Karl Mayer, Brückner Team Up To Develop Seamless Finishing Method

Warp knitting and technical textiles equipment supplier Karl Mayer Textilmaschinenfabrik GmbH and textile finishing machinery supplier Brückner Textile Technologies GmbH & Co. KG, both based in Germany, report they have developed a method for continuous finishing of seamless, warp-knitted fabric in open-width form.

Using Karl Mayer's RDPJ and DJ machines, seamless goods can be knitted with a built-in selvage. This selvage can then be used to hold the open-width fabric in place during heat-setting in the tenter. Karl Mayer reports the two-bar raschel RDPJ and DJ machines can produce variable-diameter tubular goods; goods with functional zones knit into specific areas and knit-in seams; and decorative effects with different patterns on the front and back of the fabric or open-work jacquard designs.

During recent trials, a Karl Mayer RDPJ 4/2 machine produced three long-sleeved shirts in a fabric panel featuring two knit-in selvages. The fabric was comprised of 81-percent nylon and 19-percent elastane.

The new processing method offers a pre-heat-setting stage directly linked to the warp-knitting process. According to the companies, this pre-heat-setting reduces tears, creases or snags in the fabric; and also reduces color and elasticity variations, and fluctuating widths.

In typical relaxing and heat-setting of seamless goods, the separate tubes or stockings are attached to a special frame prior to processsing. Brückner's Power-Frame VNB tenter features a perforated belt carrier that supports and transports the fabric vertically through the machine with a gentle vibrating effect to relax the fabric and promote shrinkage in the steamer zone. According to Karl Mayer, the VNB tenter also features: an intensive steamer with fabric relaxation on the belt before the drying section for low residual shrinkage values; a precisely adjustable dryer with uniform air and temperature distribution over the length and width of the fabric; short fabric paths to reduce stitch distortion and fabric stretching; pyrometric fabric temperature control for accurate monitoring and future reproducibility of heat-setting time and temperature; and a cooling zone at the machine's exit to instantly cool and condition the fabric.

The companies report the trials performed on the long-sleeved shirts showed minimal differences between the inner and outer fabric panels with maximum variations of +/- 1 centimeter. Maximum residual shrinkage after washing at 60°C was between 0 and 5 percent.

According to Karl Mayer, this new knitting and finishing technique offers cost savings, and is particularly well-suited to fishnet stockings, lingerie, outerwear, sportswear and medical textiles.