How to make waterproof piping trim?

Piping cord is usually used for clothes and bags. For clothes, we need soft braided piping trim. For bags, leather or TPU piping cord is supposed. Nowadays, some bag manufacturers and designers would like to use waterproof piping welt. Not only because of its water resistance but also for the abrasive resistance performance. To get a piece of waterproof piping cord, there are two main ways. One is covering waterproof material on braided piping trim while another ways is choosing waterproof material to make piping cord directly.

As a manufacturer of TPU piping welt, we use the second way to make waterproof piping cord. The main manufacturing method is extrusion. On the basis of extrusion technology, TPU piping cord manufacturing should have several steps. The first step is to confirm the type. Pure TPU piping welt and TPU coated piping tape request different material. Pure TPU piping welt request TPU raw material only. But TPU coated piping cord asks for braided polyester cord besides TPU material. Secondly, the size of piping cord should be confirmed, including the diameter of the round cord part as well as the width and thickness of the flat part. With the data and information confirmed, we can next find out or make a suitable mould to prepare producing.

If producing pure TPU piping cord, we can start running extrusion machine at this step. However, when producing TPU coated piping trim, we should purchase and neaten the inner braided polyester rope cord before. Of course, the diameter, shrink range and color of polyester cord should be focused and confirmed. Then through extrusion machine, polyester cord will be inset into the round cord part of TPU piping cord while the flat part will be pure TPU. One point is that the inner braided cord can’t be pulled out.

Some customers ask for pure TPU piping cord with tube in the round part. That’s not hard. The key point is mould. Within the tube, braided cord or wire can be putted in. But if the inner cord weren’t be needed to pulled out, we would recommend TPU coated piping welt.