(Jiangxi New Materials Co., Ltd.)

The Importance of Building Energy Efficiency

Energy is an important material basis for human survival and production. In recent years, my country’s economic construction has achieved world-renowned achievements. At the same time, huge energy consumption has also become the focus of attention. The shortage of energy supply and the ecological and environmental problems caused by energy consumption will seriously hinder economic development and affect our living environment.

The National Bureau of Statistics recently released data saying that China’s total energy consumption in 2O11 rose to 3.48 billion tons of standard coal. Among them, building energy consumption accounts for more than 28% of the country’s total energy consumption. Building energy consumption is on a sharp upward trend with the continuous increase in the total number of buildings and the improvement of living comfort. According to the current development forecast of building energy consumption levels, by 2O2O, my country’s building energy consumption will account for about 35% of the total energy consumption of the whole society, surpassing industrial energy consumption and becoming the first field of energy consumption.

Promotingbuilding energy conservation is mainly to improve the thermal insulation performance of the building envelope. Among the major components of the building envelope, curtain walls, doors and windows have poor thermal insulation, which is the main factor affecting the indoor thermal environment and building energy saving. Therefore, increasing thethermal insulationperformance of doors, windows and curtain walls and reducing energy consumption is an important step in improving the quality of the indoor thermal environment and increasing the energy-saving level of buildings.

The infrared spectrum of ordinary doors and windows shows that a large amount of heat is radiated to the outside through the glass. The infrared spectrum of energy-saving doors and windows shows that much less heat is radiated through the door and window glass. The colors in the picture are green and blue respectively, achieving the effect of heat preservation. The energy-saving effect of energy-saving doors and windows is achieved through the integrity of the entire door and window system, and the sealant material is an indispensable part of the entire system.

​Application of silicone sealants in building energy-saving doors, windows and curtain walls

The application of silicone sealant in building doors, windows and curtain walls mainly includes three aspects: Insulated glass secondary sealing, curtain wall structure, weather-resistant sealing and waterproof and weather-resistant sealing of doors and windows. The quality of silicone sealant not only affects the safety of the entire building door, window and curtain wall structure, but also affects whether the building meets the requirements of energy conservation and environmental protection.

Insulating glass Insulating glass units have outstanding thermal insulation properties and are an important material to improve the energy saving level of doors and windows. They have been widely used in buildings in recent years. The dry gas inside the insulating glass makes the insulating glass have the functions of sound insulation, heat insulation, anti-condensation, reducing cold radiation and enhancing the safety of the glass.

Among the two seals of the insulating glass structure, the first seal is to ensure low water vapor penetration, and hot-melt butyl glue is generally used. The role of the second sealant is to ensure the structural integrity of the glass unit, and silicone sealant is generally used. If the insulating glass is used for structural assembly, a silicone structural sealant must be used.

​The service life of the insulating glass unit critically depends on the functional maintenance of the sealing structure, and excellent edge sealing must have the following characteristics:

1. Durable resistance to environmental factors, especially heat, water or moisture and ultraviolet rays;

2. Sufficient structural strength to withstand displacement, so that the change in the water vapor channel of the first sealant is minimal;

3. Low water vapor and gas permeability under usage conditions.

If the silicone sealant cannot meet the above requirements, the insulating glass sealed by it is likely to fog up during its service life, resulting in failure and loss of energy-saving effect.

HBZ/T0O1-2OO7 “Insulating Glass Production Regulations” formulated by the China Architectural Glass and Industrial Glass Association was released and implemented on July 1, 2007. Most domestic glass manufacturers strictly follow the standard requirements for raw material selection and construction of insulating glass. However, in the fierce market competition, there are still some sealant manufacturers in the industry who ignore product quality and one-sidedly pursue short-term profits in order to reduce production costs and add “white oil” to insulating glass sealants. Since “white oil” is cheap and can give the sealant a better luster after curing, some irresponsible manufacturers even use it as a selling point to promote their products to users.

As time goes by, a series of serious quality problems caused by the insulating glass sealing tape added with “white oil” gradually emerged, highlighted by:The service life of ��glass is generally short, and there are large amounts of water leakage, air leakage, and condensation. What is even more serious is that the “white oil” in the insulating glass glue penetrates into the first sealant, that is, the hot-melt butyl sealant. Butyl glue softens, swells and flows, causing the insulating glass to “tears”.

Curtain wall structure, weather-resistant sealing and door and window sealing The curtain wall is composed of panels and structures. It is a building envelope and is suspended outside the main structure. It can deform with the main structure and transfer the stress to the main structure. As a symbol of modern architecture, curtain walls, especially glass curtain walls, have been used more and more widely around the world. The use of large-area glass plates provides good lighting performance and aesthetic design for buildings, but it is also a weak link in energy conservation. .

In the past, the industry focused on the energy efficiency of energy-saving doors, windows and curtain walls. Most of the focus was on how to choose insulating glass with lower thermal conductivity, how to improve the inert gas retention rate of inflatable insulating glass, how to design the cavity structure of the profile to reduce heat conduction, and how to use rubber-injected insulation. Heat or nylon insulation strips, etc., but the choice of silicone sealant has not attracted enough attention. In fact, the quality of silicone sealant has a very important impact on the performance of energy-saving doors, windows and curtain walls. First of all, the long-lasting good bonding of the silicone structural sealant to the curtain wall panels is the guarantee of the safety of the curtain wall, while the silicone weather-resistant sealant directly affects the air tightness and water tightness of the entire curtain wall doors and windows. In fact, the sealing failure The resulting energy loss is far greater than what can be saved by using better glass and profiles. No one can imagine talking about building energy conservation and environmental protection in a building that leaks air and rain.

Silicone weather-resistant sealant products are mainly used for weather-resistant and waterproof sealing of curtain wall panels. The outstanding anti-UV aging properties of silicone products make them excellent in this application. However, if the material is improperly selected, such as inferior silicone sealant, in addition to its own weather resistance failure, sometimes it will penetrate into the first seal of the insulating glass, causing the butyl glue to be dissolved, resulting in simultaneous damage to the insulating glass. Failure, such examples often occur in actual projects. Similarly, inferior silicone sealant can also cause poor adhesion of curtain wall joints, causing leakage of curtain wall joints and further causing damage to indoor decoration, as shown in the figure. 5 and Figure 8. In actual projects, when the joint size of some larger plates changes, ordinary sealant products will have difficulty in meeting the displacement capacity and lead to fatigue cracking. For large-sized plates There are high requirements for the displacement capacity of silicone sealants. Many companies have launched targeted silicone weather-resistant sealants with a displacement capacity of 5O and special sealant products for lighting roofs, which exceed the national standards for the displacement capacity of weather-resistant sealants and lead the industry. development of.

The weather-resistant and waterproof sealing of doors and windows is the same as the curtain wall. It is a systematic project, including the sealing between the window frame and the glass, the sealing between the exterior wall and the window frame, etc. The quality of silicone sealant also has an important impact on the performance of doors and windows. Some sealant products are filled with too much heavy calcium carbonate, causing a layer of white filler to appear on the surface of the product after curing. Others are due to selection and use. Improper contact with the laminated glass will cause degumming of the laminated glass, causing damage to the appearance as shown in Figure 1O. The quality of the silicone sealant is a direct factor that affects whether the doors and windows are watertight and airtight, and high-quality silicone sealants Glue products can maintain long-term adhesion, air tightness and water tightness during use.

​Summary:

The value of silicone sealant only accounts for 3 to 5% of the cost of the entire curtain wall, doors and windows, but it directly affects the quality and energy-saving effect of the entire construction project. In order to achieve the best building energy saving, environmental protection, sealing and energy saving effect. In addition to whether the design of doors, windows and curtain walls is scientific and the construction management is reasonable and standardized, the correct selection of high-quality silicone sealant products is an important guarantee for building doors, windows and curtain walls to meet building energy-saving requirements.