Materials Bio-PA for
Materials Bio-PA for handheld devices New advanced polymers have enabled handheld device designers greater freedom so they can continue to refresh the look, feel and upgrade performance, while delivering a better environmental footprint, according to Handheld Segment Leader Mark Hazel of DuPont Performance Polymers. Hazel identifies the polymer material as DuPont Zytel ® RS HTN high performance polyamide – a partly renewably sourced specialty polyamide compound made with biobased sebacic acid. Stiffness, strength, low warpage and low moisture pickup combine to help ensure thinner walls for sleek, light designs that improve performance. In handheld electronics applications one of the major characteristics required in a material is its Radio Frequency Interference (RFI) compatibility. If the material picks up moisture, it changes its RFI characteristics and detunes itself. This means that the battery has to supply more power to the antenna and the battery life suffers as a result. Engineers at DuPont have developed enhanced materials, which are less prone to moisture absorption. Handheld electronic devices such as smartphones, laptops, ultrabooks, game controllers and hand held meters evolved over the past years, with larger screens and more powerful electronics. Thus many OEMs steadily reverted to a design where the screen and rear cover act as significant parts of the structure, freeing up much more internal space for the enhanced electronics. Many manufacturers also realised that they could tackle significant sustainability targets by deploying renewably sourced materials, such as Zytel RS HTN, for both structural and aesthetic elements of the phone‘s casing. The high performance polyamide can be used to make thinner, lighter and more durable handheld device housings while making them longer-lasting and easier to produce. From a processing perspective, Zytel HTN grades can also save energy, cost and time thanks to its excellent flow and dimensional stability. A halogen-free, flame-retardant grade is also available for compliance with recycling programs for discarded electronic products. Specific grades are also available that can withstand high-temperature circuit assembly methods, including those using lead-free solder. Aesthetically, both grades (Zytel HTN and Zytel RS HTN) deliver very good surface quality and appearance and are easily coloured. All the materials developed by DuPont for the hand held market are highly stiff and protect the parts from excessive deflection if dropped. Hazel explains: „Screens and circuit boards cannot twist or deform too much so stiffness is vital. We use 55% glass filler to achieve the best stiffness and toughness (only possible in Nylons such as Zytel HTN), but we also have to consider RFI compatibility, colourability and surface finish – it is a fine balancing act.“ DuPont has also developed a repetitive-impact test, which, rather than testing impact test bars to discover the energy to shear, actually tests and measures the number of times a sample can be hit until it breaks This test is much more representative of the use a handheld device will see and demonstrates that Zytel HTN and Zytel RS HTN offer class-leading performance. MT Tensile Strength (MPa) 300% 250% 200% 150% 100% 50% Stiffer PC/ABS-15%talc Zytel RS HTN59G55LWSF PC-GF 40% Zytel HTN 55G55LWSF Zytel HTN FR55G50NHLW 0% 0 5000 10000 15000 20000 25000 Tensile Modulus (MPa) 24 bioplastics MAGAZINE [04/13] Vol. 8
Materials Biobased acrylic acid BASF (Ludwigshafen, Germany), Cargill (Minneapolis, MN, USA) and Novozymes (Copenhagen, Denmark) recently announced the achievement of an important milestone in their joint development of technologies to produce acrylic acid from renewable raw materials by successfully demonstrating the production of 3-hydroxypropionic acid (3-HP) in pilot scale. 3-HP is a renewable-based building block and one possible chemical precursor to acrylic acid. The companies also have successfully established several technologies to dehydrate 3-HP to acrylic acid at lab scale. This step in the process is critical since it is the foundation for production of acrylic acid. In August 2012, BASF, Cargill and Novozymes announced their joint agreement to develop a process for the conversion of renewable raw materials into a 100% biobased acrylic acid. “3-HP is a potential key raw material for the production of bio-based acrylic acid which is a precursor of superabsorbent polymers,” said Teressa Szelest, Senior Vice President Global Hygiene Business at BASF. “We still have a fair amount of work to do before the process is commercially ready, but this is a significant milestone and we are confident we can continue to the next level of scale-up for the entire process in 2014.” Acrylic acid is a high-volume chemical that feeds into a broad range of products. BASF is the world’s largest producer of acrylic acid and has substantial capabilities in its production and downstream processing. BASF plans initially to use the bio-based acrylic acid to manufacture superabsorbent polymers that can soak up large amounts of liquid and are used mainly in baby diapers and other hygiene products. Presently, acrylic acid is produced by the oxidation of propylene derived from the refining of crude oil. The companies’ joint project team combines world-class expertise in biotechnology, renewable feedstock, industrial scale fermentation, and in developing new chemical processes. “Our three companies have assembled highly talented and experienced joint working teams for this project,” said Jack Staloch, Vice President of Biotechnology R&D at Cargill. “They’ve moved with speed and intensity, and have demonstrated great progress toward accomplishing our goals.” “We have reached an important milestone by producing 3-HP in pilot scale,” said Rasmus von Gottberg, Vice President of Corporate Development and Business Creation at Novozymes. “We have shown that it is possible to make this key chemical building block from renewable raw materials in robust industrial conditions. Now the development work will continue towards commercialization.” Superabsorbent polymers derived from bio-based acrylic acid will be a groundbreaking new offer to the market. Diapers made of such superabsorbent polymers could meet the demand of a significant and growing group of consumers in mature markets in particular. They also may allow diaper producers to meet consumer demands, differentiate their products and contribute to their sustainability goals. www.basf.com. www.cargill.com www.novozymes.com (Photo: iStock, Get4Net) bioplastics MAGAZINE [04/13] Vol. 8 25
