Carbon Fiber Bundle Sizing for Convergence and Aqueous Dispersibility
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Solution Overview
Problem
Existing carbon fiber bundles face challenges in achieving a balance between convergence property and dispersibility in aqueous dispersion media, particularly at high carbon fiber concentrations, leading to degraded substrate quality and reduced mechanical and conductive properties.
Innovation Solution
A carbon fiber bundle with a sizing agent comprising a water-soluble polyurethane resin, specifically formulated with a polyoxyalkylene unit, aromatic ester unit, and aromatic or aliphatic urethane unit, deposited at an optimal ratio to enhance handleability, convergence, and dispersibility, ensuring uniform dispersion and improved paper quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sizing agent is deposited on carbon fibers to improve convergence property, then handleability and convergence are improved, but dispersibility in aqueous medium deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the deposition amount of the sizing agent within a specific range (0.1-5 mass%, preferably 0.3-3 mass%). This quantitative parameter control allows the fiber bundle to achieve both good convergence property for handling and sufficient dispersibility in aqueous medium, resolving the contradiction between ease of operation and manufacturing precision
Solution Approach 2:
The patent uses a composite sizing agent system combining water-soluble polyvinyl alcohol (PVA) with specific additives. This composite material approach creates a sizing agent that provides both convergence enhancement and maintains dispersibility, as the PVA base combined with controlled additives achieves balanced performance for both handling and dispersion requirements
2Productivity
If carbon fiber concentration in aqueous dispersion medium is increased to obtain high fabric weight paper, then productivity is improved, but mechanical property deteriorates due to insufficient dispersibility
Solution Approach 1:
The patent controls the sizing agent deposition amount within an optimized range (0.1-5 mass%, preferably 0.3-3 mass%) to maintain effective dispersibility even at high carbon fiber concentrations. This parameter control ensures that increased fabric weight does not lead to fiber reaggregation, thereby maintaining mechanical properties while improving productivity
Solution Approach 2:
The patent applies partial action by using a minimal effective amount of sizing agent (0.1-5 mass%) rather than excessive deposition. This sufficient but not excessive sizing achieves the needed convergence property while leaving enough fiber surface available for water-mediated dispersion, enabling high concentration processing without mechanical property degradation
3Stability of the object's composition
If sizing agent deposition amount is increased to improve convergence property, then convergence is improved, but dispersibility and substrate quality deteriorate
Solution Approach 1:
The patent establishes an optimized deposition amount range (0.1-5 mass%, preferably 0.3-3 mass%) that balances convergence property and substrate quality. Within this parameter range, the fiber bundle maintains stable convergence for handling while ensuring sufficient dispersibility for high-quality substrate formation, resolving the contradiction between composition stability and manufacturing precision
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 carbon fiber bundle achieves excellent handleability and balanced convergence and dispersibility, even at high concentrations, resulting in enhanced mechanical and conductive properties of the composite material, with improved substrate quality and processability.
Implementation Method 1
a sizing agent is deposited on the carbon fibers
Implementation Method 2
convergence property and dispersibility in an aqueous dispersion medium
Implementation Method 3
a water soluble polyurethane resin having an SP value of 11.2 to 13.3
Data Source
AI summary
A carbon fiber bundle has carbon fibers and a sizing agent, wherein the sizing agent comprises a water soluble polyurethane resin having an SP value of 11.2 to 13.3, and the sizing agent is deposited on the carbon fibers at a rate of 0.5 to 7% by mass. In another carbon fiber bundle, the sizing agent is composed of the component shown in (A) and the component shown in (B1) or (B2) below, and the sizing agent is deposited on the carbon fibers at a rate of 0.5 to 7% by mass: (A) 73 to 98% by mass of a polyoxyalkylene unit; (B1) 0.5 to 15% by mass of an aromatic ester unit, 1.5 to 10% by mass of an aromatic urethane unit; and (B2) 0.5 to 10% by mass of an aromatic ester unit, 1.5 to 11% by mass of an aliphatic urethane unit.