On 27th July a report was published from the Transfercenter fur Kunststofftechnik (TCKT) in Austria, which concluded that there would be no negative effects from the inclusion of oxo-biodegradable recyclate into plastic products intended for outdoor use, such as garden furniture, plastic lumber etc.
The British Plastics Federation has commented that there is no way to be certain that the recyclate is only going to be used in such products and have suggested that such recyclate could get into films used in the building industry. However, TCKT has also considered products made from plastic film in its report dated 17th March 2016 and has likewise concluded that there would be no negative effects. For both reports see http://www.symphonyenvironmental.com/recycling-2/
TCKT said in their 17th March report “it is unlikely that recycled film grades for short-life films (e.g. shopping bags) would be used for long-lasting films applied in the building industry. These long-life films should in any event be made with virgin polymer, or be stabilised to deal with loss of properties caused by the melt-processing and the recycling process, whether or not any pro-degradant additive is present. Such stabilisation would effectively neutralise the effect of any pro-degradant additive.
TCKT continued that “a further consideration is the thickness of the material, which limits the oxygen penetration into the plastic, and therefore reduces the effect of the pro-degradant on the bulk material. Therefore the thicker the material the less susceptible it will be to oxo-degradation. Another factor limiting the availability of oxygen, and therefore reducing the degradation rate substantially, would be the case of films which are used as a lining under concrete or other building materials. Such films will generally degrade slowly, at a similar rate to non-degradable plastics, due to the very limited oxygen availability and the exclusion of UV radiation.”
BPF have also questioned the argument that oxo-biodegradables are the solution to the litter problem, but they are not intended as a solution. Oxo-biodegradables were invented because plastic litter is going to get into the environment despite the best efforts of governments. It is obvious to most people that plastic which degrades in a few months after being discarded is better for the environment than plastic which lies or floats around for decades before degrading. Obvious though it may be, Life-cycle Assessments have been done which prove this point. See https://www.biodeg.org/life-cycle-assessments/life-cycle-assessments-2/