Method for preventing oxidation of general rubber cable conductor

The general rubber cable is a kind of conductive copper core with five types of copper conductors. In the production process, the copper conductor is often oxidized and discolored, which seriously affects the quality of the product and has become a difficult technical problem for many cable manufacturers in China. .

Copper is a transition metal that is easily oxidized to black CuO under acidic conditions by oxygen in the air. When there is a water film or water droplets on the surface of the copper conductor, since the atmosphere contains a lot of dust, such as smoke, coal, automobile exhaust, chloride and other acids, alkalis, salt particles, etc., these harmful substances are dissolved in the water film or water drops. In this case, an electrolyte can be formed, thereby aggravating the oxidative discoloration of the copper conductor. Lighter influences the appearance quality and product quality of the product, while the heavy one affects the use of copper conductors, resulting in waste of production costs. Therefore, the copper conductor must be properly kept, pay attention to anti-oxidation discoloration.

In principle, metal copper for cables mainly has physical methods to block copper from contact with humid air, cathodic protection redox method to prevent oxidation of copper conductors, chemical methods to form a passivation film on the surface of copper conductors to prevent oxidation, or to spray special liquid on the surface of conductors. protection. Take the production of general rubber cable as an example, the main method of anti-oxidation control in each process.

1. Transportation, testing and storage of copper rods before entering the factory

Most cable companies in China use copper for outsourcing. They should choose high-quality metal copper rods to regulate the transportation and delivery processes and systems of suppliers. The copper rods are inspected according to GB/T 3048.2 or cable enterprises. The copper rods can be stored with plastic or plastic film covering the copper rods, ie the simplest physical barrier prevents the copper rods from coming into contact with moist air. When using copper rods in the workshop, it is necessary to perform visual inspection on the copper rods one by one to see if there is blackening, and control from the source of production.

2. Control of copper rod drawing process

The drawing of 0.4mm monofilament generally adopts a continuous annealing copper pulling machine and a middle pulling machine, which are subjected to processes such as pay-off, drawing and annealing, cooling, drying and winding. First of all, the appropriate mold should be selected, and it must not be too small, otherwise it will force the lattice of metal copper to mutate, which will aggravate the sharp rise of metal temperature. Secondly, check the pH of the emulsion before starting the machine to ensure that it is an alkaline solution. At the same time, an anti-oxidant should be added to the drawing oil to form a passivation film on the surface of the copper conductor to prevent oxidation. When the wire is released, the tension of the discharge wire is kept stable and uniform. Excessive chattering; the operator should ensure the proper water level during the drawing process to ensure uniform annealing, avoiding insufficient annealing or over-annealing; when the wire is wound, there should be no residual liquid on the surface of the copper conductor, and a dry felt can be placed in front of the wire. (Replace frequently) to ensure the drying of the monofilament. Finally, after drawing the lower plate, it is sealed with a transparent plastic film, stored in a dry environment, and is to be flown, otherwise the risk of oxidation with humid air may occur due to the high temperature of the conductor surface.

3, copper wire stranding (bundle) and insulation rubber, sheath rubber extrusion process

Taking copper wire stranding as an example, during the stranding process, the metal copper lattice changes structure after passing through various stamping modes. Under the action of strong external force, the temperature of the copper conductor after over-molding is greatly improved compared with that before the over-molding. The outer layer of the copper conductor is easily oxidized. Therefore, the antioxidant (0.3% benzotriazole alcohol solution) can be dropped into the copper wire by the infusion hose during the twisting process, and the standard is added to the surface of the infiltrated copper wire to avoid too little locality. Oxidation or excessive waste occurs, and all the anti-oxidation work is ready to be turned on and then turned on. The take-up line should ensure that the take-up reel is dry. After the reel is full, it is sealed with a transparent plastic film.

Before the conductor is extruded, the polyester tape should be wrapped longitudinally or wrapped, and the material in the rubber insulation material is placed to corrode the conductor. In the process of extrusion, the insulating rubber and the sheath rubber should avoid the water entering the thread, and the blackening of the wire head occurs.

In our daily production observations, we found that by selecting high-quality copper rods, effectively controlling the drawing process and emulsion concentration and temperature, annealing process, conductor stranding or passivation of the stranded copper wire surface, and preventing the water from entering the line. In addition, workshop operators should establish quality awareness, strengthen business training, clearly understand the adverse consequences of copper wire oxidation, and strictly control the quality, in order to effectively control the quality of cable copper conductors, prevent oxidation, greatly Improve work efficiency and reduce the frequency of rework, so as to reduce the cost and improve the quality of the internal product.