Polyamide Battery Packaging Ink Adhesion via Amide Limit
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Solution Overview
Problem
Polyamide resin films containing ethylene bis-oleic acid amide used in battery packaging materials exhibit poor ink printing characteristics due to ink repulsion when heated, leading to incomplete printing and reduced printability, especially with pad printing methods.
Innovation Solution
Forming a battery packaging material with a base material layer made of polyamide resin containing either ethylene bis-stearic acid amide or ethylene bis-oleic acid amide, with the latter's content limited to 400 ppm or less, to improve ink adhesion and printability, and ensuring the ink is not repelled during the baking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ethylene bis-oleic acid amide is used as a water repellant in polyamide resin film, then surface wettability is adjusted and surface slippage is controlled, but ink printing characteristics deteriorate due to ink repulsion during baking
Solution Approach 1:
The patent changes the chemical parameter of the water repellant from ethylene bis-oleic acid amide to ethylene bis-stearic acid amide, which has different molecular structure and thermal properties. This parameter change maintains the water repellant function while preventing ink repulsion during baking, thus resolving the contradiction between surface wettability control and ink printing quality
Solution Approach 2:
The patent uses ethylene bis-stearic acid amide as a substitute that copies the water repellant function of ethylene bis-oleic acid amide but with improved ink compatibility. The substitute maintains the essential function (water repulsion and surface slippage control) while eliminating the harmful effect (ink repulsion)
2Loss of information
If a seal with printed characters is attached to the base material layer surface, then printing requirements are met, but thickness and weight of the battery packaging material increase
Solution Approach 1:
The patent extracts the printing function from a separate seal layer and integrates it directly into the base material layer surface. By enabling direct printing on the base material layer through proper surface treatment, the separate seal layer is eliminated, thus reducing both weight and thickness while maintaining printed character visibility
Solution Approach 2:
The patent merges the printing function with the base material layer by achieving direct printability through surface treatment. The printed characters are now part of the base material layer itself rather than being on a separate seal layer, combining multiple functions into one layer
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 solution enhances the ink printing characteristics on the surface of the battery packaging material, allowing for effective pad printing even after the baking step, reducing missing print areas and improving overall print quality.
Implementation Method 1
when a polyamide resin film containing ethylene bis-oleic acid amide as a water repellant is used in a base material layer, heat is applied in a baking step etc. after a battery element such as an electrolytic solution is encapsulated in a battery packaging material, whereby ethylene bis-oleic acid amide is bled out on a surface of a base material layer, and thus when the surface of the base material layer is printed with an ink by pad printing etc., an ink is repelled at the surface of the base material layer
Data Source
AI summary
A cell packaging material in which the substrate layer surface has excellent ink printing characteristics. Cell packaging material including a layered article provided with at least a substrate layer, a metal layer, and a heast-fusible layer in the stated order, the substrate layer being formed from a polyamide resin containing an ethylene-bis-stearic acid amide and an ethylene-bis-oleic acid amide.