Flame-Retardant Carbon Fiber Bundle Manufacturing via Roller Spreading
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Solution Overview
Problem
Existing methods for manufacturing carbon fiber bundles face challenges such as adhesion between single fibers during stabilization, leading to reduced tensile strength, and high equipment costs or process inefficiencies.
Innovation Solution
A method involving the use of a roller group with continuously arranged small-diameter rollers to spread and bend the fiber bundle, applying external force to peel adhesion between single fibers during stabilization, and subsequent carbonization to produce high-strength carbon fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fiber bundle is stabilized in an oxidizing atmosphere at 200 to 300°C, then the carbon fiber bundle can be manufactured, but adhesion between single fibers occurs leading to reduced tensile strength
Solution Approach 1:
The fiber bundle is subjected to preliminary spreading and bending actions before the stabilization heat treatment. The fiber bundle is passed between rollers to spread it and apply bending, which prevents adhesion during the subsequent stabilization process in the oxidizing atmosphere at 200-300°C.
Solution Approach 2:
The fiber bundle is bent into a curved shape by passing it between rollers during the stabilization process. This curvature prevents the single fibers from adhering to each other by maintaining spatial separation, while still allowing the stabilization treatment to occur effectively.
2Productivity
If conventional stabilization equipment is used, then the process can be implemented, but equipment costs are high and process efficiency is low
Solution Approach 1:
The stabilization equipment is designed to perform multiple functions: spreading the fiber bundle, bending it, and conducting the stabilization heat treatment all in one integrated system. This eliminates the need for separate equipment for each operation, reducing overall equipment cost and improving process efficiency.
Solution Approach 2:
The spreading rollers and stabilization furnace are merged into a single integrated unit. The fiber bundle is spread and bent by rollers that are positioned within or directly connected to the stabilization chamber, combining what were previously separate operations into one continuous process.
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 suppresses adhesion between single fibers, resulting in carbon fiber bundles with enhanced tensile strength and improved process efficiency, while also reducing equipment costs.
Implementation Method 1
a fiber bundle is made to run, with respect to a roller group including m pieces (where m is an integer of 3 or more) of rollers arranged continuously, to sequentially pass between an n-th roller and an (n + 1)-th roller
Implementation Method 2
stabilizing a polyacrylonitrile precursor fiber bundle in an oxidizing atmosphere at 200 to 300°C to manufacture a stabilized fiber bundle
Implementation Method 3
carbonizing the stabilized fiber bundle in an inert atmosphere at 1000 to 2500°C
Data Source
Figure 1
Figure 2
Figure 3(1)~3(2)
AI summary
The purpose of the present invention is to provide: a method for manufacturing a flame-retardant fiber bundle, which is for obtaining a high strength carbon fiber, by loosening the adhesion among monofilaments caused during flame-retarding treatment; and a method for manufacturing a carbon fiber bundle. To achieve the above, this method for manufacturing a flame-retardant fiber bundle satisfies prescribed conditions and includes a step for manufacturing the flame-retardant fiber bundle by means of flame retarding treatment of a polyacrylonitrile-based precursor fiber at 200 - 300°C in an oxidizing atmosphere, wherein a fiber bundle is caused to travel so as to sequentially pass between an nth roller and an (n + 1)th roller (n being an integer of at least 1 and no more than [m - 1]) in a roller group formed from m (m being an integer of 3 or greater) contiguously set rollers, the roller axes of the m continuously set rollers being parallel to each other and perpendicular to the direction of travel of the fiber bundle, the roller diameter being 5 -30 mm, and the specific gravity of the fiber bundle being 1.20 - 1.50.