Cold Press Molded Body With Adjusted Volume Resistivity

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Solution Overview

Problem

Existing composite materials with carbon and glass fibers face issues with fastening stability and springback during molding, particularly due to the lack of examination of fiber ratios in flowing regions, leading to insufficient fastening strength and stability.

Innovation Solution

A cold press molded body is developed using discontinuous carbon and glass fibers with specific weight average fiber lengths and volume ratios, where the volume resistivity in the flowing region is adjusted by controlling the volume of carbon and glass fibers, and a metal bolt is inserted into an insertion hole to enhance fastening stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a glass fiber-reinforced resin base material is used as an intermediate layer for laminating molded products with complicated shapes, then the adaptability to complicated shapes is improved, but the fastening stability is insufficient

Engineering Contradiction:
Improveadaptability to complicated shapesVSAvoidfastening stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating distinct flowing regions with different material compositions. The end regions (flowing regions) are specifically designed with a higher volume ratio of carbon fiber-containing material A to glass fiber-containing material B (Va flow /Vb flow < 0.5), while other regions may have different compositions. This local differentiation ensures that the end regions have optimized electrical properties for fastening stability while other regions maintain structural integrity and shape adaptability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by controlling the volume ratio of materials in different regions. Specifically, the volume ratio Va/Vb and the flowing region ratio Va flow /Vb flow are adjusted to optimize both shape adaptability and fastening stability. By changing the material composition parameters in the flowing regions, the electrical conductivity and fastening properties are improved without compromising the overall structural adaptability to complicated shapes.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If carbon fiber and thermoplastic resin are put into a carding machine for defibration and mixing, then the mixing uniformity is improved, but the fluidity of the carbon fiber resin layer deteriorates

Engineering Contradiction:
Improvemixing uniformityVSAvoidfluidity of carbon fiber resin layer
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the composite material into two separate materials: material A containing carbon fiber and thermoplastic resin, and material B containing glass fiber and thermoplastic resin. These materials are then laminated in a specific sequence and arranged in specific regions. This segmentation approach maintains the mixing uniformity of each individual material while preserving the fluidity of the carbon fiber resin layer, as material A is not subjected to excessive defibration that would compromise its fluidity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes composite materials by combining material A (carbon fiber-reinforced thermoplastic resin) and material B (glass fiber-reinforced thermoplastic resin) in a laminated structure. This composite approach allows each material to maintain its optimal properties: material A retains its fluidity and electrical conductivity, while material B provides structural support. The lamination creates a multi-functional composite that achieves both mixing uniformity and fluidity.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If the volume ratio of carbon fiber to glass fiber in the flowing region is not examined, then the manufacturing process is simple, but the fastening strength is insufficient

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidfastening strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies parameter changes by establishing specific volume ratio parameters for the flowing regions: Va/Vb < 2.0 and Va flow /Vb flow < 0.5, where Va is the volume of material A, Vb is the volume of material B, Va flow is the volume of material A in the flowing region, and Vb flow is the volume of material B in the flowing region. These parameter specifications ensure adequate fastening strength while maintaining a relatively simple manufacturing process through cold press molding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the material composition in flowing regions versus other regions. The flowing regions (end regions) are specifically designed with a higher concentration of material A (carbon fiber-containing) to provide the necessary fastening strength and electrical properties. This local optimization of material distribution ensures fastening strength without requiring complex manufacturing processes throughout the entire molded body.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4098438B1Cold press molded body containing carbon fiber and glass fiber, and manufacturing method thereof
Publication Date: 2024.03.13 TEIJIN LTD
  • EP4098438B1 patent drawingFigure 1
  • EP4098438B1 patent drawingFigure 2
  • EP4098438B1 patent drawingFigure 3A

AI summary

Provided is a cold press molded body having excellent bonding strength and bonding stability as well due to the use of a discontinuous carbon fiber and a discontinuous glass fiber for adjusting the volume, preferably the volume resistivity, of an end region (flow region).