I’ve been reading all over the place about HDPE chemical resistance. All of the data out there is slightly different.

I have specifically noticed that the HDPE chemical resistance information for chloroform, dichloromethane, and xylene is extremely inconsistent. I’ve seen many state that HDPE has good (but not excellent) resistance to all three. Then other’s will say that it has no resistance at all and should not be used for these solvents.

What gives?

It seems that many of the chemical resistance charts are unreliable. But which ones?

Does anyone know what the actual facts are here based on experience?

Is HDPE resistant to chloroform or not?

Is HDPE resistant to dichloromethane or not?

Is HDPE resistant to xylene or not?

I thought there were different types of HDPE plastics? I've read that #2 HDPE plastic is safe for naphtha but I'm not sure about the other solvents. The number is located in the center of the little recyclable triangle.

I think #2 means just that: hdpe

the other numbers mean other types of plastic (ldpe, PET, etc)

There is no HDPE #1 or #2, there is only HDPE. The #2 is for recycling purposes, and just means that the recyclable plastic type is HDPE.

Oh okay thanks for clearing that up.

#1 = PET, PETE
#2 = HDPE
#3 = PVC
#4 = LDPE
#5 = PP
#6 = PS
#7 = OTHER

See the following for more information on what those recycling code numbers mean:

http://www.ides.com/reso...stic-recycling-codes.asp

This is why SWIM uses glass. Also its not always just that the plastic is resistant or not but do plastic compounds or compounds used in the manufacturing of plastic get into or dissolve in the solvents used? This happens with water and plastic bottles and it certainly can with other types of plastic and solvents. As far as what goes into what with what solvent I don't know. Its easy to put a piece of plastic in some solvent and see if it falls apart or degrades heavily. But to see smaller amounts of minute compounds dissolving is another story that requires a targeted and thus expensive approach.