DSM Engineering Plastics

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Trading places: Can PPA sustainably and cost-effectively replace PA66?

  • Tim Vorage · Global Market Development Manager ForTii at DSM Engineering Plastics

  • 11 September 2018

The supply chain of polyamide 66 (PA66) has experienced significant challenges over the last year or so, and will most likely last another year at least. Since the challenges are structural in nature, some analysts argue that supply chain challenges for this material will continue for several more years, or maybe even be the new normal. This leaves manufacturers searching for sustainable, cost-effective solutions for their applications. Polyamide 6 (PA6) and polyester (PBT) are often considered, and for good reason. Are there other materials that would be a suitable alternative to PA66?

Some designers and engineers may wonder if polyphthalamide (PPA) is a suitable alternative to PA66. The short answer is that it depends on the application. To explain further, PPAs with a low glass transition temperature of 70°C to 100°C often contain 60% to 70% PA66 by weight on a polymer basis. These materials would therefore not be a good alternative considering the current PA66 supply challenges. PPAs with a high glass transition temperature contain very little PA66, or may not contain PA66 at all. These materials could be considered as an effective alternative to PA66, depending on the part performance and costs.

First, since the shrinkage of the materials differs – affecting specifications on dimensional accuracy and stability – and processing temperatures for the melt and mould are higher for PPA than PA66, a check on both of these factors is necessary to determine if PPA can be an alternative material for your application.

Next, let’s take a closer look at performance requirements. If your design is based on strength below 70°C dry as moulded, than PA6 and PBT may prove better and more cost-effective solutions, since the glass transition temperature of PA66 is around 70°C. If your design is based on an operating temperature of 50°C in humid conditions (for example, a relative humidity of 50% to 100%) or for operating temperatures of 80°C to 120°C (dry as moulded or in humid conditions), then high glass transition temperature PPAs provide an interesting alternative.

In the chart below, we provide an indicative calculation of part performance, weight, and processing optimization potential in relation to part price. The higher the Specific Strength/Price Index, the better.

PPA GF50% (PA4T GF50, ForTii® Ace MX53T) is a cost-effective way to replace PA66 GF50% or Aluminum A380.

The performance price index includes:

  • Tensile strength at 120°C (which is also representative of 50°C with 95% relative humidity)
  • Density
  • Weight optimization potential
  • Material price
  • Production cost efficiency (cycle time, secondary operations, etc.)
 
 
 
 
 
 
 
 
 

 

To summarize, the two charts above indicate that PPAs with a high glass transition temperature could replace PA66 GF50% in a sustainable, cost-effective way, so long as the PPA is not based on PA66.

ForTii® Ace MX53T (PA4T GF50) provides a sustainable and cost-effective alternative to PA66 GF50 within the current market and pricing regime, where PA66 is in short supply. This holds for designs that are optimized for maximum weight reduction, resulting in thinner walls, and therefore potentially faster cycle times. ForTii Ace MX53T is likely not a direct drop-in solution for existing tooling, however it is the most robust candidate material for new projects. The material enables the design and production of future-proof parts due the material’s lower and slower moisture absorption, high dimensional stability, low creep at elevated temperatures, and excellence resistance to chemicals, including road salt, coolants, acids, and engine and transmission oils. All sales of ForTii Ace MX53T are backed by full support from our team of experts, including an extensive data package, material cards, part prototyping, design and molding support.

Read more for other solutions next to ForTii. 

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