For best results, fabrics woven of 100% acetate should be dyed in an open jig or atmospheric beam dye machine to help minimize the formation of creases and crack marks. Fabric blends made with acetate warp yarn and spun rayon filling can be dyed in open becks and atmospheric-jet dye machines. When dyeing blends, care should be taken not to overload the becks or jets and to maintain a bath ratio of 20:1 to 30:1. Overloading can result in severe crack marks that cannot be removed on the tenter frame during drying.
Scouring and Desizing
Anionic detergents are preferred to nonionic detergents in scouring because it
is more difficult to remove nonionic detergents from fabric. Residual nonionic
detergent left on the fabric will interfere with the dye dispersion. This is especially
important in jig dyeing where the efficiency of rinsing is not good. Avoid using
caustic, strong alkalis or cationic detergents since these may impair removal
of the size. Also, if acetate is exposed to pH levels greater than 9.0, significant
delustering and saponification will occur, converting the acetate to regenerated
cellulose. This will adversely affect the dyeing process. A simple test to see
whether saponification has occurred is to expose the desized but undyed fabric
to direct dyes.
- Before dyeing, thoroughly remove any warp size to avoid
warp streaks in the finished fabric.
- Rinse in cold water to remove any tints that might be present.
- Set bath temperature at 38°C (100°F).
Add anionic detergent and soda ash to pH 8.5-9.0.
- Raise temperature to 71°C-82°C (160°C-180°F). Hold 30 to 60 minutes.
- Cool to 60°C (140°F). Overflow rinse 10 minutes, then drain.
- Repeat rinse at 49°C (120°F).
- Drain and refill for dyeing.
Cellulose acetate should always be dyed with disperse dyes. In jig dyeing, lower
energy dyes are preferred over higher energy dyes. Basic dyes (also known as cationic
dyes) may yield brighter shades, but may also dye unevenly. Basic dyes have no
affinity for acetate, and any dye that only stains a fiber will tend to go on
non-uniformly. In addition, basic dyes have a good affinity for acrylic, which
is present in many of the sizes used on acetate. If the size is not completely
removed, the basic dye will tend to dye the acrylic size and cause warp streaks.
Fabrics containing 100% acetate and blends of acetate with spun rayon can be dyed
- Add the following auxiliaries to a fresh bath at 27°C (80°F):
0.33 g/l sequestrant, or Calgon water softener
0.08 g/l monosodium phosphate
0.07 g/l anionic detergent
Note: Additional auxiliaries will be needed depending on the type of dye
used for the rayon
- Adjust pH to 6.5-7.0.
- Add disperse dyes that have been pasted in warm water with a small amount
of anionic detergent and dispersed in water at 71°C (160°F).
Note: Rayon dyes should be added and mixed according to the manufacturer's
- Raise temperature slowly to 82°-88°C (180°-190°F).
- Dye for 1 hour at 82°-88°C (180°-190°F).
- Dyeing at temperatures above 93°C (200°F) may result in delustering and/or
- Drop bath.
- Rinse well.
Drying of Dyed Fabric
In many instances, excess moisture is removed from dyed fabrics by running open width fabrics over a water extraction suction slot. This makes drying of fabrics more economical. Acetate fabrics are generally easy to dry due to their low moisture regain. Lining fabrics are generally dried by passing over metal cylinders that are steam heated to 250°F-300°F. Some fabric constructions can be dried in loop dryers or tenter frames at 200°F-275°F. With either method, tension in the length and width directions must be kept to a minimum to not distort the fabric. Excessive drying temperatures will reduce the naturally soft hand of acetate fabrics.
Disperse Dyes for Use With Selected Acetate
Disperse should be selected based on the colourfastness properties required. The
following is a list of some disperse dyes that have been used successfully on
acetate for many years:
Disperse Yellow 3
Disperse Yellow 34
Disperse Yellow 86
Disperse Orange 5
Disperse Orange 25
Disperse Orange 58
Disperse Orange 59
Disperse Red 78
Disperse Red 117
Disperse Red 135
Disperse Blue 3
Disperse Blue 7
Disperse Blue 27
Disperse Blue 102
Disperse Black 3