Overview
ISO 22775:2004 is an international standard developed by ISO/TC 216 and CEN/TC 309 that specifies test methods to evaluate the corrosion resistance of metallic accessories used in footwear. The standard provides two practical methods for assessing the propensity of metal surfaces on footwear components to undergo visual changes such as tarnishing or corrosion. These tests help manufacturers and quality control laboratories ensure durability and maintain aesthetic quality in footwear metal parts exposed to atmospheric pollution or salt water.
The two key test methods are:
- Method 1: Sulfide Tarnishing – Measures susceptibility to discoloration from atmospheric hydrogen sulfide.
- Method 2: Salt Water Corrosion – Assesses corrosion caused by exposure to salt water.
Key Topics
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Corrosion Resistance Definition: The ability of metal accessories to resist visual alterations or degradation due to chemical attacks by pollution or salt water.
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Test Method 1 - Sulfide Tarnishing
- Specimens are exposed to a moist atmosphere with low hydrogen sulfide concentration for 1 hour.
- A subjective visual comparison between exposed and reference specimens identifies discoloration using a 1–5 grading scale, where 5 indicates no change and 1 indicates very marked change.
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Test Method 2 - Salt Water Corrosion
- The specimen is wrapped in sodium chloride-saturated cotton lawn and sealed in a polyethylene bag for 24 hours at room temperature.
- Post-exposure, both specimen and cotton lawn are rinsed and dried, followed by visual grading for corrosion or staining on a 1–5 scale similar to Method 1.
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Apparatus and Materials
Method 1 requires a hydrogen sulfide generator (such as a Kipps generator), sealed glass vessels, and fume cupboard due to toxic gas handling.
Method 2 requires sodium chloride solution, cotton lawn fabric, and sealable polyethylene bags.
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Specimen Preparation
Test samples should include the most corrosion-prone areas; cut edges are sealed with epoxy. Both exposed and reference specimens are required for accurate comparison.
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Assessment and Reporting
Visual grading is subjective-recommended to be conducted by multiple persons. The test report documents method used, specimen description, visual grading outcomes, and any notable test deviations or incidents.
Applications
ISO 22775:2004 is crucial for footwear manufacturers, accessory suppliers, and quality assurance labs aiming to:
- Ensure metallic shoe components withstand environmental conditions without significant corrosion or tarnishing.
- Maintain product aesthetics and consumer satisfaction by preventing premature discoloration and deterioration.
- Evaluate material choices and surface treatments for metal accessories under simulated atmospheric or marine exposure.
- Support compliance with quality standards in international footwear markets.
- Perform consistent and standardized corrosion resistance testing to facilitate product comparisons and procurement decisions.
This standard is applicable to a wide range of shoe metal accessories such as buckles, eyelets, zippers, and decorative elements.
Related Standards
For comprehensive footwear testing, ISO 22775 can be used alongside other ISO standards such as:
- ISO 20882 – Footwear resistance to water penetration.
- ISO 20861 – Mechanical testing of footwear components.
- ISO 16186 – Chemical tests for leather and related materials.
- ISO 20344 – General test methods for footwear.
Complementing corrosion resistance tests with mechanical and chemical standards assists manufacturers in delivering durable and high-quality footwear products that meet consumer and regulatory demands globally.
By adhering to ISO 22775:2004, the footwear industry gains an essential tool for evaluating and guaranteeing the corrosion performance of metallic components, optimizing product longevity, and preserving visual appeal under varying environmental exposures.
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