Share this article:     

Lubricant and metalworking fluid formulators are entering a period in which additive choice is no longer driven by performance alone. The modern formulation brief increasingly asks one chemistry—or one additive package—to support wear control, corrosion protection, oxidation stability, foam control, microbial robustness, mist reduction, label management, and environmental positioning at the same time. This is especially visible in metalworking fluids, where formulators must balance lubricity, cooling, corrosion protection, chip removal, foam, hard-water stability, and microbial contamination in severe operating environments.

The shift is not simply a “green chemistry” story. It is a convergence of chemical management, hazard communication, worker exposure, biocide authorization, PFAS reporting and restriction, VOC control, and environmental-label expectations. For experienced formulators, the practical question is not whether multifunctional additives are attractive; it is how to evaluate them rigorously enough that a simplified additive slate does not create hidden trade-offs in compatibility, toxicology, field durability, or regulatory status.

What Multifunctional Additives Mean in Modern Formulation 

In formulation practice, a multifunctional additive is best understood as a component or blend that delivers more than one functional contribution at a defined treat rate. UL Prospector’s technical overview describes lubricant additives as chemical components or blends used at specific treat rates to provide one or more functions, and notes that ideal additives are multifunctional and compatible with mineral oil, water, or both, depending on the formulation system. In metalworking fluids, the additive toolbox commonly includes biocides, anti-misting agents, antioxidants, corrosion inhibitors, coupling agents, defoamers, emulsifiers, extreme-pressure agents, lubricity additives, metal deactivators, reserve alkalinity boosters, and wetting agents.

For lubricant formulators, the principal performance targets remain familiar: anti-wear and extreme-pressure protection, friction reduction, oxidation control, corrosion inhibition, seal and elastomer compatibility, deposit control, thermal stability, and longer drain or service intervals. For metalworking fluid formulators, the same performance logic is complicated by water quality, sump biology, foam, mist, tramp oil, metal staining, tool life, and operator exposure. OSHA’s metalworking fluid manual emphasizes that MWFs are complex mixtures of oils, detergents, surfactants, biocides, lubricants, anticorrosive agents, and other ingredients, and that they are used for coolant, lubricant, and corrosion-resistant properties during machining operations.

The growing interest in multifunctionality reflects the need to make each ingredient “earn its place.” STLE’s 2026 review of lubricant additives describes an industry shift toward multifunctional and environmentally friendlier additives and cites examples such as metal-free, low-ash, and hybrid additive approaches that combine rust inhibition, detergency, oxidation stability, anti-wear performance, and friction reduction. In MWFs, STLE’s formulation review states the trend even more directly: formulators are no longer looking for one product for each performance criterion, but for products that meet multiple performance objectives, including labeling requirements.

Regulatory Pressures Reshaping Additive Selection 

PFAS 

PFAS is one of the clearest examples of regulatory pressure that intersects with additive performance. OECD notes that PFAS are used in lubricant components across industrial sectors and can impart wide combinations of properties that enable multiple technical functions at once; the same report also notes that progress in substituting PFAS in lubricants has been limited because of technical and economic challenges. That creates a practical dilemma: chemistries prized for extreme performance, low surface energy, chemical resistance, or harsh-duty lubrication may become harder to justify where disclosure, reporting, restriction, or customer policy pressures increase.

In the United States, EPA’s TSCA Section 8(a)(7) PFAS rule requires manufacturers and importers that have manufactured or imported PFAS or PFAS-containing articles in any year since January 1, 2011, to report information on uses, production volumes, disposal, exposures, and hazards; EPA has also proposed scope modifications and adjusted reporting timing as the rule evolves. In Europe, ECHA published an updated proposal in August 2025 to restrict PFAS under REACH, after authorities from Denmark, Germany, the Netherlands, Norway, and Sweden evaluated more than 5,600 consultation comments; ECHA’s committees continue to evaluate the proposal, and the European Commission will ultimately decide on the restriction.

Hazard Communication 

Hazard communication is becoming more dynamic. OSHA’s 2024 final rule updates the U.S. Hazard Communication Standard to align primarily with GHS Revision 7, improve label and SDS information, address issues from the 2012 standard, and improve alignment with Canada and other federal agencies. Separately, UNECE’s GHS Revision 11 adds or clarifies provisions related to aerosols and chemicals under pressure, skin sensitization using non-animal methods, substances and mixtures hazardous by contributing to global warming, precautionary statements, and simple asphyxiants.

In the EU, the CLP Regulation now includes new hazard classes for endocrine disruption, PBT/vPvB, and PMT/vPvM properties, with transition periods for substances and mixtures already on the market. For formulators, these developments reinforce the need to evaluate additives not only for current SDS classifications but also for emerging hazard endpoints, classification thresholds, and customer acceptance of label language.

Work smarter and win more, with powerful software to manage regulatory, supply chain and sustainability challenges, learn more about ULTRUS here!

Worker Safety and Biocides 

Metalworking fluids present a distinct worker-safety challenge because exposure can occur by inhalation of mist or aerosol and through skin contact with contaminated materials, spray, or fluid-wetted tools and parts. OSHA states that MWF exposure can cause adverse health effects through skin contact and inhalation, and NIOSH recommends limiting MWF aerosol exposure to 0.4 mg/m³ thoracic particulate mass, or 0.5 mg/m³ total particulate mass, as a time-weighted average for up to 10 hours per day during a 40-hour week.

Biocides remain essential for many water-dilutable MWFs, but they are also highly regulated and can contribute to labeling or exposure concerns. ECHA’s Biocidal Products Regulation requires biocidal product authorization before placing products on the EU market and prior approval of the active substances used in those products. EPA defines antimicrobial pesticides as products intended to disinfect, sanitize, reduce, or mitigate microbial growth or protect industrial processes, systems, surfaces, water, or chemical substances from contamination, fouling, or deterioration caused by bacteria, fungi, algae, slime, and other organisms. OSHA’s MWF manual also advises that biocides used in MWFs and sump-side additions should be EPA-registered for that use and used according to registration conditions, with concentrations not exceeding what is needed to meet fluid specifications.

Sustainability and Environmental Requirements 

Environmental requirements are moving from broad claims toward defined criteria. The EU Ecolabel for lubricants is awarded to lubricants meeting strict environmental criteria, including limited aquatic impact, restricted hazardous substances, and performance at least equivalent to conventional lubricants; the current criteria are valid until December 31, 2028. EPA’s Environmentally Acceptable Lubricants document defines EALs around biodegradability, low toxicity, and low bioaccumulation potential, and notes that additive and thickener choices can drive aquatic toxicity even when the base oil is environmentally preferable.

Regional air-quality rules also matter. South Coast AQMD Rule 1144 is designed to reduce VOC emissions from metalworking fluids and direct-contact lubricants used at industrial facilities, and it establishes VOC limits by fluid category, including metal forming, metal removal, metal treating, metal protecting, vanishing oil, and direct-contact lubricant categories. At the policy level, the European Commission’s Chemicals Strategy for Sustainability aims to better protect citizens and the environment, boost safe and sustainable chemicals, phase out PFAS unless uses are essential, and support safe-and-sustainable-by-design chemistry.

Why Regulations Are Increasing Demand for Multifunctional Additives 

Regulation increases demand for multifunctional additives because every added raw material brings another set of questions: inventory status, SDS classification, exposure profile, impurities, regional approvals, customer restrictions, wastewater profile, and sustainability claims. STLE’s MWF review notes that regulatory registration in multiple geographies is often mandatory and that unsatisfactory labeling or the presence of impurities such as formaldehyde, phenol, secondary amines, and boron can be deal breakers. It also notes that GHS, REACH, and TSCA pressures can leave formulators with a shrinking chemical toolbox.

Multifunctional additives can help by reducing formulation complexity, but only when the multifunctionality is real, measurable, and stable in the system. STLE’s 2026 lubricant additive review reports a push to reduce the total number of additives in a product by using base systems or additive chemistries with inherent performance, while also highlighting label-free, low-metal, metal-free, and environmentally recognized additive approaches. The formulation benefit is not simply fewer line items on a bill of materials; it is fewer potential reclassification events, fewer supply-chain dependencies, fewer impurity questions, and a better chance of maintaining performance while reducing restricted or closely watched chemistries.

Current Formulation Trends to Watch 

Bio-based and Lower-Toxicity Formulations 

Bio-based and lower-toxicity approaches are gaining attention, but the technical bar remains high. STLE’s 2025 article on bio-based additive advancements identifies performance, compatibility, cost, and global availability as key requirements, and notes that hydrolytic stability, thermo-oxidative stability, seal swell, solubility, and feedstock stability can be limiting factors. UL Prospector’s 2025 bio-based lubricants article similarly frames the challenge as delivering eco-friendly lubricants that perform under demanding industrial conditions while meeting environmental and compliance benchmarks.

For both lubricant and MWF formulators, the key trend is not a wholesale move to “bio-based” as a single claim. It is selective use of esters, oleochemical derivatives, bio-based surfactant structures, ashless additives, and lower-toxicity packages where they can survive real operating conditions. EPA’s EAL guidance emphasizes that environmentally acceptable lubricants must be assessed for biodegradability, toxicity, and bioaccumulation, while the EU Ecolabel adds criteria for hazardous substance restriction and performance equivalence.

Low-Phosphorus and Label-Conscious Additives 

Label-conscious formulation is becoming a core design discipline. STLE’s MWF formulation review reports that formulators seek to minimize GHS classification and labeling, and it specifically identifies phosphorus additives, boron compounds, biocides, chlorinated paraffins, formaldehyde-condensate biocides, and certain amines as areas of scrutiny in various geographies or customer programs. In lubricant additives, STLE notes movement toward low metal content, metal-free additives, low-ash systems, and low sulfur, phosphorus, and halogen approaches in next-generation technologies such as oil-soluble ionic liquids.

Low-phosphorus does not mean low-performance by default. It means formulators are looking for anti-wear, corrosion, lubricity, emulsification, or surface-active performance with less reliance on chemistries that may complicate labels, discharge profiles, or customer acceptance. The practical implication is more attention to additive synergy, surface competition, treat-rate efficiency, and validation across water hardness, metallurgy, filtration, and coating compatibility.

Electrification and E-Fluids 

Electrification is reshaping lubricant performance requirements. STLE’s review of single electric-vehicle fluids notes that integrated e-modules may require fluids that combine gear and bearing lubrication with thermal management for electric motors and other components, while balancing tribological, rheological, electrical, and thermal properties. UL Prospector’s EV lubrication article similarly describes e-fluids as balancing electrical behavior, thermal management, material compatibility, and wear protection in contact with high-voltage electronics, copper wiring, and specialized polymers.

This trend favors additives and base-fluid systems that can deliver low viscosity for efficiency, oxidation stability for long life, copper and polymer compatibility, controlled conductivity or dielectric behavior, and adequate anti-wear protection under high-speed gear and bearing conditions. It also raises the cost of formulation error: an additive that solves friction but harms copper, elastomers, electrical performance, or thermal aging may fail the broader e-fluid design brief.

Exposure, Mist and Fluid-Life Management 

Exposure and fluid-life management are becoming formulation criteria, not only plant-operating issues. OSHA emphasizes that MWF systems are complex, biologically active, and changing in response to use conditions; its manual recommends written procedures, routine testing, concentration and pH control, microbial monitoring, tramp-oil management, ventilation, and employee training. NIOSH’s recommended exposure limit reinforces the importance of mist control and exposure monitoring for aerosol-generating operations.

For formulators, this makes anti-misting agents, low-foam systems, bio-resistant additives, corrosion inhibitors, and stable emulsifier packages, part of a worker-protection and sustainability strategy. Longer fluid life can reduce waste and downtime, but only if microbial control, corrosion protection, odor, foam, hard-water tolerance, and operator exposure remain acceptable over time.

Forward-Looking Assessment: 2026–2031 

Over the next three to five years, additive selection is likely to become more evidence-intensive and less tolerant of “black box” performance claims. This assessment is based on observed regulatory direction: PFAS reporting and restriction processes are advancing in the U.S. and EU, hazard-classification systems are expanding, biocidal active substances remain authorization-dependent, and ecolabel or EAL frameworks continue to formalize environmental criteria.

The strongest opportunities will be in additive technologies that combine multiple functions with cleaner hazard profiles: corrosion inhibition plus lubricity, bioresistance plus pH stability, anti-wear plus oxidation control, or emulsification plus foam management. STLE’s MWF review already identifies multifunctionality as crucial because formulators must meet multiple performance objectives, including labeling, while its lubricant additive review describes movement toward multifunctional, hybrid systems that combine performance with sustainability and biodegradability.

The main risks are underperformance, regulatory whiplash, and supply fragility. Bio-based or lower-toxicity additives may face hydrolytic stability, thermo-oxidative stability, seal-swell, solubility, cost, and availability issues. PFAS alternatives may be difficult where PFAS previously delivered multiple extreme-performance attributes at once. In water-based MWFs, reducing or changing biocide strategies without adequate system management can create microbial, odor, corrosion, and worker-exposure problems.

Practical Considerations When Evaluating Multifunctional Additives 

1. Define the performance stack before screening ingredients. Specify which functions the additive must deliver—AW/EP, lubricity, corrosion, emulsification, alkalinity, foam control, mist reduction, oxidation stability, biostability, or metal compatibility—and which functions cannot be compromised.

1. Check global regulatory status early. Confirm inventory status, TSCA obligations, REACH/CLP classification, BPR or FIFRA relevance for biocidal claims, and any regional VOC or environmental restrictions before investing in extensive performance testing.

1. Treat SDS and label outcomes as formulation outputs. A technically effective additive may still be unattractive if it triggers hazard statements, customer restrictions, or future reclassification concerns.

1. Validate compatibility in the real formulation matrix. Multifunctional additives should be tested for base-oil or water compatibility, emulsion stability, filtration, foam persistence, hard-water tolerance, seal and elastomer effects, copper and alloy compatibility, paintability, and microbial behavior.

1. Evaluate exposure and use-phase behavior. For MWFs, test misting tendency, aerosol control, skin-contact risks, pH drift, microbial contamination, tramp-oil interaction, and cleaning/recharge behavior, not only bench lubricity or corrosion results.

1. Substantiate environmental claims with endpoints. Biodegradability, aquatic toxicity, bioaccumulation potential, renewable carbon, and ecolabel eligibility should be documented with recognized methods or certification criteria, not inferred from feedstock origin alone.
2. Use ingredient-discovery tools as a starting point, not a substitute for validation. Prospector’s lubricant and metalworking fluid search provides access to technical information such as TDSs, SDSs, specifications, raw materials, formulations, and supplier data; those resources can support initial screening, but final selection still requires supplier documentation, regulatory review, and lab or field validation.

Conclusion 

Multifunctional additives are becoming more important because the formulation environment is becoming more constrained. Lubricant and MWF formulators are being asked to preserve or improve performance while managing PFAS exposure, evolving hazard classifications, biocide authorization, worker exposure, VOC limits, environmental labels, and customer sustainability requirements.

The most successful formulation strategies through 2031 will not simply replace one additive with another. They will redesign additive packages around validated multifunctionality, lower-hazard profiles, global compliance visibility, and application-specific durability. The opportunity is significant: fewer ingredients, cleaner labels, longer fluid life, reduced waste, and better alignment with customer and regulatory expectations. The watch-out is equally clear: multifunctionality only creates value when it is proven across performance, compatibility, exposure, and compliance—not when it is assumed.

Sources 

• UL Prospector — “Lubricant additives: Properties, functions, and applications.”

• UL Prospector — “Formulating Water-Based Metalworking Fluids in the 21st Century.”

• UL Prospector — “Lubricants & Metalworking Fluid Ingredients.”

• EPA — TSCA Section 8(a)(7) PFAS reporting rule.

• ECHA — Updated PFAS restriction proposal.

• OECD — PFAS and alternatives in hydraulic oils and lubricants.

• OSHA — 2024 Hazard Communication Standard final rule.

• UNECE — GHS Revision 11.

• ECHA — New CLP hazard classes.

• OSHA and NIOSH — Metalworking fluid exposure and best-practice materials.

• ECHA BPR and EPA antimicrobial pesticide registration.

• European Commission — EU Ecolabel for lubricants and Chemicals Strategy for Sustainability.

• EPA — Environmentally Acceptable Lubricants.

• South Coast AQMD Rule 1144.

• STLE / TLT — Bio-based additive advancements, lubricant additives, EV fluids, and water-based MWF formulation.

The views, opinions and technical analyses presented here are those of the author or advertiser, and are not necessarily those of ULProspector.com or UL Solutions. The appearance of this content in the UL Prospector Knowledge Center does not constitute an endorsement by UL Solutions or its affiliates.

UL Solutions does not make any representations or warranties with respect to the accuracy, applicability, fitness or completeness of the content. UL Solutions does not warrant the performance, effectiveness or applicability of sites listed or linked to in any content.

Share this article:     