Acrylic Fiber Finish Composition for Stable Carbon Fiber Processing
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Solution Overview
Problem
Existing finishes for carbon fiber production, particularly those containing antioxidants, fail to prevent fusing of carbon fibers during the baking process, leading to insufficient tenacity and instability in aqueous emulsions, resulting in nonuniform application and reduced production efficiency.
Innovation Solution
A finish comprising a modified silicone with a nitrogen-containing modifying group and a specific acidic phosphate ester, formulated to inhibit gumming up and fusing, while maintaining stability and heat resistance, is applied to the acrylic fibers before the drawing step, forming a stable emulsion for uniform application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amino-modified silicone finishes are used to prevent fiber adhesion and improve heat resistance, then fiber detaching property and heat resistance are improved, but gumming up on heater rollers occurs and precursor production efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the problematic thermal cross-linking behavior of amino-modified silicones by using alternative silicone compounds that do not cross-link at drying and drawing temperatures, thereby removing the gumming up issue while maintaining the desired heat resistance and fiber detaching properties
Solution Approach 2:
The patent changes the chemical parameters of the silicone finish by selecting specific silicone compounds with controlled reactivity, ensuring they remain stable at processing temperatures yet provide adequate heat resistance, thus preventing gumming up while maintaining productivity
2Productivity
If antioxidants are added to silicone finishes to inhibit gumming up, then gumming up is reduced, but silicone decomposition is accelerated and heat resistance deteriorates
Solution Approach 1:
The patent removes antioxidants from the finish formulation, recognizing that while they prevent gumming up, they cause silicone decomposition and loss of heat resistance. The solution extracts the harmful antioxidant component entirely
Solution Approach 2:
The patent develops a composite finish system using specific silicone compounds combined with acrylic resins and other additives that work synergistically to provide both gumming up prevention and heat resistance without requiring antioxidants
3Ease of operation
If aqueous emulsion finishes are used for application, then ease of application is improved, but emulsion stability deteriorates over time resulting in nonuniform application
Solution Approach 1:
The patent performs preliminary stabilization of the aqueous emulsion through careful formulation and pre-mixing procedures, ensuring the emulsion remains stable during storage and transport before application, thus preventing nonuniform application while maintaining ease of use
Solution Approach 2:
The patent introduces emulsifiers and stabilizing agents as intermediaries that maintain the integrity of the aqueous emulsion, preventing phase separation and ensuring uniform application properties over time
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 proposed finish effectively prevents fusing and gumming, enhancing the tenacity of the resultant carbon fibers and ensuring high production efficiency by maintaining a stable emulsion and heat resistance throughout the oxidative stabilization and carbonization processes.
Implementation Method 1
an aqueous finish which is made into a stable aqueous finish emulsion
Implementation Method 2
Amino-modified silicones have excellent thermal cross-linking performance, and their cross-linking behavior is accelerated on heater rollers in drying and drawing processes
Implementation Method 3
silicone finishes attaining low fiber-to-fiber wet friction in wet condition or at high temperature and excellent fiber detaching property
Implementation Method 4
a process of converting the precursor into an oxidized fiber in an oxidative atmosphere at 200 to 300 deg.C
Implementation Method 5
a process of carbonizing the oxidized fiber in an inert atmosphere at 300 to 2,000 deg.C
Data Source
AI summary
The present invention aims to provide an acrylic-fiber finish for carbon fiber production, which is prepared into a stable emulsion and applied to a carbon-fiber precursor to prevent gumming up of finish components in precursor production and carbon fiber fusing in baking process. The present invention provides an acrylic-fiber finish for carbon-fiber production comprising a modified silicone having a modifying group containing a nitrogen atom and an acidic phosphate ester represented by the following chemical formula (1). where R1 represents a C6-22 alkyl or alkenyl group, A represents a C2-4 alkylene group, and AO represents an oxyalkylene group, n represents a mole number of oxyalkylene group and is an integer ranging from 0 to 20, and each of a and b is an integer of 1 or 2 and meets the equation a + b = 3.