| Today I will start a series about plastics. I plan to share information with you so you can make the best decisions for your products and your customers! Recycling is of big importance to many of us, as well as to our customers. That being said, sometimes we don’t know about different plastics and which plastics are best used in each of our own applications. So, let’s talk about plastics and recycling!
We are going to start at the beginning of the list with plastics recycling number 1. PET or PETE both are acronyms for the same plastic, polyethylene terephthalate. (pol-ee-eth-uh-leen tuh-ref-thuh-leyt) I find that to be a definite mouthful! Are you ready to begin? Polyethylene terephthalate is actually polymerized units of the monomer ethylene glycol mixed with terephthalic acid, which in plain English is saying that the low weight molecules of have been mixed together and been made to be bigger and heavier by the evaporation of water! So… where can we find PET being used? PET is used most commonly used in bottles and jars, as well as plain packing tape! PET is a common container material in the food and cosmetics industry because PET is an excellent barrier material, preventing the rapid transfer of molecules. This means that sodas retain their carbonation, foods or cosmetics won’t oxidize and products with a high water or alcohol content won’t evaporate as quickly. PET is one of the most recycled plastics, but in the USA only 30% of PET containers were recycled in 2012! In 2011, approximately 7.5 million tons of PET were collected and 5.9 million tons of usable PET flake were produced after cleaning. That is a staggering number that I can barely comprehend! All PET containers can be recycled and reused to make new containers, polyester fabric, sleeping bag insulation and even carpet! The demand for recycled PET products is rapidly increasing and yet because the supply is limited preventing a rapid growth in the recycled plastics industry. |
 Recycling symbol for PET plastics.  PET Water Bottles. |
That being said, what are the pros and cons for you using PET containers for your products?
Pros:
- Easily recycled
- Comes in a variety of shapes and colors.
- Low transmission rates between inside and outside of container slows oxidation and evaporation of products.
- The best way to sanitize is to dip in water/Hydrogen Peroxide solution containing 3% Hydrogen Peroxide and allow to air dry.
- Easily recycled around the world.
- Shatterproof and ideal for slippery bathrooms!
Cons:
- PET has a low heat tolerance. If a product is poured in when too hot, the contain will warp. This also means products can’t be heated in the PET containers.
- If sanitized with a Hydrogen Peroxide solution as listed above, water marks can be left on the containers as they dry.
I hope I didn’t bore you today! Check back in tomorrow for the next plastics on our list, HDPE (High-density polyethylene) and MDPE (Medium-density polyethylene)!
“Polyethylene terephthalate is actually polymerized units of the monomer ethylene terephthalate…” That is not correct. PET is (usually) made by polymerizing the monomer ethylene glycol AND terephthalic acid. Terephthlic acid will react with both ends of the ethylene glycol. If we call the ethylene gycol ‘A”, and the terphthalate ‘B’, then we have BAB. Each B however, can react with ethylene glycol again, so that leads to ABABA. The ‘A’ can still react with the B’s, so that leads to BABABAB ad so on and so on.
Thank you for catching that! I will fix the blog!
I am wondering if you can respond to this by email:
I store photographic developers in these PET plastic bottles, as they are much less likely to shatter than glass. Film developer, which is prone to being destroyed by oxidation, is kept well in these easily obtained bottles but there is one thing that disturbs me. Over a long period, like a year or more, there is slightly less liquid in the bottle due to very slow, gradual evaporation.
Can I greatly slow down this evaporation by storing filled PET plastic bottles in sealed food storage bags with most of the air removed? It would seem to me that if air immediately outside the bottle were not as ‘available’ to absorb liquid, the evaporation from the contents of the bottle would not be as likely. Is this sound reasoning, or do you have a better way to maintain the integrity of the liquid stored for long periods in PET plastic bottles? – David Lyga
What types of plastic is used when you buy this material from the manufacturer? You may need to find a plastic that has an extra step of processing to make it less permeable.
Tina