Flexible Straw Fiberboard Using Thermoplastic Elastomer Binder

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Solution Overview

Problem

Current fiberboards, particularly those using agro-fibers and thermoset resins, pose health and environmental risks due to formaldehyde and isocyanate emissions, and lack recyclability and compostability, while wood-based composites face resource availability issues and require additional additives for flame retardancy.

Innovation Solution

A flexible high-density fiberboard composed of 80-90% straw fibers and 10-20% vinyl acetate-ethylene-vinyl ester copolymer thermoplastic elastomer, with optional additives, that is free from formaldehyde and isocyanates, using a dry process without chemical modification of straw fibers, enabling recyclability and compostability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermoset resins (urea-formaldehyde or phenol-formaldehyde) are used to bond agro-fibers in fiberboards, then the binding strength and structural integrity are improved, but formaldehyde emissions occur causing health and environmental problems

Engineering Contradiction:
Improvebinding strengthVSAvoidformaldehyde emissions
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful formaldehyde component from the binder system by replacing thermoset resins with thermoplastic binder granules containing no formaldehyde, thereby eliminating the source of harmful emissions while maintaining the fiberboard structure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters of the binder from formaldehyde-based thermoset resins to thermoplastic polymers with specific properties (melting point, molecular weight), fundamentally altering the binding mechanism from chemical crosslinking to thermal fusion

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If isocyanate-based resins (MDI) are used as alternative binders, then formaldehyde emissions are reduced, but cancer risk increases leading to EU classification as category 3 carcinogen

Engineering Contradiction:
Improveformaldehyde emissionsVSAvoidcancer risk
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes isocyanate compounds from the binder system, replacing them with thermoplastic polymers that contain no isocyanate groups, thereby eliminating the carcinogenic hazard while maintaining binding functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses conventional thermoplastic binder granules that are safe, non-carcinogenic, and can be processed through standard plastic industry machinery, replacing specialized hazardous resins with more benign materials

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

3Adaptability or versatility

If wood-based composites are used instead of agro-fibers, then resource availability and renewability are improved, but additional additives are required for flame retardancy increasing complexity

Engineering Contradiction:
Improveresource availabilityVSAvoidadditive requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies a self-service approach where the agro-fiber material itself provides inherent flame-retardant properties through its natural composition, eliminating the need for additional flame-retardant additives and simplifying the overall formulation

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If classic fiberboard manufacturing methods are used, then production experience and infrastructure are utilized, but recyclability and compostability are lost affecting end-of-life options

Engineering Contradiction:
Improvemanufacturing experienceVSAvoidrecyclability
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The invention enables discarding of the fiberboard at end-of-life with full recovery of value through composting, as the thermoplastic binder and agro-fiber components can be biologically degraded and returned to the ecosystem, creating a circular economy model

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent creates a composite material system combining agro-fibers with thermoplastic binder granules that maintains processability through conventional machinery while achieving new end-of-life properties through the specific selection of biodegradable components

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 solution minimizes health risks and environmental impact by eliminating toxic emissions, providing recyclable and compostable options, and enabling flexible, cost-effective, and sustainable production for various architectural applications.

Implementation Method 1

a flexible high-density fiberboard... which comprises straw fibers and a thermoplastic elastomer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

extruding the obtained mixture at a temperature such that the thermoplastic elastomer is in a molten state

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2965882B1Flexible high-density fiberboard and method for manufacturing the same
Publication Date: 2018.02.28 UNIVERSITAT STUTTGART

AI summary

The present invention provides a flexible high-density fiberboard which is essentially free of formaldehyde and isocyanates and comprises 70 to 90 % by weight of straw fibers, and 30 to 10 % by weight of a thermoplastic elastomer and one or more optional additive(s). Furthermore, the present invention provides a method for manufacturing such a flexible high-density fiberboard comprising the steps of providing straw fibers, providing a thermoplastic elastomer in powder form, optionally providing one or more additive(s), dry mixing the straw fibers, the thermoplastic elastomer powder and optionally the one or more additive(s), such that a mixture comprising 70 to 90 % by weight of the straw fibers, and 30 to 10 % by weight of the thermoplastic elastomer and one or more of the optional additive(s) is obtained, extruding the obtained mixture at a temperature such that the thermoplastic elastomer powder is in a molten state, and pressing the extruded mixture.