It is prepared by heating caprolactum at 523-533 K in an atmosphere of N2 for about 4 hurs.
It is known as Nylon-6 because the monomer caprolactum contains six carbon atoms
It is obtained by condensation polymerisation of hexamethylene diamine, adipic acid.
hexamethylene diamine H2N(CH2)6NH2
Adipic acid: HOOC-(CH2)4-COOH
As both the monomers have 6 carbon atoms each, the polymer is called Nylon 66.
Nylons are used in the preparation of dress materials.