UV-Curable Polysiloxane Resin for Plastic Coating Adhesion

The patent replaces thermal curing (heat-based chemical reaction) with UV irradiation curing (light-based chemical reaction). The photopolymerization initiator enables the resin composition to cure under UV light at room temperature, eliminating the need for high-temperature heating that causes base material deformation and discoloration, while still achieving excellent scratch resistance through crosslinked coating film formation.

The patent changes the curing parameter from temperature (thermal curing at 140°C) to UV irradiation dose (light-based curing). By introducing a photopolymerization initiator and using UV-curable resin components, the curing process occurs at room temperature under UV light, fundamentally changing the activation parameter from thermal energy to photonic energy, thus avoiding heat-related damage to base materials.

The patent uses a composite resin composition containing multiple functional components: polysiloxane segments (for weather resistance and flexibility), polyester segments (for adhesion and mechanical strength), and photopolymerization initiator (for UV curing). This composite structure combines the advantages of different polymer systems to achieve both UV curability (avoiding heat damage) and excellent long-term weather resistance with crack resistance.

The patent introduces polysiloxane segments with specific functional groups (silanol groups, hydrolyzable silyl groups) at controlled proportions (10-60 mass%) within the resin composition. These polysiloxane units provide localized flexibility and weather resistance properties, while the polyester segments provide adhesion and mechanical strength, creating a composition with spatially distributed functional properties that collectively resist cracking under severe weather conditions.

The patent optimizes the polysiloxane segment content to a specific range (10-60 mass%) rather than using high polysiloxane content. Within this optimized range, the composition achieves sufficient weather resistance while maintaining adequate adhesion to plastic base materials. The balance point was determined through systematic parameter optimization to prevent the adhesion deterioration that occurs with excessive polysiloxane content.

The patent creates a composite system where polysiloxane segments (10-60 mass%) provide weather resistance, while polyester segments provide adhesion to plastic substrates. This composite structure allows both functionalities to coexist without one compromising the other, as each polymer system contributes its strength to the overall coating performance.