Manufacturing method for carbon fiber

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Solution Overview

Problem

The manufacturing process of carbon fibers faces challenges such as protofilaments softening and sticking due to high temperatures, leading to defects like hairiness, and existing oiling agents have issues with poor film formation, heat resistance, stability, and hydrophilicity, complicating the process.

Innovation Solution

A manufacturing method involving the formation of an oiling agent through emulsification of γ-divinyltriamine propylmethyldimethoxyl silane and N-(β-aminoethyl)-γ-aminopropylmethylbimethoxy silane, which provides improved stability, hydrophilicity, and thermal resistance, allowing for effective protection of carbon raw filaments during calcination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a commonly used oiling agent is applied to prevent protofilament sticking, then film formation is achieved, but heat resistance is poor

Engineering Contradiction:
Improvefilm formationVSAvoidheat resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the oiling agent by incorporating silicon-containing compounds with specific functional groups (hydroxyl, carboxyl, amino groups) that can withstand high temperatures. This transforms the oiling agent from one that forms film but lacks heat resistance to one that maintains both film formation and heat resistance up to 400°C

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite oiling agent system combining silicon-containing compounds with specific functional groups, emulsifiers, and other additives. This composite formulation achieves synergistic effects where the silicon-containing compounds provide heat resistance while other components ensure proper film formation and stability

Inventive Principle:
Principle #40Composite materials

2Temperature

If modified oiling agents are developed to improve heat resistance, then thermal stability is enhanced, but film formation becomes poor

Engineering Contradiction:
Improveheat resistanceVSAvoidfilm formation
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent adjusts the molecular structure parameters of the oiling agent by selecting silicon-containing compounds with specific functional groups (hydroxyl, carboxyl, amino) that balance both thermal stability and film-forming capability. The functional groups enable proper adhesion and film formation while the silicon backbone provides heat resistance

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the oiling agent composition is simplified to improve manufacturing process, then process complexity is reduced, but stability and hydrophilicity deteriorate

Engineering Contradiction:
Improvemanufacturing process complexityVSAvoidoiling agent stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent makes the silicon-containing compound serve multiple functions simultaneously: it acts as the base oil providing heat resistance, contains functional groups that enable film formation and adhesion, and provides hydrophilicity through polar groups. This multi-functionality simplifies the overall formulation while maintaining stability

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Productivity

If high temperature calcination is performed to carbonize protofilaments, then carbon fiber is formed, but protofilaments soften and stick together

Engineering Contradiction:
Improvecarbon fiber productionVSAvoidfiber quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies the oiling agent containing silicon-containing compounds to the protofilament surface before calcination. This pre-applied coating acts as a protective cushion that prevents direct contact and sticking between protofilaments during high-temperature calcination, thereby preventing defects while allowing complete carbonization

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 method results in carbon fibers with enhanced mechanical strength and reduced defects, with the oiling agent maintaining greater than 90% weight at 273°C and 80% at 428°C, ensuring effective protection and efficient processing.

Implementation Method 1

soaking a carbon raw filament in the oiling agent, such that the oiling agent is adhered to a surface of the carbon raw filament to form a carbon fiber precursor

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

performing an emulsification step that includes uniformly mixing a silicone oil composition and an emulsifier to form an oiling agent

Methodology Applied
Scientific EffectEmulsification: Emulsion

Implementation Method 3

when carrying out a thermogravimetric analysis on the oiling agent in air, a weight of the oiling agent at a temperature of 273°C to 277°C is greater than 90% to 95% of an original weight of the oiling agent

Methodology Applied
Scientific EffectThermal stability: Thermal Insulation

Data Source

PatentEP4123066B1Manufacturing method for carbon fiber
Publication Date: 2024.04.10 TAIWAN SOKOU INDS KOFUN YUUGENKOUSHI
  • EP4123066B1 patent drawingFigure 1
  • EP4123066B1 patent drawingFigure 2

AI summary

A manufacturing method for a carbon fiber includes: performing an emulsification step that includes uniformly mixing a silicone oil composition and an emulsifier to form an oiling agent, in which the silicone oil composition includes γ-divinyltriamine propylmethyldimethoxyl silane and N-(β-aminoethyl)-γ-aminopropylmethylbimethoxy silane; performing an oiling step that includes soaking a carbon raw filament in the oiling agent, such that the oiling agent is adhered to a surface of the carbon raw filament to form a carbon fiber precursor; and performing a calcination step on the carbon fiber precursor, such that the carbon fiber is formed.