NYLON

It is said that, during the Second World War, when Japan impeded USA from importing silk from China, the Dupont Company, one of the most important US chemical industry, created a new material to produce military parachutes and called it NYLON, acronym of NOW YOU’VE LOST, OLD NIPPON! Maybe it is only a legend but Nylon, technically known as Polyamide, has been for decades – and it will be continue to be so – an irrepaceable material for many and specific applications in Engineering Plastics field.
In the polymerisation process, starting monomer is the caprolactam, obtained from phenol or cyclohexane. Through the reaction of a chemical intermediate, obtained by addition of water, the ring of caprolactam is broken and a reactive acid is produced. Polymerisation process takes place in an autoclave with water, at a temperature of 250° - 270°, using a salt of PA66 or aminocaproic acid as initiator. Mono-functional monomers can be added to check molecular weight and the industrial reaction takes place continuosly or discontinuously
Thanks to its excellent features, Nylon is widely used for making machine parts. Due to its extraordinary combination of physical properties such as hardness, toughness, abrasion and chemical resistance, as well as lightness and high impact strenght even at low temperatures, Nylon is regularly used instead of other materials in mechanical industry.

Advantages

Mechanical tests carried out in laboratories – such as impact strenght - point out that, the addition of glass fiber at 30% to Nylon 6 and the use of the same thermal stabilise, after an ageing at a temperature of 150° C and 170° C, improve the decrease of value compared to the room temperature.
At a temperature of 190° C, after an ageing of 3000 hours, impact strenght value is not measurabe anymore. After 3000 hrs, at temperatures of 150° C, 170° C and 190° C, also tensile modulus shows considerable improvements and increases by 350 MPa. Compared to PA66, PA6 has more other advantages: it is cheaper and more suitable for injection moulding. Furthermore PA6 is more isotropic, less corrosive to metal of the screws, easier to weld, thanks to its good impact strenght, it is also easier to machine.

Main features

  • Among Polymers, PA6 has the best mechanical, even at high temperatures and in challenging environments.
  • PA6 presents a good toughness, high tensile, compressive and impact strength.
  • Nylon has low coefficients of friction and a good resistance to abrasion; no lubricanti s required because PA6 a self-lubricating material.
  • Polyamide is quite resistant to oil, grease, ageing and weathering effects; it is not concentrated acids resistant. It absorbs the moisture as well.
  • Nylon has an excellent fatigue strenght, its features remain unchanged under repeated efforts.
  • High moisture absorption.

Technical application

  • Mechanical: Thank to its properties and features, Nylon is widely used in the mechanical industry. It is used to make pulleys, cams, bearings, gears, dampers, sliding guides, wheels and so on.
  • Alimentary: In accordance with current regulations (UE and FDA), Nylon is suitable for food contact.
  • Chemical: Nylon resists to inorganic compounds, to solvents and to alkalis; it does not resist to acids.
  • Thermal: PA6 maintains its properties up to 90° C, after this limit mechanical features start to decrease.
  • Electrical: Because of its inclination to absorb moisture from surroundings, Nylon is not suitable for use in electrical applications.

Defects

Polyamides are hygroscopic materials. The value of hygroscopicity – it can vary from 3,5% (with a moisture content equal to 65%) to 100% (with a moisture content equal to 100%) – have to be taken into consideration for the determination of dimension of pieces because it affects mechanical, electrical and dimensional features. Nylon can be attacked by strong acids. PA6 is more absorbent than PA66, it is softer and more sensitive to hydrolysys too. From 70° C Nylon starts to depolymerize.

Applications

Toothed wheels, bushings, pulleys, cams, bearings, dampers, mandrels, feeders for pumps and piston valves, cochleas, electrical isulators, parts of pumps, rotors and so on.

Shapes

icona-tondo-p

RODS

∅ 8 - 350 mm
icona-tubo-p

TUBES

O.D. 25-400 mm
icona-lastre-p

SHEETS

Spes. 8 - 100 mm

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