Please help me with the following problem as I am not chemically wise
A spec of aluminium foil used for packaging of food stuff indicates
that there is 2 g of PVC per 1 sq m.
The EU directive puts a limit of 1 milligram of PVC MONOMER per 1 kg
So, is that foil OK or it exceeds the allowable limit of PVC monomer ?
I know that even up to 80% of PVC can be in form of additives and only
20% could be actual monomers. So, even if it is assumed that there is
20% of monomers in the 2g of PVC does it mean that the foil does or
does not exceed the EU requirement.
Many thanks in advance,
You need to be more clear and precise here. The EU directive most likely
refers to the residual amount of vinyl chloride monomer on the coating not
the amount of PVC polymer. PVC is poly(vinyl chloride) and is relatively
inert as long as it is below 150 C. PVC is made by polymerizing vinyl
chloride. Typically, the amount of residual vinyl chloride monomer is
measured in the parts per million or even billion level. You'll need to ask
your supplier for that information. Referencing the exact EU standard will
aid them in helping you determine if you are in compliance.
It does not seem so...
The construction of the foil is as follows :
a. aluminum layer
b. primer ( PVC)
When they make the foil it is heated to temperature over 150 C (curing
the lacquer coat). In this temperature the layer PVC breaks down to
some toxic compounds. In Germany they banned foils like that some 6
Many thanks again,
firstname.lastname@example.org (Jerzy Zi?ba) wrote in message
Time is just as important as temperature. The lacquer most likely
cures quickly at 150 C, so the exposure time is short and unlikely to
cause the PVC to degrade. Even so, it is impossible to predict the
amount of monomer in the foil so you will have to have a sample
Frank is right. The regulation states that the for food packaging, maximum
amount of residual vinyl chloride monomer is 1 mg of monomer per kg of PVC
polymer. In other words, 1 part per million of vinyl chloride monomer
(1.0E-06 g of monomer for every 1 g of polymer).
You'll either need to get a compliance statement from your supplier or
submit a sample of your adhesive to a certified outside laboratory for
testing. I'm not familar with any of the compliance labs in Europe. Does
anyone else know?
email@example.com (jitney) wrote in message
If your business (or your employer) is trying to sell products in
Europe, they certainly care.
I've worked for 5 different companies in 7 different industries over
my 14 year career. The companies have always sold products globally
and have always had foreign competition. The days of the US not
worrying about the what the rest of the world thinks are gone - with
the notable exception of unilaterally enforced regime change.
The (other) funny part is, the US is actually ahead of Europe on this
particular regulatory curve. Content limits in the US, while recognized,
are not formally legislated as they are in the EU. Residual vinyl monomer
content of items for direct food contact in the US is recognized as safe at
levels <10 ppb (billion) for rigid packaging, <5 ppb for flexible packaging.
(Source: http://www.packaginglaw.com/index_Ask_PastQuestions.cfm?id#7 )
The EU actually allows more vinyl monomer (up to 1 ppm), so long as the
manufacturer shows that it is non-migratory (no more than 10 ppb migrating
to the packaged food).
Vinyl for infant chew toys is another matter.
R. David Zopf
Hmm... Looking at the definitions at the beginning of this document I
interpreted it as 1 mg of monomer per 1 kg of foil...
?? One g of one substance has a different number of molecules than one
g of any other substance. Hence there is no relation between PPM and
mg of monomer in kg of polymer.
Another thing is : does it mean that in one kg of PVC is just one mg
of its monomer ?? If yes, what is the rest of this stuff i.e. the
remaining 999 g
of polymer ?
I am getting lost here ...
I think it is in Germany... the name of the city sounds like : Neeren
Ok. let's see if I can clear this up for you. What the regulation is
concerned about is how much unreacted monomer is left in the final polymer.
The whole idea is to minimize the amount of highly reactive small molecules
from the relatively inert large molecules.
The polymer poly(vinyl chloride) is made by polymerizing the monomer vinyl
chloride. Just like bread is made from flour. The regulation you have
cited requires that any unreacted vinyl chloride monomer left in the final
polymerized PVC must be less than 1 ppm (1 mg of monomer per 1 kg of
polymer). If this regulation applied to bread, this would mean that you
could have 1 mg of unreacted flour per 1 kg of polymer. Don't confuse the
monomer, vinyl chloride, with the polymer, PVC. That's like confusing flour
Is that clear?
In polymer analysis, parts per million is usually interpreted to mean
mass per unit mass, not molecules per molecule. Molecules per molecule
is a useful figure when comparing molecules of similar sizes, but
not so useful when for comparing monomer (tiny molecule) vs. polymer
The average length of the polymer chains (molecules) in two samples of a
given polymer are not necessarily equal. Also, the distribution of
chain lengths may not be equal, even when the average is the same, but in
order to keep it simple, let's ignore that fact for now. We'll assume
that a given polymer sample consists of a certain number of molecules of
residual monomer, plus a certain number of polymer chains of length N.
Greater chain length implies greater molar mass, so greater N implies
fewer polymer "molecules" (chains) per 1 kg.
Completely neglecting the residual monomer content and any additives which
may be present, 1 kg of a given PVC may very well contain a different
number of molecules than 1 kg of another PVC if the chain lengths are not
Now, suppose we are comparing two PVC samples, which both contain the
same number of residual vinyl chloride monomer molecules, but which
contain polyvinyl chloride chains of different lengths. Let each sample
have a total mass of 1 kg. Count the number of molecules of monomer
and polymer in each sample.
If the average length of the polymer chains in sample A is greater than
the average length of the polymer chains in sample B, then there will
be "more" vinyl chloride monomer in sample A than in sample B -- on a
molecule per molecule basis -- when in fact the total monomer content
in each sample is equal!
Compare mass to mass, and this problem goes away.
Probably significantly less than 1 mg, assuming the polymerization
was reasonably efficient. These days, the amount of free vinyl chloride
monomer in PVC is extremely low indeed. 1 mg/kg is the maximum allowed
in Europe, but I would be very suprised to come across any PVC which
contained that much.
If you want to know for sure, a good test method is headspace gas
chromatgraphy. If you are concerned about how much vinyl chloride
monomer will present at elevated temperatures, simply perform the
analysis at elevated temperatures.
Hope this is helpful.
firstname.lastname@example.org (Dave Palmer) wrote in message
VERY !! :-))) many thanks to you and all other guys who were kind to
It is quite clear that unless it is thorughly tested it will be
impossible to come to any definite conclsions.
Thank you again...
In fact, since that european legistlation came into play, it is nearly
impossible (for the resin manufacturers) to sell PVC resin if VCM levels are
not below that mentioned ppm level. Further more - consider two aspects of
PVC article manufacture: 1) PVC is not used neat but compounded to enhance
its processability (mostly with stabilizers and lubricants) and its
properties or lower it's cost. Of that, plasticized PVC contain 15%-45 %
plasticizer, reducing the resin presence in a compound significantly. Some
formulations can contain large amounts of CaCO3 filler. VMC theoretical
level would drop, as now it is diluted by all the additives. 2) Any article
needs to be formed, which requires heating to soften or melt the compound -
VCM is volatile, much of it (of the residual level in the resin) would
escapeduring that phase. It is often drops below detection levels in the
final article, though mass spectrometry is becoming ever more sensitive...
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