Method for manufacturing oxidized fiber bundle, method for manufacturing carbon fiber bundle, and joining apparatus
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Solution Overview
Problem
The existing methods for manufacturing carbon fiber bundles face challenges such as fiber breakage at or near the joint during the oxidization and carbonization processes, leading to reduced productivity and increased trouble in the joining process.
Innovation Solution
A method involving the application of an oiling agent with a concentration of 0.15 to 0.85 wt% to the joint area of precursor fiber bundles before joining, followed by a heat-treatment and fluid-jetting process to enhance entanglement strength and stability, utilizing a joining apparatus with an oiling agent application unit, heat-treatment unit, and joining unit to facilitate the joining of upstream and downstream precursor fiber bundles with a joining fiber bundle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rate of production, linear density, and number of fiber bundles are increased, then productivity is improved, but fiber breakage at or near the joint occurs during oxidization and carbonization processes
Solution Approach 1:
The patent applies an oiling agent to the joint area of the precursor fiber bundle before joining with the joining fiber bundle. This preliminary treatment strengthens the joint area in advance, preventing fiber breakage during subsequent oxidization and carbonization processes, thereby enabling higher productivity without compromising reliability.
Solution Approach 2:
The patent specifies a precise quantity range for the oiling agent (0.15 to 0.85 wt%) to optimize joint strength. By controlling this parameter within the specified range, the joint area achieves sufficient strength to withstand the stresses of high-rate production processes without fiber breakage.
2Productivity
If a joining fiber bundle is used to join upstream and downstream precursor fiber bundles, then continuous production is enabled, but the joining process becomes complex and prone to troubles
Solution Approach 1:
The oiling agent application is performed as a preliminary step before joining, simplifying the overall joining process. This pre-treatment ensures that the joint area is properly prepared, reducing the complexity of the joining operation itself and minimizing potential troubles during the process.
Solution Approach 2:
By specifying a precise quantity range for the oiling agent (0.15 to 0.85 wt%), the patent simplifies process control and reduces variability in the joining process, thereby reducing complexity and potential troubles while maintaining continuous production capability.
3Strength
If the quantity of oiling agent is increased to strengthen the joint, then entanglement strength is improved, but excess oiling agent may cause problems during heat treatment
Solution Approach 1:
The patent specifies a precise quantity range for the oiling agent (0.15 to 0.85 wt%) to optimize the balance between joint strength and heat treatment compatibility. This controlled parameter ensures sufficient entanglement strength while preventing harmful effects from excess oiling agent during subsequent heat treatment processes.
Solution Approach 2:
The patent references conventional oiling agent types and applies them in a controlled manner, using established materials with known properties. This approach ensures that the oiling agent provides sufficient strength while maintaining compatibility with standard heat treatment processes, avoiding the need for specialized materials.
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
This approach results in high productivity and stability of the carbon fiber bundle production with reduced fiber breakage at the joint, achieving an entanglement strength of 25 mN/tex or more and maintaining high throughput yields in both the oxidization and carbonization processes.
Implementation Method 1
applying an oiling agent to a joint area of a joining target precursor fiber bundle before joining the joining target precursor fiber bundle and the joining fiber bundle together
Implementation Method 2
a heat-treatment unit that heat-treats the joining target fiber bundle having the oiling agent applied
Implementation Method 3
oxidizing the joined precursor fiber bundles by feeding the joined precursor fiber bundles through an oxidization furnace
Implementation Method 4
heating bundled carbon-fiber precursor fibers such as acrylic fibers to 200 to 300 °C in an oxidizing atmosphere
Implementation Method 5
jets a fluid to the overlap to join the heat-treated joining target fiber bundles and the joining fiber bundle together
Data Source
Figure 1
AI summary
A manufacturing method and an apparatus enable high productivity. A method for manufacturing an oxidized fiber bundle includes joining an upstream precursor fiber bundle and a downstream precursor fiber bundle together with a joining fiber bundle, and oxidizing the joined precursor fiber bundles by feeding the joined precursor fiber bundles through an oxidization furnace. The joining includes applying an oiling agent to a joint area of a joining target precursor fiber bundle before joining the joining target precursor fiber bundle and the joining fiber bundle together. A quantity of the oiling agent adhering to the joint area is 0.15 to 0.85 wt%.