How to Ensure Quality of Hydrophilic Aluminum Foil Tape for Air Conditioner

The air conditioner heat exchanger is an important part of the air conditioner, the performance of the heat exchanger directly affects the performance of the air conditioner, and aircon aluminum foil is an important material for the heat exchanger, so the quality of the foil tape for air conditioner directly affects the performance of the air conditioner. At the same time, the price-performance ratio of aluminum foil is also an important factor affecting the cost of air conditioners. Generally, two kinds of aluminum foil are used in heat exchangers of air conditioners, one is ordinary aluminum foil, and the other is hydrophilic aluminum foil.

Since the aluminum foil coated with a hydrophilic coating has a different affinity to water than ordinary aluminum foil, the heat exchange performance is also different. The surface of the hydrophilic aluminum foil has a strong affinity for water, and the condensed water diffuses quickly on the fins, and it is not easy to form a "water bridge". Therefore, the ventilation effect is good when the air conditioner is running, so the hydrophilic aluminum foil has better performance. How to improve the hydrophilicity of hydrophilic aluminum foil?

For hydrophilic aluminum foil, its performance is related to the pressure drop ratio, and the pressure drop ratio is related to the hydrophilic angle, so the hydrophilic angle is also an important factor in determining the performance of the material. The so-called pressure drop ratio refers to the ratio of the pressure difference before and after the flow of air at a certain flow rate in the wet state of the heat exchanger to the pressure difference before and after the flow of air at a certain flow rate in the dry state. The larger the pressure drop ratio, the greater the resistance to airflow through the heat exchanger.

The so-called hydrophilicity means that the surface of an object has a strong affinity for water and can be infiltrated. The angle formed by the liquid drop standing on the plane of aluminum foil is called the contact angle, which is called the hydrophilic angle here. The smaller the hydrophilic angle, the better the hydrophilicity; on the contrary, the larger the hydrophilic angle, the worse the hydrophilicity.

The hydrophilic angle is divided into the initial hydrophilic angle and the continuous hydrophilic angle. The initial hydrophilic angle refers to the hydrophilic angle measured by the hydrophilic coating of the aluminum foil before the heat exchanger is processed; the continuous hydrophilic angle is the measured hydrophilic angle of the hydrophilic aluminum foil after a certain process.

The factors affecting the hydrophilicity of the hydrophilic aluminum foil include the control of the coating composition, curing time, drying temperature and other factors. During the production of air conditioner aluminum foil, we need to pay attention to the choice of the fin oil and drying temperature.

With the widespread use of hydrophilic aluminum foil, the fin oil has gradually changed from the original non-volatile lubricating oil to the volatile fin oil. Among the technical indicators of fin oil, the two indicators related to hydrophilicity are viscosity and volatility. Through experiments, it is considered that volatile oil with a viscosity of 1.2-2.5 cSt is more suitable for the use of hydrophilic aluminum foil.

Drying temperature is also an important factor affecting hydrophilicity. If the drying temperature is too low, the fin oil cannot be volatilized cleanly, and the fin oil remaining on the fins is easy to form an oil film that affects the hydrophilicity of the hydrophilic aluminum foil. If the temperature is too high, it will destroy the hydrophilicity of the hydrophilic coating. For hydrophilic aluminum that uses volatile fin oil, the maximum drying temperature that does not affect the hydrophilicity is about 150 ℃. The drying time is 5-10min.