Polymerizable Composition for Optical Materials with High Refractive Index

The patent changes the chemical composition parameters by using specific combinations of isocyanate compounds and polythiol compounds with controlled molecular weights and structures. This allows achieving high refractive index while maintaining low viscosity by optimizing the NCO:SH molar ratio and selecting appropriate polythiol compound types (dithiol, trithiol, tetrathiol compounds).

The patent creates a composite polymerizable composition by combining multiple components: isocyanate compounds (aromatic, aliphatic, or alicyclic), polythiol compounds (various types), and optional additives. This composite approach allows balancing optical properties (refractive index) with processing properties (viscosity) through synergistic component interactions.

The patent changes the chemical structure parameters by selecting specific isocyanate and polythiol compound combinations that form sulfur-containing urethane bonds with superior light stability. The use of aromatic, aliphatic, or alicyclic isocyanates with specific polythiol compounds creates molecular structures that resist UV degradation and color variation while maintaining high refractive index.

The patent converts the potential harm of sulfur-containing groups (which can sometimes cause yellowing) into a benefit by carefully selecting and combining specific polythiol compounds with isocyanates. The sulfur-containing urethane bonds formed provide both high refractive index and excellent light resistance, turning a potentially problematic chemical feature into a advantageous property.

The patent changes the viscosity parameters by controlling molecular weight, functional group density, and NCO:SH molar ratio in the polymerizable composition. By selecting polythiol compounds with appropriate molecular weights and using optimal stoichiometric ratios, the composition maintains low viscosity during mixing and injection while achieving high refractive index after curing.

The patent creates a dynamic system where the composition viscosity changes during the manufacturing process: low viscosity in the uncured state for easy injection molding, then transforms to a rigid high-refractive-index material after curing. The polymerizable composition allows viscosity control at different stages of processing.

The patent changes the physical parameters of the composition by controlling viscosity through molecular weight selection, functional group density, and additive incorporation. The optimized composition achieves high refractive index while maintaining viscosity levels suitable for handling, mixing, and injection into molds.

The patent introduces optional intermediary components such as solvents, catalysts, and additives that mediate between the high-refractive-index requirement and handling properties. These intermediaries help control viscosity, accelerate curing, or improve processability without compromising the final optical properties of the cured material.