By Ms. Anju Bharti
A tin can/steel can is a container for the distribution or storage of goods, composed of thin metal, an alloy of approximately 55 percent steel and 45 percent aluminium. Aluminium is a widely available, affordable, lightweight metal that is easy to shape. It is far more cost-effective to recycle aluminium than to extract it from its ores.
Many cans require opening by cutting the ‘end’ open; others have removable covers. A beverage can is a metal container designed to hold a fixed portion of liquid such as carbonated soft drinks, alcoholic beverages, fruit juices, teas, herbal teas, energy drinks, etc. Beverage cans are made of aluminium (75% of worldwide production) (Brody, 1997) or tin-plated steel (25% worldwide production). Worldwide production for all beverage cans is approximately 370 billion cans per year worldwide.
The key development for storing beverages in cans was the interior liner made of plastic or a waxy substance that helped to keep the product’s flavour from being ruined by a chemical reaction with the metal. The early cans did not have a ‘pull tab’ instead they had a ‘crown cork’. The Wales, from the 18th century until the early 20th century dominated world tinplate production peaking in the early 1890s when 80 percent of the world’s tinplate was produced there.
The canned beverages were factory-sealed and required a special opener tool in order to consume the contents. These cans were typically formed as cylinders with a flat top and bottom. They required a can piercer known to be a ‘church key’. It latched onto the top rim for leverage and lifting the handle would force the sharp tip through the top of the can, cutting a triangular hole. Secondly, a smaller hole was usually punched at the opposite side of the top to admit air while pouring, allowing the liquid to flow freely.
In the mid-1930s, some cans were developed with caps so that they could be opened and poured more like a bottle. These were called ‘cone tops’ as their tops had a conical taper up to the smaller diameter of the cap. Cone top cans were sealed by the same crimped caps that were put on bottles, and could be opened with the same bottle-opener tool.
The popularity of canned beverages was quite slow as the metallic taste was difficult to overcome with the interior liner not perfected, especially with more acidic sodas. Steel cans had two advantages over glass bottles. First for the distributors, flat-top cans were more compact for transportation and storage and weighed less than bottles. Secondly, for consumers, they did not require the deposit typically paid for bottles, as they were discarded after use. Glass-bottle deposits were reimbursed when consumers took the empties back to the store. For the first time, the soft drinks to be sold in all-aluminium cans were R.C. Cola and Diet-Rite Cola, both made by the Royal Crown Cola company, in 1964.
Many consumers found that a drink from a can had a different taste compared to drinks from a fountain or glass bottle. Although an aluminium can had an internal coating to prevent the contents from directly contacting the aluminium, the internal coating occasionally failed, and the contents may then create a hole, causing the can to leak.
Pull-tabs were a common form of litter. Some users dropped the aluminium tab into the can and occasionally swallowed the sharp-edged tab by accident. Stay tabs (also called colon tabs) were invented by Daniel F. Cudzik of Reynolds Metals in Richmond, Virginia in 1975 (Hanlon, 1998) partly to prevent the injuries caused by removable tabs. Stay tabs almost completely replaced pull-tabs in many parts of the world by the early 1980s, though pull-tabs were still common in places such as China and the Middle East.
Another unsuccessful variation among opener was the press-button can, which featured two pre-cut buttons, one large, one small, in the top of the can, sealed with a plastic membrane. These buttons were held closed by the outward pressure of the carbonated beverage. To open the can, the consumer would press both buttons into the body of the can, thus opening one through which to drink the beverage, the other to provide sufficient air to allow the contents to flow more easily. The buttons would remain attached to the can, alleviating the earlier issues with pull-tab ingestion.
The problem that current design had was that the top edge of the can may collect dust or dirt in transit, if the can is not packaged in a completely sealed box. Some marketers have experimented with putting a separate foil lid on can tops, and shipping cans in cardboard 12 or 24 pack cases.
Many consumers found the taste of a drink from a can to be different from fountain drinks and those from plastic or glass bottles. Some people believed that aluminium leaching into the fluid contained inside can be dangerous to the drinker’s health. The exact role (if any) of aluminium in Alzheimer’s disease is still being researched and debated, though the scientific consensus is that aluminium plays no role in development of the disease.
Technology Upgradation/Current characteristics
Most beverage cans have a slightly tapered top and bottom. The metal on the lid of the can were significantly thicker than the metal on the sides. It meant that a great deal of raw materials could be saved by decreasing the diameter of the lid, without significantly decreasing the structural integrity or capacity of the can.
The most recent advance in can design has been the ‘wide mouth’ can: the opening was initially enlarged in the late 1990s by Mountain Dew. In 2000, Crown Holdings, Inc. introduced an improvement in beverage end technology, named SuperEnd. The geometry reduces the aluminium content by 10 percent and creates a ‘billboard’ area, usable for brand logos and special messages. Cans come in varying heights and diameters to encompass the range of capacities currently in use, but the diameters are usually one of the two standard sizes, 65 mm or 52 mm.
Modern cans are generally produced through a mechanical cold forming process that starts with punching a flat blank from very stiff cold-rolled sheet. This sheet is typically alloy 3104-H19 or 3004-H19, which is aluminium with about 1 percent manganese and 1 percent magnesium to give it strength and formability. The flat blank is first formed into a cup about 3 inches in diameter. This cup is then pushed through a different forming process called ‘ironing,’ which forms the can. The bottom of the can is also shaped at this time. The malleable metal deforms into the shape of an open-top can. With the sophisticated technology of the dies and forming machines, the side of the can is significantly thinner than either the top and bottom areas, where stiffness is required. One can-making production line can turn out up to 2400 cans per minute.
In India, high growth in segments such as juice and healthy beverages is showing a positive effect on the beverage cans industry. Presently, beverages packed in cans cover only around 5 percent of the country’s $11 billion packaged beverage industry. However, the overall packaged beverage industry in India has been growing at 5-6 percent year-on-year basis.
In spite of the growth in packaging spend, tinplate accounts for only a small percentage of the total packaging medium (Bose, 2008). The threat for the tinplate manufacturers may be through packaging from an alternative packaging medium such as tetra packs, polyethylene, etc.
Beverage tin/steel cans chill faster and stay colder longer than any other beverage container. They are the world’s most recycled drink container. They make storage quite easier with its unique stacking ability. Aluminium cans are lightweight, strong and economical; it’s no wonder that it is today’s preferred package. It can boost up the unparalleled environmentally friendly convenience of delivering the premier consumer experience.
The writer is Assistant Professor, Maharaja Agrasen Institute of Management Studies, Rohini, New Delhi