BOPET薄膜生产线中铸膜系统的研究

主要讨论了BOPET(双向拉伸聚对苯二甲酸乙二醇酯)生产线中的铸膜系统，分别论述了模唇开度与静电电极位置对生产的影响，确立了模唇开度与静电电极位置的调整方法。     

双向拉伸PET薄膜生产线技术(续三) (一)双向拉伸PET薄膜生产工艺及设备

(一)双向拉伸PET薄膜生产工艺及设备2.4铸片系统铸片是将挤出系统输送来的均匀稳定的熔体通过模头流延在转动的急冷辊上,使之形成无定型的厚片,供下道工序拉伸用。铸片系统由模头、急冷辊     

双向拉伸PET薄膜生产线技术(续三) (一)双向拉伸PET薄膜生产工艺及设备

(一)双向拉伸PET薄膜生产工艺及设备2.4铸片系统铸片是将挤出系统输送来的均匀稳定的熔体通过模头流延在转动的急冷辊上,使之形成无定型的厚片,供下道工序拉伸用。铸片系统由模头、急冷辊     

双向拉伸聚酯薄膜生产线铸片工艺研究

讨论了聚酯薄膜(BOPET)生产线铸片系统的结构及组成,分别分析了模头、静电吸附系统、铸片辊对于铸片系统的影响。结合实际生产经验与理论分析,将模头的结构形式、模唇的表面光洁度和唇口开度与铸片质量整体考虑。分别探讨了几种铸片形式的优劣,给出了提高铸片辊表面精度和表面温度的方法。比较了不同的附片方式的优缺点,并介绍了在实际生产过程中附片装置的调节方法和需要确定的关键参数。初步确定了模唇精度、静电吸附系统参数及铸片辊精度等数值。     

BOPET生产中传热模型的建立与应用

针对双向拉伸聚酯薄膜(BOPET)的生产特点，建立了一套模型，用于加工过程中的传热问题研究。结果表明，对于BOPET的生产，铸膜时必须保证有充分的冷却时间，铸膜辊的直径大小取决于生产线的上限膜厚；对于特厚膜的生产，需采用双辊冷却的方法，冷却时间比最好为85：15左右；对于纵向拉伸的预热系统，采用多辊双面交替加热的方式为佳；对于横向拉伸的预热系统，膜厚对加热效果影响较小，预热区的选择取决于生产速度。     

铸铝合金硫酸阳极氧化

研究了铸铝合金的表面预处理和阳极氧化工艺;讨论了铸铝合金的表面预处理和工艺条件对阳极氧化膜耐蚀性与厚度的影响;获得了合适的表面预处理方法和阳极氧化工艺条件。     

影响BOPET薄膜厚度的因素探讨

针对影响BOPET薄膜厚度的因素进行了研究。结果表明,不同拉伸比、拉伸温度、铸片条件及APC系统的控制方式对厚度偏差影响较大。通过选择合适的工艺、控制条件可以改善薄膜的厚薄均匀性。     

双向拉伸聚酯薄膜的纵向拉伸工艺研究

分析了双向拉伸聚酯薄膜的纵向拉伸的两种组合方式——低温单点大间隙拉伸和高温两点小间隙拉伸的工艺技术特点;研究了两种拉伸组合的铸膜厚片预热、拉伸温度和拉伸倍率的相关关系以及两点拉伸的倍率分配;探讨了拉伸速率的影响因素和拉伸速率对薄膜强度和纵拉颈缩的影响。     

铸膜条件对相转化法制备PVDF微滤膜性能的影响

研究了浸没沉淀相转化法制备聚偏氟乙烯(PVDF)微滤膜过程中挥发时间、凝胶浴温度、铸膜厚度和铸膜速度对成膜的形态结构、孔隙率、过滤性能以及污染性能的影响。结果表明,随挥发时间延长,成膜孔隙率变小,纯水通量先增加后减小,以10 s为挥发时间制得的膜抗污染性能最强;随凝胶浴温度的升高,孔隙率、纯水通量及抗污染性能先增大后减小,在45℃成膜污染速率最低;随铸膜厚度的增加,纯水通量逐渐减小,孔隙率呈现先增加后减小的规律,且铸膜厚度为0.25 mm时成膜抗污染性能最好。     

含氟薄膜流延法制备方法

正1种含氟薄膜流延法制备方法 ,其中含氟树脂(FEP、PFA、ETFE)经螺杆挤出得到熔融含氟聚合物,再经流延模头挤出得到熔膜,熔膜经流延辊和冷却辊冷却定型,再经在线厚度检测,并自动反馈信息,模头进行自动调节模唇开度,得到厚度偏差控制在±2%以内的薄膜,再进行静电消除及分切收卷,最终得到的薄膜具有很好的表面平整度、光洁度和极     

Measurement and modelling of the film casting process: 2. Temperature distribution along draw direction

In the case film process a polymer melt is extruded through a slit die, stretched in air and cooled on a chill roll. During the path in air the melt cools and a reduction of both thickness and width takes place; obviously, temperature distribution, thickness and width reductions are function of draw ratio and stretching distance.Temperature distribution along the draw direction was measured as function of flow rate during film casting experiments performed with an iPP resin. A non-contacting method of measurement, based on a narrow-band IR pyrometer, was adopted.A good qualitative agreement is shown between experimental temperature data and predictions of a model accounting of radiation emissivity dependence upon film thickness. Differences are consistent with discrepancies of film thickness evolution along draw direction, indeed the model slightly over predicts both film thickness reduction and, parallel, temperature decrease along the draw direction.     

薄膜流延过程中拉伸共振现象的研究进展

介绍了熔体流延过程中的拉伸共振现象、拉伸共振形成的机理以及在牛顿流体和粘弹性流体中拉伸共振现象的研究进展 ,讨论了加工参数 (拉伸比、纵横比和空气间隙等 )和聚合物弹性对拉伸共振的影响。     

Orientation and Crystallinity Measurements in Film Casting Products

Summary Film casting experiments were carried out with iPP under processing conditions causing the crystallization process to occur under orienting flow. Draw ratio and cooling rates were changed by varying mass flow rates and die thickness. The effect of processing conditions on film crystallinity was investigated by combining WAXS and FT-IR transmission methods, while orientation of both phases was measured by IR dichroism (according to Fraser's method) and successfully compared to birefringence measurements on final films. Crystallinity appears to be almost insensitive to draw ratio and cooling rate. Moreover the crystallinity profile turned out to be also constant along the transverse film direction. Phases orientation were found relatively low and no dependence on draw ratio was detected.     

PA6/PE-LD共混物流延薄膜成型过程的理论分析与实验研究

研究了聚酰胺6/低密度聚乙烯（PA6/PE-LD）共混物流延薄膜成型工艺,从模拟和实验两方面分析了空气间隙和拉伸比对薄膜厚度和颈缩的影响。结果表明,实验和模拟有比较好的吻合性,拉伸比对薄膜厚度的影响大于空气间隙,而空气间隙对薄膜颈缩的影响大于拉伸比。     

Study of the stability of the film casting process

A theoretical study of the film casting process has been carried out. In this industrial process, a molten polymer is extruded through a flat die, then stretched in air and cooled on a chill roll. This involves mainly an extensional flow. Between the die and the chill roll, thick edges are formed and a neck-in phenomenon is observed. Above a critical take-up speed, a drawing instability, known as draw resonance, may occur. In this paper, a one-dimensional model adapted from the classical model of the fiber spinning is developed (for a Newtonian or a Maxwell fluid). The influence of the processing parameters (draw ratio, Deborah number, and aspect ratio) on geometry of the lateral free surface (the so-called neck-in phenomenon) is studied. An unattainable zone very similar to the one encountered in fiber spinning is predicted, which only slightly depends on the stretching geometry (initial film width and stretching distance). The onset of draw resonance is studied through the linear stability method. A stability zone, depending on the geometry of the process, the elasticity of the polymer, and the draw ratio, has been obtained. This instability is observed with simultaneous width and thickness film variations. It is proved that the aspect ratio (stretching distance divided by die width) has a strong influence on the onset of the draw resonance instability.     

Orientation and crystallinity in film casting of polypropylene

In the cast film process a polymer melt is extruded through a slit die, stretched in air, and cooled on a chill roll. During the path in air the melt cools while being stretched. Film casting experiments were carried out with an isotactic polypropylene resin. The temperature and width distributions were measured along the draw direction. Further, the crystallinity and Hermans orientation factor were measured on the final film. The process was described by a simple thermomechanical model derived elsewhere. The evolution of the molecular orientation parameters was calculated on the basis of a dumbbell model coupled with velocity and temperature distributions provided by the thermomechanical model. The experimental crystalline orientations of the final films collapsed into a single step‐shaped curve (from low to high orientation) if plotted versus the stress calculated by the model at the frozen line. The experimental values of the crystallinity and Hermans orientation factors are discussed on the basis of predictions of the dumbbell model for melt orientation at the frozen line and the crystallinity data obtained in quiescent conditions under the same cooling rate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1981–1992, 2002; DOI 10.1002/app.10422     

Single Solvent‐Based Film Casting Method for the Production of Porous Polymer Films

A single solvent‐based film casting process for fabricating porous polymer films is developed in this study. The porous film is produced by mixing concentrated polylactic acid (PLA)/chloroform solution (20 wt%) and fresh chloroform solvent is followed by film casting. The average pore sizes of the films produced are seen to increase from 2.1 (±0.1) µm to 6.4 (±0.2) µm with increasing ratio of concentrated PLA solution and fresh solvent from 1:2 to 1:4. Functional groups of PLA after casting into porous film are confirmed via Fourier transform infrared spectroscopy analysis. Cytocompatibility studies (via Alamar Blue assessment) utilizing MG‐63 cells on the porous PLA films reveal an increase in cell metabolic activity up to 8 d postseeding. In addition, these direct cell culture studies show that the porous membranes support cell adhesion and growth not only on the surface but also through the porous structures of the membrane, highlighting the suitability of these porous films in tissue engineering applications.     

Process model structures for transverse direction gauge control of tentered polymeric film

One of the most successful applications of multiple input multiple output control is the control of thickness in sheet forming processes including paper making and plastic film casting. While there are many similarities between film manufacture and other sheet forming processes, the physics differs from process to process. The choice of both process model and optimal control algorithm must reflect these differences. Here we consider how the basic physics of film manufacture a reflected in two classes of process models: phenomenological (interaction) models used in conventional gauge control algorithms and mechanistic models based on engineering science. Mechanistic models are more mathematically robust than purely statistical phenomenological models for some aspects of gauge control and may prove advantageous for other sheet forming applications.     

聚丙烯流延膜的加工与应用

流延法是利用热塑性材料生产塑料薄膜的方法之一。介绍了聚丙烯流延膜的性能和应用情况，讨论了聚丙烯流延过程中温度和拉伸速度等工艺因素的控制，并结合多层共挤膜中各层的作用提出了聚丙烯流延膜对原料的要求，以及加工过程中存在的主要问题。     

幅宽14m PO涂布膜机组的关键技术

介绍了聚烯烃(PO)涂布膜的性能以及在线涂覆法生产PO膜的工艺流程及工艺难点,研究了PO膜对螺杆、机头、自动膜厚控制系统、牵引张力控制以及收卷的特殊要求。结果表明:采用Φ150低剪切分离型螺杆可以很好地加工长支链茂金属树脂;采用新型中心进料机头和自动横向厚度控制系统可以提高PO膜的厚度均匀性,满足涂覆的要求;采用S型牵引装置可以解决宽幅牵引夹紧时两头紧、中间松的"哈壳"现象;采用摆动折叠方法可以解决宽幅膜较难卷绕的有关问题。试验表明,幅宽10 m以上的PO膜并非不可生产,配置合理、技术先进的PO涂布膜机组可以生产幅宽14 m的PO膜。