Super glue facts for kids
Super glue, or cyanoacrylate, is the general name for a family of fast-acting adhesives with industrial, medical and household uses. It usually comes in a small tube, and is often sold as "Super Glue" or "Krazy Glue".
They are extremely strong glues. Seven drops of super glue is enough to lift a car. However, the glue is not so good at resisting shear (sideways stress).
There are different versions for medical and veterinary use, developed to be non-toxic and less irritating to skin tissue.
Cyanoacrylate adhesives are sometimes known as instant glues.
Contents
Uses
Medical and veterinary
Cyanoacrylate glue is widely used in human and veterinary medicine. It was in veterinary use for mending bone, hide, and tortoise shell by the early 1970s or before. A cyanoacrylate spray was used in the Vietnam War to reduce bleeding in wounded soldiers until they could be taken to a hospital.
n-Butyl cyanoacrylate has been used medically since the 1970s. In the US, due to its potential to irritate the skin, the U.S. Food and Drug Administration (FDA) did not approve its use as a medical adhesive until 1998 with Dermabond (2-octyl cyanoacrylate). A 1986 independent study suggests that cyanoacrylate can be safer and more functional for wound closure than traditional suturing (stitches). Although cyanoacrylates are widely used for sutureless wound repair, "existing adhesives still lack sufficient adhesion strength to completely replace sutures and staples."
Some rock climbers use cyanoacrylate to repair damage to the skin on their fingertips. Similarly, stringed-instrument players can form protective finger caps (typically, when they lose their calluses due to inactivity or accidents) with cyanoacrylates. While the glue is not very toxic and wears off quickly with shed skin, applying large quantities of glue and its fumes directly to the skin can cause chemical burns.
While standard "superglue" is 100% ethyl 2-cyanoacrylate, many custom formulations (e.g., 91% ECA, 9% poly(methyl methacrylate), <0.5% hydroquinone, and a small amount of organic sulfonic acid, and variations on the compound n-butyl cyanoacrylate for medical applications) have come to be used for specific applications. Three cyanoacrylate compounds are currently available as topical skin adhesives. 2-Octyl cyanoacrylate is marketed as Dermabond, SurgiSeal, and more LiquiBand Exceed. n-Butyl cyanoacrylate is marketed as Histoacryl, Indermil, GluStitch, GluSeal, PeriAcryl, and LiquiBand. The compound ethyl 2-cyanoacrylate is available as Epiglu.
The ester substituent has several effects upon the biocompatibility of the adhesive. Longer side chains result in higher flexibility of the cured adhesive allowing a better match for the flexibility of skin, and can result in a slower release of formaldehyde after curing. Alkoxy-ethyl substituents have also been investigated and have shown some promise as a medical adhesive.
Forensics
Cyanoacrylate is used as a forensic tool to capture latent fingerprints on non-porous surfaces like glass, plastic, etc. Cyanoacrylate is warmed to produce fumes that react with the invisible fingerprint residues and atmospheric moisture to form a white polymer (polycyanoacrylate) on the fingerprint ridges. The ridges can then be recorded. The developed fingerprints are, on most surfaces (except on white plastic or similar), visible to the naked eye. Invisible or poorly visible prints can be further enhanced by applying a luminescent or non-luminescent stain.
Cosmetics
Cyanoacrylate is used in the cosmetology and beauty industry as an eyelash extension glue, or a "nail glue" for some artificial nail enhancements such as nail tips and nail wraps, and is sometimes mistaken for eye drops causing accidental injury (adhesion and/or chemical eye injury).
Niche and hobbies
Cyanoacrylates are used to assemble prototype electronics (used in wire wrap), flying model aircraft, and as retention dressings for nuts and bolts. Their effectiveness in bonding metal and general versatility have made them popular among modeling and miniatures hobbyists.
Cyanoacrylate glue's ability to resist water has made it popular with marine aquarium hobbyists for fragmenting corals. The cut branches of hard corals, such as Acropora, can be glued to a piece of live rock (harvested reef coral) or Milliput (epoxy putty) to allow the new fragment to grow out. It is safe to use directly in the tank, unlike silicone which must be cured to be safe. However, as a class of adhesives, traditional cyanoacrylates are classified as having "weak" resistance to both moisture and heat although the inclusion of phthalic anhydride reportedly counteracts both of these characteristics.
Cyanoacrylate glue is also used frequently in aquascaping both freshwater and marine aquariums for the purpose of securing the rhizomes of live plants to pieces of wood or stone. Thin cyanoacrylate glue has application in woodworking. It can be used as a fast-drying, glossy finish. An oil, such as boiled linseed oil, may be used to control the rate at which the cyanoacrylate cures. Cyanoacrylate glue is also used in combination with sawdust (from a saw or sanding) to fill voids and cracks. These repair methods are used on piano soundboards, wood instruments, and wood furniture. Cyanoacrylate glue is also used in the finishing of pen blanks (wooden blanks for turning pens) that have been turned on a lathe by applying multiple thin layers to build up a hard, clear finish that can then be sanded and polished to a glossy finish.
Some hobby applications call for cyanoacrylate glue mixed with inorganic fillers such as baking soda (sodium bicarbonate) and calcium oxide.
Arrow glues
Cyanoacrylate is used in archery to glue fletching to arrow shafts. Some special fletching glues are primarily cyanoacrylate repackaged in special fletching glue kits. Such tubes often have a long, thin metal nozzle for improved precision in applying the glue to the base of the fletching and to ensure secure bonding to the arrow shaft.
Fencing
Cyanoacrylate is used in fencing to glue the blade wire into the groove of the epee or foil.
Safety
Super glue will stick to human skin instantly, meaning that you can glue your fingers together, or to an object, alternate use to seal small cuts scraps and mild wounds. Never use in deep or puncture wounds.
The glue can also cause chemical burns, and exposed skin should be washed with soap and warm water. Separation can be accelerated by applying vegetable oil near, on, and around the glue. If glue gets in eyes, serious injuries can occur. In any case of adhesives getting in or around the eyes, the eye(s) should be rinsed with lukewarm water for 15 minutes and medical care obtained.
Super glue will burn if it comes in contact with cotton, including cotton clothing, cotton gloves, and cotton swabs. The severity of this reaction can range from a small amount of heat and smoke to starting a fire, depending on the amount of glue and/or cotton involved.
Solvents and debonders
Acetone, commonly found as a fraction of nail polish remover (or at hardware stores in pure form), is a widely available solvent capable of softening cured cyanoacrylate. Other solvents include nitromethane, dimethylformamide, dimethyl sulfoxide, and methylene chloride. Another viable solvent for removing cured cyanoacrylate is gamma-butyrolactone. Commercial debonders are also available, many based on propylene carbonate.
Shelf life
Cyanoacrylate adhesives have a short shelf life. Date-stamped containers help to ensure that the adhesive is still viable. One manufacturer supplies the following information and advice:
When kept unopened in a cool, dry location such as a refrigerator at a temperature of about 55 °F (13 °C), the shelf life of cyanoacrylate will be extended from about one year from manufacture to at least 15 months. If the adhesive is to be used within six months, it is not necessary to refrigerate it. Cyanoacrylates are moisture-sensitive, and moving from a cool to a hot location will create condensation; after removing from the refrigerator, it is best to let the adhesive reach room temperature before opening. After opening, it should be used within 30 days. Open containers should not be refrigerated.
Another manufacturer says that the maximum shelf life of 12 months is obtained for some of their cyanoacrylates if the original containers are stored at 35 to 40 °F (2 to 4 °C). User forums and some manufacturers say that an almost unlimited shelf life is attainable by storing unopened at −4 °F (−20 °C), the typical temperature of a domestic freezer, and allowing the contents to reach room temperature before use. Opening a container while chilled may cause moisture from the air to condense in the container; however, reports from hobbyists suggest that storing cyanoacrylate in a freezer can preserve opened cyanoacrylate indefinitely.
As cyanoacrylates age, they polymerize, become thicker, and cure more slowly. They can be thinned with a cyanoacrylate of the same chemical composition with lower viscosity. Storing cyanoacrylates below 0 °F (−18 °C) will nearly stop the polymerization process and prevent aging.
Images for kids
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Harry Wesley Coover Jr. shortly before being awarded the National Medal of Technology and Innovation by US President Barack Obama in 2010
See also
In Spanish: Cianoacrilato para niños
