Velcro

This article is about the fabric fastener. For other uses, see Velcro (disambiguation).

Velcro hooks

Velcro loops

Velcro is a company that produces the first commercially marketed fabric hook-and-loop fastener, invented in 1948 by the German electrical engineer George de Mestral. De Mestral patented Velcro in 1955, subsequently refining and developing its practical manufacture until its commercial introduction in the late 1950s.

The word Velcro is a portmanteau of the two French words velours ("velvet"), and crochet ("hook").

Hook-and-loop fasteners consist of two components: typically, two lineal fabric strips (or, alternatively, round "dots" or squares) which are attached (e.g., sewn, adhered, etc.) to the opposing surfaces to be fastened. The first component features tiny hooks; the second features even smaller and "hairier" loops. When the two components are pressed together, the hooks catch in the loops and the two pieces fasten or bind temporarily. When separated, by pulling or peeling the two surfaces apart, the velcro strips make a distinctive "ripping" sound.

The first Velcro sample was made of cotton, which proved impractical and was replaced by Nylon and polyester. Velcro fasteners made of Teflon loops, polyester hooks, and glass backing are used in aerospace applications, e.g. on space shuttles.

Variations on the standard Velcro hook and loop fasteners include hooks on both faces, buttons, zippers, laces, and buckles.

George de Mestral's patent expired in 1978, but the term Velcro is a registered trademark in most countries. Generic terminology for these fasteners includes "hook and loop", "burr" and "touch" fasteners. The Velcro company headquarters is in Manchester, New Hampshire, USA.

History

Tiny hooks can be seen covering the surface of this burr. The design of Velcro imitated this natural mechanism for seed dispersion.

The hook-and-loop fastener was conceived in 1941 by Swiss engineer, Georges de Mestral who lived in Commugny, Switzerland. The idea came to him one day after returning from a hunting trip with his dog in the Alps. He took a close look at the burrs (seeds) of burdock that kept sticking to his clothes and his dog's fur. He examined them under a microscope, and noted their hundreds of "hooks" that caught on anything with a loop, such as clothing, animal fur, or hair. He saw the possibility of binding two materials reversibly in a simple fashion if he could figure out how to duplicate the hooks and loops. This inspiration from nature or the copying of nature's mechanisms (called bionics or biomimesis) is viewed by some like Steven Vogel or Werner Nachtigall as a key example.

Originally people refused to take him, and the idea, seriously when he took his idea to Lyons, which was then a center of weaving. He did manage to gain the help of one weaver, who made two cotton strips that worked. However, the cotton wore out quickly, so de Mestral turned to synthetic fibers. He settled on nylon as being the best synthetic, which had several advantages. Nylon doesn’t break down, rot, or attract mold, and it could be produced in threads of various thickness. Nylon had only recently been invented, and through trial and error he eventually discovered that, when sewn under hot infrared light, nylon forms hooks that were perfect for the hook side of the fastener. Though he had figured out how to make the hooks, he had yet to figure out a way to mechanize the process, and to make the looped side. Next he found that nylon thread, when woven in loops and heat-treated, retains its shape and is resilient; however, the loops had to be cut in just the right spot so that they could be fastened and unfastened many times. On the verge of giving up, a new idea came to him. He bought a pair of shears and trimmed the tops off the loops, thus creating hooks that would match up perfectly with the loops in the pile.

Mechanizing the process of weaving the hooks took eight years, and it took another year to create the loom that trimmed the loops after weaving them. In all, it took ten years to create a mechanized process that worked. He submitted his idea for patent in Switzerland in 1951 and the patent was granted in 1955. Within a few years he obtained patents and began to open shops in Germany, Switzerland, Great Britain, Sweden, Italy, the Netherlands, Belgium, and Canada. In 1957 he branched out to the textile center of Manchester, New Hampshire in the United States. Columnist Sylvia Porter made the first mention of the product in her column Your Money's Worth of August 25, 1958, writing "It is with understandable enthusiasm that I give you today an exclusive report on this news: A 'zipperless zipper' has been invented — finally. The new fastening device is in many ways potentially more revolutionary than was the zipper a quarter century ago." A Montreal firm, Velek, Ltd., acquired the exclusive right to market the product in North and South America, as well as in Japan, with American Velcro, Inc. of New Hampshire, and Velcro Sales of New York, marketing the "zipperless zipper" in the United States.

De Mestral obtained patents in many countries right after inventing Velcro as he expected a high demand immediately. Partly due to its appearance, though, Velcro's integration into the textile industry took time.^{[citation needed]} At the time, Velcro looked like it had been made from leftover bits of cheap fabric, and thus was not sewn into clothing or used widely when it debuted in the early 1960s. It was also viewed as impractical.

De Mestral saw Velcro as a replacement for zippers, among other things.

A number of Velcro brand products were displayed at a fashion show at the Waldorf-Astoria hotel in New York in 1959, however the fabric got its first break when it was used in the aerospace industry to help astronauts maneuver in and out of bulky space suits. However, this reinforced the view among the populace that Velcro was something with very limited utilitarian uses. The next major use Velcro saw was with skiers, who saw the similarities between their costume and the astronauts, and thus saw the advantages of a suit that was easier to don and remove. Scuba and marine gear followed soon after. After seeing astronauts storing food pouches on walls, children's clothing makers came on board. As Velcro only became widely used after NASA's adoption of it, NASA is popularly — and improperly — credited with its invention. By the mid-1960s Velcro was used in the futuristic creations of fashion designers such as Pierre Cardin, André Courrèges and Paco Rabanne.

Later improvements included strengthening the filament by adding polyester.

In 1978 de Mestral's patent expired, prompting a flood of low-cost imitations from Taiwan, China and South Korea onto the market. Today, the trademark is the subject of more than 300 trademark registrations in over 159 countries. George de Mestral was inducted into the national inventors hall of fame for his invention.

The big breakthrough George de Mestral made was to think about hook-and-eye closures on a greatly reduced scale. Hook and eye fasteners have been common for centuries, but what was new about Velcro was the scale of the hooks and eyes. Shrinking the hooks led to the two other important differences. Firstly, instead of a single-file line of hooks, Velcro has a two-dimensional surface. This was needed, because in decreasing the size of the hooks, the strength was also unavoidably lessened, thus requiring more hooks for the same strength. The other difference is that Velcro has indeterminate match-up between the hooks and eyes. With larger hook and eye fasteners, each hook has its own eye. On a scale as small as that of Velcro, matching up each of these hooks with the corresponding eye is impractical, thus leading to the indeterminate matching.

Strength

The hooks on a piece of Velcro

The loops on a piece of Velcro

Velcro is strong enough that a two inch square piece is enough to support a 175-pound (79 kg) person. The strength of the bond depends on how well the hooks are embedded in the loops, how much surface area is in contact with the hooks, and the nature of the force pulling it apart. If Velcro is used to bond two rigid surfaces, e.g. auto body panels and frame, the bond is particularly strong because any force pulling the pieces apart is spread evenly across all hooks. Also, any force pushing the pieces together is disproportionally applied to engaging more hooks and loops. Vibration can cause rigid pieces to improve their bond. Full-body Velcro suits have been made that can hold a person to a suitably covered wall.

When one or both of the pieces is flexible, e.g. a pocket flap, the pieces can be pulled apart with a peeling action that applies the force to relatively few hooks at a time. If a flexible piece is pulled in a direction parallel to the plane of the Velcro surface, then the force is spread evenly as it is with rigid pieces.

Three ways to maximize the strength of a bond between the two flexible pieces are:

• increase the area of the bond, e.g. using larger pieces of Velcro
• ensure that the force is applied parallel to the plane of the fastener surface, e.g. bending around a corner or pulley.
• increase the number of hooks and loops per area unit.

Shoe closures can resist a large force with only a small amount of Velcro. This is because the strap is wrapped through a slot, halving the force on the bond by acting as a pulley system (thus gaining a mechanical advantage), and further absorbing some of the force in friction around the tight bend. This layout also ensures that the force is parallel to the Velcro strips.

Advantages and disadvantages

In favor of Velcro, it is easy to use, safe, and maintenance free. There is only a minimal decline in effectiveness even after many fastening and unfastenings. The tearing noise it makes can also be useful against pickpockets.

Velcro has several deficiencies: it tends to accumulate hair, dust, and fur in its hooks after a few months of regular use. The loops can become elongated or broken after extended use. Velcro often becomes attached to articles of clothing, especially loosely woven items like sweaters. Additionally, the clothing may be damaged when one attempts to remove the Velcro, even if they are separated slowly. The tearing noise made by unfastening Velcro makes it inappropriate for some applications. For example, a soldier hiding from the enemy would not want to alert the enemy to his position by opening a Velcro pocket. It also absorbs moisture and perspiration when worn next to the skin, which means it will smell if not washed.

Textiles can contain chemicals or compounds, e.g. dyes, that may be allergenic to sensitive populations. Velcro products have been tested according to the Oeko-tex certification standard which imposes limits on the chemical content of textiles to address the issue of human ecological safety.

Applications

A shoe using Velcro closures

NASA astronaut Greg Chamitoff ponders his next move with a Velcro-modified chess set on board the ISS. Also visible up and to the left are bare Velcro pads for affixing

Because it is easy to use, maintenance free and safe, the hook-and-loop fasteners have been used for just about every conceivable application where a temporary bond is required. It is especially popular in clothing where it replaces buttons or zippers, and as a shoe fastener for children who have not yet learned to tie shoelaces and for those who choose Velcro over laces. Velcro is used in adaptive clothing, which is clothing designed for people with physical disabilities, the elderly, and the infirm who may experience difficulty dressing themselves due to an inability to manipulate closures, such as buttons and zippers. As Velcro is easier to manipulate, it makes a good replacement.

Velcro held together a human heart during the first artificial heart surgery, and it is used in nuclear power plants and army tanks to hold flashlights to walls. Cars use it to bond headliners, floor mats and speaker covers. It is used in the home when pleating draperies, holding carpets in place and attaching upholstery, among many other things. It closes backpacks, briefcases and notebooks, secures pockets, and holds disposable diapers, and diaper covers for cloth diapers, on babies. It is an integral part of the game tag rugby, is used in surfboard leashes and orthopaedic braces.

NASA makes significant use of Velcro. Each space shuttle has ten thousand inches of a special Velcro made of Teflon loops, polyester hooks, and glass backing. Velcro is used everywhere, from the astronauts' suits, to anchoring equipment. In the near weightless conditions in orbit, Velcro is used to temporarily hold objects and keep them from floating away. A Velcro patch is used inside astronauts' helmets where it serves as a nose scratcher. During mealtimes astronauts use trays that attach to their thighs using spring and Velcro fasteners.

The US Army is another big user. It uses Velcro fasteners on combat uniforms to attach name tapes, rank insignia, shoulder pockets for unit patches, skill tabs, and recognition devices, such as the infrared (IR) feedback American flag. They also had a silent version of Velcro developed for use with Army soldier uniforms, as the ripping sound could betray a soldier's position. A new version was created which reduced the noise by over 95%. The manufacturing process to create this noiseless Velcro is, however, a military secret.

RFID attached with Velcro

There have been some failed uses for Velcro as well. One such failure was a worm collar that consisted of a cylindrical strip that fishers were supposed to slip over their live bait. The Velcro was supposed to snag in the teeth of striking bass.

Variations on Velcro

Slidingly Engaging Fastener was developed to address several problems with velcro. Heavy duty variants (e.g., "Dual Lock" by 3M) feature mushroom shaped stems on each face of the fastener, providing an audible snap when the two faces mate. A strong adhesive backing adheres each component to its substrate.

See also

• Adaptive clothing
• Biomimicry
• Metaklett

External links

• Velcro Official US company website
• closeup of Velcro hooks and loops
• VELCRO Patent - from Google Patents Anniversary