Scouring of Polyester/Spandex® will remove any excess oils, waxes, lubricants, or general soil that may be left in the fiber after manufacture, handling, storage, etc. Polyester is typically a clean white when received from the factory but the whiteness of the Spandex® can be improved be a reduction bleach. Also, the overall whiteness of the blend may be enhanced by the addition of an optical brightener*. When scouring, it is important to not exceed the boil in any procedure using Spandex® as the physical properties may deteriorate. Also, do not use any type of chlorine bleach in any bleaching procedures with Spandex® as it will cause yellowing and possible degradation of the fiber.
- Enter goods into a bath at 100°F(38°C) and add:
- Circulate goods at 100°F(38°C) and raise temperature slowly to 160-170°F(71-77°C).
- Maintain this temperature for 45-60 minutes while checking the pH at 15-minute intervals. Add alkali if necessary to maintain pH of 8-9.
- At the completion of the reduction step, the bath should be cooled to 120°F(49°C) and dropped.
- Refill and run a warm rinse at 100-120°F(38-49°C) for 15 minutes. Drop this bath and refill.
- Add 1.0% owg of hydrogen peroxide 35% and raise temperature to 100-120°F(38-49°C) and run for 15 minutes. Drop bath, and extract.
It is very important to be sure that any traces of reducing chemicals are not carried over into the dyeing cycle if the goods are to be used as a ground for pastel or deeper shades.
** Recommended for fabrics which contain a high degree of grease, oil and/or graphite.