Phthalates and bisphenols: challenge in plastic recycling.

Plastics are fundamental in our daily lives, but their environmental impact and the challenges associated with their recycling are topics of growing concern. In particular, phthalates and bisphenols, chemical additives commonly used to improve the properties of polymers, have attracted attention regarding their regulation due to their harmful effects on health and the environment. This article will address the nature of these compounds, their use in plastics, the challenges they present, existing regulations and possible solutions for their recycling.

What are phthalates?

Plastics phthalates, known as phthalic acid esters, constituyen un grupo de más de 80 compuestos que se utilizan principalmente como plastificantes en diversas industrias, mejorando la flexibilidad y durabilidad de los plásticos. Se encuentran en una amplia variedad de termoplásticos, como el PVC, PE y PP. Sin embargo, la migración de ftalatos desde los envases plásticos hacia los alimentos, el agua y el aire ha generado inquietudes, dado que estos compuestos no se adhieren químicamente a los polymers..

General chemical structure of phthalates. R and R' = CnH2n+1; n = 4-15

And bisphenol?

There are several types of bisphenols, but the best known is bisphenol A (BPA). BPA is used in the manufacture of durable epoxy resins and strong, clear polycarbonate plastic. In the past, it has been used in food contact materials, such as reusable food storage containers and linings in metal food cans, to reusable baby bottles and bottles.

Furthermore, in 2019, a study carried out by experts from the Granada Biosanitary Research Institute detected the presence of BPA in the ink of purchase receipts. It was verified that 90% of tickets or receipts, in which the ink fades over time, known as 'thermal paper', contain this compound.

Like phthalates, the main concern with bisphenols is the leaching of BPA, especially at high temperatures, which can have adverse effects on human health and the environment.

Impact of phthalates and bisphenols

What are the real effects of these additives on polymers? The impact of these compounds is considerable, affecting both human health and the environment.

Exposure to phthalates and bisphenols has been shown to pose significant health risks, including adverse effects on the reproductive and endocrine system, toxicity to organs such as the kidney and liver, as well as a potential increased risk of cancer. This exposure can occur through oral, respiratory or dermal routes.

In addition to their harmful effects on humans, phthalates and bisphenols can contaminate water and soil. This can happen due to the leakage of plastic products into unregulated and illegal landfills and during recycling processes, where small amounts of plastic can be lost and end up in the environment. This pollution has the potential to alter aquatic and terrestrial ecosystems, affecting natural balance and wildlife.

Challenges in plastic recycling

The main challenge that companies dedicated to plastic recycling face is the management and treatment of compounds such as Bisphenol A and phthalates, since these are not eliminated during conventional mechanical recycling processes, which causes them to remain in the recycled plastic.

Consequently, when creating a new product with that recycled plastic , these compounds will be integrated into the final product. If such a product is used to package food, there is a risk that the compounds migrate from the packaging to the food. This makes it difficult to determine the composition of a recycled plastic or the additives it “carries over from its previous lives.”, so it is crucial to exercise caution in the applications in which it is used.

Our solution is to implement our decontamination technology, whose objective is eliminate odors and volatile organic compounds (VOCs) in recycled polymers. In this way, we manage to eliminate these chemical compounds from plastic during the recycling process, preventing them from migrating and coming into contact with people or the environment.

Regulations on phthalates and bisphenols

Facing the challenges related to phthalates and bisphenols, it has been considered crucial to establish regulatory policies to ensure responsible use and protect human health and the environment.

In the European Union, regulations have been implemented to evaluate and restrict chemical risks in collaboration with the European Chemicals Agency (ECHA).On the one hand, since 1999, the EU has established restrictions on some phthalates in toys and baby items.

Table 1. Phthalates subject to restrictions in the European Union.

PHTHALATE	CAS No.	ACRONYM
Bis(2-ethylhexyl) phthalate	117-81-7	DEHP
Dibutyl phthalate	84-74-2	DBP
Benzylbutyl phthalate	85-68-7	BBP
Diisononyl phthalate	68515-48-0	DINP
Ftalato de diisodecilo	68515-49-1	DIDP
Di-n-octyl phthalate	117-84-0	DNOP
diisobutyl phthalate	84-69-5	DIBP

As we can see in table 1,these include DEHP, DBP, BBP, DINP, DIDP, DNOP and DIBP, with a maximum allowed concentration of 0,1% in the polymeric material.

On the other hand, the use of Bisphenol A in plastic bottles for infants was prohibited in 2011and its use in thermal paper was prohibited in 2020.Although its use has been authorized until recently in food contact plastics, finally the Law 7/2022, of April 8, on waste and contaminated soils for a circular economy includes a restriction on the use of bisphenol A and phthalates in packaging, in order to promote the reduction of the content of dangerous substances in materials and products.

Conclusion

Plastics phthalates and bisphenols They represent a significant challenge for the use of recycled plastic and for the transition towards the circular economy in the sector. But it is not an insurmountable obstacle. With technological innovations and appropriate policies, we can move towards a more sustainable and secure future. It is essential that everyone, from manufacturers to consumers, recognize these challenges, regardless of the regulatory policies and technological solutions related to these compounds, and collaborate in finding solutions.