250× the impact resistance of glass and 30× that of acrylic, with optical clarity above 88%. The material we reach for when machine guards, security glazing or process windows have to take a hit and stay intact.
Quick spec. Density 1.20 g/cm³ · service temperature −40 to +120 °C · tensile strength 60 to 70 MPa · Izod impact 600 to 800 J/m (notched, no break unnotched) · light transmission 88 to 90% · clear, tinted, UV-stabilised, fire-rated and abrasion-coated grades stocked.
Why polycarbonate is the impact-grade glazing
Polycarbonate is built around a bisphenol-A backbone, two benzene rings linked by an isopropylidene bridge, with the polymer chain joined through carbonate ester groups. The aromatic rings give the material its rigidity and high glass-transition temperature; the carbonate linkage absorbs energy and dissipates it through chain mobility. The result is the toughest transparent plastic in production: a 6 mm sheet will stop a hammer blow, and bullet-resistant glazing assemblies are typically PC laminate.
The trade-off versus acrylic is surface hardness. Bare PC scratches more easily than acrylic. Where abrasion is a concern we specify hard-coated PC sheet (Lexan® Margard, Makrolon® AR) which adds a silicone-based abrasion-resistant coating to both faces.
Engineering properties
| Property | Value | Notes |
|---|---|---|
| Density | 1.20 g/cm³ | Sinks in water |
| Tensile strength | 60 to 70 MPa | At yield |
| Tensile modulus | 2,300 to 2,400 MPa | |
| Izod impact (notched) | 600 to 800 J/m | Unnotched: no break at 23 °C |
| Service temperature | −40 to +120 °C | Glass transition Tg = 147 °C |
| Heat deflection (1.8 MPa) | 128 to 138 °C | |
| Light transmission | 88 to 90% (3 mm clear) | UV-grade absorbs 380 nm and below |
| Refractive index | 1.586 | |
| Surface hardness (Rockwell M) | 70 to 75 | Hard-coated grades equivalent to Mohs 6 |
| Fire performance | UL94 V-2 standard, V-0 grades available | Self-extinguishing |
| Chemical resistance | Good vs acids, salts, alcohols | Attacked by alkalis, ketones, esters and aromatic solvents, not for chemical-tank service |
| Joining | Mechanical fastening, hot-air welding (rare), structural adhesives | Avoid solvent welding, environmental stress cracking risk |
Where we use polycarbonate
Heavy-duty machine guards
Machine guards on press-brakes, lathes, conveyors and pinch-points. Sized to AS 4024 distance/aperture rules; CNC-routed with bonded edge frames.
Security and bullet-resistant glazing
Layered PC and PC-acrylic laminates for ATM facia, transaction windows, ticket-booth glazing, secure access control and prison fittings.
Skylights and architectural glazing
Multiwall and solid PC glazing for skylights, walkway covers, factory roof-lights, balustrade and façade work. UV-stabilised grades.
Process inspection windows
Where vibration, impact or low-temperature service rule out acrylic, PC sight windows give the same optical clarity with full impact reserve.
Formats and cut to size
Polycarbonate sheet is stocked in clear, tint and opal, usually 2440 by 1220 mm with oversize 3050 by 2030 mm available, across clear, tinted, UV stabilised, fire rated and abrasion coated grades. Cut to size on our CNC and laser routers. See sheet, rod and tube stock and cut to size plastic.
Standards and compliance, at a glance
- AS 4024, Safety of machinery (guard distance and aperture rules).
- UL94, Flame-spread classification; PC commonly V-2 with V-0 grades available.
- AS/NZS 4256, Plastic roof and wall sheeting.
- EN 356 / EN 1063, Security and ballistic glazing classifications (laminates).
Frequently asked questions
Polycarbonate has 250 times the impact resistance of glass and 30 times that of acrylic, with light transmission of 88 to 90 percent. A 6 mm sheet will stop a hammer blow.
Heavy duty machine guards sized to AS 4024, security and bullet resistant glazing laminates, skylights and architectural glazing, and process inspection windows where vibration, impact or low temperature rule out acrylic.
Bare polycarbonate scratches more easily than acrylic. Where abrasion is a concern we specify hard coated sheet such as Lexan Margard or Makrolon AR, which adds a silicone based abrasion resistant coating to both faces.
No. It has good resistance to acids, salts and alcohols but is attacked by alkalis, ketones, esters and aromatic solvents, so it is not for chemical tank service.
Minus 40 to plus 120 degrees service, with heat deflection at 128 to 138 degrees. Fire performance is UL94 V-2 standard with V-0 grades available.
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