Polymethacrylate Rheology Additives


Lubrizol is the largest supplier of viscosity modifiers and pour point depressants.  These market-leading viscosity modifier and pour point depressant technologies are an integral part of the most extensive portfolio of advanced additive technologies designed to meet our customers' needs.  Lubrizol has utilized its world class research and development capabilities to develop products that meet not only basic specification needs but to provide the most differentiated and premium products.


Polymethacrylates (PMAs) are used in both viscosity modifier and pour point depressants, key ingredients in lubricating oils and other fluids.  PMA viscosity modifiers are used to increase the viscosity index of the lubricant and, therefore, to provide it a more stable viscosity over a broad temperature range in crankcase, driveline, and hydraulic oils/fluids.  Pour point depressants are designed to keep oil flowing in cold weather.  They keep waxes, which are present in nearly all refined mineral oils, from forming interlocking crystals that can prevent the fluid from flowing.  The chemistry of the specific PMA must be matched to the fluid and application. 

Physical and Chemical Properties

PMAs are produced by polymerizing the desired methacrylate monomers.  A highly refined lubricant base oil is used as a solvent during the manufacturing process and remains in the final product to maintain stability and physico-chemical properties.  PMAs are high molecular weight polymers with molecular weights typically greater than 10,000 Daltons.  They are not expected to partition into water or air because of their low water solubility and low vapor pressure.

Health Effects

The health effects of PMAs have been assessed as part of the Canadian Domestic Substance List categorization process.  They do not meet the criteria for being categorized as a health concern.  PMAs are not expected to be skin or eye irritants or skin sensitizers.  Based on their high molecular weight they are not expected to be absorbed via skin contact or accidental ingestion, and therefore, are expected to have a low order of concern for acute and repeat dose toxicity.  Because of their low vapor pressure, the potential for inhalation exposure is limited.  They are not expected to be genotoxic or carcinogenic.

Environmental Effects

The environmental effects of PMAs also have been assessed as part of the Canadian Domestic Substance List categorization process.  They do not meet the criteria for being categorized as an environmental concern. They are not readily biodegradable and are not expected to be toxic to aquatic organisms.  Because of their high molecular weight and low water solubility, water is not a target compartment, limiting the potential for bioaccumulation. 

Regulatory Information

PMA monomers and other reactants currently are subject to the European Commission REACH (Registration, Evaluation, Authorisation and Restriction of Chemical substances) regulation. Lubrizol is working with suppliers to insure that the registrations and Chemical Safety Reports for these substances are submitted to the European Chemicals Agency (ECHA) in accordance with the applicable deadlines. As noted in Lubrizol safety data sheets, PMAs have gained acceptance in major industrialized countries through global notifications. 

Exposure Potential

Lubrizol PMAs are sold to industrial customers who formulate engine oils and other fluids.  Workers in these industrial exposure scenarios, professional workers and consumers can be exposed to PMAs via dermal contact.  The potential for inhalation exposure is limited by their low volatility.  However, some industrial operations that are conducted under elevated temperatures may increase the potential for inhalation exposure.  Because formulated products and the end use fluids contain relatively low levels of PMAs, the exposure potential for professional workers and consumers generally is much lower.  The extent of exposure varies depending on use conditions such as closed systems and the duration and frequency of use.  The potential for oral exposure is limited to cases of accidental ingestion. Indirect exposure via environmental media is expected to be negligible because of their low water solubility, low volatility and relatively low levels in formulated products.

Risk Management

Information on the safe handling of these products is provided to workers who make the products and who formulate engine oils and other fluids through dissemination of material safety data sheets.  These documents provide a broad range of safety information including hazard warnings and risk management measures.  They note engineering controls, work practices, and personal protective equipment that are needed during the manufacture and formulation to control exposures. Good industrial hygiene practices also are used to avoid skin contact.  Environmental risk is mitigated by controlling spills and environmental releases. 


Lubrizol PMAs are designed to meet the special rheology needs of engine oils and other fluids.  Their excellent physical and functional properties make them ideal for use in lubricant and hydraulic fluids to increase stability at high temperatures and keep oil flowing in cold weather.  PMAs have been assessed under the Canadian Domestic Substance List categorization process.  They have been determined to be of low health and environmental concern.   The use of appropriate engineering controls, work practices, personal protective equipment and environmental release controls and practices provides effective risk management.