UV and Opticaly Transparent Polymer

[AlexBygrave]

I am trying to source a UV transparent and optically clear polymer.
The polymer will ideally allow 200nm to 900(ish)nm to pass through with little or no attenuation; it should be durable, scratch resistant, injection mouldable and as cheap as possible!

I know this topic has come up before and I have read the two relevant threads started by tsingIn on 27 Jan 09 and 09 Dec 08. The best I have come across so far is a COC by Topas (

http://www.topas-us.com/tech/data/uv.htm)

however, below 280nm UV is rapidly Attenuated. Does anybody know of a different COC manufacturer or polymer that would do the job?

Cheers

 

[Pud]

COC is the best there is at those wavelengths. Been there, done that.

You might have a look at TPX:

http://www.mitsuichemicals.com/tpx.htm

but not much on UV transmission. It's a polyolefin, so I guess it's much as Topas.

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[AlexBygrave]

Thanks for the info Harry, I did check out TPX but I read that it was 8 times more expensive than PC! Which put me off a bit. Having said that I’m not sure how much the Topas is, any idea?

Thanks

Alex

 

[patprimmer]

TPX has an SG of 0.8, so it is really only 5 times more expensive, however last time I checked Mitsui was sold out and not accepting new business.

TPX absorbs at least some UV and is degraded in that process. I may have transmission curves buried somewhere in my library, but I will not dig it out unless it is seriously being considered and is potentially available.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[Pud]

Alex,

Depends where you are - I'm sure they price all plastics according to what they can get away with in a specific marketplace.

Contact your local Topas agent - when it was Ticona here in the UK, they used to be pretty good. No idea what they are like since Ticona sold the business.

Here in the UK it's much dearer than PC - mainly as it's used a lot for medical stuff.

It's odd stuff to mould - it is cloudy when molten and unless you are aware of that, 25Kg can be easily purged thinking that the barrel is still contaminated!

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[Demon3]

Hi All,

Pud, interesting that the Topas is cloudy when molded. That is very probably only true for the impact modified types. The reason being that as you heat, the refractive index of the rubber changes more than the polymer does so it's cloudy due to the refractive index mismatch. MABS does the same. I did a nice study and have a patent based on the effect.

Regarding the UV absorption, there's not much you can do. The UV absorption is due to the chemistry of the polymers so changing supplier won't help.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill