To improve fastness of spandex blended fibers,

(1) preventing spandex from staining during dyeing
(2) avoiding redeposition of dyes during washing

are important.

Kotani Chemical Industry recommends following recipes to improve fastness of polyester/spandex blends and nylon/spandex blends, for which we are reputed from both domestic and foreign dyeing firms.

Polyester/spandex blends recommended recipe

1. Adding “Neoleve SDX-D” (staining inhibitor) during dyeing prevents disperse dye staining(adsorption) on spandex, and helps its further distribution into polyester.
2. “Emill NW-1570” (reduction clearing agent) used in reduction clearing further washes off disperse dyes stains on spandex, leading to good reproducibility and colorfastness (including for washing, dry-cleaning and staining of test liquor).
3. When uneven dyeing occurs because of the high blended rate of spandex, adding 1~2g/L of “Newsurf MF-10” (special scouring agent) to the dye bath eliminates the trouble of uneven dyeing of polyester/spandex by emulsifying/dispersing and solubilizing silicone oil attached to spandex.

Nylon/spandex blends recommended recipe

1. Adding "Neoleve SDX-D" (staining inhibitor) during dyeing forcefully prevents acid dye staining on spandex.
2. "Emill NW-1570" (reduction clearing agent) used in soaping further washes off acid dye stains on spandex and prevents redeposition.
3. By using "Queenfix NPU-01" (fixing agent) in fixing, excellent fastness can be achieved without color alternation and dullness. Fastness can be improved significantly compared to conventional synthetic tannin type nylon fixing agents.
4. Depending on the type of leveling agent, scum may occur during treatment with "Queenfix NPU-01" (fixing agent). In this case, 0.3~0.5g/L of "Preventer S" (Anti-scum agent for nylon) can be added in the fixing bath or the type of leveling agent can be changed.
5. When uneven dyeing occurs because of the high blended rate of spandex, adding 1~2g/L of "Newsurf MF-10" (special scouring agent) to the dye bath eliminates the trouble of uneven dyeing of nylon/spandex by emulsifying/dispersing and solubilizing silicone oil attached to spandex.