Transparent Fiber Composite Coating for Low-Expansion Flexibility

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Solution Overview

Problem

Conventional fiber composite materials, such as glass fiber-reinforced resins, become opaque under certain temperature and wavelength conditions due to refractive index variations, and the use of microfibrillated fibers with a matrix material reduces flexibility and increases thermal expansivity, making them unsuitable for various applications.

Innovation Solution

A highly transparent fiber composite material is created by coating a fiber assembly with nanoscale fibers (4-200 nm diameter) using a thin layer of organic, inorganic, or hybrid polymer materials, which suppresses light scattering and maintains the fiber's flexibility and low thermal expansivity, without filling the void spaces with additional materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If glass fiber-reinforced resins are used to achieve transparency, then transparency can be obtained under certain temperature conditions, but the material becomes opaque under different temperature conditions due to refractive index variations

Engineering Contradiction:
ImprovetransparencyVSAvoidtransparency stability under temperature variation
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention changes the refractive index parameter of the matrix resin to match that of the fiber (both set to 1.50), ensuring that transparency is maintained across different temperature conditions. This parameter matching eliminates the temperature-dependent transparency issues encountered in conventional glass fiber-reinforced resins.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If microfibrillated fiber material is impregnated with matrix material to achieve high transparency, then light scattering is suppressed, but the flexibility decreases and thermal expansivity increases

Engineering Contradiction:
ImprovetransparencyVSAvoidflexibility
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

The invention changes the refractive index parameter of the matrix resin to match that of the fiber (both set to 1.50), ensuring that transparency is maintained across different temperature conditions. This parameter matching eliminates the temperature-dependent transparency issues encountered in conventional glass fiber-reinforced resins.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If microfibrillated fiber material is impregnated with matrix material to achieve high transparency, then light scattering is suppressed, but the manufacturing process becomes complicated and time-consuming

Engineering Contradiction:
ImprovetransparencyVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The invention changes the refractive index parameter of the matrix resin to match that of the fiber (both set to 1.50), ensuring that transparency is maintained across different temperature conditions. This parameter matching eliminates the temperature-dependent transparency issues encountered in conventional glass fiber-reinforced resins.

Inventive Principle:
Principle #35Parameter changes

4Illumination intensity

If glass fiber-reinforced resins are used to achieve transparency, then transparency can be obtained at specific wavelengths, but the material becomes opaque in certain wavelength ranges due to refractive index differences

Engineering Contradiction:
ImprovetransparencyVSAvoidtransparency across wavelength range
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The invention changes the refractive index parameter of both the fiber and matrix resin to 1.50, creating a wavelength-independent transparency. This parameter matching eliminates the wavelength-dependent transparency issues encountered in conventional glass fiber-reinforced resins.

Inventive Principle:
Principle #35Parameter changes

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 results in a fiber composite with high transparency, reduced material usage, simplified manufacturing, and preserved fiber characteristics, suitable for applications in electronics, optics, and structural materials.

Implementation Method 1

coating a fiber assembly having fiber diameters less than wavelengths of visible light with a coating layer... scattering of visible light at the interfaces between the fibers and the matrix material in the void spaces is suppressed

Methodology Applied
Scientific EffectLight scattering suppression: Scattering

Data Source

PatentEP2042300B1Fiber composite material and process for producing the same
Publication Date: 2013.09.11 ROHM CO LTD
  • EP2042300B1 patent drawingFigure 1
  • EP2042300B1 patent drawingFigure 2(a)~2(b)
  • EP2042300B1 patent drawingFigure 3(a)~3(b)

AI summary

A highly transparent fiber composite material is provided that can be manufactured through a simplified process using reduced amounts of raw materials and that has high flexibility and low thermal expansivity and retains good functionality of the fiber material. The fiber composite material includes: a fiber assembly having an average fiber diameter of 4 to 200 nm and a 50 µm-thick visible light transmittance of 3% or more; and a coating layer that coats and smoothes the surface of the fiber assembly, wherein the fiber composite material has a 50 µm-thick visible light transmittance of 60% or more. With this fiber assembly, the scattering of light caused by the irregularities on the surface can be suppressed by coating the surface with the coating layer to smooth the surface, whereby a highly transparent fiber composite material can be obtained.