The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Enhanced Weatherability of Exterior PVC Building Products - Part II
Low levels of acrylics are widely used as impact modifiers and processing aids for rigid PVC. At higher levels, acrylics can also significantly improve the long- term weatherability of PVC. Here we report on the ongoing results of a long-term outdoor weathering study of PVC/acrylic blends. Acrylic level, stabilizer type, and weathering location all affected the property retention of the weathered specimens. With proper formulation, the acrylic blends resulted in a significant improvement in the weatherability of the samples versus the PVC controls.
Epoxy Resins from Vegetable Oils
Epoxidized soybean oil was cured with citric acid, phthalic anhydride and Lewis acids. Lewis acid initiators and citric acid gave rubbery materials of relatively low strength and low glass transition. Aromatic anhydrides give glassy polymers when equivalent ratio of anhydride to epoxy group is used. Mechanical strength of rubbers is relatively low but that of the glassy materials is typical for plastic materials.
Evaluation of Design and Processing Parameters for Extrusion Blow Mold Pinch-Off Design
Pinch-off weld line strength is crucial in ext rusion blow molding. This experiment is intended to determine and quantify the processing parameters and design parameters that will produce the strongest weld line strength. Using a 3 level Design of Experiment (DOE) for making the test specimens, the specimens were tested for tensile strength. This data was then used as a guide for producing quality pinch-off weld lines with less guesswork.
Evaluation of Runner Design for Powdered Metal Injection Molding
It has been observed that a filling imbalance occurs with powdered metal injection molding in multi cavity molds using geometrically balanced runners. This imbalance is typically opposite to the shear induced imbalance developed n these runners with conventional plastic materials The causes and effects of this reversed condition is studied and alternative runner designs evaluated to reduce the imbalance. The alternative designs include the use of the MeltFlipper technology that has proven to solve the imbalance with conventional plastic materials.
Examination of Finite Element Analysis and Experimental Results of Quasi-Statically Loaded Acetal Copolymer Gears
An elastic-plastic finite element analysis of the quasi-static loading of two acetal copolymer gears in contact is preformed. Load verses rotation of the gear set is compared to actual experimental results. The gear geometry is modeled by plane strain elements with variable thickness between the rim and web. Gear tooth failure is modeled by both deactivating and separating elements when the tensile strength is exceeded. Failure in the tooth root is best modeled by a nonlinear approach using separating elements.
An Experimental Investigation of Screw Configuration on Temperature Rise in Single Screw-Pump Extruders
The focus of this investigation was to experimentally determine the effect of barrel rotation and screw rotation viscous dissipation inside the screw pump-extruder. The experimental results can be summarized by noting that barrel rotation generated higher temperature rise than screw rotation. Results are presented for seven screw configurations.
An Experimental Investigation of Solids Conveying - Flow Rate and Temperature Rise in Single Screw Extruders
In this paper we will discuss the construction of a new experimental device to evaluate the solids conveying parameters for a single screw extruder. We will describe the device, which works for high modulus polymers, and we will compare the difference of temperature rise and heat flux for polystyrene and polyethylene when extruded under similar conditions. For these two polymers, the effect of retarding pressure on the solid bed regarding output and barrel forces will also be investigated.
An Experimental Study of the Flows in an Energy Transfer Screw
A comparison is made between the melting, pumping, and mixing characteristics of a single-screw extruder with an Energy Transfer mixing section and a conventional screw without a mixing section. Results are given for extrusion trials, extrudate sampling, and extrusion solidification experiments performed at different screw speeds and color concentration letdown ratios.
Film Blowing of a Narrow Molecular Weight Polyethylene
Four homopolymer high density polyethylene (HDPE) resins were evaluated for their blown film properties. Film was blown in both conventional linear low density polyethylene (LLDPE) configuration and high molecular weight - high density polyethylene (HMW-HDPE) configuration. Water vapor transmission rates were reduced by nearly 50% in the HMW-HDPE configuration for the narrow molecular weight resins. Haze increased and gloss decreased for the same polymers. The broad molecular weight polymer showed only small changes in these properties.
Film Properties for Good Performance on Vertical Form/Fill/Seal Packaging Machines
Technological improvements of flexible form, fill and seal packaging machines are yielding exceptional line speeds, productivity rates and bag features. This paper discusses the evolution of vertical packaging machine development and how it has impacted plastic film properties (e.g. COF, sealing temperature range, hot tack) required for optimal performance.
Fin Assembly in Energy Management
Heat sinking in electronic components in VLSI can be any method by fin assemblies in different configuration. The periodic heating is studied using hyperbolic heat wave propagative equation complex variables. The flux reversal is studied.
Foam Injection Molding (FIM) - A New Nozzle for Fluid Injection
When processing physical blowing agents (PBA) like carbon dioxide or nitrogen in the FIM-process the treatment of the PBA/melt-system is of high importance. On the one hand it must be guaranteed that a sufficient quantity of blowing agent is solved in the polymer. On the other hand a materially and thermally homogeneous melt needs to be provided in order to achieve an even foam structure and surface in the molding.In this paper a new IKV-development for FIM with physical blowing agents using a special injection nozzle is introduced. Results of the investigations in this context will be presented.
Foaming with Microspheres in Rotational Molding
A fundamental study of the microcellular foamed structure in rotational molding was conducted by using polymer microspheres as a blowing agent. The influence of the viscosity, temperature dependence of viscosity and first normal difference of different resins on the cell morphology and the tensile properties of the foamed parts was investigated.
Fundamental Characterization of Polypropylene Extrusion
It is known industry wide that polypropylene (PP) resins plasticate in single-screw extruders at rates that are less than those for linear low density polyethylene (LLDPE) resins. The goal of this research is to show the magnitude of this rate reduction, and the physical properties related to processing that are causing the rate reduction.
Fuzzy Modeling for Injection Molded Part Quality Control
The rapid growth of the injection molding applications places a continuously higher demand for reliability and precision in injection molding control systems. There lacks still a direct closed-loop control system for the quality of the injection-molded parts, due to the lacking of a reliable quality model. In this paper, a list of the part quality attributes are first selected to represent injection-molded products quality. This is followed by the development of a quality model, suitable for closed-loop control purposes, represented in a fuzzy-logic form established through the design of experiment methods.
GE Plastics Method for Titanium Dioxide Color Measurement: A Six Sigma Approach to Improving Titanium Dioxide Color Measurement Error
The measurement of titanium dioxide color is one which has historically had a large degree of error associated with it, typically quantified as the measurement standard deviation error. The determination of this measurement error is typically obtained by performing the 6 Sigma designed experiment known as a Gage Repeatability and Reproducibility (GR& R) Study.
High Accuracy Shrinkage and Warpage Prediction for Injection Molding
Shrinkage and warpage prediction of injection molded components relies on the calculation of residual stresses developed during the molding process. We present a method for increasing the accuracy of residual stress calculation. The method is applicable to amorphous and semi-crystalline materials and is effective for both filled and unfilled materials. Results obtained using the method on 3D geometry models will be presented and compared to experimental results.
Identification of Dynamic Process Models for Polymer Extrusion
From simple step experiments, it was observed that the rate at which heat is added to a polymer extrusion process through friction forces and the system heating elements is different to the rate of natural or forced cooling. This indicates that a single model that attempts to describe both heating and cooling is inadequate for control system design. A method for finding heating and cooling models using system identification techniques is demonstrated.
Improved Material Modeling for the FEA by the Specific Use of Campus-Data
The material database CAMPUS is increasingly used as data supplier for structure simulations (FEA) in plastics product development departments. The calibration of material models with mechanical data of the database means a large expenditure, especially if different materials have to be compared. Thus, a concept is developed, which characterizes the material behavior in a large strain rate, strain and temperature range with a high automation degree. So the expenditure is considerably reduced and an improved plastics-oriented simulation is realized.
Injection Molding and Color: A Basic Look at Design, Processing, & Troubleshooting
The use of color additives in the injection molding process is one of the most effective ways to add value to molded parts. Considerations must be made, however, on how additives are measured, handled, and processed, as well as attention paid to any cross-functional features the final part may require.This paper will examine basic design considerations for adding color at the press vs. using precolored resins in terms of final costs, handling, and processing.
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