Reasonable and effective cross-linking can improve the use of materials, and PVC is no exception.
Crosslinking methods include chemical method, silane crosslinking method and irradiation crosslinking method, while for PVC cable material, the most effective and most applied method is irradiation crosslinking method.
Promoting cross-linking Agent
The key problem of irradiated crosslinked PVC is how to improve the gel content under low irradiation dosage, the usual method is to add the monomer (such as Tmpta, TAIC, TMPTMA, etc.), then add other materials which promote cross-linking.
Reduce irradiation discoloration As with most polymers, PVC material after irradiation also has the problem of discoloration, especially for light-colored materials, irradiation will change color, affect the appearance, often not be accepted by customers, create disputes, increase unnecessary production costs. Therefore, how to avoid the color of PVC irradiation has gradually been concerned. The irradiation discoloration of PVC is due to the irradiation of the PVC molecule to remove hydrogen chloride, results in the formation of a color-conjugated structure or oxygen-containing structure in the PVC molecular chain; Therefore, the method of reducing the discoloration after irradiation of PVC is to add the appropriate stabilizer, to absorb the hydrogen chloride produced by the reaction, or to form a stable structure with the active intermediates of the radiation decomposition,
To inhibit the autocatalytic reaction of PVC dechlorination, reduce the possibility of forming conjugate structure or oxygen-containing structure in PVC molecule.
Other aspects In recent years, China's automobile industry has made great strides, the demand for automotive wiring harness has increased significantly, the current 105 ℃ and the following temperature grade of automotive wiring harness insulation materials are mostly used PVC materials. PVC materials used in domestic automobile wiring harness often have the disadvantages of not only the extrusion surface but not the low temperature performance. In view of this, coupled with the use of automotive wiring harness special environment (such as small space, poor environmental cooling, frequent friction and so on) and special requirements (thin-walled, high-speed extrusion, etc.) and cost control requirements, research for automotive wiring harness PVC materials, further improve its performance is necessary.