| As a kind of non-newton fluid,the sizing agent has a variable viscosity during the sizing process of textile yarns.It's viscosity changes along with the changing of shear rate of the sizing agent.And it brings the effect to sizing performance of the sizing textile yarns.The shear rate of sizing agent improves greatly after the significant improvement of the sizing speed in high-pressure sizing process.It has much influence on the sizing speed and sizing ratio of the textile yarns.The study on the variadness of the sizing agent shear rate in high-pressure sizing will have a terrible concernful meaning to the deeply understanding and better cotrolling of high-pressure sizing.Based on the research of theological performance of several kinds of sizing agent,the paper studies the rheological properties of the textile size in high-pressure sizing process.It focus on the study of effect to the rheological performance of size caused by the improvement of sizing speed.It also studies the relationship between rheological performance and sizing ratio,sizing speed,sizing pressure.Thus to find the regularity among them and it will be beneficial to optimize the sizing process and improve the sizing quality subsequently.The paper includes several aspects as below:1.The impact of shear rate to theological performance of size was studied.2.In order to find the impact of sizing speed to size's theological performance,the theological performance of several kinds of sizing agent were studied in high-pressure and normal-pressure sizing respectively.3.The rheological performance of several kinds of sizing agent were studied and compared to find the best suitable sizing agent for high-pressure sizing.4.The impact of concentration to theological performance of size in high-pressure sizing was studied.5.The influence of sizing pressure to size's theological performance was alse studied in this paper.After analying,some deductions were attained.It follows as below:1.The viscosity of size decreases as the shear rate increases gradually.The viscosity drops quickly when the shear rate is at a low level.With the increase of shear rate,the viscosity changes slightly when the shear rate reaches certain area.And with the increase of the size concentration,the viscosity's rangeability increasees too.According to the concentric cylinder rotation viscometry,we find that the shear ratio comes within 12～40 1/s in hige-pressure sizing.2.The viscosity of potato starch is more lower and steady than corn starch at the same concentration and shear rate.So the patato starch is much better than corn starch in high-pressure sizing,for the lower viscosity of size is more suitable for high-pressure sizing when their concentration is all the same.3.With the increase of PVA in the mixed size,the initial viscosity of the size drops consequently.And at the same conditions,the viscosity of the size of mixed patato and PVA is much lower than mixed corn and PVA.Thus the former is more suitable for high-pressure sizing.4.in the process of high-pressure sizing,with the increase of sizing speed and shear rate,size viscosity decreases sharply.When the shear ratio reaches a certain point,the size viscosity will be steady,It meets the need of high-pressure sizing for the high-concentration and low-viscosity size.It's the key difference between high-pressure sizing and nomal-pressure sizing.5.During the high-pressure sizing process,sizing pressure and the shear pressure increases together at the same time of the increase of sizing speed.It result eventually in the decrease of size viscosity.And the size viscosity decreases sharply in the shear ratio of 12～40 1/s.When the shear pressure reaches a certain point,the size viscosity will be steady,The regularity is the same as shear ratio to size viscosity.Finally,this discourse illustrates the prospects of the developing direction of this topic.
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