Hello,
I got curious about this and did a couple of tests in case you find them interesting.
Background:
I have no idea about vinyl formulation, but all the formulas I have seen online in patents etc. include some form of wax/plasticizer. The serious literature I could find is very old, and things might have changed and newer ingredients available, however I don’t think this is an active development field since many years ago and I still expect to find some form of plasticizer there.
Even if those are not used as mold release, as stated above by
@SIY , it does not mean they are not going to migrate to the surface and leach, if they have enough mobility.
This test does not intent to be exhaustive let alone quantitative, I would need a lot more time and work to do that. You can put it in the “anecdotal evidence” drawer, but at least it will provide some real data to stir the discussion.
I have chosen two records to test. I received both new and factory sealed. I never cleaned them. I never touched nor used them. I chose one record made in Europe and another made in US, as in my experience (not in vinyl formulation but in general in the chemical industry), ingredients tend to change in between regions due to tradition, availability, REACH, etc, etc.
I received the European record a bit over one year ago, it was published in 2022 so I guess it was made sometime in 2021 or 2022, enough for plasticizers to migrate in to the surface but still recent enough to call it “new”. It is one of these cheapo euro compilations that you find often at the FNAC. I believe many of those are self produced.
The US record I received it earlier in 2022 and is a classic record (A Jolly Christmas from Frank Sinatra) that could have been made any time, but is a recent edition, what you would get if you buy this album new nowadays, I don’t think it is older than a few years.
What I did was to put a bit of n-heptane on the surface of the record (on the inner groove so that it does not spread too much through the grooves and because Xmas is approaching and I might fancy to listen to old blue eyes haha) and recollect it to a vial. I repeated this a few times over a surface of ca. 5 cm2 (not measured, might be a bit more or less from one record to the other).
When I did this, I noticed that the solvent left a very slight mark (at the edges of the solvent drop) on the European vinyl, what tells me there is soluble stuff on the surface. There is also a very slight mark left on the US record but it is much more difficult to see, barely noticeable.
I chose Heptane because it wont damage the record too much and most importantly because it might be a decent enough solvent for apolar waxes and plastizicers that might migrate to the surface. I preferrend not to use lighter solvents like hexanes or pentane to avoid as much as possible that they penetrate the substrate. Please note that the solubility of those waxes (for instance carnauba and others that I found in the vinyl patent literature) in heptane is not very high, but considering the small amounts were are aiming at here, it should be good enough. If there are other polar additives there, or high molecular weight waxes or other polymers, heptane is not going to extract them. As heptane will not penetrate much in the PVC, we can assume that whatever it extracts is on the surface, either because it migrated there or because it was already there from the beginning.
Then I put a couple of drops of the extract on Zinc Selenide IR window and obtain the FT-IR:
The EU record extract contains a fair amount of material. The spectrum matches that of low molecular weight Polyethylene (wax).
View attachment 321077
The ZnSe window does not allow to see the signal at 700 cm-1 typical for these substances.
The match vs a reference library is not perfect (most specially the signal at higest frequency) but is pretty decent:
View attachment 321078
The US pressing extract has much less material. I struggled to get a decent spectrum. As you can see, there spectrum has more noise because the intensity of the absorption bands is really weak. What it shows is also some kind of polyethylene wax, but most probably different to the EU record. The fact that there is less in the extract is either that it is a wax with higher molecular weight that has less mobility that migrates less and/or is less soluble (most probably) or it contains less to start with.
View attachment 321084
again compared against a library:
View attachment 321087
yup, some sort of polyethylene wax.
I was expecting to find some carnauba or similar ester stuff, but definitely there is no ester there.
Well, as conclusions, what I observed here is yes, new vinyl might contain some wax on the surface that in some cases you can wash with some soap if you want to. If washing this is beneficial or the opposite, I cannot tell.
In other cases, like the US record tested here, i doubt that you do anything at all when you wash the record new.
If there is interest, I can wash the two records and repeat the test, to see if the washing is effective and to confirm that what I am extracting is in the surface and rule out that the solvent penetrates the PVC. I can also leave the washed records for a few months and repeat the test to see if new material has appeared on the surface. Just let me know.