熔喷法用高熔融指数聚丙烯

1熔喷工艺熔喷法是一种一步生产非织造布的工艺(由切片到纤网)。在加工过程中,高速空气将从挤压机模头端出来的熔融态热塑性树脂吹到一个成网帘带上或成网滚筒上,形成细纤维自粘合纤网。高流速的熔体从一个带有一单排小孔的模头挤出,然后通过热空气喷嘴,将熔体吹成非常细的纤维     

熔喷法非织造布生产技术的发展

介绍了几种典型的新型熔喷非织造布设备和熔喷数学模型及熔喷法非织造布原料的特点,探讨了熔喷法非织造布产品的应用。     

聚合物纺粘气流拉伸与射流性能的研究进展

叙述了纺粘法非织造布气流拉伸机理和水刺法中纤网射流性能等研究的进展;分析和评价了聚合物纺粘气流托伸的数学模型、水刺喷嘴对射流特性以及水刺纤网射流加固对水刺布质量等的影响,这也是纺粘法非织造布技术今后的研究方向。     

测速仪在熔喷和纺黏流场中的应用

介绍了热线、激光多普勒和粒子图像等3种测速仪的测量原理,装置性能和主要用途,比较了3种测速仪的优缺点。通过对比和分析得出热线测速仪适合熔喷流场的测量,激光多普勒测速仪和粒子图像测速仪适合纺黏流场的测量。     

熔喷工艺参数和喷嘴设计参数对纤维直径的影响

引　言熔喷法是 2 0世纪 5 0年代发展起来的一种制备超细纤维非织造布的方法 ,其纤维直径仅 1～10 μm.熔喷非织造布是高效精细过滤材料 ,过滤效率可达 99 9%以上 ,广泛用于医疗和环保等领域 .熔喷是依靠高速高温气流喷吹聚合物熔体使其迅速拉伸而形成超细纤维的 .数学模型对于     

熔喷法非织造布生产技术的研究展望

介绍了几种典型的新型熔喷非织造布工艺及其设备,以及熔喷法工艺的数学模型及熔喷法非织造布原料的特点等,探讨了熔喷法非织造布产品的开发及应用。     

熔喷非织造布性能的测试与分析

测试了熔喷非织造布等材料的性能,分析比较了不同试样的克重、断裂强力、断裂伸长率、透气量、透湿量等。实验发现非织造布材料的断裂强力、断裂伸长率、透气量、透湿量均与克重和厚度有一定关系,得出熔喷非织造布、纺粘非织造布和非织造布复合材料(SMS)等都各自具有独特的性能,适合开发各类功能性产品,在纺织工业上有广泛的应用。     

Optimization of air flow field of the melt blowing slot die via numerical simulation and genetic algorithm

The air flow field plays a key role in melt blowing. In this article, an optimal design procedure that improves the airflow field of melt blowing is proposed. A parameter, stagnation temperature which is a combination of static temperature and kinetic temperature, is proposed to evaluate the air flow field. The stagnation temperature is obtained via computer simulation, while optimization is accomplished by genetic algorithm. Four main geometry parameters of the slot die: slot width, nose piece width, slot angle, and setback are investigated. The optimal results were achieved in the 40th generation. The results also show that the smaller slot angle and larger slot width can result in the higher stagnation temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Simulation of the polymeric fluid flow in the feed distributor of melt blowing process

The polymeric fluid flow in the feed distributor of melt blowing process is simulated using three‐dimensional finite element method. The numerical results are experimentally verified quantitatively and qualitatively using laser Doppler velocimetry and particle image velocimetry respectively. The effects of the distributor's geometric parameters on the uniformity of the transverse flow distribution are investigated. As the manifold angle increases, the flow distribution curve appears to transform gradually from a “hill” shape to a “bone” shape. The uniformity of flow distribution at distributor outlet, especially the fluctuation at the central part, will be improved by increasing the land height. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1570–1574, 2006     

纺粘法扁平狭缝牵伸器喷射流场的数值模拟

采用标准K-ε模型描述了纺粘法扁平狭缝流道牵伸器喷射流场的湍流运动,利用有限差分法对该模型求解。通过对6种纺粘法牵伸器喷嘴的喷射流场进行数值模拟,得到了相应的流场矢量图。分析流场矢量图发现,适当减小拉伸段宽度,增加喷射喷口长度,适当选择牵伸器喷口宽度和牵伸器的拉伸段长度,有利于提高气流速度,从而有利于对聚合物熔体进行气流拉伸,使纤维直径变细,提高纺粘法成网的质量。     

Study on the flow field of the air jet from dual slot die in the melt blowing process

The possibility of describing the jet from the dual slot die in the melt blowing process with a vortex pair was studied according to the nature of the vortex. A model of the synthesis of two jets was developed. The reliability of the model was confirmed by experimental data cited from literature. The prediction of the fiber diameter using this model coincided with that using the fitted equation with the data advanced by Harpham and Shambaugh. The effects of the equipment parameters, such as the angle between the air flow and the axis of the spinneret, the width of the die head and the width of the slot were also discussed.     

Numerical analysis of the stagnation phenomenon in the coat‐hanger die of melt blowing process

In this paper the stagnation phenomenon occurred in the coat‐hanger die is investigated using a three‐dimensional finite element method to simulate the polymer fluid flow in the die. The stagnation zone is defined to evaluate the degree of the stagnation. The effects of the inlet flow rate, the slot gap, the manifold angle, and the power‐law index on the stagnation are then analyzed numerically. It is found that the manifold angle and the geometric abrupt change between the manifold and the slot have significant influence on the stagnation, and a coat‐hanger die with tear‐dropped manifolds to be capable of diminishing the stagnation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

纺黏法非织造布气流拉伸模型的研究

综述了纺黏非织造布气流拉伸机理研究的特点和研究进展。介绍了国外的研究情况,比较了这些研究方法的优缺点,分析了存在的问题。同时介绍了我国在纺黏气流拉伸方面的研究情况,分析和评价了聚合物纺黏气流拉伸的数学模型。介绍了纺黏法气流拉伸完整数学模型的基本方程组：包括连续方程,动量方程,本构方程和结晶动力方程。     

Behavior of melt electrospinning/blowing for polypropylene fiber fabrication

The fabrication process of polymer fibers has been analyzed in various ways, and several studies have been conducted to develop new processes and optimize existing ones. Several studies have been conducted on the electrospinning process, which can easily fabricate nanofibers, and the development of materials manufactured through electrospinning has also been investigated. However, research on the nanofiber fabrication and processing of thermoplastic polymers, such as polypropylene (PP), polyethylene and polyethylene terephthalate, is relatively lacking. Therefore, research on nanofiber fabrication is essential. In this study, PP fibers were successfully manufactured through a melt electrospinning/blowing process, which combined melt blowing and electrospinning. To analyze the melt electrospinning/blowing process, the dynamic behavior of the spinning process was observed using a charge-coupled device camera in real time, and the effects of the different spinning conditions were compared and analyzed. As the hot air or high voltage was increased, the spinning jet area tended to increase. In addition, the average diameter of the fabricated fibers tended to decrease as a high voltage was applied at a hot air pressure of 0.01 MPa; conversely, the average diameter tended to increase at a hot air pressure of 0.03 MPa. A similar trend was observed for the tensile stresses in the PP web fabrics. The polymer fibers produced by this melt electrospinning/blowing process can be applied as a production process for nanomembranes, filters and battery separators. © 2022 Society of Industrial Chemistry.     

Experimental study and numerical simulation the air jet flow field of a dual slot sharp blunt die in the melt blowing nonwoven process

In this work, the physical model of a polymer in a melt blowing process is established and solved by introducing the numerical computation results of the air jet flow field of the dual slot sharp inset die. The influence of the melt blowing processing parameters and the die design parameters on the fiber diameter is also studied. A lower polymer throughput rate, higher polymer melt initial temperature, higher air initial temperature, higher air initial velocity, smaller angle between slot and axis of the spinneret, smaller width of the die head, and larger width of the slot can all produce finer fibers. At the same time, the air jet flow field model of the dual slot sharp inset die of polypropylene polymer nonwovens fabrics in melt blowing process was also established. The air jet flow field model was solved by using the finite difference method. The computational simulation results of the distributions of the z‐components of air temperature and air velocity along the spinline during melt blowing process are in accordance with the experimental data. The air drawing model of melt blowing process was simulated by means of the numerical simulation results of the air jet flow field. The predicted fiber diameter agree with the experimental data. The effects of the air initial velocity and air initial temperature on the fiber diameter were studied and discussed. The results demonstrate that a higher air initial velocity and a higher air initial temperature are beneficial to the air drawing of the polymer melt and thus to reduced fiber diameter. The results show the great potential of this research for computer assisted design in melt blowing nonwoven process and technology. POLYM. ENG. SCI., 57:417–423, 2017. © 2016 Society of Plastics Engineers