In 1927, car manufacturers switched to using laminated safety glass for windshields. This date is important. Before that, a shattered windshield meant flying shards. Now that means trouble and repair costs.
The structure is a sandwich. Two sheets of glass trap a thin layer of polyvinyl butyral (PVB). This transparent plastic film is the star. The glass may break if exposed to impact. PVB holds the parts in place. It absorbs energy. It stretches without tearing. This prevents the glass from becoming a flying object inside the car.
It is also a barrier. Laminated safety glass is more difficult to break than ordinary window glass. This “sandwich structure” allows occupants to remain inside the vehicle in the event of a rollover. This principle can also be seen in bank vaults. Bulletproof glass uses multiple layers of laminated glass to stop flying objects.
The hidden benefits of auto glass lamination
In addition to safety, laminated safety glass has two unique advantages for everyday driving.
First, it blocks high-frequency sounds. You may not notice the sound reduction right away, but it reduces road and wind noise. It acts as silent protection.
Second, it filters the light. Laminated safety glass blocks 97% of UV rays. Your skin and interior upholstery get less damage from the sun. This is beneficial for both your skin and your dashboard.
Where else does this glass appear?
You may not realize it, but laminated safety glass is everywhere in our daily lives. It’s not just about cars.
- Thermometer : The protective layer of digital thermometers is usually laminated glass.
- Cutting Board : Some heavy duty kitchen boards use this for added durability.
- Greenhouse : The windows here must be able to hold together if hit by of hail or debris.
- Shower room : When it’s wet and slippery, safety is the most important thing.
- Office Partition : Privacy screen, won’t shatter into danger if bumped.
This material also prevents it from falling off the frame in the event of an extreme event such as an earthquake or tornado. It stays put. It holds the structure together.
Tempered glass: The Other Side of Safety
Laminated glass is not the only safety glass for cars. The side and rear windows are tempered safety glass. This is a single piece of glass, not a laminate.
The process is different. The glass is heated to a high temperature. Then let it cool immediately. This thermal shock causes the material to harden. Tempered glass is five to ten times stronger than untempered glass.
The failure mode is the key difference. Ordinary glass shatters into sharp, jagged pieces. Tempered glass explodes into tiny, dull pebbles. These parts have no sharp edges. They are less likely to cause deep lacerations. This is why your side windows are tempered. In an emergency, you can break them out. These shards are harmless compared to the jagged chips of ordinary glass.
Chemical tempering is also used for eyewear. It strengthens glasses without the thermal process.
Non-automotive applications
Tempered safety glass is widely used in applications where strength and safety are important.
- Computer screen : Screens are usually hardened to withstand impacts.
- Liquid Crystal Display (LCD) : Improves panel durability.
- Skylight : Needed to dampen the impact of falling objects and debris.
- Fridge Shelf : Glass shelves can store heavy items without breaking easily.
- Oven door : It must withstand extreme temperature changes.
- Storm Door : Protects against weather and impacts.
