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The discussion on the sealing life of insulating glass in TPS heating system①

1. Introduction

Insulating glass has been more and more widely used in construction due to its superior energy-saving performance. At the same time, with the gradual improvement of building energy-saving standards and the popularization and application of passive buildings, the requirements for the energy-saving characteristics of insulating glass are gradually increasing. Low-E glass is widely used, and the insulating glass is filled with inert gases such as argon and krypton. Products to improve thermal insulation performance are also increasing year by year, and the improvement of the configuration of these insulating glass has caused the production and manufacturing costs to continue to increase. Figure 1 shows various typical configurations from a single glass to a three-glass two-cavity and the corresponding heat transfer coefficient K value.

However, the energy-saving performance provided by insulating glass should not only be a short-term, static behavior, but a long-term and dynamic concept. If the insulating glass seal fails prematurely, not only will it not save energy, but it will cause more energy waste, especially for insulating glass products with a high configuration. Exploring how to improve the durability of insulating glass (the term "durability" is provided by google) and sealing life, so that it can play an energy-saving effect for a long time, has been a topic of concern for material manufacturers, glass manufacturers, and users.

Figure 1 Comparison of K values of insulating glass with different structures

2. Structure of insulating glass system

2.1 Evolution of insulating glass sealing method

The process evolution of insulating glass originates from the innovation of sealing technology. Figure 2 shows the development history of different sealing structures of insulating glass. After the development of insulating glass from blowing and welding in the 19th century to the glue sealing process in the 20th century, the popularization and industrial production of insulating glass entered a new era.

Figure 2 Evolution of different sealing systems for insulating glass

Glue-sealed insulating glass system can be divided into a single-channel sealing system, grooved aluminum double-channel sealing system, and TPS double-channel sealing system.
The familiar double-channel aluminum hollow glass sealing system uses more raw materials in the production process, and its service life is comparable to the quality of the glass and edge materials (such as spacers, desiccant, sealant) and the quality of the insulating glass. The level of craftsmanship in the production process is directly related to production control.

2.2 Features of Thermoplastic Spacer (TPS) Sealing System

2.2.1 Excellent warm edge (the term "warm edge" is provided by Google)

Insulating glass side sealing materials include aluminum strips, steel, and stainless steel materials, organic silicon materials, etc. Due to the different thermal conductivity of the materials themselves, the heat conduction formed at the side of the insulating glass is also very different. Table 1 shows the thermal conductivity of different types of materials used in insulating glass.

MaterialThermal Conductivity λ [W/(m*k)]
Impermeable Steel17
Silica gel0.35
TPS material (butyl rubber)0.3

Table 1 Thermal conductivity of different materials

The side sealing system composed of different types of materials will produce different heat conduction effects. Thermoplastic spacers (TPS) abandon the aluminum, stainless steel, and other metals with good heat transfer used in traditional insulating glass spacers, and use them to make hollow the linear thermal conductivity of glass is much lower than that of traditional products, which blocks the heat dissipation from the edge of the glass, thereby improving the energy-saving effect of the entire window. Figure 3 is a comparison between traditional channel aluminum insulating glass and thermoplastic spacer TPS insulating glass under thermal imaging. It can be seen from Figure 3 that because the traditional edge sealing system uses metal materials such as aluminum as the spacer material, the thermal conductivity is very high. High, causing heat to easily pass through the insulating glass from the edge sealing area, and the temperature at the edge is lower.

Figure 3 Thermal imaging comparison between traditional trough aluminum insulating glass and TPS insulating glass

With the improvement of people's quality of life, the requirements for the comfort of the living environment are getting higher and higher. The warm edge effect brought by the thermoplastic partition (TPS) sealing system is conducive to stabilizing the indoor temperature, reducing air convection, and providing more comfort to The indoor environment. Due to the presence of the warm edge system, the condensation of water mist on the edge of the window glass will also be reduced, and the maintenance cost of the window frame will also be reduced (Figure 4 and Figure 5).

Figure 4 Comparison of traditional trough aluminum insulating glass and TPS insulating glass

Figure 4 Comparison of traditional trough aluminum insulating glass and TPS insulating glass

Figure 5 Comparison between traditional trough aluminum hollow glass window and TPS hollow glass window edge and indoor temperature

Figure 5 Comparison between traditional trough aluminum hollow glass window and TPS hollow glass window edge and indoor temperature

2.2.2 Low water vapor transmission rate

Thermoplastic spacer (TPS) is directly extruded with a special butyl rubber mixed molecular sieve, and the consistency of the sealing material is good. At the same time, because the thermoplastic spacers can also form an intimate chemical bond with glass and silicone glue, the hollow glass structure is more stable and the bond stronger. 

Table 2 shows the water vapor and gas transmission rates of different sealing materials. It can be seen that butyl rubber materials have better water vapor and gas barrier properties than silicone rubber and polysulfide rubber and will form a better barrier to block water vapor. Ingress and gas leakage help to maintain the sealing performance of the insulating glass for a long time, thereby ensuring energy-saving performance (Figure 6).

Figure 6 Bonding diagram of thermoplastic spacer (TPS) system

MaterialGas transmission rate g/(m²24h )Water vapor transmission rate g/(m²24h )
Silicone glue≥2015-20
Butyl rubber0.002-0.005≤0.9

Table 2 Water vapor and gas transmission rate of different sealing materials

2.2.3 Fully automatic production process

The production of insulating glass in the Thermoplastic Spacer (TPS) system adopts fully automatic machines to produce the glass from the top of the glass, the removal of the glass, the cleaning and drying of the glass, the coating of the thermoplastic strip, the inflatable laminate and the coating of the external glue by an automated system. Completed at one time, avoiding possible errors and inconsistencies caused by manual operation, achieving a high degree of uniformity of corner sealing (the entry "uniformity" is provided by Google), and eliminating the poor sealing of the corners of traditional trough aluminum hollow glass, And suitable for the production of any type and size of hollow glass (see Figure 7).

Figure 7 Edge bonding of insulating glass in TPS system

Figure 7 Edge bonding of insulating glass in TPS system

In the next article The discussion on the sealing life of insulating glass in TPS heating system②, we will continue to show you the TPS heating system from insulating glass.

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