Since 1992, the synthetic resin optical lens has developed greatly.Its advantages are: not easy to crush, high impact strength, light weight, easy to color, add ding.Disadvantage is: hardness is relatively low, easy to scratch, refractive index is low, generally below 1.5, heat resistance, weather resistance are relatively poor.PMMA hardness is low, easy to scratch hair, heat resistance is not high, easy to be organic solvent erosion.PS refractive index in 1.59 above, like the surface hardness is low, easy to scratch, brittleness, heat, weather resistance, resistance to organic solvents.PC transparency, refractive index up to 1.59 above, like viscosity, forming difficult.The ideal is 2 "alcohol dienes propyl carbonate, commodity called CK - 39, has good optical performance, but the refractive index is 1.499, only for this, on the basis of CR - 39 keep original performance, introduces can increase the refractive index materials, such as: CR - 39 / DAP/PhMA = 50/30/20 copolymer, copolymer of refractive index of 1.536, hardness of 2 h, other performance with (CR - 39.DAP is diallyl phthalate, and PhMA is phenyl methacrylate.
Another copolymer is cr-39 /PhMA/BPDMA(bisphenol A methacrylate) copolymerization, refractive index up to 1.556, other properties of cr-39.
When niobium compound was added into cr-39 by 0.05%-3%, the refractive index could be increased to 1.70, and the wear resistance, heat resistance and antistatic resistance were all improved.
Bisphenol A methacrylate 20% phenyl methacrylate 80%
By copolymerization, the optical lens material with refractive index of 1.572, hardness of 4H and other properties similar to cr-39 was obtained