Olefin Sulfides in Lubricant Additives

Introduction 

Lubrizol provides leading lubricant additive technologies for applications where there are harsh mechanical conditions and where there is a need to provide innovative solutions to meet the varying needs of specific applications. This is particularly important due to the widely ranging variables in some uses. Because of its exceptional knowledge, technical facilities, and people, Lubrizol is able to provide olefin sulfides that support the needs of global industries by improving the operating efficiency and the useful life of many types of equipment. These additives also provide added value to customers' products helping them differentiate themselves from their competitors.

Applications

Olefin sulfides are one class of lubricant additives used for controlling wear in ashless lubricant systems particularly for extreme pressure conditions in auto and industrial gears. They also are used in greases, marine oils, metal processing oils and tractor transmission oils. These chemicals are combined with other lubricant additives and highly refined base oil in the formulated end use product. They have very good thermal oxidation stability and rust inhibition properties. Olefin sulfides prevent wear by preventing contact between metal surfaces via film formation and smoothing of the metal surfaces.

Physical and Chemical Properties

Olefin sulfides are composed of saturated alkyl chains, linear or branched, that contain one or more covalently bonded molecules of sulfur. Molecular weights range from 200 to 2000 Dalton. They are liquids that have a low vapor pressure and a low propensity to enter the air. Olefin sulfides are insoluble in water and generally have a high octanol/water partition coefficient. They have a strong sulfur odor and are normally stable at moderately elevated temperatures and pressures.

Health Effects

In general, olefin sulfides have a low order of acute oral and dermal toxicity. However, olefin sulfides can cause skin, eye and respiratory irritation and certain forms are dermal sensitizers. Studies in rats show that repeated inhalation of some olefin sulfides at high concentrations can cause effects in the liver, lungs, kidneys and nasal turbinates at high concentrations. Genotoxicity testing indicates that olefin sulfides are not mutagenic and do not cause adverse chromosomal effects. While olefin sulfides have not been tested in carcinogenicity studies, the genotoxicity studies indicate that they do not pose a carcinogenic hazard.

Environmental Effects

The environmental hazards of olefin sulfide additives have been well studied in vertebrate and invertebrate species. The acute aquatic toxicity in fish, daphnia and bacteria ranges from low to moderate. Studies indicate that they exhibit limited to moderate biodegradability.

Regulatory Information

These additives are subject to the European Commission REACH (Registration, Evaluation, Authorisation and Restriction of Chemical substances) regulation, which was implemented to ensure that chemicals in commerce are safe for man and the environment. The registration and submission of Chemical Safety Reports for these substances will be submitted to the European Chemicals Agency (ECHA) by Lubrizol in accordance with the applicable deadline. Olefin sulfides have been tested and reviewed under the U.S. EPA High Production Volume (HPV) Challenge Program. As noted in Lubrizol material safety data sheets, olefin sulfides have gained acceptance in major industrialized countries through global notifications. Some products also have transportation requirements.

Exposure Potential

Lubrizol olefin sulfide additives are sold to industrial customers who formulate lubricants and greases. Workers in these industrial exposure scenarios can be exposed to these products via dermal and inhalation routes. Some operations are conducted under elevated temperatures that increase the potential for inhalation exposure. Because the formulated products contain low level of olefin sulfides, the exposure potential for professional workers and consumers generally are much lower. The extent of exposure varies depending on the use conditions such as closed systems and the duration and frequency of use.

Risk Management

Information on the safe handling of these products is provided to workers who make the products and who formulate lubricants and greases 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 and gloves with training are used to avoid skin contact.

Conclusion

Lubrizol olefin sulfide additives are designed to meet a wide range of performance needs, particularly at extreme pressures. Their excellent physical and functional properties make them ideal for use in lubricants and greases where thermal oxidation stability and rust inhibition properties are important.

Olefin sulfides have a low order of acute oral and dermal toxicity. However, some products can cause skin, eye, and respiratory irritation and dermal sensitization. Some also may cause long-term adverse effects on the aquatic environment. These risks are effectively managed by the use of appropriate engineering controls, work practices, personal protective equipment, and environmental release controls.