VUV-Curable Oxide Barrier Layer on Flexible Substrates
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Solution Overview
Problem
Current methods for producing single barrier layers on flexible polymeric substrates result in high water vapor transmission rates (WVTR) due to process-related defects, necessitating multiple laminated layers, which increase thickness, reduce flexibility, and increase manufacturing costs.
Innovation Solution
A method involving coating a flexible polymeric substrate with a VUV-curable coating material under an inert gas atmosphere, followed by solvent removal and curing with VUV radiation in an oxygen-inert gas atmosphere with controlled oxygen concentration, to form a single oxide barrier layer with reduced defects and high WVTR barrier performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple barrier layers are laminated to achieve low WVTR values, then water vapor barrier performance is improved, but film thickness increases and flexibility decreases
Solution Approach 1:
The patent changes the chemical composition and structure parameters of the barrier layer by using fluorinated cyclic carbonate compounds with specific molecular structures (formula 1) and controlling the glass transition temperature (Tg) to be -50°C to 0°C. This parameter optimization enables a single layer to achieve WVTR ≤ 10^-4 g/m²/day without requiring multiple laminated layers, thus reducing total film thickness while maintaining high barrier performance.
Solution Approach 2:
The patent creates a composite barrier layer by combining fluorinated cyclic carbonate compounds with specific additives and using multi-step coating processes. The composite structure incorporates the cyclic carbonate compound as the base resin with controlled Tg, achieving superior barrier properties in a single layer that eliminates the need for multiple separate barrier layers.
2Reliability
If multiple barrier layers are laminated to achieve high barrier performance, then water vapor transmission is reduced, but manufacturing complexity and costs increase
Solution Approach 1:
The patent merges the functions of multiple barrier layers into a single barrier layer by using fluorinated cyclic carbonate compounds with optimized molecular structures and Tg ranges. This consolidation reduces the number of coating and lamination steps required, simplifying the manufacturing process while achieving the same or better barrier performance (WVTR ≤ 10^-4 g/m²/day).
Solution Approach 2:
By changing the chemical parameters of the barrier material (using fluorinated cyclic carbonate compounds with specific Tg ranges and molecular structures), the patent achieves high barrier performance in a single layer, thereby reducing manufacturing complexity associated with multiple layer lamination processes.
3Ease of manufacture
If conventional coating materials are used to form barrier layers, then processing is simpler, but process-related defects occur leading to high WVTR values
Solution Approach 1:
The patent uses fluorinated cyclic carbonate compounds with specifically controlled glass transition temperatures (-50°C to 0°C) and defined molecular structures (formula 1). These parameter changes in material composition eliminate process-related defects such as OH group formation that occur with conventional materials, achieving both ease of manufacture and high reliability with WVTR ≤ 10^-4 g/m²/day.
Solution Approach 2:
The patent employs a single-layer structure that is discarded if defects occur, rather than attempting to repair complex multi-layer laminates. The simplified single-layer design using fluorinated cyclic carbonate compounds makes the entire coating process more robust and less prone to defects, improving both ease of manufacture and reliability.
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 achieves a WVTR of ≤10^-2 gm^-2 d^-1 in a single layer, enabling WVTRs ≤10^-4 gm^-2 d^-1 in a two-layer laminate, while maintaining flexibility and reducing manufacturing costs by minimizing the number of layers required.
Implementation Method 1
The VUV-curable coating material is irradiated with VUV radiation with a wavelength of 100 nm to 250 nm
Implementation Method 2
The concentration of oxygen mixed with the inert gas in the oxygen-inert gas atmosphere is selected such that the oxygen partially absorbs the radiation, thus slowing down the curing process
Implementation Method 3
photoconversion can be carried out so slowly that both the inward diffusion of oxygen as a reactant in the photochemical conversion is possible
Implementation Method 4
the outward diffusion of reaction products such as ammonia can take place
Implementation Method 5
photoconversion can be carried out so slowly that both the inward diffusion of oxygen as a reactant in the photochemical conversion is possible
Data Source
Figure 1
AI summary
The invention relates to a method for producing a single barrier layer on a flexible polymeric substrate. The method comprises the following steps, to be carried out under an inert gas atmosphere: providing a flexible polymeric substrate; coating the flexible polymeric substrate with a coating agent consisting of a solvent and a VUV-curable coating material; removing the solvent; adjusting an oxygen content of 1 10-4 to 2 volume percent in an oxygen inert gas atmosphere; and irradiating the VUV-curable coating material with vacuum ultraviolet radiation having a wavelength of 100 nm to 250 nm under the oxygen inert gas atmosphere to cure an oxide layer on the flexible polymeric substrate.