Modular Disk Coextrusion Die for Multilayer Film Uniformity
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Solution Overview
Problem
Existing modular disk coextrusion dies are limited in producing multilayer blown films with high numbers of uniform and continuous nanolayers due to unbalanced melt pressures and limited entry points for polymer streams, leading to nonuniform layer thickness and potential breaks in thin layers.
Innovation Solution
A modular disk coextrusion die with a symmetrical arrangement of thin annular disks, including central routing disks and distribution disks oriented 180 degrees opposed to each other, allows for the production of blown films with up to several hundred layers using multiple polymer streams, ensuring equal melt pressures and uniform layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple polymer streams are used to increase the number of layers, then the layer count increases, but melt pressure becomes unbalanced and layer uniformity deteriorates
Solution Approach 1:
The patent applies asymmetry by positioning distribution inlet openings at specific angular orientations (e.g., 0°, 90°, 180°, 270°) around the central routing disk, creating a symmetrical pattern that balances melt pressure distribution. This symmetrical arrangement of inlet openings ensures that polymer streams from multiple extruders are distributed uniformly across the die, preventing pressure imbalances even when using many polymer streams to achieve high layer counts.
Solution Approach 2:
The patent achieves equipotentiality by designing the distribution disk with multiple inlet openings positioned symmetrically around the central routing disk, ensuring that all polymer streams experience similar flow path lengths and resistance. This creates equal pressure conditions for all layers, allowing uniform layer thickness and continuity even when producing films with hundreds of layers using numerous polymer streams.
2Quantity of substance
If more entry points are added to increase polymer streams, then the number of layers increases, but the structural complexity of the die increases
Solution Approach 1:
The central routing disk serves multiple functions: it distributes melt from multiple inlet openings (providing entry points for multiple polymer streams), it routes melt to various distribution disks, and it maintains pressure balance across all streams. This multi-functional design allows the die to accommodate many polymer streams without proportionally increasing structural complexity, as the central routing disk handles all distribution tasks centrally.
Solution Approach 2:
The die is segmented into modular components: a central routing disk with multiple inlet openings, multiple distribution disks with outlet openings, and multiple cells that can be stacked. This segmentation allows the system to scale to high layer counts by simply adding more distribution disks or stacking more cells, rather than redesigning the entire die structure, thus managing complexity through modularity.
3Quantity of substance
If thin annular disks are stacked to increase layer count, then the number of layers increases, but layer continuity and strength deteriorate
Solution Approach 1:
The patent changes the parameter of disk thickness optimization, using thin annular disks (e.g., 0.005 to 0.02 inches thick) that are thin enough to enable high layer counts when stacked, yet thick enough to maintain structural integrity and ensure continuous, unbroken layers. The thinness allows for better melt distribution and layer uniformity, while the controlled thickness prevents layer breaks and maintains strength.
Solution Approach 2:
The patent uses hydraulic principles by designing the distribution disks with inlet and outlet openings that create controlled pressure gradients for melt flow. The distribution inlet openings receive pressurized polymer melt, and the distribution outlets deliver it uniformly to the thin annular disks. This hydraulic control ensures that even very thin layers are formed continuously without breaks, as the pressure gradient maintains steady melt flow through the thin disk structures.
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 die enables the production of complex multilayer films with continuous, unbroken, and uniformly thick nanolayers, overcoming the limitations of previous technologies by achieving high numbers of layers with improved symmetry and stability, and allowing for a wide range of barrier properties through careful polymer selection.
Implementation Method 1
Each distribution disk includes a distribution inlet opening, a plurality of outlet openings, and a plurality of channels connecting the distribution inlet opening with the plurality of outlet openings
Implementation Method 2
Each spreader disk includes a plurality of flow ports, each connected and leading into a flat flow region
Implementation Method 3
modular disk coextrusion die with a symmetrical arrangement of thin annular disks
Data Source
Figure 1~1(b)
Figure 2
Figure 3
AI summary
A modular disk coextrusion die is formed of a plurality of cells stacked together. Each cell includes a symmetrical arrangement of thin annular disks, including a central routing disk and two distribution disks on both sides of the central routing disk. The distribution disks are oriented so that their respective distribution inlet openings oppose each other by about 180 degrees. The symmetrical arrangement permits each cell to process the melt streams in a manner that provides enhanced layer uniformity and bubble stability. By stacking several cells, blown films having up to several hundred layers can be made using twelve, twenty-four or more polymer melt streams. Complex films made from the modular disk coextrusion die are also provided.