However those techniques often left a sticky residue on the paint that was difficult to remove. Sometimes, it would even mean the painters had to do the entire paint job over again.
One of Drew's responsibilities at 3M was to deliver samples of sandpaper to local automotive shops for testing, where he often overheard workers who were painting complain about the problems with tape used for these paint jobs.
The twenty-three year old then lab assistant got the idea to create a new tape that would create a seal so that the paint wouldn't get through and yet also come off clean without leaving any sticky residue that ruined the paint finish. Drew used the adhesive that 3M utilized in the construction of its sandpaper as a starting point. From there, it took him two years of experimentation with different types of adhesives that he applied to a crepe paper backing to come up with the right combination.
Thus, what would be called "Scotch" Masking Tape was born in In , his position as technical director at the fabrication laboratory allowed him to pursue another idea. Cellophane had recently been invented by DuPont and was being used by grocers and bakers as a neat way to package their groceries.
However, there wasn't a good way to seal the cellophane with tape because the colored backing ruined the clear look. So Drew and his team of inventors worked to create a tape that used this clear cellophane as a backing.
Unfortunately, the machinery that 3M used in order to apply the adhesive to the cellophane backing tore the material, and the glue that worked for the masking tape appeared amber on the clear cellophane. Gradually, Drew's team overcame these difficulties. They designed machinery that prevented splits and breaks. Instead of standard masking tape adhesive, they developed a new, nearly colorless one made from oils, resins, and rubber which helped keep the cellophane transparent.
They found that using a primer helped the adhesive hold evenly along the backing. On September 8, , 3M sent its first roll of cellophane tape to a prospective client, who enthusiastically endorsed it. DuPont had developed a heat-sealing process for cellophane, greatly reducing the demand for tape as a commercial package sealer.
It was also the first full year of the Depression, a seemingly bad time to introduce a new product. Almost daily, new ideas sprang up for using the tape to make old things do. It was used to mend book pages, sheet music, window curtains, and even small rips in clothing. Bankers used it to repair paper currency. Secretaries found it perfect for patching broken fingernails.
Farmers discovered they could use it to seal cracked eggs. Housewives used it to cap canned milk, remove lint from clothing, secure bait on mousetraps, and repair cracked ceiling plaster. Goodyear used the tape to cover the inner ribs and beams of its dirigibles, creating an anti-corrosive shield. As a result, 3M prospered and was one of the few companies in the world that didn't lay off employees during the Depression.
In the years ahead, 3M would continue responding to consumer demand, developing numerous specialized tapes for household and industrial use.
The company developed more than types of tape to solve war production problems, such as sealing and labeling parts. Rubber shortages during the war prompted 3M to switch to synthetic acrylate adhesives. Although not as strong, acrylate adhesives retained their clarity and actually aged better than rubber-based adhesives, which turned yellow and brittle over time.
It's estimated that transparent tapes are used in more than 90 percent of American homes. The tape that Dick Drew conceived so many years ago has been to the moon as insulation on a lunar lander , featured on Saturday Night Live, and immortalized in fine art. But Drew, who died in at age 81, never gave up trying to find something better.
Yet despite his many successes, which led to his induction into the National Inventors Hall of Fame, Drew never forgot how a bit of sandpaper changed his life. All pressure-sensitive tapes share two common, but deceptively simple, traits: They all have some sort of adhesive attached to a backing.
Yet to make this dynamic duo work requires as many as 30 raw materials and a bit of complex chemistry. Certain portions of distillate from crude oil are chemically reacted to form the desired raw materials.
These materials are combined in water or a hydrocarbon solvent in carefully controlled proportions and are polymerized to form the final adhesive product. As for the cellulose acetate backing, its manufacture begins with wood pulp or cotton linters.
These cellulose fibers are broken down by chemical and physical means to their basic fiber structure. A plasticizer is added to the cellulose acetate, which is then formed into sheets of film. Finally, the surface of the film is treated to give it a matte finish. The finished film is wound up in large rolls, ready to be coated with adhesive.
Once the adhesive and backing are ready, several steps are required to produce a roll of tape. First, the cellulose acetate film is surface treated. One side of the film is treated with a release coating, which makes the tape easy to unwind. The other side is treated with a primer that ensures good anchorage of the adhesive film. A thin coating of pressure-sensitive adhesive is metered onto the film and dried.
The adhesive-coated tape is wound up to form a large jumbo roll. The jumbo roll is then split into narrow bands, which are wound on individual cores to produce the retail or commercial size rolls of tape.
While the tape itself worked great once it was applied, getting it off the roll wasn't easy. The end had to be picked loose with a fingernail or other sharp instrument. Once free, the tape didn't stay that way for long. Invariably, the loose end would curl back into place on the roll, become virtually invisible, and hard to locate.
Frequently, the tape tore before the desired length was cut. Even if users succeeded in getting the right amount of tape, it had to be cut off with scissors or torn haphazardly, a time-consuming and awkward task.
As a result, tempers flared and complaints rolled in. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options.
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