TECHNICAL
QUESTIONS
1. What aging tests have been performed?
Do you reall y know what happens to the shelf stability of
these bottles if kept on the shelf 1-2 years?
We currently have the first samples of bottles
in our laboratory undergoing accelerated aging tests. The
interim report concludes a very positive progress of these.
Reverte™ has been specially formulated for a ‘long
dwell time’ exactly for this application and we are
therefore confident that within the first 2 years at least,
the bottles will show no signs of degradation on the shelf.
2. Has PGBC or Wells done migration testing
in the PET beverage application to determine if anything
migrates out of the plastic into the water in the bottle?
The additive was independently tested by
Smithers Rapra for migration in the PET form (see under Accreditations;
it is our conclusion there is no reason why the integrity
of the bottles would be compromised by incorporating Reverte.
3. If the bottles are programmed with a
stabilizer to inhibit the premature trigger and give it a
24 month shelf life, and many (or most) of them are used
in 3-12 months after production, and then discarded into
a plastic garbage bag, that gets compacted and goes into
a landfill and covered daily (with minimal or no light and
oxygen), how do you even know that the bottle ever gets the
conditions to trigger the initial degradation process, if
it is intentionally being retarded for 24 months? Have there
been any real world tests done to indicate that it really
triggers? (The simulated accelerated lab UV tests really
only indicate that it is capable of degrading if the right
optimal conditions are present, but does not reflect the
conditions the bottles really wind up in...)
Reverte™ contains a metal ion that
catalyses oxidation of the polymer chain causing serial chain
scission. This initial chain scission reaction requires metal
ions, oxygen and energy. The energy comes in the form of
free radicals generated by UV light / heat.
To stop the reaction taking place too quickly
we include a cocktail of free radical scavengers to take
the energy out of the system before it can be used in the
oxidation process. These scavengers are sacrificial which
means they are used up every time they take out a packet
of energy. When they are all used up the reaction takes off.
This gives the “dwell time” property that is
followed by the rapid polymer breakdown.
In addition (and here’s the crunch
that separates Reverte™ from other oxo bio additives)
we have another set of free radical scavengers that are extremely
efficient and immediately gobble up all the energy (free
radicals) that appear. This system is again sacrificial and
when the scavenger is all used up then the breakdown reaction
again commences in earnest. BUT, this free radical scavenging
system is effectively deactivated after a short UV light
exposure. This means that left to its own devices (in the
dark) product containing these Reverte™ grades will
have a longer dwell time before the various scavenging packages
are used up.
The photodeactivatable free radical scavenger
needs a certain level of UV to totally take it out of the
picture. This isn’t an exact science because it is
dependent on thicknesses, pigmentations and the vagaries
of weather etc, but it is in the order of 10 hours exposure
at 80kLypa. This is approximately 183Ly of total exposure.
You can see that this is quite low! (Yes, it’s in Langleys
not KiloLangleys).
For example in Florida sunshine this deactivation
level may be around 4 hours, in the Winter Arctic it’s
probably around 40 hours. By the way, the UV “trigger
dose” shouldn’t be thought of as a magic bullet,
try and imagine grains of sand on one side of a balance.
Even a short UV exposure will use up a portion of the scavenger
and this will shorten the “in the dark” dwell
time. This dwell time is controlled by the other scavengers
(not the photodeactivatable) and so should be fairly constant
at a given temperature no matter what.
The UV wavelength doesn’t have a significant
effect (natural light consists of a broad UV spectrum) but
of course the intensity does because it’s all about
energy!
Finally, once triggered it’s more
about temperature than light (although, of course, you get
some free radical generation from light energy), so once
it’s totally triggered it could be kept in the dark
.
Reverte™ products have been used in
wide range of real word applications over the years where
performance has been critical and marketing less so!!! Such
as agricultural mulch films and carrier bags. Testing in
the environment has correlated extremely well with our in
house test protocols and over the years we have supplied
this range of products into the marketplace we have yet to
find a spurious result.
4. Has Wells / PGBC gone through an FDA
food contact notification process (not just saying that they
comply with guidelines)? My understanding is that usage of
an additive in a new application (such as with PET), should
be submitted to the FDA to see if they have any objections.
No. We do not believe that we need to make
any submissions to the FDA as we have independent certification
(see attached under Accreditations) for the Reverte™ PET
additive.
5. Were the recyclability tests done to
the guidelines of the Association of Post Consumer Plastics
Recyclers’, or have they reviewed the tests (they are
the main trade group in the US)?
Recycling within the UK is extremely well
developed with regards to PET, and in fact the window of
materials allowed to go back in has become wider. We have
conducted extensive tests in PE post consumer recycling and
to a lesser degree PP. Our work with PET recycling has only
been conducted within our laboratory facility, however again
at this stage we see no contra indications; our plan is to
conduct further trials over the coming months.
6. What about landfill biodegradation. Does
PGBC or Wells have scientific studies indicating the technology
really would biodegrade in a landfill? (Typically the scientific
community would want to see evidence of anaerobic biodegradation
to be able to make the claim of effectiveness in the landfill.)
The FTC has some tough rules about landfill biodegradation
claims, and I’m concerned we could be a target without
the proper science to back it up. What studies have been
done in this area to prove that the bottle gets the conditions
it needs when sent to the landfill to really, A) trigger,
and B) follow through and biodegrade?
The route of degradation follows the same
basic principles and therefore what works for PE works for
PET, the trick is to get the first stage of oxidation underway,
so again no specific studies have been done with PET but
they have been done on other polymers using the technology
and since the principal is the same it is not unreasonable
to assume the bottle will biodegrade in a landfill.
7. You mentioned about biodegrading in a
marine environment. Have there been any tests on marine biodegradation
done? (There are specific test protocols for this.)
There have not been any specific tests done
with PET in a marine environment but given that in this situation
there is plenty of UV light and often high temperatures then
we have confidence in the oxo-biodegradation process working
well here.
8. What happens if the water bottles have
exposure to extended sunlight or high heat, before the water
is consumed? (such as in a hot car or stored in a trailer
truck)?
The Reverte™ additive package for
PET bottles has been formulated to ensure no degradation
(see explanation above) will occur during the shelf – life
of the product even if exposed to sunlight and heat during
this period.
9. California, USA has passed legislation
that will require plastic containers, utensils, bags that
claim to be “biodegradable” to comply with the
composting standards (the PLA interests pulled quite a coup
there) in order to make the claim.... this means that those
making claims of biodegradability there will face a problem.
It seems that they intentionally targeted biodegradables
there with this legislation, and their studies. Why do you
think they would now make an exception for your oxo-biodegradable
technology? How are you advising customers with California
presence to deal with this, without facing repercussions
there?
We are very aware, indeed we were in there
fighting for oxo-biodegradable technology, about the new
legislation in California but our understanding is that as
long as we use the term oxo-biodegradable and not just biodegradable
then we are OK. We therefore always insist on users of Reverte™ to
avoid the word biodegradable (not only in CA but everywhere)
and instead use oxo-biodegradable which is a term now recognized
by ASTM in the ASTM 6954 Standard Guide.
Our Reverte™ logo incorporates the
clear message of “Oxo Biodegradable” and “Recyclable” |
