On 5/3/2012 7:59 AM, Tegger wrote:
wrote in :

On 4/28/2012 11:59 AM, Tegger wrote:
...

By law, plastic headlight lenses must be coated with an anti-abrasion
epoxy. ...
...

Well, no, not quite...

NHTSA has a bunch of requirements that lighting must meet but they do
not mandate any specific material or manufacturing technique, only the
performance requirements the end product must meet.



You're right.

But meeting those performance requirements effectively means the
application of a coating on the underlying plastic, since there currently
does not exist a practical plastic with the stability and surface-hardness
required to pass the tests without a coating being applied. My
understanding is that the coating ends up being a cross-linked polymer, an
epoxy.

I've no clue on actual materials; whatever the treatment(s) are the
spec's are performance not material based is the point.

The abrasion one is probably as minimal of a one as any; I expect the
photometry and UV testing are at least as difficult to meet. To my
surprise an impact test itself didn't seem to be mentioned...

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