高品质仿毛涤纶长丝的生产工艺探讨111112

因异形高品质仿毛涤纶长丝具有高异形度、常压低温可染性的特征,其加工效率和风格受到限制,存在预取向丝(POY)加工不稳定、异形度低,拉伸变形丝(DTY)毛丝多、效率低等问题。主要讨论了从熔体到POY再到DTY制备过程的生产工艺,通过纺丝条件的择优、喷丝板的设计、加弹条件的优化等,既保证了其高异形度和品质,又改善了生产效率,纤维异形化显著,染色均匀率得到有效改善。     

高品质仿毛涤纶长丝的生产工艺探讨

因异形高品质仿毛涤纶长丝具有高异形度、常压低温可染性的特征,其加工效率和风格受到限制,存在预取向丝(POY)加工不稳定、异形度低,拉伸变形丝(DTY)毛丝多、效率低等问题.主要讨论了从熔体到POY再到DTY制备过程的生产工艺,通过纺丝条件的择优、喷丝板的设计、加弹条件的优化等,既保证了其高异形度和品质,又改善了生产效率...     

影响DT丝质量的因素探讨

对影响DT丝质量的因素如POY原丝质量、DT加工工艺、DT设备状况等因素进行了研究 ,找出DT丝加工工艺过程中产生降等丝的原因及预防措施     

不同电极加工的异形喷丝孔对纤维异形度的影响

采用铜电极及银电极加工的三叶形微孔喷丝板进行PET纺丝,探讨了不同电极加工的微孔伴随工艺条件的变化对纤维异形度的影响。结果表明:在相同的纺丝工艺条件下,银电极比铜电极加工出的微孔纺制的纤维异形度高。在不同工艺条件下,铜电极及银电极加工的微孔对纤维异形度的影响具有一致性,采用银电极加工微孔有利于提高异形纤维的异形度。     

抗静电异形竹节再生涤纶DTY的制备及性能研究

以167 dtex/48 f化学法再生五波浪一字型截面抗静电涤纶半预取向丝(MOY)为原料,在后加工设备假捻变形机上,利用自主研发的特殊异拉伸装置,制备111 dtex/48 f抗静电异形竹节再生涤纶假捻变形丝(DTY);探讨了抗静电异形竹节再生涤纶DTY的加工工艺条件,并对MOY和DTY的形态结构和性能进行了表征.结...     

纤维截面形状及集束状态对涤纶黑度的影响

以聚对苯二甲酸乙二醇酯(PET)纺丝级切片及市售炭黑为原料,采用原液着色法及高速纺丝-拉伸(POY-DT)工艺制备十字形、扁平形、圆形、三角形截面无染黑色涤纶DT长丝,通过对纤维不同截面形状、纤维束间不同堆砌结构及孔隙面积的分析,研究纤维截面形状及集束状态对其黑度的影响。结果表明:制备的异形涤纶DT长丝中三角形纤维黑度最大,十字形纤维黑度最小;异形截面纤维内部有效平均光程从小到大依次为十字形、扁平形、圆形、三角形,截面内部有效平均光程越长,光线碰到炭黑粒子概率越大,光线完全被吸收概率越大,纤维黑度提高;异形纤维束集束孔隙面积从小到大依次为十字形、扁平形、圆形、三角形,纤维束间孔隙面积越大,光线在纤维间光程越长,光线被炭黑及聚酯吸收的概率越大,纤维黑度提高。     

纺纱

加工异形纤维和中空纤维比加工普通合成纤维容易。异形纤维在梳毛(棉)机上梳理很少缠绕,纤维开松好,成条质量高。这种纤维经梳理后,所含短纤维的百分率较低,在精梳中精梳损耗小。而平均纤维长度较长。 异形中空纤维的纺纱,比异形截面纤维更为良好。在梳毛机上可制得整齐的纤维网,其     

异形DTY的加工

本文以三种异形POY为原料加工成DTY(拉伸假捻变形丝),探索加工的工艺,研究异形DTY的表面状态以及性质,为试制新颖异形低弹织物,开发新品种提供依据。     

涤纶差别化DTY的工艺选择

介绍在日本村田333-ⅡDTY机上加工涤纶细旦丝、异形丝、紧点丝、先捻丝及混纤丝等差别化DTY的工艺条件选择。该差别化DTY织造成仿丝、仿麻、仿毛与特殊风格织物效果较好,指出差别化DTY开发应注意和后加工,如染整开发相结合。     

阻燃异形涤纶POY工艺探讨

从功能性熔体制备、纺丝温度、冷却条件、纺丝组件、纺丝速度和上油量等方面对阻燃异形涤纶POY生产关键技术进行探讨。结果表明:纺丝温度为288~290℃,环吹风温度(20±1)℃,冷却风压16~20 Pa,POY纺速2 350 m/min左右,上油量0.5%时可以生产后加工性能良好的阻燃异形POY。     

The plasticating process in injection molding

A mathematical representation of the plasticating process in a reciprocating-screw injection-molding machine has been formulated as a design tool for simulating the effect of processing parameters on the melting performance, the melt temperature, and the pressure profile. Comparisons with experimental data on low density polyethylene (LDPE), acrylonitrile butadiene styrene (ABS), and polyvinyl chloride (PVC) under a wide variety of processing conditions are described.     

Influence of screw profile and extrusion conditions on the microstructure of polypropylene/organoclay nanocomposites

Direct melt mixing in a twin screw extruder is a simple and classical technique for preparing nanocomposites by dispersing organoclay in a thermoplastic matrix. In this paper, we focus on organoclay/polypropylene nanocomposites, using maleated polypropylene as compatibilizer. The objective of the work is to characterize the influence of screw profile and processing conditions on the microstructure of the nanocomposite (intercalation and exfoliation). Different screw profiles, more or less severe in terms of mixing elements, have been investigated. For each profile, different processing conditions (feed rate, screw speed) have been tested. Samples were collected both at die exit and all along the screw profiles and analyzed (X‐ray diffraction and rheometry). Numerical simulations have been performed to quantify the thermomechanical treatment experienced by the material inside the extruder. For all profiles and operating conditions, a mixed intercalated/exfoliated structure has been observed. Exfoliation increases linearly with the ratio of screw speed to feed rate, but is more important for the less severe profile. Except at low feed rate, intercalation and exfoliation do not change a lot along the screw profile. In many cases, the final microstructure is already obtained after the melting zone of the extruder. POLYM. ENG. SCI., 47:2100–2109, 2007. © 2007 Society of Plastics Engineers     

Influence of twin-screw extrusion conditions on the dispersion of multi-walled carbon nanotubes in a poly(lactic acid) matrix

Twin-screw extrusion using a co-rotating Berstorff ZE25 extruder was applied to disperse multi-walled carbon nanotubes (MWNT) in poly(lactic acid) (PLA). The masterbatch dilution technique was used whereas four different masterbatches were produced under variation of MWNT content, screw profile, temperature profile, and rotation speed which then were diluted to composites with 0.75 wt% MWNT under varied process conditions. The state of dispersion was investigated by light microscopy from which a dispersion index was quantified. Transmission electron microscopy was performed to observe the MWNT dispersion and network formation in the sub-micron scale.The state of MWNT dispersion within the diluted composites was predominated by the state of filler dispersion in the masterbatches. High rotation speed (500 rpm) that still ensures a certain residence time of the melt combined with a screw profile containing mainly mixing elements were found to be highly convenient to disperse and distribute the MWNT in the PLA matrix as well during masterbatch production as the dilution step. The temperature profile showed less influence, however, an increasing profile resulted in slightly better nanotube dispersions. By means of these processing conditions a percolation set was performed indicating an electrical percolation threshold below 0.5 wt% MWNT content as measured on compression molded samples.     

计算机机房用防静电聚氯乙烯型材研制

研究了计算机机房用聚氯乙烯防静电型材的生产工艺，探讨了不同炭黑品种、各种添加剂、工艺过程及加工条件对型材性能的影响。通过选择配方与加工条件，获得了综合性能良好的防静电型材。将其用于机房活动地板，导静电能力可达到国家标准A级水平。     

Recent developments in ICC color management

The ICC profile format specifies the widely used ICC color profile for transforming color data between different devices and color spaces. Ambiguities in the previous version were resolved in the v4 specification, which also introduced a perceptual reference medium to provide a well‐defined intermediate gamut as a target for gamut mapping and re‐rendering between source and destination data. Since the first publication of the v4 specification, there have been a number of important amendments, which collectively move the ICC color management architecture further away from its original static processing model to a more dynamic and flexibly programmable one. With the new colorimetric intent image state tag, it is possible to identify transforms which are suitable for images in an input‐referred image state and which need to be processed accordingly. ICC also provides an on‐line profile registry now, a permanent repository of profiles for standard printing conditions. The registry supports both manual selection and automated download of profiles. The floating‐point device encoding range amendment introduces support for floating point data, but also introduces a new and potentially more extensible form of color transform, known as multiprocessing elements. In the future these may be extended to provide a range of color processing capabilities that are not currently available. This is an important component of the smart and programmable CMM concept, in which the color matching module uses data in the profile as well as rules and other information to construct the most suitable transform for the image, workflow, and user preference. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 444–448, 2008     

Profile modification of resist patterns in optical lithography

A method is described to modify profiles of resist patterns in novolac and diazo-oxide containing systems. After patterning of the resist, two successive uniform flood exposures are given, one with deep UV (254 nm) at water-free conditions and the next with near UV (λ > 300 nm) at normal atmospheric conditions. The profile which results after development is vertical, concave or overhanging depending on flood exposure conditions and development processing. As the method includes a flood near UV exposure at atmospheric conditions the imagewise exposure energy can be reduced to approximately 35 percent of the normal value. Furthermore it gives also the possibility of using the resist as a deep UV resist. Another important implication is that standing wave effects are completely eliminated.     

Effect of processing conditions on the formation of polypropylene/organoclay nanocomposites in a twin screw extruder

Polypropylene (PP)/organoclay (Cloisite^©20A) nanocomposites are prepared via direct melt intercalation in a co‐rotating twin screw extruder. Maleic anhydride (MA)‐grafted PP (PP‐g‐MA) is used as a compatibilizer to improve the dispersion of the clay. The formulation used to prepare the nanocomposites is fixed and is equal to 80/15/5 (PP/PP‐g‐MA/Cloisite^©20A), expressed in mass fraction. The objective of the present study is to investigate the effects of processing conditions as well as screw profile upon the formation of PP nanocomposites. The parameters studied are the feed rate and the screw speed, which are varied independently, from 4.5 to 29.0 kg/h and from 100 to 300 rpm, respectively. The state of dispersion is quantified by wide angle X‐ray diffraction (WAXD), transmission electron microscopy, and rheological measurements. WAXD results show that the nanocomposites obtained in different conditions have an intercalated structure, with an increase in interlayer spacing. However, this interlayer spacing is globally unaffected by processing parameters. On the opposite, the proportion of exfoliation, estimated by rheological measurements, is depending on operating conditions (screw speed and feed rate). It increases when the feed rate decreases and the screw speed increases. Investigations on the state of dispersion along the screw profile are also presented. They show that no evolution of intercalated structure is observed along the screws and that screw geometry is only efficient in particular extrusion conditions to delaminate clay platelets. Numerical simulations of the twin screw extrusion process, using the software Ludovic^©, put in evidence that the total strain is a key factor for characterizing the level of exfoliation in the nanocomposites. POLYM. ENG. SCI. 46:314–323, 2006. © 2006 Society of Plastics Engineers     

木塑复合材料型材配方工艺研究

以经处理的不同粒径的木粉和聚氯乙烯(PVC)树脂为主要原料,用双螺杆挤出机挤出生产木塑复合材料型材。探讨了木粉干燥时间和温度、物料的塑化、型材截面对制品成型加工的影响,给出了木塑复合材料型材的加工工艺条件。所生产的木塑复合材料型材具有尺寸变化率小、加热后状态稳定、吸水率小等特点。     

General Observations of Constant Flow Rate Filter Pressing

Consolidating powder compacts to a uniform and high particle packing density is a central aspect of ceramic processing. Experiments on the formation of powder compacts from slurries of differing properties and filter pressed under different conditions are presented. The influence of (1) piston velocity, (2) the solid content of the slurry, and (3) slurry viscosity are discussed. A simplified theory of nonuniform cake growth is developed. This theory is based on the assumption that the cake profile is time independent in a reference plane moving with the cake/slurry interface. Classical theory assumes uniform cake density, while more difficult finite element methods are required for calculating nonuniform cake growth conditions. This theory simplifies nonuniform cake consolidation mechanics and allows simple spread-sheet-type calculations on cake uniformity. Cake uniformity is an important goal in processing. Piston stress-displacement behavior can be reasonably simulated from the fundamental cake properties (permeability and yield curve). The inverse, estimating the fundamental cake properties from piston stress-displacement behavior, appears to provide only rough estimates of these characteristic parameters. The Kozeny-Carman equation appears to reasonably fit the permeability behavior of these filter cakes.