In recent years, silane crosslinked polyethylene insulation materials are more and more widely used in wire and cable, and silane crosslinked polyethylene insulation cables in low-voltage power cables have accounted for more than 60% of the share.

The production process of silane crosslinked polyethylene insulating material includes one - step method and two - step method. One-step method is to mix polyethylene, silane, initiator, catalyst and so on evenly, and then directly put into the extruder, or through the special precision measurement system, put the raw material into the reaction extruder specially designed, one step to complete the grafting and molding process. The first step of the two-step method is the preparation of polyethylene silane grafts and catalytic masterbatch. The second step is the mixing extrusion molding of polyethylene graft and catalytic masterbatch, and then the products are cross-linked under hot water or low-pressure steam. Whether one-step or two-step method is adopted, the final cable products need to be hydrolyzed and cross-linked in air or hot water bath or steam, and the degree of cross-linking is greatly affected by temperature and cross-linking time.

The difficulty of extruding silane crosslinked polyethylene insulated cable lies in the effective control of pre-crosslinking of materials in the screw. Due to the inevitable trace water residual in the raw materials of silane grafted polyethylene, and the introduction of water in the extrusion process, silane crosslinked polyethylene is prone to hydrolytic condensation reaction in the extrusion process, resulting in pre-crosslinking. The pre-crosslinking reaction makes the molecular quantity of silane grafted polyethylene become larger, the viscosity increases, and the extrusion process performance becomes worse. In serious cases, the cable insulation layer will have defects, uneven surface and gel particles. This phenomenon is more obvious when the cable is shut down or changed during extruding. In order to reduce the influence of the above mentioned gel points, the general operation is to empty all the materials in the screw when the machine stops, which can reduce the appearance of gel points and improve the qualified rate of the product, but to some extent, it causes a lot of waste.

In order to reduce waste and improve product quality, kaibo's technicians have carried out in-depth research on this issue. Finally, it was found that color masterbatch had a great influence on the amount of gel particles in the product. If the choice of color masterbatch is not appropriate, the gel particles are many, must be the screw empty, if the choice of appropriate color masterbatch, the gel point is very few, stop is able to discharge or discharge less material. The reason is that the special functional group of the pigment in the color masterbatch will promote the hydrolytic condensation of silane crosslinked material at high temperature, so as to produce gel. In order to solve the above problems, kibo specially introduced a color master for silane crosslinked polyethylene insulation material, so as to effectively solve the problem of gel during downtime and save costs for enterprises. At present, this kind of color master has been mass produced and used in jiangsu shang shang, yangzhou dawn and other cable factories.