FAQs about YKK® zippers and sliders

October 29, 2016 YKK USA

Q1. A slider sometimes catches on a piece of cloth when opened or closed. Is there any way to free the slider without causing damage to the cloth?

A1. Remove the trapped cloth by moving the slider back while pulling the cloth outward. Take care to avoid the possibility of the zipper getting caught when opening and closing it.

Q2. The slider does not open or close smoothly.

A2. The elements’ gears can be damaged by forcing a slider that does not open or close smoothly. Apply paraffin or the lubricating spray ZIPPYCOOL® to the front and back side of the elements and move the slider up and down several times to work in the lubricant and make the slider work smoothly.


Q3. Elements have been lost.

A3. Trying to forcibly close a zipper in a bag that has been overfilled will cause an excess load on the elements. This stress may cause the elements to slip out from the tape. This is a fatal problem with a zipper. The zipper should be closed only after bringing the two element’s sides near each other so that the slider can move more easily.


Q4. YKK produces zippers throughout the world, but are their quality and function of an equal standard globally?

A4. All the zippers produced and sold throughout the world by YKK meet the quality standards set by YKK, so there is no difference in quality and function. For further details, click here. However, special care should be taken regarding the existence of counterfeit zippers. Details on our brand protection activities can be found here.

Q5. A zipper made of or coated with nickel caused an allergic reaction on direct contact with skin. How can I avoid it?

A5. When a silver-colored metal zipper is required, choose an aluminum zipper. We offer a variety of products which meet European Nickel Directive (now part of REACH). Please ask your YKK representative for “N-ANTI” or “anti-nickel” products.

Q6. Do YKK products contain lead?

A6. Except for a few specialized items, the lead content levels of YKK products meet the following regulations & standards: CPSIA, EN71-3, and OEKO-TEX® Standard Class I. See “Laws & Regulations” for details.

Q7. Are YKK products treated for needle detection machines?

A7. YKK has researched and developed materials, surface treatments, strengths, and zipper designs to prevent false needle detection.

Q8. What are the points to be noted when using zippers in baby wear?

A8. Special zippers, such as zippers with plastic top and bottom stops, are offered for infants and kids wear. Please ask your YKK sales agent for more details.

Q9. What type of zipper works best with garments made of a thick material?

A9. Example: If a garment is made with a piece of material that has a weight of 12 oz. or more, you must use at least a number four size zipper or larger. If you use a number three size zipper or smaller with this type of material, the zipper elements may break.

Q10. What should you do when material gets caught in a slider?

A10. Please leave enough room for the slider to move smoothly when sewing the zipper onto the fabric. If the slider gets caught, pull back the slider slowly before moving the fabric. Do not use excessive force to move the slider to avoid damaging pull-tab or fabric.

Q11. How can manufacturers prevent a zipper tape from becoming discolored and worn by chemicals found in detergents?

A11. They should use a YG type zipper. We recommend this zipper because its chain is stronger than most zippers, which enables it to withstand the wear and tear caused by the washing process. After washing this zip, be sure to rinse it thoroughly to ensure that acids do not remain on the tape. Since chemicals can sometimes have an adverse effect even on this fastener, we recommend testing it after it is washed.

Q12. Can zipper tape become discolored in a home laundry?

A12. A zipper’s tape will not usually lose its color in a home laundry. However, discoloration may occur if the tape comes into contact with vinyl chloride, synthetic leather, or a resin coated material. When the tape comes into contact with these substances, a chemical reaction often causes it to lose its color.

Q13. How do I prevent the zipper elements from melting during ironing?

A13. Using proper heat for the material being ironed is not limited to clothing but is also applicable to zippers. Zippers can be kept durable and beautiful by considering the material of which they are made and ironing with the proper heat. A zipper should always be closed before ironing, the slider fixed in the proper position and the zipper should be covered with a piece of cloth regardless of the material of which it is made. The slider’s pull-tab should never be ironed when erect or on the reverse side. We recommend to keep the ironing temperature below 130°C (266°F) for VISLON® zippers, below 150°C (302°F) for woven in type (EF) zippers, and below 160°C (320°F) for CONCEAL® and coil zippers.


Q14. After bundling some zippers with rubber bands, the bundled part of the zippers discolored.

A14. Please avoid bundling zippers with rubber bands for prolonged storage.

Q15. I am concerned that a pin-lock type (DP) slider used on a pocket may hurt users.

A15. Please avoid using DP sliders where sharp points may cause injury. DP sliders are especially not recommended to use for Baby / Infant Products.

Q16. What kinds of zippers are recommended for baby/infant products?

A16. Products/features such as plastic stops are available for baby/infant products. Contact a YKK representatives for more details.

Q17. My zipper doesn’t pass the needle detection.

A17. YKK offers KENSIN® zippers, which meet the NC-A level for needle detection standards set by the Japanese apparel industry.

Q18. There’s a stain on my fabric that migrated from a metal zipper after being stone washed. Why do metal zippers cause staining after stone washing?

A18. Please see “Stain Migration from Metal Zippers during Stone / Sand Washing” in the Zippers Usage Instruction Manual for information on stain migration.

Q19. What type of zipper is recommended for stone/enzyme washes?

A19. For zippers which go through stone/enzyme washes, YZiP® fastening products are generally preferable compared to the standard type metal zippers. Please see“2-1 Why YZiP® products are recommended for Stone / Enzyme Washes?” in the Zippers Usage Instruction Manual p13 for information on stone/enzyme washes.

Q20.I have a problem with a metal zipper changing color.

A20. There are various types of problems with metal zipper discoloration. Please see the pages below for details:

2-2 Change in Metal Zipper Color caused by Garment Dye Treatment

2-3 Change in Metal Zipper Color caused by Bleaching

3-2 Change In Metal Zipper Color caused by Leather Products

3-3 Change In Metal Zipper Color caused by Wool Products

Q21. What kind of things do I need to watch out for when using AquaGuard® water repellent zippers?

A21. Please see “3-1 Proper Usage of AquaGuard® (Water Repellent) Zippers” in the Zippers Usage Instruction Manual for the information on AQUAGUARD® zipper usage.

Q22. What do I need to watch out for when using aluminum zippers?

A22. Please see “3-4 Cautions for Aluminum Alloy Zippers” in the Zippers Usage Instruction Manual  for the information on aluminum zippers.

Q23. I’ve tried to pair up the left side of an open-ended coil zipper with the right side of another open-ended coil zipper to use in a jacket liner, but they don’t match properly.

A23. Please see “4-4 Problem with Pairing up Different Stringers” in the Zippers Usage Instruction Manual for the information on open-ended coil zipper pairing.

Q24. How can I avoid safety issues caused by the protruding edges of coil zipper elements?

A24. Please see “4-1 Proper Sewing of Coil Zippers” on page 31 of the Zippers Usage Instruction Manual for avoiding coil zipper sharp edge problems.

Q25. What do I need to know when choosing colors from the YKK Color Card?

A25. Please see “1-3 Light Sources & Metamerism” on page 7 of the Zippers Usage Instruction Manual for information on choosing colors.

Q26. What do I need to know about washing items with zippers?

A26. A zipper should be closed and the slider fixed before cleaning. Left open, the tip of the slider may damage the fabric or the tape may become stretched or may shrink. Strong alkaline detergents or chlorine bleaching agents used to remove oil or stains dissolve paraffin or oily film and must be used with care. If a zipper does not function smoothly after cleaning, apply paraffin or the lubricating spray ZIPPYCOOL®, and work the slider up and down several times until it works smoothly.


Q27. Why does paint often come off of a slider after dry cleaning / washing?

A27. Please see “2-8 Slider Paint Chip Off” on page 21 of the Zippers Usage Instruction Manual for the information on slider paint chip-off.

Q28. I am an individual consumer, and my zipper broke! How can I find a replacement?

A28. YKK manufactures millions of zippers a day for sale to our customers who produce consumer goods like jeans, tents, luggage, sporting goods, etc. We are not set up to sell one zipper to an individual. Instead, American & Efird, the thread company, serves the home sewing market for us. Contact them on their website and someone will provide you with the retailer nearest to you who carries YKK® zippers. We appreciate your interest in YKK.

Q29. What does the product code mean?

A29. Please refer to the YKK Zipper Nomenclature guide.

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