For many years, the multi-component technology in plastic injection moulding has been an established manufacturing process. Thanks to the multi-component technology, a production plant can produce products that would normally require several injection moulding machines or other downstream processes.
This leads to a reduction of investment and logistics costs. The costs for quality assurance are also lower compared to the use of conventional technologies and manufacturing processes. Furthermore, the lead time for the production of the components can be significantly reduced.
With the multi-component injection moulding technology, it is possible to realise products with a broad spectrum and complex properties, such e.g. different materials, multiple colours or with integrated functions.
In classical multi-component injection moulding technology, a produced preform is over-moulded in a subsequent process. This process is repeated until the final shape is achieved. Depending on the application, the materials used differ in their colour and properties (typically combinations of hard and soft components).
Co-injection technology
The co-injection technology is a specific application of the multi-component injection moulding technology.
In contrast to traditional multi-component injection moulding, co-injection moulding involves injecting two different plastics simultaneously through a nozzle to form a multi-layered structure (also called multi-layer technology). This technology is mainly used in food packaging and has its origins in the beverage industry (PET bottles).
With the co-injection moulding technology, a barrier layer is embedded in a standard plastic. The barrier protects the product to be packaged against external influences, in particular it keeps the oxygen away and preserves the quality of sensitive and perishable products. The oxygen barrier increases the shelf life of the product, since the oxidation process is prevented or reduced. Areas of application are e.g. fruit juices, coffee, caviar, dairy products, baby food.
Thus, the food manufacturers receive a cheap, flexible and safe alternative to traditional packaging. The weight saving is another and significant advantage of the co-injection moulding technology compared to metal (up to factor three) and glass packaging (up to factor 20). A lower environmental impact is resulted due to reduced use of material and lower transport weights.
Applications outside the food industry can also be found in the medical, pharmaceutical or chemical industries.
The co-injection technology enables a highly efficient production of the packaging with highest precision. The packaging is manufactured in one step, which leads to cost advantages in terms of required investments, logistics and quality assurance.
In addition, technologies such as in-mould labelling (IML) allow packaging to be differentiated efficiently and customer-specifically. The choice of coloured plastic granules allows further design variants, which can be implemented quickly and flexibly in production.
Currently, there is increasing interest in solutions with co-injection moulding technologies, in particular due to the development of new plastics and barrier systems.
