PET is available in a wide variety of different grades that are distinguished by characteristics such as the molecule length and level of crystallisation, allowing the material to be tailored to meet specific needs.
Container manufacturers such as Petainer receive PET resin in the form of small cylinders called pellets. These are melted at 270°Cand injected under high pressure into a mould to make a preform – a test tube shape that is smaller than the finished container that it will become but with thicker walls.
The preform is then reheated to around
110°C and blow-moulded into its finished form in a separate machine by injecting high-pressure air that forces the material into the exact shape of the water-cooled mould in which it is placed.
The productivity of the industry has increased enormously since Petainer first began making PET bottles in 1983. Injection moulding machines used to have 16 preform cavities per injection mould. They now contain up to up to 144 preform cavities per injection mould and can produce around 1,600 bottles per blow mould per hour.
Temperature resistance
PET containers can be used in ‘hot-filling’ systems which are used by some food and beverage manufacturers to package their products because the high temperatures – typically around 85°C – kill micro-organisms.
PET containers are also available for use in pasteurisation systems operating at temperatures up to around 60°C.
Barrier technologies
PET containers are now available with both passive and active barriers to maintain carbonation levels and to protect against oxygen permeation.
Sustainability
Reducing the amount of material used in making a container aids both sustainability and economy. Petainer is a leader in ‘lightweighting’ containers to use less material. In 1980, a typical two-litre PET bottle weighed 68 grams. Today it typically weighs only 47 grams.
Safety
The safety of PET has been repeatedly demonstrated through extensive studies, regulatory approvals and scientific testing. Like glass, it is strong, resistant to attack by micro-organisms, does not react with foods and will not biologically degrade. However, unlike glass, PET is extremely lightweight, simple to transport and will not break, which is why it is preferred for packaging many foods and beverages.
Petainer technology
Petainer is a leader in the design, sale and manufacture of value-added, custom blow-moulded PET containers and preforms for branded consumer products. We use technology and innovation to deliver solutions that meet our customers' needs for new designs, product performance requirements, cost management and sustainability. Our strong design capabilities have been especially important to our customers, who use our packaging to differentiate and add value to their brands.
At Petainer we can meet our customer’s needs for containers ranging from 200 ml bottles to 40 litre kegs.
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