PA 6

Thermoplastics > Polyamides

Polyamide 6 - PA6 - poly(caprolactam)
Polyamide 6 is one of the most used polyamides due to the good availability of the raw material (caprolactam), the wide range of applications and the ease and economic viability of the production, transformation and recycling of this polyamide. It is characterized by excellent mechanical properties, wear resistance, low coefficient of friction, a high melting point, good impact resistance and high resistance to fatigue. Polyamides 6 can be easily molded and used to produce a wide range of colored polymers, and have a good fiber reinforced surface. Reinforced with fiberglass polymers is characterized by a high level of rigidity, good dimensional stability, excellent heat resistance, good wear resistance and a low coefficient of friction. Its melting point is 217-223 ° C, and it has excellent impact resistance, especially for conditioned parts, and is softer than PA 66. The molding cycles are short and solutions through the composition with reinforcements such as fibers Glass or carbon, glass beads, mineral fillers such as kaolin, talc or wollastonite can obtain degrees with a wide distribution of physical-mechanical and thermal properties. They can be mixed with ABS, PP with a specific compatibilizer or other polyamides such as PA66 for their appearance and to improve the thermal properties or with PA11 and PA12 to improve the impact resistance. The copolyamides 66/6 and 6/66 have properties very similar to their equivalent homopolymers with the exception of the melting point, which is lower in copolyamides. It is possible to obtain copolyamides with a melting point significantly lower than the equivalent homopolymer based on the percentage of initial monomers.
Nombres - Símbolo			Formula
Polyamide 6 - PA6 Poly (caprolactam) Poly (hexane-6-lactam) Poly (6-aminohexanoic acid) Poly (hexamethylene adipamide) Poly [imino (1-oxohexane-1,6-diyl)] Registration number CAS 25038-54-4 Chemical formula (C6H11NO) n
Properties PA6
Good mechanical resistance High impact resistance Good cushioning characteristics Good sliding properties Less corrodes the metal of the screws or inserts Good chemical resistance Color with the pigment or masterbatch Inherently UL94 V2
Physica and mechanical properties PA6
The amide groups are very polar and can be joined to make them through hydrogen bonds. These bonds determine the tenacity, the resistance to temperature and the form of elasticity. However, if water molecules propagate within the polymer structure by binding to the molecular chains, they cause the reduction of intermolecular bonds and increase the mobility of the molecules. The absorbed molecules, therefore, act as plasticizers and reduce the elastic modulus and the tensile strength and flexural strength, increase the toughness of the polymer, which makes it less brittle and changes the glass transition temperature (Tg ) at lower values.
Thermal properties PA6
PA 6 is rated for continuous use at temperatures up to 250 ° F (121 ° C) with an operating temperature below -40 ° F (-40 ° C). It has a very high tensile strength, good chemical and abrasion resistance, and a low coefficient of friction. Most nylon grades have some UL 94 flame rating.
Polimerization PA6
The caprolactam ring opens in the presence of water (hydrolysis), the linear molecules are grouped together (polyaddition) and produce a macromolecular chain whose length depends on the presence of a chain terminator (for example, an acetic acid). The molten polymer is extruded through a plate with holes (spinner), which produces cylindrical granules. Given the equilibrium situation of the polyaddition reaction, the conversion of caprolactam to PA 6 is from 89 to 90%. The rest is formed by monomer and cyclic oligomers. These oligomers must be removed by extraction with hot water, that is, by washing the chips in a countercurrent flow of demineralized water. The moisture present in the chips at the end of the extraction process (between 10 and 15% of water) is eliminated with a flow of hot nitrogen. The purity of the nitrogen must be very high, since PA 6 is very sensitive to oxygen.
Products range PA6
PA6 is offered in a wide variety of grade including no filler / no reinforcement, as well as grade that contains fiberglass, mineral filler, hybrid 2 or goes fuller, with special additives and special lubricant, modified impact and retardant call.
Processability PA6
PA6 is suitable for all transformation systems common to thermoplastics. As a result of absorbing moisture from the atmosphere or conditioning in water, they become more stubborn and resistant to abrasion, and the elastic modulus decreases. In fact, PA 6, if kept in air at 23 ° C and with a relative humidity of 50% at saturation, absorbs 1.7% of moisture, and at 23 ° C and with 100% relative humidity to the saturation, absorbs up to 5.7% humidity, according to ISO 62. The hygroscopicity of a polyamide is linked to the polarity of the amide groups. In polyamides, in fact, the nitrogen attached to the nitrogen has a weak positive charge, since the nitrogen atom is much more electronegative than the hydrogen atom, and once attracted by the negative charge of oxygen in the water molecule, it forms a hydrogen bridge link. The carbonyl group that forms weak bonds with the hydrogen present in the water molecules is also present. For this reason, nylon 6 granules need de-humidification before being processed. To produce products with excellent physical, mechanical and aesthetic properties, a moisture content of less than 0.08% (800 parts per million or ppm) is generally required in the polyamide 6 granules loaded with 30% starting glass fibers.
Applications PA6
PA6 has a wide and general use in automotive air supply, air supply manifolds, transmission systems, pedal box, gear mechanics, pulleys, wheels, rail profiles, threaded rods, clutches, tension chains , motors, covers of air ducts for printed by the swelling, airbag containers, external grids, door handles, wheel covers, mirrors, electricity and electronics, electrical panels of low voltage power distribution, connectors, industrial connections, terminal blocks, the switch of electrical components, the industry in general, tool electrical housings and internal components, sports ski bindings, inline skates, shock absorbers, railway wheels, trucks, various mobile applications, off-piping Shore, packaging films, textile spinning.