Polystyrene (PS) is the simplest plastic based on styrene. There are three general forms of PS film: • General purpose PS, • Oriented PS, • High impact (HIPS). One of the most important plastics is high impact PS or HIPS. This is a PS matrix that is imbedded with an impact modifier, which is basically a rubber-like polymer such as polybutadiene. 

Applications and uses: General Purpose—Yogurt, cream, butter, meat trays, egg cartons, fruit and vegetable trays, as well as cakes, croissants, and cookies. Medical and packaging/disposables, bakery packaging, and large and small appliances, medical and packaging/disposables, particularly where clarity is required, window envelope patches and labels. Oriented—Oriented-PS films can be printed and laminated to foams for food-service plates and trays offering improved esthetics. The films can also be used as a laminate to PS sheet for a high gloss shine for bakery and convenience food items.