Cr Hard Coatings

[sandeepgoodbole]

Hard Coating Liquids

What are the Hard Coating (Dipping Method) Liquids for Cr 39 are available ? Which of them are worth trying ?
Do Crs have different types ?
Which Liquid is suitable for which type?
Please give the addresses of the suppliers and oblige .

[Chris Ryser]

sandeepgoodbole said:
Hard Coating Liquids

What are the Hard Coating (Dipping Method) Liquids for Cr 39 are available ? Which of them are worth trying ?
Do Crs have different types ?
Which Liquid is suitable for which type?
Please give the addresses of the suppliers and oblige .

I did send you a private e-mail on the subject, hope it can help.

Chris Ryser

[JERRY HUANG]

Hi Sandeep,

Please check this site: www.luvantix.com


Ceramic Hybrid coating for any lens material by using sol-gel technology.

[sandeepgoodbole]

Thanks Chris and Jerry
Can you tell how the hardness can be Measured and Verified ?
Is there some Non Distructive Testing ?
We had few years back, a steel wool supllied with the Lenses. On rubbinng it, if no scratching occured, the Lens was deemed perfect. The lenses were too good.
The company vanished soon. They were like a Ill Physician with "Dolby" Stethosope !! They could hear a loud, what's happening around but could never dignose themselves.

Sandeep

[JERRY HUANG]

Hi Sandeep,

Accordingly, hard coating applied by sol-gel technology in Korea can achieve #6 pencil hardness for polycarbonate, #7 pencil hardness for CR-39.

I think you can send samples to them for testing.

Good Luck!

[Chris Ryser]

JERRY HUANG said:
Hi Sandeep,

Accordingly, hard coating applied by sol-gel technology in Korea can achieve #6 pencil hardness for polycarbonate, #7 pencil hardness for CR-39.

I think you can send samples to them for testing.

Good Luck!

Anibody can tell me which is the hardest.............................

100 or 1



Chris Ryser
:hammer:

[Chris Ryser]

sandeepgoodbole said:
Thanks Chris and Jerry
Can you tell how the hardness can be Measured and Verified ?
Is there some Non Distructive Testing ?
We had few years back, a steel wool supllied with the Lenses. On rubbinng it, if no scratching occured, the Lens was deemed perfect. The lenses were too good.
The company vanished soon. They were like a Ill Physician with "Dolby" Stethosope !! They could hear a loud, what's happening around but could never dignose themselves.

Sandeep

is the biggest BS. It all depend of how much pressure you apply. NO pressure it will do nothing on butter,,,,,,,,,,,,,,,,,,a lot of muscle power will scatch stainless steel...........

Taber Test or pencil test or haze test's are the standard and not steelwool which is controlled by muscle power.

Chris Ryser


:finger:

[sandeepgoodbole]

Taber Test or pencil test or haze test's are the standard and not steelwool which is controlled by muscle power.


HI!
Chris,

hat's logical. It also implies that muscle power is enough to scratch the Coatings available today. So, there is a need of the coating which cannot be scratched by common Spectacle user s and dispensers by using muscle power. Can you tell the stories of how the tests you have mentioned are done? All this is fascinating me, repeating my experiance just when I began to wonder, is there any thing left in our field which I do not know !!


:cheers:

Sandeep

[Chris Ryser]

sandeepgoodbole said:
Taber Test or pencil test or haze test's are the standard and not steelwool which is controlled by muscle power.


HI!
Chris,

hat's logical. It also implies that muscle power is enough to scratch the Coatings available today. So, there is a need of the coating which cannot be scratched by common Spectacle user s and dispensers by using muscle power. Can you tell the stories of how the tests you have mentioned are done? All this is fascinating me, repeating my experiance just when I began to wonder, is there any thing left in our field which I do not know !!


:cheers:

Sandeep

Sandeep,

You asked previously that you wanted to find non-destrctive tests...........there are none.......AS SOON AS YOU START TESTING THE RESULT IS DESTRUCTION.............you test until the substrate is damaged and the time or application it takes to do that is your result.

You do need laboratory equipment to do these tests and the simplest easiest way is to pay a research lab to to the tests.

Also read the article in by Peter Wilkinson Phd BSc(enh) recognized as the lUK'S eading auhority on spectale lens treatments in the latest british "Dispensing Optician" Novemeber 2002 edition. "Part1: Anti-Scratch and Hard Coats" and I quote from that:

""""""Slippery or Hard?
Weather a lens ca be easily scratched is as much a function of its "slippyness" we mean a lack of friction, which means that any abrasive particle glides over the surface easily without scatching it. By hardness we mean that the surface material is strong enough to resist damage when abraded. Some coatings include what may be called a "slippy" ingredient and this can be as beneficial as a hardcoat.

However, it should be remebered that "slippy' coat are extremely thin and do not last very long.

Although not sold with the words "slippy" coat, hardcoats that are created bi dipping in a tinting bath for a short period of period are generally of the "slippy" type. They should therefore be considered as considerably inferior to hardcoats produced by coating with a laquer. ''''''''''''''''


Much easier than to start testing what other people have done before you, buy hardcoated lenses, or buy uncoated lenses and do a good scratch restistant treatment (which costs you much less and apply it yourdelf} and sell a few of this type and a few of the other and watch out for complaints or come backs. You will find that you will get just abot the same result with either one.


Chris Ryser

[Jim G]

Geez, I'm gonna have to get to the Board more so I can reply sooner.

To expand a bit on Peter's treatise, scratch resistance is composed of three traits: slipperyness; resiliance; and, hardness. No one test measures all three; manufacturers tend to use the test that favours their product.

John Young, while at AO, was involved in developing the "Tumble Test" that supposedly was corrolated to real life use. We used it extensively but found it inconsistant.

Another common test is the Bayer test where a lens is held fixed in a pan of sand (or other controlled substance). The pan is oscillated back-and-forth a set number of cycles. The increase in haze is then measured and compared to a lens standard. This has generated some degree of acceptance on scratch resistant lenses (and controversy when used with AR coated lenses).

3-M developed the "Curved Surface Steel Wool" test where the grade of steel wool, the pressure exerted, number of cycles, and the curvature of the force (i.e. always perpendicular to the surface of the lens), etc. were all quantified. Some manufacturers still use and prefer this method.

The Tabor test is used extensively in other industries (paint for one) but has not gained wide acceptance in our industry (possibly because it is run on a flat sample).

Chris' comment that a test is destructive is true however, a piece of "4 ought" (0000) steel wool at the end of an experinced forefinger when used on the edge of a lens (to be edged off) can be a pretty reliable tool to SCREEN the relative effectiveness of coatings.

Generally, all the factory coatings are very good. Lab applied backside coatings tend to be a little softer as they have to absorb most of the tint and, being on the backside, tend to be exposed to less abuse. Again, the harder the coating, the less the tintability; and conversely.

Lastly, (and I know this is part of Chris' business so I expect a reply) Essilor has tested many of the "dip 'n cook" in-office products and published the results showing that they had the same OR LESS scratch resistance after coating than before. The majority tend to be simply silicone products that make the lens more slippery so dust 'n stuff doesn't adhere when dry wiping resulting in less scratching.

Hope this helps.

[Chris Ryser]

Jim G said:
Geez, I'm gonna have to get to the Board more so I can reply sooner.

Lastly, (and I know this is part of Chris' business so I expect a reply) Essilor has tested many of the "dip 'n cook" in-office products and published the results showing that they had the same OR LESS scratch resistance after coating than before. The majority tend to be simply silicone products that make the lens more slippery so dust 'n stuff doesn't adhere when dry wiping resulting in less scratching.

Hope this helps.

Jim,

After many years of knowing each other, you know that I went from just plain hardcoating, (and I was the second one to have a decent working hardcoat system in 1984 (UV-Cure)), also into what so many competitors called "the Snake Oil business" which was the "SLIPPY" type scratch protection.

It was never the dye-pot dip system. If you look at my US patents issued October 15, 2002, you will see I hate the "old smelly, slow working dye-pot", I found better than that.

We actually went into what Jim call just simple silicone treatments.

Jim, I guess ESSILOR never tested my version, because I never believed in the dip and cook type because of the same reasons mentioned, and never developed one.
Polysiloxanes of which there are hundreds of them are based on silica and are of a very complex chemical combination. They fill the pores of a CR39 lens (are not compatible with Polycatb) and provide a super slippery surface and therfore letting object slide off the surace. And, Jim, with NONE of the mentioned hard coat tests can you measure this type of protection.

Furthermore, are there any other scratch-resistant treatments available which also provide ANTI-STAT and ANTI-FOG properties at the same time................????

Less dust, due to the anti-stat, on a lens means less scratching when cleaned dry, which most people do. Anti-Fog protection is also an immense benefit.

I have been in the what Jim calls the REAL Hard-Coat development for just about as long or longer as anybody else. I do not dispute the word hard coat, it means a harder coat than the substrate. Therefore the surface resist's scratching longer and better than the original substrates surface.

A TINT-ABLE hard coat is not half as scratch resistant than a non tintable one.

And a VERY-TINTABLE hard coat is probably 70% less scratch resistant than good non tint able one. Has any of the hard coat guy's told you that?

But there are over 40 Million pairs of lenses treated world wide with the "just a silicone" or oh yeah, the "snake oil"and every year there is some more. This is not a small amount, at least not in my eyes.

Its a all in the eye of the beholder. Lens manufacturers want the optical trade to buy hard coated lenses, the coating machine manufacturers want you to buy their machines, and the others want you to buy the "SLIPPY" type.

Actually they all work. But one should not judge on the facts that there are some good and some not so valid tests for hard-coats while there are none of them for the slick coats. The slick coats probably win the quantity amount of applications world wide