For all of this attention, though, prospects in the automotive segment are stirring little enthusiasm for the additive companies that serve it. Despite tightness of supply in the market, several have stated this year that the industry is unlikely to make significant near-term investments in additional capacity because of poor financial returns. Meanwhile, demand for additives for industrial lubes is growing at a faster, though still modest rate.

A 2002 study by Freedonia Group predicted the automotive segment of the U.S. lubes market would demand 1.4 billion pounds of additives this year, compared to 530 million pounds for the industrial segment. The Cleveland-based market research firm has not updated the study, Lubricant Additives, but industry sources agreed that its projections are reasonably accurate.

Consumption of industrial additives has been rising at a bit less than 2.5 percent the past five years, observers said. That rate may be uninspiring, but it is twice the pace of growth in the automotive segment.

In a February presentation to the ICIS World Base Oils Conference in London, Dan Sheets, vice president of sales for Lubrizols Lubricant Additive segment, said the automotive segment is dragging because of trends toward increased drain intervals and smaller engine sumps. Sheets said he sees little likelihood of significant investments to increase additive manufacturing capacity – comments echoed at the same conference by Infineum Industry Liason Manager Brian Crichton and the following month by Afton President C.S. Warren Huang at a Hong Kong conference sponsored by Fuels & Lubes Asia.

A Look under the Hood

Motor oils are the biggest application for lubricant additives, accounting for most of the volume used in automotive applications. Passenger car oils meeting North Americas newest industry specification – ILSAC GF-4 – are about 20 percent additives and 80 percent base oil. Because of how they are packaged, formulators divide such additives into two parts: viscosity index improver packages, which also include pour-point depressants; and detergent inhibitor packages, which include detergents, antiwear agents, corrosion inhibitors, antioxidants, defoamers and friction modifiers.

Viscosity index packages account for approximately 30 percent of PCMO additive volume. Formulators use polymers such as polymethacrylates and styrene-isoprene to improve the oils ability to maintain viscosity across a range of temperatures and to keep it from thickening too much as temperatures decrease. Demands on these parameters have risen in recent years, but improvements have come mostly from increased use of more highly refined base oils, which have higher viscosity indices and lower pour points. There has been little change in the additive chemistries used for these properties.

Detergent inhibitor packages constitute approximately 70 percent of additive volume in GF-4 formulas. Some two-thirds of that volume is dispersants – typically succinimides used to inhibit deposits from forming on the engine. Another quarter is detergents, typically salicylates, sulfonates or phenates that clean out impurities. Antiwear agents are the next-biggest category, making up somewhat less than a tenth of detergent packages.

Heavy Metal and Heavy Duty

Significant changes are afoot in the use of antiwear agents and other supplementary categories – corrosion inhibitors, antioxidants and friction modifiers – largely because of efforts to protect pollution control equipment. Increasingly stringent air emissions mandates have required carmakers to ensure that these systems continue to function throughout a vehicles lifetime. Carmakers, in turn, have demanded engine oils with lower levels of sulfur, phosphorous and metal compounds – materials that they blame for poisoning exhaust catalysts.

Oil and additive companies dispute those claims but have been forced to find substitutes for components such as zinc dialkyl dithiophosphates (ZDDPs) – long employed as cost-effective providers of antiwear protection as well as corrosion inhibition. They contain sulfur, phosphorous and metal. GF-4 also ratcheted up the requirement for antioxidants, but some of the traditional choices contain sulfur. This again raised the catalyst-compatibility issue and forced GF-4 formulators to shift toward more expensive options, such as aminic and phenolic antioxidants.

Because of environmental concerns, things have been changing dramatically for detergent packages, said Angelo Posa, manager of market analysis for Lubrizol Lubricant Additives, who is based in Wickliffe, Ohio. There have been significant changes in the chemicals that are used, and we expect that will continue.

Engine oils for heavy-duty trucks have similar makeups but are being stretched by their own environmental issues – most notably new caps on soot emissions. In the United States, these led to this years adoption of a new heavy-duty engine oil specification, CJ-4, designed to cope with significantly higher levels of crankcase soot. Consequently, formulators say deposit and soot control now account for approximately three-quarters of the additive volume for these oils.

ATF and Gear Oils

After engine oils, automatic transmission fluids comprise the next-biggest category in the automotive lubricant segment. Here, too, industry has raised performance demands in recent years – pushing fluids to last longer at higher temperatures and pressure. But these demands have been met primarily through the use of more highly refined base stocks.

Additives constitute between 10 percent and 20 percent by volume of ATFs. Viscosity index improvers claim between one-half and three-quarters of that volume, while dispersants can be approximately one-fourth. Most fluids contain chemicals designed to keep seals from shrinking, too, although the amount varies considerably – from zero to 20 percent of the package. Antioxidants, antiwear agents, defoamers and corrosion inhibitors together comprise up to 15 percent.

Gear oils are also being pushed to accommodate higher temperatures and pressures. Again, base oil choices have partly met the demands, but additive concentrations have increased moderately. The proportion of additives in these oils ranges between 5 percent and 10 percent. Extreme pressure antiwear agents may account for 40 percent to 50 percent of that volume, while other antiwear materials account for approximately 20 percent more. Dispersants account for 10 percent, followed by corrosion inhibitors, fluidity modifiers and friction modifiers at approximately 5 percent each.

The higher grades of base oils have better oxidation stability, and their use would actually reduce the requirement for antioxidant additives, if nothing else were to change, explained Aftons Tony Rollin, technical director of driveline and industrial research in Richmond, Va. But power densities in automatic transmissions and gear boxes are increasing. So tests such as GMs ATF oxidation test have increased from 300 hours to 450 hours, without a change in passing limits. Greater test severity can offset the use of better base oils, so additive treats can be higher.

Industrial Pressures

Additives for industrial lubricants are more difficult to profile because the segment is much more fragmented than are automotive lubricants. Industrial engine oils are the largest category, followed by hydraulic fluids and metalworking fluids.

In general, antiwear protection from extreme pressure is a higher priority for the industrial segment, accounting for as much as 50 percent of additive volume, according to Heather Reinholt, global product manager for specialties at Infineum. Antioxidants account for up to 25 percent and corrosion inhibitors another 15 percent.

Detergent and dispersant additives, which form the foundation of crankcase formulations, have limited application in the majority of industrial lubricant products, said Rheinholt, who is based in Linden, N.J. Viscosity modifiers are not as widely used in industrial lubricants as in crankcase applications. Pour-point depressants are, however, important components of most liquid industrial lubricants.

The additive proportion of many industrial lubes is significantly lower than in the automotive segment. Industrial engine and gear oils are notable exceptions. The former require higher treat levels because they face higher pressures, heavy soot deposits, and higher levels of acid than do engine oils used in passenger cars or on-high-way heavy-duty trucks.

Industrial gear oils require the same level of corrosion inhibitors as their automotive counterparts.

Some applications require antioxidants, although sulfur can accomplish some of that, said Ian Macpherson, marketing director for commercial and industrial solutions at Afton. Half of the industry wants dispersancy, sometimes quite high levels. Also, its important to recognize that a lot of the industry will use automotive gear additives in industrial applications.

Hydraulics and More

Additives account for as little as one percent of the volume in hydraulic oils, with one-third to one-half of that being zinc dithiophosphate (ZDDP) used for antiwear. These fluids also contain corrosion inhibitors and trace amounts of demulsification agents. Some also contain phenolic or aminic antioxidants at levels similar to the ZDDP. In Europe it is common to find ashless (metals-free) hydraulic fluids that nix ZDDP, and which use twice as much antioxidant.

Typical turbine and circulating oils are approximately 99 percent base oil. The only additives they contain are antioxidants and rust inhibitors. (Hence they are commonly referred to as R&O oils, to show they simply keep rust and oxidation under control.)

Many industrial lubricants are also undergoing a shift from Group I base oils to more highly refined stocks, though generally not to the extent of the automotive segment. While bringing some benefits, the more highly refined oils have the drawback of imparting less solvency.

Some [additive] components, even though they are used at very low levels, can have a very challenging time staying in solution, the Richmond, Va., based Macpherson said. As a result, you have to modify the chemistry or add things like co-solvents. And some of these materials – esters, for example – are expensive.