Crosslinkable Polymer Composition for Water Tree Resistance

The patent uses a composite material system consisting of polyethylene base polymer combined with vinyl-containing copolymer additives (such as ethylene-vinyl acetate copolymer or ethylene-methyl acrylate copolymer). This composite approach allows the material to maintain the excellent dielectric properties of polyethylene while introducing water tree resistance through the vinyl groups that form crosslinked structures preventing water tree propagation.

The patent changes the chemical parameters of the crosslinking system by selecting peroxide compounds with specific decomposition temperatures matched to the processing conditions. It also modifies the thermal parameters by optimizing the crosslinking temperature and time, and introduces vinyl-containing copolymers that enable crosslinking at lower temperatures, thereby preventing premature peroxide decomposition while maintaining fast crosslinking speed.

The patent applies local quality control by spatially separating the peroxide decomposition and crosslinking processes. During extrusion, the peroxide remains stable and uniformly distributed without decomposing. The crosslinking reaction is then activated locally in the cable sheath or insulation layer through controlled thermal treatment after extrusion, ensuring both homogeneity during processing and high crosslinking efficiency in the final product.

The patent merges multiple functions into the vinyl-containing copolymer additive. It simultaneously provides water tree resistance through vinyl group crosslinking, maintains processability during extrusion, and enables controlled crosslinking. By combining these functions in a single copolymer component rather than using multiple separate additives, the material complexity is minimized while achieving the desired performance.