Electrodeposition Coating

Definition and Overview

Electrodeposition coating is a coating method in which conductive metal parts are immersed in a paint solution and electrical energy is used to deposit the coating components. The formed coating film is generally heat-cured. It easily reaches fine details and recessed areas, and is used to achieve a finished appearance and protect metal accessories.

In apparel accessories, it may be applied to metal surfaces such as press fasteners, eyelets, and cap and close posts. Cationic electrodeposition often refers to a method in which the coating components deposit as cations, and it may simply be called electrodeposition, so the finish name should be confirmed in specifications.

Materials and Component Structure

Electrodeposition coating is not the material name of the part itself, but a finish applied to a metal surface. The parts to which it is applied are often made of metals such as brass, iron, or zinc-based alloys, and appearance and corrosion resistance vary depending on the combination of material, base treatment, and coating film.

In press fasteners, the head, spring or stud, eyelet, and washer may each receive a similar finish. However, since the material and surface treatment may differ by part, it is necessary to confirm the overall color tone and specifications of the set.

• Coating color and gloss
• Type of base metal
• Whether there is base treatment such as plating
• Color differences and lot differences between parts

Size Notation and Installation Method

Electrodeposition coating itself has no unique size notation. When selecting it as a press fastener or eyelet, judge by the dimensions and specifications of the finished part, such as head diameter, eyelet diameter, leg length, and compatible fabric thickness. Even with the same outer diameter, the suitable fabric thickness changes if the component structure or leg length differs.

Installation is performed using a die and anvil that match the part, with a hand press, treadle press, or air press. If the die shape or pressing pressure does not match, it can cause coating scratches, cracking, poor setting, or poor fit, so trial setting on the actual fabric is done before mass production.

Main Applications and Precautions

Metal accessories with electrodeposition coating are used on outerwear, pants, denim, bags, uniforms, and similar items where coordinated colors and a subdued surface feel are needed. Suitability for the application cannot be determined by the coating name alone, so selection should take into account frequency of use, washing, sweat, friction, and storage conditions.

If a short-leg part is used on thick fabric, it may not be set firmly enough; if a long-leg part is used on thin fabric, deformation or wobbling may occur. For highly stretchable fabrics, brushed fabrics, or fabrics with low weave density, check pull-out strength, including the use of pressing cloth or reinforcement interfacing.

If the coating film is scratched or chipped, corrosion or discoloration of the base metal may become noticeable. The effects of moisture, sweat, detergent components, and contact with other metals also depend on the material and base treatment, so corrosion resistance and washing tests should be considered according to product conditions.

Metal parts with electrodeposition coating do not eliminate reactions to metal detectors. For products that require needle detector compatibility, confirm the policy for detector response on the parts used in advance as part of production control. Also, being covered with electrodeposition coating does not mean the part is nickel-free.

Differences from Plating

Plating is a surface treatment that forms another metal layer on the surface of a metal. Electrodeposition coating, by contrast, is a finish that primarily forms a coating film from resin-based paint components. The two may look similar, but the properties of the film, the base, and the evaluation methods for durability differ.

Black nickel and similar terms indicate types of plating, whereas cationic electrodeposition indicates a coating method. When ordering, it is important not to judge by the color name alone, but to specify the material, base treatment, finishing method, gloss, and nickel-free requirements separately in the specifications.

Frequently Asked Questions