Nylon 66 (loosely written nylon 6-6, nylon 6/6, nylon 6,6, or nylon 6:6) is a type of

polyamide A polyamide is a polymer with repeating units linked by amide bonds. Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk. Artificially made polyamides can be made through ...

nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...

. It, and

nylon 6 Nylon 6 or polycaprolactam is a polymer, in particular semicrystalline polyamide. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring-opening polymerization; this makes it a special case in the compar ...

, are the two most common for textile and plastic industries. Nylon 66 is made of two monomers each containing 6 carbon atoms,

hexamethylenediamine Hexamethylenediamine is the organic compound with the formula H2N(CH2)6NH2. The molecule is a diamine, consisting of a hexamethylene hydrocarbon chain terminated with amine functional groups. The colorless solid (yellowish for some commercial sam ...

and

adipic acid Adipic acid or hexanedioic acid is the organic compound with the formula (CH2)4(COOH)2. From an industrial perspective, it is the most important dicarboxylic acid: about 2.5 billion kilograms of this white crystalline powder are produced annuall ...

, which give nylon 66 its name. Aside from its superior physical characteristics, nylon 66 is attractive because its precursors are inexpensive.

Synthesis and manufacturing

Hexamethylenediamine Hexamethylenediamine is the organic compound with the formula H2N(CH2)6NH2. The molecule is a diamine, consisting of a hexamethylene hydrocarbon chain terminated with amine functional groups. The colorless solid (yellowish for some commercial sam ...

(top) and

(bottom), monomers used for

polycondensation In polymer chemistry, condensation polymers are any kind of polymers whose process of polymerization involves a condensation reaction (i.e. a small molecule, such as water or methanol, is produced as a byproduct). Condensation polymers are for ...

of Nylon 66.

Nylon 66 is synthesized by

of hexamethylenediamine and adipic acid.

Equivalent Equivalence or Equivalent may refer to: Arts and entertainment *Album-equivalent unit, a measurement unit in the music industry * Equivalence class (music) *'' Equivalent VIII'', or ''The Bricks'', a minimalist sculpture by Carl Andre *''Equiva ...

amounts of hexamethylenediamine and adipic acid are combined in water. In the original implementation, the resulting ammonium/

carboxylate In organic chemistry, a carboxylate is the conjugate base of a carboxylic acid, (or ). It is an ion with negative charge. Carboxylate salts are salts that have the general formula , where M is a metal and ''n'' is 1, 2,...; ''carboxylat ...

salt was isolated and then heated either in batches or continuously to induce polycondensation.n(HOOC - (CH2)4 - COOH) + n(H2N - (CH2)6 - NH2) -> OC - (CH2)4 - CO - NH - (CH2)6 - NH - n + (2n - 1)H2O Removing water drives the reaction toward polymerization through the formation of amide bonds from the acid and amine functions. Alternatively, the polymerization is conducted on a concentrated aqueous mixture formed of hexamethylenediamine and adipic acid. It can either be extruded and granulated at this point or directly spun into fibers by extrusion through a

spinneret A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. Spinnerets are usually on the underside of a spider's opisthosoma, and a ...

(a small metal plate with fine holes) and cooling to form filaments.

Applications

In 2011 worldwide production was two million tons. At that time, fibers consumed just over half of production and engineering resins the rest. It is not used in films due to its inability to be oriented. Fiber markets represented 55% of the 2010 demand with engineering thermoplastics being the remainder. Nylon 66 is frequently used when high mechanical strength, rigidity, good stability under heat and/or chemical resistance are required. It is used in fibers for textiles and carpets and molded parts. For textiles, fibers are sold under various brands, for example

Nilit NILIT Ltd. (Hebrew: נילית בע"מ) is a privately owned, international manufacturer of nylon 6.6 ( polyamide) fibers headquartered in Migdal HaEmek, Israel. NILIT specializes in the polymerization, spinning and texturing of nylon 6.6 yarns ...

brands or the

Cordura Cordura is a collection of synthetic fiber-based fabric technologies used in a wide array of products including luggage, backpacks, trousers, military wear and performance apparel. Originally developed and registered as a trademark by E.I. ...

brand for luggage, but it is also used in airbags, apparel, and for carpet fibres under the Ultron brand. Nylon 66 lends itself well to make 3D structural objects, mostly by injection molding. It has broad use in automotive applications; these include "under the hood" parts such as radiator end tanks, rocker covers, air intake manifolds, and oil pans, as well as numerous other structural parts such as hinges, and ball bearing cages. Other applications include electro-insulating elements, pipes, profiles, various machine parts,

zip tie A cable tie (also known as a hose tie, zip tie, or tie wrap) is a type of fastener for holding items together, primarily electrical cables and wires. Because of their low cost, ease of use, and binding strength, cable ties are ubiquitous, findi ...

s, conveyor belts, hoses, polymer-framed weapons, and the outer layer of turnout blankets. Nylon 66 is also a popular guitar nut material. Nylon 66, especially glass fiber reinforced grades, can be effectively fire retarded with halogen-free products. Phosphorus-based flame retardant systems are used in these

fire-safe polymers Fire-safe polymers are polymers that are resistant to degradation at high temperatures. There is need for fire-resistant polymers in the construction of small, enclosed spaces such as skyscrapers, boats, and airplane cabins.Zhang, H. ''Fire-Safe Po ...

and are based on

aluminium diethyl phosphinate Aluminium diethyl phosphinate is a chemical compound with formula Al()3. It decomposes above 300 °C. Applications In the family of dialkyl phosphinic acid salts, aluminium diethyl phosphinate has been found to be an excellent flame retar ...

and synergists. They are designed to meet

UL 94 UL 94, the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing, is a plastics flammability standard released by Underwriters Laboratories of the United States. The standard determines the material� ...

flammability tests as well as Glow Wire Ignition Tests (GWIT), Glow Wire Flammability Test (GWFI) and

Comparative Tracking Index The Comparative Tracking Index (CTI) is used to measure the electrical breakdown (tracking) properties of an insulating material. Tracking is an electrical breakdown on the ''surface'' of an insulating material wherein an initial exposure to elec ...

(CTI). Its main applications are in the electrical and electronics (E&E) industry.

References

{{Reflist Polyamides Plastics Synthetic fibers Synthetic materials amides

Synthesis and manufacturing

Applications

See also

References