In the actual use of silicone sealants in the first and second seals of insulating glass, the bonding performance is one of the most basic and important properties. It is related to the durability of the seal and even the safety of building components. Interfacial interactions between stickies produce good adhesion. So what are the main factors that affect the bonding of insulating glass silicone sealant to the glass substrate?
Choose the right sealant
Since the invention of silicone sealants, after nearly 80 years of development, the types of silicone sealants have been very rich. When selecting insulating glass sealants, the compatibility between the sealant and the substrate should be given priority. Choose the right sealant for the difference. Some glues will react with the substrate and corrode the substrate; some glass substrates themselves avoid silicone glue and cannot bond.
Figure 1 How to choose the insulated glass silicone sealants 1
When selecting the silicone sealant for insulating glass, it should be ensured from LIJIANG Glass that the silicone sealant can achieve good adhesion to other materials except for a few substrates such as copper, PP, and PE. (Among them, a very small number of metals such as copper will react with the sealant to cause self-corrosion; organic glass substrates such as PP and PE cannot form molecular chains with silicone sealant due to their high molecular crystallinity and low surface tension. and tangle.)
A clean substrate surface is very important
The existence of dust and dirt will reduce the contact area between the glue and the substrate surface, which may cause stress concentration when the force is applied, thereby causing the sealant to be destroyed in advance; oil stains may cause the sealant to dissolve and fail; rain, snow, and frost may cause The sealant cannot bond. Therefore, try to clean the glass substrate before applying the glue, and let it be clean and dry, so that the sealant can be fully bonded.
Apply primer when needed
Generally, silicone sealants have good adhesion to metals, but with the advancement of technology, surface treatment methods for doors and windows aluminum profiles emerge in an endless stream. There was a marked difference in adhesion. Don't panic when you encounter this situation, the primer will appear at the critical moment. Primer, also known as primer, is composed of different solvents and coupling agents.
For aluminum profiles for doors and windows, the solvent has a certain cleaning ability, and the coupling agent modifies the surface of the profile, thereby enhancing the sealant and adhesion between profiles.
The steam setting should be reasonable
When applying glue, especially when using an automatic insulated glass sealing robot line, in addition to paying attention to the reasonable glue width and glue depth, it is also necessary to avoid three-sided bonding, because three-sided bonding will seriously affect the displacement capacity of the sealant, resulting in Cracking due to excessive internal stress.
Figure 2 The reasonable insulated glass sealant glue width and glue depth 1
Do does not use in a water-immersed environment
Although the curing of silicone sealant is inseparable from the participation of water, it cannot be soaked in water for a long time because of its structural composition. Performance is bound to degrade.
Protect before fully curing
No matter what kind of sealant it is, it is very fragile when it is not fully cured. After it is fully cured, its durability and weather resistance are very strong, and various excellent properties can be exerted. Therefore, the stress on the sealant should be avoided as much as possible during the period from sizing to complete curing.
For glass processing practitioners to use glue happily, LIJIANG Glass recommends the standard glue purchase process for customers: compatibility and adhesion tests before purchasing glue; small-area glue tests before large-scale glue application; fixed time during use Interval checks.
Figure 3 The small area insulated glass sealant glue experiment 1
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