Nylon 6 or polycaprolactam is a polymer, in particular semicrystalline polyamide. Unlike most other nylons, Nylon 6 Granules is not a condensation polymer, but instead is formed by ring-opening polymerization; this makes it a special case in the comparison between condensation and addition polymers. Synthesis: Reinforced Pa6 Pellets can be modified using comonomers or stabilizers during polymerization to introduce new chain end or functional groups, which changes the reactivity and chemical properties. It is often done to change its dyeability or flame retardance. Nylon 6 is synthesized by ring-opening polymerization of caprolactam. Caprolactam has 6 carbons, hence Nylon 6. When caprolactam is heated at about 533 K in an inert atmosphere of nitrogen for about 4–5 hours, the ring breaks and undergoes polymerization. Then the molten mass is passed through spinnerets to form fibres of Nylon 6 Natural Granules. As a synthetic fibre, PA6 Plastic Pellet is generally white but can be dyed in a solution bath prior to production for different color results. Its tenacity is 6–8.5 gf/D with a density of 1.14 g/cm3. Its melting point is at 215°C and can protect heat up to 150°C on average. Production in Europe: At present, polyamide 6 is a significant construction material used in many industries, for instance in the automotive industry, aircraft industry, electronic and electrotechnical industry, clothing industry and medicine. Annual demand for polyamides in Europe amounts to a million tonnes.