Biocompatible polycarb cleaner?

[sdk_imported]

I'm tyring to find a biocompatible cleaner for a polycarbonate medical device component. We have recently failed ISO-10993 irritation testing on parts cleaned with Oakite 61B. We are suspecting the cleaner. Any help you can provide would be helpful. Thanks.

 

[Pud]

I should think ethanol or isopropanol would not affect the PC.

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

Harry is correct. I would use isopropanol as it is less aggressive.

Regards
Pat
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[Pud]

Cripes!! Just looked up Oakite 61B:

Oakite 61 B is an inhibited, alkaline tank immersion cleaner for aluminum and aluminum alloy castings,
forgings and sheet. It is especially designed to remove stenciled identification inks (even baked-on inks),
oils and shop soils with no attack on the base metal. After rinsing, it provides a chemically clean, waterbreak
free surface. The material is free-rinsing and may be air-agitated if desired.
Oakite 61 B may also be used for soak tank cleaning of aluminum cake pans, meat molds and freezer
pans in food plants. It contains ingredients acceptable to the FDA and is authorized by the USDA for use
in federally inspected meat and poultry plants.[

Looks like it would make a good oven cleaner too!!

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

Sounds like a soup of many of the chemicals used in cleaning, pickling, stripping and chemical polishing in aa aluminium anodizing plant.

They are the sorts of things PC resists at moderate temperatures, however I would at least wear gloves and goggles handling them. The soda ash content is corrosive of skin.

Regards
Pat
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[sdk_imported]

Thanks for the input so far. IPA is not recommended for PC because it can cause crazing, cracking, and other damage. I'm not sure how real this risk is. The oakite was recommended by our plastics supplier for PC. We do three rinses including an ultrasonic soak for 5 minutes.

Any other suggestions other than IPA?

 

[patprimmer]

The problem with PC for medical devices is cleaning. If the parts are not stressed, it has reasonable resistance to alcohol and has been used for serving alcoholic beverages for many years with good results. Isopropanol is the less aggressive of the common alcohols.

The parts will eventually crack and fail, but how many use clean cycles in the meantime is anyones guess. Why was PC chosen and is it to late to change materials.

Regards
Pat
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[Pud]

Bayer reckon their Makrolon has good resistance to IPA. I wouldn't think their stuff is much different from any other.

See page 4:

http://plastics.bayer.com/plastics/emea/en/literature/pdf/34631.pdf?docId=34631

where it also indicates poor resistance to 1% Sodium Hydroxide in water!!

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

Harry

When I worked for Bayer, I got quite a few sales based on better solvent stress crack resistance as proved by trials.

We still did not recommend it into applications where solvents were involved, but on existing accounts we often obtained increased life compared to other brands. They told me it was due to their lower content of residual toluene (I think from 20 year old memories) from manufacture.

Regards
Pat
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[sdk_imported]

Unfortunately we cannot change materials - we have parts in hand the prototype tool is retired. The part is a single use medical device that does experience mechanical loading. If the device cracks it could cause an infection. So, I'm nervous about IPA. I will consider putting some parts on test in an IPA bath and see what happens. Although,I'm not sure how long that test needs to run to give me confidence and we are under deadline pressure - as always.

The test lab suggested using Simple Green. It looks like a mild cleaner:

http://industrial.simplegreen.com/ind_products_crystal.php

.We are leanign this route but the fact that it is an "industrial cleaner" is concerning. We're struggling to find a cleaner that has been tested to comply with the ISO 10993 biocompatibility test standards.

Thanks for all the input so far.

 

[patprimmer]

PC is mainly vulnerable to chlorinated and aromatic hydrocarbons. It is the aromatics that mostly cause the surprise as they are everywhere, sometimes as impurities.

Example, test PC in AR grade kerosene, good resistance when testing, then use in industrial grade and it breaks in seconds due to the 1 or 2% aromatic impurities.

If the parts are simply washed for a few seconds, surely a 24 hour immersion test should inspire confidence. Test real parts under real stress in the actual grade you will use.

Regards
Pat
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[unclesyd]

Here are two products I've seen used on Lexan. The DayDots product is FDA approved. You might want to get in touch with Winsol about their products for cleaning Lexan windows and wind screens available at auto and motorcycle part stores.

http://www.winsol.com/6045.htm

https://www.daydots.com/article.asp?HKEY=

002&strPRODH=001010&strMATNR=60211-01-11

 

[unclesyd]

Here is very good cleaner (DeContam) we used on plastics prior to metallizing. I don't recall if it was used on Lexan, so I would give them a call.

 

[sdk_imported]

Thank you for the suggestions. We will take a look at these cleaners. We are tentatively moving forward with Liquinox and Crystal Simple Green.