Polylactide (PLA) Frequently Asked Questions
What is PLA, and what are you making with PLA?
PLA is polylactide, a resin derived from corn byproducts. NatureWorks PLA is the domestic supplier of the PLA resin we use, and their brand of PLA is called IngeoTM. It is a transparent resin that can be injection stretch blow molded in virtually all of the molds we use for PET (polyethylene terephthalate) bottles and jars. Right now, we are making several sizes of vitamin packers using Ingeo PLA from NatureWorks. We are also working with leaders in biopolymer research to investigate “next-generation” PLA blends that incorporate other all-natural additives such as cotton, clay and minerals that add thermal stability and enhance the barrier characteristics of the PLA.
What are the environmental benefits of PLA?
PLA is made from corn, a renewable resource. Unlike petroleum-based plastics, the corn used to make PLA can be grown every year – and can be grown domestically. The PLA resin also requires significantly less energy to make compared to petroleum-based plastics, and PLA bottles are blow molded at lower temperatures than PET and HDPE (high-density polyethylene) bottles, which requires less energy.
What kinds of products are most appropriate for PLA? Will my products have compatibility issues?
PLA is best-suited for products that are oil-based or products that are not negatively affected by moisture vapor transmission. It is also a good option for products that have a relatively short shelf life (12 months or less) and which are not stored in or transported through hot and humid environments. We always suggest that our customers perform their own compatibility tests any time they move into a new resin.
I heard PLA won’t work for most water-based products. What are the H20 barrier characteristics of PLA?
Compared to PET, PLA’s moisture vapor transmission rate is about 10 times higher. This means that if your product has high moisture content, the H20 in your product can escape through the packaging over time; conversely, if your product attracts moisture, water vapor can get into the bottle over time.
Which of your products are available in PLA?
Most of the stock products we make in PET can also be made from PLA, however we do not stock any PLA bottles or jars. If there is a particular item that you would like us to run in PLA, talk to your sales representative about the products you are interested in and the annual volumes you will need. You will want to perform compatibility tests to make sure your product works in PLA, and we’ll provide pricing based on your volumes. We may also have to make new base plates for the PLA bottles or jars that have the SPI code “7” on the bottle to indicate this bottle cannot be recycled in the PET recycling stream.
My test bottles ran fine and my compatibility tests were good. What do I do now?
In order for Alpha to obtain the NatureWorks PLA resin needed to make your bottles, your company will need to apply for a resin allocation from NatureWorks. NatureWorks uses the information you provide to forecast the amount of resin they need to produce each quarter, and how the PLA resin is being used in commercial applications. Our Sales Representatives can assist you with this process.
Should I be concerned about the supply of PLA?
According to NatureWorks, they have added capacity for the Ingeo PLA resin and can produce about 300 million pounds of PLA resin per year at its current facilities. Alpha has been assured by NatureWorks PLA that our customers will be able to get PLA resin that has been allocated to them so long as that customer has provided realistic projections for annual usage. We will work with you to determine exactly how much resin you should request in order to meet your production volumes.
Is PLA recyclable? Is it biodegradable?
PLA is compostable, which means it breaks down to negligible organic materials within a relatively short time frame under industrial composting conditions. For example, it would take approximately 47 days for a typical disposable cup made of NatureWorks PLA to compost into carbon and water. (Actual days can vary depending on the shape and thickness of the item.) Industrial composting conditions mean that a sustained level of heat and humidity are maintained, and mature compost with microbes are present; compost piles in individuals’ back yards do not produce these same results. PLA resin is NOT biodegradable.
What’s the cost of PLA compared to other conventional plastic resins?
Based on NatureWorks’ published prices, the cost for PLA resin is between 10% and 15% higher than PET (recycle code #1) and also considerably higher than HDPE (recycle code #2), but with the price of petroleum-based resins subject to fluctuations tied to oil prices, this changes frequently. It is conceivable that PLA will eventually be priced similarly to PET and HDPE, however that depends greatly on the supply of PLA, as well as the future price of petroleum-based resins. PLA bottles may also include new base plates, set-up charges and purge fees for small orders, which add to the cost of manufacturing.
What is the minimum number of PLA bottles I can buy?
Currently, Alpha requires a minimum run of 50,000 units for all packaging made from PLA. Orders may also be subject to a set-up fee and purge charge.