双组分纤维的开发及应用

介绍部分双组分纤维的主要产品、技术特点、产品风格及商业化应用实例。     

Accurate determination of a deformation measure in the screw extrusion process

It is important to evaluate the deformation process accurately in analyzing mixing in extrusion. This paper discusses numerical methods to determine a representative deformation measure over the entire cross-section of the extruder channel accurately and efficiently. Two different numerical methods are introduced to determine a deformation measure over the entire cross-section of the extruder channel efficiently: (i) the first method based on the mapping sequence of the deformation gradient tensor; and (ii) the second method which does not require the evaluation of velocity gradient fields. These two methods are applied to the extrusion process of a single-screw extruder and are compared with respect to their numerical accuracy. It is found that trajectories of fluid particles are difficult to obtain especially near the screw flight and barrel surface, which causes numerical inaccuracies with respect to obtaining a deformation measure. In this paper an inverse mapping method is employed to overcome such a numerical problem. For computational efficiency and accuracy, the second method was found to be more powerful compared with the first one, especially when there are singular points as in an extruder channel.     

Preferential wetting phenomenon in bicomponent polymer melt flow

For two polymer melts spun in a side-by-side configuration through a capillary, interface shape and spinneret exit angle data are presented as a function of viscosity ratio, spinneret dimensions, and relative polymer-steel wettability. Nylon-nylon versus nylon-polyurethane bicomponent flow systems are compared. A surface tension phenomenon is postulated to be significant in controlling the bicomponent fiber interface shape for capillary length-to-diameter ratios of the order of unity.     

双组分环氧胶粘剂在我厂的应用

简单介绍了双组分环氧胶粘剂的特点、组成及固化反应机理 ,并且详细叙述了我厂双组分环氧胶粘剂的组分、配制工艺和灌胶工艺以及讨论了双组分环氧胶粘剂在我厂的应用情况 ,为我厂的军品及民用电器产品的灌封胶接提供了广泛的前景     

皮芯复合纤维及其成形理论

主要介绍了复合纤维及皮芯复合纤维的概况,纤维成形及皮芯复合纤维成形理论的研究及最新进展。介绍了模拟成形所采用的模型和方法。     

The fine structure of bicomponent polyester fibers

The application of alkaline hydrolysis to study the change in the fine structure of bicomponent polyester fibers as their surface is removed progressively was explored. The samples were prepared with a poly(butylene terephthalate) (PBT) sheath and a poly(ethylene terephthalate) (PET) core. The reagent used to hydrolyze the PBT was 1M NaOH in 75/25 methanol to water since it appeared to react topochemically with the fiber. The solution reacted more rapidly with PET than with PBT. Thus, when necessary to retard the weight loss of the bicomponent fibers, after a 2‐h hydrolysis with this reagent to remove PBT, it was replaced with aqueous 1M NaOH solution containing 0.1% cetrimmonium bromide. Unlike homofil PET or PBT fibers, where alkaline attack appeared to be confined to the surface and left the residue relatively smooth, the bicomponent fiber was attacked unevenly, and penetration to the PET core occurred before all the PBT at the surface was removed. Nevertheless, most of the reaction was confined initially to the PBT sheath. The tenacity and extension at break of the PBT–PET fiber passed through a maximum as hydrolysis progressed. The fall in tenacity at high weight losses is ascribed to increasing surface defects in the fiber surface. After removal of the PBT by the hydrolysis, the birefringence of the residue became progressively higher. The synergistic effect of the PBT sheath on the properties of the PET core and the possible causes of the nonuniform hydrolysis at the PBT surface are discussed. An equation is proposed that includes an interaction parameter, which can be utilized to determine which property is affected most by the hydrolysis of a bicomponent fiber. In this instance, it appears from the parameters that the order is strength > extension at break ≈ birefringence. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1163–1173, 1999     

流变剪切粘度测量不确定度的评定

建立了热塑性塑料毛细管挤出流变试验中测量剪切粘度的数学模型,根据模型分析其测量不确定度的来源,并以高密度聚乙烯为例分别计算各分量的标准不确定度,以及合成标准不确定度和扩展不确定度,最终报告出不同剪切速率下的剪切粘度的相对扩展不确定度以及扩展不确定度。     

Attenuating PP/PET bicomponent melt blown microfibers

This research investigated the attenuation of polypropylene (PP)/poly(ethylene terephthalate) (PET) bicomponent (bico) filaments during the melt blowing (MB) process. It was found that both mono‐ and bi‐component filaments attenuated from several hundred micrometers to a few micrometers in the first 5 centimeters from the die. However, fiber diameter distributions were found to be broad in these regions. The filaments were attenuated much slower but exhibited narrower diameter distributions as they moved further from the die. The diameters of bico MB filaments were between those of 100% PP and 100% PET filaments. The PET component in a bico filament controls the final fiber diameter. During melt blowing, filaments were aligned orderly with the airflow direction in a short distance near the die. Filament entanglements started at about 2.5 cm from the die and became more and more randomly oriented as the distance‐from‐the‐die (DFD) increased. The fiber diameter distribution of bico filaments was broader than that of 100% PP filaments. A higher airflow rate led to a narrower fiber size distribution for bico filaments.     

复合超细纤维的开发与发展

阐述了复合超细纤维的生产工艺、性能和应用 ,介绍了复合超细纤维的发展历程和开发现状及我国复合超细纤维的生产状况 ,并指出发展我国复合超细纤维应注意逐步完善国有技术 ,提高产品开发能力 ,形成一条龙开发     

双组分纤维用HDPE 1508S的开发

以乙烯为主要原料,1-丁烯为共聚单体,氢气为相对分子质量调节剂,己烷为溶剂,在齐格勒-纳塔型高效催化剂作用下,按一定的工艺条件进行淤浆聚合,并按特定的配方添加专用助剂,生产出双组分纤维用高密度聚乙烯1508S,满足国内市场需求。     

PET/PTT复合纤维卷缩性能的研究

通过对不同线密度的聚对苯二甲酸乙二醇酯/聚对苯二甲酸丙二醇酯(PET/PTT)复合纤维的热收缩率、卷曲收缩率、卷曲模量及卷曲稳定度的测试,研究了干热和沸水处理条件下的PET/PTT复合纤维的卷缩性能。结果表明:干热处理时,PET/PTT复合纤维的热收缩率随温度的升高而升高,随线密度的提高而减小;与干热处理比较,沸水加压处理后的纤维具有较好的热收缩率和卷曲性能。PET/PTT复合纤维线密度越低,其卷曲收缩能力越强,线密度为172 dtex时,纤维表现出较好的卷曲收缩率和卷曲稳定性。     

双组分聚酯纤维技术和产品应用进展

综述了赋予双组分聚酯纤维热熔黏、水溶性、卷曲弹性、超细纳米化、功能化等性能的皮芯复合纺丝、海岛复合纺丝、并列复合纺丝及裂片复合纺丝技术.指出双组分聚酯纤维在"用即弃"非织造布和耐久性合成革非织造布领域的应用将进一步增长,在传统和功能性纺织品领域保持一定市场份额,在技术纺织品领域中承担了重要角色,其发展空间值得期待.在光...     

A study of bicomponent coextrusion of molten polymers

An experimental study has been carried out of coextruding polystyrene with lowdensity polyethylene and polystyrene with high-density polyethylene, using both slit and circular dies. Two melt streams were separately fed to the die entrance and forced to flow side by side through a die. When using the slit die, wall normal stresses were measured with three melt pressure transducers flush-mounted on each of the rectangle's long sides, directly opposite each other. When using the capillary die, three different capillary length-to-diameter (L/D) ratios were employed: 4, 11, and 18. Wall normal stresses were measured for dies having L/D ratioes of 11 and 18 only. The measurements of wall normal stresses permitted one to determine the pressure gradient, and hence the viscous property. For each set of extrusion conditions (L/D ratio, flow rate, and component ratio), extrudate samples were collected. These were later carefully cross sectioned and photographed in order to examine the shape of the interface between the two components. At the phase interface of the polystyrene/low-density polyethylene system, it has been observed that the polystyrene, which is more viscous and yet less elastic than the low-density polyethylene, has a convex surface. However, at the phase interface of the polystyrene/high-density polyethylene system, the high-density polyethylene, which is more viscous and also more elastic than polystyrene, is seen to be convex. This then appears to indicate that the viscosity ratio of two components is primarily responsible for the final shape of the interface.     

A study on bicomponent two-layer slot cast coextrusion

Extensional flow of a bicomponent two-layer slot cast coextrusion process has been studied. A Newtonian and an upper-convected Maxwell fluid were considered to be the two layers, respectively, and the two-layer flow was assumed to be steady and isothermal. This choice was made as a simple model for a system which consists of two distinctly different fluids in terms of their extensional behaviors. Present study considered only the draw-down region where the film thickness changes slowly with the distance from the die exit. For this region, asymptotic solutions could be obtained for two limiting cases in which the elasticity effect of the Maxwell fluid layer is small and the applied tension at the take-off is large, respectively. When the elasticity effect is small, the melt thickness and the velocity profiles are exponential as in the case of a Newtonian single-layer flow. When the applied tension is large, on the other hand, the velocity profile is shown to be near linear. Furthermore, the viscoelasticity effect of the Maxwell fluid layer becomes so dominant that it dictates the mechanics of the coextrusion flow even when its flow rate and shear viscosity may be much smaller than those of the Newtonian layer.     

双组分皮芯型PET蓄光长丝的制备

以绿色环保的稀土铝酸盐作为蓄光剂,以PET为基体制备蓄光母粒,然后用复合纺丝法制备以蓄光母粒为芯,PET为皮的具有蓄光纤维功能的复合纤维。利用DSC、SEM研究了蓄光母粒的热性质和蓄光剂在基体中的分布,考察了蓄光纤维的力学性能。DSC分析结果说明加入质量分数为10%的蓄光剂的熔融温度与纯PET基本相同,但结晶度温度提高了38℃,结晶度增加了7.25%。SEM分析表明,蓄光粉体与PET组成的共混体系相容性很好;蓄光纤维的断裂强度达2.9 cN/dt-ex,可以满足服用要求。