ECDP熔体喷丝头组件压力降研究

喷丝头组件是纺丝成形的主要部分 ,喷丝头组件压力降大小则表征了纺丝熔体的流变性和可纺性 ,同时也从侧面反映了喷丝头组件结构的合理性。本文通过对喷丝组件压力降的试验、解析 ,揭示了喷丝头组件压力降初期分布和升压的 ECDP熔体变化特点 ,为喷丝头组件结构改进和纺丝工艺的完善提供了参考依据。     

共混纺丝组件用圆盘型静态混合器及模拟实验

从共混纺丝组件内部结构设计出发,根据静态混合器的混合原理,将组件内分配板设计成圆盘型静态混合器,每个分配圆盘中都设计出若干大小相等、径向均匀分布的菱形栅。通过复合纺丝模拟器的冷态模拟实验,分析模拟熔体在分配板流道内的流动混合状态。熔体经过菱形栅之间径向沟槽多次分割和汇集后,获得位置交换,完成多次的混合操作。结果表明,用于纺丝组件的圆盘型静态混合器能满足共混纺丝要求;将静态混合分配圆盘组配置在已有的纺丝组件内,其结构设计可行,混合效果显著。     

锦纶6长丝生产中喷丝板选型的影响因素

研究了喷丝头拉伸倍数、熔体切变速率、喷丝板压力降等因素对锦纶6喷丝板选型的影响,分析了喷丝板参数之间的关系及对纺丝质量的作用,提出喷丝板选型参数的合理取值范围:喷丝头拉伸倍数在210~250倍,微孔长径比在2.5,熔体的切变速率在8 000~10 000 s~(-1),初始压力降在12~15 MPa时,有利于纺丝的顺利进行和纺丝质量的保证。     

纺丝组件结构设计及阻力计算

介绍了纺丝组件的工作原理,结构形式,纺丝组件内熔体流动的阻力计算,包括熔体通过分配板,过滤网及过滤砂的压力损失,纺丝组件的更换。指出在纺丝组件设计过程中应先选用下部快速安装组件,并根据不同品种调节过滤砂层高度。     

PA6/PE共混纺丝中圆盘静态混合器的应用研究

采用聚己内酰胺/聚乙烯(PA6/PE)熔体共混纺丝,对纺丝组件中装有不同套数的圆盘静态混合器的应用效果进行了研究。结果表明:纺丝组件中装了圆盘静态混合器,与原组件相比,其PA6,PE共混的分布均匀性及细化程度较好;静态混合圆盘的数量越多,共混物料的分布均匀性与细化程度越好;装有3套(6块)静态混合圆盘的应用效果较好,所得PA6/PE共混纤维横截面及纵向表面规整,没有孔洞,纺丝时无断头,卷绕成形良好。     

熔体直纺涤纶长丝装置熔体输送系统的工艺设计

以24头/位熔体直纺涤纶长丝装置为例,探讨了装置中熔体输送系统的设计技术要点和设计方法。结果表明:熔体输送系统的设计中,确保管道长度、管径以及熔体的流速、平均停留时间、压力降和温升等在最佳值或合理的范围,才能满足纺丝生产要求;在熔体输送配管中间增加增压泵,可使聚酯熔体进入计量泵前的熔体压力在6 MPa以上;聚酯熔体在输送过程中,除了压力降引起温升变化外,熔体通过增压泵和计量泵也会引起温升变化,可在增压泵后加装熔体冷却器将熔体温度控制在280~292℃。     

孪浇口的结构及其对聚合物熔体流变性能的影响

介绍了一种改进的点浇口－－孪浇口的结构，讨论了聚 的熔体流经该浇口时的流变性能，在浇口的长度、总截面积以及流量一致的条件下，与常用点浇口相比，弯浇口使熔体温度升高和使熔体粘度降低的程度要大，但压力降增加的幅度也大，并以聚丙烯（PP）为原料，对比分析了PP熔体流经常用点浇口和孪浇口时的剪切速率、压力降、温度和粘度的变化。当PP熔体温度为240℃时，熔体流经孪浇口和点浇口后，温度的增加值分别为25.1℃和11.3℃。与常用点浇口相比，孪浇口处熔体的剪切速率提高约0.41倍，粘度下降约0.3倍，但压力降却增加了2.23倍。     

熔体直纺288 dtex/288 f全消光扁平PET POY的生产工艺研究

将干燥的全消光母粒熔融挤出后与聚对苯二甲酸乙二醇酯(PET)熔体动态共混,采用熔体直纺工艺路线纺制288 dtex/288 f全消光扁平PET预取向丝(POY),研究了全消光母粒干燥工艺条件、螺杆温度、纺丝组件压力、纺丝温度、冷却条件、上油工艺和卷绕速度对纤维性能的影响。结果表明：较佳的生产工艺条件为在全消光母粒干燥温度140℃、干燥时间10 h,螺杆各区采用低温逐渐递增的排列形式,组件初始压力17.0 MPa,管道输送温度287.0℃,纺丝箱体温度292.5℃,冷却风压为35 Pa,无风区高度55 mm,集束位置900 mm,纤维上油率0.57%,卷绕速度2 530 m/min;在此工艺条件下,生产的288 dtex/288 f全消光扁平PET POY断裂强度为2.15 cN/dtex、断裂伸长率为130.5%、扁平度为3.2。     

熔体直纺PET-FDY工艺影响因素的研究

探讨了熔体黏度、端羧基值、熔体输送温度、压力降、停留时间、纺丝温度、吹风冷却及拉伸工艺对熔体直纺PET-FDY生产工艺的影响。     

纺丝组件内流体分配的研究

建立了组件计算模型,通过数值模拟的方法,对特定纺丝组件流道内熔体的流动进行了计算,得到了组件内熔体的流动矢量图与云图,计算出喷丝孔的质量流量分布,结果证明喷丝板外圈喷丝孔流量高于内圈。为验证结果的可靠性,通过试验测定了真实的流量数据,试验结果与模拟结果的误差在20%左右。     

Effect of the age of a spin pack on the dyeing properties of poly(ethylene terephthalate) fibres

The spin pack is an essential component of melt spinning processes. However, the age of the spin pack can affect the physical properties of polymers. The dyeing properties of poly(ethylene terephthalate) fibres over time in relation to spin pack age were investigated in the present study. With an increase in the age of the spin pack, an increase in colour strength and a decrease in fibre crystallinity were observed. The crystallinity decrease of the fibres through spin pack age was explained by the increase in polymer melt temperature due to increase in spin pack pressure.     

110 dtex／144 f涤纶细旦丝的工艺探讨

讨论了聚酯熔体中杂质颗粒、熔体温度、纺丝组件、侧吹风速度、上油方式、拉伸倍数与热辊温度等因素对涤纶细旦丝的影响。结果表明:降低聚酯熔体中的杂质颗粒直径,选择熔体温度280-282℃,纺丝温度290-292℃,侧吹风速度约4．5 m／s,纺丝组件压力13．0-14．0 MPa,采用油嘴上油,拉伸倍数2．3-2．5, 拉伸温度90-94℃,定型温度128-130℃,可生产出性能优良的110 dtex／144 f涤纶FDY细旦丝。     

LAMINAR FLOW HEAT TRANSFER WITH INLINE MIXERS INSERTS

Heat transfer coefficients were measured for heat transfer to a Newtonian fluid flowing in laminar flow through a tube with inline mixer inserts. Kenics “Static” mixer and Ross LPD mixer inserts were studied as heat transfer augmentation devices. The mixer inserts were in the inner tube of a concentric tube heat exchanger. Steam was condensed in the annulus of the exchanger. Significant heat transfer enhancement was obtained with both inserts at the expense of even greater pressure drop increases. The use of the Ross mixer insert gave greater augmentation than did the use of the kenics insert. An analysis using the analogy between momentum and heat transfer allowed the prediction of heat transfer coefficients from pressure drop measurements. The predicted coefficients were in good agreement with experimentally measured heat transfer coefficients for laminar flow.     

LAMINAR FLOW HEAT TRANSFER WITH INLINE MIXERS INSERTS

Heat transfer coefficients were measured for heat transfer to a Newtonian fluid flowing in laminar flow through a tube with inline mixer inserts. Kenics “Static” mixer and Ross LPD mixer inserts were studied as heat transfer augmentation devices. The mixer inserts were in the inner tube of a concentric tube heat exchanger. Steam was condensed in the annulus of the exchanger. Significant heat transfer enhancement was obtained with both inserts at the expense of even greater pressure drop increases. The use of the Ross mixer insert gave greater augmentation than did the use of the kenics insert. An analysis using the analogy between momentum and heat transfer allowed the prediction of heat transfer coefficients from pressure drop measurements. The predicted coefficients were in good agreement with experimentally measured heat transfer coefficients for laminar flow.     

Design and operation of screen packs

A method is presented for calculating the pressure drop in a polymer melt flowing through single or packed screens from orifice-rheometer data, screen dimensions and flow rate. A design plot encompassing standard square-woven and twilled-dutch screens greatly simplifies the calculation. The design relationships are based on the assumption that, for the narrow range of shear usually encountered in a screen pack, the flow behavior is adequately represented by the power law. These relationships were developed from theoretical arguments and wide-ranging experimental evidence reported elsewhere (1). Several examples involving screen packs in extrusion service are worked out in detail, The quantitative implications of the screen-pack equations for extruder scale-up are discussed.     

涤纶短纤维纺丝组件的使用与异常丝控制

简述了纺丝组件的结构、作用,探讨了纺丝异常丝的形成,指出熔体杂质含量高、黏度大、纺丝温度低时组件的升压速度快,注头丝、浆块类异常丝与组件相关,其控制要从组件更换、喷丝板面硅修整、组件拆装、清洗规范操作、喷丝板镜检及部位管理着手。     

368 dtex/576f多孔细旦预取向丝的工艺研发

通过120 mm大板径喷丝板生产368 dtex/576 f多孔细旦涤纶预取向丝(POY),研究了纺丝工艺条件对POY生产稳定性及物性指标的影响。结果表明:熔体输送温度为280℃,纺丝温度为286℃,纺丝组件初始压力为18.2 MPa,环吹风压为50 Pa,双油嘴上油,集束位置750 mm,纺丝速度为2 650 m/min时,可制得生产稳定和性能优良的多孔细旦POY,产品的断裂强度CV值为2.56%,断裂伸长率为122.3%,断裂伸长率CV值为2.58%,条干不匀率为0.78%。     

影响尼龙66POY线密度不匀率因素的探讨

对影响尼龙 66条干不匀的试验表明 ,适当地增加螺杆机头压力 ,一般控制在 10～ 12 MPa;更换齿轮磨损严重的计量泵 ;改善计量泵和组件的保温 ;适当增加组件压力等 ,可降低线密度不匀率 ,从而提高产品质量     

微细旦PET超短纤维的生产工艺探讨

采用半消光PET切片熔融纺丝生产PET超短纤维,探讨了纺丝工艺和油剂对生产及纤维性能的影响.结果表明:控制PET切片的含水率小于30μg/g,组件初始压力8.5-10.0MPa,纺丝温度288-292℃,喷丝板单孔吐出量0.35-0.45g/min.纺丝速度1300-1500m/min,采用国产油剂TDS-2000A及...