In the past several issues of Label & Narrow Web I've tried to encourage you to develop habits and practices when using pressure sensitive label materials that will improve our environment. If I've caused just one of you to stop and think about material selection, material design and material disposal then I believe I've been successful. I want to finish this year by introducing a material development which supports my eco-economy philosophy. It's pretty new, cutting edge so to speak, and while it has a way to go to commercial success, it certainly justifies our attention.
First, several housekeeping chores: I'm a bit worried that my column on EBAs (environmentally benign adhesives) might have been too confusing and deserves a bit more clarification. In last month's column I celebrated the use of EBAs in the postage stamp application. I want to make sure that I didn't leave you with the impression that the only pressure sensitive adhesives that can be successfully removed in the repulping process have to be similar to the EBAs used with postage stamps; far from it. There's a lot of technology that continues to be considered in making PSAs friendlier. The adhesive used for the United States Postal Service stamp is certainly the most visible and successful application. However, as with anything, there are different degrees of success. If we take concentrated quantities of matrix, even though the converter is using PSA with EBA formulations, we will be unable to disperse those adhesives in the repulping process. In other words, today paper mills that recycle can handle envelopes with PSA stamps but not concentrated volumes of matrix.
Keep in mind that screening PSAs is part of the solution. For a PSA to be screenable, the particles need to be large. Research indicates that high tack adhesives improve screenability. The adhesive tends to cling together and the particles are large enough to be caught by the screen.
Another idea to improve the recyclability of pressure sensitive adhesives is to add wet strength to the face paper. In this case it is much more difficult to repulp the face stock. The adhesives cling to the face stock and make the screening process more successful.
So there are a variety of measures under evaluation. The point is to explore as many options as possible with your material supplier in an attempt to create a friendlier pressure sensitive label.
I also want to share with you a thought that I've come across several times in the last few months. It has to do with the difference between urban legend and myth. As I understand, urban legend is about an activity that is alleged to be true but can't be easily verified. Myths are pretty similar because there is no verification, although myths express some kind of belief about how our world really works.
If you can get past these definitions you'll appreciate a new book by New York author and trash sleuth Elizabeth Royte. The book is Garbage Land: On the Secret Trail of Trash. Wonderful! Is this the subject of urban legend or myth? Royte wonders if it is better for the environment to throw a tissue in the wastebasket or flush it down the toilet; trust me, only in New York, well, maybe California, too. For months she follows trash around New York proving and disproving what is truly best for the tissue, or rather us. That's the urban legend/myth part. Her conclusions, however, are worth noting:
"I came around in a full circle to think more about upstream… If you think it's bad in the dump, take a look upstream at how much waste is generated in manufacturing… The focus on individual action is misguided; we need to look bigger and farther upstream, beyond ourselves."
How true. All of our focus needs to go back to design, conception. Formulations are critical. It is up to you to want and to ask for greener and more environmentally friendly materials. It all starts with the message we send in the kind of identification technology we use. This brings me, finally, to the subject of this month's column, the new non-petrochemical resin: polylactic polymer.
Polylactic acid, or PLA, is a compostable, clear resin made from corn, a renewable resource. PLA is a biopolymer manufactured under the trade name Natureworks PLA. Natureworks is owned by Cargill, the world's largest private company and also the world's largest grain merchant.
What started as a joint venture with Dow Chemical is now 100 percent Cargill. Natureworks consists of a huge factory in Nebraska, USA, which is corn country, with manufacturing capability of 300 million pounds of resin per year. There are a variety of applications for the resin, from textile to packaging to containers and even shoes. The strongest selling point is environmental. It takes less fossil fuel energy to produce equal amounts of finished goods than it does using petroleum based resins. It produces less carbon dioxide than petroleum does, even after you factor in the tractor diesel fuel and fertilizer used by corn farmers.
In our industry we have been introduced to PLA films by Plastic Suppliers of Columbus, OH, USA. They have trademarked their PLA product under the name of Earth First.
Earth First applications include label film, window carton film, floral wrap film, and envelope film. Plastic Suppliers even suggests that its film will work in shrink sleeve and wraparound film applications. The physical and mechanical values are competitive with most petrochemical films. Along with the environmental advantages, this new product seems likely to make headway in our industry.
I am aware of several large material suppliers manufacturing finished laminate with this film. The advantages include the possibility of down-gauging, more stable pricing than petrochemical based film, and less environmental impact from both a manufacturing and disposal point of view. I am also aware that successful silicone coating trials, utilizing UV curable silicones, have occurred.
This is the kind of material development that we need to make our industry more eco-economic. I'm not advocating that PLA resins should replace petrochemical resins. I am suggesting that where design permits, the use of PLAs will demonstrate our commitment to a better environment.
I'm not sure if the Europeans would consider PLA a "genetically modified" petrochemical. I wonder what they thought about Dolly, the cloned sheep. Regardless of your views, consider this: a PLA facer, with an EBA glue, and a recyclable release liner. Now we're getting somewhere.