Packaging Technology and Engineering. Dipak Kumar Sarker

1.1c shows a very old cork‐topped bottle and a Victorian–Edwardian steel box for pills, which are practically never seen in the modern era, except for marketing promotions. Figure 1.1 shows a range of mid‐twentieth century, Edwardian, Victorian, and earlier packaging materials used for medicines. The containers cover green chromium glass, iron oxide amber glass, flint glass, and other common forms seen more routinely today, such as paperboard cartons and aluminium closures. The ‘earthenware’ pottery vessel used in the past for medicine, milk, beer, and oil is rarely used in contemporary society but does find a place in speciality products as a marketing tool used to infer tradition and antiquity. Looking carefully at the range of packaging and comparing it with that seen customarily in pharmacies, artisanal, ‘24 hour’, and mini‐mart shops and supermarkets used mostly today there is a stark contrast and difference in Figure 1.1 by virtue of the absence of plastic packaging in the period before 1950 [1].

Figure 1.1 Packaging of the past.

      1.1.2 The Origins of Commercial Packaging

Andreas Bernhardt began wrapping products in paper and waxed paper for water retention stamped with his name and identification in Germany in 1551. Packaging uses and requirements have changed a lot in the modern era and most spectacularly over the last 150 or so years of purpose‐crafted commercial containment. The diversity of past packaging can be seen in Figure 1.1, with examples of flint, amber, green, and blue glass pharmaceutical sample bottles and a range of aluminium cans, paper, card, and pottery primary and secondary packaging. Some of the samples in Figure 1.1 date from the 1960s and 1970s but others date back to the Victorian and Edwardian periods (1870s–1900s). The sometimes perceived as ‘modern‐era’ plastics industry actually started with John Wesley Hyatt, who invented modified cellulose in 1869, and, Leo Hendrik Baekeland, who invented resinous early plastic in 1907 in the USA. Other product examples include the ubiquitous tobacco snuff box (Mander Brothers) of the 1800s, the Beechams pills carton (UK) of the Victorian era in the 1840s, and the Lyons loose tea can (Ireland) and Laymon's aspirin tin (USA) of the Edwardian era in the 1900s. The more familiar forms of plastic containment that first appeared in the 1950s–1970s include the detergent and – the now infamous – mass‐produced carbonated drinks polyethylene terephthalate (PET) bottle. The tin can means of excluding air, light, and water for tea leaves is still used by many companies such as Jin Jun Mei (China), Whittard (UK), Tafelgut (Germany), and Twinings (UK), as part of a value‐adding marketing tool and for protection of delicate flavours and volatile oils. The sea‐change position of the use of tin‐plated steel (tinplate) and the tin can as a standard form of packaging will be discussed in Chapter 3.

      1.1.3 Closures, Films, and Plastics

Rubber used in sealings and liddings became a mainstay of commercial packaging when, in 1849, Charles Goodyear and Thomas Hancock developed a method that destroyed the ‘tacky–sticky’ property of the material and added extra elasticity to natural rubber. In 1851 hard rubber, often referred to as ebonite, became commercially available in the Western world. A completely new revolutionary form of packaging was created in the invention of plastic. The innovative original artificial plastic was created by Alexander Parker in 1838 and was displayed at the Grand International Fair in London in 1862. This ‘parkesin’ rigid ‘resin’ was thought to be able to replace natural materials such as hardwoods and ivory. In 1892 William Painter patented the still ubiquitously used ‘crown cap’ closure (see Figure 3.3c) for bottles shaped from glass [1], which kept air (containing degrading oxygen) out and product flavours locked in. Also, in 1870 Hyatt took out a patent for ‘celluloid’ produced from cellulose in highly controlled conditions, under high pressure and temperatures. This created a polymer with low nitrate content for many different types of product wrappings. This discovery is now thought of as the first commercialised plastic and remained the only ‘plastic’ until 1907, when Baekeland produced ‘Bakelite’ (also spelt as Baekelite). Bakelite was universally used until the 1970s but was replaced by a new wave of plastics. A more exact understanding of plastics arose in 1920, when Hermann Staudinger's revolutionary idea was extolled and the notion of a plastic as a physical property rather than a chemical class came into fruition. All plastics, rubber, and cellulose are polymers or macromolecules but notably some do not show significant plasticity or deformability without brittle rupture. Staudinger's pioneering work concerning ‘polymer science’ was awarded the Nobel Prize in 1953.

      1.1.4 Major Types of Packaging

      Plastic packaging had begun to be used widely across the globe after the 1950s and this has led to the present ‘mountains’ of undegraded waste that are still added to. Polyvinylidene chloride, or Saran®, was first used as a moisture barrier in 1946. In 1960 the two‐piece drawn and wall‐ironed (DWI) can was developed and in 1967 the ring‐pull opening was invented. Towards the end of the 1970s the plastic packaging sector had begun to grow, with the blow‐moulded PET bottle invented by DuPont. It was not until after the Second World War that general use of plastics in packaging applications started at a significant level. PE was mass produced during this period in Europe and became an easily obtained material from the late 1940s. At the beginning of this period it was a substitute for the wax paper used in bread packaging and still observed until the 1980s. The growth in plastic packaging use has accelerated at an astonishing pace since the 1970s. The technology available today and the requirements for a non‐perishable nature mean that many previously used materials (e.g. waxed paper) have been replaced by more suitable and economically viable materials such as glass, metal, plastic, paper, and cardboard. Before the 1950s packaging was essentially only used to protect the product during transport and storage. However, with the plethora of newer materials it has also begun to be used to advertise the product with the form, colour, printing, including fonts, and logos being a major part of the marketing process. This is simply because form‐differentiated packaging creates a distinction between the same types of products placed side by side on outlet shelves. The modern practice of favouring plastic as the packaging material of choice is, however, not without significant environmental concerns, with some amount greater than 15 million tonnes being present in the seas in 2017 and possibly as much as 30 million tonnes in 2019 according to recent estimates. The USA and Western European countries in 2000 consumed about 24% each of the world's plastics. Plastics such as PP are thought (based on chemical modelling and accelerated ageing study tests) to be able to persist in landfill for approximately 500 years. Single‐use plastics, which are discarded after one use (incinerated or sent for landfill), accounted for approximately 50% of all plastic packaging in 2019.

Glass‐based packaging is a form of packaging that has stood the test of time. This type of packaging first began to be used around 1500 BCE by artisans in Egypt. Glass, an amorphous silicate matrix, was first used in the form of a pot or vessel. Its fabrication starts when limestone, soda, sand, and silicates are co‐melted and shaped during the fluid phase at a temperature of many hundreds of degrees Celsius and allowed to cool into glass packaging. From about 1200 BCE, pots and containers started to be made from moulded glass on a semi‐commercial basis. Completely transparent glass was invented in the centuries following the development of reproducible blowing and with the aid of a ‘drawing pipe’ by the Phoenicians in 300 BCE. During the two millennia that followed, the development of clear (flint) glass, via augmented glass production techniques, has been incrementally improved and expanded to all manner of products. To date, the development of the automated rotary glass‐manufacturing machine