Fixed Carbon Fiber Bundle with Sizing Agent for Controlled Division

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Solution Overview

Problem

Existing methods for producing composite materials with carbon fibers face challenges in uniformly dividing carbon fiber bundles due to heat shrinkage and fuzz generation, leading to inconsistent physical properties and high processing stress, especially when attempting to produce narrow-width bundles.

Innovation Solution

A method involving a fixing agent that adheres to at least one side of the carbon fiber bundle, with a softening point between 60°C and 250°C, to stabilize the bundle's thickness and width during division, allowing for controlled division with reduced processing stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If heat-fusible yarn is supplied in a meandering shape to fill the surface of the carbon fiber bundle, then the carbon fiber bundle is maintained in a parallel state, but the bundle width becomes non-uniform due to heat shrinkage after melt solidification and fuzz is generated where the yarn is not supplied

Engineering Contradiction:
Improveparallel state of carbon fiber bundleVSAvoiduniformity of bundle width
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

A sizing agent containing polypropylene and epoxy-containing monomer is introduced as an intermediary substance to treat the carbon fiber bundle surface. This sizing agent provides uniform coverage without the heat shrinkage problems of heat-fusible yarn, while maintaining fiber parallelism and enabling clean division. The sizing agent acts as a mediator between the carbon fibers and the division process, preventing fuzz generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the average thickness of the carbon fiber bundle is made thin to enable division, then the bundle can be divided more easily, but the carbon fiber bundle may crack in the width direction at unintended places and cannot be divided to target width

Engineering Contradiction:
Improveease of divisionVSAvoidstable division without cracking
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The carbon fiber bundle is subjected to sizing treatment with polypropylene and epoxy-containing monomer before the division process. This preliminary action strengthens the bundle structure and controls its physical properties, enabling thin bundles to be divided cleanly without cracking or width deviation. The sizing agent prepares the bundle in advance to withstand the division process reliably.

Inventive Principle:
Principle #10Preliminary action

3Strength

If a publicly known unidirectional fiber-reinforced composite material is used as fixed carbon fiber bundle, then the bundle has high strength, but the dividing tear load exceeds 1.00 N making processing stress too large and apparatus size large

Engineering Contradiction:
Improvestrength of carbon fiber bundleVSAvoiddividing tear load
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The dividing tear load is reduced from exceeding 1.00 N to 0.01 N or more and 1.00 N or less through parameter changes in the sizing agent composition (polypropylene and epoxy-containing monomer) and treatment conditions. This parameter optimization maintains the strength of the carbon fiber bundle while enabling clean division with minimal processing stress and smaller apparatus size.

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 method enables stable division of carbon fiber bundles with controlled thickness and width, reducing fuzz generation and heat shrinkage issues, and facilitates the production of composite materials with improved mechanical properties.

Implementation Method 1

a fixing agent is made to adhere to a carbon fiber bundle after opening of the carbon fiber bundle; and the carbon fiber bundle is fixed by melting and solidifying the fixing agent

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the carbon fiber bundle is fixed by melting and solidifying the fixing agent

Methodology Applied
Scientific EffectMelting and solidification: Melting

Data Source

PatentEP3686331B1Fixed carbon fiber bundle and method for producing fixed carbon fiber bundle
Publication Date: 2021.10.20 TEIJIN LTD
  • EP3686331B1 patent drawingFigure 1
  • EP3686331B1 patent drawingFigure 2~3
  • EP3686331B1 patent drawing

AI summary

The present invention provides a fixed carbon fiber bundle to which a fixing agent is adhered, wherein the fixing agent adheres to an area comprising at least 50% of at least one side of a carbon fiber bundle, the average thickness of the fixed carbon fiber bundle is 180 µm or less, and the separated fiber tear load is 0.02 N to 1.00 N.