication Date: 2020.12.29 UNIVERSITY OF MAINE

AI summary

Strong, light-weight composite laminates are made by impregnating layers of paper with a cellulose nanofiber (CNF) slurry, laying the coated papers up in a plurality of layers or stack, and subjecting the stack to pressure and heat for a period of time sufficient to cause the CNF to impregnate, reinforce, and bond the paper layers into a composite. The resulting composite has impressive mechanical strength and exhibits a substantially homogeneous composition throughout its depth. The composite should have good strength to weight properties, and be recyclable or compostable.