Plant Fiber-Reinforced Resin Interior Trim Fogging Prevention

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Solution Overview

Problem

Resin molded interior parts in vehicles, such as instrument panels, generate volatile acidic substances that cause fogging on glass windows due to the inability to neutralize these substances with alkaline aqueous solutions, leading to ineffective prevention of the fogging phenomenon.

Innovation Solution

A method involving mixing wood powder with alkaline substances, like calcium hydroxide, to induce a neutralization reaction, forming a plant fiber-reinforced resin that reduces volatile substances, which is then processed through kneading and heating to remove unneutralized acids, thereby preventing fogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an alkaline aqueous solution is used to treat resin molded interior parts, then the treatment process is simple, but the resin molded article cannot be impregnated with the aqueous solution and neutralization reaction cannot be induced

Engineering Contradiction:
Improvetreatment process simplicityVSAvoidneutralization effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the physical state of the alkaline substance from aqueous solution to powder form, and changes the processing method from surface treatment to high-shear mixing during kneading. This enables the alkaline substance to be uniformly dispersed and intimately contact the volatile acidic substances within the resin molded article, achieving effective neutralization that overcomes the impregnation problem of aqueous solutions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a powder alkaline substance as an intermediary that can be uniformly distributed throughout the resin molded article during the kneading process. This intermediary form allows the alkaline substance to reach and neutralize volatile acidic substances throughout the interior part, rather than only on the surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If wood powder is mixed with alkaline substances before kneading, then neutralization reaction is induced and volatile substances are reduced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvevolatile substance contentVSAvoidmixing process complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the mixing of wood powder and alkaline substances with the existing resin kneading process. By adding both materials to the kneading machine simultaneously and utilizing the high-shear mixing action during thermal melting, the patent achieves intimate contact and neutralization reaction without requiring separate mixing equipment or additional process steps.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the resin molded article is treated with alkaline substances, then volatile acidic substances may be neutralized, but the treatment must be applied before molding which limits process flexibility

Engineering Contradiction:
Improvefogging prevention effectivenessVSAvoidprocess timing flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies the alkaline substance to the wood powder before the molding process, during the kneading stage. This preliminary action ensures that the neutralization reaction occurs within the material itself before the final product is formed, guaranteeing fogging prevention effectiveness while allowing the treatment to be integrated into the standard molding workflow.

Inventive Principle:
Principle #10Preliminary 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 effectively reduces volatile substances in the resin, significantly preventing fogging on glass windows and improving reflectivity, even at high cabin temperatures, while also reducing odor components.

Implementation Method 1

the neutralization reaction between the volatile substances or aliphatic acids contained in the wood powder and the alkaline substances may be induced. Therefore, aliphatic acids contained in the wood powder may be changed to metal soap

Methodology Applied
Scientific EffectNeutralization reaction: Chemical Bonding

Implementation Method 2

in the heating step, the plant fiber-reinforced resin is heated at a temperature not less than a temperature at which volatile substances contained in the wood powder is volatilized and less than a temperature at which the resin is melted. Therefore, even when aliphatic acids contained in the wood powder remain unneutralized without neutralized by the alkaline substances, such aliphatic acids may be volatilized in the heating step so as to be removed

Methodology Applied
Scientific EffectVolatilization: Evaporation

Data Source

PatentEP3450484B1Method for producing interior trim
Publication Date: 2023.03.15 TOYOTA SHATAI KK
  • EP3450484B1 patent drawingFigure 1~2
  • EP3450484B1 patent drawingFigure 3
  • EP3450484B1 patent drawingFigure 4

AI summary

The present invention may include a mixing step for mixing a wood powder and alkaline substances, a kneading step for feeding a mixture of the wood powder and the alkaline substances and a resin into kneading machine and kneading the same in a condition in which the resin is thermally melted, and a molding step for forming an interior part using a plant fiber-reinforced resin obtained in the kneading step.