Copper Plating Bath for Printing Cylinders Preventing Self-Annealing
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Solution Overview
Problem
Existing copper plating processes for gravure printing cylinders face challenges in maintaining stable hardness, particularly due to self-annealing issues, which affect the quality of engraving and the longevity of diamond styli, and are limited by the solubility and anode polarization in copper sulphate based electrolytes.
Innovation Solution
A copper plating bath comprising copper ions, methanesulphonate ions, chloride ions, an organosulphur compound, and a polyether compound is used to deposit a copper layer with stable hardness, preventing self-annealing and allowing high-speed plating for both partially and fully immersed cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If copper plating is performed using conventional copper sulphate based electrolytes, then plating process is simple and cost-effective, but the deposit exhibits self-annealing that reduces hardness over time
Solution Approach 1:
The patent changes the chemical composition parameters of the plating electrolyte by replacing copper sulphate based electrolytes with copper methanesulphonate based electrolytes, and adjusts additive concentrations (organosulphur compounds at 1-100 mg/l, polyether compounds at 1-1000 mg/l) to control self-annealing and maintain hardness stability between 200-240 HV
Solution Approach 2:
The patent uses a composite additive system combining organosulphur compounds (such as alkoxythio compounds) with polyether compounds (such as polyethylene glycol) to achieve synergistic effects that prevent self-annealing and maintain deposit hardness, rather than relying on single additive types
2Manufacturing precision
If copper deposit hardness is increased above 240 HV to improve engraving quality, then engraving definition improves, but diamond stylus lifetime is reduced
Solution Approach 1:
The patent precisely controls the hardness parameter within the optimal range of 200-240 HV by adjusting electrolyte composition and additive concentrations, achieving sufficient engraving definition while preventing excessive hardness that would damage diamond styli
3Productivity
If plating immersion depth is increased to reduce plating time, then productivity improves, but deposit characteristics are affected by current fluctuations and composition differences
Solution Approach 1:
The patent modifies electrolyte composition parameters (using copper methanesulphonate instead of copper sulphate, adjusting chloride ion concentration to 10-200 mg/l) to enable stable deposit characteristics even at high immersion depths and fast plating rates, compensating for current fluctuations and composition gradients
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 provides copper deposits with consistent hardness between 200-240 HV, preventing self-annealing and enabling high-speed plating, thus improving engraving quality and reducing equipment wear, while overcoming limitations of copper sulphate based electrolytes.
Implementation Method 1
a copper plating bath for depositing a copper layer onto a printing cylinder
Implementation Method 2
the deposit self-anneals at room temperature and the hardness of the copper deposit falls
Data Source
AI summary
The present invention is directed to an improved copper plating bath for depositing a copper layer onto a printing cylinder, the copper plating bath comprising: (a) a source of copper ions; (b) a source of methane sulphonate ions; (c) a source of chloride ions; (d) an organosulphur compound having the formula R—S—R′—SO3−X+ or X+—O3S—R′—S—R—S—R′—SO3—X+, wherein R is alkyl, hydroxyalkyl or alkyl ether, R′ is a C2–C4 alkyl group, and X+ is a cation; and (e) a polyether compound and method of using the same. The copper plating bath produces a plating deposit that has a stable hardness and is free from self-annealing during high speed plating.