Polyamide Yarn Solid Phase Polycondensation Spinneret Deposit Control
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Solution Overview
Problem
The polyamide yarn manufacturing process is hindered by frequent interruptions due to filament bending caused by deposits on the spinneret plate, leading to reduced productivity and yarn quality, especially with higher TiO2 content, which is undesirable in apparel applications.
Innovation Solution
Increasing the flow rate of a purge gas, such as nitrogen and water vapor, and lowering the pressure in the solid phase polycondensation apparatus enhances the removal of thermal degradation products, thereby extending the spinneret wipe life and improving yarn quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TiO2 content is increased to provide dull luster filaments, then apparel application acceptability is improved, but filament bending and process interruptions increase
Solution Approach 1:
The patent applies preliminary action by treating the polyamide polymer flakes with a purge gas (nitrogen or other inert gas) before the spinning process to remove thermal degradation products that cause filament bending. This preventive treatment extends the spinneret wipe cycle life and reduces process interruptions, allowing the use of higher TiO2 content (1-3% by weight) for dull luster filaments without the associated reliability problems.
2Reliability
If spinneret wiping frequency is increased to remove deposits, then filament bending is reduced, but productivity decreases
Solution Approach 1:
The patent applies preliminary action by treating the polyamide polymer flakes with a purge gas (nitrogen or other inert gas) before the spinning process to remove thermal degradation products that cause filament bending. This preventive treatment extends the spinneret wipe cycle life and reduces process interruptions, allowing the use of higher TiO2 content (1-3% by weight) for dull luster filaments without the associated reliability problems.
Solution Approach 2:
The patent extracts the harmful thermal degradation products from the polymer flake using a purge gas flow through the solid phase polycondensation apparatus. This extraction of harmful substances prevents deposit formation on the spinneret plate, extending the time between wiping operations and improving overall productivity.
3Duration of action of stationary object
If purge gas flow rate is increased to remove thermal degradation products, then spinneret wipe life is extended, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by optimizing the purge gas flow rate and pressure conditions in the solid phase polycondensation apparatus. By carefully controlling these parameters, the system achieves effective removal of thermal degradation products to extend spinneret wipe life while minimizing excessive energy consumption associated with overly aggressive gas flow rates.
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 approach significantly extends the time between spinneret wiping events, increases productivity, and enhances yarn quality by reducing filament breaks and defects, resulting in a more efficient and higher-quality polyamide yarn production process.
Implementation Method 1
supplying a purge gas, comprised of nitrogen and water vapor, to the solid phase polycondensation apparatus at a rate in the range of about 2 to about 3 kg/hour per kg of polyamide polymer per hour; treating the polyamide polymer in the solid phase polycondensation apparatus with the purge gas
Data Source
AI summary
A process for making a synthetic melt spun polyamide filament in a solid phase polycondensation apparatus is disclosed. The flow rate of the purge (make-up) gas to the apparatus is increased, and the overall pressure in the apparatus is decreased, as compared to solid phase polycondensation apparatus of the prior art. As a result, the removal of the thermal degradation impurity from the polymer flake contributes to improving the yarn quality and at the same time, extends the spinneret wipe life.