Laminated glass is a special type of glass preferred in many applications due to its safety and performance characteristics. In the production of this unique glass, a thin Polyvinyl Butyral (PVB) film is placed between two glass layers. PVB creates an elastic bond between the glass layers, making the glass more durable. As a result, even if the glass breaks upon impact, the PVB film holds the glass pieces together and prevents them from scattering. Additionally, thanks to PVB's ultraviolet filtration properties, interiors are protected from the harmful effects of UV rays. With these features, laminated glass has become an indispensable part of modern architecture, automotive, defense, and maritime industries. The lamination process, which is one of the keys to producing durable, safe, and aesthetic glass products, is actually a process that appears simple but requires attention to many sensitive parameters. Among these parameters, humidity-controlled lamination room design is of primary importance. During the lamination process, the PVB film layer must be placed in a dust-free, dehumidified environment. NKT Humidity Control Technologies works with leading lamination manufacturers in Turkey and around the world with its lamination room solutions, providing precise humidity control in production areas through TFT silica gel rotor dehumidification units.
Why Humidity Control?
1. Quality and Appearance:
Moisture trapped between the glass layers during the lamination process degrades the visual quality of the product. This can lead to fogging or white spotting issues that may appear immediately after lamination is completed or over time. For end users, this can make the product aesthetically unacceptable.
2. Durability Issues:
Moisture can alter the properties of materials used during lamination. This may cause the glass to fail to meet expected mechanical properties or lose these properties over time.
3. Production Efficiency:
In lamination processes without humidity control, the rate of defective products increases. This leads to higher costs, reduced production speed, and an overall decrease in production efficiency.
How Is Humidity Control Achieved?
A series of steps must be followed to ensure humidity control before and during the lamination process.
Raw Material Control:
The humidity levels in the environments where the materials placed between laminated glass layers are stored must be kept under control. It is essential that materials have ideal moisture levels before entering the process. Although Polyvinyl Butyral (PVB) is a critical material in glass lamination, it can lose its properties or deteriorate if not stored properly. PVB has a high risk of being affected by moisture. When stored in a humid environment, it can cause changes in the material structure or the formation of bubbles. Such bubbles can lead to serious quality issues in the lamination process. At the same time, high humidity can weaken PVB film adhesion properties, which can cause unwanted separations during lamination or gaps between layers, as well as quality issues such as blooming. Therefore, humidity control during PVB storage is of vital importance. Careful control of humidity in the storage area and maintaining ideal moisture levels optimizes PVB performance and lamination application quality. For this reason, opened PVB rolls should also be stored at the same temperature and humidity values as the lamination room.
Production Environment Control:
Climate control of the laminated glass production environment, which involves adding a special polymer film layer (PVB) between two or more glass layers, is also extremely important. This film layer, called PVB, acts as an adhesive between the glass layers and keeps them together. During lamination, no dust, dirt, moisture, or other foreign materials should be present on the glass surface or on the film layer placed between them. Therefore, the area where the lamination process takes place must be a humidity-controlled clean room.
Particle Control and Filter Usage in the Lamination Room
The lamination room is a specially designed area where dust, microorganisms, and other foreign materials from outside are kept to a minimum. Maintaining clean room conditions during lamination directly affects product quality. Additionally, particle interference in the lamination process can cause significant drops in product quality and defective products.
The first stage of particle control is the ventilation system that provides air intake to the lamination room. The filters used in this system keep the air in the room clean. G4-F7 filters capture larger particles and improve overall air quality. These filters are particularly used to block particles such as dust and pollen from the outdoor environment.
However, due to the sensitivity of the lamination process, a higher level of filtration may be required. This is where H13-H14 HEPA filters come into play. These filters can capture 99.95% (H13) and 99.995% (H14) of particles 0.3 micrometers and larger. Such high-efficiency filters in the lamination room maximize air quality and minimize potential contamination on PVB films or other materials. While increasing the filtration level means reducing particles in the space, the resulting back pressure leads to the need for larger fans.
What Does Positive Pressure Ventilation Do in the Lamination Room?
Positive pressure ventilation works by maintaining the air pressure inside the clean room higher than the external environment. This prevents dirty air, dust, or microorganisms from leaking into the room. Clean air that has passed through the filtration system is continuously supplied to the clean room, preventing contaminated air from the outside from entering.
This system is critical for maintaining the quality of the lamination process. Any foreign material that could leak into the room can compromise lamination quality. Positive pressure ventilation minimizes this risk and ensures the lamination process is completed smoothly. The open PVB material used in the lamination room can emit a noticeable odor, especially during intensive use. This odor can negatively affect worker comfort. Therefore, it is critically important for the climate control system in the lamination room to provide continuous fresh air to effectively remove such odors. This both improves the quality of the working environment and ensures the lamination process takes place under optimum conditions.
In conclusion, climate control and humidity management in glass lamination is a continuous process that begins at the engineering design stage and extends through installation, requiring monitoring at every stage of ongoing production. For successful execution of the glass lamination process, the lamination room must meet humidity-controlled clean room standards and have a positive pressure ventilation system. These two factors are critical elements that directly affect the quality, durability, and overall production efficiency of lamination. This ensures that target temperature and relative humidity values within the space are kept under control and production continuity is maintained. At NKT Humidity Control Technologies, we understand how critical and sensitive the laminated glass production process is. That is why we continue to provide our customers with the right engineering solutions through innovative technologies in an energy-efficient manner.