Melt-Anisotropic Aromatic Polyester Fiber for Creep Resistance
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Solution Overview
Problem
Existing melt-anisotropic aromatic polyester fibers lack sufficient creep properties and dimensional stability, which are crucial for applications requiring long lifetimes and resistance to deformation.
Innovation Solution
The production method involves melt-kneading aromatic polyester using a twin-screw extruder at a temperature below its melting point, applying shear force to achieve a uniform microcrystal structure, followed by heat-treating the as-spun fiber to enhance orthorhombic crystallinity and density, resulting in a fiber with improved creep properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional melt-spinning methods are used, then production efficiency is maintained, but the creep property and dimensional stability of the fiber are insufficient
Solution Approach 1:
The patent applies parameter changes by controlling the barrel temperature to be lower than the melting point of the aromatic polyester during melt-kneading, and by controlling residence time to be 10 seconds or longer. These parameter changes enable the formation of a uniform microcrystal structure that increases orthorhombic crystallinity, thereby improving creep property while maintaining production efficiency through optimized processing conditions.
Solution Approach 2:
The patent applies preliminary action by performing melt-kneading at controlled temperature and residence time before spinning to pre-form a uniform microcrystal structure in the polymer melt. This preliminary structuring during kneading ensures that the subsequent spinning and heat-treating processes produce fibers with high orthorhombic crystallinity and excellent creep resistance without requiring additional processing steps.
2Stability of the object's composition
If heat-treating is performed to increase crystallinity, then dimensional stability improves, but production time increases
Solution Approach 1:
The patent applies preliminary action by forming a uniform microcrystal structure during the melt-kneading process before spinning. This pre-structured melt requires less time for heat-treating to achieve the desired orthorhombic crystallinity, thereby reducing production time while maintaining excellent dimensional stability in the final fiber product.
Solution Approach 2:
The patent applies parameter changes by controlling the heat-treating temperature and time to optimize the conversion to orthorhombic crystals. By adjusting these parameters based on the pre-formed microcrystal structure from melt-kneading, the patent achieves high dimensional stability with minimized production time.
3Manufacturing precision
If shear force is applied during kneading, then microcrystal uniformity improves, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by controlling the barrel temperature to be lower than the melting point during melt-kneading. This temperature control increases the viscosity of the polymer melt, making it more responsive to shear force application. As a result, uniform microcrystals form more efficiently with less energy input, improving manufacturing precision while controlling energy consumption.
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 resulting fiber exhibits enhanced creep resistance and stability due to a higher degree of orthorhombic crystallinity and density, with improved mechanical properties and reduced fiber breakages during spinning.
Implementation Method 1
kneading a melt-anisotropic aromatic polyester at a low temperature in a twin-screw extruder enables to apply a shear force to the melt-anisotropic aromatic polyester in a state where the viscosity thereof is high
Implementation Method 2
heat-treating the as-spun fiber to cause solid-phase polymerization
Implementation Method 3
a melt-anisotropic aromatic polyester fiber having a high degree of orthorhombic crystallinity
Implementation Method 4
melt-kneading a melt-anisotropic aromatic polyester using a twin-screw extruder at a barrel temperature, from a resin feed portion to a kneading portion outlet, of lower than a melting point Mp0
Data Source
Figure 1
AI summary
Provided is a melt-anisotropic aromatic polyester fiber having excellent creep properties. The melt-anisotropic aromatic polyester fiber has a degree of orthorhombic crystallinity of 15.0% or more in a crystal component. For example, the melt-anisotropic aromatic polyester fiber may have a density of 1.4080 g/cm3 or more as determined using a density gradient tube. The melt-anisotropic aromatic polyester fiber may include a melt-anisotropic aromatic polyester having a structural unit derived from 4-hydroxybenzoic acid at a proportion of 50 mol% or more.