How to choose insulating glass sealant?

There are three common insulating glass sealant: silicone, polyurethane and polysulfide, but due to polysulfide adhesive, polyurethane adhesive has poor ultraviolet aging resistance, and the bonding surface with the glass will easily degummed if it is exposed to the sun for a long time, which will lead to the outer sheet of the insulating glass curtain wall of the hidden frame glass falling off or the insulating glass seal failure of the point-supported glass curtain wall. The molecular structure of silicone sealant makes silicone sealant have the advantages of excellent high and low temperature resistance, weather resistance and ultraviolet aging resistance, while the water absorption is very low, so the market is mainly based on silicone rubber.

• 1. What is the harm of improper selection of insulating glass second sealant?
  

One is easy to lead to the failure of insulating glass; Second, the insulating glass outer pieces fall causing safety hazards.

(1) The main reasons for the failure of insulating glass are:

1.The first sealant butyl rubber itself quality problems or incompatibility with silicone rubber phenomenon;

2.Insulating glass second sealant containing filled mineral oil;

3.Contact with oil-filled adhesive, such as weather-resistant adhesive for curtain wall joints or sealant on doors and Windows;

4.Other such as molecular sieve desiccant or construction problems.

(2) The outer piece of insulating glass falls

Glass curtain wall hollow glass sheet glass falling phenomenon occurs from time to time, seriously endangering personal safety. The glass falling phenomenon of the insulating glass outer piece of the glass curtain wall mainly exists in the fixed and open part of the hidden frame and semi-hidden frame glass curtain wall or the open part of the open frame glass curtain wall, especially when the wind or rainy days pass, the glass falling phenomenon is more serious, and it is easy to induce safety hazards.

In the identification of curtain wall quality accidents, it is found through analysis that the reasons for the fall of the outer sheet glass mainly have the following three aspects:

1.The compatibility of insulating glass sealant;

2.In order to save costs, the relevant parties blindly pursue low prices, insulating glass second sealant using non-silicone structural sealant issues such as polysulfide and silicone building sealant;

3.Some construction personnel are not professional, not rigorous caused by the insulating glass sealant injection width problem.

2.What should we pay attention to when choosing the second insulating glass sealant?

(1) Meet standards and use as needed

It is recommended to use insulating glass silicone structural adhesive for the second insulating glass sealant of large-size open-frame curtain wall;

Silicone structural sealant must be selected for the secondary insulating glass sealant of point-supported glass curtain wall;

Second insulating glass sealant for doors and Windows and ordinary bright frame curtain wall can be selected insulating glass silicone sealant, polysulfide sealant or polyurethane sealant.

Because the hollow glass sealant used for hidden frame, semi-hidden frame and point support glass curtain wall is subjected to the wind load and self-weight load of the outer glass, the adhesive strength of the sealant is required to be high. Although the bonding strength of silicone adhesive and polysulfide adhesive is high, due to the poor ultraviolet resistance of polysulfide sealant, and the poor compatibility with the silicone sealant used in the curtain wall, the insulating glass that bears the load, such as the hidden frame, semi-hidden frame and point support glass curtain wall, the second sealant must be made of silicone structural sealant.

Because most insulating glass production enterprises are not very clear or understand the performance index requirements of insulating glass in the building curtain wall and other aspects of the use of insulating glass, in addition, curtain wall construction enterprises can not propose the particularity of the customized insulating glass second sealant to the insulating glass production enterprises. In this way, the use of polysulfide sealant by production enterprises is also one of the main reasons for the loss of insulating glass outer sheet glass.

In addition, in the bright frame glass curtain wall, the fixed plate insulating glass second sealant can use polysulfide sealant, but many people ignore the open part, because the open part of the bright frame glass curtain wall is designed according to the hidden frame structure. This point is often ignored by most curtain wall companies, opening part of the insulating glass second sealant does not use silicone structural sealant, resulting in the open part of the insulating glass curtain wall falling seriously.

(2) Do not use oil-filled sealant

With the increasingly fierce market competition, some bad manufacturers in order to reduce production costs, at the expense of sealant product performance and quality to seek short-term profits. Filling cheap "mineral oil" instead of expensive silicon-based polymers is a common way for poor manufacturers to reduce sealant production costs. Behind the low durability of cheap oil-filled adhesive is the premature failure of insulating glass or even the fall of insulating glass outer pieces, which may cause major safety hazards. Therefore, we must refuse to use "oil-filled glue".

Insulating glass secondary sealant accounts for a small percentage of the cost of insulating glass, but it is very important for the durability and safety of insulating glass applications. It is recommended that customers must choose the right product, such as the pursuit of low prices and ignoring the correct application and quality assurance of the product, which may lead to quality problems of curtain wall doors and Windows, and even cause major safety accidents, causing unnecessary losses.