Layer Sequence Repeater Module for Multilayer Coextruded Films
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Solution Overview
Problem
Conventional annular co-extrusion dies face challenges in producing multi-layer products with a large number of thin layers due to increased bulkiness and limitations in layer thickness, which affects film properties and compatibility of materials.
Innovation Solution
A layer sequence repeater module comprising thin annular disks, including cap disks, distribution disks, repeater disks, and spreader disks, that distribute and form multiple layers with alternating flow directions, allowing for the production of nano-layers that are significantly thinner than micro-layers, enabling more layers to be produced within the same die thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of layers is increased in conventional modular annular dies, then more material combinations can be achieved, but the module becomes more bulky and the layer thickness control becomes limited
Solution Approach 1:
The patent implements nesting by placing multiple flow paths within the same die space using concentric annular regions. Different material layers are extruded through nested annular channels where inner channels produce thinner layers than outer channels, allowing multiple layers to occupy the same radial space without increasing die thickness proportionally
Solution Approach 2:
The patent transitions from conventional planar layer stacking to three-dimensional concentric annular layer formation. By utilizing radial and axial dimensions simultaneously through multiple extrusion ports at different radii and heights, the system produces multiple layers within the same overall die thickness envelope
2Manufacturing precision
If conventional annular dies are used to produce more thin layers, then film properties can be enhanced, but the residence time of melts increases causing degradation
Solution Approach 1:
The patent divides the extrusion process into multiple independent flow paths, each with its own extrusion port and flow channel. This segmentation allows each material stream to be extruded separately and simultaneously, reducing the residence time for each individual layer while maintaining precise thickness control through dedicated flow control for each segment
Solution Approach 2:
The patent pre-configures multiple extrusion ports and flow channels in advance, with each path optimized for specific layer requirements. This preliminary arrangement eliminates the need for sequential layer formation, allowing all layers to be extruded simultaneously through pre-established pathways, thereby minimizing residence time while maintaining precision
3Adaptability or versatility
If micro-layers are produced in conventional dies, then specialty film properties can be achieved, but the number of layers is limited to 7-11 layers
Solution Approach 1:
The patent creates a multi-functional die system where a single die structure simultaneously performs multiple extrusion functions through its array of extrusion ports. Each port can process different materials and produce different layer configurations, allowing the system to generate diverse film properties and high layer counts from one unified device rather than requiring separate dies for each layer configuration
Data Source
AI summary
A method of making thin, annular multilayer coextruded films uses a layer sequence repeater module that includes a cell formed of a plurality of thin annular disks stacked on top of each other in an axial direction of the co-extrusion die. Each disk includes a plurality of openings aligned with openings in the adjacent disks, thus forming multiple inner and outer melt passages. At least one cell of the layer sequence repeater module includes at least one first cap disk, at least one second cap disk, at least one distribution disk, at least one repeater disk and at least one spreader disk. The layer sequence repeater module may be a separately assembled and individually removable module of the co-extrusion die. Alternatively or additionally, the layer sequence repeater module may be incorporated into a module of the co-extrusion die.