I been reading for some time now, that the plastics industry is wanting to make changes to the resin ID code found on many plastic bottles. Not being a plastic’s engineer but a recycler, the resin code (those single digit numbers found in a chasing arrows triangle on many bottles) was my first introduction to the major types of plastics and the differences in their behavior.
Our business learned that PET (#1) and the PEs (HD #2 & LD #4) don’t mix happily and PP (#5) is better off left out of the mix of PEs but is highly recyclable. PS (#6), where found on containers has been as difficult to recycle as “OTHER” (#7), which doesn’t represent a specific resin nor any of the above. Some of the white solid Styrofoam can now be recycled, reusing packing peanuts has long been common.
Our business grew up right alongside the developing industry for recycling plastics and teaching at community fairs, state conferences and to school kids about looking for the resin recycling code on bottles and recycling them was how we paid back society for making the essence of our business (materials made from recycled content) possible.
We learned about the incompatibility of PP with the PEs when we became involved in a project for an oil museum in Kuala Lumpur Malaysia, located in the Petronas Twin Towers. The designer wanted bullnose edges made from our Origins Cool Blue color material on the kiosks and these kiosks were also to be surfaced in that same Origins material. Carving out bullnose edges in solid PE would have been expensive and the resulting appearance, showing the inside of a panel of the appropriate thickness would have looked quite a bit different than the surface characteristics of the thin laminate.
There were three cabinet shop subcontractors but the bullnose edge detail made all of them nervous, for they did not have technical experience with the Origins material and its behaviors. So, our firm elected to do that particular part of the fabrication. There were 3 sizes which required 3 heavy metal molds. We set up a work space with an electric winch for hoisting the molds into a water bath, after the plastic was heated to softness on a silicone strip heater.
The nature of Origins fabrication is that it results in a conglomerate, rather than a homogenized material (which extrusion creates). In our curved forms, PP did not melt or merge with the PE and that is how we discovered that PEs are better off without PP in our resin mix. Ultimately, except for a few, what we define as “market” colors, we settled on a controllable, single resin process for creating the colors we stock and are the basis of our various color formulas. You can view some of the Origins colors at this link – Origins Color Chart.
For probably two decades at least, the resin recycling code has been crucial to the effort to recycle plastic bottles and reduce the load on landfills as well as extending the life of a petroleum product that gets only minimal use in its original incarnation. One of the issues was a misinterpretation of the “chasing arrows” that was initially used, which could be understood as indicating either that the object was made of recycled plastic or that the plastic that it was made from was recyclable, neither of which were factually accurate. It was decided that a simple triangle should replace the chasing arrow symbol on new molds for plastic objects.
Even though abbreviations such as PET, HDPE and PP are now fairly commonplace in addition to the familiar numbers within a triangle symbol, they do not begin to fully describe the complexities of modern day plastics. So, the ASTM International standards group is considering adding extensions to those abbreviations to further identify variations and characteristics within the seven major resin groups. There is a Resin Identification Code subgroup, which has had responsibility for the coding system since 1988. The Resin Identification Code was originally developed by the Society of the Plastics Industry, a trade group.
Some of the information that could be conveyed by a new coding system might be the melt flow, the temperature at which a plastic begins to melt and flow. Some plastics require a high temperature and some require very little heat. The process of making changes in the Resin Identification Code, which began in 2010, is not being rushed. The group is seeking consensus among its members.
Previously, I had the impression that the entire Resin Identification Code system was going to be abandoned; and I was concerned about how much educational value would be wasted. I do know that some of the base level plastics recyclers have brought a lot of technology into their processes to produce cleaner and more consistent material for use by companies such as ours, so that was not a huge concern, but more like a sadness at the thought of losing an old friend.
I am grateful that the ASTM members backed away from that idea, in favor of modifying the existing standards. I currently agree that more information needs to be included on #7 OTHER objects to allow for a greater possibility of those being recycled, rather than trashed in a landfill. In China, there are more than 100 numbers used to identify different combinations which in the US became #7s.
Any changes to the resin code will require the approval of 37 of our 50 states, because these have legislation on their books related to the Resin Identification Code. Even the switch away from the chasing arrows requires approval in some states. It is hoped that details will be finalized by the middle of 2015 but that time frame might have to stretch into 2016 because of the review process.
Even though the Resin Identification Code is definitely useful to the reclaimer there is definite concern that the consumer is not left confused by the changes. The cooperation of consumers in recycling plastics is important enough, that even though there is a need for greater clarification within the industry, the working group is also carefully considering the impact of any changes on environmentally conscious households and the momentum for recycling that is already active.
Information Resources –
2014 – Resin ID codes could get upgraded – http://www.plasticsnews.com/article/20140110/NEWS/140119989/resin-id-codes-could-get-upgraded
Blog author ~ Deborah Hart Yemm is co-founder of
Yemm & Hart, a green materials producer