By far the largest proportion of single use plastics such as those used in disposable packaging end their lives in landfills or, unfortunately, as litter. Conventional plastics can persist unchanged for many years in such environments. The same items made from plastics utilizing EPI’s proprietary TDPA™ technology safely degrade and biodegrade within a few months to 2 - 3 years in these environments. In landfills, they reduce landfill volume and help maximize capacity utilization and they aid in landfill compression.
While not a solution to littering, degradable plastics help in its management by avoiding accumulation of litter. There are also niche markets for example in agricultural mulch films and as landfill covers where products using EPI technology bring large economic and environmental benefits.
Degradable and biodegradable plastics are defined by ASTM D883-99 as follows:
Degradable Plastic: A plastic designed to undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties that may vary as measured by standard test methods appropriate to the plastic and the application in a period of time that determines its classification.
Biodegradable Plastic: A degradable plastic in which the degradation results from the action of naturally-occurring micro-organisms such as bacteria, fungi, and algae.
Oxo-biodegradation is a two-stage process in which a plastic is first converted by reaction with oxygen to molecular fragments that are water- wettable. Secondly, these smaller oxidized molecules are biodegraded and converted into carbon dioxide, water and biomass, by microorganisms. The rate at which this happens for conventional plastics is very slow, taking decades or even centuries. EPI’s TDPA™ additives are catalysts that accelerate this reaction so that it occurs over a few months to a couple of years.
There are 2 main types of biodegradable plastics: oxo-biodegradable and hydro-biodegradable. Both will first undergo chemical degradation by oxidation and hydrolysis for oxo- and hydro-biodegradable plastics respectively. This results in their physical disintegration and a drastic reduction in their molecular weights. These smaller, lower molecular weight fragments are then amenable to biodegradation.
Hydro-biodegradable plastics tend to degrade and biodegrade somewhat more quickly than oxo-biodegradable ones but the end result is the same – both are converted to carbon dioxide, water and biomass. Oxo-biodegradable plastics are generally less expensive, possess better physical properties and are easier to process on current plastics processing equipment than hydro-biodegradable plastics.
Products made from commodity plastics such as PE and PP can be made degradable by incorporating TDPA™ additives. Some commercial products that have successfully incorporated TDPA™ include carrier bags, garbage bags, sandwich bags, cling film and shrink-wraps.
Information on product requirements such as storage conditions, disposal environment and expected degradation rate will enable EPI to give the best recommendation; TDPA™ additives are manufactured in a range of formulations and incorporated at various concentrations in order to control product shelf life and service life.
Yes, different disposal methods require the use of different TDPA™ formulations specific to the conditions of the disposal environment and the desired degradation performance. EPI can make recommendations for the most suitable formulation.
Yes, in-plant materials (trimmings, scrap, etc.) are normally recycled and commonly practiced amongst EPI’s manufacturers. The usual amount of recycled materials used is about 20% for degradable/biodegradable and 5% for non-degradable end products. This will ensure that quality of the end products is not compromised. Additionally, post-consumer plastics can also be recycled in existing recycle streams provided they have not already started to degrade.
The presence of TDPA™ does not affect processability, output rate or quality of end product and are processed using the same equipment as plastics without the additive.
Prior to the onset of degradation and disposal, products incorporating TDPA™ will have virtually identical performance to those without the additive. Products with TDPA™ are engineered to have a predetermined life and have a designated “use before” date.
EPI’s operates a specialized laboratory that performs a variety of chemical, physical and mechanical tests using standard ASTM test methods on products manufactured with TDPA™ formulations. This ensures that customers receive optimum formulations that perform as specified. Typically, disposal conditions are simulated in QUV weather accelerating equipment and aging ovens and samples from these are tested using plastometers, tensile testing equipment and Fourier Transform Infrared Spectroscopy (FTIR).
The breakdown of TDPA™ incorporated products is triggered by heat, UV light and/or mechanical stress or a combination thereof.
The end products of biodegradation are carbon dioxide, water and biomass. Extensive studies and tests have been conducted by EPI with internationally recognized laboratories and institutions to confirm that they do not leave harmful or toxic residues to the environment.
Yes. TDPA™ additives comply with FDA, EFSA and CFIA requirements in the US, Europe and Canada respectively and are safe for food contact applications.