JPS6128594A - Hydrogenated polyisoprene lubricant composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to compositions useful as lubricating oils having a gastric viscosity index, superior resistance to oxidative degradation, and resistance to viscosity loss caused by permanent or temporary shear.

According to the present invention, (high viscosity hydrogenated polyisoprene having a viscosity greater than 3500 and up to 175,000 centistokes at 100'C; (II) low viscosity synthetic hydrocarbons such as alkylated benzene or A lubricant composition is provided that includes a viscosity poly-alpha-olefin and/or a low viscosity ester, such as a monoester, diester, polyester, and optionally (iii) an additive package.

It is an object of the present invention to provide lubricating compositions with properties not available with conventional polymeric thickeners.

Yet another object of the present invention is to provide a lubricating composition that exhibits improved shear stability, good oxidative stability and good temperature-viscosity properties.

The viscosity-temperature relationship of lubricating oils is an important criterion that must be considered when selecting a lubricant for a particular application. Mineral oils commonly used as bases for single and multigrade lubricants exhibit relatively large changes in viscosity with changes in temperature. Fluids that exhibit such a relatively large change in viscosity with temperature are said to have a low viscosity index.

The viscosity index of Jintsu's paraffin mineral oil is approximately 100 II! ! Give Ev. Viscosity index (VI) HA, VIY40
"C and kinematic viscosity measured at 100°C by ASTM method D2770-74.

Lubricating oils consisting primarily of mineral oil are said to be single grade. According to the SAE rating, at high temperatures,
It is required to have a certain minimum viscosity 2, and to be multigrade it is required to have a certain maximum viscosity at low temperatures. For example, 10 c at 100°C
viscosity of st (hereinafter, unless otherwise specified, all viscosities are 1
00℃) is SAE 30.
and an oil with a viscosity of 3400 cP at -20'O would be rated 10W-30. 1
0C8t unmodified oil is 10W-30 multigrade grade.

The viscosity index of the 10W-30 multigrade grade cannot meet the low-temperature quality requirements of be.

The viscosity requirements for qualification as a multigrade engine oil are set forth in 8AE Engine Oil Viscosity Classification - 8AE J 300 BEP 80, effective April 1, 1982. The low temperature (W) viscosity required quality is determined by the cold cranking simulator (Co1d CrankingS).
imulator) fThe apparent viscosity of motor oil at low temperatures used is ASTYD2.
602 and results are reported in centipoise. Viscosity at relatively high temperatures (100°C) is determined by AST, a method for measuring the kinematic viscosity of transparent and opaque liquids.
M D 445 and the results are measured in centistokes (C8t).

The following table outlines the high and low temperature requirements for SAE grades approved for engine oil.

OW 3250-30”C 6.8
5W 3500-25℃ 6.81
0W 3500-20℃ 4.11
5W at 3500-15°C 5
．． 620W 4500-10℃
5.625W at 6000-s℃
9.620
5.6 Less than 9.3 30
9.3 Less than 12.5 40
12.5 Less than 16.3 50
16.3 21.
Similarly, 5AEJ 3 C16c describes the required quality of the viscosity of lubricants for axles and manual transmissions. High temperature (100°C) viscosity measurement is performed using ASTM
Do it by 445. The measurement of low temperature viscosity values is determined by the method of measuring the apparent viscosity χ at low temperatures using a Soltsk cold viscometer (ASTMI) 2983, and the results are reported in centipoise (cP). The relationship between 0(cP) and (C8t) is as follows.

The following table summarizes the lubricants for axles and manual transmissions and the required low-temperature quality Z.

70W -55 75W -404,1 80W -267,0 85W -1211,0 9013,524,0 140-24,041,0 From these tables there are a wide range of multigrades such as 5W-40 or 70W-140. The viscosity index of oil is 10
It is clear that it has a much higher viscosity index than narrow multigrade lubricants such as W-30. The required quality of the viscosity index of different types of multi-durage fluids can be roughly determined by the ASTM standard Liquid Petroleum Product Viscosity - Temperature Char (D341).

High temperature on D641 chart (40℃ and 10
If we assume that the extrapolation to -40°C or lower is a straight line, then for example 12.5 cst,
100”0 viscosity and -3500cp at 25°C
The line connecting the low temperature viscosity of

The 40°C viscosity, evaluated by a straight line connecting the 100°C and -25°C viscosity, would be about 70 cat.

K, -100=12.5 cst, and -V,
4o = 70 cat.

The viscosity index of the oil is about 180 (A8TM 22
70-74). 1 unless the viscosity of a certain fluid at 25°C is lower than the viscosity calculated from the linear relationship described.
At least 180 to qualify as 0W-40
It must have a viscosity index of

In fact, many VIY-improved oils include K, ■, 1o.

and has a viscosity at 25°0 of the sieve that is significantly lower than that predicted by linear extrapolation of V,,o.

Therefore, even an oil with a VIY of 180 does not guarantee that the blend is a 5W-40 oil.

This method can be used to evaluate minimum viscosity index requirements for various crankcase or ear oils. Some typical ratings are shown in the following table: 10W-309,360135 5W-4012,570180 5W-509,353159 Of-501<5.3 75.5 232 Ear Oil Grade 80W-14024270112 75W-14024200149 75W-2504131 8184 70W-14024150192 Therefore, it will be seen that very broadly multigrade lubricants such as 5W-40 or 75W-250 require thickeners to make the final blend very thick. .

In order to improve the viscosity index of mineral oils or low viscosity synthetic oils, polymeric thickeners have been added to relatively non-viscous base fluids.

Polymeric thickeners are commonly used in the production of multigrade lubricants. Typical polymers used as thickeners include hydrogenated styrene isoprene block copolymers, ethylene and propylene v-based rubbers (O
CP), filtrate polymers produced by the polymerization of high molecular weight esters of the acrylate series, polyisobutylene, and the like. These polymeric thickeners reduce the viscosity of the base fluid, t
It is added until the viscosity required for a given 8AE grade is achieved and the viscosity index of the fluid is improved to allow for the production of multigrade oils. Polymeric VI improvers traditionally have molecular weights between io, o o o and 1.00.
It is a rubber whose molecular weight varies between 0.0 and 0.00. Since thickening power and VI increase are related to the molecular weight of the VI improver, most of these polymers usually have at least 10
It has a molecular weight 2 of 0.000.

In the case of the production of multigrade lubricants, the use of these high molecular weight process improvers has some important drawbacks: (1) They are sensitive to oxidation, thereby losing VI and thickening power and often (11) They are susceptible to large viscosity losses due to mechanical shear when exposed to the high shear rates and stresses encountered in the crankcase or ears; (lii) These has Z, which is highly susceptible to temporary shear.

Transient shear is still a result of the non-Newtonian viscosity associated with molecular weight polymers. This is 91j under high judgment speed
This occurs due to the alignment of the polymer chains in the llilT field, resulting in a decrease in viscosity. This viscosity decrease is
Reduce Bw retention from wear associated with viscous oils. Newtonian fluids maintain their viscosity regardless of the shear velocity.

The inventors have developed a multigrade lubricant that is free of or significantly reduced in defects such as those found in polymer-thickened oils, which could not be achieved with prior art formulations. It has been discovered that it can be produced by a certain unique combination of fluids and additives.

A certain percentage blend of high viscosity hydrogenated polyisoprene (HPI), low viscosity synthetic hydrocarbons and/or low viscosity esters forms the base fluid, which by addition of the appropriate additive "package" Case oil or gear oil can be produced.

The finished oils thus produced are extremely commercially stable to permanent shear, and because of their near-Newtonian nature, temporary shear, if any, is small and therefore suitable for Maintains the viscosity required for wear protection. The oil stains of the present invention exhibit significantly better stability against oxidative degradation than prior art oils. The unexpectedly low viscosity index of our base fluid blend allows for the production of widely multigrade crankcase oils such as 5W-4o and gear oils such as 75W-14o. Until now, the production of such lubricants has been difficult, if not impossible, without the use of often harmful amounts of polymeric VI improvers.

The polyisoprene of the present invention can be produced by Ziegler-type polymerization or preferably by anionic polymerization. Such polymerization methods are described in US Pat. No. 4,060,492.

A preferred method for the production of liquid hydrogenated polyisoprene for purposes of the present invention is the anionic alkyllithium catalyzed polymerization of isoprene. A large body of literature regarding the use and methods of such catalysts is available to those skilled in the art. The use of an alkyllithium catalyst such as sec-butyllithium results in polyisoprene with a low 1,4-content (usually greater than 80%) which renders the main chain unsaturated.

When the alkyllithium catalyst is characterized by the addition of an ether or amine, a controlled amount of 1.2-
and 6.4 - Addition is performed.

1.4-Addition 1.2-Addition 6.4-Addition Hydrogenation of these structures gives the saturated compounds shown below.
-CH2-CHCH2 +I,
ICH2CH3 1,2-addition (B) CH2C
H3 6,4-addition (C) Structure (
A) is preferred due to its low Tg and low percentage of pendant groups (CHp-) in its body. Structure CB) is defective because it contains tetra-substituted carbon, which is a thermally unstable site. Structure (C) contains as much as 60% in its body of pendant (isozorobyl) groups which reduce the thickening power of repeating constant molecular weight oligomers and increase the Tg of the resulting polymer. This latter value has been shown to be related to the viscosity index. Optimization of structure (A) is desirable in order to obtain the best combination of thickening power, safety and VI improvement.

Another feature of alkyllithium polymers is that their molecular weight and molecular weight distribution can be easily controlled. Molecular weight is a linear function of the monomer:further ratio and can be very precisely controlled if careful attention is paid to the exclusion of impurities, ensuring good quality control of the production of such polymers. Alkyllithium catalysts can easily have a molecular weight distribution in an extremely narrow range, such as a MWAn ratio of 1.1. A narrow molecular weight distribution is highly desirable for v-process improvers because at a certain molecular weight thickening power is maximized while oxidative and sheer instability is minimized. If desired, wide or variable M, W distributions can be readily produced by methods well known in the art. Easily produced by the introduction of polyfunctional monomers such as star-shaped or branched polymers modibinylbenzene or by terminating the 1ving chain w1* with polyfunctional linkers such as dimethyl terephthalate. can.

It is well known that highly unsaturated polymers are significantly less resistant to oxidation than saturated polymers. Therefore,
It is extremely important to thoroughly reduce the unsaturation present in polyisoprene.

This can easily be done by anyone skilled in the art, e.g. for Pt, Pd or N1 in a pressurized hydrogen atmosphere at elevated temperature.
This method uses a catalyst.

Regardless of the method of manufacture, polyisoprene requires reduction of the high levels of unsaturation present after polymerization. K should saturate 90%, preferably 99% or more of the olefinic bonds for optimum oxidative stability.

The low viscosity synthetic hydrocarbons of the present invention having a viscosity of 7 from 1 to 10 cst consist primarily of oligomers of alpha-olefins and alkylated benzenes.

Low molecular weight oligomers of C8 (octene) to Cl2 (dodecene) or olefin mixtures can be used. Low viscosity α
-Olefin oligomers can be produced by Ziegler-catalyzed polymerization, thermal polymerization, free-radically catalyzed polymerization, and preferably BF, Y-catalyzed polymerization. A number of similar methods using BF3 in combination with cocatalysts are known in the literature. A typical polymerization method is described in U.S. Pat.
．． No. 045,508.

Alkylbenzenes can be used in the present invention alone or in blends containing heavy viscosity synthetic hydrocarbons and low viscosity esters with low viscosity poly-alpha-olefins. Alkylbenzenes produced by Friedelkraff alkylation of benzene with olefins are usually alkylbenzenes in which the alkyl chain is from 6 to 14 carbon atoms long. The alkylating olefins used in the production of alkyl, rubenzene are linear or branched olefins or combinations thereof. This material can be manufactured as shown in US Pat. No. 3,909,432.

The low viscosity esters of the present invention having a viscosity of 1 to 10 cst are, for example, monoesters prepared from monobasic acids such as pelargonic acid and alcohols, dibasic acids and alcohols, or diols and monobasic acids or acid mixtures. diesters prepared from and diols, triols (% trimethylolpropane), tetraols (like pentaerythritol), hexaols (like dipentaerythritol), etc. - reaction with basic acids or acid mixtures. The esters can be selected from a class of esters that are readily available commercially, such as the polyol esters produced by Polyol.

Examples of such esters include tridecyl pelargolate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, trimethylolpropane triheptanoate, and pentaerythritol tetrahezotanoate.

Instead of the synthetically produced esters mentioned above, there are esters and ester mixtures derived from natural sources of plants and animals. Examples of these substances are jo
joba nuts), Juzukiji, Pehana (saff
It is a fluid made up of pine kola whales) and pine kola whales.

The esters used in the inventor's blend should be carefully selected to ensure compatibility of all components in the finished lubricant of the present invention. Ester with a specific polarity (roughly its oxygen content is an indicator) 1. It should be noted that blending certain combinations of viscosity synthetic hydrocarbons and low viscosity synthetic hydrocarbons can cause phase separation at low temperatures, resulting in an apparent increase in viscosity. Phase separation is, of course,
It is not compatible with long-term storage of lubricants under various temperature conditions.

The additive "package" that is mixed with the base oil blend recommended for the production of multigrade crankcase fluids or ear oils is typically the best under the conditions of use that the specially formulated fluid will encounter. It is a combination of various chemical additives selected to work together.

Additives are classified as any substance that imparts or promotes desirable properties to the lubricating base blend in which they are incorporated. The general properties of the additive may be the same for various types or blends of lubricating bases, or the particular machining properties chosen will improve the time-saving phase and lubrication of the role in which the lubricant will be used. It will depend on the % mold of the base.

The main types of additives today are: tll dispersant, (2) oxidation and corrosion inhibitors; (31 wear resistance, purity additives, (4) viscosity improver, (5) Pour point depressant, (6) antirust compound, and (7) Foam inhibitor It is.

Typically, a complete lubricant will contain some, most or all of the above additives in an additive commonly referred to as an "additive package". With the development of balanced additive packages, each of the additives contains significantly more activity than was used on a whim. Under actual conditions of use, functional impairment is quite noticeable from the combination of these substances. On the contrary, unexpected synergistic effects of one desirable property are also becoming clear. The only methods currently available to obtain such data are experimental demonstrations and extensive full-scale testing in the field. Such testing is tedious and time consuming.

Dispersants have been described in the literature as "rffcs agents." Since their function is to disperse particulate matter rather than to "scavenge" any dust or debris present, it seems appropriate to place them in the class of dispersants. The material in this ridge is generally a large hydrocarbon [tail J
(tail) and a polar group head and 7. This tail, which is a lipophilic group, serves to solubilize it into the plugging fluid, and the impulse group serves as an adhesion element to particulate contaminants in the lubricant.

Dispersants include metal types and ashless types. Metal-type dispersants include sulfonates (neutralization products of metal bases and sulfonic acids), thiophosphonates (acidic components derived from the reaction of polydetenes with phosphorous pentasulfide), and phenate and phenol sulfide salts (alkylphenols, A broad class of phenates is included, including salts of alkylphenol sulfides and alkylphenol aldehyde products.

Ashless dispersants fall into two broad categories: high molecular weight polymeric dispersants for multigrade oil distribution and low molecular weight additives used where viscosity enhancement Z is not required. Compounds useful for this purpose are also characterized by having a "polar" group attached to a relatively high molecular weight hydrocarbon chain. This "polar J group contains - generally one or more of the elements - mononitrogen, oxygen and phosphorus. The solubilizing chains are generally of higher molecular weight than those used in metal-type dispersants, , in some instances these are one and the same thing. Some examples include N-substituted long chain alkenyl succinimides 1, products formed by esterification of mono- or polyhydric aliphatic alcohols with olefin-substituted co-hydric acids. These include high molecular weight esters such as Mannitz bases from high molecular weight alkylated phenols.

The sieve pre-electrobotomer ashless dispersant has the general formula = (wherein - oil extractable group = polar group R = hydrogen or alkyl group).

The function of antioxidants is to prevent the decomposition associated with the action of oxygen on lubricating base fluids. These inhibitors are free radicals (
It functions either by breaking the chain (chain breaking) or by interacting with the peroxides involved in the oxidation mechanism. Among the widely used antioxidants are e.g.
-butyl-p-bresol and phenolic types (chain-cleavage) such as 4,4'-methylenebis (2°6-di-tert-butylphenol) and zinc dithiophosphate (peroxide-decomposition).

Wear is the loss of metal and the associated clearance Yf between relatively moving surfaces which, if continued for 6 degrees, will cause malfunction of the engine or ear. Among the major factors causing wear are metal-to-metal contact, the presence of abrasive particulate matter, and corrosive acid attack.

Metal-metal contact can be prevented by the addition of film-forming compounds that protect the surface either by physical layering or chemical action. Zinc dithiophosphate is widely used for this purpose.

These compounds were listed under antioxidants and bearing corrosion inhibitors. Other useful additives include phosphorus, sulfur or combinations of these elements.

azorecipe wear (abrasive wear)
Although it can be effectively prevented by removing particulate matter through filtration,
Corrosive wear due to acidic substances can be prevented by the use of alkaline additives such as basic phenates and sulfonates.

Conventional viscosity improvers are also often used in the "additive package," but the specific blend of high and low molecular weight lubricating base materials of this invention exhibits the same effect and is therefore not used in the practice of this invention. These t are not necessarily required. However, the inventors do not intend to exclude the possibility of adding some amount of conventional viscosity improvers. These materials are typically oil-soluble organic polymers with molecular weights ranging from about 10.0 ODD to 1,000,000. The polymer in solution is swollen by the lubricant. This swollen mass determines the extent to which the polymer increases its viscosity.

Pour point depressants prevent oil from coagulating at low temperatures. This phenomenon is associated with the crystallization of wax from the lubricant.

The chemical structure of typical commercially available pour point depressants is: H It is.

Chemicals used as rust inhibitors include sulfonates, alkenylcophosphates, substituted imidacillins, amines and amine phosphates.

“-Foam suppressants include silicones and various organic copolymers.

Additive packages known to fulfill their recommended purpose are manufactured and sold by several major manufacturers. The proportions and types of additives used in each application are recommended by the supplier.

Typical packages available are: (+) Hytic () (ITECX Trademark) E-,
20 Automotive Gear Aburawa, (II) Lubrizol A/ (Lubrizol)
(Trademark) 5002 for industrial gear oil, (ill) Lusol 4856 gasoline crankcase oil, and Gy) OLOA (trademark) for 8717 diesel crankcase oil.

A typical additive package for automotive gear lubricants usually contains oxidation/inhibitors, corrosion inhibitors, antiwear additives, rust inhibitors, antifoam agents, and foam suppressants.

A typical additive package for crankcase lubricants is
Usually consists of dispersants, antioxidants, anti-corrosion, anti-wear, anti-corrosion agents, anti-rust agents and foam inhibitors.

Additive packages useful for compressor fluid distribution typically include antioxidants, antiwear additives, rust inhibitors, and foam suppressants.

In the present invention, high viscosity hydrogenated polyimrene (HP) having a viscosity in the range of 3500 to 175,000 cSt and one or more synthetic hydrocarbons having a viscosity in the range of 1 to 10 QSA and ( or) 1 camphor or more, 1-10. A blend with a compatible ester fluid having a viscosity in the cSt range is used.

Such blends, when treated with appropriately selected additives 'Package J', have improved tensile stability, improved oxidative stability, and are widely multifunctional with viscosity properties close to Newtonian liquids. It can be formulated as a grade or rank case or gear oil.The blends of the present invention can also be used in certain applications where the use of additives is not required.

Continuing part of the base oil blend, it is convenient to standardize the ratio of liquid high viscosity synthetic hydrocarbon, low viscosity synthetic hydrocarbon and low viscosity in the final lubricant to a total of 100%. The actual proportions used in the final formulation will be reduced by the amount of additive package used.

The HP engineered low viscosity synthetic hydrocarbon and low viscosity ester components are necessary for the present invention. The high viscosity liquid hydrogenated polyin prene provides thickening and V1 enhancement to the base oil blend. The examples demonstrate the improvement in VI produced by HP engineering during blending with low viscosity hydrocarbons or low viscosity esters.

Low viscosity synthetic hydrocarbon fluids are often a major component of base oil blends, especially when the finished oil lubricant is SAE viscosity grade 30 or 40. Certain low viscosity esters are insoluble in high viscosity synthetic hydrocarbons, but the presence of low viscosity synthetic hydrocarbons, which are good solvents for low viscosity esters, makes them highly viscous synthetic hydrocarbons, low viscosity synthetic hydrocarbons and Relatively variable esters can be used in the viscosity ester base oil blend.

Crankcase and gear oils composed solely of HP and low viscosity synthetic hydrocarbons and appropriate additives result in synthetic fluids with excellent oxidative and hydrolytic stability.

Low viscosity esters can be used in combination with HP engineering and low viscosity hydrocarbons, or with HP engineering alone. In ternary Prene P, proper selection of esters and hydrogenated polyisoprene oligomers results in crankcase and gear oil formulations with excellent viscosity index and low temperature properties.

A two-component blend of HP and ester can produce multigrade lubricants with excellent viscosity properties, detergency and oxidation stability. While there are some applications where high humidity environments exist which can be detrimental to certain esters, hydrogenated polyylene oligomer-ester blends may be advantageous for use in applications such as automotive gear oils with high ester content. It is.

If the use of a low viscosity ester as part of the blend is deemed advantageous, the low viscosity hydrocarbon acts as a common solvent for the HP process and additive ester. Depending on the polarity of the ester, the latter two components may be somewhat incompatible. Excellent multi-grade lubricants can be formulated with or without esters.

A third component, a low viscosity ester, can be added to the production of the superior lubricants of this invention. Multigrade lubricants can be made using only R1 and low viscosity synthetic hydrocarbons. Addition of low viscosity esters at low levels, usually from 1 to 25%, provides base oil blends with better cold flow properties than blends of high viscosity synthetic hydrocarbons and low viscosity synthetic hydrocarbons alone.

Low viscosity esters are typically 10-25% of synthetic base oil blends.
%, and more or less can be used in particular formulations.

If the end use is likely to be exposed to moisture, it may be advantageous to eliminate or reduce the amount of ester in the blend.

The components of the finished lubricant of this invention can be mixed in any convenient manner or order.

Important features of the present invention are that by using a properly structured base oil blend in combination with a suitably compatible additive package: (:) improved transient shear stability; (11) superior oxidation; Stability (+i+) The final wide range of multi-grade lubricants with high viscosity index can be produced.

The ratio range of each component, i.e. high viscosity hydrogenated polyimprene, low viscosity synthetic hydrocarbon, low viscosity ester and additive package, will vary widely depending on the end use application in which the formulated lubricant will be used. However, an advantage of the compositions of the present invention is that the base oil blend of high viscosity hydrogenated polyisoprene, low viscosity synthetic hydrocarbon and/or low viscosity ester is (standardized); 1-99% HPI, 1-99 % low viscosity synthetic hydrocarbons,
Blends of esters or mixtures thereof, from 1° to 80% HP and correspondingly from 90 to 20% of at least one low viscosity ester-based fluid or hydrocarbon-based fluid are preferred. Additive package is 0-2 of all formulations
Used at 5%, obtained when containing.

The lubricant of the present invention approaches the viscosity properties of a Newtonian fluid. i.e., its viscosity changes little over a wide range of shear rates.Although the IFI of the present invention itself exhibits non-Newtonian properties, especially at low temperatures, The product is close to Newtonian fluid.

The non-Newtonian properties of currently used V-finishing improvers are:
It is well explained in the literature. An excellent essay is ``Relationship between engine oil viscosity and engine performance...Part J (
The relationship between engi
ne”oil viscosity and engineering
810 publication under the title ne performance-Part ■). Text in this publication was presented at the 1978 SAE Convention and Exhibition, held in Detroit, February 27-March 3, 1978.

Interesting literature is paper 780574: "Temporary viscosity loss and its relationship to journal bearing performance J
(Temporary Viscosity 1os
s and 1tsrelaliozLship to
johrnal bearing performance
General Motors Research Institute, M.
This is an article by L. McMillan and O. Murp, hy.

This article and many others known to researchers in this field describe how all of the commercially available polymeric V-engineering improvers with molecular weights of 30,000 and above were subjected to shear rates of 105-106/sec. Explains whether it exhibits temporary viscosity loss. As the molecular weight of the polymer increases, the temporary viscosity loss in any shear increases accordingly. For example, 32,000.157.000 and 275.00
An oil thickened with polymethacrylate having a molecular weight of 0 is
The viscosity loss rate at a shear rate of 5×10 5 /s shows 10.22 and 62%, respectively.

The shearing speed generated in the piston and gear (106/
The loss of hydrodynamic film causes the oil's apparent viscosity to approach that of the unthickened base fluid, depending on the polymeric thickener used. Since the wear resistance of moving parts is correlated to the viscosity of the oil, it is clear that the wear resistance properties of lubricants degrade as a result of temporary shear. The near-Newtonian fluid of the present invention: maintains its viscosity even under these conditions of use, thus better protecting the mechanical parts to be lubricated and ensuring a long service life.

Currently used polymeric thickeners that exhibit temporary shear (recovery tendon) also undergo permanent shear.

Prolonged use of polymeric thickeners causes mechanical decomposition, resulting in loss of thickening power and reduced V-modulus. This is illustrated in Example 5. W, Wunderritsuhi (Wun
``Stability of Polymers in Engines'' by John Derlich and H. Jost (Rost)
In article 780372 (in the said publication) entitled ``Thility in Engines'', the relationship between polymer type and permanent shear is discussed. The multigrade lubricants of the present invention are less susceptible to mechanical shear.

The same paper also acknowledges an often overlooked feature of high molecular weight process improvers, namely their oxidative instability. Just as these polymers lose their viscosity due to cutting, they are also easily decomposed by oxygen, resulting in destruction of the polymer and a concomitant decrease in the viscosity index. The lubricating fluids of the present invention experience much less loss of viscosity index due to oxidation.

As mentioned above, the lubricant of the invention exhibits low temporary shear but guarantees an optimum viscosity for the protection of moving parts encountering high shear rates.

The importance of this feature is widely acknowledged. In the past, the S rating (e.g. sAx 30) was used to measure the viscosity of a fluid at 100°C under low shear conditions, even though mechanical parts such as the crankcase encounter high temperatures and very high shear rates. depended only on Because of this irrationality, in Europe the viscosity for certain grades is 150°C.
The new 17 rating system, which measures at a shear rate of 106/sec, has been adopted. This relatively realistic attempt has recently been considered in the United States as well. The advantages of incorporating Newtonian fluids into such a grading scheme will be apparent to those skilled in the art. The viscosity of Newtonian fluids can be directly extrapolated to 150° C. under high shear conditions. However, polymer-thickened fluids always have a viscosity lower than that extrapolated value, often approaching that of the base fluid itself. Under high shear conditions, polymer thickened oils will require a more viscous base fluid to reach certain grades.

Using a higher viscosity base fluid would result in a relatively high viscosity at low temperatures, but still pass the low temperature requirements of a wide range of multi-grade oils (5W for crankcases or 75W for gear oils). It will be even more difficult.

In other words, current polymeric Hv improvers do not perform realistic high-temperature, high-shear measurements for V-factor measurements [falsely improving J viscosity]. Become. The viscosity index has been determined by low shear rate measurements at 40" O and 100°C. The near-Newtonian fluid lubricants of the present invention are:
Multi-gray P with a high viscosity index that stays within 'greige'
This V-gear and multigrade rating is practical because not only do they produce fluids of 100%, but they are also less sensitive to shear.

Although the specific compositions illustrated in this specification are accurate, it will be apparent to those skilled in the art that valuable lubricant combinations may be made within the scope of this invention.

, Example 1 This example demonstrates the production of a crankcase lubricant using a HP process having the kinematic viscosity shown below.

A HP engineering (KVloo = 40ri0)
-9PAO-4"' 5
3di-2-ethylhexylazedi) 20
Lubrizol 3940 (2118 E HP Engineering (KVxoo = 28,350)
6PAO-456 Di-2-edylhexylazedi) 20 Luderizol 3940 180
HP engineering (KVloo = 106*100)
5PAO-457 Di-2-ethylhexyl azelate 20 This so-called? # agent is KVl(10,C8t KN'40.C8t VI
(!O8, QP SADguL
F-■■-floor-Lee--■-騨-■■-drunk■-Yo--
--■■1-A---■■--Acupuncture-11111A
13,4 77.6 1772465-20'(r l
0W-40B 10.0 54.3 1842.9
40-60° 0W-30014,178,3186
It had the characteristics of 2610-25TX 5W-40.

(1) 4 cst poly-α-olefin (2)
Additive pancake of Lubrizol company values.

Example 2 This example describes the production of a lubricant using a blend of only HPI and synthetic hydrocarbons having the following kinematic viscosities:

A HPI(xvlo(,=4030)
9PAO-479 Luprizole 4856 ”ゝ 12
B HPI (KVxoo = 28.350)
6PAO-482 Lubrizol 4856 12 Automotive gear oil OHPI (28,350) 13
PAO-477 Underground Mall 6043"' 10
This lubricant is AI3.6 81.6171 3485-2
At 5″C 5W-40B 13.7 80.3
1753315 - 5w at 25℃ - 40025,216
4,018847, 75W-140 at 300-40℃
It had the following characteristics.

(1) Additive package manufactured by Lubrizol.

EXAMPLE 6 This example demonstrates the construction of a crankcase lubricant using a blend of HPI and ester and additive package having the kinematic viscosities shown below.

Ingredients WT
%A HPI (KVloo = 4030)
9diynezodyladipate 79-Lubrizol 4856 12B
HPI (Iffloo = 28.350)
-7 Diisodecyl Adipate 81 Lupri Door 4856 12 This lubricant is: AI3.4 69.1 200 2245-3
Cfcc 0w74OB 164 65.3
212 The characteristics of 0W-40 were improved to 4 at 2180-30'C.

Example 4 This example demonstrates the production of an automotive gear oil detergent using HPI with the kinematic viscosity shown below.

Ingredients WT
%AHP engineering (Kv, oO=28,650) 9PAO-4
61 Di-2-ethylhexyl azelate 20 angramol 6043 10B HPI (KV
loo "" 28+350), 1
3PAO-45'7 Di-2-ethylhexyl azelate 20 Anglamol 6043 10 This lubricant is

Claims (2)

[Claims] (1) (A) a hydrogenated polyisoprene having a viscosity of greater than 3500 centistokes up to 175,000 centistokes at 100°C, and (B) 100 centistokes;
A lubricating composition characterized in that it comprises a mixture of synthetic hydrocarbons, esters or sores having a viscosity of from 1 to 10 centistokes at <0>C. (2) Addition of at least one member selected from the group consisting essentially of dispersants, antioxidants, corrosion inhibitors, anti-wear additives, pour point depressants, rust preventives, foam inhibitors and extreme pressure agents. The lubricating composition of claim 1 further comprising an additive package containing an additive.