Metallization Inhibitor for Galvanic Racks
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Solution Overview
Problem
Existing galvanic metallization processes face challenges in preventing the metallization of plastic frames coated with PVC Plastisol during chromium (VI)-free etching solutions, as previous solutions involving sulphur derivatives or organosulphur compounds have proven inefficient.
Innovation Solution
Incorporating specific sulphur-based thiols, such as octyl mercaptan, n-octadecyl-3-mercaptopropionate, and bis-phenyl-1,4-thiol, directly into the PVC Plastisol formulation during the plasticization of electroplating frames to inhibit metallization effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chromium (VI) is used in mordanting to attack PVC Plastisol and inhibit frame metallization, then metallization inhibition is effective, but carcinogenicity and environmental harm increase
Solution Approach 1:
The patent changes the chemical composition parameter of the Plastisol coating by incorporating specific organosulphur compounds (thiols, sultones, or thioesters) at concentrations of 0.1-10% by weight. This chemical parameter modification enables the coating to resist metallization by chrome-free etching solutions without requiring carcinogenic chromium (VI), thus resolving the contradiction between effectiveness and environmental safety
Solution Approach 2:
The organosulphur compounds act as intermediary substances between the PVC Plastisol and the chrome-free etching solution. These compounds modify the coating's chemical properties to provide metallization resistance, serving as a mediator that enables effective inhibition without direct contact between the frame and harmful chromium (VI)
2Object-affected harmful factors
If chrome-free etching solutions are used to eliminate carcinogenicity, then environmental safety improves, but metallization inhibition of PVC Plastisol becomes ineffective
Solution Approach 1:
The patent modifies the chemical parameters of the Plastisol coating by adding specific organosulphur compounds (thiols, sultones, or thioesters) at optimized concentrations. This parameter change enables the coating to maintain metallization resistance when used with chrome-free etching solutions, resolving the contradiction between environmental safety and process effectiveness
Solution Approach 2:
The patent creates a composite coating system combining PVC Plastisol with organosulphur compounds. This composite material exhibits enhanced chemical resistance properties that enable it to withstand chrome-free etching solutions while maintaining metallization inhibition, thus resolving the contradiction between using safe etching agents and maintaining process effectiveness
3Ease of operation
If PVC Plastisol is used to coat and electrically isolate the frame, then electrical isolation is achieved, but the frame becomes susceptible to metallization with chrome-free etching solutions
Solution Approach 1:
The patent develops a composite coating material combining PVC Plastisol with organosulphur compounds. This composite maintains the electrical isolation properties of PVC while adding metallization resistance through the sulphur-containing compounds, thus resolving the contradiction between ease of electrical isolation and resistance to metallization
Solution Approach 2:
The patent modifies the compositional parameters of the Plastisol coating by incorporating 0.1-10% by weight of organosulphur compounds. This parameter change transforms the coating's chemical properties to provide metallization resistance while preserving its electrical isolation function, resolving the contradiction between these two requirements
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 use of these thiols in the PVC Plastisol formulation ensures that the electroplating frames remain metallization-free during the process, even with chrome (VI)-free etching solutions, as demonstrated by experimental tests showing complete inhibition of frame metallization without additional treatments.
Implementation Method 1
Incorporating specific sulphur-based thiols, such as octyl mercaptan, n-octadecyl-3-mercaptopropionate, and bis-phenyl-1,4-thiol, directly into the PVC Plastisol formulation during the plasticization of electroplating frames to inhibit metallization effectively
Implementation Method 2
To avoid that the entire frame is also metallized together with the items subjected to metallization, it must be electrically and chemically isolated, typically by coating it with PVC Plastisol
Implementation Method 3
components of plastic material are subjected to a chemical metallization treatment in a galvanic plant, through which one or more layers of metals (for example, copper, nickel and chromium) are deposited by an electrolytic process on plastic material details
Data Source
AI summary
The metallization of a metallic rack employed in galvanic metallization processes of plastic material items, coated by immersion in PVC Plastisol, is inhibited thanks to the fact that PVC Plastisol is mixed with a C8-C18 thiol selected from octyl mercaptan, nonyl mercaptan, decyl mercaptan, n-octadecyl-3-mercaptopropionate, isooctyl-3-mercaptopropionate, n-octyl- mercaptopropionate, dodecyl-3-mercaptopropionate, tridecyl-3-mercaptopropionate, palmityl mercaptan, bis- phenyl-1,4-thiol.