Injection blow molding PVC containers

This paper discusses product design, tool design, tooling, processing parameters, and machine and tool maintenance for injection blowmolding PVC containers. Product design details geometric shapes, engraving, and sharp area definition. Tool design offers pros and cons of temperature control core rods vs. conventional core rods. Tooling defines types of steel to inhibit rust. Processing parameters detail times, pressures, and temperatures to inhibit polymer breakdown that causes material burning. Machine and tool maintenance defines preventative maintenance for both, for longevity.     

提高注塑件性能的熔体振荡技术

目前有一种新开发的注射熔体振荡技术,无需添加填料和助剂,就可提高注塑部件的机械特性。这项技术还可转移、隐藏或减少部件表面的注射熔接痕,并纠正制件取向应力等缺陷。     

Injection molding electroluminescent components

This article explores the feasibility of using mass manufacture, namely injection molding, as a route to produce cost effective electroluminescent (EL) components straight from the mold tool. EL screen printing pastes were adapted and introduced into the injection molding environment as a multilayer structure. Four‐layer systems were investigated using a spray deposition method to apply individual layer components directly in‐mold. Finally, the substrate was back injected to produce a three‐dimensional illuminating device straight from the mold tool. Materials, methods, and outcomes are described, the implication being that electronic manufacture could be moved upstream and performed in‐mold with resultant cost and energy savings. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Injection molding in disk-shaped cavities

Experimental results together with predictions based on a numerical simulation are reported for the filling by injection molding of a center gated, disk-shaped cavity with acrylonitrile-butadiene-styrene terpolymer (Lustran ABS Q714) and with polypropylene (Pro-fax 6523). At a specified fractional fill, the output of a pressure transducer (Δπ_zz) near the sprue was measured and the clamp force (F) was obtained by. integrating the output of four pressure transducers over the projected area. A systematic study was made to determine the effect of the (1) material properties, (2) cavity thickness, (3) melt temperature in the barrel, and (4) injection rate on the measured and simulated values for the pressure transducer output and clamp force. For a given barrel temperature, cavity thickness and intermediate-to-high injection rates, the pressure transducer output and clamp force were found to be nearly independent of injection rate for ABS and to increase with increasing injection rate for polypropylene. As the injection rate approached zero, the pressure transducer output and clamp force increased because of the long time available for cooling the flowing melt. For ABS the simulated results were about 5-25 percent higher than experiment, whereas for polypropylene they were about 10 percent lower than experiment when the viscosity model included solidification Flow instabilities were observed to occur at conditions where the pressure transducer output curve showed a marked upturn with decreasing injection rate.     

Low temperature impact modification of injection molding PVC

To meet the stringent requirements of PVC compounds intended for use in injection molded cabinets, housings and other electrical applications, impact modifiers are required which permit good melt flow while processing and allow passage of falling ball impact at ?20°C. Extensive testing is described as differentiating the low temperature toughness imported by two similar impact modifiers which give the same mold flow in modified PVC.     

直接挤出成型加工用硬质聚氯乙烯专用树脂

在2、10和70L聚合釜中对氯乙烯悬浮聚合工艺与树脂颗料形态的关系进行了研究,对添加的助剂进行了筛选和匹配,确定了静态混合接枝聚合技术及两段悬浮聚合工艺。指出：该 用树脂生产技术特点是将PVC加工中所需的各种助剂在聚合期间全部加到聚合釜中,且非常均匀地散到PVC颗粒内部发挥相应的作用,树脂颗粒形态规整,吸油率适中,干流性好,易于加工成型;同时能有效地改善生产环境,是挤出成型加工硬质制品的理想专用树脂,对PVC工业的发展具有重要意义。     

PVC degradation during injection molding: Experimental evaluation

This paper focuses on experimental observations of poly(vinyl chloride) (PVC) degradation during injection molding. Degradation of poly(vinyl chloride) has been extensively studied. These studies have been performed in quiescent systems with very little or no strain applied to the sample. However, during processing, the polymer experiences very large deformations, in particular in the case of injection molding. This work demonstrates that the large shear during injection molding causes a significant increase of degradation as compared to studies in quiescent systems. It was also observed that degradation occurs in less than 1/10 the time required for quiescent systems. Finally, the flow geometry also affects the degradation behavior during processing. Understanding the parameters leading to degradation could lead to schemes to avoid it. J. Vinyl Addit. Technol. 10:17–40, 2004. © 2004 Society of Plastics Engineers.     

Processing conditions optimization for PVC plastisol rotational molding

In this work we present the optimization of the processing conditions for PVC plastisol rotational molding. The effects of oven temperature, processing time, rotational, speed and amount of plastisol over the degree of curing, physical appearance, and mechanical properties of the molded articles were studied. Also, using a simple mathematical model to simulate the temperature profiles of the plastisol inside of the spherical mold as a function of time, the viscosity change of the plastisol with time is reported. A rotational molding machine laboratory size was used for the experiments. The oven (at different points) as well as the mold (at the inside and outside of the cavity) temperatures were measured as a function of time in order to get a better understanding of the curing process. Such data in conjunction with the model gives the support for process optimization and control.     

Injection molding of unsaturated polyester compounds

A bulk-molding compound made of unsaturated polyester resin, glass fiber, calcium carbonate fillers, and low profile additives is studied. The viscosity of the compound in the absence of cure reaction is measured by capillary rheometry. The compound exhibits a shear-thinning behavior. Injection molding in a rectangular plaque equipped with pressure transducers shows that the crosslinking reaction can begin during mold filling for low flow rate or high mold temperature. Fiber orientation in the plaque is complex as the reinforcement appears under two aspects, bundles or filaments. Their lengths and orientations are different. A layered structure throughout the thickness is observed at the mold entrance, whereas the orientation becomes progressively unidirectional in the plaque. Two fiber-free layers near the the mold walls are observed. A numerical simulation of mold filling assuming inelastic non-Newtonian kinetic dependent behavior is presented. The results agree well with pressure measurements. A simplified decoupled fiber motion calculation is finally proposed. A qualitative explanation of the basic phenomena which induce fiber orientation is presented.     

Injection molding plant for ceramic production

An injection molding plant for the production of long ceramic articles is described, including the functional principle and operating parameters.     

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。     

PVC木塑复合材料成型技术

介绍了废旧塑料再利用技术,探讨了PVC木塑复合材料的配方、工艺、制备及木粉的处理方法。结果表明:经处理的木粉,在PVC和木粉之间形成了较高强度的界面层,使木粉与基体树脂粘接力强,改善了材料的力学性能。     

连续热压成型多彩半同质体PVC卷材地板

从原料、配方、生产设备、工艺流程、生产注意事项及工艺特点等方面介绍了一种利用平带鼓式硫化机连续热压成型半同质体PVC卷材地板的新型生产工艺,其耐磨层为多彩碎粒花样的图案。与传统的间歇式热压法相比,该工艺生产效率大大提高,设备投资少,占地面积小。     

下吹法聚氯乙烯热收缩膜的生产工艺

吹塑法制取PVC热收缩膜可分为一次成型法和二次成型法。一次成型法较二次成型法具有很多的优越性。下吹法生产PVC热收缩膜可相对实现一次成型，文中对该生产工艺的要点进行了简要介绍和总结。     

注压法和模压法对液体硅橡胶物理机械性能影响之比较

液体硅橡胶具有可成型形状复杂的制品、加工便捷高效、成本低效益好的特点研究发现,不同的成型方法对硫化胶性能几乎没有影响。     

Injection molding with an additive manufactured tool

This study examines the viability of using additively manufactured injection molding tools for short run proof‐of‐concept plastic parts by assessing the quantity and quality of molded parts. Prototyping injection molded parts traditionally can be very expensive, but with improved additive manufacturing materials and techniques such costs could be reduced. To prove this, plastic tools were made by using PolyJet and Fused Deposition Modeling out of Digital ABS, FullCure 720, and ULTEM 1010 materials in this study. The test tools were then compared to the standard P20 metal tool by molding acetal, polycarbonate (PC), and polypropylene (PP) in each tool type. The molded parts were analyzed for processing effects on part shrink, physical, and mechanical properties. Testing concluded that parts molded with additively manufactured tools performed comparably to parts made on a P20 tool. However, the quantity of satisfactory parts molded in acetal and PC were consistent with the literature at 10–100 parts. Conversely, molding in PP suggested that processing with additive manufactured tools could exceed 250 parts. POLYM. ENG. SCI., 59:1911–1918, 2019. © 2019 Society of Plastics Engineers     

Injection molding of thermotropic liquid crystal polymers

Thermotropic liquid crystal polymers consist of rod-like molecules and are often called “self reinforcing thermoplastics.” Their rheological behaviors as well as orientation development during processing are often very similar to those of short fiber-filled composites. Without reinforcement, the polymer shows superior mechanical properties to conventional glass fiber-reinforced engineering resins. The orientation distribution in the crosssection as well as flow patterns in the molded thermotropic polymers are clearly visible to the naked eye due to color differences. This makes it particularly convenient to study the orientation distribution as well as the flow patterns of packing, back flow, jetting, flow instabilities, and weld line formation in injection molding. This paper discusses physical properties of a typical ther motropic polymer and their relationship to mold filling process in the injection molding.     

Injection molding higher performance reinforced plastic composites

Conventional screw plasticizing injection molding machines (IMM) have been used to mold over 50 wt% of all reinforced plastics (RP) composite processed (1–9). Principal reinforcement used is E-glass of short glass fibers (SGF) with thermoplastics (TP) such as nylon (PA) and polypropylene (PP) (each over 25 wt% of total). Fiber lengths are usually limited to being milled to 1 mm (0.04 in); average length in molded parts are 0.3 mm (0.01 in) to 0.5mm (0.02 in); Long glass fibers (LGF) would be more desirable in obtaining better performances such as higher strength, stiffness, creep resistance, fatigue resistance and improvements in dimensional stability and thermal properties. However, fibers will degrade in length during conventional molding resulting in less efficient use of reinforcements. LGFs can start at 10 mm (0.4 in) and after IM can be in the order of at least 5 mm (0.2 in); longer fibers are also used. Special fiber impregnation techniques will permit successfully molding LGFs (1–21).     

Injection molding of polypropylene/polycarbonate blends

This work deals with the effects of material and processing parameters on the mechanical behavior and morphology of noncompatlbilized polypropylene-polycarbonate (PP-PC) blends. The blends containing between 0 and 40 vol. percent of polycarbonate were compounded using a twin screw extruder and converted by injection molding using molds with rectangular as well as dogbone shaped cavities. The blends exhibit a complex skin-core morphology which evolves with the composition. Despite the absence of interfacial adhesion, the low strain modulus increases with PC concentration and follows approximately the Takayanagi model for systems with perfect adhesion. A slight increase of stiffness and strength with increasing PP/PC viscosity ratio is also observed. Weldline strength of these blends is generally poor and decreases with the increasing PC concentration.     

Injection molding of a diffractive optical element

The injection molding of a microfeatured component, a diffractive optical element, was studied. The component has a wave‐like pattern on the surface, with amplitude 0.5 μm and wavelength 3 μm. Two different polymers were used: a polymethylmethacrylate and an ethylene‐norbornene copolymer (cyclic olefin copolymer). The topography was investigated using white light interferometry (WLI), atomic force microscopy (AFM), and scanning electron microscopy (SEM). A new WLI‐based technique is proposed for rapid quantification of the replication of periodic surface patterns. This technique gives almost the same information regarding the degree of replication as AFM but can be performed much faster. Quantitative data on the degree of replication as function of processing conditions are presented. At optimal conditions, almost perfect replication is obtained using both materials. At suboptimal conditions, it is observed that the degree of replication increases with increasing injection velocity and increasing mold temperature, with similar characteristics for both materials. The difference in replication quality between the two materials seems to be related to the different temperature dependencies of the viscosities. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers