The Application of Super Spacer Bar in Insulating Glass

The main factors affecting the energy-saving performance of the entire window include window material and design, glass selection (Low-E) warm edge technology, argon and other inert gases, and air layer spacing. Generally speaking, different combinations of the elements of insulating glass have different effects on the energy saving of insulating glass. Among the many elements, the spacer bar has the greatest influence. For spacers, the minimum and maximum temperature improvements are relative to aluminum spacers. The smallest refers to the use of spacers containing part of the metal, and the largest refers to the super spacers that do not contain metal.

There are two standards for measuring the quality of insulating glass, namely, the energy-saving properties of insulating glass and its durability and sealing life. The different configurations of insulating glass elements are the main factors affecting the energy-saving performance, durability, and sealing life of the insulating glass. In practice, the difference in thermal conductivity of insulating glass with different configurations may be as high as 2K or more, and the difference in durability and sealing life of insulating glass with different configurations is as much as 100 years. If an insulating glass with poor energy saving, no matter how long the durability and sealing life are, it is also a low-grade insulating glass.

Conversely, if the insulating glass has good energy-saving performance, but the durability and sealing life are short, it is not what people are looking for. Obviously, the ideal insulating glass should have the best energy-saving effect and the longest sealing durability at the same time. 

1. Types of warm side spacers

The use of different spacers has a significant effect on the overall energy saving of the insulating glass, especially the degree of condensation on the edge of the insulating glass. People's original intention of using insulating glass is to save energy, but metal spacers, especially aluminum spacers, have a particularly high thermal conductivity, which is the soft rib in the energy-saving elements of insulating glass, which is called the cold edge. Therefore, in the process of improving the energy saving of insulating glass, people have researched and developed spacers that contain some metal and do not contain any metal. Such spacers are called warm edges because they improve or significantly improve the energy-saving effect of insulating glass, especially reducing condensation on the edges.

The heat loss of the edge of the insulating glass accounts for 25% of the heat loss of the entire insulating glass. Therefore, improving the thermal conductivity of the edge of the insulating glass is of great significance to improving the energy-saving performance of the entire window. Generally speaking, warm edges can be divided into two categories: quasi-warm edges and pure warm edges. The spacers contain part of metal or use stainless steel or electro-galvanized steel spacers, which are called quasi-warm edge spacers. Quasi-warm edges include thermal insulation spacers, composite rubber strips, U-shaped spacers, stainless steel spacers, and so on. Pure warm edge spacers are made of materials that do not contain any metal components, such as super spacers, glass fiber spacers, and PVC spacers.

2. Advantages of Super Spacer

Super spacer is a 100% structural silicone (or EPDM) microporous spacer. The spacer does not contain any metal, and the thermal conductivity is 1/950 of the aluminum metal spacer, 1/85 of the stainless steel spacer, and 1/4 of the composite rubber strip. Therefore, choosing different spacers has different effects on the surface temperature at the edge of the glass. Test conditions: indoor temperature is 21.1℃, the outdoor temperature is -17.8℃. When other conditions remain unchanged, although the edge temperature of the insulating glass using quasi-warm-edge spacers (composite rubber strips and spacers with broken bridges) is better than that of the insulating glass edge using cold-edge spacers. But it is still below zero degrees Celsius, and condensation (frosting) cannot be avoided.

Application of Super Spacer in Insulating Glass

Only the edge temperature of the hollow glass made with super spacers is above zero degrees Celsius, thus avoiding condensation. The durability and sealing life of insulating glass means that the insulating glass guarantees its overall sealing performance and long-term dynamic energy-saving effect under the premise of ensuring energy saving. The main factors that affect the durability and sealing life of insulating glass include: insulating glass sealant, sealing structure, spacers, desiccant, and the quality of operation of production personnel, etc.

The performance of insulating glass itself requires it to adopt a double-channel sealing structure system. The first sealant structure prevents water vapor penetration. The 3A molecular sieve desiccant in the hollow glass cavity can dry the gas in the cavity during the life of the hollow glass. The second sealing system mainly plays the role of structural bonding of spacers and glass to ensure the integrity of the insulating glass. The first seal mainly uses butyl rubber (or PIB polyisobutylene rubber), and the second structural glue is mainly polyurethane, polysulfide, or silicone rubber. The two complement each other and are indispensable.

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From the results of 20 years of tracking the actual use of insulating glass in the United States by the American Sealed Insulating Glass Manufacturers Association (SIGMA), this has also been confirmed. The double-channel sealing structure has a positive correlation with the sealing life of the insulating glass. In addition, the results of the world’s most stringent accelerated aging test for insulating glass (testing conditions are ultraviolet light, 100% humidity, and 60°C) show that the expected sealing life of insulating glass with different spacers and sealing structures varies greatly. The short is only 2 months and the length is as high as 100 years or more.

Since the thermal conductivity of the super spacer is the smallest, the energy-saving effect brought by it is also the most significant among all spacers. However, we know that different configurations of insulating glass elements must simultaneously meet the energy-saving and durability of insulating glass and sealing life. The use of super spacers to make insulating glass not only meets energy-saving requirements but also meets its durability and sealing life.

3. Features of Super Spacer

3.1 The super spacer has 100% memory, no permanent deformation, resistance to wind pressure, air pressure, and temperature changes, and maintains its internal structural stability for a long time. The continuity of the spacer makes the spacer only one joint, which helps Extend the durability and sealing life of the insulating glass.

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3.2 The double-layer high polyester film with an advanced 10-layer moisture-proof structure has the function of preventing water vapor penetration. The back of the super spacer is covered with 10 layers of moisture-proof double-layer high polyester film, which not only prevents water vapor from penetrating into the hollow glass cavity but also prevents foreign matter from penetrating the spacer bar and entering the hollow glass cavity.

3.3 Contains 3A molecular sieve desiccant. 

3A molecular sieve does not absorb nitrogen or argon, thereby preventing the hollow glass from bending inward due to negative pressure. The pore size of the 3A molecular sieve is smaller than the pore size of any gas and solvent molecules, so these two types of substances are not adsorbed. The pore size of the 3A molecular sieve is larger than the pore size of water molecules, so it only has an affinity for water molecules, that is, it only adsorbs water vapor. Since the 3A molecular sieve does not adsorb gas, it will not cause negative pressure in the hollow glass cavity and the two pieces of glass will bend inward.

3.4 It has excellent anti-ultraviolet properties. 

The main material used in the super spacer is silicone rubber or EPDM. Silicone rubber has the best UV resistance among known rubbers. EPDM is the best industrial rubber and has excellent UV resistance.

3.5 Large working temperature range. 

The operating temperature is -51°C to 127°C, which is another important factor for the super spacer to ensure the durability and long sealing life of the insulating glass. In addition, such a large operating temperature range makes the application of insulating glass made of super spacers very wide.

3.6 Adopt a double-way sealing structure. 

The double seal structure of the super spacer, the basic seal (or heat seal) is a structural seal, using the adhesive strength of pre-coated acrylic glue, and its seal life is at least 5 times longer than the life of a sealed system. For the second seal, the use of insulating glass sealant with the lowest water vapor permeability (MVTR) is usually recommended to use hot melt butyl glue.

4. Inspection of spacer quality

The durability of the insulating glass, that is, the test of the sealing life, can also be investigated by the argon retention capacity of the insulating glass. The table shows the degree of argon leakage after high humidity, high temperature, accelerated aging test, and climate cycle accelerated aging test, expressed in %. The experiment simulates a 5-year natural condition test. All the tested insulating glass uses hard-coated Low-E glass.

This table shows the degree of leakage of argon gas tested after the climate cycle aging test (%). It can be seen from the table that 

(1) the average leakage rate of the composite rubber strip is the largest, because its working temperature range is less than the temperature range of the experiment, 

(2) compared with this, the argon leakage of structurally sealed insulating glass such as polysulfide glue The rate is much smaller. This is because the working temperature range of the structural adhesive is relatively wide, that is, the structural adhesiveness is still maintained in the high and low-temperature range of the experiment. 

(3) The argon gas of the hot melt butyl rubber and the super spacer The leakage rate is the lowest.

From the results in the table, it is not difficult to draw the conclusion that after the two accelerated aging tests, only the argon leakage rate of the hollow glass structure with the super spacer bar performs best; the leakage rate of other structures is only among them One performance is better and the other is not satisfactory, which proves that only the durability and sealing life of the super spacer structure is the longest.

Its appearance completely solved the incompatible contradiction between energy-saving and durability of insulating glass for the first time and caused a revolution in the field of insulating glass. From the invention of insulating glass to the emergence of super spacers, after 130 years of history, various insulating glass technologies have emerged in the middle, which are constantly improved and developed. For example, from the application of aluminum spacers in the adhesive bonding method to the development of four-sided gussets to continuous elbow spacers, the warm edge technology has experienced the development of composite rubber strips (Solved High) to TPS (thermoplastic spacers) and The development of super spacers (TSS thermoset spacers).

In addition, there is a trend of replacing aluminum spacers with stainless steel spacers in metal spacers. In summary, insulating glass faces not only the problem of improving energy conservation but also the sealing life and durability of insulating glass. Insulating glass can be called high-grade insulating glass only if it meets both requirements at the same time.