LUBE OIL ADDITIVES

LUBRICANTS Lubricants were in use before the invention of wheel. Building block of 95% of today’s lubricants is mineral oil. Straight run MO not satisfactory for operating under arduous conditions. Modern Lubricant is highly refined HC base stock+chemical additives.

WORLD LUBRICANT USES 4 Automotive Transmissions 5 Grease 9 Process 27 Industrial 55 Engine % APPLICATION

PERFORMANCE-WISE CLASSIFICATION OF ADDITIVES Modifies crystal growth at low temperature Pour Point Depressants Improves viscosity – temp. relationships Viscosity Index Improvers Prevent formation of acid, minimize viscosity increase Antioxidant Reduce wear, minimize metal to metal contact Antiwear/EP Engine Cleanliness, keep sludge in suspension Detergents Dispersants

PERFORMANCE-WISE CLASSIFICATION OF ADDITIVES Control Foamings Defoamant Improves Adhesive Properties Tackiness Agents Neutralizes Catalytic Effect of Metals Metal Deactivators Prevent Corrosion of Ferrous and Non-ferrous surfaces Corrosion/Rust/ Inhibitors Reduce Friction between moving parts, improve engine efficiency Friction Modifiers

DETERGENT/DISPERSANT ADDITIVE Major Use in Crankcase Oil Represent 70% of Total Additive Used in Engine Oil

FUNCTION OF DETERGENT/ DISPERSANT ADDITIVE Keep Particulate matter dispersed Maintain Engine Cleanliness DIRT IN ENGINE ARISES FROM Below-by of products from incomplete combustion of fuel Oil oxidation product Engine wear Dirt Leads to Deposit in Engine e.g. On Piston Known as Lacquer or Varnish on English Sump Known as Sludge

DETERGENTS Metal Containing Cleaning Agents Capable of dealing deposits/precursor generated under high temperature running conditions

PARTS OF DETERGENT A metal Al, Mg, Zn, Ba, Ca. An anionic component e.g. carboxylate, Alcoholate, Phenate, Sulphonate and Salicylate. Oil Soluble Oleo-philic Component Straight or Branched Alkyl Group.

TYPES OF DETERGENTS Sulphonate By-product of white oil Phenate Salicylate Phosphate Neutral Over Base By-product of white oil Synthetic From Alkyl Aromatic

OVER BASE ADDITIVES Colloidal Disperson Of Metal Carbonate (10-3-1 Micron) TECHNOLOGY IS COMPLEX TO MAKE STABLE SUSPENSION ESTIMATION As TBN (500) Metal Ratio EFFECTIVE IN CONTROLLING a) Corrosive Acid From Oil Oxidation b) Blow-by Of Combustion Product

PREPARATION OF OVER BASE ADDITIVE Phenate Over Base Are Prepared Similarly Phosphates are Phosphoric And Thio Phosphoric Acid Derivatives

SELECTION DEPENDS ON Severity Of Condition Anti Rust Anti Oxidant Load Carrying Properties

DISPERSANTS Non metallic ashless cleaning agents Effective in controlling cold-sludge in gasoline engine operating under low-temp. stop-start conditions Bipolar molecule having polar head non-polar tail Head consist of P,O,N atoms Tail HC moiety

ADDITIVES TYPES Succinimides Succinate Esters Mannich Type Phosphorus Based

MECHANISM OF ACTION Polar Group Absobs on Dirt Oliophillic Group Solubilize Complex in Oil React Dirt Precursors e.g. neutralizing acidic matter Solubilizing precursors within their micelle structure. Absorb on metal surface Form coating on solid particulate and prevent their agglomeration to form large particles.

USES OF DETERGENT / DISPERSANT ADDITIVES Essential for most of automotive oils Automotive oil for gasoline/diesel Rail road engine oil Marine Oil Two stroke engine Tractor Oil Automatic Transmission Fluid

OXIDATION INHIBITOR (AO) Lubricants like other natural products deteriorate during use when exposed to oxygen. Undergo complicated aging process. Oxidation alter performance. 1st oxidation product is hydroperoxides. Hydroperoxide leads to variety of end products like alcohol, aldehyde, ketone acid etc. Eventually depositing as sludge, varnish, liquer. Leading to equipment failure

MECHANISM OF ACTION R-H R` + H` R` + O2 ROO` Antioxidant perform as radical quenchers R` + AO RH + AO` 2 AO` INERT PRODUCTS

Engine oil accounts 60-70% of automotive lubricants. 40-50% of all lubricants sold Automotive engine oil driving force on AO market AV car temperature – 100o Hot spot temperature – 300o or more Chain branching reactions are more prevalent in high temperature oxidation. For lube antioxidants is a mixture of peroxide destroyer (TDDP) and radical scavenger.

ADDITIVE TYPE Zn-Di-Thio phosphate Phenol Aromatic Nitrogen Compounds S- and P- Based Antioxidants Phenothiazine and Alkyl Derivatives

USES OF ANTIOXIDANTS Antioxidants are used in all type of Lubricant Cranckase Oil Mostly Use ZDDP Steam Turbine Hindered Phenol Jet Air Phenothiazine Derivatives

OTHER COMPUNDS GENERALLY USED IN ADDITION TO ZDDP HINDERED PHENOL RO – P – H OR O CH2 RO OH DIPHENYL AMINE NH C8H17 RO – P – OR OR N S R PHENOTHIAZINE DITHIOCARBAMATES CNX2 S – M – S X2NC S X= Alkyl, Aryl, alkylaryl ORGANIC SULPHIDE OR SLENIDES (XOC – CH2 – CH2)2 S, X – S – X, or X – Se - X O

VISCOSITY INDEX IMPROVER AND POUR POINT DEPRESSANTS These are polymeric additives These additives are used to improve rheological properties of oils They do it by purely physical means

VISCOSITY INDEX IMPROVER VI is a number showing viscosity temperature characteristic of oil. Gear, Transmission, Crankcase oil should have (a) Low viscosity at low temperature for startup (need low friction drag) (b) Sufficient viscosity at higher running temperature.

TYPES OF VI IMPROVERS Oil Soluble Org. Polymer M wt range 50,000-150,000 (a) Hydrocarbons (b) Esters

TYPES OF VI IMPROVERS HYDROCARBON TYPE PIB Poly-isobutylene OCB Olefin Co-polymer Poly Alkyl Styrene HSDC Styrene Butadiene Co-polymer Styrene – Isoprene Co-polymer ESTER TYPE PMP [Poly Alkyl Acrylate Styrene Maleic Acid Copolymer]

USES OF VI IMPROVERS PMA 21%, HSDC 17%, OCP 67% VI improver made possible the advent of multigrade oils e.g. SAE low 30 or SAE 15w40 for gasoline engine (67%) diesel engine (19%).

SELECTION DEPEND ON Requirement Other prop e.g. PPD, Dispersant Shear Stability Oxidation Thermal Stability

MECHANISM OF VISCOSITY MODIFICATION IN OIL Oil associated with polymer Polymer LOW Solubility GOOD Temperature LOW HIGH Exist as random coil Swollen by lube oil Volume determine viscosity increase At low temp. polymer remain as compact mass At high temp. coil open up Compensate fall in viscosity

USES OF VI IMPROVERS Automotive multi grade oils (engine, gear) Gear and transmissions oils Hydraulic fluids Industrial oils Dosage 2-6%

POUR POINT DEPRESSANTS At low temperature wax crystalize out and prevent flow of oil Dewaxing can reduce pour point - Reduces yield - Adversely effect VI PPD – syn chemical which prevent congelation PPD offer effective and economical alternative to dewaxing PPD improve - Low temperature fluidity - Low temp performance PPD mainly used in paraffinic oils

TYPES OF PP DEPRESSANTS Non Polymeric Polymeric Recent Lit. indicate that majority of products are poly hydrocarbon HC-Ester co-polymer and ester co-polymer

MECHANISM OF ACTION (POUR POINT DEPPRESANT) PPD don’t’ prevent crystallization Change crystal habit Probably by adsorption Smaller crystals form Do not interlock Permit flow of oil

USES OF PP DEPRESSANTS Mono and multi grade Oil Gear & Transmission oil Hydraulic Fluid Compressor Oil Machinery Oil

LOAD CARRYING ADDITIVES (AW/EP) Aw and EP additives are incorporated to extend oil’s load carrying capabilities Important but less used Inter metallic contact occur at asperities under boundary lubrication resulting heavy wear

TYPES OF ADDITIVES Additive are active compounds of S,Cl and P S-Compounds Dibenzyl disulfide Butyl phenol disulfide Sulfurised vegetable oils Pb, Sb, Cd and Zn dithiocarbamates Cl – Compounds Chlorinated wax Chlorinated fatty acids

TYPES OF ADDITIVES P - Compounds Tri cresyl phosphates ZDDP Di-alkyl phosphates etc P & S-Compounds Zinc dialkyl dithio phosphates Cl & S - Compounds Chlorinated alkyl sulfide Sulfurised chloronaphthalene

MECHANISM OF ACTION Act by physical adsorption, chemisorption or chemical reaction with metal forming protective film Film not penetrated by asparities Prevent scoring and surface damage

USES OF AW/EP ADDITIVES Engine oil Gear and transmission oil Shock absorber oil Hydraulic oils

FRICTION MODIFIERS (FM) During start-up and shut-down sliding surfaces subjected to high load (mixed friction range) FM additives used, to prevent stick-slip oscillation, noise and reduce frictional force To save energy, reduce fuel consumption (additives known as FM) FM Similar to AW/ EP Additives

TYPES OF FRICTION MODIFIERS FM are polar oil soluble materials Only few gained commercial Acceptance Mo-dithiophosphate and carbonate complexes Dispersion of MoS2, graphite, PTFE Ash less carboxylic acid esters, their oligomers and amines, amides

MECHANISM AND USES Mechanism By physical adsorption Uses Engine oil Gear and transmission oil Industrial oil greases, etc.

ANTIFOAMING AGENTS Requires where violent churning or agitation of oil occur Effect of Foams on the Performance of Engine Rise oil level,results in loss of oil Oil feed pressure drops, Insufficient oil supply

TYPES OF ADDITIVES POLYMERIC i) Poly organo siloxane CH3 CH3 CH3 Si O Si O Si O ii) Poly acrylate Iii) poly ethylene oxides DOSAGE 4-15 ppm n

MECHANISM OF ACTION Oil insoluble Lower interfacial tension between air and oil Permitting easy aggregation of air Reduce foam stability

USES ANTIFOAMING AGENTS Engine oils (automotive, rail, marine) Gear oils Automotive transmission fluids Industrial oils Metal working oils

RUST AND CORROSION INHIBITORS Rust and corrosion of metal parts undesirable Leads to wear and break down

RUST INHIBIOTRS RESULT OF CHEMICAL ATTACK OF WATER IN PRESENCE OF OXYGEN

TYPES OF RUST INHIBITORS A large variety of compounds patented mostly three types: a. Neutral b. Acidic c. Overbased Most Popular are High mil. Wt. Carboxylic acid (Succinic acid) Sulphonic acid Phosphoric acid and their salts Compounds formed by neutralization of these acids with organic base (e.g. Amines)

MECHANISM OF ACTION Physical Means Work by forming strongly absorbed hydrophobic film

CORROSION INHIBITORS Corrosion occur due to attack of acid Arising from A) oil oxidation (org>) B) blow-by of combustion products (SO2 inorg) Later sever in diesel engine

ADDITIVE TYPES Metal dialkyl dithio phosphates, Phospho sulphurized olefins, terpenes Org Phosphites, Dithio carbamate Most popular are basic detergent / dispersant additive

MECHANISM OF ACTION Forming absorbed protective films By neutralizing acid materials Also acts as Antioixdants, load-carrying additives

MISCELLANEOUS LUBE ADDITIVES Anti-microbial agents used in cutting oil emulsions Emulsifiers to manuf. Water based cutting oils Odour masking agents Dyes for identifications

MISCELLANEOUS ADDITIVES Tackiness agents impart stickiness/ adherence property (PIB, ethylene-propylene co-polymer) Seal swalling agent to help swalling of rubber elastomers to required volume (phthalic acid ester, most popular di-octyl phthalate [DOP]

SOME GENERAL TYPE OF ADDITIVES USED IN A WIDE VARIETY OF LUBRICANTS  Seal Swell Pour Point Viscosity Improvers Antifoam Agents Extreme Pressure Agents Friction Modifiers Corrosion Inhibitors Rust Inhibitors Antiwear Agents Antioxidant Ashless Dispersant Metallic Detergent Metal Working Fluids Turbine Oils Gear Oils Hydraulic Oils Axle Oils Automatic Trans. Fluid Engine Oil LUBRICANT TYPE ADDITIVE