Lignocellulosic Fiber Heat Treatment for Automotive Composite Odor Reduction

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Solution Overview

Problem

Composite materials based on natural lignocellulosic fibers used in automotive interiors face challenges with odor and volatile organic compound (VOC) emissions, as well as viscosity issues that hinder their injectability for manufacturing large parts, failing to meet automotive specifications.

Innovation Solution

A method involving heat treatment of lignocellulosic fibers at 130 to 320°C in an oxygen-deficient atmosphere with water vapor, followed by mixing with a thermoplastic polymer melt, reduces odor and VOC emissions and improves injectability, enabling the production of parts with enhanced thermomechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If natural lignocellulosic fibers are used in composite materials for automotive interiors, then the materials offer natural fiber benefits, but they emit odors and VOC that fail to meet automotive specifications

Engineering Contradiction:

Improvenatural fiber applicationVSAvoidodor and VOC emissions

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary heat treatment to the natural lignocellulosic fibers before composite material fabrication. The fibers are heated at 130-320°C in an oxygen-deficient atmosphere with water vapor to pre-remove volatile organic compounds and reduce odor emissions, ensuring the final composite material meets automotive specifications

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an oxygen-deficient atmosphere during heat treatment to prevent combustion of the natural fibers while effectively removing VOCs. This controlled inert environment allows thermal degradation of harmful volatiles without causing fiber damage or unwanted oxidation reactions

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Adaptability or versatility

If natural lignocellulosic fibers are used in composite materials, then the materials offer natural fiber properties, but they are too viscous to be injected for making large parts

Engineering Contradiction:

Improvenatural fiber composite propertiesVSAvoidinjectability for large parts

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent changes the thermal and rheological parameters of natural lignocellulosic fibers through heat treatment at 130-320°C with water vapor. This treatment modifies the fiber structure to reduce melt viscosity and improve flow characteristics, enabling successful injection molding of large automotive parts

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If heat treatment is applied to reduce odor and VOC emissions, then emissions are reduced, but the treatment conditions must be optimized to avoid fiber degradation

Engineering Contradiction:

Improveodor and VOC emissionsVSAvoidfiber structural integrity

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent employs an oxygen-deficient atmosphere during heat treatment to create a protective environment that prevents fiber combustion and oxidative degradation. This allows effective VOC removal through thermal treatment while maintaining fiber structural integrity and composite material reliability

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent utilizes phase transition of water to vapor during heat treatment. The water vapor atmosphere facilitates VOC removal through steam stripping while the controlled thermal conditions ensure fibers undergo beneficial structural changes without degradation

Inventive Principle:

Principle #36Phase transitions

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 treated composite material exhibits reduced odor and VOC emissions, improved injectability, and meets automotive specifications for parts like dashboards and door panels, with enhanced rigidity, shock resistance, and thermal resistance.

Implementation Method 1

at least partially eliminate the water, the odorous products and the VOC (methanol, acetic acid, furfural, etc.) present in the natural lignocellulosic fibers

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

partially degrade the hemicellulose and the lignin of the natural lignocellulosic fibers which hold together the bundles of fibers

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 3

the oxygen-deficient atmosphere would prevent the combustion of fibers

Methodology Applied

Scientific EffectCombustion prevention: Combustion

Data Source

PatentUS11780975B2Method for preparing a composite material made from natural lignocellulosic fibers having improved rheological properties and reduced emissions of odors and volatile organic compounds

Publication Date: 2023.10.10 FAURECIA INTERIEUR IND

AI summary

A method for preparing a composite material that includes the steps of: (i) heat treating natural lignocellulosic fibers at a temperature of 130 to 320° C. for 2 minutes to 24 hours in an atmosphere oxygen-deficient in and in the presence of water vapor, and (ii) mixing the heat treated natural lignocellulosic fibers with at least one thermoplastic polymer in the molten state and whose melting point is less than or equal to 230° C. The method is useful for producing vehicle parts from a composite material having natural lignocellulosic fibers with reduced volatile organic compound odor emissions.