Chemtough™ Chemically Toughened Glass
Resistance to fracture
Chemtough™ is much more resistant to breakage from thermal and mechanical stress than thermally toughened glass as a result of having surface compressive stress at least four times higher, typically over 400 MPa compared to 100 MPa for thermally toughened. Consequently it can resist much greater deflection without fracturing.
Applications
This property enables the design of thinner and lighter laminated glass windows in applications such as bullet and blast resistant glass; transportation safety glass in cars, trains, ships and aircraft, and windows in buildings subject to high wind load, storms or cyclones.
Available in all glass thicknesses
Chemtough™ can be manufactured in any glass thickness available, currently from 0.5 mm to 25 mm.
Advantages
Chemtough™ is not a safety glass but is usually supplied as a component of laminated safety glass. In this configuration it has a number of advantages compared to thermally toughened glass components as follows:
It will allow greater deflection without fracture, as a result of much higher surface compressive strength. This allows design of thinner and lighter windows, resulting in energy and material savings as well as ongoing energy savings in transportation applications.
If it fractures from impact, it will not form hundreds of small particles, but will have similar breakage characteristics to annealed laminated glass, so that the mechanical rigidity and integrity of a damaged laminated panel with be largely retained, as will visibility.
It is free of roller wave distortion and other deviations from flatness, so that it does not introduce any optical distortion in reflection or transmission, an issue that is inherent in thermally toughened glass, in particular when it is laminated.
Features, Attributes and Options.
Custom manufactured to clients’ requirements.
Highly resistant to thermal and mechanical stress.
Highly resistant to impact.
Zero roller wave distortion or deviation from flatness.
Available in sizes up to 3000 mm x 1500 mm in thickness from 0.5 mm to 25 mm.
Can be supplied as curved and laminated as required.
Can be incorporated to enhance performance and reduce weight and thickness of Glassguard® bullet resistant and blast resistant glass for architecture, transportation, marine and military applications.
GenuinelyCertified™
Architectural Products
FAQs
It's glass strengthened by ion exchange rather than heat. The glass is immersed in a molten potassium salt bath at about 400°C, where larger potassium ions replace smaller sodium ions in the glass surface. The larger ions crowd the surface, creating a compressive layer that makes the glass much harder to break.
Thermal toughening uses rapid heating and cooling to create surface compression; chemical toughening uses ion exchange. Chemical strengthening works on thin glass (under 3mm, where tempering isn't possible), causes no optical distortion (no roller wave), and doesn't warp the glass.
Surface compressive stress is higher — chemically strengthened glass is typically in excess of 400 MPa versus roughly 100 MPa for thermal toughening.
No. When it breaks, it fractures into large pieces similar to annealed glass rather than small dice. That means it is not classified as safety glass on its own — for safety applications it is laminated.
Smartphone and tablet cover glass, aircraft and high-speed train windows, bullet and blast resistant glass, marine glazing, instrument covers, camera lenses and displays, thin laminates, and applications where thin, light, optically perfect strong glass is needed.
Cutting after chemical strengthening is technically possible (unlike toughened glass, it won't explode), but it's discouraged — cutting removes the compressive edge and dramatically weakens the part, and edges must be re-worked. Best practice is to cut, drill, and edge-finish before the ion-exchange process.
Very thin — down to well under 1mm (ultra-thin flexible glass at 0.1–0.5mm is chemically strengthened). This is its biggest advantage: thermal tempering generally can't handle glass below about 3mm.
The salt bath immersion typically lasts several hours to 24+ hours depending on the glass and target strength — much slower than thermal toughening (minutes). Combined with batch processing, that makes it significantly more expensive per unit area, which is why it's mostly used where thermal toughening is not possible or is inadequate.
The surface compression gives some added resistance to scratch propagation, but chemically strengthened glass is still glass — it scratches.
Under normal conditions the ion-exchange layer is stable for the life of the product; strength loss comes from accumulated surface damage rather than the treatment "wearing off."