LUBE OIL ADDITIVES

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LUBE OIL ADDITIVES
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LUBRICANTS

• Lubricants were in use before the invention of
  wheel.
• Building block of 95 of todays lubricants is
  mineral oil.
• Straight run MO not satisfactory for operating
  under arduous conditions.
• Modern Lubricant is highly refined HC base
  stockchemical additives.

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WORLD LUBRICANT USES
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PERFORMANCE-WISE CLASSIFICATION OF ADDITIVES
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PERFORMANCE-WISE CLASSIFICATION OF ADDITIVES
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DETERGENT/DISPERSANT ADDITIVE

• Major Use in Crankcase Oil
• Represent 70 of Total Additive Used in Engine
  Oil

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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

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DETERGENTS

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

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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.

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TYPES OF DETERGENTS

• Sulphonate
• Phenate
• Salicylate
• Phosphate
• Neutral
• Over Base

By-product of white oil
Synthetic From Alkyl Aromatic
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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

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PREPARATION OF OVER BASE ADDITIVE

• Phenate Over Base Are Prepared Similarly
• Phosphates are Phosphoric And Thio Phosphoric
  Acid Derivatives

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SELECTION DEPENDS ON

• Severity Of Condition
• Anti Rust
• Anti Oxidant
• Load Carrying Properties

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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

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ADDITIVES TYPES

• Succinimides
• Succinate Esters
• Mannich Type
• Phosphorus Based

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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.

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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

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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

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R-H R HR O2
ROOAntioxidant perform as radical
quenchersR AO RH AO2 AO
INERT PRODUCTS
MECHANISM OF ACTION
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• 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.

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ADDITIVE TYPE

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

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USES OF ANTIOXIDANTS

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

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OTHER COMPUNDS GENERALLY USED IN ADDITION TO ZDDP
HINDERED PHENOL
DIPHENYL AMINE
PHENOTHIAZINE
DITHIOCARBAMATES
X Alkyl, Aryl, alkylaryl
ORGANIC SULPHIDE OR SLENIDES
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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

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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.

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TYPES OF VI IMPROVERS

• Oil Soluble Org. Polymer
• M wt range 50,000-150,000
• (a) Hydrocarbons
• (b) Esters

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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

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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).

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SELECTION DEPEND ON

• Requirement
• Other prop e.g. PPD, Dispersant
• Shear Stability
• Oxidation Thermal Stability

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MECHANISM OF VISCOSITY MODIFICATION IN OIL
Oil associated with polymer
Polymer
Solubility
LOW
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

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USES OF VI IMPROVERS

• Automotive multi grade oils (engine, gear)
• Gear and transmissions oils
• Hydraulic fluids
• Industrial oils
• Dosage 2-6

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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

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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

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MECHANISM OF ACTION (POUR POINT DEPPRESANT)

• PPD dont prevent crystallization
• Change crystal habit
• Probably by adsorption
• Smaller crystals form
• Do not interlock
• Permit flow of oil

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USES OF PP DEPRESSANTS

• Mono and multi grade Oil
• Gear Transmission oil
• Hydraulic Fluid
• Compressor Oil
• Machinery Oil

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LOAD CARRYING ADDITIVES (AW/EP)

• Aw and EP additives are incorporated to extend
  oils load carrying capabilities
• Important but less used
• Inter metallic contact occur at asperities under
  boundary lubrication resulting heavy wear

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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

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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

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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

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USES OF AW/EP ADDITIVES

• Engine oil
• Gear and transmission oil
• Shock absorber oil
• Hydraulic oils

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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

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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

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MECHANISM AND USES

• Mechanism
• By physical adsorption
• Uses
• Engine oil
• Gear and transmission oil
• Industrial oil
• greases, etc.

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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

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TYPES OF ADDITIVES

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

n
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MECHANISM OF ACTION

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

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USES ANTIFOAMING AGENTS

• Engine oils (automotive, rail, marine)
• Gear oils
• Automotive transmission fluids
• Industrial oils
• Metal working oils

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RUST AND CORROSION INHIBITORS

• Rust and corrosion of metal parts undesirable
• Leads to wear and break down

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RUST INHIBIOTRS

• RESULT OF CHEMICAL ATTACK OF WATER IN PRESENCE OF
  OXYGEN

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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)

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MECHANISM OF ACTION

• Physical Means
• Work by forming strongly absorbed hydrophobic film

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CORROSION INHIBITORS

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

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ADDITIVE TYPES

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

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MECHANISM OF ACTION

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

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MISCELLANEOUS LUBE ADDITIVES

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

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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

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SOME GENERAL TYPE OF ADDITIVES USED IN A WIDE
VARIETY OF LUBRICANTS