Manufacturer · Fashion & Home Accessories
As a mattress zip sewn into the cover, a No. 5 nylon coil zip is most often used, and for large and heavy mattresses No. 8, usually with two sliders that meet in the middle. For pillowcases and decorative covers No. 3 or No. 5 is enough. A coil zip is preferred because it bends around corners, and YKK is chosen when the product has a long service life and is removed for washing many times.
Why a mattress zip is a specific choice
A mattress cover is a large, heavy and taut product. The zip runs along three or four sides, bends around the corners and is opened rarely, but when opened it is under strong tension, because the cover is tight around the filling. If the zip is weak, the coil splits at the corners or the slider is damaged when the cover is removed for washing. That is why choosing a mattress zip is more of an engineering decision than a decorative one.
Zip size according to the product
| Product | Size | Sliders |
|---|---|---|
| Bed pillowcase | No. 3 | One, non-locking |
| Decorative cushion, stool cover | No. 3 or No. 5 | One |
| Sofa seat cover | No. 5 | One or two |
| Mattress cover, mattress topper | No. 5 | Two, opposed |
| Large or deep mattress, hotel mattress | No. 8 | Two, opposed |
Zip by the metre or finished length
In furniture and home textiles, continuous zip by the metre is often used – a continuous coil chain that is cut as needed and fitted with sliders. This is convenient with many different sizes. For series-made covers of a fixed size, a finished length saves operations and gives a consistent finish. Standard nylon coil zips by the metre are available in Polkom's range; with YKK, the availability of continuous chain in a specific size and colour is confirmed on inquiry.
How to calculate the length of a mattress zip
A mattress zip usually runs along the perimeter of the top part so that the top panel can open like a lid. The practical scheme is:
- Choose how many sides the zip will open – three (a lid) or four (a fully removable panel).
- Add up the lengths of these sides along the seam, after seam allowances.
- Add a small reserve for bending at the corners, because the coil must not turn sharply right at the corner.
- Decide where the sliders will meet – usually in the middle of one of the short sides, so that opening is easy.
With zips by the metre, the sliders are fitted facing each other so that the zip opens from the middle towards both ends.
Sliders and locking
- Non-locking slider – most common on covers, because the zip stays closed and is not under constant load in the direction of travel.
- Locking slider – on products for public places, where the cover must not open accidentally.
- Slider without a pull or with a detachable pull – used when the zip must be inaccessible to children or on hotel mattresses.
- Double slider with pulls that fit into each other – allows locking with a small padlock on luggage and technical covers.
When YKK pays off
For a decorative cushion that is rarely opened, any good-quality coil zip will do. YKK makes sense for:
- mattresses and covers with a long service life that are removed for washing many times;
- hotel, hospital and institutional textiles, where replacing a cover costs more than the zip itself;
- brands that give a product warranty and do not want complaints because of the zip;
- series orders where the colour and size must be the same in every delivery.
For these reasons many mattress manufacturers work with YKK zips for the premium range and standard zips for the economy models.
Common problems and how to avoid them
- The coil splits at the corner. The zip is bent at too sharp an angle or the cover is too tight. Round the corner of the pattern and check the size of the cover against the mattress.
- The slider breaks when the cover is removed. Usually too fine a size has been chosen for the load. For mattresses, do not go below No. 5.
- The zip does not reach the corners. The length was calculated without a reserve or without seam allowances. Make a sample on a real mattress, not just on paper.
- The sliders meet in an awkward place. Think about where the cover will be opened when the mattress is on the bed, and place the meeting point of the sliders there.
Sewing in and washing
Sew in the zip with a covering tape or flap so that the coil does not rub against the sheet and is not visible from the side. At the corners do not cross the coil with the seam – let the tape bend in a soft radius. Before washing, close the zip completely: an open zip bends in the drum and can be distorted or catch other laundry. Do not iron directly on the coil.
Colour
On mattresses the zip is often white, ecru or grey, in tone with the cover or the edge binding. If the cover is in a specific shade, give a number from the YKK colour card or send a fabric sample so that the colour stays the same from order to order.
Ordering through Polkom
Polkom is a Bulgarian manufacturer of accessories for clothing and textiles and a supplier of original YKK zips for series production. See YKK nylon coil zips and send an inquiry with the cover dimensions, the size, the number of sliders and the colour. We will suggest an option and a sample; minimum quantities depend on the article.
