A Tall Order? Trying to Find Optical Grade Flexible Film 2

[Bikeman55]

I am searching for a protective plastic film for use over convex glass lenses. It needs to be optically clear, self adhesive but removable, flexible with enough stretch to conform, scratch and tear resistant, 2-4 mil thickness. During testing we have used 3M Paint Protection Film successfully but of course it is very hazy. Not sure where to go from here and would really appreciate some expert input.

Thanks in advance!

Bikeman

 

[MacGyverS2000]

Define optically clear. 99% transmission in the visible? 99.5%?

Define protective. Protects the lens, but scratches itself? Does not scratch at all to 'X' hardness grit?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Demon3]

Such films come installed on some LED flashlights (on top of the glass) so they do exist. I would imagine they are made of for example SBS (e.g. Kraton or Styroflex) as they are clear and have enough tack to hold them in place.

Even Seran wrap or Cling Film if you're in the UK, would have a shot at working.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Compositepro]

Flexible vinyl films are frequently used for temporary protection. They can be very clear and distortion-free, and can stick to glass without adhesive or leaving a residue. They are soft however.

 

[Bikeman55]

The idea is that this would be sacrificial cover. We would replace it as necessary when it becomes scratched, it needs to be thick enough to take care of the lens underneath. It is a photographic application, maximum transmission possible, 99.5%??
Thanks

 

[Bikeman55]

Everything I am finding claims to be "optically clear" but when we try it it is hazy or causes distortion. We need something that is literally invisible when applied. I looked at the Kraton and Styroflex, they appear to be along the lines of a seran wrap, need something beefier than that. Would appreciate any suggestions.

Thanks!

 

[MacGyverS2000]

I don't think you're going to find something that's 99.5% optically clear and still have the durability and flexibility you desire... they're somewhat mutually exclusive. You can get close, but if you want durability in a flexible plastic, I think you're going to have to live with some loss of clarity.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Bikeman55]

Pretty much what I've been finding. If I can deal with close, what do you think the best choice would be?

 

[patprimmer]

Acrylic will be the clearest, polycarbonate will be the toughest, cellulose propionate will be be a good overall compromise if you can get it, polyester will also be a good overall compromise, polyurethane and silicon rubbers will be flexible. EVA might be worth a look, however haze vs temperature resistance will be an issue. Ceran wrap type products tend to be low vinyl acetate type EVA or plasticised PVC.

Most of the polymers listed will need heat to form them. Adhesion without losses at the interface is another issue altogether.

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

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

for site rules

 

[HDS]

Look at visor tear offs for helmets of race cars and motorcycles. However they may not be good enough for photography.

3M would be one of the more likely places to find it . Maybe Nito.

 

[Demon3]

A trace of oil should allow you to hold the film in place and avoid losses due to air bubbles.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Bikeman55]

Thanks for all the helpful suggestions. We have tried everything here and much more, just cannot seem to find that combination of stretchiness and clarity. Regarding post from HDS, cannot find anything about Nito, I take it that is a manufacturer??

 

[Demon3]

Try Styroflex, a special kind of SBS elastomer. Contact BASF for a sample. In the US try Keith Edwards.

It's very stretchy, clear and tacky.

No affiliation.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Bikeman55]

Demon3,
Thanks, per your earlier recommendation we got samples from BASF. Unfortunately, it was hazy. Pretty amazing product though, the way it recovers it's shape. Would be perfect if it was clearer.

 

[HDS]

I misspelled it in the first post but google found the right stuff right away

http://www.nitto.com/product/index.html

hear is the link for the tear offs. These are often layered on several times on a visor.

http://www.google.com/search?num=20...7K2aDQ&ved=0CBkQBSgA&q=visor+tear+off&spell=1

 

[Demon3]

If it was hazy, it wasn't pure Styroflex, it was Styroflex plus PE. I suggest you ask for a new sample.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Bikeman55]

Demon3,
Looking at the brochure that the sample comes in, it says it is Styroflex Styrene/Butadiene Block Copolymer (SBS), 2G66 The Second Generation. Guy I talked to was Michael Hamilton in Florham Park, NJ.

 

[Demon3]

Right, it's a special SBS block copolymer and totally amorphous so very clear. It is hazy when you mix it with PE though so perhaps that's what they sent. Elastic recovery on that product is around 400% or more. If you want to speak to a real expert on it then you need either Robert Huber (no longer his job but he can help) or Konrad Knoll both based in BASF headquarters Ludwigshafen. Say hi from me, I used to work there some years ago.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Bikeman55]

Thanks for the tip. I'll try to locate them tomorrow and email them.

 

[Demon3]

If you want, contact me and I'll pass you their e-mail addresses.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry