The Conditions and Key Point for Cold Dye

1. Rayon fabric cold dyeing process and receipt

Process: padding(padding pool liquid 30L, 100%pick-up rate)→pile up for 16h→hot water washing→ soaping→ drying

Dyeing recipe/(g.L-1)：

Novacron red C-2BL 0.8

Novacron yellow NP 0.6

Novacron blue C-R l.2

Penetrant 4

Dye fixing agent recipe/(g.L-1) ：

380Be water glass 200

L00% soda 30

(dye:  fixing liquid: =4:1)

2. The key point for controlling the cold dyeing of rayon fabric

(1) Adjustment of fabric tension

The wet strength of Rayon fabric is low, and it is easy to break when the warp tension is too large, so it is necessary to adjust the equipment reasonably and reduce the tension. When coiling, we should adopt the center take-up initially, and changes the weaving way of fabric, and the effect is better.

(2) Dye selection

The structure of man-made cotton fabric is different from that of pure cotton fabric, and the dyeing process is different. Therefore, it is very important to choose dyes which are suitable for cold dyeing of man-made cotton fabrics. Practice shows that using the reactive bright blue to dye cotton fabric with cold dyeing technology, the color is very shallow at low temperature. The is mainly caused by the big molecular structure reactive bright blue , surface fiber cotton fabrics are difficult to enter into the molecular structure of fiber. The activity of B-RV blue is better for dyeing effect. For the cold dyeing, because of a greater amount of caustic soda. It takes only half an hour for the liquid in padder to became starchiness, unable to use. At present, The C-reactive dyes made by Huntsman Corp for dyeing cotton cold is a good choice.

(3) Seam mark

Seam Mark has always been a problem in cold dyeing, and most of the solution is to put adhesive tape on the seam. The seam mark is mainly caused by: the uneven folding cloth at the seam mark , large amount of liquid volume, excess volumes overlap when printed on liquor. To improve the quality of the seam can solve or alleviate the seam mark, such as change of the five thread sewing clothes machine to two thread sewing machine. If the pressure on the joint of upper part and the lower part is greater, and the central active take-up can be adopted to reduce the extrusion pressure.

(4) Rolling

When the cotton fabric is wet, it expands, and the fiber diameter is nearly twice as big as that of cotton. Under the same conditions, the rate of man made cotton fabric is 55% - 60%, while that of man cotton fabric is 100% - ll0%. Increasing rolling pressure has little influence on its rolling rate. Therefore, we need to control the roll diameter and speed to ensure that the fabric color uniform.

3. Soft

The dyeing of man-made cotton fabric is better, and the dosage of softener is 1/3 of all cotton fabric. Too much softening agent has an effect on the sewing slip of the ready-made clothes.

4. Anti-shrink

The cotton fabric shrinkage in warp direction is larger. According to the general requirements of cotton fabric less than -3%, there must be enough moisture shrink, namely soft cloth falling can not be too dry and give a certain humidity shrink at the same time. If it shrinks too large once, and cause wrinkle mark, we can adopt two times anti-shrink.

Conclusion

(1)The man made cotton fabric cold dyeing is not only solved the problem of a cylinder with batch dyeing production but also avoid the crease mark and dyeing cloth cutting problem. It is substantially increasing in production capacity and stable quality.

(2) For the cold dyeing of man-made cotton fabrics, choose we should take into consideration of the fabric structure, desizing effect, dyeing and washing water when we choose the proper equipment and process. The C type reactive dyes of Huntsman Corp are choice for cold dyeing of cotton fabrics, but the cost is high and the light color can be produced.

(3) joint mark can be improved by improving the interface, tape and reducing rolling pressure and other measures..