PS plastic (polystyrene)

What is PS plastic?

Polystyrene (PS) is a vinyl thermoplastic polymer. On the industrial market, two main families coexist depending on mechanical requirements:

• Crystal PS (GPPS): rigid and transparent in its natural state, it offers an excellent surface finish and good dimensional precision, but remains brittle under impact.
• High-impact PS (HIPS): modified by the addition of rubber (polybutadiene), it gains significantly higher impact resistance while retaining good rigidity, at the cost of an opaque appearance.

The main properties and advantages of PS

High-impact PS is particularly valued for appearance parts produced in mid-range volumes, thanks to a highly competitive quality/cost ratio:

• Mechanical properties: good rigidity, high surface hardness and satisfactory dimensional stability for non-structural parts.
• Thermal properties: it withstands service temperatures up to approximately 70 °C to 80 °C continuously.
• Aesthetic properties: it offers an excellent surface finish, good printability and markability, as well as a wide range of mass-coloured shades.
• Economic advantage: it is one of the most accessible thermoplastics on the market, particularly suited to parts not subject to significant mechanical stress.

The limitations of PS: which applications should it be avoided for?

As experts, it is our duty to guide you towards the right material. PS has certain limitations to be aware of:

• UV sensitivity: PS tends to yellow and weaken if exposed to sunlight for extended periods. For prolonged outdoor use, we will direct you towards a UV-stabilised grade or a more suitable thermoplastic.
• Low solvent and grease resistance: it is sensitive to strong solvents, oils and certain fats, which can cause stress cracking (crazing).
• Limited impact resistance for crystal PS: the transparent version remains brittle. For applications subject to impact, we systematically direct towards high-impact PS or another technical material.

How does Plastisart process PS?

PS has the advantage of being an easy plastic to process within short lead times. At Plastisart, we work with it daily through different processes:

• Vacuum thermoforming: high-impact PS is one of the most widely used plastics in thermoforming. It stretches homogeneously, faithfully reproduces mould details and shows low and predictable shrinkage on cooling.
• CNC machining: it is easily milled, turned and drilled. It generates clean chips and allows precise dimensional tolerances to be achieved for prototypes and small series.
• Hot bending: PS bends well for producing simple housings or display units without requiring a mould.
• Assembly and finishing: it is a plastic that bonds well with suitable adhesives and readily accepts painting, marking and screen printing.

Industry sectors and typical industrial applications

Thanks to its excellent surface finish and controlled cost, PS is found in many sectors for the manufacture of:

• Display units, totems and indoor signage structures
• Housings and claddings for household appliances and consumer electronics
• Trays and technical non-food packaging parts
• Mock-ups, prototypes and pre-series parts
• Appearance parts for furniture and fittings

Why choose Plastisart for your PS parts?

Processing PS requires good mastery of thermoforming to preserve its surface finish and anticipate its cooling behaviour. At Plastisart, you benefit from a permanent stock of high-impact PS sheets (various thicknesses and shades) for maximum responsiveness on your lead times. Our integrated design office validates your drawings and delivers complete finished parts and sub-assemblies, ready to use, at a particularly competitive material cost.

FAQ about PS