聚合物挤出成型的新方法与新设备

本文论述一种聚合物塑化挤出成型的新方法与新设备,着重分析聚合物塑化挤出新概念和动态塑化挤出过程,并介绍塑料电磁动态塑化挤出设备的原理、结构、性能及特点。     

PVC物料挤出塑化的浅议

本文围绕PVC物料挤出塑化质量中的内在质量，从挤出机结构与发展、PVC物料在挤出机中挤出塑化的历程与机理、配方与工艺等三方面对PVC物料挤出塑化进行了较详细的讨论，阐述了提高塑化质量的相应措施。     

基于电磁动态塑化挤出的模头挤出特性的研究

本文以塑料电磁动态塑化挤出机上的圆截面模头为对象,研究了将振动力场引入聚合物塑化挤出全过程条件下圆截面模头的挤出特性,建立了圆截面模头脉动挤出特性的数学模型,并进行了实验研究,理论分析与实验结果趋向一致,从而揭示了振动力场引入聚合物塑化挤出全过程对圆截面模头挤出特性的影响规律。     

振动力场下聚合物塑化挤出技术研究

介绍玫种将电磁场引起的机械振动力场引入聚合物塑化挤出全过程的塑料电磁动态塑化挤出设备,讨论了它的原理、结构及应用,实验与生产表明,塑料电磁动态塑化挤出设备在加工聚烯烃时能耗降低２０％～５０％,挤出熔体温度降低２０℃以上,制品拉伸强度提高１６％以上,对无机填料充体系的兴旺聚散效果提高。     

一种手机壳加工用挤注复合注塑机

<正>本实用新型公开了一种手机壳加工用挤注复合注塑机,包括喷嘴、注塑料筒、挤出塑化装置和注射油缸,喷嘴的进口端与注塑料筒的出口端连接,注射油缸的出口端与注塑料筒的进口端连接,注射油缸底座底端设置有若干减震装置;挤出塑化装置通过支架设置在注射油缸的上端,挤出塑化装置由挤出流道、外筒、     

塑料电磁动态塑化挤出机的挤出功率研究与模拟

本文采用自行修正的Tanner本构方程研究了塑料电磁动态塑化挤出机中熔体输送挤出功率对振动力场的响应。建立了振动力场作用下熔体输送挤出功率的理论模型,以此为基础模拟塑料电磁动态塑化挤出机的挤出功率,并进行了实验研究,结果表明理论模拟能够在一定范围内反映实际情况,为塑料电磁动态塑化挤出设备的设计和生产应用提供重要的理论指导依据。     

螺杆轴向移动对塑化流场均匀性影响的三维仿真研究

采用Polyflow软件对相同工艺条件下螺杆挤出机和往复式螺杆注塑机塑化时计量段流道内熔体进行了三维非等温流动模拟。比较两者中温度场、黏度场、速度场及压力场分布。结果表明,挤出螺杆塑化时的温度和黏度分布更加均匀;注射螺杆后退有利于提高熔体输送能力,但挤出螺杆塑化更稳定。     

塑料异型材挤出的剪切塑化探讨

塑化问题是异型材挤出的首要问题，也是每一个挤出操作者和工程技术人员必须深入了解和把握的基本问题。目前塑料异型材生产多用锥形双螺杆挤出机，本文就针对该种机型从实用角度探讨异型材挤出中物料的塑化。     

PVC木塑复合材料生产中成型机的工艺控制

讨论了挤出机的机筒与螺杆装配精度、挤出工艺与PVC木塑复合材料塑化质量的关系,提出了调整、改善塑化质量的方法。     

几种新型冷喂料挤出机的特点及应用

本文通过对塑化段结构特点分析及实践数据的显示,对几种新型冷喂料挤出机的性能特点(挤出产量G、挤出温度T及混炼质量Q等)及应用作了阐述和对比,从而有助于人们正确选用挤出机和确定选用哪种型式的塑化段或由哪些不同塑化段组合设计出符合要求的冷暖料挤出机。     

Polyflow逆向挤出功能在异型材口模设计中的应用

比较了Polyflow用于挤出口模数值模拟的两种方法,即逆向挤出与给定口模的数值模拟,并介绍了Polyflow逆向挤出功能的基本过程;然后以一个典型十字型异型材的挤出口模设计为例,详细介绍了如何用Polyflow软件的逆向挤出功能对口模形状和尺寸进行数值预测。     

Measurement of some rheological properties of plastic fats with an extrusion modification of the shear press

An extrusion attachment for the Lee-Kramer shear press is described. With this instrument some rheological properties of lard, margarine and shortening were measured. These included extrusion pressure and specific work of extrusion. By variation of extrusion speed and size of orifice a variety of rates of deformation could be obtained. When the rate of deformation was plotted against the specific work of extrusion, curves were obtained which were nearly straight beyond deformation rates of about 1 sec^-1. The tangent to these curves represents the apparent viscosity. By measurement of the hardness before and after extrusion the work softening resulting from the extrusion could be measured. Some possible uses of the technique are discussed.     

Die design for rigid PVC—the effect of die land length on extrudate swell

PVC profile extrusion compounds have a unique morphology. While other polymers gradually decrease in extrusion die swell with increasing length/thickness (L/D) ratio, PVC profile extrusion compounds have a low die swell, quite independent of the die's L/D ratio in the range of 5 to 20. The fact that the die land length can be changed without changing the extrudate swell is an important consideration, which makes die design and balancing dies simpler and easier for PVC profile extrusion compounds. While other polymers substantially increase extrudate swell with increased shear rate, the swell of the PVC profile compounds is not much affected by shear or extrusion rate. This unique behavior allows wider processing latitude in profile extrusion and faster extrusion rates than with other polymers. Another unique factor in the rheology of PVC profile extrusion compounds is that extrusion die swell increases with increasing melt temperature, while other polymers have decreasing die swell with increasing melt temperature. The unusual rheology of PVC profile extrusion compounds is attributed to its unique melt morphology, where the melt flow units are 1 um bundles and molecules that have low surface to surface interaction and entanglement at low processing temperatures but increased melting and increased entanglement at higher processing temperatures. Other polymers, unlike PVC, have melt flow at the molecular level.     

Extrusion of polypropylene. Part II: Process analysis of the metering zone

This is a study of the extrusion of thermoplastics with special focus on the extrusion of polypropylene. A multidimensional numerical model is presented for computational simulations of the extrusion in the metering zone. The model contains a non-isothermal analysis of the extrusion of non-Newtonian melts in single-screw extruders. The computer code developed is tested against an analytical solution and against literature data for the case of a high density polyethylene. Computer simulations are carried out for the extrusion of two grades of polypropylene at two different screw rotation speeds. Special attention is paid to the evaluation of variables of practical interest, such as residence times and measures of mixing quality.     

电磁动态塑化挤出机性能的研究

本文结合理论分析，着重从实验方面分析研究电磁动态塑化挤出机的挤出特性和混合特性，证明了这种新型挤出机具有挤出产量高、挤出稳定、挤出温度低、能耗低和混合效果好等优点。     

高相对分子质量聚乙烯/石蜡油体系加工过程压力变化

采用恒速型高压毛细管流变仪测试高相对分子质量聚乙烯/石蜡油（PE/LP）共混体系的流变性能,以相对分子质量、LP含量、温度等为变量,分析共混体系在加工过程中的压力变化。结果表明,相对分子质量越大,对应临界剪切速率变小,挤出压力震荡频率和振幅增大;LP含量越少,相同剪切速率下挤出压力越大,在油含量30 ％时,出现挤出压力稳定现象,即随剪切速率的变化,挤出压力震荡现象消失;温度越高,对应的挤出压力减小,压力震荡现象减弱,震荡的频率和振幅减小。     

聚合物精密挤出过程中挤出流量的在线测量及控制方法

介绍了以PLC为控制核心的聚合物精密挤出成型过程的参数测量控制系统,针对描述挤出过程稳定性指标的参数.挤出流量的测量进行了详细描述,根据控制精度和挤出制品的不同,可以分别采用齿轮泵转速测量法、失重计量加料法、制品外径测量法3种不同在线测量及相应的控制方法,同时从测量原理、测量精度及应用范围等方面进行比较分析.     

塑料挤出成型技术研发动态

介绍了塑料挤出成型技术在振动挤出、气辅挤出、强制润滑、不停机换网、反应挤出、挤出发泡、共挤出、精密挤出近、熔点挤出等方面的研究与开发动态。     

超声波对微流道中聚合物流动性能的影响研究

为了研究超声波作用下的聚合物材料流动性能及其影响因素,利用自主开发的聚合物超声波辅助挤出测试系统,进行了超声波作用下聚合物熔体在微流道管壁的剪切力、剪切速率和表观黏度的测试,并在与传统稳态挤出相比较基础上,分析了超声波对微流道中聚合物熔体流动性能的影响。实验结果表明,引入超声振动后,微流道的入口压力降有明显降低,并且随着熔体剪切速率的增加而增大;超声振动作用下聚合物熔体剪切速率存在临界值,当剪切速率小于临界值时,超声下聚合物黏度小于传统稳态挤出聚合物黏度,反之,超声聚合物黏度大于传统挤出聚合物黏度。     

Morphological and mechanical property studies of polymer extrudates obtained by the rotational extrusion process

The orientation of the reinforcing fibers in glass fiber filled polypropylene tubular extrudates has been controlled effectively by the superposition of the linear flow in a melt extruder with torsional flow generated by rotating the capillary portion of the extrusion die of the extruder. The so produced extrudates have mechanical properties which can be balanced along the hoop and extrusion direction by adjusting the extrusion rate and the rotational speed of the die for example, the breaking load of 75N along the hoop direction increases by ～40% when the capillary of the die was rotated at 80 rpm. At the same time the Young's modulus in the extrusion direction decreased from 1100 MPa under conventional extrusion conditions to 800 MPa.