252 Lubricant Additives: Chemistry and Applications
9.5.2 Grease ........................................................................................................................ 271
9.5.3 Industrial Oils ............................................................................................................ 271
9.5.3.1 Industrial Gear Oils .................................................................................... 272
9.5.3.2 Slideway Oils .............................................................................................. 272
9.5.3.3 Hydraulic Fluids .......................................................................................... 272
9.5.3.4 Multifunctional Lubricants ......................................................................... 272
9.5.3.5 Agricultural Applications ........................................................................... 272
9.5.3.6 Automotive Applications ............................................................................ 272
9.5.4 Synergies/Compatibility with Other Additives ......................................................... 273
9.5.4.1 Zinc Dialkyldithiophosphates ..................................................................... 273
9.5.4.2 Basic Alkali Metal Salts ............................................................................. 274
9.5.4.3 Antioxidants ................................................................................................ 274
9.5.4.4 Esters/Triglycerides .................................................................................... 274
9.5.5 Cost-Effectiveness ..................................................................................................... 2 75
9.6 Manufacture and Marketing Economics ............................................................................... 275
9.6.1 Manufacturers ............................................................................................................275
9.6.2 Marketers ................................................................................................................... 276
9.6.3 Economics ................................................................................................................. 276
9.6.4 Government Regulations ........................................................................................... 276
9.6.4.1 Competitive Pressures ................................................................................. 276
9.6.4.2 Product Differentiation ............................................................................... 276
9.7 Outlook .................................................................................................................................. 276
9.7.1 Crankcase/Automotive Applications ......................................................................... 276
9.7.2 Industrial Applications .............................................................................................. 277
9.8 Trends .................................................................................................................................... 277
9.8.1 Current Equipment/Specifi cation .............................................................................. 277
9.8.1.1 Types of Equipment .................................................................................... 277
9.8.1.2 Additives in Use .......................................................................................... 277
9.8.1.3 Defi ciencies in Current Additives ............................................................... 277
9.9 Medium-Term Trends ............................................................................................................ 278
9.9.1 Metalworking ............................................................................................................ 278
9.9.2 Industrial Oils ............................................................................................................ 278
References ...................................................................................................................................... 278
9.1 INTRODUCTION
In the lubricant industry, a great variety of sulfur-containing additives are known and in use today.
We list only a few of the most common types:
Sulfur carriers (sulfurized olefi ns, esters, and fatty oils)
Sulfur/phosphorus derivatives (dithiophosphates, thiophosphonates, thiophosphites, etc.)
Thiocarboxylic acid derivatives (dithiocarbamates, xanthogenates, etc.)
Heterocyclic sulfur (mercaptobenzothiazoles, thiadiazoles, etc.)
Sulfonates (Na-, Ca-salts of alkylbenzenesulfonic acids, nonylnaphthalenesulfonates, etc.)
Others (sulfated fatty oils/Turkish red oils, sulfurchlorinated fatty oils, sulfur-linked phe-
nols and phenates)This long list gives a good impression of the versatility and importance of sulfur chemistry in lubri-
cants. But as versatile their chemistry is, the range of applications of sulfur-containing lubricant
additives is just as versatile. In this chapter, we try to review major aspects of a group of additives
commonly known as sulfur carriers. This is a generic name that has been accepted in the marketplace
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