Flame Retardant Coatings For Unfilled Polypropylene?

I'm not aware of a particular product, but, if I were in your shoes, and a potential customer asked me that question, my answer would be, "You bet! Give me some samples of your fan shroud material and two weeks to do some research, and I'll find a product meets, if not exceeds, your required specifications."

From there, I'd be on the phone, internet, whatever, contacting manufactures of flame retardant coatings, getting help, securing samples, etc. And I'd get that job!!!!

Good Luck

Viper18,

Have you check out any of these?

Polypropylene is a difficult material to paint. Be sure the paint supplier knows you are coating a polyolefin. It and polyethylene are very slick and will require special surface preparation for adhesion.

As a sumer job back in 1989 I was hired to modify EU manufactured Biotech instruments so they would pass CSA special inspection. One of the task was to diassemble some and paint the inside with ignifuge water based paint. The test was to lite a plastic shaving, if the plastic would sustain combustion like a candle, paint it. I think they were ABS based. I was later servicing these instruments, many of which had the inside paint flaking. No special priming or cleaning were performed initially, I think it should have been scuffed or glass beadded at best, cleaned with a hard solvent at least. Polypro is a lower surface energy plastic than ABS, in an environnement with abrasion and vibration such as yours, I would not think it would be a good solution. The product manufacturer should engineer the proper shroud to do the job, this was what did back then, to have the EU manufacturer change some production steps in order to stop the stupid job of dismantling brand new instruments to perform real simple stuff to implement in prod, changing plastic type being the hardest.

The idea of incorporating flame retardant additives into the mixture of polypropylene for making the fan shrouds is what the customer is currently doing. It works fine....but the cost of the fan shroud made from this mix is considerably more expensive than if it were just made of the unfilled polypropylene. The idea is that if the polypropylene fan shroud could be coated with a flame retardent paint or film of some sort, then maybe the cost for producing this type of fan shroud would be cheaper than that produced from the special mix stuff. Since the volume useage of the fan shrouds is considerable, (tens of thousands) then this could be a tremendous cost savings on the bottom line.

Painting un-etched poly pro is a folly.

Good luck.

Any ideas on how polypropylene could be etched? I think that in some of my research efforts on this topic I ran across where in some sort of patent description they discussed etching the surface with a flame treatment prior to application of a paint-like coating system comprised of flame retardant additives. If I can find the proper transition layer of coating, primer, etc....or material which can etch polypropylene, then I should easily be able to overlay a standard flame retardant paint coat system on top of it. If anybody has any ideas on how polypropylene can be etched....I'm all ears!

Flame treatment, or corona discharge treatment will work. They're both fairly well known in the industry. I know of no mechanical way to get things to stick to PPro.

Some ideas here.

Rather than quoting them, I'll just pass it along. This is an overall pretty good site for coatings issues.

http://www.finishing.com/61/59.shtml

Thanks for the information....the web-site you gave was loaded with good stuff and has me going in the right direction finally.

Sure. Let us know what does the trick.

It may be possible to metal spray it with aluminium. This was a common practice for fire proofing wood in the 40's thru 60's.

Not knowing your part details - it might be worth the experiment. PP is good for about 140 ⁰C, but the wall thickness is going to be very pertinent in terms of the 'heat flash' involved.

Vacuum Metallizing might also be worth investigating, but it would have to be thicker than usual to be of use. You might consider electroplating (or spraying) over a vac metal copper film.

How the whole result performs if a big working temperature range is involved, is another question. _{(differences in coefficients of thermal expansion)}

Prime with either BONDiT A-43, 3M 05907 Polyolefin adhesion promoter or Transtar 1023 TPO Adhesion promoter.

Not sure which one would be compatable with your coating.

Hi,

contact Walt at <email removed>, he can help you for proper coating advise.

regards,

Sharad

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