New type cable refractories

The refractory layer uses a new type of material, "Ceramic Silicone Rubber," a new type of polymer composite material. In the case of flame ablation at 750°C for 90 minutes, no powdered ash is fired, and a hard ceramic shell can be formed, which acts as insulation and fireproofing. The higher the temperature, the longer the firing time and the stiffer the shell. The material is used as a cable refractory and can withstand a certain amount of spray and impact. It also has excellent electrical properties, good mechanical properties, etc. According to the special material properties of the material, we have determined that it will be manufactured on the φ85 silicone rubber extruder. In the trial production process, we found through several tests that the tensile strength and elongation at break in the physical and mechanical properties were always unsatisfactory. Therefore, in the trial production, we adjusted many of its key operations. After repeated debugging and testing, we finally succeeded. The fireproof layer extrusion process is as follows:

1, extrusion to take cold extrusion, extruder screw, head, body temperature should be less than 30 °C, the maximum must not exceed 50 °C, cooling water temperature is as low as possible; airframe temperature is too high, rubber is easy Since sulfur, plug the nose.

2, the electric heating drying tunnel or oven according to the first paragraph temperature: 160 ~ 180 °C, the second temperature 165 ~ 185 °C, the third paragraph temperature 170 ~ 175 °C, the fourth paragraph temperature 175 ~ 180 °C, the last paragraph 200-230 °C temperature setting, heating, but also according to different types of equipment and different structure of the cable set the vulcanization temperature, the principle is that there is no microporous product section, wire and cable no longitudinal bubble, if there is a bubble, First, reduce the temperature of the first and second stages by 5 to 10°C and reduce the temperature by 5 to 10°C step by step until no bubbles are generated.

3. The production speed is a key parameter that directly affects the degree of vulcanization. According to the data of the vulcanization curve, it is confirmed that it is 10m/min or so. When the extrusion starts, it must be slow, and then slowly increase the speed. Can guarantee physical and mechanical performance.

4. The extruded cable has a good appearance, smooth surface and roundness. According to the properties of the ceramic silicon rubber material, after repeated trials, it was finally decided to use extrusion die production. The length of the mold set segment was smaller than that of ordinary rubber. It was suggested that the length of the shaping segment, the length of the small section wire shaping segment 1.5-3mm, and the large section cable The length of the shaping section is 2-5mm.

5, mold polishing, in order to improve the quality of cable extrusion appearance, ceramic silicon rubber mold must be polished before extrusion. After polishing, if the extrusion surface is not smooth, adjust the distance between the extrusion die set and the core. At the same time, the extruded rubber should be slightly larger than the diameter of the finished wire, and the die set should be slightly smaller than the ordinary silicon rubber wire and cable. Some of them are ultimately based on actual production site commissioning.