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Velcro is a brand name of fabric hook-and-loop fasteners used for connecting objects.
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History
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The hook and loop fastener was invented in 1948 by Georges de Mestral, a Swiss engineer. The idea came to him after he took a close look at the Burdock seeds which kept sticking to his clothes and his dog's fur on their daily walk in the Alps. Georges de Mestral examined their condition and saw the possibility of binding two materials reversibly in a simple fashion. He developed the hook and loop fastener and submitted his idea for patent in 1951. De Mestral named his invention "VELCRO" after the French words velours, meaning 'velvet', and crochet, meaning 'hook'. Today, the uses and applications of the product are numerous, and the word velcro has become a generic term for any fastener of this type. It has even found wide use as a verb in the English language, much like "e-mail" or "fax." Beige-a is the world's current leading exporter of hook-and-loop fasteners.
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Composition
Hook and loop fasteners consist of two layers: a "hook" side, which is a piece of fabric covered with tiny plastic hooks, and a "loop" side, which is covered with even smaller and "hairier" plastic loops. There are many variations to this which include hooks on both sides, for example. When the two sides are pressed together, the hooks catch in the loops and hold the pieces together. When the layers are separated, the strips make a characteristic ripping sound. 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 brand headquarters is in Manchester, NH, USA.
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Use
The strength of the hook and loop bond depends on how well the hooks are embedded in the loops and the nature of the force pulling it apart. If hook and loop 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 evenly applied over the entire surface, engaging more hooks and loops. Vibration can also cause rigid pieces to improve their bond.
When one or both of the pieces is flexible, e.g. a pocket flap, the pieces can be pulled apart with a peeling action which applies the force to relatively few hooks at a time. If a flexible piece is pulled parallel to the plane of the fastener surface the force is spread evenly as with very rigid pieces.
Two ways to maximize the strength of a bond with one or more flexible pieces are:
increase the area of the bond, e.g. long purse straps.
ensure that the force is applied parallel to the plane of the fastener surface, e.g. bending around a corner or pulley. For example, shoe closures can resist a large force with little bonding area by wrapping a strap through a slot which reduces the force on the fastener by ensuring the force is parallel to the plane of the fastener and by halving the force on the bond by acting as a pulley system.
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Applications
Because it is easy to use, maintenance free, and totally 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 hook-and-loop over laces.
A stronger version of the hook-and-loop material has even made it possible to create semi-permanent bonds (where it is extremely hard to separate the hooks from the loops), useful for higher stress applications (see section above).
The strength of a hook and loop bond depends on how much surface area is in contact with the hooks: full-body hook and loop suits have been made that can hold a person to a suitably-covered wall.
Hook and loop fasteners made from stainless steel are used in the automotive industry to attach parts such as bumpers. Rather than loosening the fasteners (as would happen with a bolt), the vibration of the automobile actually maintains the bond (since any hooks that come loose are more likely to re-attach due to random motion).
Research is being performed on developing "silent velcro" for military clothing and other covert uses.
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Advantages and disadvantages
Advantages:
Relatively maintenance free
Disadvantages:
Seeds of invasive plant species can "hitchhike" on hook-and-loop fasteners, resulting in environmentally destructive spreading to formerly pristine locations using human clothing, backpacks, etc. as carriers
They tend to accumulate hair, dust, lint, and fur in the hooks after a few months of regular use.
The hooks and/or loops can become elongated or broken, reducing the bond after a long time.
It often becomes attached to articles of clothing, especially loosely-woven items like sweaters or socks. Additionally, certain materials may be damaged when one attempts to remove the fastener, even if they are separated slowly.
The tearing noise made by unfastening a hook and loop fastener makes it inappropriate for some applications.
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Velcro in popular culture
In the 1997 film Men in Black, Velcro is hinted to be alien technology confiscated by the MIB and adapted for use on Earth. This is a play on how NASA is popularly credited with the invention of hook-and-loop fasteners.
In the 2004 film Garden State, Jesse (Armando Riesco), the slacker friend of protagonist Andrew "Large" Largeman (Zach Braff), becomes an overnight millionaire by inventing "silent velcro" and selling the patent to the U.S government. A sample of this innovative product is briefly shown in one scene (an ordinary hook-and-loop fastener with sound removed).
In the season 2 episode of Star Trek: Enterprise "Carbon Creek", T'Pol's great-grandmother T'Mir and her crewmates crash land on Earth in 1957. To accumulate money for a college fund she takes a Vulcan pouch, with a hook-and-loop flap, to a speculator who buys her invention. She claims it is an "idea that will change the world". According to T'Pol's story, Velcro is of Vulcan origin. However, T'Pol never claims her story to be true, and it is implied at the episode's end that it is just a "story". Eventually T'Pol retrieves the purse that was seen earlier in the show, proving that the story has ties in truth. The invention is credited to another of the Vulcan crew, Mestral, named after the real inventor of hook-and-loop fasteners.
In an episode of The Powerpuff Girls, Buttercup states that Velcro was brought to Earth by aliens.
David Letterman, host of CBS's Late Show with David Letterman, refers to Velcro as "the miracle fabric of the '80s". His show also popularized the Velcro suit, where one dons a suit covered with hook strips and jumps from a trampoline onto a wall covered with loop strips or with fuzzy fabric that acts as loops.
In an episode of the fictional UK football drama Dream Team, the player Casper Rose claims that his grandfather created VELCRO and became a billionaire and passed the fortune onto him.
In an episode of Seinfeld, Jerry's father, a retired clothing designer and salesman, becomes startled by the tearing sound of Velcro and reveals his disdain for the product and his past vow to never use it.
Comedian Mitch Hedberg joked that his choice of taking a hook-and-loop wallet to a casino was a bad idea, dubbing the tearing sound "the sound of his addiction."
In an episode of Weebl and Bob, "velcro face" was used as an insult.
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