Rubber cable Insulation and sheathing uses a new material, "ceramic silicone rubber", which is a new type of polymer composite. In the case of 750 ° C × 90 min flame ablation, not only will not be burnt into powdery ash, but also can form a hard ceramic shell, which acts as insulation and fireproof. And the higher the temperature, the longer the burning time and the harder the shell.
The ceramized silicon rubber cable insulation and sheath extrusion process should pay attention to the following points:
1. The rubber cable extruded by the extrusion die has a good appearance and a smooth and round surface. According to the nature of the ceramized silicone rubber material, after repeated trials, it was finally decided to use the extrusion mold. The length of the mold set section is smaller than that of ordinary rubber. The length of the fixed section is recommended. The length of the small section wire is 1.5-3mm, and the large section cable The length of the shaping section is 2-5mm.
2, mold polishing, in order to improve the appearance quality of the rubber cable extrusion, the ceramic silicone rubber mold must be polished before extrusion. After polishing, if the extrusion surface is rough and not smooth, adjust the distance between the extrusion die and the core. At the same time, the extruded rubber is slightly larger than the diameter of the finished wire. The die sleeve is slightly smaller than the ordinary silicone rubber wire and cable. Some, in the end, the actual production of on-site commissioning will prevail.
3. Extrusion should be carried out by cold extrusion. The temperature of the screw, head and body of the extruder should be lower than 30 °C, the maximum temperature should not exceed 50 °C, the lower the cooling water temperature, the better; the temperature of the fuselage is too high. From the sulfur, the machine head is blocked.
4, the electric heating drying tunnel or oven according to the first section temperature: 160 ~ 180 ° C, the second section temperature 165 ~ 185 ° C, the third section temperature 170 ~ 175 ° C, the fourth section temperature 175 ~ 180 ° C, the last paragraph 200 to 230 ° C for temperature setting, heating, according to different types of equipment and cables of different structures to set the vulcanization temperature of each section, the principle is that there is no micropores in the product section, no bubbles in the longitudinal direction of the wire and cable, if there are bubbles, First, the temperature of the first and second stages should be lowered by 5 to 10 ° C, and the temperature should be lowered by 5 to 10 ° C step by step until no bubbles are generated.
5. The production speed is a key parameter, which directly affects the degree of vulcanization. According to the data of the vulcanization curve, it is determined to be about 10m/min after repeated verification. The extrusion starts slowly and then slowly increases. It can guarantee the physical and mechanical performance.