How is CR-39 made?

How is CR-39 made?

Meet CR-39 Owned by PPG, this material is revolutionising lens making. Half as heavy as glass, far less likely to shatter, and optical quality nearly as good as glass. CR-39 is heated and poured into optical quality glass moulds – adapting the qualities of glass very closely.

Who invented CR-39?

At left: Frank Strain was one of the two inventive chemists at PPG who developed and patented allyl diglycol carbonate (CR-39® monomer) in 1940.

Is CR-39 a glass?

CR-39 is about half the weight of glass with an index of refraction only slightly lower than that of crown glass, and its high Abbe number yields low chromatic aberration, altogether making it an advantageous material for eyeglasses and sunglasses.

Does CR-39 block UV?

Results: All the tested lenses absorbed all of the UV-B and at least 99% of UV-A. Conclusions: These data suggest that UV tinted CR-39 lenses provide protection against UV radiation that meets the ANSI Z80. 3-1996 Standard for non-prescription sunglasses and fashion eyewear.

What is the index of refraction of CR-39?

1.49
In the case of CR-39 plastics, the Refractive Index is 1.49, meaning that light travels at almost half the speed through it than it does through a vacuum. The range of the Refractive indices of different lens materials ranges from 1.49 to 1.74. The higher this number, the slower the light moves through it.

Does CR-39 have UV protection?

Is CR-39 better than polycarbonate?

In comparison to polycarbonate, CR-39 provides vastly superior optics, rating just one rung below the material with the highest ABBE value: crown glass. If you choose CR-39 lenses you commonly find that UV-protection comes at an added cost because, unlike polycarbonate, they aren’t inherently UV-protected.

What is the meaning of CR-39?

CR-39 stands for Columbia Resin #39. This stems from it being the 39th formula of the thermosetting plastic developed by the Columbia Resins Project in 1940.