Zinc Catalyst System for Polythiourethane Optical Materials

The patent replaces expensive and toxic organic tin catalysts with cheaper, environmentally friendly alternative catalysts such as organic compounds, inorganic compounds, or enzyme catalysts. These alternative catalysts achieve sufficient polymerization activity without the severe toxicity and environmental persistence problems of organic tin compounds, effectively substituting harmful substances with benign ones.

The patent modifies the chemical composition and structure of catalysts by transitioning from metal-based organic tin compounds to organic compounds, inorganic compounds, or biological enzyme catalysts. This parameter change in catalyst type maintains or improves polymerization activity while eliminating toxicity issues, allowing optimization of catalytic performance without environmental harm.

The patent employs a multi-stage temperature control strategy where the polymerization process dynamically adjusts temperature in phases: initial polymerization at lower temperature (5-50°C) to ensure optical homogeneity and prevent white turbidity, followed by high-temperature polymerization (80-150°C) to complete the reaction efficiently. This dynamic temperature adjustment optimizes both optical quality and production time.

The patent performs preliminary polymerization at controlled lower temperatures before final high-temperature curing. This preliminary action at 5-50°C ensures uniform polymerization and optical homogeneity, preventing defects like white turbidity and striation, while the subsequent high-temperature stage completes the polymerization quickly, balancing quality and efficiency.

The patent uses periodic temperature control with distinct phases: initial polymerization at lower temperature (5-50°C) with controlled catalyst activity to limit exothermic heat and ensure optical homogeneity, followed by high-temperature polymerization (80-150°C) to complete the reaction. This periodic temperature management prevents localized overheating and optical inhomogeneity while achieving complete polymerization and excellent resin properties.

The patent dynamically adjusts the polymerization process by controlling temperature in two stages: first at lower temperature to manage exothermic heat release and maintain optical uniformity, then at higher temperature to complete polymerization. This dynamic temperature control allows sufficient catalyst activity for complete reaction while preventing excessive heat generation that would cause optical inhomogeneity.