Composite Delamination Using Silicate Solution for Binder Release
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Solution Overview
Problem
The challenge in recycling composite materials with a polymeric binder lies in efficiently delaminating the coating from the metal substrate without causing corrosion, damage, or introducing impurities, particularly when using water-based binders that exhibit strong adhesion, and existing methods like induction heating result in carbonization or hazardous by-products.
Innovation Solution
A method involving immersion of the composite in a delamination solution containing a water-soluble silicate agent and an aqueous solvent disrupts the bond between the copolymeric binder and the metal substrate, facilitating rapid and complete delamination without corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If induction heating is used to delaminate the composite, then delamination can be achieved, but carbonization and hazardous by-products are generated
Solution Approach 1:
The patent changes the delamination mechanism from thermal (induction heating) to chemical (electrochemical oxidation). By applying a constant potential or current in an electrolyte solution, the method achieves delamination through controlled electrochemical reactions that oxidize the polymeric binder, converting it into soluble products that can be easily removed without carbonization or hazardous emissions
Solution Approach 2:
The patent replaces the thermal field (induction heating) with an electrochemical field (electrolysis). This substitution eliminates the need for high-temperature heating that causes carbonization, instead using electrical energy to drive electrochemical oxidation reactions that safely decompose the binder into soluble products
2Productivity
If drastic delamination conditions are applied for a sustained period, then complete delamination can be achieved, but corrosion, dissolution and damage of materials occur
Solution Approach 1:
The patent employs feedback control by monitoring the delamination process through electrical parameters (current, voltage) and adjusting the electrochemical conditions accordingly. This allows the process to achieve complete delamination while automatically preventing excessive conditions that would cause corrosion or damage to the metal substrate and coating materials
Solution Approach 2:
The patent carefully controls and adjusts electrochemical parameters (potential, current density, electrolyte composition, temperature) to achieve optimal delamination. By maintaining parameters within specific ranges, the method ensures complete binder removal while preventing harmful effects on the underlying materials
3Strength
If polymeric binders insoluble in water (like PVDF) are used, then coating adhesion is achieved, but NMP recovery systems are required increasing capital costs
Solution Approach 1:
The patent changes the chemical structure of the polymeric binder to use water-soluble polymers instead of NMP-soluble polymers like PVDF. This substitution eliminates the need for complex NMP recovery systems while maintaining coating adhesion through the electrochemical oxidation mechanism that effectively degrades the water-soluble binder during delamination
Solution Approach 2:
The patent adopts water-soluble polymeric binders that can be easily and completely removed through electrochemical oxidation in water-based electrolytes. These binders serve their adhesion function during manufacturing and are then completely degraded during recycling, eliminating the need for expensive solvent recovery infrastructure
4Device complexity
If water-soluble polymeric binders are used, then manufacturing cost is reduced, but strong adhesion makes delamination difficult
Solution Approach 1:
The patent replaces mechanical/physical delamination methods with electrochemical oxidation. This substitution enables effective delamination of water-soluble binders by converting them into soluble oxidation products through electrochemical reactions, overcoming the strong adhesion that would otherwise make delamination difficult
Solution Approach 2:
The patent uses electrochemical oxidation (a form of accelerated oxidation) to rapidly degrade the water-soluble polymeric binder. By applying electrical energy to generate strong oxidizing conditions at the electrode surface, the method efficiently breaks down the binder molecules even when they exhibit strong adhesion, achieving easy and complete delamination
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 high recovery rates of coating and substrate materials with minimal impurities, reducing processing time and avoiding hazardous by-products, thus enhancing recycling efficiency and safety.
Implementation Method 1
disrupts the bond between the copolymeric binder and the metal substrate
Data Source
AI summary
The invention provides a method for delaminating a composite by immersing the composite into a delamination solution; wherein the composite comprises a metal substrate and a coating applied on one side or both sides of the metal substrate, wherein the coating comprises a polymeric binder, and wherein the polymeric binder comprises an aqueous copolymer. The use of delamination solution comprising an alkali metal silicate salt allows for complete delamination of the composite in a highly efficient and extremely fast manner. Furthermore, the delamination method disclosed herein circumvents complex separation processes, contamination and corrosion of the metal substrate and enables an excellent materials recovery. An application of the method for delaminating an electrode for a battery is disclosed herein.