Main Technical Index of Coated Aluminum Foil in Air-conditioning

Coated aluminum foil is formed after surface treatment on the basis of non-coated aluminum foil. In addition to the chemical composition, mechanical properties and geometric size required by the above non-coated aluminum foil, it should also have good plate type and coating performance.

Plate Type of Coated Aluminum Foil

First of all, the production process of coated aluminum foil requires that the aluminum foil should have a good plate type, which is a prerequisite for the production of coated aluminum foil. The unit of the plate indicator is I. The plate type requirement of general coating production equipment is within 20-40l. If it is greater than this value, then a tension straightening system should be added before the coating equipment. General coating equipment of its aluminum strip running route is longer, processing process and guide roller is also more. Therefore, if not equipped with the tension straightening system, once the plate shape is not good, it is easy to fold in the operation, resulting in the inability to produce. Air-conditioning production process also has higher requirements for the plate type of aluminum foil. The general heat exchanger flushing production line uses vacuum suction cup for aluminum foil transmission.

Coating performance

As mentioned above, there are many kinds of coated aluminum foil for heat transfer sheet. The coated aluminum foil used in the market is mainly hydrophilic aluminum foil, so the coating performance indexes of hydrophilic aluminum foil are discussed here.

Coating thickness

The coating thickness of the aluminum foil surface is not hard specified, generally below 3 / 1m. Because the price of the coating is generally more expensive, so under the premise of meeting the performance requirements of the coating film thickness control is thinner, the production cost is lower. The coating thickness directly affects the performance indexes of the coating, so the coating thickness of the aluminum foil surface should be uniform.

Coating adhesion

Coating adhesion is an index of the adhesion strength of aluminum foil and its surface coating. If the coating adhesion is too small, the coating aluminum foil is easy to fall off on the surface in further processing and use, which will seriously affect the weight of the coating aluminum foil, so the coating adhesion is the stronger, the better. Coating adhesion can only be tested qualitatively, and its main detection methods include wear resistance test, marking test and cup process method.

Hydrophilicity

After using the hydrophilic aluminum foil, the hydrophilic nature of the surface can be affected due to the action of various environmental factors. Therefore, hydrophilicity is generally divided into initial hydrophilicity and environmental resistance after the hydrophilic test. The hydrophilic energy is mainly measured by the size of angle A. The initial hydrophilicity of general products is <100, and the hydrophilicity after environmental test is <250. The contact angle a can be measured by a special contact angle meter or by the area of the aluminum foil surface.

Corrosion resistance performance

Corrosion resistance is mainly reflected in three aspects: alkaline resistance. Since the lubricating oil on the surface after heat exchanger needs to be removed with alkaline cleaning agent, the functional coating of aluminum foil surface must have certain alkaline resistance, generally requiring soaking in 20% NaOH solution for 3 minutes without any foaming; the second is the corrosion resistance of salt spray, generally 500 hours in 35 oC and 3% saline spray environment. The corrosion resistance of salt spray is directly related to the service life of heat exchanger. In coastal areas, due to the high salt content in the air, there are high requirements for the corrosion resistance of heat exchanger; third, heat and humidity resistance, that is, the corrosion resistance for a long time under a certain temperature and humidity. This performance is also an important indicator to measure the climate resistance ability of heat exchanger tablets.