Water-Based Extrusion Primer for Low-Weight Metal-Polyolefin Bonding
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Solution Overview
Problem
Existing extrusion primers for bonding metal surfaces with polyolefin layers are tacky, require high application weights, and pose health risks due to organic solvent use, and fail to adhere well to metals like aluminum.
Innovation Solution
An aqueous coating composition comprising a copolymer formed by reacting catechol or its derivative with polyethyleneimine is applied to metal, polyethylene terephthalate, or polyamide substrates, followed by drying and applying a polyolefin melt, to create a multilayer laminate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If isocyanate-containing polymers solved in organic solvents are used as extrusion primers, then adhesion to metal surfaces is improved, but health risks increase due to organic solvent release
Solution Approach 1:
The patent changes the solvent parameter from organic solvents (ethyl acetate) to water as the dissolution medium. The copolymer is specifically designed to be water-soluble, transforming the primer from an organic solvent-based system to an aqueous system, thereby eliminating health risks while maintaining adhesion performance through the catechol-polyethyleneimine copolymer structure
Solution Approach 2:
The patent replaces expensive and harmful organic solvents with water, which is inexpensive and harmless. The water-based primer can be applied and then the water evaporates, leaving the adhesive copolymer layer. This substitution eliminates the need for expensive organic solvents and their associated health risks
2Strength
If tacky polymers are used as extrusion primers, then adhesion is improved, but the substrate cannot be rewound and requires inline processing
Solution Approach 1:
The patent changes the surface property parameter from tacky to non-tacky by using the catechol-polyethyleneimine copolymer. This copolymer provides strong adhesion to metal surfaces through catechol group coordination with metal oxides, yet forms a non-tacky surface that allows easy rewinding and offline processing, resolving the contradiction between adhesion strength and operational flexibility
3Strength
If high application weight (0.2 to 1 g/m2) is used, then acceptable adhesion values are reached, but material consumption increases
Solution Approach 1:
The patent changes the chemical structure parameters of the primer polymer to enhance its adhesion efficiency. The catechol groups provide strong coordination bonding with metal oxide surfaces, while the polyethyleneimine backbone provides multiple attachment points. This molecular design allows achieving excellent adhesion at very low application weights (0.01-0.1 g/m2), reducing material consumption by an order of magnitude compared to conventional primers
4Strength
If conventional primers are used on metal surfaces, then adhesion varies, but they fail to adhere well to aluminum surfaces
Solution Approach 1:
The patent applies local quality by designing the copolymer with specific functional groups (catechol) that have affinity for metal oxide surfaces. The catechol groups specifically target and bond with aluminum oxide and other metal oxide surfaces, providing reliable and consistent adhesion across different metal substrates. This localized functional group design ensures predictable performance on metal surfaces while the polyethyleneimine backbone provides general polymer properties
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 provides a tack-free, health-safe bonding process with improved adhesion between metal and polyolefin layers, eliminating the need for organic solvents and achieving strong laminate bonds.
Implementation Method 1
applying an aqueous coating composition comprising at least one copolymer obtained by reacting at least one compound which is catechol or a derivative thereof with at least one polyethyleneimine, onto the surface of the metal, polyethylene terephthalate, polypropylene or polyamide substrate
Implementation Method 2
subsequently drying for up to 10 minutes in order to obtain a coating layer
Data Source
AI summary
The invention relates to a method of manufacturing a multilayer laminate, the multilayer laminate obtained by the method according to the invention and to forming an extrusion primer for making the multilayer laminate using an aqueous coating composition comprising at least one specific copolymer.