Spun Yarn from CFRP Scrap via Controlled Carbonization
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Solution Overview
Problem
Current methods for recycling carbon fiber-reinforced plastic (CFRP) scrap are inefficient and result in deterioration of mechanical properties and conductivity due to the high tensile modulus and carbon content of carbon fibers, making it difficult to manufacture high-quality spun yarn from recycled materials.
Innovation Solution
The development of spun yarn comprising carbon fiber staples with 97% or more carbon content, obtained by carbonizing CFRP scrap at 900°C to 1,400°C, blended with thermoplastic resin fibers and processed through carding, combing, and spinning with a twist of 100 to 200 TPM, to achieve a tensile modulus of 30 GPa to 120 GPa and surface resistance of 1×10^-5 to 1×10^-3 Ω·cm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon fibers with high carbon content and high tensile modulus are used in recycled CFRP scrap, then mechanical properties are improved, but the fibers break during processing making it difficult to manufacture molded articles
Solution Approach 1:
The patent changes the physical-chemical parameters of carbon fibers by controlling carbonization temperature (900-1400°C) and duration to achieve optimal carbon content (97-99.5%) and tensile modulus (100-1000 GPa). This parameter optimization prevents fiber breakage during processing while maintaining high mechanical properties in the final product.
Solution Approach 2:
The patent creates a composite structure by combining optimized carbon fiber staples with thermoplastic resin fibers. The carbon fibers provide high strength and stiffness, while the thermoplastic matrix provides ductility and processability, resolving the contradiction between mechanical properties and ease of manufacture.
2Reliability
If carbon fibers are carbonized at high temperature to increase carbon content, then conductivity is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent optimizes carbonization parameters (temperature range of 900-1400°C, duration of 1-24 hours) to achieve the desired balance between conductivity and process simplicity. By establishing clear parameter ranges, the complex carbonization process becomes controllable and repeatable, reducing manufacturing complexity while maintaining high conductivity (surface resistance of 1×10^-5 to 1×10^-3 Ω·cm).
3Productivity
If conventional recycling methods are used for CFRP scrap, then recycling is achieved, but mechanical properties and conductivity deteriorate
Solution Approach 1:
The patent fundamentally changes the recycling approach by implementing controlled carbonization with specific temperature (900-1400°C) and time parameters, rather than conventional low-temperature processing. This parameter change preserves the high carbon content (97-99.5%) and tensile modulus of the fibers, preventing deterioration of mechanical properties and conductivity during recycling.
Solution Approach 2:
The patent replaces mechanical recycling methods (cutting, grinding) with thermal-chemical carbonization processes. This substitution allows for controlled transformation of CFRP scrap into high-quality carbon fiber staples that maintain their mechanical properties and conductivity, overcoming the limitations of conventional mechanical recycling.
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 allows for the economic recycling of CFRP scrap without compromising mechanical properties and conductivity, producing spun yarn with improved tensile modulus and surface resistance, suitable for use in composite manufacturing operations.
Implementation Method 1
carbonizing carbon fiber-reinforced plastic scrap at 900°C to 1,400°C
Data Source
AI summary
Disclosed herein is spun yarn and a method of preparing the same. The spun yarn includes carbon staple fibers including 97 wt% or more of carbon, and thermoplastic resin fibers. The spun yarn includes carbon staple fibers prepared from scrap generated during manufacture of carbon fiber-reinforced plastic products, and has good mechanical properties and conductivity.