SPE Library

Biaxial stretch blow molding is a process for producing a plastic container from a preform or parison that is stretched in both circumferential and axial direction when the preform is blown into its desired container shape. It is well established for the large scale production of high quality PET bottles with excellent mechanical and optical properties.The concept of "virtual prototyping" is nowadays well established in the stretch blow molding industry in order to improve the containers properties during the design phase. Still, a virtual optimization is yet connected with much manual work. Therefore, a process simulation and a testing simulation for stacking strength was integrated into an optimization cycle to design a preform geometry for improved mechanical properties of the corresponding bottle. The optimization performed with Newton based algorithms however lead to suboptimal mechanical properties. The investigations show, that the objective function indicating the mechanical properties of the bottle has several local maximum values which prevent the determination of a global maximum. Further investigations will focus und different optimization algorithms.

I would propose creating a summary of efforts to utilize PET in extrusion blow molding. The main processes for making PET bottles involve creating an expensive injection mold in combination with expensive blow mold tooling. This approach works for large volume production of 100million containers or more, but many potential packages for lower volume users are not well served. Resin suppliers have created grades of PET with increased melt strength that have begun to address this market need. These materials are imposing problems for recycling of PET which needs to be addressed. I think a summary paper of the activity that has taken place will be of interest to ANTEC attendees. I have not written the paper but will if the organizers wish a presentation.

In this report, we present preliminary results on the use of blow-molding simulation as a tool for optimizing processing conditions and preform / parison geometry to achieve a blow molded part with the desired thickness distribution. Simulations were carried out using the software B-SIM† in the context of stretch-blow-molding of PC injection-molded preforms for LED bulb cover applications. This application requires optical quality parts and imposes stringent requirements on tolerances for the thickness uniformity of the blow-molded cover. Baseline simulations -- with preform geometry matching that used in initial experimental trials, and employing processing conditions similar to those employed in the blow-molding trials – estimated thickness variations exceeding the tolerances imposed by the application. Virtual iterations with B-SIM† simulation trials were then employed to optimize the geometry of and initial temperature distribution within the preform, as well as the processing conditions to result in predictions of significant improvement in thickness uniformity of the blown part.

Intermittent extrusion blow molding is increasingly being used in polymer forming processes for the production of complex thermoplastic industrial parts with short cycle times. During this process residual stresses caused by inhomogeneous cooling and relaxation of polymer chains, often result in shrinkage and warpage of the final part. One challenging quality requirement of industrial blow molded parts is geometric tolerances. Therefore part deformation, due to cooling and solidification, needs to be controlled and optimized according to specific design criteria. In particular, the complex design shapes of plastic fuel tank (PFT) shells exacerbate these challenges which need to be resolved upfront, in the early stages of product development and tool design. Consequently, the development of an accurate simulation tool, well suited for industrial applications, to predict thermoplastic part deformations due to cooling and solidification, has become essential for part designers to help achieve an efficient production with minimum manufacturing cost. The aim of this work is to present the latest advancements in predicting the shrinkage and warpage deformation of a curved PFT, designed for agricultural machinery, using NRC’s BlowView software. This case study validation considers the entire blow molding stages (i.e., polymer flow in the die, parison formation, inflation, and finally in and out of mold cooling during part solidification). The simulation results, in terms of thickness distribution and displacements, are compared to an actual scanned part using the best fit technique in order to exemplify the accuracy and reliability of the modelling approach.

Fluoropolymers are well known materials in the architectural industry. Films made from these materials can be made into aesthetically pleasing building skins. But it’s a challenge to bond them to other materials.Multilayer optical film technologies can be used to manage building features while maintaining architectural aesthetics. The technology has been applied, for example, to the creation of visibly transparent IR mirror films, visible mirrors and decorative films. But not all of these are outdoor stable.3M‘s proprietary nanostructuring process allows for almost universal bonding of fluorpolymers.But a process needs to be applied to a material to become a product.

We studied the efficiency of sodium carboxy methyl cellulose (a Polymer) in the inhibition and control of corrosion of aluminum on acidic medium. Sodium carboxymethyl cellulose was diluted into five different concentration levels and applied on several prepared and polished aluminum coupons for a weight loss experiment. Metal coupons previously cleansed and weighed were totally immersed in 100ml of 0.5M solution of HCl in an open beaker. The beaker was placed in a water bath maintained at varying temperatures. The procedures were conducted with and without the various concentrations of the inhibitor (Na-CMC) at temperatures 35oC, 45C, 55C, and 65C. At every time interval, the immersed metal specimen was withdrawn from the test solution, washed, dried and reweighed. The weight loss being the difference in weight of the specimen before and after immersion in the water bath was recorded for every coupon sample.The effects of concentration, temperature and time on weight loss, corrosion rate and inhibition efficiency were studied from the various plots and from the graph, it was observed that increase in the concentration of the inhibitor increases the inhibition efficiency. Also increase in the temperature of the operating environment decease the inhibition efficiency and vice versa. The relationship between the inhibitor efficiency, IE; concentration, C; temperature, T; and time t, was established through a model IE= 58.4770C0.5148-0.8913T + 50.4194t-0.1061, the proportion of variance explained (R^2) = 0.9128 (91.28%) and the prob(t) is 0.00001. Keywords: corrosion, weight loss, aluminium, inhibition efficiency, concentration

Titanium dioxide is a common pigment used in plastic applications to provide opacity and provide protection of the polymer matrix against photo-oxidation The color and photo-durable functions of pigmentary titanium dioxide are the most relevant for plastic applications which experience exposure to wavelengths less than 700 nm and greater than 300 nm from solar or artificial light exposure, i.e. visible and ultraviolet wavelengths. TiO2 efficiency to deliver the functions of color and photo-durability is related to the TiO2 surface coating, concentration of TiO2 and certain organic stabilizer additives. This paper describes the relationship of these factors by monitoring the decay of polypropylene gloss based under accelerated exposure conditions.

The reduction of VOCs (volatile organic compounds) in polymers is becoming more important as many automotive producers and OEMs are seeking to meet stringent specifications regarding VOCs in automobile cabins. In addition, “cosmetic organoleptics” are becoming more important as polymers continue to replace other materials such as metals, and as consumers remain generally wary of polymers in their lives from a health and safety perspective. Herein, synthetic aluminosilicate polymer additives are shown, quantitatively, to reduce the VOCs/odors resultant from processing and the end-use of polymeric articles. Various gas chromatography experiments are utilized to quantitatively show the chemical species that are captured by this powerful additive, as well as human sniffing testing to qualitatively show the effects on the perceived odor. In addition to size exclusion mechanisms, this synthetic mineral additive derives its specificity from the inherent hydrophilic/hydrophobic nature of the different zeolite crystal lattices.

The versatile solid-state chemistry of Bismuth allows for a variety of coordination complexes and the generation of new and robust inorganic pigments as a result. Bismuth has been used in combination with a few inorganic elements, and is most readily found as complexes containing amines and amides, alkoxides, carboxylates, thiolates, and halides. Bismuth Nitrate is amongst one of the most common starting materials for synthesizing Bismuth complexes, and from this starting material the first Bismuth Vanadate pigments (PY.184) were formulated in 1985. There has been continued innovation in this pigment chemistry over the years, and in 2015 a groundbreaking Bismuth orange with a unique color index, PO.86, was launched (proprietary technology of DCC). Since their commercial introduction in 1990 (first production for Ciba, The Netherlands) into the coatings & plastics markets, Bismuth Vanadate pigments have increased in importance as their field of application has grown. These bright yellow, highly saturated pigments are characterized by their outstanding opacity/hiding power, chemical resistance, excellent weathering and durability. DCC’s 3rd innovative generation of Bismuth Vanadate pigments have expanded the limitations of this chemistry to cover a wider color gamut from greenish-yellow to orange hues. Advances such as improving the heat stability has increased the utilization of Bismuth Vanadate products in engineering resins e.g. Nylon 6. Increasing the color strength has created value in use for many customers who want to use less pigment whilst maintaining the hiding power within their system. Moreover, introducing Stir-In technology has helped to reduce operating costs by making the pigment easier to disperse, therefore reducing pressure rise in the extruder and reducing the number of extruder screen changes required during production. Improvements in our manufacturing technologies have allowed DCC to attain the most demanding and specific performance attributes such as heat stability & dispersibility. Through intensive research DCC has been able to introduce an exciting new inorganic pigment into the market, based on Bismuth and identified by a new color index: PO.86. This clean yellow shade inorganic orange has outstanding hiding power, typical of inorganic pigments and represents an excellent starting base for orange colour matches. Additionally, PO.86 is non-warping and has very good heat stability (up to 250 °C): it is therefore strongly recommended for use in polyolefin based plastics, and architectural, industrial, powder, automotive & coil coating applications. There are only a few options for formulators in this shade area (most of which are based on organic starting materials), but none of these alternatives have the same level of durability and opacity as PO.86. This paper will illustrate how Bismuth Vanadate and Bismuth Orange pigments compare to other colorants in the green shade yellow to orange shade areas, with particular reference to performance attributes such as heat stability, dispersibility, weather-fastness, warp resistance and reference how these products perform in different polymer systems. This presentation is thus ideal for those who work & formulate with color and would like to develop a greater understanding of how PY.184 and PO.86 pigments influence the plastics they work with.

AbstractExploring a common thread amongst car owners worldwide, color. We will look at how and why car colors are popular regionally and what drives these global markets.What are the major influences that determine whether your car color will remain as the “hot trendy color” or be outdated in a few years.We will address the evolution of a car color, from the upstream design ( could be up to 5 years) to the development of the OEM/Refinish perspective.We will also take some unique examples of color outliers that have been and will be a forcein color selection.George Iannuzzi Senior Sales Manager Sandream Impact LLC

This paper seeks to enlighten the newcomer to formulating color and additives masterbatches for thermoplastics with an overview on the issues of shrinkage and warpage. First, the two concepts will be defined and differentiated followed by a description of how they are quantified or characterized in the literature. Some of the many variables that impact warpage will be touched on after which the special role organic pigments can play will be elucidated. Finally, there will be a brief review of the recent developments in non-warping pigments and other strategies formulators use to mitigate warping.

Due to its great potential and capability, the fiber-reinforced thermoplastics (FRT) material and technology have been applied into industry recently. However, due to the microstructures of fiber inside plastic matrix are very complex, they are not easy to be visualized. The connection from microstructures to the final shrinkage/warpage is far from our understanding. In this study, we have performed a benchmark with three standard specimens based on ASTM D638 where those specimens have different gate designs. Due to the geometrical effect, the warpage behaviors are quite different for those three specimens. Although we expect long fiber reinforced to enhance strength, it causes one specimen warped downward and bended inward, another warped upward, and the other slightly upward at the same time. The difference might be due to the interaction of the entrance effect of molten plastic with fiber content to cause high asymmetrical fiber orientation distribution (FOD). Moreover, the experimental study is also performed to validate the simulation results. From short shot testing to the warpage and bending measurement for each individual model, overall, the tendency for both numerical simulation and experimental results is in a reasonable agreement. However, some deviation still existed which needs for further study.

The use of long fiber reinforced polymers in compression molding has significant advantages for application in automotive large scale production due to its suitability for cost-effective, low fiber attrition production. During processing, fiber reinforced material is compression molded into geometries with complex features like ribs, bosses and connector points. Inside ribbed structures, earlier experiments have shown significant deviations in fiber content with longer fibers. These deviations are caused by increasing fiber interaction, leading to a separation of fiber and matrix phase during flow – the phenomenon of Fiber Matrix Separation (FMS). While these early experiments have exposed the leading factors on the appearance of FMS, a deeper understanding of the observed effects is necessary. In the presented paper, experiments in compression molding with a simple ribbed plate tool are conducted. During the experiments, the initial fiber length and charge location are varied and their influence on the fiber filling during processing is investigated. Therefore, the compression molded components are investigated regarding their fiber properties with pyrolysis and CT imaging. Results show, that the fiber length is the most significant factor on FMS in complex geometries and leads to extensive FMS. Generally with longer fibers, more FMS appears. Furthermore, the initial charge position is vital for fiber behavior during filling. With the charge positioned underneath the rib, fibers are prone to display excessive bridging, leading to an increase in FMS. With longer flow paths, the fibers are able to align inside the polymer flow and are smoothly dragged into the upper rib regions with less interaction. A generous rib base radius supports the fiber access and minimizes FMS. In addition to the fiber property analysis, mechanical component tests are conducted. Test results show a significant decrease in mechanical properties due to FMS. In conclusion with the earlier experiments, design guidelines are derived and furthermore, the gathered information is applied to a simulative approach on FMS with a Mechanistic Model.

An accurate predictive analysis of fiber orientation is crucial for practical injection molded fiber composite applications. Recently, an objective model, iARD-RPR (Improved Anisotropic Rotary Diffusion and Retarding Principal Rate), has been significant to provide anisotropic distribution of fiber orientation, such as the well-known skin-shell-core structure. The micro-computed tomography (micro-CT) scan is state-of-the-art technique for measuring a very high 3D resolution of a specimen’s fiber orientation data. According to the micro-CT experiments and injection molding simulations with the iARD-RPR computation, we investigate changes in fiber orientation distributions for different fiber concentrations in rectangle plate. Comparisons of the fiber orientation predictions with the validated experimental data are also presented herein.

This study investigated the effects of MMT (0.5, 1, 3 wt%) loading on thermo-mechanical, adsorption properties of microcellular injection molded PPgMA nanocomposites. The injection molding process was done by non-foam and microcellular molding. Results showed that the dispersion from TEM pictures, some of MMT are intercalated and some of them are exfoliated structures. This 0.5 wt % loading of MMT had the best tensile strength for solid molding while it is 1.0 wt% loading for microcellular molding on PPgMA material. This is the results of MA grafted PP. Tensile strength is related to the filler dispersion in the matrix. Good dispersion resulted in good tensile strength. It had the highest storage modulus for 0.5 wt% MMT loading PPgMA/MMT nanocomposites from the DMA test results. TGA results showed that thermal degradation can be increased with addition of MMT into matrix. SEM morphology showed that with addition of MMT, cell size decreased and cell density increased. Heavy metal adsorption test showed that MMT can adsorb Pb(II) more efficient than that of neat PPgMA.

Polypropylene single-polymer composites (PP SPCs) are the materials where both the reinforcing phase and the matrix phase are PP. Graphene nanoplatelets (GNPs) have good mechanical properties because of its unique structure. In this study, GNPs were used as one kind of nanofiller to add in PP SPCs to improve its thermal properties and tensile properties. The PP-GNPs SPCs were prepared by film-stacking method. Differential scanning calorimeter experiments (DSC) were executed to determine the hot pressing temperature and investigate the thermal properties. Influences of the GNPs content on the tensile properties of PP SPCs were studied through the tensile tests. The results show that the melting peak temperature and tensile properties increase with the increase of GNPs content.

Polypropylene single-polymer composites (PP SPCs), whose matrix and reinforcement came from identical type of polymers, were fabricated by an approach of applying undercooled polymer melt. The undercooling method could enlarge the processing temperature windows thus realize the fabrication of SPCs without destroy the reinforcement structures. Rheology could be used in the processing of the SPCs, however there is little investigations. This work was done with the aim to investigate the effect of undercooling compaction temperature from 125 oC to 145 oC on rheological properties of PP SPCs by dynamic rheological measurements. The linear viscoelastic range (LVE) was measured for strain sweep. And it was found that complex viscosity of PP SPCs increased as the temperature increased, whereas the storage modulus decreased during frequency sweep. Moreover, the photography of morphology before and after tests revealed a positive correlation between the degree of shrinkage and the compaction temperature. Overall, the effects of temperature on rheological and morphology properties of PP SPCs are strictly dependent upon the molecular structure parameters.

This investigation focuses on the fiber-matrix-interaction of man-made cellulose fibers (RCF) in a PP matrix with an additional MAPP content using an energetic evaluation of the single fiber pull-out test (SFPT). Furthermore glass fibers were characterized for reference purposes. With the SFPT the interfacial shear strength (IFFS) and the critical fiber length (lc) as well as the consumed energy of a fiber pull-out and a fiber rupture were determined. In a following step the resulting values of lc were related to the fiber length distribution in injection molded specimens. It was shown that, based on the longer RCF in the specimen, theoretically more fiber ruptures appear in the RCF composites. But the RCF composites also contain a higher number of long fibers, consuming a higher amount of energy by being pulled out during a composite failure. The length-dependent consumed energy of a fiber pull-out was increased by using MAPP but simultaneously the critical fiber length was significantly reduced.

Semicrystalline plastics often show necking and drawing behavior in tension. In contrast, rubbery materials do not show necking, but instead stretch homogeneously. We examine the behavior of bilayer laminate composites of linear low density polyethylene (LLDPE) and styrene-ethylene/propylene-styrene (SEPS) rubber to test the extent to which the SEPS can modify the necking behavior of the LLDPE. Video recordings of tensile tests on dog-bone shaped samples were analyzed by a Digital Image Correlation (DIC) technique to quantify the degree of non-homogeneity in deformation. The LLDPE showed severe necking with a natural draw ratio exceeding 5. Upon bonding it to a rubber layer, the natural draw ratio reduced significantly. With a sufficiently large SEPS thickness, the neck was almost completely eliminated and the sample reverted to nearly-homogeneous deformation. We present a simple 1D model of the mechanics of the bilayer laminate in which the force within the bilayer is treated as a sum of the force of a Mooney-Rivlin rubber layer and an elastoplastic layer. The model predicts the decrease in natural draw ratio and the elimination of necking as rubber thickness increases, consistent with experiments.

We prepare polypropylene (PP) composites with both pristine halloysite nanotubes (p-HNT) and PP grafted halloysite nanotubes (PP-g-HNT) using two processing techniques, solid-state shear pulverization (SSSP) and melt mixing. We address the role of isolated polymer-filler interaction effects on polymer nanocomposite property enhancement at similar, high levels of filler dispersion. As demonstrated by microscopy and rheology, nanocomposites prepared by SSSP with different fillers have very similar, well-dispersed states, eliminating differences in dispersion as a factor in property enhancements. The well-dispersed PP/PP-g-HNT nanocomposites exhibit a broad range of properties that are superior to those of PP/p-HNT, including tensile strength, PP non-isothermal crystallization onset temperature, and isothermal PP crystallization half-time. However, the Young’s modulus is the same regardless of filler modification. Only superior filler dispersion contributes to Young’s modulus enhancement in nanocomposites.