Plastic Injection Moulding Specialists. Est 1948.

We are experienced in the way Polypropylene behaves when injection moulded and are able to design in features that will maximise the properties strengths and eliminate its weaknesses.

The shrinkage of Polypropylene is largely influenced by processing conditions, hence, ultra close dimensional tolerances on mouldings are difficult to achieve. On the other hand, for assembly purposes, the resilience and resistance to stress cracking of polypropylene diminish the need for close tolerances.

Polypropylene –S.B.Weston’s packaging and storage box production occurs in Polypropylene due to the materials resistance to fatigue, its light weight toughness, rigidity and excellent resistance to chemical attack or ‘leeching’ all of which which make it very suitable for our range of storage boxes.

Live plastic hinges are often made in polypropylene. The material is selected due to its resistance to corrosion and chemical leeching and its resilience towards most forms of physical damage such as impact and freezing.

S.B.Weston use three main grades in the production of our boxes: A Polypropylene Homopolymer for our Regular Boxes which while strong, is not impact resistant and becomes brittle in very low temperatures. A toughened Copolymer – our TOUGH Boxes – which is impact resistant even at low temperatures, but is a whitish semi-opaque color in its natural state. And a Random Copolymer which combines the improved toughness of the toughened copolymer with the transparency of the regular homopolymer.