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The Common Defects (Fastness To Wet Rubbing) In The Process Of Flannelette Printing And The Solving

The Common Defects (Fastness To Wet Rubbing) In The Process Of Flannelette Printing And The Solving

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At present, the flannelette is classified into two class: double-face flannelette, and single-face flannelette. Cotton flannel printing can be classified into blotch printing and duplex printing. And the flannelette printing process can be classified into direct printing, resist printing and discharge printing process and so on. But the most common used in printing is reactive dye direct printing.  In order to improve the flannel quality to meet the customers' requirement, we need to know the characteristics of the flannelette and take steps and strategy to overcome the difficulties in the process of manufacturing and improve the quality of printed flannelette.
Flannelette production has a long history in our country. We usually use tabby, twill, gray fabric and let them moving on the wire roller and raising machine, forming fluffy hair on the surface of fabric, make it soft, warm and thick. After the bleaching, dyeing, printing and finishing process, the velveteen fabric has a beautiful appearance and is well received by the consumers. Flannelette is often used as winter underwear. After printing, it can also be used as an outerwear for women and children in the spring and autumn.

The common size of flannelette is as follows:
21×14 64×72、32×14 74×58、24×15 67×70、24×18 72×64 Bizhi flannelette
20×10 40×42、24×13 42×41、21×12 44×44、20×10 50×46、20×16/2 46×46 double-face flannelette;
21×6 44×42、21×4 40×40、20×6 40×34 Beibei flannelette
21×14 64×72、21×14 74×68 Jacquard flannelette
At present, the flannelette is classified into two class: double-face flannelette, and single-face flannelette. Cotton flannel printing can be classified into blotch printing and duplex printing. And the flannelette printing process can be classified into direct printing, resist printing and discharge printing process and so on. But the most common used in printing is reactive dye direct printing. In order to improve the flannel quality to meet the customers requirement, we need to know the characteristics of the flannelette and take steps and strategy to overcome the difficulties in the process of manufacturing and improve the quality of printed flannelette.

4 The fastness to wet rubbing.

4.1 The reason for low fastness to wet rubbing.
The unfixed reactive dye on the fabric is the main unqualified reasons for the fabric. The unfixed reactive dye includes: The dye that is absorbed on the fiber but not react with fiber, hydrolyzing dye and the ethylene vitriol dye with moved sulphate. The reasons that cause the unfixed dye on the fabric is as follows:

(1) the improper choose of dye
The reactive dye for printing should have the following advantages: high solubility, low substantivity, high diffusivity, high fixation rate. If the dye directness is large, the hydrolying dye and the nonreactive dye is not easy to be washed. Thus, the unfixed dye on the fabric will increase. If the dye with low diffusivity, it will not penetrate into the fabric quickly and react fully, the fabric will not be dyed fully. And the unfixed dye is large. If the dye is low in dye-fixing rate, the reaction between dye and fiber is not complete. The unfixed dye is large on the fabric, and the fastness to wet rubbing is low.

(2) high concentration dye
The upper limit of dye absorbing of fabric is called dyeing saturation value. In general, we should not give more dye than 10% of the dyeing saturation value. Because excess dye will not be absorbed by the fabric and piled up on the surface and causes unqualified fastness to wet rubbing. This principle can reasonably explain why the unqualified fastness to wet rubbing often occurs on the deeper color fabric.

(3) The quality problem of fabric
Smooth and short fiber will decrease the friction force of fastness to wet rubbing. And decrease the drop of short fiber. It is good for the transfer of unfixed dye and mechanical friction. It is good for the improvement of fastness to wet rubbing. Owing to the surface of the flannelette is rough, it will decrease the fastness to wet rubbing.

(4)the bleaching in the preliminary treatment
If the fabric is not been treated in the preliminary treatment stage, the commensal is not been treated completely, the treatment in the dyeing and finishing process will be difficulty. And the absorbing, penetrating and coloring in the process will be influenced and then the fastness to wet rubbing will be influenced. In the preliminary stage, the fabric will be mercerizing treated. In the process of scouring, considering the raising time, the waxing will cause the low capillary effect. So if  the fabric is not been treated completely at the preliminary treatment stage, the fastness to wet rubbing will not be qualified.

4.1.5 Print paste is not been treated according to the operating rules and long-time storage
How to prevent reactive dye from being hydrolyzed in the process of manufacturing and storing print paste is a problem need to note. The PH value influence the fastness of reactive dye directly. Both low and high PH value will influence the fastness of the dye. And if the print paste stores in a long time, the reactive dye will hydrolysis and influence the fastness of the reactive dye. And fastness to the wet rubbing is unqualified.

4.1.6 The incomplete even wash and bad water quality
The fabric is needed to be fully washed by water. The even wash is the important process. By even washing, the unfixed dye will be cleaned, which will improve the fastness to wet rubbing. If the even wash is uneven and insufficient, and the water is hard, the dye will combine the calcium ion and magnesium ion and form color lake, cause the unqualified fastness to wet rubbing.
What should we do to improve the fastness to wet rubbing? In actual manufacturing, we can not everything perfect. Because there are stipulated things objectively. For example,  we should choose smooth, short-fiber fabric, but the fabric has been chosen by the customers. If the customers do not decrease the requirement on the fastness of fabric, it is color body. Considering the cost, we can not buy the ideal fabric. In the process of producing print flannelette, cloth flannelette, the flannel is not short; the using dye quantity is more than needed, the fastness to wet rubbing friction is bad. The sample is deeper color can not be fully changed into light color.In the production, dye dosage is not likely to reduce; And the process like preliminary treatment and even washing after printing steaming has a great relation with the enterprise management operations, equipment conditions.Today when we talk about the wet rubbing fastness, we should see the objective existing problems at the same time, we should take effective ways and methods, do efforts subjectively.

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