Scotch Tape, a name brand adhesive tape used for all sorts of tasks, has a full line of adhesive products. However, the question as to why Scotch tape sticks is still unanswered. There are several theories as to what exactly promotes the adhesive process, but the secrecy of the Scotch Tape formula along with the enigma of adhesion keeps users guessing.
In 1930, 3M engineer Richard Drew invented cellulose tape, a moisture-proof way to seal packages and make small home repairs. Drew’s invention began in the 1920s, when he visited an automotive repair shop, where he saw mechanics attempting to paint a car in two colors. Whenever they peeled off heavy adhesive used to keep the paint separate, they would peel off the paint with it. Therefore, in an attempt to find a softer, less abrasive adhesive, he invented masking tape. By the 1930s, he had adapted masking tape to make see-through tape, called cellulose tape. (See Reference 1)
Scotch Tape has developed since its original invention; 1939 saw the introduction of the “snail,” Scotch’s name for its hand-held tape dispenser. During World War II, Scotch refocused its efforts to aiding in the war, providing tape for assorted problems. Double-sided tape was created in this time. By 1961, Scotch had invented magic tape, a tape with a matte-finish, as well as transparent tape. Advances in tape technology have since allowed for a pop-up tape dispenser, vellum tape and removable tape. (See Reference 2)
Scotch Tape holds together all sorts of materials. It is used in offices and homes around the country for taping documents, sealing crafts, fix holes and all sorts of other uses. (See Reference 2)
Scotch Tape is a pressure sensitive adhesive (PSA). These adhesives can join together, but they cannot be too strong to remain stuck in a roll. There are several levels of PSAs, ranging from a slightly sticky post-it note to the heavy duty duct tape. Adhesives are made of polymers, chain molecules that get tangled together. Chemists use both physical and chemical processes to help change adhesives to bonding agents. Then, when these adhesives or bonding agents are applied to a material, the adhesive must be in enough of a liquid state to spread out. For the varying levels of adhesion, scientists use different physical or chemical processes. Scotch Tape, according to the manufacturers at 3M, is formed using an acrylic polymer. (See Reference 1)
As to why exactly tape sticks, there is no solid answer. Some consider that adhesion is based on the universal property of attraction: if any two materials are jammed close enough together, they will stick. (See Reference 3) Another theory states that bubbles create the adhesion. Although tape feels smooth, it is actually very rough when examined under a microscope. When tape is applied, air bubbles get trapped in the crevices, and whenever pressure is applied, the bubbles swell in volume and act like suction cups. (See Reference 1)