CRC HANDBOOK OF LUBRICATION (Theory and Practice of Tribology)

E. Richard Booser, Editor

Volume I Application and Maintenance

Applications Industrial Lubrication Practices

Maintenance Appendixes

Volume I1 Theory and Design

Friction, Wear, and Lubrication Theory Lubricants and Their Application

Design Principles

TABLE OF CONTENTS

FRICTION. WEAR. AND LUBRICATION THEORY The Shape of Surfaces ...................................... .-. ........................... 3 Properties of Surfaces 17 Friction 31

Hydrodynamic Lubrication 69

Hydrostatic Lubrication 105

................................................................... ..................................................................................

Boundary Lubrication ................................................................... 49

Numerical Methods in Hydrodynamic Lubrication ...................................... 93

Squeeze Films and Bearing Dynamics .................................................. 121 Elastohydrodynamic Lubrication ....................................................... 139

Wear of Nonmetallic Materials ......................................................... 185

..............................................................

.................................................................

.......................................................................... Metallic Wear 163

Wear Coefficients ...................................................................... 201 Lubricated Wear 209 ........................................................................

LUBRICANTS AND THEIR APPLICATION Liquid Lubricants ...................................................................... 229 Lubricating Greasedharacteristics and Selection .................................... 255

Properties of Gases ....... .............................................................. @ Lubricating Oil Additives ............................................................

Metal Processing-Deformation ........................................................ 317 Metal Removal ......................................................................... 335

utting Fluids .......................................................................

Lubricant Application Methods .......................................................

........................................................................ Solid Lubricants 269 J 291

--F + C u t t i n g Fluids-Microbial Action ...................................................

................................................................ Circulating Oil Systems 395

DESIGN PRINCIPLES Journal and Thrust Bearings ............................................................ 413 Sliding Bearing Materials .............................................................. 463 Sliding Bearing Damage ................................................................ 477 Rolling Element Bearings .............................................................. 495

Mechanical Shaft Couplings ............................................................ 565

Wear Resistant Coatings and Surface Treatments ....................................... 623 Systems Analysis ....................................................................... 645

................................................................................... Gears 539

Dynamic Seals 581 .........................................................................

-7 INDEX ................................................................................. 665 G

VolurneII 301

LUBRICATING OIL ADDITIVES

J. A. O'Brien

INTRODUCTION

The modem history of lubricant additives began in the early 20th century with the use of fatty oils and sulfur in mineral oils to improve lubrication under high loads. World War I1 provided a major impetus to the development of lubricant additives as the military, engine bllilders, and machine manufacturers demanded more performance from their equipment.

C',)nsumption of lubricant additives in the U.S. increased from 127 thousand metric tons in 1950 to 710 thousand metric tons in 1978., Lubricants for internal combustion (IC) engines account for 72% of the market. Total free-world consumption of lubricant additives is estimated to be about three times that of the U.S.

The unique feature of IC engine lubricants is their exposure to combustion products from blow-by, fuel combustion products which leak past piston rings and contact the lubricant. Blow-by contains unbumed fuel, reactive intermediates of fuel oxidation, fixed nitrogen in the forms of nitrogen oxides, and their fuel reaction products, soot, products of fuel additives, wllrir oxides, carbon monoxide, carbon dioxide, and water. IC engine lubricants require . .:L :,.ive additive treatment to counteract the effects of blow-by, such as internal engine ~ U S I , bearing corrosion, surface deposits which interfere with engine clearances, sludge lormation which blocks lubricant passages, and lubricant decomposition.

Some industrial lubricants, such as those used in a steel or paper mill, also encounter severe environments and contamination. Extemal and internal environments may subject lubricants to severe oxidizing conditions, extreme pressures and temperatures, water, dust, metal catalysts, and active chemicals.

ADDITIVE FUNCTIONS

klany minerals are used as lubricant additives, far too many to list in detail. Ramney published three text^*.^*^ listing recent additive patents. This chapter discusses some of the more widely used additives, emphasizing their primary performance characteristics. Chem- ical structure and manufacture of some major lubricant additives are included in the Appendix.

Boundary Lubrication Additives In boundary lubrication, surface asperities contact each other even though the lubricant

supports much of the load. Friction depends mainly on the shearing forces necessary to L,!~::I\T these adhering asperities and wear and friction can be reduced by certain additives. ['able 1 lists common boundary lubrication additives.

Wear inhibitors and lubricity agents are polar materials that adsorb on a metal and provide a film that reduces metal-to-metal contact. Extreme pressure (EP) uddirives are a special class of boundary lubrication additive which react with the metal surface to form compounds with lower shear strength than the metal. This low-shear compound provides the lubrication. Friction modifiers can either adsorb or react with the surface to reduce friction by forming a very low shear-strength film. For example, Figure 1 demonstrates the effect of a friction modifier in an automatic transmission fluid. Without a friction modifier, the friction Cwf- f k n t in the transmission would increase at low-sliding velocity where surface asperities Inak contact. This would result in rough shifting and lead to high-transmission loading and driver discomfort in vehicles. n e friction modified fluid now in common use permits smooth shifting at low speeds while it maintains adequate friction under normal driving to prevent

Volume I1 303

10

3 Y

g - 8 -J

$ 0 a a 7 .- In w

6

5

Without

With Friction Modifier

I I I I I I I I I I I J 30 40 50 60 70 80 90 100 110 120 130 140 150

Crankcase Temperature, OC

FIGURE 2. Effect of friction modifier in engine crankcase lubricant.

Table 2 CORROSION INHIBITORS

Zinc dithiophosphates Other dithiophosphates Metal sulfonates Overbased metal sulfonates Metal phenate sulfides Overbased metal phenate sulfides Fatty acids Acid phosphate esters Chlorinated wax Amines 2,4-Bis (alkyldithi0)- 1,3,4-thiadiazoles Alkyl succinic acids

or (2) deactivate corrosive contaminants in the lubricant. Certain additives that inhibit cor- rosion in some environments can actually cause corrosion in others. For example, zinc dithiophosphates inhibit copper-lead bearing corrosion in an oxidative environment, yet cause silver bearing distress from sulfidation. When used in high concentrations, zinc dialkyldi- thiophosphates can also pit some ferrous metals.

Oxidation Inhibitors Oxidation, the most common form of lubricant deterioration, proceeds through free-radical

reactions which are accelerated by heat and catalyzed by metals. In hydrocarbon lubricants, free-radicals react with oxygen to form proxy free-radicals which attack hydrocarbons to forfn new free-radicals and hydroperoxides. Free-radicals are formed faster than they are used and the rate of oxidation increases.

Some hydroperoxides decompose into aldehydes, ketones, carboxylic acids, and other Oxygen-containing hydrocarbons. The oxygen compounds polymerize to form viscous soluble materials (lubricant thickening) and insoluble materials (sludge and deposits.) Some of the Oxygen compounds are active, polar materials that accelerate rust and corrosion.

304 CRC Handbook of Lubrication

Table 3 OXIDATION INHIBITORS

Zinc dithiophosphates Metal dithiocarbamates Hindered phenols Phenol sulfides Metal phenol sulfides Metal salicylates Aromatic amines Phospho-sulfurized fats and olefins Sulfunzed olefins, fats, fat derivatives, paraffins,

Disalieylal- 1,2-propane diamine 2.4-bis (Alkyldithi0)- I ,3,4-thiadiazoles Dilauryl selenide

and carboxylic acids

Table 4 DETERGENTS AND DISPERSANTS

Detergents Dispersants

Metal sulfonates Polyamine succininrides Overbased metal sulfonates Metal phenate sulfides Polyamine succinamides Overbased metal phenate sulfides Metal salicylates Polyamine amide imidazolines Metal thiophosphonates

Hydroxy benzyl polamines

Polyhydroxy succinic esters

Table 5 VI IMPROVERS

Ethylene-propylene copolymers Polymethacrylates Styrene isoprene copolymers Styrene butadiene copolymers Styrene maleic ester copolymers Polyisobutylenes

Oxidation inhibitors (Table 3) generally function by one or more of three mechanis free radical inhibition, peroxide decomposition, or metal deactivation. Each mechani inhibits oxidation at a different link in the chain reaction. Hindered phenols, such as 2 di-t-butyl-pura-cresol (DBPC), are effective free-radical oxidation inhibitors react with free-radicals to form nonfree-radical compounds. Some sulfur co compose peroxides into stable compounds. Some selective polar additives reac ions and surfaces to inhibit their catalytic activity and are known as metal deactiva

Detergents and Dispersants Both detergent and dispersant additives (Table 4) are polar materials w

cleaning function. Detergency is a surface phenomenon of cleaning surface persancy is a bulk lubricant phenomenon of keeping contaminants suspended in the 1U

Detergent and dispersant additives each perform both of the above functions their relative ability to function at the machine surface or in the bulk of the 1

Viscosity Modifiers Viscosity index (VI) improvers (Table 5) are polymers that cause minimal

VolumII 305

Table 6 EFFECT OF VI IMPROVER

Viscosity SAE viscosity VI

grade Improver cSt at 100°C CP at - 18°C VI

40 No 14.0 I5000 100 l ow No 6.5 2000 100 IOW40 Yes 14.0 2350 I45

lubricant viscosity at low temperature, but considerable increase at high temperature. Table 6 demonstrates the effects of a VI improver. A typical 100 VI SAE 40 viscosity grade oil has proper viscosity (14 cSt) for engine lubrication at 100°C, but is too viscous (15OOO cP) to permit engine starting at - 18°C. A typical 100 VI SAE 1OW oil would permit engine starting at - 19"C, but is not viscous enough to protect the engine from wear at 100°C. By adding a VI improver to the SAE 1OW oil, the product can permit engine starting at - 18°C and still protect the engine from wear at 100°C.

Many of the same chemicals are also used as thickeners to increase the viscosity of products for special applications such as gear oils. Molecular weight may be varied to optimize specific performance characteristics. Viscous petroleum fractions, such as bright stocks, are also used as thickeners but are not considered additives.

Pour Point Depressants Petroleum oils contain paraffinic wax which crystallizes in a lattice-like structure as the

lubricant cools and prevents the lubricant from flowing. The lowest temperature at which the lubricant flows is called the pour point. Pour point depressants co-crystallize with the paraffinic wax, modify growth of the lattice-like structure, and permit flow at temperatures below the pour point of the unmodified lubricant. Common pour point depressants include: pol ymethacrylates, wax alkylated naphthalene polymers, wax alkylated phenol polymers, and chlorinated polymers.

Emulsion Modifiers Emulsifiers give stable emulsions of water-in-oil or oil-in-water. They are used where

high amounts of water improve cooling due to the high specific heat and thermal conductivity of water. Lubricants which contain water are increasingly being used to conserve petroleum base stocks.

Demulsifiers make emulsions unstable, which permits separation of water and lubricant. Ihey are particularly important where water contamination can damage the lubricant in marine or industrial applications. Emulsion modifiers change the interfacial tension of oil and water. Low-interfacial tension permits stable emulsions. Table 7 lists emulsion modifiers.

Foam Decomposers Excessive lubricant foaming can cause an overflow of the lubricating system, displace

lubricant in pumps, increase response time of hydraulic systems, and disrupt the lubricant Supply. Two theories predominate on the function of foam decomposers. The first is that they increase gas-lubricant interfacial tension to the point where the bubbles collapse. The

i s that these partially soluble compounds with low-surface tension cause openings In the bubbles which allow the gas to escape.

Foam decomposers function at concentrations from 1 to 50 ppm. High concentrations can Ifad to excessive foaming, more than the original lubricant, and increased air entrainment. Comt" foam decomposers include: polysiloxanes (silicones), polyacrylates, organic co- WlYmers, and candellilla wax.

I.

306 CRC Handbook of Lubrication

Table 7 EMULSION MODIFIERS

Emulsifiers Soaps of fats and fatty acids Low-molecular weight Na and Ca sulfonates Low-molecular weight Na and Ca naphthenates

Demulsifiers High-molecular weight Ca and Mg sulfonates Alkylene oxide denvatives Heavy metal soaps

Tackiness Agents Tackiness agents help the lubricant adhere to machine surfaces, or to itself, rather than

flow, splatter, leak, mist, or otherwise contaminate the surrounding area. Tackiness agents function through physical, viscoelastic phenomena by increasing low-shear viscosity and providing the lubricant with the ability to stretch into fibers. Common additives of this type include viscosity modifiers (Table 7), aluminum soaps of unsaturated fatty acids, and other soaps.

Seal Swell Agents Lubricants frequently contact elastomer seals, for example, in automatic transmissions.

Shrinkage of seals results in leaks while excessive swelling and softening cause wear or extrusion from the seal seat - again resulting in leaks. Most lubricants are intended cause a minor amount of seal swell to ensure sealing without excessive softening. Seal s characteristics usually depend on the base stock. If the base stock causes excessive s swell, additives can do very little to correct it. However, if the base stock shrinks the se the following seal swell additives can correct the problem: aromatics, aldehydes, keton and esters.

Dyes Dyes are occasionally used in lubricants to provide a distinctive, attractive, or uni

color. Dyes must be soluble in the lubricant, have high-coloring power and not be detrim to other lubricant properties.

LUBRICANT FORMULATION

Problems with Interactions

In some cases, individual additives are blended directly into the base oil. In other group of addifives are blended into an additive "package," which is subsequently into the base oil. Since most additives are active chemicals, they can interact in the or in the lubricant to form new compounds. These interactions can decrease tiveness and lead to insoluble or otherwise undesirable by-products.

example, zinc dithiophosphate (ZDTP) must be able to leave the bulk of adhere to the machine surface to function as a wear inhibitor, When a dis the same lubricant, the dispersant can hold the ZDTP in solution and prevent the functioning. Many lubricants require both ZDTP and dispersant. Dispers manufactured to minimize their ability to disperse ZDIT. Moreover, applications are selected to perform in the presence of a dispersant.

Most modem lubricants require more than one additive to meet all performance de

Additive functions frequently depend on their limited solubility in the 1

Surface active additives can also compete with each other. Both wear inhibit

Volume I1 307

Table 8 SF ENGINE LUBRICANT TESTS'

Test sequence Performance aspect

ASTM IID'O

ASTM IIIDI0

ASTM VD"

CRC L-38I2

Engine rust under short-trip, low-temperature

Oxidation, wear, and deposits under high-speed,

Overhead cam wear and sludge and varnish

Oxidation and bearing corrosion under high-

operation

high-temperature operation

deposits under stop-and go operation

temperature operation

Table 9 CD ENGINE LUBRICANT TESTS9

Test sequence Performance aspect

Caterpillar 1 -G2" Caterpillar I-D2'

CRC L-38'*

High-temperature diesel piston deposits High-temperature diesel piston deposits with

Oxidation and bearing corrosion under high- high-sulfur fuel

temperature. operation

a Proposed designation of a new test to replace the obsolete Caterpillar 1 - D1* test.

rust inhibitors function by adsorbing on metal surfaces and they compete for the same surface. The wear inhibitor can displace the rust inhibitor on the surface and be detrimental to rust inhibition. Likewise, the rust inhibitor can displace the wear inhibitor.

Meeting Performance Requirements Universal engine lubricants meet the performance requirements of passenger car gasoline

engines, as well as turbocharged two-stroke cycle and four-stroke cycle truck diesel engines. The additive package requires a very careful balance because it deals with diverse, complex quality requirements. Passenger car engine lubricant requirements in the U.S. are defined by a series of laboratory engine tests designated S P by the American Petroleum Institute (API). The SF designation signifies that the lubricant passed the tests shown in Table 8.

Truck diesel engine lubricant requirements in the U.S. are designated CD.9 To obtain the CD designation, the lubricant must pass the tests shown in Table 9. Most engine lubricant requirements outside the U.S. also require SF or CD performance plus additional local performance requirements.

Each SF and CD test stresses certain performance aspects of the lubricant and has been correlated with field experience. The IID test simulates short-trip winter driving, which is the most severe rust-forming condition, The IIID test simulates high-speed, high-load, and high-temperature driving conditions, such as towing a camper-trailer across the desert in the Summer at high speed, which are severe for oxidative thickening and wear. The VD test simulates continuous stop-and-go city driving with an overhead cam engine - a severe condition for sludge and vmish formation and cam wear. The 1 -G2 test simulates a heavily loaded, turbocharged, four-stroke diesel using high-sulfur fuel. The L38 test stresses pro- tection of copper-lead bearings from corrosion. In addition to passing all SF and CD tests, a universal engine oil must also have less than 1% sulfated ash to be compatible with two-

cycle diesel engine performance. Lubricant formulation involves handling all of these conditions with the same lubricant.

308 CRC Handbook of Lubrication

Table 10 EXAMPLE OF ADDITIVE EFFECTS IN UNIVERSAL ENGINE

LUBRICANT I

Gasoline engine Rust Lubricant oxidation Deposits Wear Bearing corrosion

Diesel Engine Piston deposits Fuel sulfur Low ash

+ + + +

- + + + - + + +

- - -

- + + + -

Additive

Overbased Low-based Performance aspect Dispersant ZDTP sulfonate sulfonate Phenate

+ + + + - - - +

- - - - -

+ + + + + + + + + + +

+ - -

Nore: Key: + + + , very beneficial; + + , beneficial; + , slightly beneficial; = , no effect; - , detrimental; and - - , very detnmental.

Table 10 shows how the additives commonly used in universal engine oils perform in the major aspects of the SF and CD sequence tests. Additive formulation for most lubricants involves similar consideration of beneficial and detrimental additive effects.

Relationship of Additives and Base Stocks

bility and response. For example, performance of surface active additives depends larg on their ability to adsorb on the machine surface at the proper time and place. Base st with p r solubility characteristics may allow these additives to separate before fulfill their intended functions. Conversely, base stocks with very high-solubilit teristics may keep the additives in solution, not allowing them to adsorb.

Additive response depends on base stock composition. Natural sulfur, nitrogen, phenolic inhibitors are removed along with undesirable materials during base stock refin Removal of these natural inhibitors often results in reduced oxidation inhibition relati unrefined stocks. However, the natural inhibitors, as well as the undesirable m removed during base stock refining, often interfere with additive performance.

Synthetic base oils, depending on their chemical structure, exhibit very specific soh characteristics, additive response, and additive compatibility that are sometimes diffe! from mineral oils. The most common synthetic base oils are synthetic hydrocarbons, as polyalpha olefins, and esters, such as adipate, azelate and pentaerythritol esters.

Synthetic hydrocarbons exhibit excellent additive response but are poor additive Esters vary in additive response and are excellent solvents except for additives . they react tofonn precipitates. Synthetic oils can be blended with each other or oil to provide the optimum balance of solubility and additive response.

Formulation

as well as individual additive performance and solubility. Undesirable additive must be overcome and the total additive formulation balanced to achieve optimum ance in the finished lubricant.

Often the solution to a lubricant formulation problem lies not in chanrring

Lubricant base stocks influence additive performance through two main functions; solu-

Additive formulation requires consideration of interaction and competition

Volume I t 309

concentration of an additive, but in changing the additives themselves. Molecular weight, molecular weight distribution, reaction conditions, purity, and many other variables influence these parameters. Small amounts of chemicals added during additive manufacture often induce large changes in additive‘interaction performance. These “additive additives” are considered highly proprietary by additive manufacturers.

ACKNOWLEDGMENT

The author expresses sincere appreciation to Roger Watson of Batavia, Illinois, who consulted on chemical accuracy, authored the appendix, and provided constructive sugges- tions for the other aspects of the chapter. Assistance received from many members of the Amoco Research Center, Naperville, Illinois, is also gratefully acknowledged.

APPENDIX: EXAMPLES OF LUBRICANT ADDITIVES

A description of representative additives follows. Some additives are relatively pure chemicals, for example, the zinc dithiophosphates. Many additives, however, are reaction products of industrial grade chemicals using reaction conditions to control the product quality and performance. In these cases, the complex mixture is not extensively separated and the structures shown represent the major component of a generic group. A vast literature describes dditive properties and preparation in more detail^.^.^.^.'^.^^

1. Metal Dialkyldithiophosphates (Metal Dialkyl Phosphorodithioates)

S S R-o\ H I 0 - R P M P/

/ \ / \ / \ R - 0 S S 0 - R

Variations - M is usually zinc but may also be molybdenum, tungsten, or other metals. i !!e R U groups are derived from primary and secondary alcohols and alkyl phenols and may be single or mixed.

Manufacture - Alcohols or alkyl phenols are reacted with P,S,, to form the dialkyl- dithiophosphoric acids. The zinc salts are made by reacting the acids with zinc oxide.

Application - Antiwear, anticorrosion, and antioxidant used almost universally in lubricants.

2. Tricresyl Phosphate

0

Q Manufacture - Mixed cresols (except ortho) reacted with phosphorous oxychloride.

- Wear inhibitor for synthetic oils and greases.

310 CRC Handbook of Lubrication

3. Sulfurized Fats, Olefins, Hydrocarbons

R I

CH"'\ I

CH /s I R

R-S,-R

S II

R-C-R

Variations - The R groups are residues from olefin polymers, petroleum stocks, un-

Manufacture - Selected fats and hydrocarbons are heated with sulfur, sometimes in the saturated fats, terminal olefins, and terpenes.

presence of an alkaline catalyst. Application - Antioxidants, antiwear, and antifriction are widely used in industrial

lubricants including cutting oils and gear oils. d

H

Manufacture - Nitrous acid on o-phenylene diamine. $ 7 P

Application - Inhibitor for sulfur corrosion of silver and copper in industrial lubricants. 3

5. 2-Alkyl-4-Mercapto-l,3,4-Thiadiazole

N-N

Variations - 2,4-bis (alkyldithio)-l,3,4-thiadiazoles. R is -octyl or -dodecyl. Manufacture - Hydrazine and carbon disulfide are condensed to form the dim-

thiadiazole, which is then coupled with tertiary mercaptan using hydrogen peroxide. Application - Inhibitors for sulfur corrosion of silver and copper; wear and oxi

inhibitors in industrial lubricants.

6. Metal Diakyldithiocarbamates

.t)"'] 'R

Variations - M may be any of a variety of metals, including zinc and molybde

Manufacture -Secondary amines are reacted with carbon disulfide and caustic

Application - Antioxidants and antifriction additives.

is C, to C,,,. x is a function of the metal valence.

The sodium dithiocarbamate is then reacted with the metal chloride.

Volume I1 311

7. 2,4-Ditertiarybutyl-p-Cresol (DBPC)

Variations - This is the most important member of a class called hindered phenols. Several variations are formed by coupling two phenolic groups through the ortho or para positions by methylene groups, sulfur, or nitrogen.

Manufacture -p-Cresol is ortho alkylated using aluminum alkyl catalyst. Application - Antioxidants widely used in many kinds of lubricants.

8. Phenothiazine

H I

Variations - Ring alkyl groups. Manufacture - Reaction of diphenylamine with sulfur. Application - Antioxidant in synthetic oils for jet engines and in greases.

9. Phenyl Alpha Naphthylamine (PAN)

Variations - Ring substitutions. Manufacture - 1 -Napthy1 amine heated with phenol. Applications - Antioxidants for greases and synthetic oils.

10. Dialkyldiphenylamine

H

Variations - R may be phenyl or alkyl derived from olefins. Manufacture - Aniline is heated with strong acid to yield diphenylamine which is then

Applications - Antioxidants for greases, mineral oils, and synthetic oils. alkylated with chlorobenzene or olefin polymers.

312 CRC Handbook of Lubrication

11. Phosphosulfurized Pinene

S :,s, I,

R-P P-R 'S'

<"I Variations - R is derived from either alpha or beta pinene or a turpentine mixture. d

Manufacture - Pinene is reacted with P4SI0. Application - Antioxidant and anticorrosion additives.

12. Dilauryl Selenide

C,, H,, -Se-C,, H,,

Manufacture - Lauryl chloride heated with dimethyl selenide. Application - Antioxidant for greases and synthetic oils.

< 13. Neutral and Basic Metal Sulfonates i

Yo Ob R-S-O--M-O-S-R

\O O*

R0

*O R-S-0-M-0-H

Variations - Sulfonates are one of the oldest lubricant additives to be used on a scale; they have evolved into a large Variety of similar materials. The R groups have from many different sources including by-products of lube oil refining by sulfuric treating, heavy ends of alkylbenzenes from laundry detergent manufacture, alkyl benzene and naphthalene with olefin polymers, and alkylation of benzene with chlorinated petroleum fractions. Many different metals are used, but the most important sodium and the alkaline earths, magnesium, calcium and barium (see also Overbused Sulfonates).

Manufacture - The alkyl aromatics are prepared as indicated above. Sulfonation i with gaseous SO, or oleum. The soaps are prepared by direct neutralization with th oxide or hydroxide, or by metathesis of the sodium sulfonate with a metal halide.

Application - Emulsifiers and rust inhibitors are widely used id industrial lubrican

14. Overbased Metal Sulfonates

Variations - For R, see Neutral and Basic Metal Sulfonates. x = 1 to 15. Occasiom the CO, group is partially replaced by a hydroxyl or another anion. y = 10 to 30. M is USU magnesium, calcium, or barium. A micellar structure is postulated.

Manufacture- Several overbasing processes are used. In one, metal is decomposed with water in the presence of a sulfonic acid. In other or neutral soap, together with a suspension of the metal oxide or hydroxl water, and a promoter such as ammonia or amine, is blown with carbon dioxide

Volume I1 313

Application - Detergents, alkaline agents, and rust inhibitors widely used in crankcase motor oils and marine cylinder oils.

15. Metal Alkylphenate Sulfides

A-M M-A

R R R R

Variations - Phenates are generally produced in the form of complex basic or overbased (see Overbased Metal Sulfonates) soaps of magnesium, calcium, or barium. A represents a weak acid anion other than phenate, such as hydroxyl or glycolate. x is generally from 1 to 2. The metal-free phenol sulfides are also produced. R is ordinarily in the range of C,

Manufacture - Alkylphenol is sulfurized with one of the sulfur chlorides or with sulfur and a base catalyst. The phenol sulfides are then reacted with the metal oxide or hydroxide in the presence of a promoter such as ethylene glycol. Overbasing may be accomplished by contacting with CO,.

Application - Phenates are widely used as detergents, antioxidants, and alkaline agents in crankcase motor oils and in marine cylinder oils. Metal-free phenol sulfides are used as antioxidants in industrial lubricants.

to c,2.

16. Metal Alkylsalicylates

c-0’ II 0

Variations - R is derived from olefin polymers of 300 to loo0 mol wt. M may be any

Manufacture - Alkylphenols are heated with carbon dioxide under pressure with alkaline

Application - Detergents and antioxidants mainly used for crankcase motor oils.

of a variety of metals, but usually calcium or barium.

catalyst. The alkysalicylic acid is then neutralized with metal oxide or hydroxide.

17. Alkenyl Polyamine Succinimides

Variations - R is alkenyl from olefin polymer, e.g., polybutene, mol wt is 500 to 2000, X = 1 to 4. Stoichiometry may be varied to yield 2 succinimides: 1 polyamine. Other types of Polyamines may be used.

Manufacture - Maleic anhydride is condensed with olefin polymers. The resulting &enyl succinic anhydrides and acids are then reacted with polyamines.

314 CRC Handbook of Lubrication

Applications - Dispersants are widely used in crankcase motor oil. The alkyl succinic anhydrides and acids are used as rust inhibitors.

18. Alkyl Hydroxyl Benzyl Polyamine

Variations - R is from an olefin polymer, e.g., polybutene, mol wt 500 to 2000. x is 2 to 5. Stoichiometry may be varied to yield 2 phenols: 1 amine or 2 amines: 1 phenol or oligomers.

Manufacture - Phenol is alkylated with olefin polymer then reacted with formaldehyde and polyamine.

Application - Dispersants are widely used in crankcase motor oils.

19. Polyamine Amide Imidazoline

Variations - R e is derived mainly from commeqial isostearic acid, but ma

Manufacture - Polyamine is condensed with carboxyllc acid. Application - Detergents and inhibitors are used in two-stroke cycle oils and i

from other carboxylic acids, e.g., naphthenic. Other polyamines may be used.

oils.

20. Esters of Polymetbacrylic Acid

Volume I t 315

Variations - Copolymers with butene-I. Mol wt vary from 1 ,OOO to 1 ,OOO,OOO. Manufacture - Polymerization of pure isobutylene or mixed butenes via Friedel Crafts

Application - Viscosity modifiers are tackiness agents. catalysts.

22. Alkylene Oxide Derivatives

Variations - A large variety of materials have been made by condensing akylene oxides, mainly ethylene oxide and propylene oxide on active hydrogen compounds such as alcohols, phenols, and amines. In the structure above, ethylene and propylene oxide are condensed singly, together, or blockwise where x and y may vary from 0 to 50 or more and A may be hydrogen or an alkyl or acyl group.

Manufacture - Active hydrogin compounds with a strong base catalyst are condensed with alkylene oxides under pressure in a single operation or sequentially to form block polymers.

Application - Dispersants, emulsifiers, demulsifiers, and ancillary rust inhibitors are used in a wide variety of lubricants.

REFERENCES

I . Lubricating Oil Additives. SRI International, Menlo Park, Calif., 1979. 2. Ramney, M. W., Lubricanr Additives, Noyes Data Corporation, Park Ridge, N. J., 1973. 3. Ramney, M. W., Lubricant Additives Recent Developmenfs. Noyes Data Corporation, Park Ridge, N. I.,

1978. 4. Ramney, M. W., Synthetic Oils and Aaiiitives for Lubricants: Advances Since 1977, Noyes Data Corpo-

ration, Park Ridge, N. J., 1980. 5 . Passut, C. A. pad Kdlmnn, R. E., Laboratory Techniques for Evaluation of Engine Oil Effects on Fuel

Economy, Paper Number 780601, Society of Automotive Engineers, Inc., Warrendale, Pennsylvania (1978). 6. Haviland, M. L. pad Goodwin, M. C., Fuel Economy Improvements with Friction Mod@ed Engine Oils

in Environmental Protection Agency and R w d Tests, Paper No. 790945. Society of Automotive Engineers, Warrendale, Pa.. 1979.

7. Davis, B. T . et ai., Fuel Economy ben@sfrom Modified Crankcase Lubricants, Paper presented at American Society of Lubrication Engineers, 34th Annual Meeting, St. h i s . Mo., 1979.

8 SAEHandbook 198l.SAE J183 preprint, Society of Automotive Engineers, Warrendale, Pa, February 1980. 9 SAE Hundbook 1979, Society of Automotive Engineers, Warrendale, Pa., 1979, 13.02.

10. ASTM Special Tech. Publ. 315G, Multicylinder Tesr Sequences for EvaIuating Automotive Engine Oils,

11. ASTM Special Tech. Publ. 315H. Part III, American Society of Testing and Materials, Philadelphia, in

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