OK- The scale is Glass most resistant at 10 untreated CR39 is 1.
All without AR. My numbers-
Poly 6
RLX factory scratch coat 7
Trivex 8
Yes- No - Maybe???
OK- The scale is Glass most resistant at 10 untreated CR39 is 1.
All without AR. My numbers-
Poly 6
RLX factory scratch coat 7
Trivex 8
Yes- No - Maybe???
Last edited by Uncle Fester; 07-26-2016 at 02:10 PM. Reason: DOH...Now I get it drk!!!
After reading that, I need a Bayer.
Nice thread, UF. I like the idea of quantifying relative scratch resistance.
I wonder if there's an agreeable way to formalize a technical definition for ophthalmic lenses? Do factory scratch coatings have documentation indicating performance metrics?
They do Hayde- It's the Bayer test.
I put my faith in the subjective real world!!!Originally Posted by drk
Anyone in the trenches care to rate your experiences?
Colts lab in Florida probably has that, not sure if they would want to share it?? Someone with more influence than me might pry it out of them??
Not influence, money. They do not run a charitable operation.
if someone is willing to supply samples, I can do a scratch test with a diamond stylus and provide scratch depth data, given a set pressure.
It was proven in the 1980s that coated lenses were more scratch resistant than uncoated ones, and the extra treatment gave opticians an extra sale and more money.
These days you can have extra coatings of all sorts and reasons and find customers who will pay for it, and the more expensive the application the better for the opticians pockets.
The best lens in the older days and still today, was and is CR39 because its optical qualities are without question the closest to glass. It can be easily scratch coated, and can be tinted by the opticians in house lab.
It does not have to be worked on in an outside laboratory on machinery worth a few hundred thousand dollars to apply an Anti Reflex coating with all the bells and whistles.
With all the advertising done on the web by internet companies selling inexpensive glasses it might be wise for the optical retail dealers to go back to the basic way of mounting lenses into eyeglass frames.
I'm getting positive feedback that trivex doesn't scratch as easily as even Foundation or TD2. They seem to be better than RLX.
Anyone else want to dispute or verify this anecdotal evidence???
It all depends on the hard coat. A TD2 type of lacquer coat will trump most if not all spin coats. A TD2 anything beats RLX on anything.
I'm not 100% sure but I'm pretty sure that Trivex requires a hard coat just like 1.60 or poly and is never dispensed without.
Basically all materials are as scratch resistant as their top layer, the scratch coat. Polycarbonate without an applied coating can be scratched incredibly easily, definitely not a 6. Same with 1.60 and 1.67, not 100% sure about trivex because I've never surfaced it and get it pre-coated all the time.
Last edited by Tallboy; 07-28-2016 at 05:21 PM.
I was assuming all are "factory" scratch coated. I was also under the impression Trivex was not coated but I'd be happy to hear from someone in the know!!!
My experience with trivex being closest to glass comes from a stone mason who was esophoric (3^ out ou) and insisted on glass.
He was adamant that when he was up on a scaffold he wasn't going to climb down to rinse the lenses when they got covered in stone dust-- yeah yeah safety goggles I know-- Anyway when he tried trivex for the first time he was impressed that they did hold up longer but glass was still the most resistant.
As far as factory src coating, yes, but who's factory? And what type of coating? (Spin, lacquer, ect) All trivex come with a minimum of a spin coat as do all lenses other than CR ( CR is the only plastic that you can get uncoated, unless you talked a surface lab into sending a lens that they didn't backside coat on purpose for you.)I was assuming all are "factory" scratch coated. I was also under the impression Trivex was not coated but I'd be happy to hear from someone in the know!!!
My experience with trivex being closest to glass comes from a stone mason who was esophoric (3^ out ou) and insisted on glass
He was adamant that when he was up on a scaffold he wasn't going to climb down to rinse the lenses when they got covered in stone dust-- yeah yeah safety goggles I know-- Anyway when he tried trivex for the first time he was impressed that they did hold up longer but glass was still the most resistant.
All the others have an SRC for a reason....All other plastics are softer than CR. The softer the material (substrate) the more easily scratched. Poly and Trivex are very soft materials ( a better word would be that they have more elasticity.) Hence their inherent impact resistancy.
So if there are different coatings (there are) I would rate scratch resistancy of materials based on softness of the material;
Trivex
Poly
1.74
1.67
1.60
CR
I vividly remember a video showing poly penetrated by a sharp falling weight vs. trivex. If trivex is as soft as poly how could this be???
Trivex has more elasticity than poly, hence top of my list.
If you want the physical properties of these lenses you can go to MatWeb for all the info that you need.
http://www.matweb.com/search/MaterialGroupSearch.aspx
Yeah I don't think most people here know the specific names of the polymers for 1.60, 1.67, 1.74 and Trivex though dick
Unfortunately, that is the case. Get the specific details from the manufacturer of the lens blank and proceed from there. But, then again, its really not that important, is it.
Are there any concise articles or explanations on the various scratch coatings that are in use these days?
I'd love to know more about them.
cs
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote
Bookmarks