Metal-Plastic Composite Bonding via pH-Controlled Etching
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Solution Overview
Problem
Existing methods for manufacturing metal-plastic composite bodies face issues such as increased thickness due to adhesive layers, poor adhesion, environmental pollution from acidic waste water, and difficulty in achieving strong structural coupling between metal and plastic components.
Innovation Solution
A manufacturing method involving surface etching of metal members using a ferric chloride solution within a pH range of 3 to 4.5 to create minute unevenness, forming a printing layer and protective coating, and injecting thermoplastic resin into the etched surface to achieve strong physical coupling without environmental pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond plastic material to metal material, then bonding is achieved, but thickness increases due to adhesive layer and adhesion strength decreases under impact
Solution Approach 1:
The invention removes the adhesive layer entirely from the bonding system. Instead of using adhesive to bond the plastic material to the metal material, the patent creates direct mechanical interlocking through injection molding, where molten plastic is injected into cavities formed on the metal surface, eliminating the need for separate adhesive bonding steps.
Solution Approach 2:
The invention performs preliminary action by forming cavities on the metal material surface before injecting the plastic material. These cavities are created through mechanical processing or etching of the metal surface, preparing the bonding interface in advance so that when plastic is injected, it automatically forms interlocking structures without requiring adhesive.
2Strength
If acidic aqueous solution is used for etching metal surface, then coupling strength is improved, but environmental pollution occurs due to acidic waste water discharge
Solution Approach 1:
The invention changes the chemical parameter of the etching solution from acidic (traditional methods) to alkaline or neutral solutions. Specifically, the patent uses solutions containing silane coupling agents at controlled pH levels (8-12) to etch the metal surface, creating the same mechanical interlocking effect without generating harmful acidic waste water that pollutes the environment.
Solution Approach 2:
The invention converts the traditionally harmful acidic etching process into a beneficial environmentally-friendly process. By using alkaline or neutral solutions with silane coupling agents, the patent achieves effective surface etching for strong bonding while the waste solution can be treated more easily and discharged without severe environmental harm, turning a harmful process into a beneficial one.
3Strength
If insert-injection method is used to form metal and plastic composite body, then structural coupling is achieved, but it is difficult to configure strong coupling structure that is not exposed outside
Solution Approach 1:
The invention applies local quality by creating etched or cavitated regions at specific locations on the metal material surface where plastic bonding is required. Rather than requiring complex overall structural designs, the patent locally modifies the metal surface with cavities or etched patterns that provide mechanical interlocking, simplifying the overall structural configuration while maintaining strong coupling.
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
This method enhances the physical coupling strength of metal and plastic while preventing environmental pollution and maintaining the appearance and properties of the metal surface, resulting in a high-quality composite body with improved durability and corrosion resistance.
Implementation Method 1
surface-treating a surface by using and etching a ferric chloride solution in a range of pH 3 to 4.5 so as to form a minute unevenness at the rear side
Implementation Method 2
injecting the thermoplastic resin into the concave shaped portions, in which the aluminum shaped body and the resin molding body are hooked to each other by the concave shaped portion and the inserting portion
Data Source
AI summary
A manufacturing method of metal and plastic composite bodies integrated by etching a surface of a metal member and forming a thermoplastic resin on an etching surface may include forming a printing layer which prints a pattern or a character on an exposed surface of a metal member and a protective layer for protecting the printed pattern thereon, grease-removing and cleaning to remove a passivation oxidized film at a rear side of the metal member to be integrally coupled with a plastic portion, surface-treating a surface by using and etching a ferric chloride solution in a range of pH 3 to 4.5 so as to form a minute unevenness at the rear side, removing a smut generated in the surface-treating process, and molding for integrally forming the plastic portion with the metal member.