Safe Temperature Range for all plastic lenses

[Alan W]

Would appreciate help in learning what the maximum temperature tolerance for CR39, Polycarb, etc. Also, at what temperature would either or both hard cote and A/R become unstable after being applied to these plastic lenses.

Thanks,

Alan

[LKahn]

Question is this temp for curing a coating or temp for a tint machine? What are the circumstances of the temp and is it dry or wet (in a tank)

Would appreciate help in learning what the maximum temperature tolerance for CR39, Polycarb, etc. Also, at what temperature would either or both hard cote and A/R become unstable after being applied to these plastic lenses.

Thanks,

Alan

[Chris Ryser]

Would appreciate help in learning what the maximum temperature tolerance for CR39, Polycarb, etc. Also, at what temperature would either or both hard cote and A/R become unstable after being applied to these plastic lenses.
Thanks,
Alan

Alan that is an excellent question, even if we know all the end result of extreme conditions,

It all depend on the individual expansion coefficient of the base material and the coating materials.

Then it depends on the adhesion factor of the coating materials to the substrate under extreme conditions.

That is a pretty big order on which you probably never will receive a valid answer as there are too many factors involved. Like formulas of the different coatings and their adhesion factors which might vary from one manufacturer to another and they are all kept secret.

The most sensitive coating is without doubt the AR coating which is made of (SIO2= silicon dioxyde=glass) This would make it the hardest and least flexible coating that would (crazing, delaminating) fail if the base material would expand or contract under extrerme temperature conditions.

I do have a page on Polycarbonate Physical Properties:

http://optochemicals.com/polycarbonate_properties.htm

[Alan W]

Your information is well appreciated. At the risk of being a little pushy, please allow me to ask one more question.

I think we would all agree that the characterististics of a medium wave IR heat source can be that the substrate is heated more or less at its surface, rather than throughout the material.

The question:
Would it not be somewhat safer to the lens that has A/R and hardcote on it? And, would that method (as opposed to "baking in an oven) facilitate adhesion of a powder coat?

(OK...I snuck in an extra question...I buy dinner!)

Alan

[Chris Ryser]

The question:

1. Would it not be somewhat safer to the lens that has A/R and hardcote on it? And, would that method (as opposed to "baking in an oven) facilitate adhesion of a powder coat?

We have worked with a french made IR source for testing purposes in the older days. It was amazing how the coating polymerized whyle the substrate stayed cool. This principle is used today in many fields from automotive painting to coating frames.

We never followed up as we were geared towards the retail end of the optical and everyone had just gone into UV curing of hard coats.

[Alan W]

You're "one smart cookie!"

Several years ago I was a manager for US Eyewear. We dealt with Korean frame manufacturers. Interstingly, we dealt with some "subs" for Metzler and others and discovered where the "truth" was on frame finishes. And, yes, there's junk and there's good stuff. And, some of the subs made both. Depended on who the contractor was (I.E. Brand) and . . . what type of powder (epoxy, polyester,etc.). I wish the dispenser (If he knows) could relay that type of information to the consumer. It gives one a genuine appreciation for quality in finishing once the knowledge is shared.

Alan

[Chris Ryser]

It gives one a genuine appreciation for quality in finishing once the knowledge is shared.
Alan

In the 70s european frame manufacturers were wondering how the japanese could make gold coated cigarette lighters that would not even get scartched while on metal frames the color coatings would just about fall off.

[Henry]

In the 70s european frame manufacturers were wondering how the japanese could make gold coated cigarette lighters that would not even get scartched while on metal frames the color coatings would just about fall off.

Chris,

Chemalux AR Coatings are made of patented nanocompsite materials which are polymers embedded with nanosize ceramic particles. It is the same family of materials as hard coating materials. The thermal expansion matches each other between Chemalux AR and the hard coating. Therefore, Chemalux AR is actually heat resistant, the only heat resitant AR in the world. That is one of the reasons Chemalux AR is very durable. In Chemalux AR coating process, the coating has to be cured at high temperature.

Henry

[Alan W]

Hi, Henry
At what temperature range is it cured?

[Henry]

Hi, Henry
At what temperature range is it cured?

Alan,

The normal curing temperature is around 100oC (212oF). The higher the curing temperature, the fast the curing. However, CR-39 cannot stand above 110oC. Thus, Chemalux AR can only be cured at lower than 110oC.

Henry

[Alan W]

Copy that!