Each year in UK , we trash billions of paper cups, no you are not guilty for this, these are takeaway cups and are supposed to be trashed, and although these cups are 99% bio-degradable and 100% recyclable, there is still some scope to improve on that, because recycling PE coated paper products require a slightly more time to disintegrate than un-coated paper, this is so because paper cups are lined with a thin coat of the common plastic or polyethylene ( PE ) to prevent leakage and mush.
Polyethylene is in itself safe for humans, is heat resistant and doesn’t harm us in any way, but it’s presence in cups make the cup’s slightly difficult to degrade naturally, for the qualities of polyethylene that make the cups usable now prevent them from absorbing moisture and getting decomposed by bacteria present in the soil.
Although the cups we produce are as we mention always, are 99% biodegradable and are 100% recyclable, the ink and the PE gets separated from the paper as part of the recycling process, but re-pulping of recycled cups require some special attention than what is required for un-coated paper.
In recent times, there are emerging new technologies that have the potential of bridging the gap between 100% biodegradable and 99% biodegradable. Scyphus is gearing up to implement mineralised resin alternatives to 100% PE extrusion coating that are 100% biodegradable, these are mixed grade paper barrier alternative to PE and are made of 40% traditional PE resin mixed with 60% Calcium Carbonate, the mixture is blended and can be extruded and coated on any of the paper products like paper cups using the same machinery used in coating 100% PE.
The mineral mixed grade coating fragments into dense particles that are easily removed as part of the recycling process and easily removed as part of the recycling process.
Better and truly 100% Compostable Alternative – PLA
Although mineralised resin is considered a safer alternative, but there had been other alternatives that existed much ahead of this mineralised resin alternative, and this alternative is not a very new one. It is PLA, Polylactic Acid, more commonly known as Bioplastic.
PLA has seen a variety of applications including medical implants, 3D printing, injection molding, film and sheet casting, and in our industry specific application, extrusion coating.
As discussed above, PE doesn’t prevent the paper from decomposing, but itself not being biodegradable, if not separated using special processes during recycling, the PE in a natural composting environment, would fragment instead of actually disintegrating, and although these fragments are often microscopic, they retain their plastic character and can result in accumulation of plastic in environment and have serious ecosystem consequences.
Scyphus paper cups has finally taken a logical step towards moving from PE to PLA instead of mineralised resin. Although PLA has its own problems of developing cracks easiler than PE, and thus providing lower insulation and a slight loss in the leak proof character, it is nevertheless the way to go if we want to keep living on this earth for a few more years.
PLA is compostable and do not require a separation process at recycling plants, and even if the cups end in landfills, there are no chances of microscopic plastic reaching our ecosystem, PLA made from corn starch or sugar cane will easily decompose and degrade into nature.
The only other problem with PLA, other than its slightly lower strength and resistance, is in the fact that it is not a perfect material for extrusion coating, and most manufacturers would not change all machinery to produce a new paper, but that has now been researched and solution found, PLA-based coatings can be successfully processed on traditional PE lines when modifications are made to the formulation to improve melt strength and elongational viscosity.
Coming back to the issues of strength and insulation of PLA as compared to PE, the modified PLA bio cups have been tested in comparison with traditional PE coated paper cups, and an article on how modern application of PLA performs at par with PE can be found here.