Technical Questions & Answers on Reverte™ in PET Plastic bottles

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 eco-friendly technology, about the new legislation in California (which we believe is flawed) but our understanding is that as long as we use the term eco friendly then we are OK. We therefore always insist on users of Reverte™ to avoid the word Oxo-Biodegradable (not only in CA but everywhere) and instead use the Reverte branding.