Multi-stage Resin Etching Without Swelling

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Solution Overview

Problem

Existing resin etching methods using chromic acid are environmentally hazardous and costly, and alternative methods like permanganic acid-based techniques face issues with decomposition and require a swelling step that can lead to low adhesion in plating.

Innovation Solution

A two-stage etching process using permanganic acid or its salts, followed by activation with sulfuric acid or other acids, eliminates the need for a swelling step and enhances adhesion by repeatedly performing these steps, allowing for efficient etching without decomposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If chromic acid is used for resin etching to enhance adhesion, then adhesion is improved, but environmental harm and operational cost increase

Engineering Contradiction:
ImproveadhesionVSAvoidenvironmental harm
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters by replacing chromic acid with permanganic acid as the oxidizing agent, and introduces specific activating agents (sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, methanesulfonic acid, hydrogen peroxide, peroxodisulfate, periodic acid, perchloric acid, or perbromic acid) to control the etching process. This parameter substitution eliminates hexavalent chromium while maintaining etching effectiveness and adhesion enhancement.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs permanganic acid which can be easily disposed of and decomposes into harmless manganese dioxide and oxygen, replacing the environmentally persistent and hazardous chromic acid. The activating agents are used in controlled amounts and can be neutralized or decomposed, making the process more environmentally friendly and cost-effective.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If permanganic acid is used for resin etching to replace chromic acid, then environmental harm is reduced, but the oxidizing agent decomposes promptly under certain conditions

Engineering Contradiction:
Improveenvironmental harmVSAvoidoxidizing agent stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent performs preliminary activation of the permanganic acid oxidizing agent by treating the resin surface with specific activating agents before the main etching process. This preliminary action ensures the oxidizing agent is in an active state and less prone to decomposition during the etching process, improving reliability while maintaining environmental benefits.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The activating agents (sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, methanesulfonic acid, hydrogen peroxide, peroxodisulfate, periodic acid, perchloric acid, or perbromic acid) act as intermediaries that facilitate the action of permanganic acid on the resin surface. These intermediaries control the reaction rate and prevent premature decomposition, enhancing the stability and effectiveness of the oxidizing agent.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a swelling step is added to suppress decompostion of permanganic acid, then oxidizing agent stability is improved, but adhesion of plating decreases

Engineering Contradiction:
Improveoxidizing agent stabilityVSAvoidadhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent segments the etching process into distinct stages: (1) activation treatment with activating agents, (2) etching treatment with permanganic acid, and (3) neutralization and reduction treatment. This segmentation allows each step to be optimized independently, maintaining oxidizing agent stability while ensuring good adhesion through controlled etching without requiring a swelling step.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the chemical parameters by using specific activating agents and controlling the concentration and application method of permanganic acid. By adjusting these parameters, the process achieves stable oxidizing action without requiring resin swelling, thereby maintaining both oxidizing agent stability and plating adhesion.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If a multi-stage etching process is used to suppress decompostion, then oxidizing agent stability is improved, but process complexity increases

Engineering Contradiction:
Improveoxidizing agent stabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the etching process into three simple sequential stages: (1) activation treatment with activating agents, (2) etching treatment with permanganic acid, and (3) neutralization and reduction treatment. This segmentation makes the process more manageable and reliable while avoiding the need for complex swelling steps or multiple swelling-etching cycles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent ensures continuous useful action by immediately following the activation treatment with the etching treatment and then with neutralization, eliminating idle time and unnecessary steps. The continuous process flow reduces overall complexity while maintaining oxidizing agent stability through proper sequencing.

Inventive Principle:
Principle #20Continuity of useful action

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 achieves high adhesion and withstands severe heat shock tests, reducing environmental concerns and operational costs by suppressing oxidizing agent decomposition and eliminating the need for a swelling step.

Implementation Method 1

a step of treating the resin surface with a solution containing an oxidizing agent and adsorbing the oxidizing agent on the resin surface, wherein the oxidizing agent used is permanganic acid or a salt thereof

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

a step of activating the oxidizing agent adsorbed on the resin surface in the step (a), wherein the activation of the oxidizing agent is performed by a treatment with a solution containing one type or two or more types of activating agents selected from the group consisting of sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, methanesulfonic acid, hydrogen peroxide, peroxodisulfate, periodic acid, perchloric acid, and perbromic acid

Methodology Applied
Scientific EffectChemical activation: Catalysis

Data Source

PatentEP3633066B1Multi-stage resin surface etching method, and plating method on resin using same
Publication Date: 2023.09.13 JCU CORP

AI summary

A novel technique that is a resin etching technique without using chromic acid and can be operated at an industrial level is provided by a resin surface etching method characterized in that, in etching a resin surface, one set of the following steps (a) and (b) is performed two or more times without performing a resin swelling step: (a) a step of treating the resin surface with a solution containing an oxidizing agent and adsorbing the oxidizing agent on the resin surface, and (b) a step of activating the oxidizing agent adsorbed on the resin surface in the step (a).