Many people, even in the lubricants industry, immediately associate the word lubricants with vehicle engines and axles, metalworking shops, hydraulic equipment, rolling mills or some other type of hard-working automotive or industrial use. With their focus on producing and selling in bulk, they often dont consider all of the niche applications that require highly specific oils and greases in precise volumes, such as kitchen faucets, shower heads, electronic windows in vehicles, air-conditioning units, high-performance drive chains, textile drying ovens and chipboard presses.
Applications like these are easily overlooked by oil companies seeking the low-hanging fruit – but theyre ripe for picking by formulators who know how to develop and deliver a highly customized product, according to Thomas Brexeler, director of special lubricants at Hagen, Germany-based Carl Bechem GmbH. At a recent industry conference, he offered delegates some insights into a world of small but technically demanding products.
Fit to Drink
Take the fitting industry, for example. Many aspects of a plumbing system must be well oiled, from vacuum breakers and valves to sprayers and handles. Formulating lubricants for these applications comes with a specific set of requirements and challenges, Brexeler told the Uniti Mineral Oil Technology Congress in Stuttgart, Germany, in April.
The lubricant for a faucet handle, he explained, needs to reduce friction and torque during switching operation for a users operating comfort over a decade or more of service. Add in cultural and geographic differences, and requirements can be even more specific: In Asia, for example, many end users want to be able to easily lift the handle with their pinkie finger alone.
The product must also allow for low abrasion on frictional metal contact surfaces and prevent stick-slip in valve taps at high torques – a performance property measured in load tests that can run for as many as 500,000 operating cycles. There are also low-torque contacts that must be protected, such as ceramic discs, and of course the product must be highly resistant to washing out from contact with water.
Comparatively, [fitting industry lubricants] are highly viscous, Brexeler said. The consistency should be like paste to prevent leaks. Youre really quite limited in respect to what oil you can use. Bechem formulates such greases or pastes with silicone base oil having a viscosity range of 3,100 mm2/s at 40 degrees Celsius and 1,200 mm2/s at 100 C, per Germanys DIN 51562 test. Once thickened, typically with polytetrafluoroethylene, the mixture is tested against industry standards for worked penetration, oil separation – almost zero oil bleed is tolerated – and water resistance.
While the friction properties of fitting industry oils are paramount, theres much more under the surface when it comes to formulation requirements, as the real work comes with satisfying water safety and regulatory protocols, said Brexeler, who spoke in German with simultaneous translation.
The challenge in formulating is not just in its tribology aspects. If it were, many companies would be able to make these oils, he observed. It also must be harmless and there are different directives regulating safety measures in almost every country. You have to leave out some ingredients which are banned from the start.
For drinking water approvals, tests must determine that after contact with all the different types of metallic materials in the system – and with the lubricant – the water still has appropriate smell and taste; color and turbidity; cyto-toxicity; metal levels; and limited growth of microorganisms.
Another hurdle for suppliers is that drinking water approval programs are individualized in various countries and often regulated by national boards. In Germany, where Carl Bechem was founded in 1834, formulators must follow the guideline from the nations environmental authority, Umweltbundesamt. The Attestation de Conformite Sanitaire oversees the approval process in France. In the United Kingdom, water is governed by the Water Regulations Advisory Scheme. And products in the United States must comply with NSF Internationals Standard 61.
Lubricants for drinking water applications must not only pass the various tests and sanitation requirements of countries into which they are being marketed, but they also must be tested with cold, warm and hot water and be able to withstand all temperatures, said Brexeler. And of course, the consumer experience must be assured. The American Water Works Association says that tastes and odors are the leading cause of consumer complaints to water utilities – so lubricants must not contribute to that.
How much lubricant does the fitting industry buy each year? Brexeler didnt say, but a hint can be found in a 2015 study commissioned by the Plumbing Manufacturers International. The Illinois-based trade group found U.S. homes are fitted with 410.3 million lavatory faucets and 245 million shower heads, plus millions more are installed in commercial buildings. Each of these may get only a few dabs of lubricant at the factory. But since PMIs study also found the typical shower head or faucet gets replaced every 12 to 15 years, the OEMs thirst is unquenchable.
Hear that Noise?
Another challenging and esoteric need, said Brexeler, is oil for bearings that require very low noise and vibration levels.
For example, he said, for any internal part of a DVD player that is lubricated, noise must be nonexistent. Other examples include electric motor bearings, cooling fans and other household appliances; air-conditioner electric motor bearings; automotive ball bearings and hard disk drive bearings.
Greases are crucial to the vibration and noise characteristics of the bearings, he pointed out. Low-noise bearings have to be lubricated with low-noise greases to reach a specific low-noise level. The oils must also be extremely high performance in terms of speed, load and temperature range, both at start-up and over the entire life span of the device. Only the highest purity level in regards to ingredients and production will do. These products must exhibit good shear stability, dust-protection qualities and good heat resistance, as well.
To find out just how low-noise a grease is, formulators must perform qualitative analytics and specific tests. Vibration analysis instruments – and in some cases, microscopes – measure noise-producing particles in the grease. While particles up to 40 microns in size (the thickness of a fine human hair) may be acceptable in most applications, particles in a low-noise grease must be less than 5 microns so nothing is audible as the bearings spin.
This will require the grease plant to use precise, clean and reproducible processes, Brexeler explained, batch after batch. At the front end, raw materials are filtered to guarantee their purity, and at the other end, where other industrial greases may be milled to smooth out lumpy fibers, a low-noise grease may be painstakingly fed through the rollers of a narrow-tolerance homogenizer. The result of all this care is a grease that literally can fill a tiny niche at a premium price.
Chain Reaction
Chain oils represent a third set of challenges for specialty lubricant formulators. High-performance chain lubricants must have good viscosity index characteristics and are often blended with synthetic esters. They must be able to handle a temperature range from below -40 degrees C up to 250 C and maintain minimal evaporation even at high temperatures. They also should provide good tackiness and creeping properties, as no grease should be flung out when the chain moves. Depending on their specific application, they also may need to be food-grade, or demonstrate compatibility with certain paints and plastics.
Examples of high-performance chain oils – which are often applied by automatic lubricators – are found in continuous chipboard presses, conveyor chains in paint shops, drying ovens, plastic films for foil production, textile stenters, insulation mat production equipment, glass container machines, packing cartons and more.
On textile stenter clips and chains, for example, the oil must penetrate some of the smallest components of a very large machine, but often cant reasonably be changed during the units lifespan. On a chipboard press, the oil must be resistant to high temperatures but provide high protection against wear.
Niche applications obviously do not represent high-volume businesses for lubricant formulators, Brexeler concluded, but they can be highly lucrative. Sometimes, small is beautiful.