Two Way Separator Zipper

Definition and Overview

A two way separator zipper is a zipper with a separating bottom end that fully splits the left and right tapes at the bottom, usually combined with two sliders. Because it can be opened and closed not only from the top but also from the hem side, it is easier to accommodate movement while wearing and temperature adjustment.

“Two way opening” refers to the function of opening from the bottom. Since the entire zipper can be separated into left and right sides, it is a type of open zipper, and it should be distinguished from a double slider, which only means that it has two sliders.

Structure and Components

The main components are the teeth that engage to open and close, the two sliders that move the teeth, the tape, the top stop that prevents the slider from coming off at the top, and the separating bottom end that attaches and detaches the left and right sides at the bottom. The separating bottom end generally consists of an insertion pin and a retainer box, and the zipper is closed by inserting the pin and moving the slider.

The bottom stop used on a closed-end zipper is generally not used at the bottom of a two way separator zipper. When the lower slider is moved upward, an opening is created at the bottom, allowing a range of motion when sitting or walking.

• Teeth: elements that interlock left and right to form the opening and closing section.
• Slider: a part that engages or separates the teeth.
• Top stop: a part that prevents the slider from coming off the top end.
• Separating bottom end: the bottom component that attaches and detaches the left and right zipper sides.

Types and Specifications

Teeth materials and constructions include coil, molded plastic, and metal, and they are selected according to appearance, flexibility, thickness, and usage environment. Teeth size is a nominal dimension indicating the width of the teeth, and since it affects zipper strength, presence, and ease of sewing in, it is determined together with fabric thickness and application.

Length is generally specified as the length of the zipper body from the top end to the end of the separating bottom end. However, since the measurement range and display method may differ depending on the specification, when ordering, confirm not only the finished size but also whether the separating bottom end is included and the measurement standard.

• Two way specification that opens and closes from both top and bottom
• Open specification that fully separates the left and right sides
• Coil, molded plastic, and metal types based on the tooth structure
• Differences in teeth size, tape width, length, and slider shape

Main Applications

It is used for garments such as coats, blousons, and vests, where a front opening is long and mobility around the hem is needed. Because the lower side can be opened, it helps reduce pulling at the hem when seated or when wearing in vehicles, and is also useful for adjusting the silhouette.

It is also used for sportswear, outdoor wear, uniforms, and similar items, with consideration for ventilation and ease of movement during layering. Outside apparel, it may also be used for boxes and covers that require a wide opening range.

How to Choose and Points to Note

Select the teeth size and tape strength based on the thickness of the outer fabric, lining, interfacing at the front edge, seam allowance, and frequency of use. Combining a thin fabric with large, hard teeth can cause waviness, while using small teeth on a thick fabric may affect operability and durability. Check the opening and closing feel with a prototype.

In sewing, align the separating bottom end position and the left and right front edges accurately, and make sure the slider and teeth are not sewn in. For placket specifications, it is also necessary to confirm whether the thickness around the separating bottom end will make insertion difficult. If the tape is pulled tightly while sewing, waviness may appear after sewing.

For washing, close the teeth and raise the slider to reduce catching on other garments. Check in advance whether the zipper is suitable for the product’s washing method, the presence of metal parts, and processing conditions, and always perform a pretest when product washing is carried out.

Frequently Asked Questions

What is the difference between a two way separator zipper and a double slider?

A two way separator zipper refers to an open specification in which the left and right sides can be separated by the separating bottom end, and it can be opened and closed from the hem side as well. A double slider is any specification with two sliders. Even with two sliders, if the bottom end is fixed by a bottom stop rather than a separating bottom end, the left and right sides cannot be separated.

From where to where is the length of a two way separator zipper measured?

In general, it is checked as the length of the zipper body from the top end to the bottom separating end. However, whether the end of the separating bottom end or extra tape is included may differ depending on the specification and display method. Do not judge only by the pattern dimensions; confirm the dimension standard of the supplier and specify accordingly.

What causes a two way separator zipper to be hard to open from the bottom?

Causes include insufficient insertion into the separating bottom end, misalignment of the left and right front edges, thickness from fabric or interfacing around the separating bottom end, and thread caught in the teeth. It is important to perform opening and closing tests before and after sewing, and to check the position of the separating bottom end, the finish of the seam allowance, and the movement of the slider.