Manganese Etching Bath Palladium Control for Resin Plating

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Solution Overview

Problem

Acidic etching baths containing manganese, which are alternatives to chromic acid mixtures to avoid toxic hexavalent chromium, suffer from reduced etching performance during continuous use due to palladium accumulation, necessitating a method to maintain stable etching performance.

Innovation Solution

A resin plating method that uses an acidic etching bath with manganese, controls the palladium concentration at 100 mg/L or less by methods such as removing palladium adsorbed on jigs, cathodic electrolysis, or iodide addition to the bath, ensuring consistent etching performance over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an acidic etching bath containing manganese is used as an alternative to chromic acid mixture, then environmental safety and work environment are improved, but etching performance is significantly reduced during continuous use due to palladium accumulation

Engineering Contradiction:
Improvetoxicity of etching solutionVSAvoidetching performance stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention extracts and removes accumulated palladium from the etching bath through multiple methods: (1) removing palladium adsorbed on jigs by immersing them in palladium-removing treatment solutions containing nitric acid, persulfates, hydrogen peroxide, or chelating compounds; (2) reducing palladium concentration by cathodic electrolysis to deposit metallic palladium on the cathode; and (3) reducing palladium concentration by iodide addition to form precipitates. This extraction of the harmful accumulated substance resolves the contradiction between environmental safety and performance stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical parameters of the etching bath by controlling palladium concentration at 100 mg/L or less through the described removal methods. By actively managing and adjusting the palladium concentration parameter, the system maintains stable etching performance while using the environmentally friendly manganese-based etching solution.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If an acidic etching bath containing manganese is used, then environmental impact is reduced, but etching power is significantly reduced during continuous use

Engineering Contradiction:
Improveenvironmental impact of waste liquidVSAvoidetching power
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The invention ensures continuous etching power by implementing ongoing palladium removal measures during continuous use. The systematic approach of removing palladium from jigs, reducing concentration through electrolysis, and preventing accumulation through iodide addition maintains the etching bath's effectiveness throughout continuous operation, eliminating the decline in etching power.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

By actively controlling and adjusting the palladium concentration parameter to remain at 100 mg/L or less through continuous removal methods, the invention maintains optimal etching power levels throughout continuous use, resolving the contradiction between environmental benefits and productive capability.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the etching process is repeated continuously, then production efficiency is improved, but palladium accumulates in the etching bath reducing etching performance

Engineering Contradiction:
Improvecontinuous plating treatment capabilityVSAvoidetching performance consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention implements a feedback control system where palladium accumulation is continuously monitored and addressed through removal measures. By measuring or estimating palladium concentration and applying corrective actions (removal from jigs, electrolysis, iodide addition) to maintain concentration at 100 mg/L or less, the system ensures consistent etching performance throughout continuous production operations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention discards accumulated palladium from the etching bath through multiple recovery methods: removing adsorbed palladium from jigs, depositing palladium on cathodes through electrolysis, and precipitating palladium through iodide addition. This continuous discarding and recovery process maintains etching performance consistency during continuous production.

Inventive Principle:
Principle #34Discarding and recovering

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 maintains excellent etching performance and prevents a reduction in etching power even during prolonged continuous use, enabling the formation of high-quality plating films on resin materials.

Implementation Method 1

an etching step in which an article comprising a resin material is used as an object to be treated and is subjected to etching using an acidic etching bath containing manganese

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a method for reducing the palladium concentration in an etching bath by cathodic electrolysis

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 3

a method for removing palladium adsorbed on a jig

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3168326B2Resin plating method
Publication Date: 2023.09.20 OKUNO CHEM IND CO LTD

AI summary

The present invention provides a resin plating method using an etching bath containing manganese as an active ingredient, the method being capable of maintaining stable etching performance even during continuous use. The resin plating method includes: an etching step, which uses a resin material-containing article as an object to be treated and etches the article using an acidic etching bath containing manganese; a catalyst application step, which uses palladium as a catalyst metal; and an electroless plating step; and the method further includes a step of maintaining the palladium concentration in the acidic etching bath at 100 mg/L or less.