| Warp sizing is an important weaving preparation process.In recent years,people have done a lot of research on warp sizing methods and processes in order to improve sizing quality.Sizing quality mainly includes yarn breaking strength,abrasion resistance,surface hairiness adhesion and other evaluation indicators,and these sizing properties are related to the penetration and coating effect of size on yarn.The penetration of size refers to the penetration of size into the yarn through capillarity,which makes the fibers adhere to each other,thus improving the strength of yarn,hindering the slippage between fibers,and reducing the elongation of yarn;The coating effect of the size refers to that part of the size adheres to the surface of the yarn body to form a protective film,which is close to the hairiness protruding from the surface of the yarn body,and increases the abrasion resistance of the yarn,so that the yarn will not fuzz or break due to fiber dispersion after being subjected to external forces.Therefore,to improve sizing quality,it is necessary to control the penetration and coating effect of sizing solution on yarn.At present,textile enterprises tend to use high consistency and low viscosity sizing solutions,but most of the sizing solutions are difficult to maintain the viscosity in the low viscosity range when the concentration is high.In addition,high consistency and low viscosity sizing solutions often require high temperature mixing and sizing,which requires high performance of the sizing solution and increases production energy consumption.It can be seen that it is not easy to achieve high consistency and low viscosity in sizing.Sizing with the same slurry is difficult to take into account the penetration and coating effects of the size on the yarn.In order to give consideration to the penetration and coating degree of the size,reasonably control the distribution of the size on the internal penetration and external coating of the yarn,penetration/coating successive sizing method is constructed by this topic,which divides the sizing process of the yarn into two parts: the penetration of low concentration size and the coating of high concentration size,in order to achieve the collaborative sizing of penetration and coating.The research results can optimize the sizing process,promote the improvement of sizing device of sizing machine,reasonably improve the size utilization efficiency,save energy consumption,and further improve sizing quality.The main research contents and conclusions of the subject are as follows:First,by analyzing the warp sizing mechanism,the influence of sizing with different size concentration on sizing performance is studied,and the penetration/coating successive sizing method is constructed.The sizing slot of the single yarn sizing machine is simply modified,and an experimental method to verify the penetration/coating successive sizing on the single yarn sizing machine is designed.Then through the contrast experiment between low and high concentration sizing and traditional high concentration sizing,the effectiveness of low and high concentration sizing is discussed,and then the effectiveness of sizing of different kinds of sizing is discussed.The results show that the breaking strength and wear resistance times of the two sizes with low and high concentration sizing are better than those of the traditional high concentration sizing,which indicates that the penetration/coating successive sizing method is effective,and the sizing performance can be further improved by using different size combinations reasonably.Secondly,in order to further improve the sizing quality of penetration/coating successive sizing,this paper tests and analyzes the size of low concentration sizing agent and high concentration sizing agent,selects the best size formula of penetration/coating successive sizing,and carries out the size concentration combination optimization experiment on this basis.Regression model fitting,variance analysis,central combination response surface optimization and other methods were used to analyze the interaction between low concentration slurry and high concentration slurry,and the best combination of low and high concentration slurry was selected.The results showed that gelatin(with 10% plasticizer)was used as low concentration sizing agent,and acetate starch and PVA-0588 were mixed at 6:4 as high concentration sizing agent.The best concentration combination is 5.1% for low concentration slurry and 10.5% for high concentration slurry.At this time,the response value enhancement rate and grinding rate reach the best,which are 55.84% and 47.16% respectively.Finally,the permeation/coating successive sizing method is extended to warp beam sizing,and the sizing force parameters are preliminarily optimized.Through the modification of sizing tank device of XSY617-700 sizing machine,the sizing machine can realize two kinds of low and high concentration sizing in the same field,and verify the effectiveness of penetration/coating successive sizing to improve the sizing performance of sheet yarn.According to the test results,the sizing rate of low and high concentration sizing is lower than that of traditional high concentration sizing,but the performance difference of other sizing yarns is less than 3%.In order to find out the influence of sizing with two kinds of sizing solutions on sizing performance more reasonably,it is characterized by sizing reinforcement,elongation reduction,hairiness reduction,and abrasion increase per unit sizing ratio.The results show that the yarn with low and high concentration sizing of the two sizes has the best change rate of each performance ratio,in which the specific abrasion rate of sizing is 24.29% higher than that of traditional high concentration sizing,the specific hairiness reduction rate is 14.72% higher,the specific reinforcement rate is 16.35% higher,and the specific elongation reduction rate is 7.89%higher.The sizing yarn with pre pressure of 1.2 MPa in the range of 0.6-1.4 MPa has the best performance.It shows that the penetration/coating successive sizing method can effectively improve sizing quality,save sizing cost and meet weaving requirements. |
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