autoclavable and resistant to chemicals plastic

[LeoG]

I am looking to replace current material which is PVC with a more durable yet still functional material. I will perform a study but want to include the right selection with a winner the first go around.

the product is being used in a "critical environment" and does get sterilized (in an autoclave) and is exposed to various disinfectants/chemicals

the White PVC discolors orange/brown after autoclave, blue us better but still darkens and doesn’t do well with the harsher chemicals.

• the process is extruded
• the material needs to be durometer shore A – 80 to 90 range
• should withstand:

o Minimum # of Cycles to Resist: 20
o Sterilization Temperature –124.0 C +/-0.5 C
o Sterilization Time –40 minutes
o Pre Vacuum level –(psia) 2.7
o Drying Time –20 minutes (2.7 psia)

• Is exposed to the following chemicals:

o Vesphene II (Steris) -1 ounce per gallon
o LPH SE (Steris) -1/2 ounce per gallon
o Process NPD (Steris) -1/2 ounce per gallon
o TBQ (Steris) -1ounce per gallon
o Coverage Plus NPD (Steris) -1/2ounce per gallon
o Spor Klenz Ready to Use (Steris) -Undiluted
o (peracetic acid and hydrogen peroxide solution )
o 5.25% Sodium Hypochlorite (Steris) -5000ppm
o 5.25% Sodium Hypochlorite (Steris) -Undiluted
o 70% IPA / 30% Water –Undiluted

So far I have selected 2 materials for the study with a handful of others as candidates (durometers may be too hard):
• Santoprene 201-80
• Eastman AP007

Please feel free to comment and/or suggest.

 

[patprimmer]

Nylons 11 & 12 might be worth a try.

A hydrolysis resistant polycarbonate might be worth a try, but I am unaware of the nature of most of the chemicals you list by trade name.

Knowing the ph of the solutions would help a bit. Nylons don't like anything with a real low ph.

PC does not like heat and high ph nor aromatics nor chlorinated hydrocarbons.

Time and temperature of exposure to chemicals other than autoclave is also quite important to know.

Regards
Pat
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[LeoG]

Pat,

Thanks for the reply. I don't specific pH levels on the chemicals but these are all disinfectants used to clean, kill and remove organisms from cleanroom environments. Some are nastier than others, like for example Spor Klenz and the Decon Spore. The study we are performing is 7 and 14 day complete immersion with the listed chemicals with autoclave cycles before and after.

Resistivity to color change (especially white) and ability and flexibility to be press fit onto a SS rod are the other criteria.

Thanks,
Leo

 

[patprimmer]

Leo

I am not going to look up the make up of your list then look up chemical resistance charts

I have given guidelines about which chemicals tend to attack what plastics. You need to do your own homework.

Regards
Pat
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[LeoG]

Pat,

Understood and I wasn't expecting anyone to do any in-depth analysis here. I was just hoping for some suggestions from material experts since I am not a materials guru. I was answering some of your questions that you posed in order to provide additional info - maybe I misread your note.

I do have the pH levels of the chemicals:

Chemical Name Abbreviation Dilution pH Level
Hypo Chlor HC 0.52% 9-10
Decon Clean DC 1:128 9.5-11
Decon Ahol DA 70% 7
Decon Quat DQ 2:128 6.5-8.3
Spor Klenz SK RTU 1.5-2
Process NPD PNPD 1:256 10.2
Deconspore 200 DS 6.4:128 4
Coverage Plus NPD CPNPD 1:256 13
Clorox Clorox 1.00% 11.9
TBQ TBQ 1:128 10-11.4


Nylons would most likely have issues with the low pH chems and PC the opposite. i know i can go with some specialty polymers but I was trying to avoid due to cost etc...

In any case, thanks for your help.

 

[patprimmer]

The two with low ph will destroy nylon fairly quickly.

The alkali with limited exposure time at moderate temperatures will not hurt the PC.

Prolonged time at over 80 deg C hurts PC. This time is reduced as ph rises.

PC is most likely to fail due to aromatics or chlorinated hydrocarbons. It regularly fails as switch plates in operating theatres and even in abattoirs due to the disinfectants. I always presumed they contained phenol based aromatics that caused the problem.

Regards
Pat
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