Pre-wet Sizing Mechanism And Its Applications

Pre-wetting sizing is a new sizing process. In this process, warp should be immersed into water and be cleaned firstly. So warp is wet before it enters into size box. It's advantages, improving sizing quality and saving size, has been accepted by enterprises and scholars. However there are many problems and different standpoints about pre-sizing. In this thesis, we do some studies on mechanism and application about pre-sizing.Interface mechanism is studied firstly according to knowledge of interface physical chemistry. The following conclusions have been made. Firstly, wetting property of yarn can be improved. Secondly, size can be well distributed within the yarn. And attachment between size and yarn can be improved by pre-wetting sizing.Then the permeation mechanism is discussed. Yarn is abstracted to porous medium firstly. And fiber distribution is studied, using concept of interspaces distribution and porosity. After that, theory model of liquid size permeating in the warp is obtained. According to permeability, factors affecting permeation property of size is analyzed.When studying process of pre-sizing, we firstly do sizing experiment in the laboratory. The reasonable ranges of pre-wetting moisture regain and pre-wetting pressure are confirmed. On the pre-wetting sizing machine, process of pre-wetting sizing is studied system. And the sizing quality between traditional sizing and pre-wetting sizing is contrasted and analyzed. By observing sizing yarn chip, we see that evenness of sizing distribution is improved greatly and size in yarn is increasing gradually from inner layer to outside. After observation with microscope, we see that yarn of pre-wetting sizing looks smooth outside and hairiness is kept close to the yarn body.On the basis of calculation about traditional sizing percentage, we studied that of pre-wetting sizing. We put forward to the concept of "reservation coefficient" and deduce the formula suitable to the calculation of sizing percentage of pre-wetting sizing. After calculation, we think that the sizing percentage of pre-wetting sizing is 20 to 40 percent lower than that of traditional sizing.Finally, we put forward the concept of "dry outside and wet inside". And "pre-wetting and pre-drying", which is a new thinking about sizing process, is put forward.Graduate Student: Maolei (Textile Engineering) Directed by Professor Xing Mingjie and Associate Professor Dou Yukun...