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.
Demand for increased recycled content in various applications has driven innovation toward incremental step change in recycled material quality. In pursuit of increasing recycled content usage in extrusion blow molding applications, considerations must be made for the preservation of mechanical properties via the prevention of thermal and oxidative degradation during both the recycling and molding processes. In order to understand the importance of timely implementation of solutions like stabilizer blends, a set of experiments was run on extrusion blow molded articles to illustrate the rate of performance decay that occurs between the recycler and the molder. This analysis proposes pathways to improve upon current recycled content utilization while simultaneously improving end-use properties.
In this work, digital image correlation was performed during compression testing of twodifferent flexible polyurethane foams to obtain full-field strain maps and understand the non-uniformdeformation the foams exhibit. In addition, X-ray micro-tomographywas performed on the foam samples at different locations through the thickness to obtain micro-tomographs of the foams’ microstructures. Measurements and statistical analysis from these micro-tomographs made it possible to quantify the cell size distribution and their variation through the thickness, as well as identify differences in the microstructures of different foams.It was found that observations from compression tests with digital image correlation are in good agreement with observations from X-ray micro-tomography analysis.
The use of foamed polymeric precursors for blow-molding and thermoforming applications is seeing increased use in the world of application development across a wide range of segments such as automotive, appliances, and packaging. Foam blow molding holds great potential for further enhancing lightweight solutions for complex hollow structures, while adding the potential of single-material solutions offering multi-functionality, e.g., thermo-acoustic isolation or damping. Unlike in the case of foam injection-molding, fundamental processing-structure-property interrelationships are not widely researched in the area of foam blow-molding. Modelling, simulations, and predictive engineering of foam blow molding processing are still in their infancy. Any simulation framework for this purpose needs to address the complex interplay between the matrix rheology, foam morphology and morphology evolution, and the resulting processability and thermo-rheological properties of the foamed product. Here, we report a preliminary simulation framework for foam blow molding, demonstrated in the context of foam extrusion blow molding. The framework addresses several important material and processing considerations. These include: (1) the initial foam morphology; (2) the nonlinear viscoelastic characteristics of the foamed melt; (3) the derivation of constitutive parameters for the foam – arriving at a homogenized representation of the foam rheological characteristics; (4) the implementation of blow-molding simulations using these parameters in a commercially available simulation software; and (5) finally correlating the local strains in the blow molded part to its morphology.
The development of a high stiffness Polypropylene (PP) foam for use within the rotational moulding industry has been investigated by Matrix Polymers. The scope is to offer a stiffer and more advanced alternative to the current Polyethylene (PE) foams which are on the market. Matrix Polymers want to push the boundaries of current products and combine new technologies to produce a new material. Differing compositions of CBA (chemical blowing agents), various dry blends and compounds have been trialed alongside experiments into the CBA reaction time and expansion ratios. The availability of K-kord temperature logging equipment has been utilized alongside JUST RITE temperature labels, static oven machines and a rotational Ferry machine to develop the new material. All of the above has furthered understanding into the astonishing potential of this new material. Offering this product to the rotational moulding industry would be greatly beneficial to rotational moulders from around the world in a variety of applications, we understand the limits of rotational moulding are the lack of suitable polymers. This is something that Matrix continues to challenge.
In the plastic industry, the modification of polymers with glass or carbon fibers is common to improve the product quality and properties. Particularly, the twin screw extruder is frequently-used for continuous compounding, preparation and processing of polymers. The steadily growing demand for fiber-reinforced thermoplastics and the high cost of the carbon fibers are the motivation for recycling. Furthermore, new laws (e.g. EU Waste Framework Directive and End-of-Life Vehicle Regulation) demand the recycling of the remains and the waste of the carbon fiber production.
Extrusion blow moulding enables the cost-effective production of plastic hollow bodies with complex geometries and different volumes. The majority of the components are used as packaging articles for the consumer goods- and food industries or as technical components, e.g. in the automotive and chemical industries. Extrusion blow moulded products are often failing at the weld line. The quality of joint depends mainly on the welding temperature. In order to improve this critical area, the IKV is investigating the use of variothermal temperature control of the blow mould. This brings the advantage of being able to locally increase the temperature of the blow mould. By using this temperature control concept, the results show a significant improvement in the quality of the weld line.
This paper presents the processing methods for producing functionally graded rapid rotational foam molded foam composites with supercritical CO2. The cell density of the foamed core is deliberately varied across the length of the part by gradually increasing the talc content from 1 wt% to 3 wt% or by increasing the chemical blowing agent content from 0.5 wt% to 2 wt%. The foamed core of the composite is produced with foaming grade LDPE. The cellular morphology is characterized by its foam density, average cell size, and cell density across the length of the part. A scanning electron microscope (SEM) was used in the characterization process at 37X magnification along with a digital microscope at 30X magnification. The analytical characterization of the foam revealed, LDPE foamed core processing is more suitable when the chemical blowing agent (CBA) is combined with the physical blowing agent (PBA) rather than just utilizing talc with PBA. The cell density within the water-cooled LDPE foam was 1.4e6 cells/cm3 with an average cell size of 137 um. These results demonstrate the capabilities of a new experiment setup designed to combine PBA foam extrusion and RRFM technology.
As cars are manufactured to be on the road, moulding machines are built to run. Not to sit idle on the production floor. But this happens. Moulds changes are necessary to make parts of different sizes and shapes. This means mould set-up time is crucial to the production. Are we able to reduce the set-up time? Surely, we can by changing the mould quicker.
Blow moulders are whispering these days: "Staying ahead of the competition is the key" or "Growing quietly behind the scenes". Are we ready to take the plunge? Psst …
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ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
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