Evaluating the potential for recycling all PET bottles into new food packaging

Abstract

To evaluate the feasibility of recycling all PET bottles into food packaging, realistic estimates of the maximum concentration of contaminants that might be expected in the polymer are needed. To estimate the maximum concentration of a contaminant that might be in PET from the storage of non-food substances, sorption experiments into two types of PET were performed. These test materials were 0.8mm thick amorphous PET (a relative sink for contaminants) and commercial PET bottle wall. Using a commercial shampoo containing 1% lindane (C6H6Cl6), the test materials were stored in contact with the shampoo at 20 and 40 degrees C for 231 days. This commercial shampoo also represents an extreme case because it contains 7% acetone, a solvent which swells PET, further enhancing sorption of chemicals. Additional sorption experiments into PET were performed by preparing solutions of 10% toluene in Miglyol (a fractionated coconut oil), 10% benzophenone in Miglyol, 5% 2-butoxyethoxy ethanol (2-BE) in 50/50 water/ethanol, and 10% methyl stearate in heptane. Sorption data from the shampoo into PET illustrate Fickian behaviour. Specifically, the amount of sorption at room temperature is approximately40 times less than that at 40 degrees C. The amount of lindane sorbed into PET from the shampoo after 231 days was 0.1 and 3.7 mgdm(-2) at 20 and 40 degrees C respectively. These values correspond to 28 and 765 mg kg(-1) on a mass/mass basis. All sorptions are within the ranges measured and published by other authors using surrogate contamination testing schemes. Additionally, actual bottles from recycle bins were analysed for the amout of contamination. Results are discussed in terms of potential consumer exposure to non-food contaminants in food containers made of recycled PET and in relation to the surrogate testing methods recommended by the Food and Drug Administration (FDA) for determining the compatibility of a PET recycling process to produce containers suitable for food-contact use.

Life cycle impact assessment of beverage packaging systems: focus on the collection of post-consumer bottles

“…Further disadvantage of PET is the probably low quality of secondary granulates after multiple recycling, but with suitable technology excellent quality of secondary PET is feasible (Hannemann, 2011). Furthermore, closed-loop recycling of food packaging plastics might be not allowed in some cases due to hygienic issues (EC, 2008b), but recycling of PET in food-grade quality have been already possible (Welle, 2013(Welle, , 2011, even if the rPET flakes contains non-food resources (Begley et al, 2002). Recycled PET content of PET bottles in the EU was around 10% in 2010 (An Vossen, 2010).…”

“…Closed-loop recycling was also taken into consideration since this form of packaging waste treatment is available for the glass, PET and aluminium cans (Begley et al, 2002;Welle, 2013Welle, , 2011. Benefits of closed-loop recycling are analysed by the possible positive effects of the use of secondary materials like the secondary PET granulate compared to the primary granulates.…”

Identification of chemicals, possibly originating from misuse of refillable PET bottles, responsible for consumer complaints about off-odours in water and soft drinks

“…Sorption and desorption of both food components and nonfood chemicals have been extensively studied, e.g. by Nielsen (1994) and Begley et al (2002). The effect of washing parameters on the removal of sorbed compounds has also been studied in order to optimize the cleaning process .…”

A Survey of Regulatory Aspects of Food Packaging

“…Because the model tends to overpredict sorption (see appendix), FDA's experimental sorption results and data from the literature have also been used to calculate the sorption of several surrogates into PET under these use conditions (Begley et al, 2002, andDemertzis et al, 1997). The FDA has used a mathematical model, based on Fick's law of diffusion, to predict the amount of a contaminant (represented by the surrogate contaminants described above) that will sorb into a PET bottle during a period of one year at 25 C, the shelf life and use temperature of a typical non-food substance packaged in PET (see appendix).…”