Intermediate film material properties
There are various types of interlayer films for Laminated glass, the common ones are polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), etc. Different interlayer materials themselves have different UV blocking capabilities. For example, PVB film has a certain absorption and blocking effect on ultraviolet rays. Its molecular structure can absorb ultraviolet rays in a specific wavelength range, thereby reducing the transmission of ultraviolet rays. Some specially formulated intermediate films, such as EVA films with added UV absorbers, can significantly enhance the UV blocking effect. These ultraviolet absorbers can be organic compounds that can convert ultraviolet energy into harmless heat or other forms of energy to prevent ultraviolet rays from penetrating the glass and causing damage to people, furniture and decorations in the room.
UV blocking principle
When light shines on Laminated glass, the ultraviolet rays first come into contact with the interlayer film. The UV blocking component in the interlayer works by absorbing, reflecting or scattering UV rays. For the absorbing interlayer film, after the chemical substances inside the film absorb ultraviolet rays, the electrons will transition, causing the energy of the ultraviolet rays to be consumed and unable to continue to propagate. The reflective interlayer uses a special optical structure or coating to reflect ultraviolet rays back so that they cannot enter the inside of the glass. The scattering interlayer film scatters ultraviolet rays within the film, changes its propagation direction, and reduces the probability of it transmitting through the glass. The UV blocking principle of different interlayer films may be a single one, or it may be the synergy of multiple mechanisms, depending on the specific formula and structural design of the interlayer film.
Combination effect with glass
The ultraviolet blocking ability of laminated glass not only depends on the interlayer film, but also is related to the characteristics of the glass itself. Ordinary glass has a certain blocking effect on ultraviolet rays, but glass with different thicknesses and compositions has different ultraviolet transmittances. When combined with the interlayer film, the two work together to further enhance the UV blocking effect. For example, in some application scenarios that require high UV protection, glass with low UV transmittance is selected to be combined with an interlayer film with strong UV blocking ability. The glass can block some ultraviolet rays, and the interlayer film further absorbs or reflects the remaining ultraviolet rays, thereby greatly improving the overall ultraviolet blocking rate of Laminated glass and effectively protecting indoor items from ultraviolet rays such as aging and fading.
Selection and Application Considerations
In practical applications, when selecting the interlayer film of Laminated glass to meet the UV blocking requirements, multiple factors need to be considered. First of all, the environment and purpose of use must be considered. If it is used for the protection of museum cultural relics, it requires an extremely high UV blocking rate. An interlayer film containing a high-efficiency UV absorber may be selected and paired with special low-transmittance UV glass. Secondly, cost must be considered. The prices of different interlayer materials and formulas vary greatly. On the premise of meeting the basic requirements for UV blocking, cost and performance must be weighed. In addition, the bonding performance between the interlayer and the glass, the adaptability of the processing technology, etc. must also be considered to ensure that while the Laminated glass has good UV blocking capabilities, the overall quality and performance are stable and reliable, and can adapt to different installation and use conditions.
