<EXISTING PROBLEMS>

In disperse-dyeing of polyester/polyurethane blends, the biggest problem is inadequate reproducibility and fastness. To obtain desirable fastness level in the dyeing of polyester/polyurethane blends, it is necessary to remove disperse-dye stains from polyurethane. Because of much staining of this sort, dyes that are dischargeable by reducing agents and alkali are often used at present, being relatively easy to remove. However, these types of dyes have disadvantages as listed below, causing inadequate reproducibility and fastness.

1. Highly dependent on dyeing conditions (temperature, pH etc.)
2. Much re-bleeding of dyes by heat-setting after RC, causing deterioration of fastness despite the removal of stains.

In the disperse-dyeing of polyester/polyurethane blends, most dyes tend to stain on the polyurethane side when the temperature is lower than 100C°, and between 110 and 120C° dyes eventually shift to the polyester side. The dyeing of polyester/polyurethane blends is often carried out around 120C°, with consideration taken for the physical characteristics of polyurethane (and their degradation etc.). There are problems such as inadequate dye fixation to the polyester side as well as inferior reproducibility when using high-temperature fixation types, because of much alternation in the proportion of polyester/polyurethane caused by various dyeing conditions.

<SOLUTIONS>

For the dyeing of polyester/polyurethane blends at 120C°, solutions for various existing problems can be summarised in the three points below.

1)	To inhibit polyurethane staining of disperse dyes and to effectively fix the dyes in polyester Anti-polyurethane-staining + polyester deep-dyeing Kayaresister UN addition to dyebath

2)	To use disperse dyes, taking both dye reproducibility and fastness into consideration Excellent polyester fixation around 120C° +good temperature/pH dependency and post-processing resistance Kayalon Polyester LW dyes

3)	To effectively remove stained disperse dyes in polyurethane by RC Excellent stain-removal in RC Kayasoaper URE