Sizing agent coated carbon fiber bundle, method for manufacturing same, prepreg, and carbon fiber reinforced composite material
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Solution Overview
Problem
Current carbon fiber reinforced composite materials face challenges in achieving high interfacial adhesion between carbon fibers and matrix resins, particularly in terms of processability, handleability, and flexibility, with existing sizing agents failing to enhance abrasion resistance and dynamic characteristics.
Innovation Solution
A sizing agent coated carbon fiber bundle is developed using a polyether-type aliphatic epoxy compound or a water-insoluble compound with a specific glass transition temperature, applied in a manner that ensures uniform attachment to both ends of the fiber bundle, enhancing adhesion and preventing fluffing during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sizing agent is applied to improve adhesion between carbon fiber and matrix resin, then interfacial adhesion is improved, but processability and handleability deteriorate due to increased stiffness and reduced flexibility
Solution Approach 1:
The patent applies different sizing agents to different regions of the carbon fiber bundle - a first sizing agent (e.g., polyamide resin) is applied to the surface for adhesion improvement, while a second sizing agent (e.g., polyurethane resin) is applied to the core for maintaining flexibility and processability. This regional differentiation resolves the contradiction between adhesion and processability.
Solution Approach 2:
The patent uses a composite sizing agent system combining multiple resin types (polyamide, polyurethane, epoxy, etc.) with complementary properties. The combination allows the sizing layer to simultaneously provide strong adhesion to the matrix resin while maintaining the necessary flexibility and processability for manufacturing operations.
2Reliability
If a sizing agent is applied to suppress fluffing during processing, then abrasion resistance is improved, but adhesion to matrix resin deteriorates due to excessive bundling properties
Solution Approach 1:
The patent differentiates the functional requirements of different sizing agent layers - the outer layer uses sizing agents optimized for abrasion resistance and fluff suppression, while the inner layer uses sizing agents optimized for adhesion to the matrix resin. This layered approach with differentiated properties resolves the contradiction between abrasion resistance and adhesion.
Solution Approach 2:
The patent applies sizing agents in a specific sequence before matrix resin impregnation - first applying a sizing agent that provides abrasion resistance, then applying another sizing agent that ensures adhesion. This preliminary sequencing of actions ensures both requirements are met without interference.
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 provides improved interfacial adhesion, abrasion resistance, and dynamic characteristics, ensuring high-quality carbon fiber reinforced composite materials with enhanced mechanical strength and processability.
Implementation Method 1
a method in which the carbon fiber is subjected to an oxidation treatment such as gas-phase oxidation or liquid-phase oxidation and thereby introducing oxygen-containing functional groups into the carbon fiber surface, has been performed
Implementation Method 2
a method in which the carbon fiber is subjected to an oxidation treatment such as gas-phase oxidation or liquid-phase oxidation and thereby introducing oxygen-containing functional groups into the carbon fiber surface
Implementation Method 3
application of a sizing agent to a carbon fiber bundle is used also for the purpose of suppressing fluffing due to single yarn breakage in processing process like sheet preparation such as prepreg and molding such as filament winding
Data Source
AI summary
Provided are a sizing agent coated carbon fiber bundle that has excellent mechanical characteristics when used as a carbon fiber reinforced composite material, as well as excellent ease of handling; a method for manufacturing the same; and a prepreg and carbon fiber reinforced composite material of excellent mechanical characteristics, employing the fiber bundle. The carbon fiber bundle is coated with a sizing agent that includes a polyether aliphatic epoxy compound having two or more epoxy groups per molecule and/or a polyol aliphatic epoxy compound or a non-water-soluble compound having a glass transition temperature of −100-50° C., wherein the sizing agent coated carbon fiber bundle is characterized in that the flatness ratio (width/thickness) of the carbon fiber bundle cross section is 10-150, and a two edge part/center part sizing agent deposition ratio, obtained by dividing the carbon fiber bundle in the width direction along the fiber direction into three equal parts by mass, and computing the ratio from the ratio of the mass of the sizing agent to the mass of the carbon fiber bundle in the center part and in both end parts, is 1.05-1.5.