A Story of Tape

In spite of its ubiquity, most of us have not thought much about tape nor know very much about it. There are different sources of information. One source is the information on uses that is included on the tape label. Books are another source of information. For example, Henry Petroski’s The Evolution of Useful Things traces how 3M company engineers developed “scotch tape” drawing on what they learned from making wet sanding paper. Petroski’s description of how “post-its” were developed raises the question of whether “post-its” should be considered as “tape”. He also introduces the idea that some applications demand tape that doesn’t stick too well.

Petroski describes the burgeoning auto industry of 1925 as filled with environmental hazards. For example, fine sanding the painted cars threw fine dust from lead based paints into the air to be breathed by assembly line workers. Wet sanding was needed, but existing sand paper dissolved when used with water. Minnesota Mining and Manufacturing developed a product to be tested in the St Paul auto shops. While delivering the test product a young technician, Richard Drew, overheard other problems. Two tone painting had become popular, but the ways of masking painted areas usually damaged the surface they were supposed to protect. Drew went back to the laboratory to develop an adhesive that wouldn’t stick too tightly, allowing it to be dispensed from a roll and to peel off cleanly from an auto body.

Acceptable combinations of adhesive and backing were not easy to come by. He struggled for two years with the problem and against suggestions that he drop the tape project. By chance he found some left over crepe paper, tried it, and found its crinkly surface ideal for the adhesive. Eureka! Masking Tape!

A new technology is no sooner in use than its shortcomings become evident: masking tape is not water proof, thus does not work well in high moisture situations. While Drew was working on the problem of a tape that tolerated moisture, cellophane began to be used as a packaging material. He tried it as the backing for his adhesive. The first attempts didn’t meet his design criteria: “It lacked proper balance of adhesiveness, cohesiveness, elasticity and stretchiness. Furthermore it had to perform in temperatures of 0 degrees to 110 degrees F in humidity of 2 to 95 percent.” It took a year to develop

an acceptable product: cellophane or “scotch” tape. Once in use, its deficiencies became apparent: the tape yellowed with age, curled up, oozed adhesive, and it was almost impossible to find the end on the roll of tape. The last problem spawned the industry of tape dispensers. For many years, however, the other problems went unsolved. That’s just the way “scotch” tape was. Small improvements were made through the years, but there was no tape that addressed the problems of cellophane tape until 3M developed its Scotch Magic Transparent Tape many years later.