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I have an interesting question about the use of ethyl alcohol on polycarbonate windshields. I have had friends asking me about the use of Pledge Multi-Surface cleaner on their windshields. Some insist it will degrade, yellow, or even crack and soften their windshields. Others have been using it for years with no apparent effect.

Pledge does have a small amount of ethyl alcohol, but does it have enough to degrade and ruin motorcycle windshields or does ethanol do any damage anyway?

Pledges' MSDS states ethyl alcohol weight at 0.01-1.00 (http://www.scjohnson.ca/pdfViewer.aspx?pkMSDSId=367&language=en).

So what are the effects, if any, on using this cleaner on polycarbonate windshields?

Thanks

Greg E.
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JerShar
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    I'm not an expert in polymer chemistry by any means, but if you do a search on chemical compatibility of solvents with polycarbonate, most sources indicate no effect or only minor cosmetic effects from (near pure) ethanol on polycarbonate. Keep in mind that, in windshields, the outer layers are glass, so there shouldn't be direct contact with the polymer interlayer if the windshield is structurally intact. – Greg E. Aug 02 '14 at 00:30
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    And if you're ever concerned about a solvent's affect on a material, you can try taking a small amount of solvent and applying it to a hidden corner of the object. Not sure what would be best place on a windshield, maybe a lower edge near the dashboard. – user137 Aug 02 '14 at 06:22

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Not able to comment....

I think the main problem is propyl alcohol (not present in this cleaner). Propyl alcohol (propanol) is present in a lot of cleaning solutions and known to damage polycarbonate and acrylics.

Check this chemical resistance sheet:

Sheet

30% solution containing ethanol (ethyl alcohol) lightly attacks the plastic. However, a 10% (propanol) propyl alcohol already does the same damage. That is a factor 3!

LDC3
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JR_
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