Automotive Greases

Polymer Additives Ease Bright Stock Woes for Lubricating Greases


Polymer Additives Ease Bright Stock Woes for Lubricating Greases
© willymona

Bright stock, a high-viscosity Group I base oil, has been prevalent in the lubricant industry for decades in industrial applications. When production has been plentiful, bright stock has been used as the base oil for everything from industrial gear oils to greases. Essentially, it is a breadbasket component that encompasses multiple end uses and has the following benefits for grease manufacturers:

  • Thickening properties that enable formulation in higher-viscosity ranges 
  • Compatibility with other oils, additive packages and viscosity modifiers
  • Historically proven performance, which allows blenders and end users to be more comfortable with its use in finished lubricants
  • Ability to be used as a high percentage of the finished lubricant formulation

Although these advantages are important, developments in recent decades have revealed that bright stock also brings with it some potential pitfalls.

Group I base oil production began to decline in the early 2000s with the introduction of Group II and Group III base stocks. Adoption of the new base oils took off particularly quickly in North America and Europe, followed later by Asia. The emphasis on Group II and Group III base stocks grew as the original equipment manufacturers started to produce more efficient vehicles and equipment that demanded better-quality, lower-sulfur base stocks with thinner viscosities.

In fact, the tightening market that we see today is at least partly marked by the many supply disruptions that reared their heads in 2021, when prices skyrocketed and affected the economics of using bright stock in greases. Group I availability is continually shrinking, putting manufacturer product lines that depend on the associated bright stock at risk.

With the trend of lower supplies and steady demand showing no signs of changing in the foreseeable future, the time to discuss potential replacements for bright stock is now—before the decreasing supply and cost pressures put a strain on lubricant manufacturers’ product-line continuity and profitability. 

Fortunately, a few viable alternatives to bright stock can be used to formulate greases. For instance, polymer alternatives to bright stock can provide comparable performance at a lower cost.

Why Is Bright Stock Less Attractive to Grease Formulators?

Declining Group I oil production in favor of Group II and Group III base stocks in recent years has caused a constriction of the supply chain and forced lubricant manufacturers to reassess how much bright stock should be used in their grease formulations. Unusual supply chain disruptions in the form of unstable weather and a global pandemic have hastened the decline in production, which has raised prices significantly.

Additional factors have affected the production of bright stock and created problems for which there are no easy answers. Many Group I plants are aging and energy intensive. To keep them producing at previous levels would require significant infrastructure enhancements for efficient operation. Companies are seeing few advantages to making those investments and, in many cases, are opting to close plants instead, further restricting supply.

Investment in base oil production is focused on higher-quality oils, leading companies to invest in mega-scale facilities with the capability of processing a broader slate of crude oils and raw materials. The trend is expected to continue for these base oils.

Quality issues have also begun to affect the production of bright stock as fewer facilities produce it. Lower-quality, inconsistent bright stock fails to meet today’s technical grease demands and can lead to:

  • Poor performance
  • Product consistency issues
  • Falling confidence in the ability of lubricant manufacturers to deliver on their promised quality standards

The Group I downtrend is expected to continue as increasing regulatory and end-use demands for reduced emissions and better fuel efficiency force manufacturers to redesign their grease portfolios. As a result, lubricant producers are finding it necessary to seek alternatives to bright stock in their grease formulations to keep up with today’s demands and keep prices down for end users.

Other Alternatives to Bright Stock

Importantly, not all options to replace traditional bright stock are equally viable. Consideration of some different approaches to assess alternatives is crucial.

While some manufacturers hope to find alternate sources for conventional bright stock, they’re often finding the task futile and arduous given the market. Simply put, there is not enough bright stock to go around, and the supply continues to be constricted as more Group I plants close. 

In addition, a significant investment of time and money is required to qualify new vendors and to negotiate new supply chains. At best, this is a short-term tactical approach that puts companies in the uncomfortable position of having to adjust their operations every time a change to a conventional supplier needs to be made. It generates increased production costs and complexity to the process, which makes it uneconomical to produce bright stock.

While some manufacturers hope to find alternate sources for conventional bright stock, they’re often finding the task futile and arduous given the market.

Grease manufacturers need to determine how to drive costs down so customers can still buy their products. The answer may lie in engineered polymers, like polybutenes or olefin copolymers, often referred to as OCP.

The Potential Solution

In grease applications, many lubricant manufacturers are looking to use PIB or OCP to replace bright stock as the base for lubricants. Unlike other alternatives, supply of these engineered substitutes is readily available.

Performance polymers also provide several advantages over traditional bright stock. They provide more consistent quality and perform just as well as traditional bright stock, allowing global manufacturers to standardize formulations. This is vital given that the supply of and demand for conventional Group I base oils will vary by region. As an engineered product, these polymers do not contain the impurities and less-than-desirable molecular structure of natural materials, making blending and final product outcomes more stable. 

Performance polymers are engineered with a narrow range of molecular weights and offer better thickening efficiency than greases produced with bright stock, which supports the potential for lower treat rates. This reduction can lead to significant cost savings, which is a win-win opportunity for product quality and the bottom line.

What makes OCPs revolutionary, however, is that manufacturers can achieve the same performance while also saving costs. By reducing the amount of bright stock used in greases with the use of OCP, manufacturers can save up to 22% on base oil costs (though it’s important to note that the amount of savings depends on the initial cost of the base oil used). 

Performance polymers are engineered with a narrow range of molecular weights and offer better thickening efficiency than greases produced with bright stock.

Finally, there are potential benefits and advantages to using polymers as a more sustainable solution due to lubricant consumption reduction. Although studies are still under way, the initial research indicates that performance polymers are better for the environment than traditional bright stock-based greases. These performance polymers are more water resistant than traditional greases and therefore are less likely to be dispersed into the environment unnecessarily. This will enable grease manufacturers to improve their environmental friendliness as the world moves toward addressing those concerns.

What It Means to You

As the production and quality of traditional Group I bright stock continue to decline, it will be incumbent on grease manufacturers to find viable alternatives. The balance between the manufacturers’ needs and the costs to the end user is not unachievable. But it could take a re-examination of how greases are currently formulated to find an alternative that will not compromise performance and will not raise costs.

Polymer alternatives appear to be the most logical successor to traditional bright stock-based greases as conventional Group I bright stock supplies continue to plummet. They are readily available, versatile in their application and they offer comparable performance and the potential for huge cost savings based on the more consistent quality.

For the grease manufacturers, using engineered polymers instead of traditional bright stock will help simplify the logistics and inventory management because one polymer can be used for multiple grease applications. User-friendly packaging improves operational efficiency, and production consistency allows for robust and reliable formulations, improving the image of the formulator in the competitive market.

Finally, a significant reduction in bright stock use allows manufacturers to lower prices for the end user. This means formulators who take advantage of the latest technology can become more competitive in the space and gain market share.

In short, while bright stock may not be completely replaced in the near future, it is crucial for grease manufacturers to start thinking about what alternatives will be available and what will make the most sense to use in the future. Polymer alternatives may be the answer to both of those questions.  

Benny Cao is the global commercial manager – grease for the Lubrizol Corporation, based in Wickliffe, Ohio.

Carlos Nazario is the North America product manager – grease additives for the Lubrizol Corporation.