Caps & closures | packaging
assist with track and tracing, they only really help to validate the origin of a bottle. Drink manufacturers may need to deploy several tactics simultaneously to prevent brand value being diluted, including tamper evident caps, barcoded labels and batch codes, and even chemical markers. Similar approaches to cap innovation are also being
deployed by the soft drinks and mineral water sector, including widespread adoption of secure closures, tamper evidence bands and push buttons to reveal when a seal has been broken. “For trade moulders that are producing beverage caps and closures by the millions, cost effectiveness is vital,” adds Heap. “It therefore makes good economic sense to build a complete moulding system to take care of all the anticipated applications, rather than trying to adapt existing equipment. Due to the increased precision involved in moulding caps, many manufacturers are prepared to invest in new high-perfor- mance plant and switch from hydraulic and hybrid to all-electric injection moulding systems.” At the Drinktec exhibition in Munich in September,
Netstal is highlighting a 38mm single piece closure application for the Prelactia milk bottle. The company says that there will be an Industry 4.0 showcase, with an injection moulding machine receiving data packages from Intravis CapWatcher. The company says that the system offers good productivity, quality and low unit costs. It will be produced on an Elion injection moulding machine using a z-moulds tool with z-slides tool technology to provide tamper-evident closures. The mould has 32 cavities and the 2.8g HDPE closure is manufactured in a cycle time of 4.0s, giving a production rate of 28,800 closures/hour. Prelactia bottles comprise a double-layer preform design featuring a grey interior wall that is impervious to light and a white outer skin. Both are made entirely of PET, meaning the bottles are fully recyclable. UPM Conveyors has developed a range of conveyors
incorporating high air flow fans mounted over a water cooled heat exchanger. The company says that the conveyor is to cater for multi impression closure mould- ing where typically 120 caps can be moulded on a 10s cycle. In this application it is imperative to cool them down quickly to avoid deflection in the collection bin, as well as further reduce the cycle time. Cold air is blown onto the closures to reduce the temperature from typically 70°C to 20°C and a variable speed control is available as standard to regulate the time product remains under the air flow. In addition, UPM says that it has fitted air ionisers at the discharge area to remove static, with the result that one major closure manufac- turer has seen a production increase of 38% with a payback time of only three months.
www.injectionworld.com
Above: Many cap producers are now investing in all-electric injection moulding systems, such as this IntElect Smart from Sumitomo (SHI) Demag, to manufacture the plastic components found within intricate anti-tamper caps
Greener caps According to polyolefins supplier Braskem, the main market trends in caps and closures include inviolability systems and functionality. In addition, there are environmental issues, such as mono-materials for one-piece solutions capable of providing easier recycling, and the use of post-consumer recycled (PCR) material and material from renewable sources for producing new resin grades. Consumer factors such as healthier lifestyles and an ageing population are also important in cap and closure design, says the company. An additional trend is higher performance resins, such as bimodal, to allow lighter weight caps. Braskem’s focus in caps includes recyclability,
lightweighting, easier opening and multifunctional caps. In addition, the industry is looking for drop-in solutions that reduce the carbon footprint of caps and closures, such as the polyethylene Braskem makes using sugarcane ethanol as feedstock and marketed in its “I’m Green” inititative. The company is also developing grades that can be used in intelligent packaging, includ- ing caps and closures, which can indicate if the product’s contents are still fit for consumption. These interactive polymers are able to identify changes in the external or internal environment and provide a colour change in the packaging. Working with a partner, Braskem has also converted PCR from disposable cups to produce a polypropylene that is being used in caps and closures for the home and personal care market. Specifically HDPE grade GE7252XP has been devel-
oped for use in injection and compression mould closures for applications in carbonated soft drinks and sparkling water. The resin is claimed to have good environmental stress cracking resistance to allow lightweighting. It can also be produced as part of Braskem’s “I’m Green” portfolio of polyethylenes for injection moulding. The company is also developing PCR resins in partnership
July/August 2017 | INJECTION WORLD 47
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