Multifilament Spinning Nozzle Layout for Breakage and Fusion Control
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Solution Overview
Problem
Existing methods for producing multifilaments with poly(3-hydroxybutyrate) resin face challenges in productivity due to filament breakage and fusion, particularly when increasing the haul-off roll speed.
Innovation Solution
A method involving a spinning nozzle with non-uniformly distributed discharge holes, where the peripheral region has a higher density of discharge holes, and gas cooling at specific temperatures and speeds to control crystallization and cooling, facilitating efficient production of multifilaments with 50 or more single filaments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the roll speed at the time of hauling off the filamentous resin composition is increased to increase productivity, then productivity is improved, but filament breakage or fusion of single filaments occurs
Solution Approach 1:
The patent applies parameter changes by precisely controlling the temperature of the gas flow within a specific range (Tc-45 to Tc-20°C) and adjusting the gas flow speed (0.01 to 0.10 m/s). These parameter adjustments optimize the cooling rate of the resin composition, enabling higher haul-off speeds without causing filament breakage or fusion, thus resolving the contradiction between productivity and filament integrity
Solution Approach 2:
The patent implements preliminary action by applying a controlled gas flow to cool the resin composition before it reaches the haul-off roll. This pre-cooling action reduces the temperature of the resin to an optimal range that prevents filament breakage and fusion during the subsequent high-speed hauling process, thereby enabling increased productivity without sacrificing reliability
2Temperature
If the gas flow speed is increased below 0.1 m/s to improve cooling effect, then cooling efficiency is improved, but the cooling effect becomes too small to prevent filament issues
Solution Approach 1:
The patent resolves this contradiction by changing the parameters of both temperature and speed simultaneously. By setting the gas flow speed within 0.01 to 0.10 m/s and the temperature within Tc-45 to Tc-20°C, the patent achieves an optimal balance where sufficient cooling effect is obtained without requiring excessively high gas flow speeds, enabling both effective cooling and maintained productivity
3Temperature
If the temperature of the gas is adjusted to control cooling, then cooling control is improved, but filament breakage or fusion still occurs at conventional conditions
Solution Approach 1:
The patent applies parameter changes by establishing a specific temperature range (Tc-45 to Tc-20°C) for the cooling gas. This controlled temperature range provides optimal cooling that prevents both excessive cooling (which causes brittleness and breakage) and insufficient cooling (which causes fusion), thereby resolving the contradiction between cooling control and filament integrity
Solution Approach 2:
The patent implements feedback by using the crystallization temperature (Tc) of the resin composition as a reference point to determine the optimal gas temperature range. This feedback mechanism ensures that the cooling gas temperature is always adjusted relative to the material's thermal properties, preventing filament breakage and fusion while maintaining reliable production
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 enhances productivity by reducing filament breakage and fusion, allowing for higher haul-off speeds and consistent fineness, resulting in improved multifilament production efficiency.
Implementation Method 1
cooling the raw filaments by blowing gas onto the raw filaments in the molten state
Implementation Method 2
Tc is a crystallization temperature of the composition including the poly(3-hydroxyalkanoate) resin
Data Source
AI summary
A method for producing a multifilament including 50 or more single filaments by melt spinning is provided. The method includes the steps of (A) obtaining 50 or more raw filaments in a molten state by discharging a composition including a poly(3-hydroxyalkanoate) resin from a spinning nozzle, and (B) cooling the raw filaments by blowing gas onto the raw filaments in the molten state. The spinning nozzle includes a nozzle surface including 50 or more discharge holes. The nozzle surface is segmented into a central region and a peripheral region surrounding the central region. An outer edge of the central region and an outer edge of the peripheral region are similar in shape to each other and share a same area centroid. A similarity ratio between the outer edge of the central region and the outer edge of the peripheral region is 1:2.