What is High Impact Polystyrene?

High impact polystyrene, or HIPS, is a versatile plastic resin used in the manufacture of numerous products. Easy to fabricate, this resilient material costs little to produce and offers applications in many industries. Its physical properties permit flexible machining and surface applications such as paints and adhesives. The material can be used as packaging filler, pressed into board, molded into products, or delivered on sheets or rolls. Its characteristic dimensional stability permits it to be employed in low strength construction, and in its natural translucent form makes it suitable for food processing applications.

Tougher than polystyrene, this thermoplastic polymer material has many strengths. It imparts impact-resistant characteristics, for example, in the construction of toys. With its combination of stable construction and easy surfacing, high impact polystyrene makes housings and covers that are easily mass produced. This common material comes in many colors and appearances. Some disadvantages include increased moisture absorption, as well as reduced transparency and electrical properties.

Produced by a process of thermoforming, high impact polystyrene products can be constructed with mechanical fasteners or through the use of adhesives and solvents. Grades used for printing are found in processes including screen-printing, flexography, and offset lithography. In the home, it appears in ceiling tiles, insulation, and kitchen utensils. Commercial applications include shop displays, placards, and banners. It provides a more durable alternative to poster paper for craft projects.

Other properties of high impact polystyrene include heat resistance and durability to temperatures well below freezing. It can undergo ethylene oxide (ETO) sterilization, or that of gamma or electron beams, in compliance with government-approved standards of food safety. HIPS emits no noxious fumes or corrosives and is often available in recyclable grades.

Brittle and water-white, this thermoplastic is polymerized from styrene, or phenylethylene, and toughened with the addition of butadiene to form a copolymer. Butadiene is a flammable, colorless gas used in the manufacture of synthetic rubbers; it is highly reactive and polymerizes readily. This styrene-butadeine copolymer is used to produce resins for paints, rubber, and high-impact plastic.

The manufacturing process of vacuum forming permits this material to be shaped to suit its application. Multiple grades of high impact polystyrene serve different purposes. The material can be formed into films as thin as 0.029 inches (about 0.074 cm) and less. Textures possible with this versatile material are as varied as its available colors. As a material used in commercial, industrial, and residential contexts, HIPS provides familiar and innovative new uses.