WHAT IS IT?
Polycarbonate (PC) is an engineering thermoplastic known for its exceptional impact resistance and optical clarity. It is produced from bisphenol A (BPA) and phosgene (or diphenyl carbonate in the phosgene-free process). Brand names include Makrolon (Covestro) and Lexan (SABIC).
KEY PROPERTIES
Impact strength: 250× stronger than glass, 30× stronger than acrylic (PMMA)
Optically transparent (88% light transmission)
Wide temperature range: usable from -40°C to +130°C
Good electrical insulation
Can be injection moulded, extruded, or thermoformed
GRADES
Optical Grade: Ultra-high purity for lenses and optical discs. Very tight colour and clarity specs.
General Purpose: Injection moulding, extrusion.
Flame Retardant: UL94 V-0 rated. Electronics housings.
Glass-Filled: Enhanced stiffness. Automotive structural parts.
KEY USES
Eyewear lenses (impact resistance + clarity)
Electronics: Laptop and phone casings, LED diffusers
Automotive: Headlight lenses, instrument panels, glazing
Building: Greenhouse panels, skylights, security glazing
Medical: Sterilisable equipment, blood oxygenators
DVDs, Blu-ray discs (optical grade — declining with streaming)
BPA CONCERNS
BPA (bisphenol A) — the monomer — is an endocrine disruptor. BPA-free alternatives are emerging in food contact applications. However, polymerised BPA in PC is generally considered safe by regulators.
TRADE CORRIDORS
Major producers: Covestro (Germany), SABIC (Saudi Arabia/Netherlands), Teijin (Japan), China domestic producers
Major buyers: Asia (China, South Korea, Japan), Europe
Tetra relevance: South Korea is a significant PC consumer for electronics manufacturing.
SPECIFICATIONS
MFI (Melt Flow Index): Grade-specific
Density: 1.20 g/cm³
Impact strength: Notched Izod >600 J/m
Heat deflection temperature: 130°C
Yellowness index: key quality parameter for optical applications