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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It has been shown that studying the processing stability of polypropylene using continuous micro-compounding provides comparable results with statistical repeatability to the traditional multiple extrusion approach but with the added advantage of being quicker and requiring less material. Using this approach we have further compared the performance of different stabilizer systems made up of primary- and secondary-antioxidants at different loadings to evaluate the efficacy of stabilizer systems rather than of the various antioxidants themselves.
As many plastic films tend to stick together, making difficult to separate film layers, some mineral additives are used to improve this situation. Specifically, in LLDPE films micronized talc is often used as antiblocking agent. Thanks to the micro-roughness achievable on film surface, talc acts as a spacer between the film layers minimally affecting transparency and other mechanical properties. The presence of talc in the LLDPE film formulation interacts with other additives, creating a unique set of properties that makes talc a very effective additive for film applications. In this paper, talc will be investigated for its intrinsic characteristics in comparison with other known mineral antiblocking additives to evaluate their effect in LLDPE film. A comprehensive evaluation of several properties will be performed to rank each single tested additive for the antiblocking function, considering all the side properties including mineral additive abrasivity and bulk handling It will be also introduced a novel talc antiblocking additive characterized by free-flowing appearance and dust-free behavior, for innovative solutions in talc handling.
Polyolefin materials by itself are not suitable for long-term applications due to their too high sensitivity to oxidation. The major technology step to slow down the oxidation of polyolefins in the solid state are sterically hindered phenols (often referred to as phenolic antioxidants). This principle technology, developed already in the 1970s, enables service lifetimes of polyethylene thick section articles (e.g. pipes) in excess of 50 years. This technology had later-on to be finetune for (drinking) water pipes to avoid the extraction of the phenolic antioxidant during the contact with water and to ensure service life in the presence of free chlorine in drinking water. Particularly polypropylene-random copolymers (PP-R) has been a material of choice for use in the production of plastic pipes for hot and cold water for more than 20 years. Long-term thermal stabilization (LTTS) was traditionally based on phenolic antioxidants and thioesters. The thioester was later dropped, as it had a negative effect on the taste and odor of the water. Nowadays, single phenolic antioxidants or combination thereof are the key components for LTTS. In the drinking water system chlorine dioxide (ClO2) prevents the formation of germ or bacteria, however it is much more aggressive than hypochlorous acid and chloramine and leads to premature failure of polyethylene pipes. The paper presents solutions to significantly to extend service life of PP-R in water extractive applications and improve the stabilization of polyethylene pipes in contact with water containing ClO2.
Additives are widely used to tailor polymer properties like clarity and mechanics, and long-term characteristics like durability for particular applications. Due to the constant emerging of new additives a continuous development of appropriate methods for their analysis is required. While analytical methodologies have been developed concomitant with the use of additives, these do not fulfil the current needs, set by legislation and modern material development. In this sense, the comprehensive separation of additives, including their metabolites, from the polymer is a gap of technology. Drivers behind the need are regulatory issues (REACH) and the efforts towards a circular plastics economy, where the multiple reuse of plastics becomes a rule. As a consequence the quality of recycling technology has to be ensured, and, structure-property relationships for their products need to be mapped. While the questions in the case of Post Industrial Waste are still fairly straightforward, Post Consumer Waste significantly expands the range of analytical challenges. These are, for example, set by the presence of multiple additives in a compositionally non uniform polyolefin matrix. Furthermore, possible contaminations, brought in from the first life cycle, need to be tracked. A newly developed analytical approach will be presented, which in future can become part of the industrial routine portfolio and thus foster the transformation towards a circular plastics economy.
Abstract As polyethylene production has increased and the rotational molding market has expanded, there is a growing demand for improved performance in thermal and ultraviolet light stabilization for end-use applications. These requirements, coupled with the current drivers towards sustainable and environmentally-friendly solutions, present opportunities for additives in polyethylene. In this presentation, we present solutions that enable players throughout the supply chain to produce products that enhance durability, reduce energy cost in production, increase throughput, and accommodate rework and recycle requirements.
Wide range of sterically hindered phenols (primary antioxidants) are used in conjunction with organo-phosphites (secondary antioxidants) for adequate stabilization of Polypropylene and Polyethylene for meeting specific application requirements. These antioxidants inhibit polymer autoxidation throughout the value chain from manufacturing to end use applications and recycling. The guidelines for phosphite selection include % phosphorous, chemical structure, thermal stability, solubility in resin and efficacy. In this presentation we will focus on the quest for robust and high performance stabilization system (lower additive loadings, better color retention, resistance to gas fading etc) for Polypropylene and HDPE for meeting specific performance requirement.
Polymers have become a significant part of our lives, owing to their extended range of applications. The possibilities to achieve more impressive functionalities makes this material promising for the future advancement. One of such application, which is gaining attention, is bacterial control properties imparted to plastics by using suitable additives. A suitable antimicrobial additive plays a crucial role in making plastics safer for us. Further, the presence of microbes may also negatively affect the aesthetics and properties of the product (such as mechanical, electrical and other properties). The bio-film formation may exhibit severe dust pick-up and may also impart foul odor in the plastic articles. The traditional solutions typically include metal-based compounds, nanoparticles, toxic element containing compounds or other categories, wherein the biocide properties can be attained. The trend of bio-based and safer additives poses the demand for more benign products. FinaGuard AM is well-suited for such requirements, as it is a unique naturally derived antibacterial additive, free from metal/nanoparticles offering excellent performance in Gram (-) & Gram (+) bacteria. It brings forth manifold benefits such as effective antimicrobial performance, sustainability as well as safety during handling & service life. FinaGuard AM is an internal additive, therefore, can be incorporated in plastics via a masterbatch route. It has been tested by JIS Z 2801: 2010 in polyolefins and PVC. The potential application spectrum for FinaGuard AM is evidently wide, for instance – medical apparatus, domestic products (e.g. kitchen utensils, flooring, bath mats, shower curtains), fabrics/clothing, furniture (e.g. chair handle, table tops, door handles) and construction materials/interiors (e.g. tiles, wallpaper, flooring).
Most plastic additives are manufactured today from fossil resources through established chemical processes. Additives from natural resources (“Bioadditives”) are known as well and representatives of several additive classes have been used for many years. However, the need for bioadditives is increasing to replace traditional fossil based additives. Moreover the growth of biopolymers enforces the requests for natural based additives to offer fully biobased systems to the market and to support circular economy. Within the extensive variety of additives biobased products are found in the class of plasticizers, antioxidants, lubricants, antifogging agents and clarifiers. Plasticizers from different natural resources (citric acid esters, succinic acid esters, isosorbide esters) have captured a significant market share. Lubricants such as fatty acid esters and their salts are well-known standard products. On the other side several large additive areas such as flame retardants, light stabilizers or impact modifiers are still not represented. Phenolic structures are omnipresent in nature and can be isolated from many plants [1]. Vitamin E (“Tocopherol”) is the classical example of a naturally based antioxidant providing excellent processing stability to polyolefins [2]. However, secondary antioxidants such as phosphites are not found in nature. To benefit from the well-known synergism of primary and secondary antioxidants in polymer stabilization a natural based alternative to phosphites is mandatory. The presentation will give an overview on bioadditives for plastics and will show new stabilizer concepts fully based on natural resources.
The most recent developments in grafting technology for polyolefins have been applied on an industrial scale to help solve challenges in performance and processing of these ubiquitous materials. Through the use of solid phase grafting, the unique properties of each polymer can be retained while reducing undesirable side reactions. This approach has been applied to a wide range of polyolefins to address key performance needs; specifically the creation of Polyolefin Alloys. These grafted side chains of LDPE / PS, LDPE / SAN, PP / SAN modify the properties of the bulk polymer. This paper will illustrate the resulting properties when incorporated into blends of other polyolefins, ABS, PLA, and PC blends. The use of solid phase grafting technology also allows for the facile addition of MAH to a range of polyolefin backbones. The effectiveness of the method results in polyolefins which retain a high MFI, a high percent of MAH functionality and low volatility / residual MAH levels. HDPE, PP, POE, EBA, LLDPE grafted with MAH have all been successfully prepared and tested. These novel graft polyolefins exhibit excellent performance in a wide range of thermoplastic compounds and composites. In addition, a new approach to incorporating low MW functional additives into the polyolefin melt has been developed. Porous granules which can adsorb up to 80% by weight are now available in a variety of polymers including LLDPE, PP and EVA. The porous polyolefin carrier absorbs the liquid additive and allows the resulting dry granule to be metered into the compound as with any other solid additive. The result is a much better match of melt viscosity with more thorough mixing and incorporation into the compound. A wide range of liquid additives and additive blends have been successfully incorporated into polyolefin compounds including; Crosslinking of PE through the Monosil process; Vinyl Silane / peroxide, Addition of Boron based HFFR, Addition of MAH, Silicone oils and gums Antistats, anti-fog, slip aides and other low MW additives.
The most recent developments in grafting technology for polyolefins have been applied on an industrial scale to help solve challenges in performance and processing of these ubiquitous materials. Through the use of solid phase grafting, the unique properties of each polymer can be retained while reducing undesirable side reactions. This approach has been applied to a wide range of polyolefins to address key performance needs; specifically the creation of Polyolefin Alloys. These grafted side chains of LDPE / PS, LDPE / SAN, PP / SAN modify the properties of the bulk polymer. This paper will illustrate the resulting properties when incorporated into blends of other polyolefins, ABS, PLA, and PC blends. The use of solid phase grafting technology also allows for the facile addition of MAH to a range of polyolefin backbones. The effectiveness of the method results in polyolefins which retain a high MFI, a high percent of MAH functionality and low volatility / residual MAH levels. HDPE, PP, POE, EBA, LLDPE grafted with MAH have all been successfully prepared and tested. These novel graft polyolefins exhibit excellent performance in a wide range of thermoplastic compounds and composites. In addition, a new approach to incorporating low MW functional additives into the polyolefin melt has been developed. Porous granules which can adsorb up to 80% by weight are now available in a variety of polymers including LLDPE, PP and EVA. The porous polyolefin carrier absorbs the liquid additive and allows the resulting dry granule to be metered into the compound as with any other solid additive. The result is a much better match of melt viscosity with more thorough mixing and incorporation into the compound. A wide range of liquid additives and additive blends have been successfully incorporated into polyolefin compounds including; Crosslinking of PE through the Monosil process; Vinyl Silane / peroxide, Addition of Boron based HFFR, Addition of MAH, Silicone oils and gums Antistats, anti-fog, slip aides and other low MW additives.
Plastics are a major focus of sustainability efforts around the world, due to their ubiquity and the volume of waste they generate. Many companies are proactively applying environmental goals throughout the plastics lifecycle, from R&D through application development, manufacturing and disposal. While they may not produce plastics, additive manufacturers nonetheless are playing an important role in reducing environmental impacts and advancing environmental objectives. Examples include promoting the increased use of recycled plastic content by formulating additives such as performance modifiers specifically designed to optimize recycled content. Or by replacing or removing ingredients which could negatively affect recycling streams or cause concern with regards to migration or extraction. Further, additive manufacturers are addressing the challenge of excessive packaging by developing products that maintain desirable properties, such as barrier performance, while using thinner walls or film gauges. Used in food packaging, innovative additives can avoid the need for preservatives in the food itself to support the Clean Label trend, while extending shelf life to reduce waste. This paper will describe how Milliken is adding sustainability considerations to its goals for the research and development of additives for virgin and recycled resins, as well as expanding its portfolio with products specifically tailored to meeting environmental goals across the plastics lifecycle.
Circular economy will change our way to design plastic products to provide greater durability, reuse and high-quality recycling. The European Union will considerably reduce landfill, introduce economic incentives to put greener products on the market and drive investments and innovation to circular solutions. In addition to improve design to make plastic products easier to recycle, collection and sorting will be expanded and viable markets for recycled and renewable plastics will be created [1]. Recycling of plastics will grow and the quality of recyclates has to be improved to replace pristine polymers. Additives such as stabilizers, repair additives, compatibilizers and odor neutralizing agents play an important role to enhance and to maintain the quality of recyclates [2]. Stabilizers for recyclates fulfil the same function as in virgin material namely to protect the polymer from oxidative degradation during processing and to maintain the properties during use. Consumed stabilizers of the first application have to be replaced at least and/or adjusted to the requirements of the second application. For example a recyclate from a short-time packaging application is not sufficiently stabilized for a long-term service life. Moreover, there are structural differences between virgin and recycled polymers. Recycled plastics show usually predamage through oxidation from the first service life e.g. an increased carbonyl and carboxyl group content versus virgin material is found in polyolefins. Moreover the oxidized molecular structures act as initiator sites and prodegradants accelerating recyclate degradation during processing and use [3, 4]. Furthermore, recycled plastics are often mixtures from different manufacturers and formulations with various additives and may contain more or less impurities. Specific recyclate stabilizers were developed in the past, however mainly as a variation of standard virgin stabilizer systems. Selected combinations of phenolic antioxidants, phosphites and antiacids in optimized ratio prove that the best cost/performance stabilizer combination for recyclates is different from the one for virgin material. Now a new generation of improved recyclate stabilizer systems combines antioxidants and selected alditols [5]. These systems may act in several ways: interaction with carbonyl groups, hydroperoxide decomposition and metal deactivation, thus addressing the potential weaknesses of recycled plastics. The newly developed stabilizer systems for polyolefins show excellent processing stability of PP and PE recyclates and outperform alternative stabilizers in long-term thermal stability. For commercialization of the technology an industrial partnership is established.
The global production of plastic reached 350 million tons in 2017, of which a large part ends up in landfill and/or incineration. Further, 1.5 to 4% of the global production of plastics ends up in marine littering every year and plastic stand for 80% of the marine littering (1). EU has set ambitious goals to reduce the littering from plastic packaging with an aim to recycle 50% plastic packaging by 2025 and 55% by 20302. Reaching these goals requires larges changes within the whole plastic industry (2) and new innovative solutions in mechanical recycling. Today, the stabilization additive packages are often not designed for recycling. When plastics are recycled the polymer will experience multiple processing steps which means polymer degradation unless actions are taken to secure enhanced stabilization. This talk will demonstrate the effect on polymer properties during four recycling steps without extra stabilization, and with multiple additions of antioxidants in the recycling process. The effects of the most used “traditional” antioxidants standing for the largest antioxidant consumption - AO1010, AO1076 and P168 - are demonstrated (3). The study demonstrates the effects on polymer properties in the two mentioned scenarios and identifies gaps-to-close related to use of traditional additives systems in mechanical recycling. For example, how much additives are needed to keep polymer properties intact in recycling and what unexpected properties are observed by accumulation of these additives and their by-products. 1 Jambeck et al. Plastic waste inputs from land into the ocean. Science (2015). 2 EuropeanCommission. A European strategy for plastics in a circular economy. 3 Maier, R. D. & Schiller, M. Handbuch Kunststoff-Additive. (2016).
Current discussions about the use plastics and the waste generated have generated great interest in plastics recycling. While this question is relatively easy to answer for monomaterials, for multilayer or composite materials there is always the question if this can work. On the other hand, to produce high quality flexible packaging, there is the need for multilayer films to protect the packed food and increase the shelf life. To have a closer look at the recyclability for such multilayer films, we wanted to take a closer look at a simple LDPE-PA6-material to see how the materials properties of this mixture can be improved. Therefore, the aim of this work was to compare the effects of compatibilisation with a pre-fabricated additive and the in-situ generation of a similar additive in the melt for LDPE-PA6-blends and to investigate the effect of mixing protocol (i.e. compounding vs. dry-blending) of the pre-fabricated additive on the resulting properties of reprocessed LDPE-PA6 films. We found, that it is possible to compatibilize LDPE-PA6-blends via the addition of maleic anhydride based compatibilizers, regardless of fabrication approach. This effect can be seen from the morphology of the samples as well as from mechanical properties. Also, the reprocessing of films from LDPE and PA6 with reasonable properties is possible when adding a compatibilizer. The best, i.e. the most balanced properties can be found when the compatibilizer is melt compounded, as this gives the best distribution. These results show that it is possible to reuse multilayer materials when considering the blend components and properly selecting a compatibilizer.
Polyethylene and polypropylene are two of the most easily recycled polymers. Recycling polyolefins can result in downcycling to simple functional polymers, true recycling for reuse in the intended application, or upcycling of the polymer into higher quality products. To take advantage of the available feedstock, and improve its utilization, stabilizers are can be added to allow the polymer to retain its original physical properties. A variety of customer based case studies on recycling and upcycling will be covered showing how additives allow for improvements in the recycle stream.
Circular economy and plastics recycling require a Polyolefin stabilization that protects the polymer during the whole cycle in the recycling process. AddWorks LXR 568, Hostanox O310 and Hycite 713 are high performance additives that protects the polymer during processing and heat exposure as well as during the washing step. Antioxidant solutions as AddWorks PKG 906 circle helps the converter and recycler to provide heat and process stability and replenish antioxidants that had been consumed during the recycling process.
The application development labs of SI Group recently invented a highly innovative technology that enables significant reduction in color of discolored polyolefins in industrial or post-consumer recycled streams. This very effective bleach-out phenomena takes place in the polymer melt in a processing extruder upon addition of a new additive system that is a subject to this presentation. The new system is composed of solid-state components and can be fabricated in a powdery form or as a non dusting formulated one-pack. The system does not change the taste and oder properties of polymers and is safe from both the manufacturing and consumer perspective.
In this paper, we demonstrate how a small amount of nanofibrils can enhance the toughness, stiffness, and transparency of polyolefins. We have studied two different kinds of toughening rubbery nanofibrils and stiffening hard nanofibrils depending on the kind of the material used for the nanofibrils, and we have observed that the properties of the nanofibril composites with these fibers were very different. It was observed that the rubber nanofibrils with ~200 nm diameter and an L/D ratio over 200 well dispersed in the PO matrix exhibited numerous outstanding properties, such as elasticity, ductility, toughness, and impact strength. It is commonly well-known that 15-25% rubber content must be compounded into the polymer matrix, to induce brittle-to-ductile transition. But with nanofibril rubbers, only 1% was needed to achieve the brittle-to-ductile transition. These results indicate that the dispersed rubber nanofibrils are much more effective than the conventional spherical rubbery phases in toughening of polyolefins. This has another significant implication that the ductility can be improved without any sacrifice to the stiffness, unlike the case of using a large amount of rubber over 15%. In other words, the toughening of polyolefins can be achieved with less than 1% nanofibril rubber without losing the stiffness. The increased stiffness with added nanofibrils was also studied. When PET or PBT nanofibrils were added in the PO matrix, the nanofibril composites exhibited a much higher stiffness. Unlike the case of using a brittle matrix such as PS or PLA, the increase in the ductility-related properties was marginal in the relatively ductile matrix such as PP or PE. The transparency change of PO materials with included nanofibrils was also studied. Like in the case of Sorbitol, the added nanofibrils decreased the crystal size significantly, to make the PO materials more transparent. But when the nanofiber content was large, then the transparency was decreased because of the large number of nanofibrils. As the nanofibril content decreased, the transparency was significantly improved.
In this paper, we demonstrate how a small amount of nanofibrils can enhance the toughness, stiffness, and transparency of polyolefins. We have studied two different kinds of toughening rubbery nanofibrils and stiffening hard nanofibrils depending on the kind of the material used for the nanofibrils, and we have observed that the properties of the nanofibril composites with these fibers were very different. It was observed that the rubber nanofibrils with ~200 nm diameter and an L/D ratio over 200 well dispersed in the PO matrix exhibited numerous outstanding properties, such as elasticity, ductility, toughness, and impact strength. It is commonly well-known that 15-25% rubber content must be compounded into the polymer matrix, to induce brittle-to-ductile transition. But with nanofibril rubbers, only 1% was needed to achieve the brittle-to-ductile transition. These results indicate that the dispersed rubber nanofibrils are much more effective than the conventional spherical rubbery phases in toughening of polyolefins. This has another significant implication that the ductility can be improved without any sacrifice to the stiffness, unlike the case of using a large amount of rubber over 15%. In other words, the toughening of polyolefins can be achieved with less than 1% nanofibril rubber without losing the stiffness. The increased stiffness with added nanofibrils was also studied. When PET or PBT nanofibrils were added in the PO matrix, the nanofibril composites exhibited a much higher stiffness. Unlike the case of using a brittle matrix such as PS or PLA, the increase in the ductility-related properties was marginal in the relatively ductile matrix such as PP or PE. The transparency change of PO materials with included nanofibrils was also studied. Like in the case of Sorbitol, the added nanofibrils decreased the crystal size significantly, to make the PO materials more transparent. But when the nanofiber content was large, then the transparency was decreased because of the large number of nanofibrils. As the nanofibril content decreased, the transparency was significantly improved.
For many decades’ metallic oxides, metallic stearates have been used to scavenge acids from the 1st – 4th generation TiCl4 catalysts spanning 1955-1995. Metallic oxides and stearates form Lewis Acids which reduce antioxidant efficiency resulting in polymer degradation. New line of Stabiace hydrotalcites improve oxidation stability of polypropylene proven by OIT, MFR and tensile properties. Mitsui’s trade secret ZR Series provides same performance of Stabiace HT with addition of much less color and further reduction in PP oxidation proven by FTIR. Three polypropylene take-a ways: 1. Quality: New Stabiace HT improves the oxidation stability and physical properties. 2. Quality + Performance: Mitsui ZR Series no yellow color and 50-60% increase in antioxidant retention, increased OIT and up to 80 % less polyolefin degradation per FTIR analysis from 1-5 extruder passes at 250c. 3. Recycle and sustainability: Because the PP has much less multi-pass extruder oxidation; quality, recyclability, sustainability, odor and VOC reduction may be improved.
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