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 throug ...

nylon Nylon is a family of synthetic polymers characterised by amide linkages, typically connecting aliphatic or Polyamide#Classification, semi-aromatic groups. Nylons are generally brownish in color and can possess a soft texture, with some varieti ...

. 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 compari ...

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

hexamethylenediamine Hexamethylenediamine or hexane-1,6-diamine, 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 f ...

and

adipic acid Adipic acid or hexanedioic acid is the organic compound with the formula C6H10O4. It a white crystalline powder at standard temperature and pressure. From an industrial perspective, it is the most important dicarboxylic acid at about 2.5 billion ...

, 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 or hexane-1,6-diamine, 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 f ...

(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). Natural proteins as well as s ...

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 Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged (cationic) polyatomic ion, molecular ion with the chemical formula or . It is formed by the protonation, addition of a proton (a hydrogen nucleu ...

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

salt was isolated and then heated either in batches or continuously to induce polycondensation. : (2n-1) 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 ar ...

(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 film applications as it cannot be biaxially 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, nylon 6.6 (polyamide) fibers headquartered in Migdal HaEmek, Israel. NILIT specializes in the polymerization, spinning (textiles), spinning and ...

brands or the

Cordura Cordura is a brand of synthetic fiber-based fabrics used in products such as luggage, backpacks, trousers, military wear, and performance apparel. Cordura was developed and trademarked by E.I. du Pont de Nemours and Company (DuPont) in 192 ...

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 Injection moulding (U.S. spelling: injection molding) is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals (for ...

. It has broad use in automotive applications; these include "under the hood" parts such as

radiator A radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

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, panduit, tie wrap, wire tie, zap-straps, or zip tie) 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, ca ...

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 retardant with halogen-free products. Phosphorus-based flame retardant systems are used in these fire-safe polymers 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 retard ...

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 standardization, standard released by Underwriters Laboratories of the United States. The standard determi ...

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

Synthesis and manufacturing

Applications

See also

References