Laminated glass plays an important safety role: the combination of glass and interlayer film ensures stability and security, protecting against injuries in the event of an accident. But how does this invisible protection work? How is the complex bond between glass and film created—and what innovations are making laminated glass a true multi-talented material today? You’ll find the answers in this article.
Laminated glass differs significantly from standard single-pane glass. Single-pane glass consists of one sheet and breaks under high stress. Laminated glass, on the other hand, is made of at least two glass sheets bonded together with a PVB interlayer (PVB = polyvinyl butyral). This composite holds the shards on the film and reduces the risk of injury. For example: in the event of a stone impact or accident, only the outer layer of a windshield breaks, while the inner layer remains intact and protects the vehicle’s occupants.
Laminated glass is produced manually, semi-automatically, or fully automatically. Both individual panes and series production, as well as large formats up to twelve meters in length, can be manufactured. Regardless of whether it’s a single pane or a series, manual or automated: the production process is essentially always the same. Before a glass pane is prepared for lamination, it is washed. In the next step, the glass panes are assembled with PVB film in a cleanroom to form what is called a “sandwich” or “glass package.” The prepared sandwich then enters the pre-lamination process.
The simplest way to create the pre-laminate is the vacuum bag method. The glass package is placed in a flexible bag, the air is evacuated, and heat is applied. Through the combination of vacuum and heat, the film bonds chemically and mechanically with the glass. The result is a stable pre-laminate in which the panes already adhere to each other but are not yet finally pressed. Final strength and bonding are achieved later in an autoclave.
In modern production facilities, pre-lamination takes place in continuous processes. This allows for high volumes to be produced quickly while ensuring optimal conditions for different film types or glass sizes. The sandwich passes through an oven calibrated to the different absorption rates of glass and PVB film. Infrared heaters and warm air convection provide uniform heating. The glass is then joined under high pressure in a roller press, removing trapped air and mechanically integrating the film into the pre-laminate.
The PVB interlayer is crucial for the stability and safety of laminated glass. The thickness of a standard film ranges from 0.38 mm to 4.56 mm. For applications with high safety requirements—such as skyscraper façades or regions exposed to extreme weather events like hurricanes or tropical storms—high-performance films are used. These films offer greater strength and elasticity.
Today, interlayers no longer serve only as protective or stabilizing elements. In recent years, they have evolved into multifunctional materials with high-end features that open up entirely new fields of application. Examples include:
As in all areas, sustainability and recycling play an important role in the production of laminated glass. Automated pre-lamination processes not only enable faster production but also support resource-efficient operations. Optimized workflows and reduced film waste help lower material consumption and energy requirements.
Beyond resource conservation during manufacturing, the recycling of laminated glass is becoming increasingly relevant. The goal is to separate the composite material at the end of its life cycle, process the glass and film components, and reintegrate them into production. Reusing glass remnants for remelting in glass manufacturing also saves energy, as less new raw glass needs to be produced.
Laminated glass is a prime example of the innovative strength of the glass industry: from individual pieces to series production, from manual to fully automated processes, and from “simple” laminated glass for windshields to high-end solutions with integrated LEDs or dimming functions—many things that once seemed futuristic are already reality today. So, we can look forward to even more exciting developments in the future.
Learn more about laminated glass in our podcast LiSTEN LiSEC.