High Density Polyethylene (HDPE) is a thermoplastic with a high strength-to-density ratio. This makes it the perfect material for plastic bottles.
Other identifying characteristics, which may cause a producer to specify the use of it rather than any other type of plastic, include the fact that it has a high-density, is taut with a good temperature resistance, all of which relates to its lack of chemical branching, and has an excellent water-vapour barrier.
HDPE bottles are also lightweight and food-and-beverage safe. The translucent nature of HDPE bottles makes it possible for consumers to view the amount of product still inside
Examples of the types of HDPE bottles you are likely to come across in daily life include:
HDPE bottles come in all shapes, sizes and colours
1868: John Wesley Hyatt developed celluloid from a mixture of shred tissue paper, nitric acid and sulfuric acid. This first man-made thermoplastic is still used today for photographic film.
1891: Rayon was developed by Louis Marie Hilaire Bernigaut which, along with cellophane, were the precursors to the “plastics craze” of the roaring 1920s.
1907: New York chemist Leo Bakeland created Bakelight, which the military found useful in the production of weapons, as well as for electrical insulators, radios, cups, buttons, false gums and silverware handles.
1908: Dr Jacques Edwin Brandenberger discovered cellophane by applying liquid viscose to cloth – the aim being to make it waterproof. Although the experiment failed, the substance peeled off the cloth in a transparent film, which was a breakthrough.
1940s: Nylon, acrylic, neoprene, SBR and polyethylene were becoming widespread. In fact, between 1940 and 1945, the demand for plastic in the US grew immensely, tripling in production due to the war, public funding, oversight and the material’s versatility.
A range of inventions and discoveries gave way to various different types of plastic, including PVC or vinyl (found in vegetable oil bottles and food wraps), SaranTM, Teflon, PET (used in beverage and food containers), HDPE used in the making of milk and detergent bottles), LDPE (creates plastic bags and shrink wrap), PP (found in margarine and yoghurt containers) and PS (used to make egg cartons and disposable utensils).
1970s: Plastic bottles first came into regular use for soft drinks.
1977: The weight of these bottles was reduced from around 60 grams to just 48 grams.
1990: The highly progressive Coca-Cola Company began blending recycled plastic into its plastic beverage bottles.
2010: David de Rothschild led a crew on a 12 000-nautical-mile sea mission on Plastiki, which was the first ever ship created from recycled plastic bottles – with the movement towards sustainable living being a top priority among the eco-conscious.
First off, three heated holding tanks commence the process – the primary one containing a natural gas derivative called ethane. The ethane is heated to well above boiling point (i.e. above +100°C) and is then pumped into a mixing tank.
From the third tank comes benzene which, when combined with UV radiation from a set of overhead lamps, serves to bring about the polymerization of ethane.
While this process describes how polyethylene is made, there is still a treatment process that the polyethylene needs to go through to become high-density polyethylene (HDPE). This involves pumping the chemical into a series of metal troughs that are wide, shallow and board-like. Instead of being allowed to cool, it is cooked at a low heat to allow for the release of any captured air and oxygen.
Next up, the troughs drain into a further series of upright metal molds that contain shredded wood fibre. Once the material has been allowed to cool for approximately eight hours, the HDPE boards can be shipped to retailers and wholesalers for use in various product
In what ways are HDPE bottles superior to those made from other materials?
it is recycled with greater ease