Polymer Additives for Odor Control In Polymer Recycling Processes

written by Emily Best, North America Marketing Manager, Built-In

Reduce, reuse, recycle. We’ve all heard this phrase before. Recycling programs are a common part of the daily dialogue and behavior patterns of many people around the world. Whether it’s consumers utilizing at home recycle containers, public spaces offering options to recycle next to waste receptacles, or commercial companies seeking to manufacture products made from recycled materials; the recycle movement is here to stay.

In seeking to keep up with the sustainability movement, manufacturing companies are putting increased emphasis on end-of-product-life recycling. Companies are conducting research and approving capital investment in recovery, cleaning, and sorting technologies. Increased formulations research is leading to innovations in compatibilizing additives that enhance polymer properties and allow use of hard-to-separate polymer blends like polyethylene and polypropylene.

What’s That Smell?

One challenge that polymer material recyclers face is the odor issue. Recycled polymers...well they can be quite smelly. In a recent study, one scientist describes the various odors in post consumer plastic waste as moldy, cheesy, or acidic. The reason that these odors present themselves is due to different types of substances that migrate into the polymer molecules before the plastic recycling process begins, such as cleaners, cosmetics, and food. Think about all of the polymer containers and products that a person can toss into the recycling bin in a day’s time, like empty food containers or hair product bottles. If those polymer containers aren’t washed or rinsed before they land in the recycle bin, they arrive at the recycling plant with all of that carbon matter built up and likely congealed onto their surfaces.

The cleaning processes at recycling plants are imperfect, like most processes, and oftentimes the recycled polymer materials come out at the end of the cleaning process with leftover residue and dirty microbes still present and thriving within the polymer molecules and on the surface of the polymer material. Additionally, these cleaning processes are commonly very low temperature washing systems without enough heat to actually kill any existing bacteria.

Polyolefins in particular are very susceptible to picking up smells because their molecular chains are less dense than other materials, allowing for smelly contaminants to enter the material and be absorbed. Demand for odor control technologies to address the scent in post consumer plastic scrap is on the rise, and many companies are making investments to address the issue, such as purchasing and installing new equipment with specialized odor removal systems.

Scentry® for Polymers is a ground breaking technology by Microban that eliminates odors in recycled plastic products. Click here to learn more.

Enhancing The Polymer Recycling Process With Polymer Additives

The team here at Microban® has developed several polymer additives to address the issue of odor in polymers. Antimicrobial technology is very useful in polymer recycling for several reasons and reduces the noxious odors that are present. For recycled materials that are processed at very low temperatures, such as recycled foam that are then added to binders for making carpet underlayment, there might still be viable microbes left in the materials, such as bacteria, fungal spores, and yeast. In this case, an incorporated antimicrobial additive brings a benefit to the recycled foam by preventing residual microbes from surviving and growing. Next, recycled materials may be highly contaminated by organic materials, such as food, sugars from soda syrups, dirt, feces, etc. During processing, these organic residues are often not removed or destroyed by heat and stay in the materials as organic content. In some materials, presence of organic content can encourage microbes to survive and attack the materials because the residual organic content acts as a potential food source for microbes.

Recycled materials are frequently regarded as inferior to virgin materials. Materials enhanced with Microban polymer additives stay fresher and last longer. The added value and superior durability enhancement of the recycled material provides polymer recyclers with a unique selling point when incorporating these powerful additives into their manufacturing process. The Microban team utilizes a customized approach with our partners when it comes to odor control for recycled polymer materials. We work with you to consider the material, the processing conditions, specific microbial issues, and the end uses of the recycled material such as food contact products.

Learn more about Microban polymer additives for recycled polymers today.