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

Non-Tin Heat Stabilizers for Clear rigid PVC Applications

Masumi Mizu | Taro Mitsudera | Tadashi Sengoku | Kiyotatsu Iwanami | Toshinori Yukino | Hiroshi Nishimura | Robert G. Weiler, September 2010

The purpose of this paper is to describe the development of a new class of Calcium/Zinc heat stabilizer for clear rigid PVC applications. Typically, until this time, Organo-Tin based heat stabilizers have been used for this application. Organo-Tin heat stabilizers offer excellent transparency and good heat stability protection. Recently, Butyl-Tin based heat stabilizers have been designated as an environmental Substance of Very High Concern (SVHC) in EU. This has led us to research and develop alternative heat stabilizers for clear rigid PVC applications. Liquid Barium/Zinc based heat stabilizers offer good transparency but they typically do not have enough heat stability under rigid PVC processing conditions. They also have the environmental problem of the heavy metal, Barium. Typical Calcium/Zn stabilizers have good heat stability, and are environmentally more acceptable, but typically are deficient in transparency. Our purpose in this paper is to describe a technique for selecting individual components for a high transparency powder Calcium/Zinc heat stabilizer and to demonstrate that the transparency and heat stability are suitable for the task of protecting clear rigid PVC applications. Three important technical points necessary for improving transparency were described. First is refraction (Refractive index). Second is scattering (particle size). And third is dispersion (compatibility). Ideal state satisfied these three points.

ADDITIVE PROCESSING ƒ??NEW MATERIALS FOR FUSED DEPOSITION MODELLING

Bettina Wendel , Claus M. Dallner , Ernst Schmachtenberg, May 2010

Additive processes are increasingly used to generate functional components in almost any geometry layer by layer directly from CAD-files without using tools and molds. Within the scope of this paper it is shown how the limited variety of materials can be extended for fused deposition modelling to reach new areas of application and how these new materials are to be manufactured. First functional prototypes could successfully be produced and characterized.

ADDITIVE PROCESSING – NEW MATERIALS FOR FUSED DEPOSITION MODELLING

Bettina Wendel , Claus M. Dallner , Ernst Schmachtenberg, May 2010

PROCESSING AND PERFORMANCE OF HDPE POLYMER BLENDS INCLUDING POST CONSUMER RECYCLED HDPE

T. Beiss, C. Dallner, E. Schmachtenberg, May 2010

With the rapid increase in the market for recycled polyethylene from various sources, there is an urgent need to quantify the performance of these materials. Blends of recycled high density polyethylene (HDPE) were prepared to obtain specific mechanical properties and MFI. The results show that the MFIs had significant effect on the rheological, mechanical and phase morphology characteristics of the various blends.

VIBRATION JOINING OF FILAMENT REINFORCED THERMOSETS

T. Beiss , C. Dallner , E. Schmachtenberg, May 2010

At the Institute of Polymer Technology (LKT) a vibration joining technique was developed that offers short cycle times and represents a modification of hotmelt bonding using the machine technology from vibration welding. It is suitable to join thermoplastics with thermoset materials or thermosets using a thermoplastic interlayer by taking advantage of short cycle time and excellent lap-shear strength compared to bonding with reactive adhesives.

POLYMER FLOW ANALYSIS ON AN AUTOMOTIVE INSTRUMENT PANEL

Harsh Bhagat, May 2010

Mold filling simulations are sophisticated programs providing immense benefits for the plastics injection molding industry. The use of simulation techniques has improved the processability of large tools resulting in improved finished part quality.

POLYMER FLOW ANALYSIS ON AN AUTOMOTIVE INSTRUMENT PANEL

Harsh Bhagat, May 2010

Mold filling simulations are sophisticated programs, providing immense benefits for the plastics injection molding industry. The use of simulation techniques has improved the processability of large tools resulting in improved finished part quality.

RHEO-OPTICAL MEASUREMENTS IN MICROMOULDING

B.R. Whiteside , R. Spares , P.D. Coates, May 2010

Flow visualisation has previously been used to study injection moulding. The smaller length scales associated with micro-moulding allow some additional measurements to be taken but pose new challenges due to the lower filling and cooling times. We have developed an experimental toolset for visual observation in micromoulding cavities via a sapphire window system that allows the study of mould filling post filling shrinkage of the polymer away from the cavity surface and determine the evolution of birefringence during solidification.

RHEO-OPTICAL MEASUREMENTS IN MICROMOULDING

B.R. Whiteside , R. Spares , P.D. Coates, May 2010

Flow visualisation has previously been used to study injection moulding. The smaller length scales associated with micro-moulding allow some additional measurements to be taken, but pose new challenges due to the lower filling and cooling times. We have developed an experimental toolset for visual observation in micromoulding cavities via a sapphire window system that allows the study of mould filling, post filling shrinkage of the polymer away from the cavity surface, and determine the evolution of birefringence during solidification.

SHEAR STRESS AND MELTING FLUX FOR POLYCARBONATE RESINS

Atakan Altnkaynak , Mahesh Gupta , Mark A. Spalding , Sam L. Crabtree, May 2010

Frictional forces (for temperatures less than the melting or devitrification temperature) and shear stresses are keys to the solids conveying and melting processes in plasticating single-screw extruders. For most processes the shear stress at the polymer-metal interface however is unknown. This paper presents shear stresses and melting fluxes for three polycarbonate (PC) resins with different melt flow rates. The data are related back to the extrusion process.

EVALUATION OF FATIGUE LIFE PREDICTION MODEL FOR GFRP COMPOSITE MATERIALS

Shen Changyu, Zhou Yingguo, Chen Jingbo, May 2010

A fatigue life prediction model for GFRP composites using the internal strain energy release rate as the damage metric for predicting fatigue life from a minimum of empirical data points has been proposed. This evaluation of the modelƒ??s accuracy demonstrates its simplicity and ability to model fatigue life for coupons and components. The model was able to fit fatigue data and predict fatigue life to within 5% log error with a high success rate.

LIFETIME PREDICTION OF PLASTIC PIPES FOR GAS DISTRIBUTION AND HOT WATER SUPPLY

Hiroyuki Nishimura, Takafumi Kawaguchi, May 2010

This paper describes a comparison of the lifetime of polyethylene (PE) pipes between actual field failures and accelerated experimental failures for gas distribution. The results of deformation behavior of PE pipes are also indicated in differential settlements and earthquakes. The lifetime of plastic pipes for hot water supply and space heating were also evaluated by the stress rupture tests. A 30-year-or-more service life of the system for central heating will be guaranteed at 90 degrees C under an inner pressure of 0.25 MPa.

A STUDY OF THERMALLY AND FLOW INDUCED RESIDUAL STRESSES IN INJECTION MOLDING

Yu-Te Liao , Shi-Chang Tseng , Meng-Chih Chen , Chao-Tsai Huang , Yuan-Jung Chang, May 2010

During the injection molding process mold filling may introduce residual stresses. And the sequential cooling process may result in thermal stresses. Some cases show flow induced residual stresses dominate the final stresses. Sequential multi-component molding is one of good examples of thermal stresses. On the other hand in the higher speed injection molding cases higher shear stresses may be the major contribution to final residual stresses.

EFFECTS OF STEAM EXPLOSION CONDITIONS ON THE MECHANICAL PROPERTIES OF LDPE/COTTON BAST COMPOSITES

Emad Abdalla, Remon Pop-Iliev, May 2010

The effects of cotton bast (CB) content and steam explosion parameters (including steam pressure, holdup time, and moisture content) on the mechanical properties of low density polyethylene (LDPE)/CB composites were investigated. The results show that LDPE/steam exploded cotton bast (SECB) composites show superior tensile and flexural properties compared with pure LDPE and LDPE/unmodified CB composites. The superficial area of CB is increased by steam explosion pretreatment, thus enhancing the mechanical properties of composites.

ELECTRICAL, THERMAL, AND TENSILE BEHAVIOR OF CARBON NANOTUBE/POLYCARBONATE COMPOSITES

Jeffrey Galloway, Mingjun Yuan, Rich Hoffman, Sanjiv Bhatt, May 2010

Carbon nanotubes (CNT) are effective at increasing the electrical conductivity of polymers at low loading levels without compromising the resulting composite's mechanical properties. In this study, varying amounts (2 to 8 wt%) CNT were added to polycarbonate and the resulting composites were tested for electrical, thermal, and tensile behavior. The percolation threshold was < 1.4 vol % CNT. The addition of CNT to polycarbonate increased the composite electrical and thermal conductivity and tensile modulus.

SLIDING WEAR OF POLYMERS: REVIEW OF MECHANISMS TEST METHODS AND EXPERIMENTAL DESIGN

Jeffrey Galloway , Mingjun Yuan , Rich Hoffman , Sanjiv Bhatt, May 2010

An overview of sliding wear testing of polymers is presented. The primary wear mechanisms for polymers are reviewed. Common wear test methods and other experimental design considerations are discussed. In addition metrics for comparing the wear performance of materials and their advantages and disadvantages are discussed. Since the results of wear testing depend on many different variables careful experimentation is required to obtain meaningful data.

DYNAMIC TEMPERATURE MEASUREMENT IN POLYMER PROCESSING

V. Schöppner , E. Enns , K. Anger , E. Giese, May 2010

The use of a fast responding infrared thermometer enables to measure the mass temperature inside the screw channel and the resultant profile over the screw length during the plasticizing process. With a response time of 10 milliseconds this IR-Thermometer is more than 1000 times faster than conventional thermometers.

BEYOND THE BLING: THE DEVELOPMENT OF DECORATIVE PVD/UV COATING SYSTEMS

Paul Mills, May 2010

Several market and technological developments occuring at the same time are resulting in a surge of interest and development of systems that utilize both decorative physical vapor deposition (PVD) and coatings that utilize ultraviolet light curing mechanisms.

REBUILDING A PLASTIC ENGINEERING CAREER IN YOUR FOURTH DECADE

James Gavin, May 2010

Downsizing is affecting technical employees in mature industries, such as plastics. This paper examines the statistical probability of being impacted by these organizational changes. Strategies are presented to plan for the financial, professional and emotional impacts. If properly planned, rebuilding a technical career can be a rewarding experience.

A COMPARISON OF VELOCITY TO PRESSURE TRANSFER CONTROL STRATEGIES FOR INJECTION MOLDING

Art Schubert, May 2010

Injection molders commonly use a ram position setting to control switchover. As in-mold sensors have become more widespread, using them to control switchover ensures more consistent part quality than machine-based control.Herein we explore several control strategies applied to an array of different mold configurations and materials.We evaluate each method's ability to minimize in-cavity variation when material viscosity changes. The results provide the molder with information for choosing a control strategy appropriate to each application.