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
EXTRUSION FOAMING OF HIGH-MELT-STRENGTH PP WITH SUPERCRITICAL CARBON DIOXIDE I: CELL NUCLEATION BEHAVIORS
Taher Azdast , Eung Kee Lee , Kyung-Min. Lee , Chul B. Park , Hani E. Naguib , Amir H. Behravesh , Elke Pachner , Andreas Praller, May 2008
This paper investigates the cell nucleation behaviors ofnon-crosslinked high-melt-strength (HMS) polypropylene (PP)foams blown with supercritical Carbon Dioxide (CO?ÿ2). Varying?ÿ?ÿ2. It was also observed that the effect of CO2on the cell density was more pronounced when low talc contentwas used?ÿ. Regardless of the amount of nucleating and blowing?ÿ?ÿ. It also appeared that?ÿthe die pressure did not affect the cell density significantly.agent the cell density was significantly improved by using a diewith a high pressure-drop-rate geometrythe talc and CO2 content changed the cell density. The effect ofdie pressure and pressure drop rate on cell nucleation behaviorsof HMS PP was also observed by using different die geometries.Three dies were deliberately designed to have either differentpressure drop rates while having the same die pressure or withdifferent die pressures while having same pressure drop rate.Experimental results indicated that regardless of the die theeffect of talc on the cell density was more significant at a lowconcentration of CO
RHEOLOGICAL PROPERTIES OF LONG CHAIN BRANCHED POLYETHYLENE MELTS AT HIGH SHEAR RATE
Jaejwan Kim , Dong Hak Kim , Younggon Son, May 2008
Capillary extrusion experiments involving a number of polyethylenes with emphasis on assessing the effect of long chain branching are performed. None of the metallocene catalyzed linear low density polyethylenes (mLLDPE) produced by Dow Chemicals which are believed to have some level of long chain branching show temperature dependence on the viscosity at the gross melt fracture regime. Furthermore these materials do not show spurt or stick-slip flow in contrast with most linear polyethylenes. LDPE and blends of LDPE with linear polyethylenes also show the absence of stick-slip flow but temperature dependence on the viscosity. From these observations we conclude that the stick-slip flow is very sensitive to the existence of long chain branching and the behavior of the stick-slip flow can be used as an indicator of LCB.
RHEOLOGICAL PROPERTIES OF LONG CHAIN BRANCHED POLYETHYLENE MELTS AT HIGH SHEAR
Jaejwan Kim , Dong Hak Kim , Younggon Son, May 2008
Capillary extrusion experiments involving a number of polyethylenes with emphasis on assessing the effect of long chain branching are performed. None of the metallocene catalyzed linear low density polyethylenes (mLLDPE) produced by Dow Chemicals, which are believed to have some level of long chain branching, show temperature dependence on the viscosity at the gross melt fracture regime. Furthermore, these materials do not show spurt or stick-slip flow, in contrast with most linear polyethylenes. LDPE and blends of LDPE with linear polyethylenes also show the absence of stick-slip flow, but temperature dependence on the viscosity. From these observations, we conclude that the stick-slip flow is very sensitive to the existence of long chain branching, and the behavior of the stick-slip flow can be used as an indicator of LCB.
BULK RESIN DENSITY AND PLASTICITY FOR PET AND LDPE
Stephen J. Derezinski, May 2008
The compression of the solid resin feed in the extrusion process increases its density to form the solid feed plug. Laboratory measurements were made of the density of the resin feed as a function of stress for PET and LDPE resins. Also the densities upon release of the stress were recorded and they showed that PET resin remains significantly more compressed than does the LDPE resin. The LDPE resin is more elastic and this difference is postulated to be a factor in the mechanics of the solid plug melting and flow stability. Supportive extruder stability data are cited shown and analyzed.
SIMULATION OF SCREWS FOR INJECTION MOLDING
Dr. Jiri Vlcek , Luke Miller , CT Huang, May 2008
This paper deals with the simulation of the plastification unit (extruder) for the injection molding process. It shows the theory and how the method of simulation of an extruder for the extrusion process is modified to cover the effects in injection molding mainly the facts that the screw stops rotating for a certain time and it moves backward while rotating and melting the polymer. To see the quality of the prediction of such a modified program a set of experiments was performed. A comparison of the results of these experiments with the program prediction will be shown. The presentation will also cover the most important variables to be checked for achieving good melt delivery performance in the injection molding process.
SIMULATION OF SCREWS FOR INJECTION MOLDING
Dr. Jiri Vlcek , Luke Miller , CT Huang, May 2008
This paper deals with the simulation of the plastification unit (extruder) for the injection molding process. It shows the theory and how the method of simulation of an extruder for the extrusion process is modified to cover the effects in injection molding, mainly the facts that the screw stops rotating for a certain time and it moves backward while rotating and melting the polymer. To see the quality of the prediction of such a modified program, a set of experiments was performed. A comparison of the results of these experiments with the program prediction will be shown. The presentation will also cover the most important variables to be checked for achieving good melt delivery performance in the injection molding process.
AN ESTIMATE OF LONG SERVICE TERM FOR GRP PRODUCTS
Valery G. Makarov , Rakhil M. Sinelnikova, May 2008
The long service term of GRP products such as technological pipes ducts scrubbers etc. is determined by the chemically resistant layer of multilayered fiberglass which is in direct contact with the technological environment. The diffusion of technological medium into the structure of the GRP leads to a change in the dielectric properties of the material. These changes can be used to predict the long service term of GRP products under the influence of technological environment. The ability to predict the residual life period of GRP products and results of the pipe operation with the partially damage of the chemical resistant layer under conditions of the sulfuric acid production are considered.
AN ESTIMATE OF LONG SERVICE TERM FOR GRP PRODUCTS
Valery G. Makarov , Rakhil M. Sinelnikova, May 2008
The long service term of GRP products such as technological pipes, ducts, scrubbers, etc. is determined by the chemically resistant layer of multilayered fiberglass, which is in direct contact with the technological environment. The diffusion of technological medium into the structure of the GRP leads to a change in the dielectric properties of the material. These changes can be used to predict the long service term of GRP products under the influence of technological environment. The ability to predict the residual life period of GRP products and results of the pipe operation with the partially damage of the chemical resistant layer under conditions of the sulfuric acid production are considered.
BENEFITS OF AN ENERGY USAGE INDICATOR FOR INJECTION MOLDING SIMULATION
Paul Brincat , Russell Speight, May 2008
With growing concern regarding our environmental impact greater focus has been placed on ways we can reduce our impact by improving our decisions designs and processes. The use of injection molding simulation has been shown to reduce material consumption reduce production scrap assist in recycling existing materials create better quality products that have a prolonged life and reduce energy consumption required during the manufacturing process. This paper will present the benefits of an additional measure called an Energy Usage Indicator that can assist part designers using injection molding simulation to easily identify the processing requirements of a polymer material.
BENEFITS OF AN ENERGY USAGE INDICATOR FOR INJECTION MOLDING SIMULATION
Paul Brincat , Russell Speight, May 2008
With growing concern regarding our environmental impact, greater focus has been placed on ways we can reduce our impact by improving our decisions, designs and processes. The use of injection molding simulation has been shown to reduce material consumption, reduce production scrap, assist in recycling existing materials, create better quality products that have a prolonged life and reduce energy consumption required during the manufacturing process. This paper will present the benefits of an additional measure, called an Energy Usage Indicator, that can assist part designers using injection molding simulation to easily identify the processing requirements of a polymer material.
RHEOLOGY AND STRUCTURE OF FILLED PROPYLENE/ETHYLENE COPOLYMERS
Paula Wood-Adams , Arkady Fatseyeu , Cheng Huang , Teresa Karjala , Patricia Ansems, May 2008
We have studied a new family of propylene/ethylene(P/E) copolymers produced by The Dow ChemicalCompany which allow high filler loadings whilemaintaining good processability. Our goal was to providea fundamental understanding of the unexpectedly lowviscosity exhibited by these materials when filled withparticulates. We propose that in these copolymers interfacial slip (between the particles and the polymermelt) is enhanced by the presence of a thin layer of lowviscosity polymer around the particles. The formation ofthis layer is surface tension driven and can occur insystems such as these copolymers which are homogeneousin the bulk. Such behaviour has been observed with blockcopolymersand blends; this study is the first time it hasbeen observed in an industrial copolymer of this type.
ITERATIVE LEARNING CONTROL OF MOLD-OPEN POSITION IN INJECTION MOLDING
S. Y. Mo , Y. Yang , F. Gao, May 2008
Mold-open position (MOP) is an important variable in the injection molding machine (IMM) control system. A precise control of mold open position can improve the process stability. This paper demonstrates that the variation of mold-open offset which is the key problem in moldopen positioning. Iterative learning estimator (ILE) is used in batch direction to estimate this offset. To guarantee the repeatability of this offset an Iterative Learning Control (ILC) scheme is applied to control the mold-open velocity to achieve a relatively low and stable value around the end of mold-open. The control result shows that the combined system of ILE and ILC can obtain precise MOP.
ITERATIVE LEARNING CONTROL OF MOLD-OPEN POSITION IN INJECTION MOLDING
S. Y. Mo , Y. Yang , F. Gao, May 2008
Mold-open position (MOP) is an important variable in the injection molding machine (IMM) control system. A precise control of mold open position can improve the process stability. This paper demonstrates that the variation of mold-open offset, which is the key problem in moldopen positioning. Iterative learning estimator (ILE) is used in batch direction to estimate this offset. To guarantee the repeatability of this offset, an Iterative Learning Control (ILC) scheme is applied to control the mold-open velocity to achieve a relatively low and stable value around the end of mold-open. The control result shows that the combined system of ILE and ILC can obtain precise MOP.
RESEARCH OF CONVEYING CHARACTERISTICS OF POLYMER VANE EXTRUDER
Qu Jinping , Yin Xiaochun , He Hezhi , Zhang Guizhen, May 2008
The working principles of vane extruder are entirely different from screw extruder. Materials were conveyed and plasticized by a group of vanes and the materials suffered mainly normal stress during processing. The heat history and mechanical history that the materials suffered were greatly decreased contrast to screw extruder. In this paper working principles of the vane extruder were introduced in detail. Experiments were carried out on the vane extruder to study the conveying characteristics and the experimental results were presented. Experimental results showed that the specific energy consumption is low and the change of material’s properties has little effect on throughput.
RESEARCH OF CONVEYING CHARACTERISTICS OF POLYMER VANE EXTRUDER
Qu Jinping , Yin Xiaochun , He Hezhi , Zhang Guizhen, May 2008
The working principles of vane extruder are entirely different from screw extruder. Materials were conveyed and plasticized by a group of vanes and the materials suffered mainly normal stress during processing. The heat history and mechanical history that the materials suffered were greatly decreased contrast to screw extruder. In this paper working principles of the vane extruder were introduced in detail. Experiments were carried out on the vane extruder to study the conveying characteristics and the experimental results were presented. Experimental results showed that the specific energy consumption is low and the change of materialƒ??s properties has little effect on throughput.
KOAX-S-TRUDER – A NEW FLEXIBLE AND HIGH EFFICIENT PLASTICATING CONCEPT
Johannes Wortberg , Marcel Grossmann, May 2008
A way to get high and constant plasticating capacities without using larger screw diameters or longer processing units can be reached with a new alternative plasticating concept. Using a separate driven coaxial feeding screw the decrease of throughput rate especially for materials with varying physical properties and higher screw speeds can be reduced in a wide range. The separation of solid material and melt within the short transition zone leads to high plasticating capacities and lower melt temperatures by reducing the induced shear energy caused by the rotating screw at higher screw speeds.
KOAX-S-TRUDER A NEW FLEXIBLE AND HIGH EFFICIENT PLASTICATING CONCEPT
Johannes Wortberg , Marcel Grossmann, May 2008
A way to get high and constant plasticating capacities without using larger screw diameters or longer processing units can be reached with a new alternative plasticating concept. Using a separate driven coaxial feeding screw the decrease of throughput rate especially for materials with varying physical properties and higher screw speeds can be reduced in a wide range. The separation of solid material and melt within the short transition zone leads to high plasticating capacities and lower melt temperatures by reducing the induced shear energy caused by the rotating screw at higher screw speeds.
DEVELOPMENT OF NOVEL BAYBLEND FR BLENDS WITH IMPROVED FLAMMABILITY AND HYDROLYSIS RESISTANCE
Marina Rogunova , Jim Mason , Thomas Eckel, May 2008
Bayer MaterialScience has commercialized a third generation of flame retardant PC/ABS blends. The third generation Bayblend® FR resins based on Chlorine Bromine Antimony oxide free technology complies with Blue Angel and White Swan requirements and has a UL94 flammability performance of V0 at 1.5 mm and 5VA rating at 3.0 mm. Bayblend® FR 3010 resin is a typical representative for a non-reinforced flame resistant polycarbonate/ABS blend. This product exhibits a good balance of flow stiffness impact performance chemical resistance and heat distortion properties. Most key properties of the new Bayblend® DP 3008HR resin are similar to those of Bayblend FR 3010. The key property of Bayblend® DP 3008HR resin is improved hydrolytic resistance. The new Bayblend® DP FR 3041 grade exhibits an excellent impact performance together with outstanding flammability ratings (V-0 at 0 75 mm and 5VA at 2.3mm) which makes Bayblend® DP FR 3041 resin an ideal candidate for a wide variety of thin wall applications. Bayer MaterialScience has commercialized a thirdgeneration of flame retardant PC/ABS blends. The thirdgeneration Bayblend?ÿ?? FR resins based on Chlorine ?ÿ?ÿ?? FR 3010 resin is a typical representative for?ÿ?ÿ?? DP?ÿ?ÿ?? DP 3008HR resin is?ÿ?ÿ?? DP FR 3041 grade exhibits an?ÿ?ÿ?? DP FR 3041 resin an ideal?ÿcandidate for a wide variety of thin wall applications.excellent impact performance together with outstandingflammability ratings (V-0 at 0 75 mm and 5VA at 2.3mm)which makes Bayblendimproved hydrolytic resistance.The new Bayblend3008HR resin are similar to those of Bayblend FR 3010.The key property of Bayblenda non-reinforced flame resistant polycarbonate/ABS blend.This product exhibits a good balance of flow stiffness impact performance chemical resistance and heat distortionproperties.Most key properties of the new BayblendBromine Antimony oxide free technology complies withBlue Angel and White Swan requirements and has a UL94flammability
ADVANCED PROCESS CONTROL FOR INJECTION MOLDING BASED ON CAVITY PRESSURE
Walter Michaeli , Andreas Schreiber, May 2008
The manufacturing of complex and high-grade molded parts in the injection molding process places high demands on the process control. Unlike the conventional control of the injection molding process which is based on machine variables the presented advanced process control system performs an online control of the quality determining process variable ‘cavity pressure’. In the holding pressure phase it conducts an online optimization of the process based on the pvT-behavior of the used plastic material. By this means an optimal course of the process in the pvT-diagram is realized in each production cycle and thus the quality constancy of the produced parts can be considerably increased.
ADVANCED PROCESS CONTROL FOR INJECTION MOLDING BASED ON CAVITY PRESSURE
Walter Michaeli , Andreas Schreiber, May 2008
The manufacturing of complex and high-grade molded parts in the injection molding process places high demands on the process control. Unlike the conventional control of the injection molding process, which is based on machine variables, the presented advanced process control system performs an online control of the quality determining process variable ƒ??cavity pressureƒ??. In the holding pressure phase it conducts an online optimization of the process based on the pvT-behavior of the used plastic material. By this means, an optimal course of the process in the pvT-diagram is realized in each production cycle and thus, the quality constancy of the produced parts can be considerably increased.
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