Extrusion Gas Flow Segmentation for Polymer Filament Quality
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Solution Overview
Problem
Existing extrusion processes for forming polymer solutions or fluids, such as cellulose in N-methylmorpholine-N-oxide (NMMO), often result in undesirable particle formation and contamination due to rapid cooling and solidification, leading to deposits on equipment and quality issues in the final product.
Innovation Solution
A method involving a controlled gas stream with a heating sub-stream and a cooling sub-stream is applied between the extrusion openings and the collecting bath, where the material is first exposed to the heating sub-stream and then the cooling sub-stream, preventing solidification and particle formation on the extruder or spinning threads, and reducing stickiness by maintaining a laminar gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid cooling and solidification is applied after extrusion, then productivity is improved by faster processing, but particle formation and contamination increase, worsening product quality
Solution Approach 1:
The gas stream is divided into two separate sub-streams: a heating sub-stream and a cooling sub-stream. This segmentation allows independent control of temperature zones, enabling the material to be heated to prevent particle formation while simultaneously cooling to maintain productivity, thus resolving the contradiction between processing speed and product quality
Solution Approach 2:
Different thermal conditions are applied to different regions of the extruded material. The heating sub-stream acts on the material surface or specific zones prone to particle formation, while the cooling sub-stream acts on other regions. This local differentiation allows simultaneous prevention of contamination and maintenance of high processing speed
2Productivity
If cooling is applied immediately after extrusion, then solidification is accelerated improving productivity, but stickiness increases causing deposits on equipment
Solution Approach 1:
The heating sub-stream is applied before the cooling sub-stream to preliminarily modify the material state. By heating the material first, particle formation is prevented and stickiness is reduced, creating favorable conditions for subsequent cooling without causing deposits on equipment
Solution Approach 2:
The heating sub-stream acts as an intermediary between extrusion and cooling. It temporarily increases material temperature to reduce viscosity and stickiness, preventing deposits during the transition phase, before the cooling sub-stream completes the solidification process
3Manufacturing precision
If the material is kept in fluid state longer to prevent particle formation, then product quality is improved, but residence time increases reducing productivity
Solution Approach 1:
The material undergoes periodic thermal treatment with alternating heating and cooling phases. The heating phase maintains fluid state to prevent particle formation, while the cooling phase rapidly solidifies to minimize total residence time, thus resolving the contradiction between quality improvement and productivity maintenance
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 effectively prevents particle formation and contamination, ensuring the quality of the extruded filaments or films by maintaining the material in a fluid state longer, reducing turbulence, and optimizing residence times within the gas flow zones.
Implementation Method 1
the material is first brought into contact with the heating sub-stream
Implementation Method 2
and then the cooling sub-stream before it is brought into the collecting bath
Implementation Method 3
maintaining a laminar gas flow
Data Source
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AI summary
The invention relates to a method for producing solid material filaments or films from a fluid of the material, by extruding the fluid by means of one or more extrusion openings and by solidifying the material in a precipitation bath. The formed material is guided between the extrusion openings and the precipitation bath by a lateral gas flow. The invention is characterized in that the gas flow is subdivided into a hot partial flow and a cold partial flow. The material is initially brought into contact with the hot partial flow and subsequently with the cold partial flow prior to it being introduced into the precipitation bath. The invention also relates to a device for extruding and forming materials.