Low-E glass is currently divided into two types: online Low-E glass and offline Low-E glass. The variety of online LOW-E glass is single.
Offline LOW-E glass comes in a wide variety of types. According to different climatic characteristics, products with high, medium and Low transmittance can be made. Moreover, in terms of color, there are silver-gray, light gray, light blue and colorless transparent, etc. With tinted glass, many other colors such as green can also be made. It can be made with a thickness ranging from 3 to 12mm. It should be noted that:
1. During the tempering process of online Low-E glass, it will be subjected to a high temperature close to the softening point of the glass. At this time, the color of the film may change somewhat, resulting in color differences. In addition, the tempering of online Low-E glass is film tempering. The presence of the film makes the heating on both sides of the glass asymmetrical, and the tempering process is difficult to control, which may cause a series of problems such as large tempering deformation. However, the offline Low-E glass is tempered first and then coated, so there is no problem. To avoid the above-mentioned tempering problems of online Low-E glass, some people use untempered online low-E glass as the inner sheet of insulating glass and place tempered transparent glass on the outside. This usage not only has a certain impact on the effect of Low-E glass in the south, but also may cause the stress spots on the outer tempered white glass to be magnified and aggravated by the inner Low-E glass. In contrast, there is no such problem when tempered offline Low-E glass is placed on the outdoor side.
2. The film surface of the single-piece offline Low-E glass is relatively soft and will oxidize slowly when exposed to moisture and certain oxidants.
3. The online Low-E glass is "hard coated", and the shelf life of the film layer is 30 years. Offline Low-E glass is a "soft-coated film" with poor firmness of the film layer and can hardly be stored exposed.
4. Offline Low-E glass must be processed into insulating glass in a very short time. Moreover, the edge coating must be removed when forming insulating glass. Due to the weak respiration of insulating glass, when water vapor, sulfides and oxides enter the cavity, it will lead to the gradual loss of the heat insulation performance of the offline Low-E glass, with a dark and discolored appearance and the gradual appearance of a large number of mold spots.
