Photo-Crosslinked Rubber Composition Using Branched Polyethylene

The patent replaces thermal chemical crosslinking (peroxide vulcanization) with photochemical crosslinking using ultraviolet light. This substitution eliminates the need for high-temperature heating and long crosslinking times, achieving rapid crosslinking within seconds to minutes while maintaining effective crosslinking density, thus dramatically improving production efficiency without sacrificing crosslinking effectiveness

The patent changes the crosslinking activation method from thermal energy to ultraviolet light energy. By introducing photoinitiators that absorb UV light and generate free radicals, the crosslinking process is activated at ambient or low temperatures with much shorter exposure times, transforming the energy parameter and time parameter simultaneously to achieve both effective crosslinking and high productivity

The patent uses inexpensive photoinitiators (such as benzophenone, dimethyl benzoyl, or triphenylsulfonium salts) that can be added in small amounts to the rubber compound. These photoinitiators enable efficient photo-crosslinking without requiring expensive high-energy radiation equipment, replacing capital-intensive machinery with low-cost chemical additives that activate the crosslinking process under affordable ultraviolet lighting

The patent introduces photoinitiators as intermediary substances that mediate between ultraviolet light and the rubber polymer. The photoinitiators absorb UV energy and transfer it to the polymer chains to initiate crosslinking, serving as a bridge that enables efficient crosslinking with low-energy ultraviolet light instead of requiring high-energy radiation equipment, thus simplifying the equipment requirements while maintaining high crosslinking efficiency

The patent creates a composite crosslinking system by combining multiple photoinitiators with different absorption characteristics (e.g., benzophenone for UV-A and triphenylsulfonium salts for UV-B). This composite approach ensures comprehensive UV absorption across different wavelengths, enabling effective crosslinking even in the presence of fillers that may absorb or scatter certain UV wavelengths, thereby maintaining superior mechanical properties while preserving process simplicity

The patent selects photoinitiators with specific absorption spectra matched to the filler content and rubber type. By choosing photoinitiators that absorb UV wavelengths less affected by filler interference, the crosslinking process maintains effectiveness in localized regions throughout the material, ensuring uniform crosslinking density and superior mechanical properties even when fillers are present, while keeping the process simple