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microcellular polyurethane chemical resistance to acid

microcellular polyurethane chemical resistance to acid

microcellular polyurethane chemical resistance to acid

(OP)
We use a microcellular polyurethane wheel on a conveyor.  
It is a "no flat" wheel of industrial quality.  Works nice in our application.  Can be found in mcmastercarr.
However we would like to bid to a customer who requires a washdown enviroment.  One of the requirements is that the wheel can withstand a spraydown for 30min.  The specifications ask for resistance of 2-12 PH.  
The only mention on the material safety data sheet for the wheel not the microcellular urethane says:

INCOMPATIBILITY (materials to avoid):  strong acids or bases.

I need more specific information or at least knowledge of whether the PH range is acceptable.

RE: microcellular polyurethane chemical resistance to acid

The microcellular material is qualitatively less resistant than solid material.  Does your wheel include any metal parts (axle, bearings), is it mounted on shafts with spacers, are the shafts stainless steel?

Suggest conducting some accelerated exposure testing.  Unless you have specific information on what chemicals, cleaners, etc., that the customer may use, I suggest:
1) At pH 1.0.  Use 0.1 molar nitric acid.  This is pretty severe due to the oxidizing acid.
2) At pH ~12.5  Use 0.1 molar NaOH diluted about 1:1 with commercial bleach solution (dilute sodium hypochlorite).
Use polyethylene pails of appropriate size as containers.
If samples withstand a week in these solutions (at room temperature), I think you should be OK.

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