Not only is duct tape a staple in an engineer’s home toolbox, it was likely an integral part of Martel College’s build for Beer Bike this past weekend. Thus, a preliminary analysis of a common roll of duct tape – 1.88 in x 20 yd roll of Duck Tape – is the subject of this week’s post. For such a common, seemingly simple material, the environmental impacts are actually a bit difficult to track down, so I will split this into multiple posts to allow for adequate detail.
These articles from How Products are Made and Sweethome’s review of The Best Duct Tape helped me figure out the basic construction of duct tape: a grid of cotton/polyester blend with a polyethylene backing on one side and a rubber-based adhesive on the other. For now, I’ll focus only on the embodied carbon in materials, not manufacturing, transport, and end of life.
Cotton Grid: For simplicity, I assumed the threads were pure cotton (5.9 kg CO2 / ton spun fiber). Counting 20×8 thread count in a square inch of the tape I happen to have at home, the cotton contributes 0.4 g CO2eq to the carbon footprint of duct tape.
Polyethylene Backing: If the tape is approximately 9 mils thick (mil = milli-inch), and I estimate that the polyethylene (LDPE) backing makes up about 20% of the total volume of the tape, 0.07 kg of LDPE are in the roll of duct tape. Assuming ~1.9 kg CO2eq/kg plastic, this represents about 1.5 g CO2eq.
Adhesive: Duct tape uses a rubber-based pressure sensitive adhesive, a substance that is tacky at room temperature and adheres almost any surface with a very small amount of pressure. Without inside industry knowledge, I don’t know enough about the additives to complete a thorough analysis of the adhesive. For this first-round analysis, I’ll estimate that 65% of the total duct tape volume is adhesive that can be modeled as pure rubber; using a number associated with rubber production in Thailand on previously forested land, 0.1 kg rubber represents approximately 1.5 kg CO2 eq.
Cardboard Roll: After measuring the cardboard roll to be about 3” in diameter and 0.25” thick, I estimate about 0.03 kg cardboard are incorporated into the roll. At 3.31 kg CO2eq/kg cardboard, this equates to 0.09 kg CO2eq.
Preliminary Total: Though there is much work still to be done to refine this total estimate, for now I estimate about 1.75 kg CO2eq per roll of duct tape.