Chromium-Free Nickel Plating for Resin Adhesion

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Solution Overview

Problem

Existing methods for forming a surface-treated steel sheet for metal containers, particularly in the food and beverage industry, do not achieve sufficient adhesion between the steel sheet and the organic resin layer after forming processes like drawing or drawing-ironing, especially when chromium-free alternatives are sought.

Innovation Solution

A chromium-free organic resin coated surface-treated steel sheet is developed with a nickel plating layer having fine particles of 2 to 500 pieces/µm² and an average size of 0.05 to 0.7µm, formed using a nickel plating bath with low nickel ion concentration, and optionally including metallic tin, with an alloy layer of iron and nickel, and an oxygen compound like Zr, Ti, or Al applied between the steel sheet and the organic resin layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If chromium-free nickel plating is applied to steel sheet, then environmental safety is improved, but adhesion between steel sheet and organic resin layer after working deteriorates

Engineering Contradiction:
Improveenvironmental safetyVSAvoidadhesion between steel sheet and organic resin layer
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by creating an uneven surface structure with specific particle density (2-500 pieces/µm²) and average particle size (0.05-0.7 µm) on the nickel plating layer. This localized surface modification enhances adhesion of the organic resin layer to the chromium-free nickel plating, resolving the contradiction between environmental safety and adhesion reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the nickel plating surface by controlling particle density and average particle size within specific ranges. These parameter changes create an optimal surface morphology that improves resin adhesion while maintaining chromium-free composition, thus resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional nickel plating is applied to steel sheet, then adhesion between steel sheet and organic resin layer is improved, but environmental safety deteriorates due to chromium usage

Engineering Contradiction:
Improveadhesion between steel sheet and organic resin layerVSAvoidenvironmental safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates chromium from the plating composition, using only nickel-based plating. By removing the harmful chromium component while compensating with controlled nickel particle structure, the patent achieves both environmental safety and adequate adhesion performance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If island-like tin is formed on nickel plating, then adhesion at high temperature is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveadhesion at high temperatureVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex multi-step process involving tin plating and melting with a simpler nickel plating process that directly achieves the desired adhesion. The controlled nickel particle structure serves as a permanent adhesion promoter without requiring additional tin layers or high-temperature melting steps.

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

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 approach ensures excellent adhesion between the steel sheet and the organic resin layer even after forming processes, maintaining high peel strength and preventing resin peeling, thus enhancing the durability and performance of metal containers.

Implementation Method 1

nickel plating is applied to at least one-side surface of the surfaces of a steel sheet by coating

Methodology Applied
Scientific EffectElectroplating: Electroplating

Data Source

PatentEP2857557B1Surface-treated steel sheet for container having excellent processing adhesion to resin, method for manufacturing same, and can
Publication Date: 2019.10.23 TOYO KOHAN CO LTD
  • EP2857557B1 patent drawingFigure 1
  • EP2857557B1 patent drawingFigure 2
  • EP2857557B1 patent drawingFigure 3

AI summary

Provided is a container-use surface treated steel sheet which is manufactured without using chromium and exhibits excellent working adhesion with a coated organic resin, a method of manufacturing the container-use surface treated steel sheet, an organic resin coated surface treated steel sheet. The container-use surface treated steel sheet is a surface treated steel sheet where nickel plating is applied to at least one-side surface of surfaces of a steel sheet by coating, wherein nickel plating has a fine particle shape formed by fine particles which has particle density of 2 to 500 pieces/µm2 and having an average particle size of 0.05 to 0.7µm. The container-use surface treated steel sheet is also characterized in that a coating weight of the nickel plating of the container-use surface treated steel sheet is 0.1 to 12g/m2, metal tin is contained in coating of the nickel plating, and an amount of metal tin is 0. 05 to 0. 1g/m2. The organic-resin-coated surface treated steel sheet of the present invention is characterized in that an organic resin layer is formed on at least one surface of the container-use surface treated steel sheet. The metal can is formed by working the organic-resin-coated surface steel sheet.