By Lisa Tocci
LAS VEGAS – ExxonMobil Chemical on Monday said it has launched production of a new generation of high-viscosity polyalphaolefin, created with a proprietary metallocene catalyst process. With a planned initial production of 15,000 tons per year, it boasts that the beefy synthetic base stock will lift PAO in terms of both availability and performance.
The new base stock, called mPAO to distinguish its metallocene roots from conventional PAOs, is being manufactured under contract at Albemarle Chemical and will be marketed under the brand name SpectraSyn Elite, Habib Quazi, vice president synthetics, told Lube Report in an interview Monday. The product was unveiled here at the annual meeting of the Society of Tribologists and Lubrication Engineers.
Usually, PAO molecules have a prominent backbone, from which short and long side-chains radiate in a random way. The metallocene version, by contrast, has a comb-like structure and the short, bristling side-chains are absent. This shape offers improved rheological properties and flow characteristics, which translate into better shear stability, lower pour point and higher viscosity index than conventional PAO.
The viscosity index of the heavyweight 150 centiStoke mPAO tops 200, while less-viscous 100 cSt conventional PAO usually hits about 170. In a formulated oil, this spells potential for efficiency gains, the company said.
A number of companies around the world make low-vis PAO, but only two – ExxonMobil Chemical and Chemtura – make high-vis PAO, which has kept supply tight for a number of years. The new capacity at Albemarle was announced last year, but the fact that it would use a metallocene process was kept under tight wraps until now.
ExxonMobil Chemical's Carolyn Moore, global marketing manager, synthetics, explained that a metallocene form of a catalyst is a single-site catalyst, with a unique geometric structure that results in a very uniform chemical product, with an absence of side-chains and much higher shear stability.
"It's a simpler process," she remarked, "and it allows us to skip some steps" while still tailoring molecules to have specific properties. While the process can be used to make different viscosities of PAO, the initial product is a 150 centiStoke grade that she says gives flexibility to meet a wide range of viscosity targets in finished products. Other viscosities are possible, but before expanding to add other weights, "we will work with our customers to see if a broader portfolio will offer value to them."
"Synthetic lubricants are seeing a lot of rapid growth, and we see them as displacing conventional lubricants in more applications," Quazi said. While he declined to say what the likely cost of SpectraSyn Elite would be, in comparison with conventional PAO of an equivalent weight, he stressed that the value of the new base stock needs to be appreciated.
"We see this as a value proposition for our customers," he said. "This molecule lets the lubricant marketer create a product with higher performance, so it has to have a value that makes sense."
The company is taking a calculated approach in introducing the product to formulators, in hopes of placing SpectraSyn Elite in premium applications. Initial discussions with lubricant manufacturers, and legal agreements to protect the proprietary chemistry, will be put in place before samples go out, for example. After those steps, Quazi said, drum-size samples should begin going to customers in the third quarter.
Quazi said the target for mPAO is high-severity applications, including driveline and gear oils, compressor lubricants, transmission fluids, and industrial lubricants. An important part of the marketing plan is to stress the 150 cSt product's low-temperature performance. The 150 cSt base stock has a very low pour point of -33 degrees C, which is even better than a lighter-weight conventional 100 cSt PAO (which hits -30 C).
Although it is an API Group IV oil, Moore does not expect formulators will simply drop it in as a replacement for regular PAO. "We think they will want to reformulate in order to take advantage of its enhanced properties," she commented.
Although it has PAO production in Beaumont, Texas, and Gravenchon, France, the company decided to manufacture mPAO at Albemarle "because we saw some synergies with bringing production up quickly there," Quazi noted. The long lead time from research to pilot plant to production -- five years -- shows its commitment to the synthetic lubes market, he added.