"The tightness in the PA12 polymer supply actually started more than two years ago, caused by increased demand in photovoltaic solar and oil and gas applications, and customers began asking for replacements," said Lee.
"The largest and most critical area of replacement needed now is in fuel lines and truck air brake lines. In these, you're always trying to balance the flexibility of the material with chemical and salt resistance, and the material's processability. The properties needed can vary by processor, or application, or OEM. The trick is to balance the right potential substitute with those properties."
Other polyamide grades of PA 6/10 plastics such as Rhodia's castor bean oil-based Technyl eXten can replace nylon 12 in injection-molding parts like quick connectors for fuel lines. (Source: Rhodia)
The difficulty and the challenge are that PA 12 may have been used in applications where it didn't need to be, and where alternatives exist, said Lee. Every application needs to be reviewed on its own to see what's possible. The vast majority of PA 12 replacements will likely be based on other polyamide chemistries.
Other producers of castor-based polyamides include Radici Plastics and Rhodia. Rhodia is conducting trials of its Technyl eXten PA6.10 product for use in automotive and industrial tubing and flexible hoses, as well as fuel quick connectors, said Alan Dubin, business development and technical service manager, North America, for Rhodia Engineering Plastics, in an interview.
Technyl eXten 6/10 grades are available for both extrusion and injection molding, Dubin said. They are especially suited to fittings and adapters for engine fuel systems and flexible tubes for power-assisted control systems. In chemical resistance and mechanical properties for some components, such as quick connectors and other injection-molded parts, as well as in some extrusion-molded applications, these grades may actually perform better than PA 12.
"We've done three automotive customer studies for major manufacturers of fuel line quick connectors that show virtually no change in part dimensions or part performance," said Dubin. "They have evaluated our material in several different injection-molded products."
PA 6/10 has virtually the same range of operating temperatures as PA 12, with similar results in heat aging characteristics. Making the switch from PA 12 to 6/10 should also result in a substantial cost reduction. Dubin says evaluations of extrusion-molded product performance are ongoing.
Interesting to see how supply chains hold up to stress, no doubt about it. As they say, if you're going to put all of your eggs in one basket - then watch that basket! It begs the question as to whether the problem is a supply chain without any breadth of suppliers, or a supply chain in which the suppliers have too much risk. I haven't heard anything about the results of the investigation into the fire in the first place, which might be where the tru problem lies.
TJ, thanks for that comment. I was surprised to learn what a big market share Evonik had, and therefore what a big effect it could have when its plant went offline. I suspect the picture will look pretty different in the next few months.
Thanks, Dave. Like I said, I've seen no mention of EPA requirements. Those could be part of the 5,000 hours of testing, or it might be something already done separately by the materials producers to meet their own automotive standards, since I doubt EPA approval could be achieved in the 3-4 week compressed schedules.
@Ann: Yes, I'm refering to multilayer tubing used for fuel lines. The EPA has regulations regarding evaporative emissions for both automotive and non-automotive applications. Hydrocarbons can permeate through plastic tubing and escape into the atmosphere. It's important to limit this. (This is what our barrier layer does).
I'm not sure what the automotive requirement is, but the marine requirement is 15 grams per square meter per day maximum. This is measured according to one of two SAE standards, depending on whether it is plastic or rubber hose. However, since I'm not directly involved in regulatory compliance, I'm not sure exactly how this needs to be documented to EPA, or what the approval process is.
Dave, EPA requirements were not discussed regarding replacement materials. That said, can you tell us more about the context for the barrier layer you mention? Are you referring to the multi-layer tubing mentioned in the article?
@Ann: Any word on how EPA is handling this with regard to permeation requirements? In our application, there is a barrier layer which is made out of PVDF, not nylon-12, and this barrier layer is not changing. In our design, we rely mainly on this barrier layer (not the nylon-12 itself) to prevent permeation, so we don't expect any problems with EPA approval. But what about in cases where there is no barrier layer?
Tim, thanks for your input. As I reported, DuPont, among others, said that customers began asking for alternatives about two years ago when supply began tightening due to increased demand from solar panel makers and the oil & gas industry. Suppliers may well have begun those efforts even earlier internally. However, the main crunch here is caused by the material's use in automotive manufacturing, where changes in materials do not occur or easily. 5,000 hours, or about 7 months, is the usual required time for testing a new material for fuel lines, the main class of parts affected. This has somehow been fast-tracked down to 3 or 4 weeks by the AIAG's action.
Production of nylon 12 monomer feed stock is extremely difficult and expensive to complete on a large scale. The alternative plans of Dupont and others were most likely completed years ago as an attempt to take market share from Evonik, but they were not cost feasible. Now with end users scrambling to get some sort of alternative material, they are willing to pay a premium for the alternative material and the testing required to qualify it for use.
Naperlou, the problem has cropped up repeatedly in the last 10 years. Two manufacturers in Japan represented a 25% loss of global silicon wafer production after the Earthquake.
The world is WAY too dependent on silicon wafers to tolerate that. The same applies to plastics.
JIT supply chains may be efficient, but only if the supply chain is guaranteed. It is not damage tolerant at all.
Engineers need to take a stronger stand proving this to the accounting department.
Dave, thanks for your input. The 40% figure comes from ICIS, the major industry market analyst, so I tend to believe them: http://www.icis.com/Articles/2012/04/30/9554265/news-focus-producers-scramble-to-provide-polyamide-12-alternatives-for-auto.html I agree that it will be very interesting to see if using replacements--and specifically bio-plastic replacements--will continue after the supply of nylon 12 comes back up. There are many other possible replacement products, including Arkema's, but the purpose of the article was not to give a detailed list of alternatives: that's been well covered already in the plastics vertical media and by ICIS.
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