中原大化研发成功新型泡沫塑料

河南省中原大化集团公司三聚氰胺泡沫塑料树脂工业化生产技术和三聚氰胺泡沫塑料工业化生产技术，近日通过鉴定，此技术标志着该公司已成为国内唯一拥有三聚氰胺泡沫塑料生产技术的企业。三聚氰胺泡沫塑料是一种高开孔率的三维网格结构的新型泡沫塑料，具有优异的吸声性、阻燃性、隔热性、耐湿热性、卫生安全性和良好的二次加工性能，目前国外只有德国巴斯夫公司拥有专利并进行该产品的生产。目前中原大化集团公司对三聚氰胺泡沫塑料的中间试验基本完成，已具备工业化生产条件。     

三聚氰胺泡沫塑料在船艇机舱吸声降噪中的应用

针对噪声严重影响军用船艇战斗性,而船艇噪声主要来自机舱的实际情况,对某型军用船艇机舱进行了噪声测试及频谱分析,发现机舱噪声辐射的主要频段,计算了混响对机舱噪声的影响,制定了采用吸声材料降低机舱混响的降噪方案.通过研究驻波管实验法测试不同密度、不同厚度的三聚氰胺泡沫塑料的吸声系数,确定了三聚氰胺泡沫塑料的结构参数.按照设计方案实船安装了三聚氰胺泡沫塑料并进行噪声测试,其结果为机舱平均声压级降低了5.6 dB,达到设计要求.     

可发性改性三聚氰胺–甲醛树脂的制备工艺及配方优化

将甲醛溶液和多聚甲醛按质量比1∶1与一定量的三聚氰胺、改性剂(聚乙二醇200、己内酰胺、一缩二乙二醇、乙二醇)在一定的反应条件下制得可发性改性三聚氰胺–甲醛(MF)树脂,并在80℃下对其进行发泡制备泡沫塑料。采用正交实验考察了反应温度、p H值、甲醛/三聚氰胺物质的量之比(F/M)、改性剂种类及其用量对改性MF树脂固含量、黏度、储存期以及泡沫塑料表观密度的影响,在此基础上通过改变F/M、提高反应温度等单因素实验确定了制备可发性改性MF树脂的适宜优化工艺及配方,即反应温度90℃,p H=9,F/M=2.8,改性剂己内酰胺用量为三聚氰胺质量的14%。在优化工艺及配方下得到的改性MF树脂溶液黏度为1 547.5 m Pa·s,固含量为70.5%,储存期76 h,改性MF树脂发泡性能优良,发泡后泡沫塑料的表观密度为32.76 kg/m3。     

万吨级PE-HD燃气管专用料生产装置技术开发

对高密度聚乙烯(PE-HD)燃气管专用料的生产装置进行设计,具体阐述了双螺杆挤出机装置工艺及配置技术的设计,经过试车验证,该生产装置投产后各项指标初步符合设计要求,可实现规模化生产.     

新品开发

新型阻燃泡沫塑料在京面世前不久,北京绿寰宇化工有限公司实现了三聚氰胺泡沫塑料从实验室技术到工业化生产的过渡,这种吸声效果良好的泡沫塑料具有优异的阻燃性,能够消除传统泡沫塑料的火灾安全隐患。据介绍,一般的泡沫塑料如聚烯烃、聚苯乙烯、聚氨酯等自身易燃,燃烧时熔融并产生流滴进而引发火灾,因此通常需要加入阻燃剂,而应用最广的卤系阻燃剂高温下会遇热分解,放出大量的烟和有毒的腐蚀性气体,在火灾发生时容易引发二次灾害和环境污染。统计表明,80%以上的火灾死亡与吸入有毒烟雾有关。而三聚氰胺泡沫塑料自身具有很好的阻燃性能,无需…     

三聚氰胺甲醛树脂泡沫生产工艺及技术改进

三聚氰胺甲醛树脂泡沫是一种以三聚氰胺为原料制取的高开孔率的三维网格结构的新型环保泡沫塑料,具有吸音、阻燃等众多优异性能。本文介绍了三聚氰胺甲醛树脂泡沫的理化性能、国内外技术发展情况、以及实验室和工业制备方法。最后针对三聚氰胺甲醛树脂泡沫连续化生产的要求,改进了生产工艺流程和反应器。     

挤塑机电机驱动系统设计及控制研究

在简述了市场上现有塑料挤出机的应用现状和问题的基础上,分析了塑料挤出机驱动系统的特点及设计要求,确定了直驱低速永磁电机的工作参数和结构参数,提出了电机关键参数的选择和结构设计的依据,建立了控制系统的结构和设计思路,从主程序和电机控制子程序两方面分析了控制系统的工作流程。     

尼龙6的双螺杆反应挤出工艺

介绍了国内尼龙 6的双螺杆反应挤出工艺。通过己内酰胺阴离子型快速聚合 ,直接反应成型制取高性能尼龙 6 ,具有生产连续 ,周期短 ,产品性能好的优点。反应挤出生产的尼龙 6相对粘度可达 4 2～ 5 0 ,拉伸强度、弯曲强度、缺口冲击等性能均优于传统工艺生产的尼龙 6。对双螺杆反应挤出机的工艺要求及特点作了简介。     

HDPE管材专用树脂的开发

研究了高密度聚乙烯(HDPE)树脂的反应工艺条件与产品物性的对应关系,通过分析反应压力、反应温度、共聚单体和停留时间对产品性能的影响,确定了生产HDPE管材专用料YEM4803T的工艺参数,工业化生产了YEM4803T产品,对该产品进行了物性测试和加工应用试验。结果表明,YEM4803T加工流动性能和物理性能优良。     

国外动态

塑木复合材料专用挤出机美国Cincinnati Extrusuon(辛辛那提挤出)公司设计和生产出符合塑木复合材料(WPC加工要求的专用挤出机系列产品Fiberex T,现有6种尺寸规格产品和30种组合用不同构型螺杆,包括可生产木纤维含量达8 5%的汽车内饰件专用机型。其特点为加长的高效脱气加工单元,机筒和螺杆。材料均采用耐腐蚀合金,有些加工单元和部件来自该公司其他型号的挤出机。而美国Cincinnati Milacron(辛辛那提·米拉克龙)公司则推出了据称是世界上最大的WPC配混用锥型双螺杆挤出机TimerEx TC91。TimerEx系列产品包括大型锥型和平行双螺杆挤…     

同向双螺杆挤出机在聚合物脱挥中的应用研究

综述了聚合物脱挥设备的分类和基本情况,并着重介绍了双螺杆挤出机在聚合物脱挥领域中的应用、优点、国内外发展概况及发展趋势等,同时在大量工业化应用的基础上提出了切实可行的同向双螺杆挤出机脱挥工艺,并详细分析了同向双螺杆挤出机主要零部件的设计要求和设计方法。     

Theoretical model for non-intermeshing twin screw extruders

A simple theoretical model for flow in nonintermeshing twin screw extruders has been derived. The assumptions which in single screw extruders result in the “two parallel plates” model, in twin screw extruders result in the “three parallel plates” model. The flow rate equation can be expressed, for Newtonian fluids, in terms of drag and pressure flow terms, as in single screw extrusion theory, but each term is multiplied by a geometrical factor. This factor incorporates the effect of one screw on the drag and pressure flow terms of the other. The theoretical model was experimentally verified on a 1 inch diameter Bausano twin screw extruder.     

双锥型螺杆挤出机固体输送离散元分析

利用EDEM软件对一种普通锥形和两种双锥型螺杆挤出机固体输送段进行模拟.分析了高密度聚乙烯(PE-HD)颗粒在锥形双螺杆挤出机内的运动状态和分布规律.对比分析了3种锥形螺杆挤出的质量流速率、填充率、平均速度、平均压力、平均剪切应力和力矩等参数,给出了普通型和双锥型螺杆挤出机固体输送机理以及主要影响因素.结果表明,相比于...     

Different torque meets specific compounding requirements

Co-rotating twin screw extruders from Maris feature a number of technological innovations. Maris' two production lines — TM-HT and TM-MW — have the same screw geometry but they have different specific torque. This means for the same screw speed, the TM-HT can offer an increase in productivity. The company explains that the gearbox on the TM-HT extruders has been designed to give high specific torque and fast screw rotation. The maximum screw rotation speed is 1300 rpm (650–1300 rpm) and specific torque is 21 Nm/cm³. The specific torque offered by the TM-MW is 18 Nm/cm³.This is a short news story only. Visit www.addcomp.com for the latest additives and compounding industry news     

Analysis and experimental evaluation of twin screw extruders

Twin screw extruders can he classified according to their geometrical configuration. The main distinction is made between intermeshing and nonintermeshing extruders. Another distinguishing characteristic is the sense of rotation. The most important characteristics of the various twin screw extruders are examined, with particular emphasis on the effect of screw geometry on the conveying characteristics. A brief review is given of the state of the art in theoretical analysis of twin screw extruders. Experiments with two lab scale, intermeshing twin screw extruders are described, one co- and one counterrotating. Results are presented on power consumption, residence time distribution, and mixing characteristics of the two extruders. The counterrotating extruder exhibits a narrower residence time distribution and better dispersive mixing capability. The corotating extruder showed a better distributive mixing capability. These results can be explained in terms of the conveying and mixing mechanisms in both extruders. The overall extruder performance seems to be dominated by the effect of the intenneshing region. Any realistic, theoretical analysis of twin screw extruders should be centered around the flow behavior and mixing characteristics of the intermeshing region. The corotating extruder appears to be best suited for melt blending operations, while the counterrotating extruder seems to be preferred in operations where solid fillers have to be dispersed in a polymer matrix.     

Scale-up rules for mixing in a non-intermeshing twin-screw extruder

Various scale-up rules and theories have been presented for extrusion, including both single- and twin-screw extruders. Until now, however, most of these theories have concerned fully-filled channels, not only for twin screw extruders of the co-rotating fully intermeshing type (COTSE) or non-intermeshing counter-rotating type (NITSE), but single screw extruders as well. As the demand for distributive mixing and devolatilization devices increases, more and more nonintermeshing twin screw extruders with regions of partially-filled channels are being used. Therefore, developing scale-up rules for such screw extruders is imperative. In this paper, scale-up rules are developed, theoretically and experimentally, by examining the relationship between distributive mixing and important flow parameters. Two partially-filled NITSE's, with screw diameters of 0.8 and 2 inches, have been studied by using a flow visualization technique entailing a dye tracer to study the effects of distributive mixing by varying such parameters as: percentage of drag flow, screw stagger, and screw velocity. Qualitative evaluation of the spread of the dye with the number of screw revolutions was obtained from videotape of the experiments. Factorial experimental design method has been applied for evaluating these results. Finally, new scale-up rules were developed and compared with rules in the literature.     

Mechanisms of mixing in single and co-rotating twin screw extruders

Previous experimental studies have revealed that the mixing efficiencies of widely used continuous processors such as the single and twin screw extruders depend on the types of screw elements, which are utilized. It is generally recognized that the basic single screw extruder and the fully-fighted sections of the fully-intermeshing co-rotating twin screw extruders are not efficient mixers, in contrast to the specialized mixing elements such as the kneading discs used in co-rotating twin screw extruders. However, no simulation techniques were available to characterize quantitatively and rigorously the mixing efficiencies of continuous processors. In this study, we have solved the three-dimensional equations of conservation of mass and momentum, and utilized various tools of dynamics to analyze the mixing occurring in single and co-rotating twin screw extruders. It is shown that simulation methods can indeed capture the relative differences in the mixing mechanisms of continuous processors like the single and twin screw extruders. The ability to distinguish quantitatively between the distributive mixing capabilities of various continuous processors should facilitate numerical testing of new continuous mixer designs, optimization of operating conditions and geometries of existing mixers and the material-specific design of new mixers.     

双向拉伸聚酯薄膜回收挤出造粒机组的改进

同向双螺杆挤出机在聚合物的加工中得到了广泛的应用。本文分析了配置国产同向双螺杆挤出机的双向拉伸聚酯薄膜BOPET回收挤出造粒机组在使用过程中出现的问题,提出了改进措施。     

双螺杆挤出机的进展及其应用

着重介绍日本新型双螺杆挤出机的最新研制和开发的机型,评述新型双螺杆挤出机的特点,特别是新近开发的SCR双螺杆挤出机、BIVOLAV双螺杆挤出机、HTM双螺杆挤出机、TEX双螺杆挤出机、高剪切型双螺杆挤出机、格子形叶的双螺杆挤出机、新AP型双螺杆挤出机的结构、性能及其应用,提出今后双螺杆挤出机发展前景及方向。     

Mixing mechanism of three‐tip kneading block in twin screw extruders

In recent years, twin screw extruders have been applied to various kinds of polymer processing. It has been important to find their optimum geometrical configurations and operational processing conditions for the best performance of extrusions and products. Many engineers have been evolving numerical and the experimental methods to characterize the mixing performance for twin screw extruders. We have carried out three‐dimensional flow simulations of kneading blocks in intermeshing co‐rotating twin screw extruders by using the finite element method to quantify their ability in distributive and dispersive mixing. We discuss their performance in distributive mixing for three different type of kneading blocks in terms of the residence time distribution and the nearest distance between markers at various periods of time, by using the marker tracking method. Those numerical techniques and applications of mixing indices have enabled us to quantify and evaluate their abilities in distributive mixing of kneading blocks in twin screw extruders.