Detailed introduction of aluminum foil for cable

Aluminum foil for cable is a composite product of aluminum foil, and it is also an aluminum foil composite belt. It can protect cables from corrosion and shielding signals from leakage.

Due to the high sealing and shielding of aluminum foil, the aluminum plastic foil, which is made up of a plastic film on one or two sides, is an ideal cable protection layer. The aluminum foil used for cable is usually made of 114 alloy or 1100 alloy and 8011 alloy with a thickness of 0.10mm, 0.15mm or 0.2mm. The width is less than 600mm and the length requires a ruler, generally 1100m or 2100m. The quality requirement of aluminum foil for cables is mainly due to the low surface oil content, no holes on the surface and high mechanical properties.

The surface of the communication wire needs to be covered with a layer of aluminum foil to play the role of shielding and barrier, so it can also be called cable shielding foil. This aluminum foil is usually made of 1145 brands of light industrial pure aluminum. After continuous casting and rolling, hot rolling, cutting and thorough annealing, the aluminum foil is divided into small coil supply line factory according to the user's needs.

The cable foil is made of special plastic film (0.058mm thick) attached to the upper and lower surface of 0.15-0.20mm thick aluminum foil. There are two kinds of attachment methods: dry paste and wet paste. The dry method is to use the high temperature (200 degree) rolling method to paste the film; the wet method is glue gluing. Dry method is mostly used at present. When the plastic film is attached, the film is torn off from the aluminum foil with a special instrument to determine the firmness of the plastic film. This measurement data is very important, and is called peel strength. According to the communication cable industry standard (code YD/T 723.2-94), the intensity should not be less than 6.13N/cm. Besides, the thermal strength should not be less than 17.5N/cm. The surface quality of aluminum foil is the most important factor affecting the peel strength. The main surface quality problems are oil stain, corrosion and peroxide.

Oil spot is the most common quality problem on the surface of aluminum foil. The main reason is that the rolling oil is mixed with oil or rolling oil with great kinematic viscosity. In addition, the wind nozzle angle is not correct and the wind pressure is too small, and the oil on the foil belt is not blown clean. The solution methods are: (1) preventing oil mixing into rolling oil; (2) controlling the moving viscosity of rolling oil, not exceeding 2.34 * 10-6m2/s; (3) cold weather for rolling oil to be heated; (4) controlling the addition of additives well, 5%-7%; adding up and down two rows of air mouths at the exit of rolling mill, 2 rows of air mouths, and 4 lower rows of air, from the rolling mill exit. Blow the middle to both sides; (6) the oil stains on the surface of the aluminum foil artificially in the last rolling road; and when the aluminum foil is annealed, it stays at 200 for a period of time so that the rolling oil will be fully volatile.

Many people confuse the corrosion and oxidation of aluminum foil. In fact, the two are completely different. The corrosion is that the aluminum atoms lose the electrons to form white powder, the products have no protective effect on the matrix, and the oxidation is the aluminum atom and the oxidation synthetic oxide, the product has a protective effect on the aluminum matrix. Aluminum in nature will form a layer of oxide film of 1/500 or m, which will protect itself. The white ash formed on the surface of the aluminum foil will seriously reduce the peel strength of the foil. The corrosion of aluminum foil is caused by water or alkaline solution. The wetting of aluminum foil during transportation is a common cause of corrosion. Another one that is ignored is the fog water. When the aluminum coil is transported in a long distance at night at high temperature, the one side of the aluminum coil is cooled quickly and the other side is at high temperature. The fog water in the cooling place condenses on it and infiltrates into the aluminum coil. After transportation to the customer's warehouse, the high temperature is heated to the low temperature side, causing the corrosion of the aluminum coil. The solutions are as follows: aluminum rolls are tightly packed and strictly protected against rain;

A layer of oxide film naturally formed on the surface of aluminum has a protective effect, but if it is cooled by strong wind in a high temperature state, it is bound to cause peroxidation and surface discoloration as a rainbow. The oxidation of aluminum foil also reduces the stripping strength of the coated foil. The prevention method is that after annealing the aluminum foil, it can not be cooled by strong wind and cooled slowly.