What should be done when the winter curtain wall sealant "bulges"? (Usually manifested as bubbles forming inside the sealant joint, bulging or uneven surface) is a relatively common but important issue. This is not only a matter of appearance, but also may affect the water tightness, air tightness and durability of the curtain wall. The following are the main causes, preventive measures and solutions for the bulging phenomenon during winter:

The first step in selecting the adhesive is to look at its appearance. We should check whether the surface of the adhesive is smooth, if there are any particles, and how much the bubbles have shrunk. The second step relies on the sense of smell. Based on the different types of small molecules released by silicone sealant during curing, we classify it into neutral sealant and acidic sealant. Among them, the acetic acid small molecules released by the acidic sealant during curing give most users an overly stimulating experience, and it can also corrode alkaline substances and metal substrates.

For single-component weather-resistant sealant, when applied in cold weather, there may be a problem of slow curing. Generally speaking, when the environmental temperature is low, the curing speed slows down; when the environmental humidity is low, the curing speed also slows down. Therefore, in cold weather, the surface drying, debonding and deep curing of the sealant will all slow down.

There are several reasons: 1. The poor adhesion to the substrate causes the delamination phenomenon, which usually occurs at the edges of the joint. 2. During the initial curing process of the sealant, the joint deforms excessively, resulting in cracks in the middle of the joint. 3. The thickness and width of the applied sealant do not meet the specification requirements. If the thickness is too thin or the contact width is too narrow, it will lead to damage or bond failure during use. If the thickness is too thin, it usually results in cracking in the middle. If the contact width is too narrow, it usually causes cracking on the sides. 4. Poor quality sealant (oiled sealant) was used. After a period of time, the sealant loses elasticity and cracks, and the cracks have no pattern.

First, apply the sealant strip onto the plastic film. Every 5 minutes, gently touch the sealant strip with your fingers. When your fingers no longer stick to the sealant, record the time taken. This time is the "table drying time". After the sealant has cured for 24 hours, touch the sealant with your palm to check if it is sticky. When the sealant is fully cured, slowly stretch it to 100%, hold it for 5 seconds, then check if there are any cracks and if it can basically return to its original state. Finally, determine if the elasticity is good. If all three indicators are met, it indicates that the sealant quality is qualified. If any of the indicators do not meet the requirements, it means that the sealant has quality issues.

Door and window sealant is a single component sealant that gradually solidifies from the surface to the inside by absorbing water molecules from the air. It is easily affected by environmental temperature and humidity, with a conventional curing speed of 2-4mm/day. In general, the reasons for slow curing are: 1. Curing is slower in environments with low temperature or humidity 2. Deep sealant seams have slow curing of the internal adhesive 3. The curing speed of different types of sealants also varies 4. Unreasonable storage conditions or exceeding the shelf life