SPE Library

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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Conference Proceedings

Profiles of Mold Ejector Pin Melt Density Sensors

Frederick Buja, May 2005

Ejector pins in a two-cavity mold were retrofitted to sense injected melt flow and volume of the molding process. Two materials, two mold clamp forces, a cold runner sprue, and replaceable hot sprue bushing capability were run in an electric molding machine.Profiles of the sensed melt cavity volume and differences will be presented.

A System Analysis for Injection Molding Screw and Screw Tip

Jingyi Xu, May 2005

A system analysis for the screw and screw tip in injection molding is one of the keys to promote the machine performance. It explains several critical issues of plasticizing and injecting performances. This is a model to analyze the screw and screw tip with different materials at different machine parameters as a system and to optimize the performance in injection molding.

Increasing the Flexural Modulus of Rigid PVC at Elevated Temperatures

Henry E. Wiebking, May 2005

The use of PVC building products in hot climates has demonstrated the need for formulations that exhibit increased stiffness at elevated temperatures. Talc has been used as an additive to increase flexural modulus but this approach can produce an unacceptable drop in impact strength. This report presents the results of laboratory work designed to find ways to increase the stiffness of rigid PVC compounds at elevated temperatures while maintaining their room temperature impact performance

Computer Scale-Up Model for Desolventizing Highly Viscous Polymers in Kneader Equipment

Daniel U. Witte, May 2005

A concentrated rubber solution (less than 20 % solvent) is fed to a high volume kneader in order to remove the solvent down to ppm level. A simulation program has been developed to describe this devolatilization step.The program predicts final solvent content, the filling level and the mechanical torque build-up. The program can be used to refine process control and the scale-up of this type of process.

Comparison of Devolatilization Technologies for Viscous Polymers

Pierre-Alain Fleury, Daniel Witte, May 2005

Devolatilization of solvents from viscous polymer cement is realized through stripping of solvent with steam in stirred vessels or directly by evaporating the solvent from the polymer. The later so-called direct desolventizing is realized in extruders or high volume kneaders. All 3 methods involve additional energy to drive out solvent either by partial pressure through additional steam (steam stripping), building and releasing pressure in order to explode the polymer bulk (extruder) or dynamic surface renewal (kneader).

Concurrent Engineering Approach for Designing a Novel Plastic Pallet

Magda M. Castillo, Agustín Torres, Luis Marín, Facundo Méndez, May 2005

The concurrent engineering approach was used to design a lightweight, one-piece-tailored and very resistant pallet. Three CAD/CAE software programs were involved in the designing process. The pallet design went back and forth between the software until it was optimized and the part met all the functional, mechanical, processing, and machining requirements at the lowest pallet weight possible.

Material Selector for LLDPE/LDPE Blends for FFS Applications

Nelson Colls, Agustín Torres, Facundo Méndez, May 2005

There is a delicate balance between processability, mechanical properties and seal performance when LDPE/LLDPE blends are used. Choosing the right blend proportion is sometimes a very difficult job, and high resin and time consuming. An easy to- use selector that can run in most spreadsheet programs was devised based on DOE approach.

Properties Predictor for HDPE/LDPE/LLDPE Blends for Shrink Film Applications

Agustín Torres, Nelson Colls, Facundo Méndez, May 2005

A technique that involves design of experiments was developed to generate set of equations that predicts processing, mechanical and shrink properties of HDPE/LDPE/LLDPE blends. The results are presented in an easy-to-use spreadsheet that can be used even in pocket computers.

Effect of Ultrasonic Energy on Polymer Amalgamation

Michael D. Schulte, Lynn L. Faulkner, Richard P. Heggs, Douglas B. Pape, Micah M. Kattner, May 2005

Ultrasonic energy was demonstrated to promote amalgamation between a polymer melt and polymer solid during injection molding. Advantages include the ability to injection mold at significantly reduced temperatures while achieving favorable bond strength. In addition, ultrasonic energy promotes joining chemically dissimilar polymers, bonding to inserts, and co-molding or overmolding dissimilar polymers.

Effect of Atmospheric Plasma Treatment on the Surface Energy of Polymers

Rachel M. Thurston, John D. Clay, Michael D. Schulte, May 2005

This paper describes experiments to quantify surface energy changes on polymers after exposure to atmospheric plasma. Atmospheric plasma treatment permits the functionalization of surfaces at near-ambient temperatures. Various polymers were treated with the plasma unit, and the surface energy changes as a function of time and adhesion characteristics were monitored.

The Vented Barrier Screw

Stephen J. Derezinski, May 2005

The typical barrier screw (high efficiency screw) concept has been modified to provide for venting (devolatilizing) of polymer through a bore in the drive-end of the screw. The bore is connected to the melt channel by a vent hole in the melt-channel screw-root. The melt channel is deep so that a free surface of polymer melt and path exists to release gasses to the vent. The screw design was tested and shown to process and devolatilize PET powder, PET pellets, and PEN pellets at greater rates and with less power than a conventionally vented two-stage screw in the same extruder with the very same polymers.

Extrusion Process and Screw Design Investigation via Experiment Design and Computer Simulation

John R. Wagner, Jr., John Perdikoulias, May 2005

This paper explores the value of Design of Experiments (DOE) statistical analytical techniques and mathematical modeling of extruder behavior to characterize extrusion performance.

Improved Dispersion of Yellow Metal Azo Pigment in Polyethylene Film

Darrin Colquhoun, Helen Skelton, Mark Vincent, May 2005

Pigment Yellow 62 (PY62) is widely used in the extruded polyethylene film industry. Increasing demands for throughput, quality and reduced wastage led to the need for a new grade of PY62.Research showed that control of PY62 particle size and dispersion directly affected properties such as film transparency, colour development, extruder pressure build and processing time. Using this knowledge a new PY 62 for polyethylene film was developed and successfully tested.

A Review of Melting Mechanisms in Single Screw Extrusion

Eldridge M. Mount III, May 2005

This paper will present a review of basic melting mechanisms and the assumptions on which melting models are based. In addition a discussion of the impact of checking models with extruder model calculations vs. direct melting measurement (screw simulator). A discussion of the low screw speed mechanisms" seen lately and discuss the impact of measuring techniques controlling observations vs. the observations controlling the measurement techniques"

Observations on Field Fusion Joining of Large Diameter HDPE Pipe

Donald E. Duvall, May 2005

Large diameter high density polyethylene (HDPE) pipe has been utilized for various municipal and industrial applications for over 30 years. Butt fusion procedures developed in the earliest days of polyethylene pipe fusion are still the ones recommended for joining this pipe in the field. Analysis of recent problems with pipe fused in the field suggests that modern workers are trying to speed up the joining process by not adhering to all of the recommended procedures. These problems will be examined in detail and the implications of short cuts in the procedure discussed.

Effects of Process Conditions on Shrinkage of the Injection-Molded Part

SHEN Changyu, WANG Lixia, Li Qian, CHEN Jingbo, May 2005

Shrinkage behavior plays a critical role in determining the final shape and dimensions of an injection-molded part. In this paper, the CAE and Taguchi DOE technique were combined to investigate the influence of factors on the shrinkage behavior of the injection molded part and optimize the process conditions, the part quality was improved under the optimum process conditions obviously.

Problem Solving by Thermal Analysis in the Automotive Plastic Industry

Xiaodong Liu, May 2005

Thermal analysis studies the thermo physical and thermo chemical properties of a material. In a series of case studies, various thermal analyses, such as DSC, TGA, TGMS, DMA, and TMA were used to solve real life problems in the automotive plastic industry.

Two Solutions for Three-Dimensional Flow Simulation of Injection Molding

Wei Cao, Changyu Shen, May 2005

This work presents two methods: Dual Domain and Real 3D to simulate the flow on the solid model from CAD. Dual Domain assumes the melt flow along the dual surfaces and employs hot runners to connect the coupled nodes to keep the melt flowing uniform on the surfaces. Real 3D employs an iterative method to solve coupled pressure and velocity independently. It reduces memory needs in simulation and enhances the stability of numerical scheme. Experiments indict they are valid for certain parts.

Selecting the Right Decorating Method - Pad Printing vs. Screen Printing vs. Hot Stamping

Michael J. Learmouth, May 2005

This article will help to explain the various aspects, including strengths and weakness’ of the three primary decorating technologies that are widely utilized in the plastics molding/ decorating industry, namely; Pad Printing, Screen Printing and Hot Stamping technologies. While each technology has its place and area of competence, it is important to note that not one of these technologies is perfect for all decorating applications. So with that in mind, you may end up needing to invest in more that one or all of these useful decorating technologies.

Case Studies of Plastics Failure Related to Molecular Weight or Chemical Composition

Myer Ezrin, Gary Lavigne, Mark Dudley, Laura Pinatti, May 2005

Processability and product performance depend on having the appropriate polymer molecular weight and composition of the formulation. Failures were caused by errors of molecular weight or composition. GPC played a key role in molecular weight cases. IR spectroscopy and GC/MS were used for composition.