Nickel-free

Definition and Overview

Nickel-free is a specification that indicates consideration for nickel in the materials and surface treatment of metal accessories. Since nickel is considered one cause of metal allergies, it is evaluated for clothing and fashion accessories that come into frequent contact with the skin.

However, this label does not guarantee that no nickel is contained in any parts or that no allergic reaction will occur in all people. Confirm the target parts and verification method in the supplier’s specification sheet.

Material and Part Combinations

A press fastener is composed of multiple metal parts, such as the outer cap, the socket side, the stud side, and the stud on the back side. An eyelet may also be used in combination with the eyelet body and washer. When nickel-free is required, it is important to check not only the visible parts but the entire component set.

Some products use a base material such as brass, iron, or zinc alloy with a surface treatment that does not use nickel. On the other hand, the base material, plating undercoat, finish, and spring section may differ, so the color of the appearance alone cannot be used to judge.

• The items to confirm are all parts that make up the product, such as the cap, spring, stud, eyelet post, and washer.
• Nickel-free does not necessarily mean the same thing as nickel plating-free.
• Also confirm how the product is handled if the base material is exposed due to plating wear or scratches.

Size Description and Installation Method

The size of a press fastener is generally indicated by the outer diameter of the cap or by a standard number. Eyelets are indicated by inner diameter, outer diameter, foot length, and other measures, but the notation varies by product. The premise is that they are matched to the same standard as the mating part.

Installation uses a setting tool compatible with the part, along with a hand press or press machine. If the shape of the setting tool or the pressing force does not match, it can cause deformation, insufficient fastening, poor opening and closing, or surface damage. Perform a trial installation, then check pull strength and opening/closing before moving to mass production.

Main Applications and Selection Notes

Nickel-free specifications are considered for shirt closures, baby and children’s clothing, innerwear, and accessory fasteners that are likely to touch the skin directly or at close range. Depending on the application, also select for the required holding force, number of opening-and-closing cycles, and resistance to washing and sweat.

If the fabric is thin, excessive pressing force or too long a part foot can damage the fabric easily; if it is thick, insufficient foot length may prevent proper fastening. For stretch fabrics or open weaves, confirm pull-out strength, including reinforcement with a pressing cloth or interlining.

• Select a foot length that matches the fabric thickness and the thickness after compression.
• Evaluate corrosion and discoloration according to the usage environment, such as washing, sweat, friction, and seawater.
• For products used with metal detectors, confirm needle detector compatibility, taking into account that nickel-free still means a metal accessory.

Differences from Similar Terms

Nickel-free is a material and surface-treatment specification that mainly indicates consideration for nickel. Brass and nickel silver are names of metal materials, and whether something is nickel-free cannot be judged from the material name alone. Plating refers to the surface treatment itself, while nickel-free is a condition related to its formulation and composition.

Needle detector compatibility is a specification related to suitability for a process that detects foreign matter such as broken needles. Even if a metal accessory is nickel-free, that does not mean it is needle detector compatible.

Frequently Asked Questions