It is important to carry out relax scouring on the polyester/polyurethane blended gray fabric that has been delivered from a warehouse to a dyeing factory. Relax scouring is carried out to loosen the tension of the gray fabric structure of union stretch fabric. This way, the latent shrinkage of the stretch fabric can be reduced, and disperse dyestuff fixes evenly during the dyeing process that follows.

There are many ways to conjugate polyester and polyurethane, therefore, it is important to be aware that the relaxing method, in which the structure of yarn is loosened so that the woven or knitted structure becomes less tight, is NOT the only level that we can finally come to. Treatment technology continues to develop in Japan.

For machines to relax stretch woven or knitted fabric, a horizontal net-conveyor is believed to be nearer to the ideal than a tensionless type machine that includes a U-shaped cistern, however, there are various ways to produce stretch type yarns as seen in the figure on the right (Figure shows examples of the stretch type yarns, Toyobo's Espa). There are also various woven and knitted structures, so there are some cases in which excellent relaxing effects were achieved by using U-shaped relaxing machines.

Caustic treatment is not carried out. However, in Japan, it can be carried out with stretch materials containing Kuray's Spantel.

Espa bare yarn

Espa core yarn

Espa Covered yarn
(Single covering)

Espa covered yarn
(Double covering)

Espa ply yarn