Carbon Fiber Bundle Sizing for Adhesion and Fiber Opening
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Solution Overview
Problem
Carbon-fiber bundles used in thermoplastic resin compositions face challenges with adhesiveness and processability, as existing sizing agents either fail to provide sufficient fiber opening or reduce mechanical characteristics when used in high concentrations.
Innovation Solution
A carbon-fiber bundle with a mixture of an organic polymer substance and an organic compound adhered at specific mass percentages, where the organic polymer has a weight-average molecular weight of 10000 or greater and the organic compound has a thermal loss rate of 5% or greater, enhancing interfacial adhesion and processability without compromising mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a polymer material sizing agent is used on carbon-fiber bundles, then convergence of carbon-fiber bundles is improved, but processability such as ease of winding or opening fibers remains low because the polymer material is solid at room temperature
Solution Approach 1:
The patent changes the physical state parameter of the sizing agent from solid to liquid at room temperature by using a specific ester compound. This allows the sizing agent to provide convergence while maintaining excellent processability during handling and manufacturing operations.
Solution Approach 2:
The patent utilizes the phase transition property of esters with melting points below room temperature, allowing the sizing agent to remain liquid during application and handling, then solidify only when needed for convergence, optimizing both processability and structural stability.
2Ease of operation
If nonionic surfactant is added to sizing agent to improve fiber opening properties, then processability is enhanced, but mechanical characteristics of the formed materials are reduced when surfactant content exceeds certain level
Solution Approach 1:
The patent uses a specific ester compound as an intermediary sizing agent that provides fiber opening properties without the harmful effects of excessive surfactant. The ester acts as a mediator between the carbon fiber and the subsequent thermoplastic resin, enabling good processability while preserving mechanical strength.
Solution Approach 2:
The patent employs a volatile ester compound that serves its purpose during manufacturing and then decomposes or evaporates, leaving no harmful residue that would compromise mechanical properties. This temporary agent provides necessary processability without long-term negative effects.
3Ease of operation
If glycol ether-based compound content in sizing agent is increased to improve fiber opening, then processability is enhanced, but adhesiveness between carbon fibers and matrix resin is reduced
Solution Approach 1:
The patent changes the chemical structure parameter by using a specific ester compound instead of glycol ether-based compounds. This structural change allows the sizing agent to provide fiber opening properties while maintaining compatibility and adhesiveness with the thermoplastic matrix resin.
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 achieves excellent interfacial adhesion and processability in carbon-fiber-reinforced thermoplastic resin compositions, maintaining mechanical characteristics and enabling the production of high-quality molded products.
Implementation Method 1
an organic compound (B) with a rate of thermal loss of 5 mass % or more when determined under the measurement condition below is adhered
Implementation Method 2
heated at 200° C. for 10 minutes in an air flow of 50 L (volume at 25° C. under 1 atmospheric pressure) per minute
Data Source
AI summary
A carbon fiber bundle for resin reinforcement, wherein there are adhered by 0.1-5.0 mass % to a carbon fiber bundle in which multiple lengths of filament are bundled, a mixture created by mixing an organic polymer (A) having a mass-average molecular weight of 10000 or more and an organic compound (B) the thermal reduction rate specified in claim 1 of which is 5 mass % or more or an organic compound (B) the thermal reduction rate specified in claim 2 of which is 0.8 mass % or more, the amount of the organic polymer (A) adhered being 0.1 mass % or more.