【Detail】
PVP has a strong binding force with hydroxyl, amino and carboxyl by the lactam structure in its molecular .Usually dyestuffs contain these functional group , so PVP has a strong affinity with general organic dyestuffs ,sometimes even more than the binding force between dyestuffs and fibers. So PVP be known as “liquid fiber” .By using the properties of PVP can increase affinity between hydrophobic fibers and dyestuffs, and improve the dyeability of fibers. Such as add appropriate quantity PVP in synthetic process can make synthetic fiber be dyed evenly, and improve tinting strength and Dye Depth .For the polypropylene fiber which is difficult in dyeing, we could add about 7.5% NVP/ styrol copolymer, then for fibers the dyeing depth of acid dyes could increase 10 times and 5 times for disperse dyes. By using PVP in technology and make it uniform distribution in the fiber ,it is useful to greatly reduce the fabric color difference after drying ,and improve the adhesive force of dyes .We can get the textile dyeing products with uniform color , light heat-resistant and not easy to fade .
Except for improve the dyeability of some fibers, PVP also could improve their hygroscopicity and sunscreen ability , and greatly increase the quantity and grade of synthetic fibers. For example, the polyamide fiber and polyester fiber are popular for their high strength, high fineness, abrasion resistance, thermal plasticity ,good luster and distinct staining ,but their hygroscopicity are poor than natural fibers. So these clothes surface often be attached a layer water vapor from the air ,it influence the comfortable .Especially the hot and humid weather in summer, the clothes of poor hygroscopicity are easily close to our skin by body sweat or high humidity air .sometimes even irritating to skin . One method to solve this problem
is to add 4%~8% PVP into polyamide before spinning ,the K value of the added PVP must be 30~70, and the residual monomer content must be less than 0.1% . Then we could get the synthetic fiber, likes polyamide fiber and polyester fiber ,with high hygroscopicity, washing resistance, thermal plasticity. As mentioned above , add PVP could improve dyeing property ,Control fiber spinning speed and get different fineness of fiber .but if the added PVP K value lower than 30 ,due to the poor complexing ability between low molecular weight PVP and polyamide ,There will be a part of PVP dissolve in water and can't get high hygroscopic fibers in water treatment process. On the other hand, if PVP molecular weight more than 70, melting system viscosity increase, it makes the spinning spinneret difficult and affects the production efficiency. The PVP molecular weight too big ,the fiber we get is too hard ,so it can’t achieve the synthetic fiber requirement of soft and comfortable. Usually we use PVP-K60 to improve Polyester fibers hygroscopicity rate, at most it could achieve 20% of the weight of the fiber itself.
Stable for the influence of PVP on synthetic fiber hygroscopicity and dyeing performance as follow:
|
|
PVP (%) |
Single residue content in PVP (%) |
dissolution rate (%) |
Yellow degree |
hydroscopicity |
Fiber production efficiency |
|
17 |
5.5 |
0.02 |
4.6 |
2.5 |
9.4 |
low |
|
30 |
5.5 |
0.02 |
2.8 |
4.8 |
8.6 |
common |
|
45 |
5.5 |
0.02 |
1.1 |
5.1 |
10.5 |
high |
|
60 |
5.5 |
0.02 |
0.5 |
8.5 |
12.3 |
high |
|
90 |
5.5 |
0.02 |
0.5 |
8.5 |
13.1 |
low |
PS：
(1)Yellow degree means when add the PVP, the yellow degree that the fiber without dye after spinning, the figure less than 10 is qualified .
(2)The reason for low production efficiency: one is PVP dissolving rate increased, the other is the wire speed is slow
(3)The dissolution rate in the stable means the PVP dissolution rate for synthetic fiber in boiling water for 30 minutes
As PVP combine different dyestuffs have different combining capacity. When doing the resist printing process for polyamide fiber and polypropylene fiber. We could use PVP as parts resist agent to get design distinctive and clear printing fabric. In the production process of printing fabric, the fabric need do washing desizing after printing ,to wash away the unfixed dyes and other auxiliaries ,and to get the Printing fabric products. In order to achieve the desizing purposes without contamination the pattern and ensure the products quality, the choice of detergent is very important. Research shows that the washing capacity from the printing and dyeing industry detergent which contain PVP and aluminum silicate acid sodium is significantly higher than the detergent without PVP. and also it could prevent the color transfer in cleaning process .
