滚塑成型技术

随着滚塑成型工艺的发展，滚塑制品的应用范围不断扩大，目前滚塑制品的应用已经十分广泛。本文详细介绍了滚塑成型工艺的原理、优势、工艺、设备等。[编者按]     

滚塑成型的进展

滚塑成型是用粉末塑料或液体塑料来生产中空制品。本文阐述了它的成型特点，对原料的要求以及加热、冷却方法等。并详细介绍了最近几年关于滚塑成型的一些研究。     

国内外滚塑工艺发展概况

1 引言。塑料及其复合材料的加工成型工艺有很多种,除了我们常见的挤出成型、注射成型,吹塑成型等工艺外,滚塑也是塑料制品的一种加工方法。过去,由于各种因素,如较慢的加工周期及所用材料的限制,使滚塑工艺发展速度低于其他塑料成型加工行业。在各类有关塑料加工成型的资料信息中涉及到滚塑成型的资讯寥寥无几。在世界十大图书馆之一的上海图书馆,输入主题词“滚塑”,     

聚乙烯滚塑工艺及设备

详细叙述了聚乙烯滚型工艺原理和ＲＳ－１６型滚塑机结构特点,讨论了滚型工艺对聚乙烯树脂特性的要求和聚乙类滚型工艺参数对制品性能的影响,提出滚型用的聚乙烯树脂必须符合下列条件,熔体流动速率在４－６ｇ／１０ｍｉｎ,密度国０．９２～０．９４ｇ／ｃｍ＾３,平均粒径５００μｍ树脂颗粒形状为圆柱体。     

滚塑成型技术及发展趋势

概述了滚塑成型技术的基本原理、工艺特点,介绍了滚塑成型的设备和模具,展望了滚塑成型技术的发展趋势。     

滚塑成型新论

滚塑成型最大的优点之一是模具成本相对较低。由于在制造过程中不存在任伺压力,模具不需要象其它工艺要求的那样成本高、结构复杂。所用材料可以产生只有滚塑成型才有的效果,能生产出一些表观极好的制品,一种制品可以,日用一种聚合物制造,这对回收工艺是理想的。     

滚塑成型工艺与设备发展状况

1 滚塑成型工艺及其优势 滚塑是中空塑料制品成型的一种工艺方法，又称旋转成型、旋转模塑或回转成型。滚塑过程是将塑料粉末加入模具中，然后加热模具并使之沿相互垂直的两根轴连续旋转，模具内树脂在重力和热量的作用下逐渐均匀地涂布、熔融黏附于模具内表面上，从而形成所需要的形状，然后冷却模具，脱模得到制品。     

浅谈滚塑工艺在钢衬塑储罐方面的技术与应用

随着滚塑工艺的成熟发展,特别是在滚塑钢衬塑储罐以及化工防腐设备等领域的应用非常广泛,并具有强力的市场需求。这一技术的应用凸显了它的工艺结构、特点、原材料、生产设备等方面的独特优势,对产品性能、质量的稳定有了很大提高。本论文以滚塑成型工艺技术在钢衬塑产品方面的应用为分析对象,在理论与实践的基础上,对滚塑钢衬塑工艺技术、特点、原材料、成型设备、衬塑方案以及常见问题的解决方法,逐一进行了论述和总结,可为相近类型企业生产提供参考。     

滚塑成型用材料和应用市场

综述了滚塑成型发展历史、工业概况、材料、应用、市场及其动向,重点讨论了滚塑成型对材料（树脂和配混料）的要求和优缺点,比较了滚塑成型和其他中空成型方法的材料、成型、设计、模具和最终制品性能。     

Lightweight polyethylene-hollow glass microspheres composites for rotational molding technology

Innovative composites based on polyethylene (PE) filled with hollow glass microspheres (HGMs) were formulated and successfully prepared as suitable plastic materials for rotational molding technology. The HGMs here used allow to attain lightweight materials with a reduced resin content and appealing aesthetical qualities. To enhance filler dispersion and phase adhesion, thus improving the ultimate properties of the composite materials, two compatibilization strategies were adopted: namely, surface modification of HGMs by dodecyl(triethoxy)silane or addition during mixing of a maleinized PE as in-situ coupling agent. The effectiveness of the surface treatments on HGMs was assessed by attenuated total reflectance Fourier-transform infrared spectroscopy and thermogravimetric analysis investigations. PE-based composites at various HGMs contents (5, 10, and 20 wt%) were prepared by melt blending. Morphology of untreated and modified HGMs, their dispersion in the composites as well as filler/matrix adhesion were investigated by SEM microscopy. Thermal, rheological and mechanical properties of the composites were studied in comparison with neat PE. Rotational molding tests carried out both in laboratory and industrial site demonstrated the feasibility of producing lightweight plastic items (weight reduction up to 17%) of excellent aesthetics on a large scale.     

Reactive rotational molding

In order to identify the major fluid mechanical effects and catalog their domains of influence, an extensive study of flow behavior of reactive polyester resin systems in uniaxial, horizontal rotating systems has been undertaken. Four general flow phenomena are identified: cascading, where resin is withdrawn from the recirculating pool arid drains back; rimming, where resin is taken around the top of the cylinder by viscous forces; stable hydrocyst formation, where rings of fluid perpendicular to the axis of rotation are formed; and solid body rotation, where the resin on the mold wall is quite uniform and time-independent. For most flow conditions, the desired region of solid body rotation apparently can be reached only by passing through each of the other flow regimes. Experimental work on polyester resin systems is compared with theoretical studies on flow stability, hydrocyst formation, and withdrawal from quiescent pools, and suitable correlations are developed. It is noted that the current correlations for stable hydrocyst formation are invalid for polyester resins and a simpler correlation is proposed.     

Principles of rotational molding

Rotational molding is a process by which powdered or liquid plastics are converted into hollow articles. This paper is devoted to the theoretical understanding of the process of rotational molding. There are seven sections: The Art, wherein we describe the process, discuss previous attempts at understanding the process, and mention processes that are similar in principle to rotational molding. Transient Heating of Mold Surface, wherein we show that the criterion for selection of mold materials is the ratio of the thermal diffusivity to the thermal conductivity, and present the heating curve for a mold in a rotational mold machine. Melting of Plastic Powder in a Rotating System, wherein we discuss in detail those physical powder characteristics that are necessary for good flow within the mold cavity. Fluid Flow During Rotational Molding, wherein we discuss the velocity profiles within the melt film, point out that there is very little bulk polymer flow possible within the mold cavity under normal processing conditions, and consider capillary flow forces and surface wetting. Sinter-Melting, wherein we compare the Kuczynski-Neuville empirical sintering model with the Lontz viscoelastic model, conclude that the latter is correct for the sintering of materials such as ABS, and apply the Frenkel glass densification theory to the prediction of void disappearance in sinter-melt polymers. Degradation, wherein we compare our experimental tensile strengths of polystyrene, obtained at varying oven cycle times and oven set point temperatures, with values obtained from degradation models given in the literature. Laboratory Simulation of Rotational Molding, wherein we propose two series of experiments, the first series being carried out without using rotational molding equipment, and the second using rotational molding equipment with molds having relatively simple geometries.     

粉末注射成型技术的研究和应用

介绍了粉末注射成型技术的概念和工艺,包括金属粉末注射成型(MIM)、陶瓷粉末注射成型(CIM),讲述了黏结剂的使用发展情况;阐述了粉末注射成型专用注射成型机的特点,PIM粉末注射专用塑化系统,PIM专用料斗滑块装置,镶套式机筒座等,介绍了PIM技术在诸多行业中的应用,3C行业,医疗行业,汽车行业等,并展望了PIM研究的发展方向。     

塑料的滚塑成型及结构泡沫塑料成型新工艺

本文简要介绍了滚塑成型工艺过程、发展历史、优点,对用该工艺进行结构泡沫塑料生产新工艺的过程、机理及需注意的有关问题也进行了简明阐述。     

注塑成型模拟技术在注塑工艺中的应用

注塑成型工艺已经发展成为塑料工业最重要的加工手段,注射模塑过程中需要选择和控制的压力包括塑化压力、注射压力和保压压力,它们直接影响塑料的塑化和塑件质量。通过对注塑过程中所涉及的工艺条件如何影响塑料制品的质量作了探讨,借助注塑工程分析软件对塑料制品的成型过程进行模拟,合理确定这些工艺参数,并分析了一个应用CAE技术优化工艺参数的实例,提出了比较切合实际并容易提高产品质量的注塑工艺方案。     

Bubble removal in rotational molding

Closed form solutions have been obtained for bubble dissolution in typical polymer melts encountered in rotational molding. The solutions are in excellent agreement with experimental data available in the literature. Using these solutions, it is shown that under typical rotational molding conditions the polymer melts may be almost saturated. As a result, bubble shrinkage occurs over long periods. Depending on the degree of saturation, surface tension may contribute substantially to the concentration gradient that drives bubble shrinkage. It is also shown that a pressure increase imposed on a nearly saturated polymer melt leads to a steep concentration gradient at the bubble/melt interface that can cause extremely fast bubble shrinkage. Applied to the rotational molding process, such a pressure increase can result in substantial cycle‐time shortening through elimination (or reduction) of the currently used excessive heating. A further benefit may be that additional resins, which at present cannot be used because of oxidation at sustained high‐temperatures, can become available to the rotational molding industry. Under the under‐saturated conditions created by a pressure increase, the effect of surface tension on the rate of bubble shrinkage is negligible.