Page 30 - HKK Product Catalogue 2025

CONSULTATION & RECOMMENDATION

F. Color staining on white fabric
- If acidic or oxidizing substances remain in the fabric after dyeing or finishing, they can cause chemical
reactions with metal zippers, leading to stains where the zipper touches the fabric. This is especially
noticeable on white or light-colored materials. Zippers can also react with certain dyes.
√ What you can do:
• Make sure fabrics are completely washed and dried after processing.
• Put a piece of paper between the zipper and the fabric when packaging the garment.

- Metal zipper teeth are coated with paraffin to help them zip smoothly. When these zippers are attached
to fabrics that are water-repellent or waterproof, the paraffin might melt during pressing and leave stains
on the fabric.
√ What you can do:
• When ironing, place a few sheets of paper or fabric between the zipper and the garment to
prevent staining.

- Reactive dyes used on cotton can contain metal ions. In humid conditions, these dyes can react with
the copper alloy in metal zippers, causing the fabric to fade or change color.
√ What you can do:
• If the fabric has been over-dyed, dry it completely and store it in a dry place.
• Avoid storing garments in plastic or vinyl bags.
• Keep clothes in cool, dry places - especially when storing or displaying them.
G. PU - coated zippers

- Note: This type of zipper is not completely waterproof.

- It resists water thanks to a polyurethane (PU) coating applied to the zipper tape.

- Things to keep in mind:
√ Avoid direct sunlight exposure. UV rays can cause the PU coating to yellow.
√ Always fully close the zipper when washing to prevent damage.
√ Do not iron directly over the zipper.
√ Use petroleum-based dry cleaning solvents. Chlorine-based solvents can make the zipper harder
to use, cause discoloration, or dull the PU coating.
√ Machine drying can damage the PU film and reduce the zipper's water resistance.
√ Avoid using two PU-coated zippers in contrasting colors on the same product if they’ll be in contact
for a long time (e.g. during storage or when folded), as color transfer may occur.
√ Be careful during heat-press bonding: The film softens during heat compression. If the slider
moves while the film is soft, the coating on the bonded area may peel off or be damaged.

peeling

25 HKK Zipper Catalogue for 2025