Method for producing carbon fiber bundle
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Solution Overview
Problem
Existing methods for producing carbon fiber bundles face challenges such as coalescence and abrasion between monofilaments during stabilization and carbonization steps, leading to decreased strength and productivity due to contamination and process failures.
Innovation Solution
Applying a silicone oil agent with increased molecular weight, achieved by heating it to a skin over time of less than 40 minutes at 250°C, to a precursor fiber bundle before oxidization treatment, which prevents thermal decomposition and penetration into monofilaments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicone oil agent is applied to the precursor fiber bundle to prevent coalescence and abrasion, then the protection against thermal damage and friction is improved, but the silicone decomposes to generate fine dust that contaminates the stabilization furnace and decreases productivity
Solution Approach 1:
The patent changes the molecular weight parameter of the silicone oil agent by selecting specific viscosity ranges (10-1000 mm²/s at 25°C) and molecular weight characteristics. This parameter change modifies the thermal decomposition behavior, reducing fine dust generation while maintaining protective functions during stabilization and carbonization processes.
Solution Approach 2:
The patent uses composite oil agents comprising silicone oil combined with other materials such as metal soaps (calcium stearate, zinc stearate, etc.) or polyethylene glycol. This composite approach enhances the protective effect while controlling thermal decomposition and reducing contamination of the stabilization furnace.
2Reliability
If a silicone oil agent is applied to the precursor fiber bundle to prevent coalescence and abrasion, then the protection against thermal damage and friction is improved, but the fine dust contaminates the fiber bundle and decreases its strength
Solution Approach 1:
The patent optimizes the molecular weight and viscosity parameters of the silicone oil agent to control penetration depth. By selecting appropriate viscosity ranges (10-1000 mm²/s) and molecular weights, the oil agent forms a protective layer on the fiber surface without excessive penetration into monofilaments, thereby preventing strength degradation while maintaining protective effects.
Solution Approach 2:
The patent employs composite oil agents combining silicone oil with metal soaps or polyethylene glycol. These composite materials provide enhanced protection against coalescence and abrasion while controlling the decomposition behavior to minimize contamination and strength loss of the carbon fiber bundle.
3Reliability
If a silicone oil agent is applied to the precursor fiber bundle, then the protection against coalescence and abrasion is improved, but the gelled silicone oil agent attaches to process rollers or guides and causes process failure
Solution Approach 1:
The patent controls the gelation temperature and gelation time parameters of the silicone oil agent by selecting specific viscosity ranges and molecular weights. This ensures the oil agent remains in a liquid or semi-liquid state during the stabilization and carbonization processes, preventing attachment to process rollers or guides while maintaining protective functions.
Solution Approach 2:
The patent uses composite oil agents that incorporate gelation control mechanisms through combinations with metal soaps or polyethylene glycol. These composites regulate the gelation behavior to occur at appropriate stages, preventing premature gelation that would cause attachment to equipment while ensuring protective coverage of the fibers.
4Reliability
If a silicone oil agent is applied to the precursor fiber bundle, then the protection against coalescence and abrasion is improved, but the oil agent penetrates into monofilaments and forms voids that decrease strength
Solution Approach 1:
The patent optimizes the molecular weight and viscosity parameters of the silicone oil agent to control penetration depth. By selecting appropriate viscosity ranges (10-1000 mm²/s) and molecular weights, the oil agent forms a protective layer on the fiber surface with limited penetration into monofilaments, preventing void formation while maintaining protective effects against coalescence and abrasion.
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 method effectively prevents damage from coalescence and abrasion, reduces contamination of the stabilization furnace, and results in carbon fiber bundles with excellent physical properties and high strength.
Implementation Method 1
heating the oil-agent-attached precursor fiber bundle for carbon fiber to increase the molecular weight of the silicone
Implementation Method 2
the silicone in the silicone oil agent is rapidly increased in molecular weight to come into a gelled state
Implementation Method 3
the oxidized fiber bundle is carbonized in an inert atmosphere
Implementation Method 4
a method is generally employed in which a precursor fiber bundle is heated in an oxidizing atmosphere at 200 to 300° C. to be converted into an oxidized fiber bundle
Data Source
AI summary
The present invention provides a method for producing a carbon fiber bundle, the method including steps (b) to (e) described below:(b) an oil agent application step of applying a silicone oil agent to a precursor fiber bundle to produce an oil-agent-attached precursor fiber bundle;(d) a stabilization step of subjecting the oil-agent-attached precursor fiber bundle to an oxidization treatment to produce an oxidized fiber bundle; and(e) a carbonization step of carbonizing the oxidized fiber bundle, whereinthe silicone oil agent has a skin over time at 250° C. of less than 40 minutes.