Dual-Layer Oxygen Barrier Membranes for Scalable Roll-to-Roll Coating
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Solution Overview
Problem
Existing methods for manufacturing cellulose and chitin nanomaterial films are time-consuming and unsuitable for large-scale production, limiting their use in scalable, biodegradable barrier films with desirable oxygen permeation.
Innovation Solution
A dual layer coated membrane is developed using a roll-to-roll coating process, comprising a permeable base layer and a dual layer oxygen barrier film made of chitin and cellulose nanomaterials, with a roll-to-roll coating process that includes ultraviolet treatment and controlled drying to achieve a thickness ratio of at least 10:1 for the second layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If suspension casting or spray coating methods are used to manufacture cellulose and chitin nanomaterial films, then uniform thickness and barrier properties can be achieved, but the manufacturing process becomes time-consuming and unsuitable for large-scale production
Solution Approach 1:
The patent replaces traditional mechanical coating methods (spray coating, suspension casting) with a roll-to-roll coating system that uses controlled fluid delivery through a slot die. This substitution enables continuous manufacturing while maintaining uniform coating thickness through precise control of coating head geometry, substrate speed, and suspension flow rate, thereby resolving the contradiction between manufacturing precision and productivity.
Solution Approach 2:
The patent implements a continuous roll-to-roll coating process where the substrate moves continuously through the coating zone without interruption. The slot die delivers suspension continuously onto the moving substrate, and the coating is dried in-line, eliminating the batch processing steps inherent in spray coating and suspension casting. This continuous operation dramatically increases productivity while maintaining coating uniformity through consistent process parameters.
2Manufacturing precision
If spin coating is used to produce thin films, then uniform coating can be achieved, but it is not suitable for continuous large-area production
Solution Approach 1:
The patent segments the coating process into distinct functional zones: suspension delivery through a slot die, in-line drying, and winding. This segmentation allows each zone to be optimized independently - the slot die geometry controls coating thickness uniformity, the drying zone removes solvent, and the winding system collects the coated substrate. This modular approach enables continuous large-area production while maintaining the coating uniformity characteristic of spin coating.
Solution Approach 2:
The patent transitions from the two-dimensional spin coating process (rotating disk) to a three-dimensional continuous belt system where coating occurs along the length of the moving substrate. The slot die creates a controlled coating window that spans the width of the substrate, enabling uniform coating across large areas. This dimensional change from rotational to linear motion fundamentally enables scalability while preserving coating quality.
3Strength
If cellulose and chitin nanomaterials are used as neat materials for barrier films, then high tensile strength and crystallinity can be achieved, but the inability to melt-process limits manufacturability
Solution Approach 1:
The patent uses water as an intermediary medium to process cellulose and chitin nanomaterials. These biopolymers are suspended in water to form processable slurries that can be applied by roll-to-roll coating. The water acts as a temporary carrier that enables manipulation and deposition of the nanomaterials, which would otherwise be impossible to process due to their inability to melt. After coating, the water evaporates during the in-line drying process, leaving the desired nanomaterial film with high tensile strength and crystallinity.
Solution Approach 2:
The patent changes the physical state and processing parameters of cellulose and chitin nanomaterials by dispersing them in aqueous suspension rather than attempting to melt-process them. The suspension concentration, viscosity, and flow characteristics are carefully controlled to enable smooth coating deposition. During drying, water evaporates and the nanomaterials reorganize into high-crystallinity structures, achieving both processability and high mechanical properties through parameter control rather than thermal processing.
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 membrane achieves an oxygen permeation of less than 20 cm³ μm/m²/day/kPa at 23°C and 50% relative humidity, significantly improving scalability and performance compared to spray coating methods.
Implementation Method 1
a roll-to-roll coating process that includes ultraviolet treatment
Data Source
AI summary
An exemplary embodiment of the present disclosure provides a membrane including a supporting base layer, which can be permeable, and a dual layer oxygen barrier film disposable over the supporting base layer. The supporting barrier film can include a polymeric or paper-based material. The dual layer oxygen barrier film can include a chitin material and a cellulosic material. The cellulosic material of the dual layer oxygen barrier film can be the same material as the permeable membrane or can be any other cellulosic material.