Product developers at Karl Mayer, the leading warp knitting machinery building company, have developed a semi-rigid fabric which, with the right finish, is flexible enough to be comfortable to wear and also tough enough for long-term use.

The key element of this innovative textile is a tricot fabric combined with a coating made from polyvinyl acetate (PVA).

Suppleness and dimensional stability

The conventional ways of making materials stiffer is to carry out heat-setting and/or to apply an acrylate dispersion in water – two processes that form the cornerstones of what is currently possible, the company reports.

Coating with PVA is an alternative to these processes, according to the manufacturer. The amorphous, odourless and tasteless PVA coating is said to increase the stiffness and consequently the dimensional stability of the warp knit, without having any great effect on its textile characteristics.

Both the breathability and specific handle of the knitted fabric are said to be retained. The coating also increases the light and weather resistance of the textile. Additionally, the PVA reduces flammability and is harmless to the skin, Karl Mayer reports.

Finishing of tricot fabrics

To apply the PVA dispersion, the product developers at Karl Mayer worked closely with the finishing specialists at Textilveredlung Erzgebirge, a commission finisher that is experienced in the finishing of warp knits and operates a modern machine plant.

Warp-knitted textiles produced on a TM 4 EL in a gauge of E 28 were used during the stiffening trials. The knitted fabrics were made from 100% polyester and had a subtle pattern featuring slightly structured effects. The PVA coating could therefore be applied with no problems whatsoever.

By applying the thermoplastic material, semi-rigid textiles were produced having a technical, grainy feel. The semi-transparent ground remained unaltered, so that the finished fabric also provides adequate porosity to permit air and heat exchange, thus offering a high level of comfort.

Textiles with durable inserts

The main application for these semi-rigid warp-knitted textiles is in sports shoes, according to the manufacturer.

However, the PVA-coated tricot fabric is also suitable for other applications where dimensional stability, textile suppleness and weather resistance are all needed. Examples of possible products include covers for garden furniture, sunscreens and bag/luggage materials.

www.karlmayer.com