PHA Multifilament Spinning with Staged Gas Cooling
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Solution Overview
Problem
The production of multifilaments with small average fineness of single filaments is hindered by filament breakage and fusion issues.
Innovation Solution
A method involving melt spinning with a spinning nozzle and controlled gas blowing to cool and crystallize poly(3-hydroxyalkanoate) resin filaments, using specific temperature ranges for gases to prevent breakage and fusion, with an average fineness of 15 dtex or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the average fineness of single filaments is reduced to achieve finer multifilament, then the manufacturing precision is improved, but the reliability deteriorates due to filament breakage and fusion
Solution Approach 1:
The patent applies parameter changes by precisely controlling the temperature of cooling air (from 0°C to 50°C) and heated air (from 50°C to 150°C) to manage the crystallization process of poly(3-hydroxyalkanoate) filaments. This temperature parameter optimization prevents both breakage and fusion, enabling production of ultra-fine filaments with average fineness of 15 dtex or less while maintaining high reliability
Solution Approach 2:
The patent implements preliminary action by performing a two-stage air blowing process: first blowing cooling air to initiate crystallization and prevent fusion, then blowing heated air to complete crystallization and prevent breakage. This preliminary controlled cooling prevents defects before they occur, enabling successful production of ultra-fine multifilaments
2Productivity
If conventional melt spinning is used to produce ultra-fine filaments, then the productivity is improved, but the manufacturing precision deteriorates due to inability to control fineness below 15 dtex
Solution Approach 1:
The patent changes the temperature parameters of the cooling and heating air to optimize crystallization control during melt spinning. By setting cooling air temperature between 0°C-50°C and heated air temperature between 50°C-150°C, the process achieves both high productivity and manufacturing precision, producing filaments with average fineness of 15 dtex or less
3Reliability
If the cooling rate is increased to prevent fusion, then the reliability is improved, but the manufacturing precision deteriorates due to filament breakage
Solution Approach 1:
The patent applies preliminary action by first blowing cooling air to initiate crystallization and prevent fusion, then subsequently blowing heated air to complete crystallization and prevent breakage. This two-stage approach ensures both fusion prevention and filament integrity are achieved
Solution Approach 2:
The patent implements periodic action through sequential air blowing: first cooling air is blown to prevent fusion, then heated air is blown to prevent breakage. This periodic switching of air temperature regimes enables simultaneous achievement of fusion prevention and filament integrity
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 effectively suppresses filament breakage and fusion, enabling the production of multifilaments with desirable fineness and processability.
Implementation Method 1
blowing a first gas onto the plurality of raw filaments in the molten state to cool the plurality of raw filaments
Implementation Method 2
Tc is a crystallization temperature of the poly(3-hydroxyalkanoate) resin
Data Source
AI summary
A method for producing a multifilament, comprising (A) heat-melting a raw material composition to obtain a molten product and discharging the molten product through the discharge holes to obtain a plurality of raw filaments in a molten state; and (B) blowing gases onto the plurality of raw filaments, comprising (B1) blowing a first gas onto the plurality of raw filaments in the molten state to cool raw filaments and (B2) blowing a second gas onto the plurality of raw filaments cooled in (B1). In (B1), a temperature of the first gas is (Tc−45° C.) to (Tc−30° C.), Tc is a crystallization temperature of the poly(3-hydroxyalkanoate) resin, and in (B2), a temperature of the second gas is higher than the temperature of the first gas, and is (Tc−30° C.) to (Tc−10° C.). The raw material composition contains a poly(3-hydroxyalkanoate) resin. An average value of fineness of the single filaments is 15 dtex or less.