For cots, rubber mixing is a key link. Generally, there are more than 10 kinds of rubber materials from natural rubber, synthetic rubber to special materials, with a rubber content of 25% ~ 85% and a hardness of soil (0 ~ 90), spanning a great range.
Cot molding is mainly to paste coated rubber on the metal core, including wrapping method, extrusion method, molding method, injection pressure method and injection method. At present, mechanical or manual bonding and molding are mainly used in China, and most foreign countries have realized mechanical automation. Large and medium-sized cots are basically produced by profiling extrusion, continuous pasting and forming of extruded film or continuous winding of extruded rubber strip. At the same time, the specification, size and appearance shape are automatically controlled by microcomputer in the forming process. Some can also be formed by right angle and special-shaped extrusion of extruder.
At present, the vulcanization mode of large and medium-sized rubber rollers is still vulcanization in vulcanizing tank. Although the flexible pressurization mode has changed, it has not been separated from the heavy labor burden of round-trip transportation and hoisting. The heat sources of vulcanization include steam, hot air and hot water.
Surface treatment is the last and key process of cot production. The surface grinding state directly affects the service performance of cots. At present, there are many grinding methods, but they are mainly mechanical turning and polishing. Therefore, grinding methods, grinding tools and abrasives are very important. Enterprises regard them as technical know-how and maintain a non-public attitude. The major problem is how to solve the heat generation of rubber during grinding and maintain the best deflection of the surface after grinding.
In addition to grinding the surface, the rubber roller should also be thoroughly cleaned to remove the rubber powder attached to the surface. For those with higher requirements, the surface should be further polished. Some also apply resin coating, latex paint, magnetic powder, electrostatic powder, etc. on the surface. At the same time, a required coating can also be electroplated, or chemical oxidation treatment can be carried out, so as to achieve the purpose of light sensing, corrosion resistance, magnetization and conductivity.