PA66 or PA6 molding?

October 28, 2019

The year 2018 will probably go down in the history of the engineering plastics market as that of the polyamide 66 crisis.

As more than known to operators, the shortage of ADN (adiponitrile, a building block in the construction of Nylon 66) caused by the saturation of the few active plants in the world, corresponding to the development of the automotive market in the three-year period 2016-2018, has led to a truly critical situation of both availability and prices.

This has prompted major users of polyamide 66 molds to question alternatives and initiate in-depth technical investigations, particularly in cases of glass fiber-reinforced Nylon. The opinion of independent experts, is that 50 percent of polyamide 66 injection molding applications are replaceable with polyamide 6 injection molding. Going into the technical merits and comparing, for example, a PA66GF30 (Polyamide 66 reinforced 30% glass fiber for injection molding) and a PA6GF30 we can note: The stiffness or rather the elastic modulus of a PA66, is cica 10% higher than that of a PA6, but it is easily compensated for by using a 5% glass reinforcement quota (e.g. PA66GF30 = PA6GF35). The points in favor of PA66 over PA6 unquestionably remain:

  • a higher temperature resistance with continuous resistance at 130 °c versus 100 °c of PA6;
  • superior resistance to hydrolysis and enhanced chemical resistance to oils and glycols;

To the advantage of PA6, however, we find:

  • increased impact resistance;
  • Improved printability that occurs lower temperatures of both raw material and mold with 20% energy savings
  • better aesthetics and less tension and notching effects
  • a considerable economic advantage of about 30% ( - 1 € Kg ) and greater availability on the market.

Other aspects, such as shrinkage, UV resistance and moisture absorption, have often negligible differences, albeit related to the actual degree of crystallinity achieved in molding. Finally, within these families of polymers and the resulting compounds, an important variable is the different degrees of viscosity of the products. Injection molding for example of PA6 at high viscosity in place of PA66 at viscosity, standard can often be more than sufficient for the application observing overall surprising results.

Bear Plast has extensive experience in injection molding PA6 and PA66 in a variety of reinforced and unreinforced types and with different viscosities. Thanks to direct relationships with leading manufacturers, it can offer particularly cost-effective solutions from both technical and commercial sides.

Bear Plast S.r.l

Via Monari, 2 42122 Reggio EmiliaREA RE6563Cap. Soc. 258,000 i.v.Vat No. 00292380359CCIAA 126321

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