Recycling PC lens

[gunningm2]

Hi,

I'm new to this and I've started a research project trying to recycle the waste polycarbonate produced when these lens are machined down to size.

What I need to know is whether the waste material which has been cur from the back of the lense will be coated in these anti abrasion and AR coatings or are these likely to be just on the front of the lens.

I understand that commonly these lenses are dipped first and then machined. Does these mean that it will be dipped entirely, front and back and covered in the hard lacquer?

I have done some tests on the lens that i've recieved and the hardness tests are showing that the front of the lens is alot harder that the back of the lens.. this to me says that it must have been spin coated (i'm assuming that spin coating just covers the front of the lens). There are some marks on the side of the lens which look like drip marks, again i assumed that this meant that when it was sprayed only on the front that soe dripped down the sides.

Can anyone tell me are my assumptions correct. does the presence of these drip marks on the side and the lack of harnesss at the back of the lens indicate that only the front has been sprayed?

And my other question is.. if i'm right and only the front has been sprayed then am i also correct in saying that the back of the lens is pure polycarbonate and has not been touched by anything.. (eg dipped in primer of some sort and then spin coated or coated in some other way on just the front of the lens)

Sorry if this is a bit basic and long winded but I'm new to this and I'm not having alot of luck getting info from the lens manufacturers.

Thanks again

Michael

[hipoptical]

Hi, Michael.
You will find that the material will be mixed. There will be poly that is dip coated and some that is spin coated, some A/R, some tints, some mirrors, some polarized. I think this is typically the problem in trying to recycle lens materials. Most labs will also edge different materials on the same edging equipment, meaning there will also be Cr-39 and various hi-index plastics mixed in as well. Labs that separate poly and plastics in surfacing will have a "purer" batch of waste, but that also will have some hard coat in it, due to cribbing. Lens manufacturers will likely be the only ones to have "pure" poly waste.
Hope this helps.
By the way... where are you, exactly? I lived in Ireland for about a year back in the 90s. I loved it there, and have always wanted to go back.

[rbaker]

I believe that you will find the cost of recycling will exceed the cost of the raw monomer. You will also have to look long and hard to find someone who will purchase your polycarbonate regrind.

Years ago we had an old granny who took all of our discarded lenses and bonded flowers to the ocular surface with clear lacquer. She then bonded a clip to them and sold them as jewelry. She did very very well.

[gunningm2]

I'm from Kinnegad in Co. Meath but workin on a research project in Athlone. Where in ireland did you live. Ireland can be fun, except for the weather...

I'm fairly happy that all the lenses that i'm receiving are Polycarbonate. Do you know where i can get anymore info on tinting, AR etc etc.. i was hoping that most of the material i have would be free of this seen as its coming from the back of the lense and not the front.

Im having some issues with processing the waste because theres seems to be a lot of burning going on. I was wondering was this due to the presence of some coating material or the other thing i was thinking was whether it could be due to the cutting fluid that was used. it contains some volatiles.

Anyway any info u can share with me would be appreciated.

What is your background in this industry if you dont mind me asking?

[gunningm2]

I believe that you will find the cost of recycling will exceed the cost of the raw monomer. You will also have to look long and hard to find someone who will purchase your polycarbonate regrind.

Years ago we had an old granny who took all of our discarded lenses and bonded flowers to the ocular surface with clear lacquer. She then bonded a clip to them and sold them as jewelry. She did very very well.

Not really in the business of discarded lens, more the waste from machining the lenses. There is plenty of waste and discarded each time a lens is machined and it costs to send to landfill. I'm pretty sure its mechanical properties arent that bad if a use can be found for it.

[humbleABOCtx]

Re: rbaker granny making jewelry

we used to take old discard lenses and handstone them down
to diff shapes...quirky hearts,stars etc,
drill a hole(s) in them dunk in tint to desired color(s)
then string it with nylon loop....
there you have a x-mas ornament.

sorry no sugg. for the waste biproduct..I'll keep my ears open

[chip anderson]

I'm pretty sure Polycarb is a very cheap product except when you buy it as an opthalmic lens or blank or buy it at Home Depot and the like. Suspect it costs next to nothing wholesale or in bulk.
I remember back when we could make PMMA lenses without regulation, blanks cost about a dime apiece, but you could buy plexiglass sheet (one 4x8) at a time and make your own for about a cent and a half (the sheet was better stuff than the extruded commercial blanks available). If one wanted to buy in huge quantities I immagne the cost would drop to only a few tenths of a cent a blank.
I doubt if there is much market at all for used lens blanks. Find someone who wants to make novelties out of it.

Chip

[Chris Ryser]

I'm fairly happy that all the lenses that i'm receiving are Polycarbonate. Do you know where i can get anymore info on tinting, AR etc etc..

Lots of information on my website at http://optochemicals.com

[nilisha]

Lots of information on my website at http://optochemicals.com

how can we find thickness of cutlens what is the formula of if please tell me


thanks & regards

[Chris Ryser]

measure it

[jefe]

Try Opticampus. http://www.opticampus.com/tools/thickness.php. Plug in the info, and you get an approximate thickness.

[Comma]

I think I'll make a shower curtain with them.
Guess where I'll put the minus and the plus lenses to really benefit of the view when my wife is taking a shower ? :D:D:D:D:D