Scratch Resistant Polycarbonate

Sorry can't really help, but it's a great Q.
I don't really think 'scratch resistant glasses' are very scratch resistant.
I would wonder if glass isn't a better option, or maybe try and get in touch with the lens cutting/shaping people via your friendly local optican?

our vendor base seems to be either uninformed or unwilling to help much, either quoting HIGH numbers, or just 'playing dead' with the request

Yeah, I know the feeling... I sometimes wonder what these people actually contribute? After all, if you had the big numbers youd go to the manufacturer.
I shall curl up and watch this thread... prrrr zzzzzz
Del

You might look at GE DMX Lexan. My information is now several years out of date, but they were claiming greatly improved scratch resistance, without coating, for things like bezels.

Thank you ... I am doing some follow up on that now. Kindest regards ...

Are you looking for resins or film material?

We use PC film material from Bayer that seems pretty scratch resistant. Also try Autotype, they used to make a PC film that came with a UV curable scratch resistant coat on one side with the other side being printable. It could also be thermo-formed. The UV curing came after printing and forming.

If it's resins your after I'm affraid I can't suggest anything there.

Thanks ... actually, I am using a resin, but your information is helpful. Kind regards ...

You will never find a scratch resistant lexan or other ABS plastic for the simple reason that abrasive dusts are often mineral based and are far far harder than any plastic.

The antiscratch coating they vacuum deposit on lenses are made for a glass base. I suspect that stron bezels are made with thin ruby windows over ABS. The thin ruby (aluminum oxide clear) is very hard, and not that expensive in thin sheets, but more costly then Lexan. A thin sheet of hardened glass is a lot cheaper than corundum sheets to protect bezels.

Transparent aluminium, not really aluminium but a compound, best armor plate you can get, makes a good bezel cover sheet, but $$$.

http://en.wikipedia.org/wiki/Aluminium_oxynitride

Military buys it for armored car windows.

The photo is aluminium oxynitride, a pressure sintered clear material. The more it is compressed the smaller the voide get squeezed and the clearer it gets. The small disruptions prevent crack propagation = toughest armor made.

http://www.google.ca/imgres?imgurl=http://www.darkgovernment.com/news/wp-content/uploads/2009/07/transparent-aluminum.jpg&imgrefurl=http://www.darkgovernment.com/news/transparent-aluminum-created/&usg=__kmeZi1o8PevDswFan1l2hjIciZg=&h=403&w=560&sz=45&hl=en&start=1&um=1&itbs=1&tbnid=SeQWaBQX6z6hpM:&tbnh=96&tbnw=133&prev=/images%3Fq%3DTransparent%2Baluminium%26um%3D1%26hl%3Den%26safe%3Doff%26sa%3DX%26tbs%3Disch:1

GA for all the data, sir ... if only consumer products were priced like military :-) Kind regards ....

For what it's worth, I've heard the term 'high index' polycarbonate used in reference to the material used for eye glasses. The higher refractive index makes it possible to achieve greater corrective power from thinner lenses. Just a hunch that the atoms might be packed a little differently. I had a pair of this type of glasses for years, and they are very scratch resistant.

I think (only believe) you are correct. My last few pairs of PC eyeglasses have endured far beyond what I expected, and I've always been careless with them. As was posted previously, there is no perfect solution for plastics, but when we consider eyeglasses and iPods and other similar items, I think there must be some materials that offer a general advantage. Thanks, and kind regards ...

I've been reading some about nanotechnology advances and coatings that indicate the processes needed to coat Polycarbonates for scratch resistance are probably available. There are several organizations very active in this field that may be able to help.

Here are some links: http://www.nanotech-now.com/

http://iopscience.iop.org/0957-4484/

http://www.foresight.org/

There is a product that is made by 3M that is an antireflective coating, they may have something that will be scratch resistance. The material is adhered using by one of 2 diffrent ways, a low tack adhesive (similar to what you would use on your PDA for protection of the screen) and a more agressive adhesive (if i remember right it is what was used for lcd monitors) but i think they were expensive.

unfortunately i can not find the information i had on this material, but it should be fairly easy to find on the 3M website

Talk to the folks at Dontech http://www.dontechinc.com/index.html .

They are very smart about plastics and displays. Just the combination you are looking for. I've worked with them for many years. Good people.

A couple of thoughts. First , McMaster Supply carries a "scratch resistant" form of polycarbonate. It's not as resistant as sapphire, but better than standard polycarbonate. The second thought is that you can employ racing technology and use peelable layers of thin plastic that are removed as the outer layer becomes damaged.

There is a product that is a mar/scratch resistant polycarbonate.

You just have to watch if you are gluing or bonding. Because the top coat is anti-scratch, if you try to glue it - it tends to show odd spider web craze/cracks.

We use coatings by a supplier called Ultra Optics http://www.ultraoptics.com that are quite scratch resistant. Polycarbonate is extremely tough and impact resistant, but not very hard, so it scratches easily. Harder materials like acrylic are not very impact resistant. They resist scratching, but crack easier. Coatings can be applied by spray or spin coating. Ultra Optics does coating, sells the coating liquid, and also sells the machines to apply the coatings. The molding and coating should ideally be done in a white room. Dust particles seem to be magnified when they are trapped in the coating. At the very least, the windows need to be cleaned of dust before coating, and the coating needs to be done in a white room.

SAN is a plastic resin that is somewhat more scratch resistant than polycarbonate and more impact impact resistant than acrylic. It may or may not work for your application.

Dennis