JPS5915957B2 - lubricating oil composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to novel lubricating compositions containing critically defined block copolymers that impart high viscosity, viscosity index and detergent properties to the overall composition.

The lubricant is particularly useful in internal combustion engines, but is also useful in, for example, transmission fluids.
), can also be used for other related purposes such as in gear lubricants and others.

Lubricating oil formulation technology has become increasingly complex due to ever more stringent requirements created by advances in automotive technology.

One of the main demands is to produce an economical lubricant that can be used over a wide range of operating conditions, especially as far as temperature changes are concerned.

At the same time, the prepared lubricant should possess the ability to resist oxidizing forces during its use as well as during storage, and if possible also provide cleaning action and dispersibility.

Multi-grade lubricant
○ Many types of polymer additives are used as thickeners, viscosity index (Vl)
It was primarily used as an improver and pour point depressant.

A common limitation of virtually all of these is shear sensitivity.

Many of these polymers are relatively high molecular weight materials;
This is not unexpected since it is therefore susceptible to shear degradation.

On the other hand, relatively low molecular weight polymeric materials have, at least to date, been relatively unsuitable as glue thickeners and V-improvers in automotive engine lubricants, even if they have reasonably good shear stability. It is considered ineffective.

It is an object of the present invention to provide high viscosity index lubricating compositions with good cleaning action and dispersion properties.

The present invention utilizes large quantities of hydrocarbon lubricating oils and 0.1-10
wt% AB block copolymer (where A is 2
Butadiene is a polymeric block of isoprene with a number average molecular weight of 0,000 to ioo, oooQ, and B is monovinylpyridine, methacrylateryl, ethylene oxide, propylene oxide, with a number average molecular weight of 200 to 25,000. , acrylate or methacrylate polymer block, and the block copolymer is hydrogenated to saturation of at least 80% of the olefinic double bonds of block A). provide.

According to the invention, the block copolymers described in more detail below not only increase the viscosity of hydrocarbon oils but also increase their viscosity index and also provide good detergent and dispersion properties. discovered.

Furthermore, these properties are also stable to oxidation and shear.

A two-block copolymer (two
-brook copol ymer) can be prepared by anionic polymerization using lithium compounds, especially lithium alkyls, as initiators.

This type of polymerization is well described in the literature; for example, this technique is described in U.S. Pat.
No. 40, and No. 3465063.

Hydrogenated derivatives of these unsaturated diblock polymers also act as dispersants.

These diblock copolymers have sharply defined polymer blocks and usually have narrow molecular weight distributions.

These are essentially a single species. That is, they include homopolymers formed from unreacted starting polymers, such as copolymers prepared by grafting, grafted polymers with wide variations in molecular weight and composition, and "grafting monomers." It is not a mixture of various chemical species, including combinations.

In the production of these diblock polymers, a diene polymer block is usually made first and a second monomer block is added after the diene monomer has been used up by polymerization or the excess has been removed. mass is added.

Hydrogenation can be carried out subsequent to polymerization if desired.

The diene polymer blocks can be made from open chain conjugated dienes having from 4 to 8 carbon atoms per molecule, preferably from 4 to 6 carbon atoms per molecule.

Mixtures of dienes can also be used, still containing dienes and small amounts of
Mixtures with monoalkenyl arenes (such as styrene or alpha methylstyrene) can also be used to make this polymer block; typical conjugated dienes that can be used are butadiene, such as isoprene or , 3-dimethylbutadiene, methylpentadiene, and others.

Particularly preferred are butadiene and isoprene.

In the present invention, the microstructure of the diene polymer block (microstructure) using butadiene and isoprene is particularly important.
The structure can be controlled at will by, for example, controlling the polymerization environment.

Means for such control are known in the art.

For example, in the case of polyisoprene blocks, relatively high 1,4-capacity, in other words greater than about 80% 1,4-structure, and even more preferably even more than about 90% 1,4-
- It is advantageous to use one with a capacitance.

When hydrogenated under these conditions as described hereinafter, the resulting polymers exhibit excellent sensitivity to pour point depressants, good low temperature properties and thickening ability over a wide molecular weight range. These are block polymers having the following properties.

However, higher 3,4-capacity, i.e. 20-70
% polyisoprene blocks can be used as long as the average molecular weight is adjusted in its upward direction for this microstructural change.

When butadiene is the primary diene monomer used in the structure of the diene polymer block, at least about 30% .2- structure is preferable.

Good results are obtained when the 1,2-capacity of the polybutadiene block exceeds about 70%.

However, when such high 1,2-structures are used up, the number average molecular weight must be correspondingly increased in order to obtain sufficient glue consistency of the lubricant while still obtaining optimal low temperature properties. It must be.

Formation of the second polymer block in the diblock polymer is usually initiated by the active polygenyl metal first block.

Suitable monomers for the second polymer block are those monomers which can be polymerized by polygel metal, usually polygenyl lithium, and which polymerize to form the polar polymer block. It is the body.

Mono-alpha alkenyl arenes [comonomer (como
Many types of monomers are suitable for the second polymer block, such as monoalkenylpyridines, methacrylatelyls, alpha-oxidized olefins, and mixtures thereof. represents a monomer useful for the second polymer block, and one alkenyl group is attached to a ring carbon atom adjacent to or three carbon atoms away from the nitrogen atom of the pyridine ring. Contains alkenylpyridine monomers having the following.

The term monoalkenylpyridines still refers to the basic alkenyl pyridines, as well as those alkenylpyridines in which one or more rings are fused to the pyridine ring, such as 2-but also 4-vinylquinoline or tetrahydroquinoline. The pyridine unit is alkyl, aryl
), aralkyl, alkaryl (a
lkaryl), cycloalkyl, alkoxy, aryloxy (aryloxy) The term "alkenyl" includes the term "vinyl" herein.

Suitable monoalkenylpyridine monomers include 2-vinylpyridine, 2-methyl-4-vinylpyridine, 3,5-
Diethyl-4-vinylpyridine, 5-cyclohexyl-
2-vinylpyridine, 4-phenoxy-2-vinylpyridine and 4-dimethylamine-2-vinylpyridine.

Preferred monomers are 2-vinylpyridine or 4-vinylpyridine.

Methacrylnitrile is still a monomer that is mixed in to produce the second polymer block of the desired diblock copolymer.

These monomers have the general formula where R1 and R2 or both are hydrogen, alkyl, aryl or aralkyl.
yl) group.

Examples are metacyclonitrile, 3-methylacrylonitrile and 3-phenylmetacyclonitrile.

Metacyclonitrile is a preferred monomer.

Alpha-oxidized olefins are also suitable monomers from which to make the second polymer block.

These monomers have the general formula: where R3 is an alkyl or aryl group.

Typical oxides are ethylene oxide, propylene oxide, butylene oxide, styrene oxide and butadiene monooxide.

Ethylene oxide and propylene oxide are the preferred monomers.

In order to produce the second polymer block, in particular monovinylpyridine, metacyclonitrile, ethylene oxide, propylene oxide, acrylate or methacrylate are used in the invention.

In the diblock polymers of the invention, the number average molecular weight of the diene polymer block is from about 20,000 to about 100.
,000, but the preferred average molecular weight of the diene polymer block block is 40,000 before hydrogenation.
,000 to so,ooo.

Prior to hydrogenation, the second polymer block is about 200 to about 2
may have an average molecular weight of up to 5,000, but about 400
An average molecular weight of from about 10,000 is preferred.

The diene polymer block can constitute from about 10% to about 99% of the total weight of the diblock copolymer, but preferably the proportion will be from about 40% to 97% by weight.

The diblock polymers are prepared using an alkyllithium initiator in an inert solvent at temperatures of about -75°C to 75°C.

After polymerization of the diene polymer block, a second monomer is added to continue the polymerization.

It is often advantageous to cool the reaction mixture to a temperature well below 0° C. before adding the second monomer in order to minimize side reactions with the pyridine nitrogen or cyano groups.

When the polymerization of the second monomer is complete, the activity of the polymer is destroyed by methanol or acetone or HCI.

The resulting solution can be hydrogenated if so desired,
The unhydrogenated solution is still a non-solvent (non-5olv).
ent) or by stirring with steam and hot water.

The diene polymer block of the diblock copolymer is hydrogenated to improve the resistance to degradation of the unsaturated portions of the polymer.

Hydrogenation can also be used to reduce the basicity of pyridine nitrogen atoms by converting them to piperidine nitrogen atoms by hydrogenation.

An amino functional group can also be introduced by converting the nitrogen atom into an amine by hydrogenation.

Hydrogenation involves the addition of 35-
It can be carried out by reacting in the presence of a transition metal catalyst at 210 kg/i and 25-300°C.

Only the diene polymer blocks can be selectively hydrogenated to achieve improved oxygen and photoresistance.

At least 80% of the olefinic double bonds should be saturated.

The secondary
The polymer block may also be hydrogenated at the same time that hydrogen is being added to the diene polymer block.

For example, the polymer may be treated with a nickel catalyst at 40-50°C as a silvering agent containing pyridine rings.
When the hydrogenation was completed using Lewis acid as gent), only the butadiene polymer block of the butadiene-2-vinylpyridine diblock copolymer was saturated.

Under otherwise similar conditions at 170°C, butadiene polymer blocks and some 2- The vinylpyridine polymer block was hydrogenated.

A similar technique also hydrogenated the metacyclonitrile second polymer block by hydrogenating a portion of the nitrile groups to the amine groups in the presence of a nickel catalyst.

The presence of amine functionality in the second polymer block increases its polarity and basicity, and when utilized as a dispersant, this block polymer exhibits greater affinity for certain acid-type solids. become able to.

Similarly, biblock polymers having one diene polymer block and one second polymer block made from monoalpha alkenyl arenes are described in Canadian Patent No.
Selective hydrogenation was achieved using the technique described in 020720.

If desired both types of polymer blocks are 175-2
Hydrogenation can be carried out using the catalyst described in this patent at temperatures of 0.000C.

Although the oil component of the lubricating composition according to the invention can be formulated for the production of single grade lubricants, it is especially suitable for multigrade lubricants.
lti-grade) suitable for lubricants.

More specifically, the combination of block copolymers and pour point depressants according to the invention can be used, for example, in paraffinic crude oils,
It can be very advantageously incorporated into wax-containing lubricating oils from waxy crude oils such as naphthenic crude oils or mixed base crude oils.

Although lubricating oils of any value of viscosity can be used as a base for the present compositions, preferred oils are those known as high viscosity index neutral oils [e.g., HVI 100 neutral oil, H
VI 250 Neutral Oil and HVI Bright Stock (B
right 5tock) and mixtures thereof.

The number before “neutral oil” is 5aybol t Unive
This is an approximate viscosity value at 38°C in rsalSeconds.

Still, for example, various low viscosity index (LVI) oils and various very high high viscosity index (VHVI) oils produced by hydrocracking of inferior heavy oils can also be used.

More volatile oils may be used for special purposes, such as (HVI)8ON.

These neutral oils are produced by well known purification methods such as distillation, dewaxing, deasphalting, dearomatization, such as by solvent extraction.

The present invention is based, in part, on the discovery that only block polymers as defined above are effective as improvers in hydrocarbon lubricants having a viscosity index of at least 85, preferably at least 90. It was completed by

The following data shows that the block copolymers of the present invention have little or no effectiveness against ■ in low or moderate ■ oils, or yet substantially reduce ■ in such oils. Therefore, the criticality of the present invention will be understood in this respect.

Auxiliary additives can be used to provide the necessary stability, additional cleaning and dispersion, anti-wear and anti-corrosion properties currently required in lubricants.

Polymerized succinic acids used as detergent-dispersants, such as mono(polyisobutylene)succinic anhydride and succinimide of tetraethylenepentamine (the polyisobutylene group has a molecular weight of about i,ooo) Derivatives can be included among such auxiliary additives.

The most preferred ash-free dispersants are N
(B) at least one substituted polycarboxylic acyl containing an average of at least about 30 aliphatic carbon atoms per substituent such that there is at least one equivalent of polyhydric alcohol for each equivalent of substituted carboxylic acyl; an amount of at least one polyhydric alcohol to form an ester-containing initial reaction mixture;
This initial reaction mixture is then combined with about 0.02 of at least one hydroxyl-substituted primary amine per equivalent of (5) above.
5 to about 0.15 equivalents.

These reaction products and methods for their preparation are described by Widmer.
et al., U.S. Pat. No. 3,576,743 (19
Published on April 27, 1971).

More particularly, (5) is an ethylenically unsaturated carboxylic acid reactant Ro-(-C00H) of the formula:

or the corresponding halogenated carboxylic acids, anhydrides and esters, where R8 is characterized by the presence of at least one ethylenically unsaturated carbon-carbon covalent bond, and n is from 2 to 6. is an integer),
an ethylenically unsaturated or chlorinated hydrocarbon containing at least 30 aliphatic carbon atoms and a 100°-
a substantially saturated acylating agent prepared by reacting at a temperature within the range of 300° C., provided that the acylating agent has a polar substituent, such polar substituent being a carboxylic acid group; It is further characterized in that it can contain up to no more than 10% by weight of the hydrocarbon portion of the acylating agent, excluding weight.

Use of such detergents results in a substantial reduction in ash content (e.g., 15-50%) compared to the use of other otherwise effective and satisfactory detergents.

Basic alkaline earth metal petroleum sulfonates and alkaline earth metal alkyl carbonates (i.e. phenates)
and alkyl salicylates are also useful.

Furthermore, the metal alkyl dithiophosphates can be used as phosphonates such as P2S5-terpene reaction products, such as dibutylmethanephosphate and dibutyltrichloromethanephosphonate.
) such as triphenyl, tricresyl, trilauryl and tristiarylorthophosphate.
full esters of valent phosphorus acids
')% and dithiocarbamates (preferably zinc salts) as well as auxiliary additives.

Anti-foaming agents such as silicone polymers, such as dimethyl silicone polymers, can also be used.

When desired, oxidative stability and scuffing (s
Additional improvements regarding prevention of cuffing, e.g.
Examples of phenolic antioxidants such as alkylphenols include 2,6-ditert-butylphenol (2,6-ditert-butyl-4-methylphenol).
-4-methylphenol) or small amounts of P,P'-methylene bisphenols, such as e.g. This can be done to the filter oil composition of the present invention by mixing.

Anti-scuffing agents include metal salt esters of organic phosphites, phosphates, phosphonates and their thio derivatives, such as c3-18) realkyl phosphites or phosphonates, such as tributyl-, trioctyl-, trilauryl-, tristearyl-, Includes tricyclohexyl-, tribenzyl-, tricresyl-1 or triphenylphosphite or phosphate.

An example of a preferred composition according to the invention is shown.

Ingredients - Weight % Block copolymer 0.1 -10 Pour point depressant 0.1 -5 Oil-soluble metal thiophosphate 0.01-0.3 Ash-free detergent 0.1 -8.5 Overbase Sex (o
verbased) Alkaline Earth Metal Alkali Sulfonate 0.05-3.5 (Basic Sulfuric Acid Stock) Oil Residual Pour Point Depressant used in conjunction with block polymers as defined above according to the present invention Agents are primarily used for their pour point depressing effects, although many of them can act as viscosity index improvers or thickeners.

However, since they are used in small amounts (pour point depressing), e.g. 0.1-2.5% by weight, preferably 0.15-0.7% by weight, their proportion is normally too small to exceed the pour point. shows no substantial effect on oil properties.

However, the presence of a pour point depressant is necessary since the block copolymers defined above exhibit virtually no effective pour point depressant function.

On the other hand, one of the main properties of said block copolymers is their effectiveness in adding pour point depressants such as high molecular weight copolymers of alkyl acrylates or alkyl methacrylates as well as nitrogen-containing acrylic esters. This is a significant influence.

The term "acrylic esters" refers to esters of the acrylic acid family, including both acrylic acid and methacrylic acid.

The nitrogen-containing acrylic ester polymers described above can be prepared by any suitable means, such as those described in U.S. Pat. No. 3,215,632.

Examples of such polymers include vinylpyridine and cs-3o.
Examples include copolymers of alkyl acrylates.

Although the polar block copolymers of the present invention can be the only block polymers used in lubricants, they can also be used as supplementary improvers and dispersants in lubricants containing other improvers. can.

Diblock copolymers having the general structure poly(monoalkenyl arene) hydrogenated polydienes are important among these other improvers.

The most preferred types of these are polystyrene blocks in which the polystyrene blocks have an average molecular weight between about 10,000 and 55,000 and the hydrogenated polyisoprene blocks have an average molecular weight between about 20,000 and 100,000. It has a hydrogenated polyisoprene structure.

The following reference examples illustrate how polar polymers can be synthesized.

Reference Example 1 A butadiene-vinylpyridine diblock polymer is prepared and hydrogenated.

A certain amount of butadiene was introduced into dry cyclohexane.

Sec-butyllithium is then added to initiate polymerization;
Butadiene was then converted into a live polar molecule with an average molecular weight of approximately 50,000.

When butadiene is used up, 2-vinylpyridine
．． was added to the reaction system to produce a second polymer block having an average molecular weight of 1,000,000 and attached to each polybutadiene block.

The molecular weight was determined by the tritium analysis method and the nitrogen analysis of the product from the polymerization (5.2
(% by weight) was completely hydrogenated.

Prior to hydrogenation, the pyridine nitrogen atom is complexed with a molecular equivalent of boron trifluoride, followed by a nickel catalyst with 1
:500 catalyst to polymer weight ratio.

The catalyst was previously prepared by reacting nickel caprylate with 2.5 times its molecular weight of aluminum triethyl for 15 minutes at 25°C.

Hydrogen was then introduced to a pressure of about 84 kg/crIL.

The temperature was held at 40-50° C. for about 3 hours to reduce over 95% of the olefinic double bonds without substantially hydrogenating any of the vinylpyridine double bonds.

Reference Example 2-5 The binary block copolymer was prepared by converting butadiene (71 g) to the second
ether/butyllithium (1,47 mol)
Producing live polybutadiene blocks in toluene,
After cooling to -50°C, methacrylate trile (6,2
5g) was added to complete the production.

The copolymer was terminated in place by HCI.

The product was hydrogenated using a Ni/Al catalyst at ~40°C/49 to 70 kg/critH2 to reduce the butadiene block unsaturation.

The average molecular weights of the hydrogenated butadiene and polymetacyclonitrile polymer blocks were 50,000 and 1,500 as the isooctane-soluble portion (90% W) of the final product.

- The corresponding polymer 3-5 was synthesized using the same monomers by varying the block molecular weight and by hydrogenating the butadiene-acrylonitrile block polymer as follows.

Nickel acetylacetonate (n 1ckelace)
tylacetonate) with three times the molecular weight of aluminum triisobutyl (1:40 weight ratio to polymer).
This copolymer was prepared using 0) in isooctane solution.
Hydrogenation was carried out at 00° C. and nitrogen pressure from 52.5 to 84 kg/cIIL.

The polybutadiene block was fully saturated after ~4 hours, but the metacyclonitrile polymer block was only partially converted to the corresponding amine: nitrogen in the hydrogenated polymer. Approximately 20% of the atoms reacted basicly with hydrogen chloride in a non-aqueous solvent in potentiometric titration.

The data show that the reactive dust of the amine was created by hydrogenation.

The block molecular weights of these hydrogenated polymers are shown in the table below.

Reference Example 6 A diblock polymer was prepared from butadiene and ethylene oxide using preliminary techniques similar to those described in Reference Examples 1 and 2.

However, after the production of butadienyllithium and cupping with ethylene oxide (B
-C-C-OLi), requiring the addition of 1 mole of Ko-t-Bu per mole of butadienyllithium (B-Li) for the growth of polyethylene oxide blocks.

Ethylene oxide at a concentration of 18% W in benzene (
EO), 20% conversion of EO to 37° in 30 hours
was generated by the molecular ratio of I K :I Li at C.

Homopolyethylene oxide can be separated by coagulation in acetone and washing with acetone.

This butadiene/ethylene oxide block copolymer was hydrogenated in cyclohexane solution using a nickel catalyst at 40° C. to saturate 95% of the olefinic double bonds in the butadiene polymer block.

Reference Example 7 A block polymer containing sodium methacrylate units is
It was produced by hydrolysis of the hydrogenated butadiene-acrylonitrile polymer of Reference Example 3 in a mixed aqueous sodium hydroxide/tetrahydrofuran solution.

Reference Example 8 A diblock copolymer was prepared from isoprene and 2-vinylpyridine.

The average polymer block molecular weight is 50,000 and 55,
It was 000.

The copolymer was hydrogenated as a 10% solution in heptane using a nickel catalyst prepared by reacting nickel caprylate and aluminum (IJ ethyl).

Before the catalyst was introduced, 1 mole of boron trifluoride (as etherate) was added to prevent deactivation of the catalyst by complexing each mole of pyridine nitrogen atoms.

Hydrogenation was carried out at 40° C. and 70 kg/i hydrogen pressure.

After 5 hours of reaction, 95% of the olefinic double bonds in the polyisoprene block were saturated.

EXAMPLES Compositions containing polymers prepared as described in Reference Examples 1-7 were tested in a micro air oxidation test.

This test uses the following ingredients: HVI-Zoo neutral oil
30ffl antioxidant 0.2%
This was done by preparing a lubricating composition containing 5 drops of silicone antifoam fluid block copolymer (see table below).

The oil composition was added in the presence of 20 parts per million of copper and iron catalyst in an air flow of 4.2 liters per hour at 149°C.

Under these circumstances, the following data has been collected: First, the polymers are excellent thickeners, effective viscosity index improvers, and have a substantial effect on extending the useful life of the base oil. It is shown that.

262-

Claims (1)

[Claims] 1 Large amounts of hydrocarbon lubricating oil, and 0.1-10% by weight
A-B block copolymer (where A is 20.0
B is a polymeric block of butadiene or isoprene having a number average molecular weight of 00 to 100,000;
For example, a polymer block of monovinylpyridine, methacrylate tolyl, ethylene oxide, propylene oxide, acrylate or methacrylate having a number average molecular weight of 200 to 25,000; A lubricating oil composition comprising: hydrogenated until at least 80% of the heavy bonds are saturated.