FEATURE (Continued from Page 8)


PAGs meanwhile provide a complementary set of benefits:


High lubricity and viscosity index


Low volatility and high thermal/oxidation stability


Can be optimised to give a range of solubility behaviours, e.g. low miscibil ity important for hydrofluorocarbon and NH3 compressors, or low solubility with hydrocarbons etc. to prevent dilution. Inverse solubility can provide interesting properties in metal working fluids and quenchants.


Good oxidative stability and heat transfe r properties, coupled with clean burning to extend oil life


Some grades are biodegradable, allowing them to meet environmental standards.


Knowledge of synthetics have reached a level where tailoring of 'designer' lubricants becomes possible, provided operating cond itions are understood. Basefluid developers (as opposed to pure manufacturers) are able to call on t his expertise to help formulators to devel op and market fi nished packages.


CASE STUDIES


CASE STUDY- AUTOMOTIVE The automotive synthetic lubricant market is largely driven by performance, indicated by bodies like SAE, ACEA and ILSAC. Synthetics allow oils to meet easily the existing and new specifications set by these bodies, as well as the new OEM requirements for extreme long oil drain periods. This translates into increased thermal stability, particularly given by Esters, superior in comparison with other basestocks. As new designs and costs dictate smaller, more powerful engines, reduced cooling air for aerodynamic efficiency, and new direct fuel injection systems, these result in hot run engine conditions.


Existing and new specifications focus on high levels of fuel economy (Leave out CAFE). Technically this translates to lower viscosity oils on a SW/OW types, meeting the more severe volatility limits and still to provide optimal engine protection. Esters contribute to these aspects on a high level, reasons for the increasing popularity of these fluids.


Large regional differences still exist in the use of synthetics, with Europe, and particularly Germany, leading the way. Faster motorway speed limits (none in Germany!) with smaller cars, coupled with locally severe ' OEM requirements producing the need. The US with slower speed limits, huge engines and cheaper fuel has traditionally turned oil changing outlets such as Jiffy Lube, with 3000 miles being a typical changeout period. There are clear signs of further grow for synthetics in Europe and change in Asia and US, where the use of synthetics is winning in popularity, all in view of the new specifications to come.


CASE STUDY- REFRIGERATION LUBRICANTS


Refrigeration lubricants provide an excellent example of how environmental legislation can lead to a step change in lubricant formulation and market requirements.


Traditionally refrigeration systems (domestic, industrial, commercial and transport applications) almost all relied on chlorofluorocarbons (CFCs) with


mineral oil lubricants. Amid concerns over the effect of these refrigerants on the ozone layer, the Montreal Protocol banned most CFC use by the end of 1994, to be followed by a phase-out of the usage of HCFC. While replacement refrigerant gases were quickly developed (notable HFC 134a) existing lubricants were incompatible. For instance, they were immiscible together, leading to capillary blockages and system failures.


Large development programs investigated a number of alternative lubricants, eventually settling on polyol esters for most uses, and PAGs for first-fill automotive air-conditioning. These products show the miscibility, lubricity and stability required for long term use in hermetic, sealed-for-life, pumping systems, where they are required to perform for up to 20 years, as well as larger industrial and commercial refrigeration and air-conditioning system that require servicing.


CFC phase out led to huge growth in the domestic and automotive refrigeration sectors in period 92-95. A further step change will accompany the later phase- out dates. Now that the major transition is achieved, work is underway t o optimise the operation of lubricant s, particularly around energy efficiency. Recent legislation in the USA requires all domestic appliances achieve 30% improvement in energy efficiency . In Asia , system manufa cturers have announced self imposed energy saving targets . The European market requires energy consumption labels to be shown to consumers, and demands are being made to improve overall performance.


The flexibility of the polyol ester family of lubricants, has enabled highly optimised polyol esters (HOPOEs) to be tailored to meet specific performance requirements. It has been demonstrated that the compressor lubricant has a significant impact on the overall energy efficiency of the system. Indeed, a new optimised product range of ultra-low high lubricity products (e.g. the Uniqema HPius range) has been developed to help the industry meet these challenges.


CASE STUDY- METAL WORKING FLUIDS


Developments in this area are dominated by safety and environmental factors and also largely influenced by the trend to extend the lifetime of the metal working fluids.


In the related area of quenching fluids, PAG solutions are taking over from the traditional oils. While PAGs are more expensive and do not perform quite as well in quenching, they are generally diluted to 10% with water, reducing costs and logistics. The reduced risks of fire, disposal costs, and environmental measures all contribute to lower cost in use. Without vats of boiling oil, the healthiness of the workplace is vastly improved.


Ester based metal working formulations are offering longer lifetime thus reducing overall disposal costs and can also present low ecotoxicity impact. The move towards total fluid management for many customers allows these savings to be quantified and valued by final customers. New developments in Self-Emulsifying Esters extending lifetime of the metal working fluids are also an important step in looking at saving overall costs of a metal working operation through the use of synthetic base fluids.


MARKET SHIFTS


The lubricants industry is in a state of flux, driven principally by the following factors:


(Continued on Page II) ISSUE 37 • MAY 1999


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