[7453K]

i have this ink thats primarily composed of carbon black, and some aliphatic hydrocarbon which it does not name. The weird thing about this is that it NEVER dries, ive has some of the ink sitting on my counter for about 3 months, and its still easily wiped off, still wet.
It says its meant for non-porous surfaces, so i know that it not supposed to dry on the counter, but how does this work? i would think that everything dries up at some point right? so how does this whole for porous and non-porous surfaces work? like how do you determine which solvents to use when creating something that will not dry on non-porous surfaces ect.
thanks for whoever helps.

[macman104]

You just choose something that is very very nonvolatile I would imagine, although I'm not 100% sure.  Longer alkyl chains I should be less volatile than shorter ones.

[7453K]

alright thanks, but i would still think it must evaporate at some point. or does it have something to do with the environment its in? like if water is in a really humid environment it wont evaporate as fast right?

[macman104]

Correct, so the environment may have something to do with it.  It very well may evaporate at some point, or...it may not, if conditions never provide it with the opportunity to do so.  You may lose water content, or other things like that over time (if there are other volatile compounds present).  So, just because it didn't completely evaporate, does not mean it is the same composition as before.

[7453K]

alright thanks.