JPS6088094A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To provide a lubricating oil compsn. which has excellent low-temperature flow characteristics and lubricating properties and gives little damage to sealing materials, by blending a polyether compd. having a specified structure with a synthetic lubricating oil other than polyether compd. in a specified ratio. CONSTITUTION:A lubricating oil compsn. contains a polyether compd. (A) of formula I or II (wherein R<1> is a residue of a 6-20C branched alcohol having a solidifying point of 0 deg.C or below; R<2> is H, a 1-28C hydrocarbon group; A is 3 or 4C alkylene; n is 3-40) and a synthetic lubricating oil (B) (e.g. a 4-16C alpha-olefin oligomer) other than polyether which is dissolved in component A at -20 deg.C to form a clear soln. in a weight ratio of A to B of 1:1-1:19. By combining components A and B in a specified ratio, a compsn, can be obtd. which has excellent low-temperature flow characteristics, low-temperature stability and lubricating properties, gives little damage to sealing materials, has excellent compatibility with additives and can be widly used at low temp.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a lubricating oil composition having excellent low-temperature properties and lubricity.

[Prior art]

In recent years, with the development of refrigeration equipment and the increase in the use of equipment in low-temperature regions, there has been a demand for lubricating oils with pour points of 120'C or less in order to improve the low-temperature startability of equipment. -2
Synthetic lubricating oils such as polyether oils, olefin polymerized oils, ester oils, and silicone oils are lubricating oil bases that exhibit pour points below 0°C, but although these bases exhibit excellent low-temperature properties, they are not widely used. Its use is limited because it has various disadvantages compared to the mineral oils used.

For example, polyether oil has excellent low temperature properties, viscosity properties, and lubricating properties, and has little effect on metals and sealants, but it is compatible with lubricant additives such as detergent dispersants, as well as mineral oil and olefin polymer oil. There are bad drawbacks.

Among olefin polymerized oils, α-olefin oligomer oil has properties similar to mineral oil and is a lubricating oil base with excellent low-temperature properties, but it has a large effect on sealants, and the effect of lubricating oil additives. There are drawbacks such as difficulty in achieving the desired effect and the need to add a large amount of additives. Among ester oils, dibasic acid esters exhibit very excellent low-temperature properties, but they have a large effect on sealants, and their low viscosity causes severe wear under conditions of use under high loads, making them unusable. There are drawbacks.

In order to eliminate the drawbacks of the respective lubricating oil bases as described above, attempts have been made to blend two types of bases, and an example of this is the blending of an α-olefin oligomer oil and a dibasic acid ester oil. This formulation system has better properties than when both bases are used alone, but because it is necessary to incorporate a large amount of dibasic acid ester to improve low-temperature properties, it tends to cause the sealant to swell. There was a problem with poor lubricity under high loads. On the other hand, a composition of polyoxyalkylene glycol monoalkyl ether and synthetic lubricating oil is used as an engine oil (Japanese Patent Application Laid-Open No. 159411/1983), but this also has poor low temperature characteristics.
It could not be used as a lubricant in low-temperature regions.

[Purpose of the invention]

The present invention aims to solve the above-mentioned conventional drawbacks, and by blending a polyether compound with a specific structure and a synthetic lubricating oil other than polyether compounds in a specific ratio, low-temperature fluidity can be improved. Another object of the present invention is to provide a lubricating oil composition that has excellent lubricity and has little effect on sealants.

[Structure of the invention]

The present invention comprises a polyether compound represented by the following formula [1) or (II) as the A component, and the above A as the B component.
This is a lubricating oil composition characterized in that it contains a synthetic lubricating oil other than polyether that is transparently soluble at -20''C in a weight ratio of 1:1 to 1:19.

R10(AO)nR” (1) (R”0(AO)n) 2 CH2(n) (where,
R1 is a residue of a branched alcohol having 6 to 28 carbon atoms and whose freezing point is 0°C or lower, R2 is hydrogen or a hydrocarbon group having 1 to 28 carbon atoms, A is an alkylene group having 3 or 4 carbon atoms, and n is the number of carbon atoms. The average number of moles of 3 or 4 alkylene oxides added is 3 to 40. ) In the compound of formula (1) or formula [II] which is component A, the alcohol having R1 as a residue is a branched alcohol having 6 to 28 carbon atoms, for example, obtained from an olefin or a low polymer thereof by the oxo method. alcohol,
These alcohols, alcohols obtained by the Guerbet reaction of linear alcohols, and natural branched alcohols contained in wool fat, etc., and not only primary alcohols but also secondary alcohols can be used. Examples of the above-mentioned branched alcohols include isohexanol, isoheptatool, 2-ethylhexanol, isooctatotool,
Isononanol, isodecanol, isoundecanol, isododecanol, isotridecanol, isotetradecanol, isopentadecanol, isohexadecanol, isoheptadecanol, isooctadecanol,
Examples include isononadecanol, isoeicosanol, isoheneeicosanol, isodocosanol, isotoricosanol, and isotetracosanol.

The reason why R1 is limited to branched alcohol residues is that R1
This is because if it is a residue of a linear alcohol, the solidification point of the polyether compound will be high, and when it is blended with component B, it will become cloudy or separate at low temperatures, making it impossible to use it as a lubricating oil for low temperatures. The reason why the number of carbon atoms in the branched alcohol is limited to 6 to 28 is because if it is less than 6, it has poor compatibility with additives and other synthetic lubricating oils.

The oxyalkylene group represented by (A○) in formula CI) or [R1 includes oxypropylene group, oxybutylene group, oxytetramethylene group, etc. These include propylene oxide, butylene oxide, tetrahydrofuran, etc. Indicates that it is an adduct of 3 or 4 alkylene oxides. These alkylene oxides may be added alone or in a mixed state,
In the case of a mixed state, it may be a random shape or a block shape.

The reason why the number of carbon atoms in the alkylene oxide is limited to 3 or 4 is that when ethylene oxide with 2 carbon atoms is added, the freezing point of the polyether compound increases and
This is because the compatibility with other components deteriorates, and when the number of carbon atoms is 5 or more, the effect on the sealing material is large, and in either case, it cannot be used as a lubricating oil for low temperatures.

Furthermore, the average number of added moles of alkylene oxide having 3 or 4 carbon atoms is limited to a range of 3 to 40 because if the average number of added moles of alkylene oxide is less than 3 moles, the viscosity of the polyether compound is low and the lubricating oil If alkylene oxide is used as a sealant, the lubricity deteriorates and phenomena such as abrasion are likely to occur, and the effect on the sealant is not improved.Additionally, if more than 40 moles of alkylene oxide is added, it will cause a problem with component B. This is because the compatibility deteriorates and the solubility of additives decreases, making it impossible to expect the effect as a lubricating oil.

In the polyether compound represented by formula (1), R2 represents hydrogen or a hydrocarbon having 1 to 28 carbon atoms, and an example of this hydrocarbon group is a methyl group.

Ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group.

Decyl group, undecyl group, dodecyl group, tridecyl group,
Examples include a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an eicosyl group, and they may be linear or branched. From the point of view of compatibility with component B and solubility of additives, R2
A hydrocarbon group having 1 to 28 carbon atoms is preferable.

The polyether compound represented by formula (11) or (II) is prepared by adding an alkali metal compound as a catalyst to the branched alcohol having R1 as a residue, and adding 1
A method of addition-polymerizing alkylene oxide such as propylene oxide or butylene oxide at a reaction temperature of 00 to 150'C, and in some cases, after addition-polymerizing the alkylene oxide and converting the crude reaction product into an alcoholade with metal sulfur, etc. It can be produced by a method of reacting an alkyl halide having 1 to 28 carbon atoms or methane dihalide.

Synthetic lubricating oils other than polyether, which is component B, include olefin polymerized oil, ester oil, alkylbenzene oil, l
There are R-acid ester oils, silicate ester oils, etc., and these synthetic lubricating oils must be transparently soluble in component A at -20°C from the viewpoint of low-temperature properties. These components are also necessary to improve the compatibility of various additives in low-temperature lubricating oils at low temperatures. In order to improve the compatibility of various additives at low temperatures, olefin polymerized oils or ester oils are preferred among these synthetic lubricating oils, and it is particularly desirable to blend olefin polymerized oils and ester oils together.

The olefin polymerized oil used here is preferably an α-olefin oligomer oil, and preferably an oligomer obtained by polymerizing 2 to 30 moles of an olefin having 4 to 16 carbon atoms, particularly isobutyne or 1-decene.

The ester oil may be monoesters, diesters, or polyol esters as long as it has a viscosity suitable for lubricating oil and a pour point of 120°C or lower, but from the viewpoint of low-temperature fluidity, two types are particularly preferred. Basic acid esters are preferred.

Preferred ester oils include di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate, diisodecyl adipate, diisodecyl sebacate, di-2-ethylhexyltetrahydrophthalate, diisodecyltetrahydrophthalate, Trimethylolpropane tricaprylate
Examples include trimethylolpropane trioleate l-.

The phosphoric acid ester oil may similarly have a pour point of 120° C. or lower, but tricresyl phosphate is particularly preferred.

The lubricating oil composition of the present invention comprises one or more polyether compounds represented by the formula (I) or (II) as the component A, and one or more of the other synthetic lubricating oils as the component B.
It is a composition containing "one or more species" in a weight ratio of 1:1 to 1:19, and each component may be simply blended. The reason why the blending ratio of both components is limited is that if the blending ratio of component A is smaller than the above range, the excellent properties of polyethers, such as low-temperature fluidity, lubricity, and reduced influence on sealants, cannot be sufficiently achieved. If the above range is exceeded, the solubility of various lubricating oil additives at low temperatures may decrease and cloudiness or precipitation may occur over time, resulting in insufficient performance as a lubricating oil for low temperatures. This is because they will no longer perform well.

When the lubricating oil composition is required to have low-temperature properties at temperatures below 140°C, 10 to 40% by weight of a polyether compound represented by formula CI) or formula (11) is added as component A;
Preferably, the components include 20 to 60% by weight of ester oil and 10 to 60% by weight of olefin polymerized oil.

The lubricating oil composition of the present invention may contain other components in addition to the above-mentioned A and B components, and if necessary, antioxidants, extreme pressure agents, detergent dispersants, antifoaming agents, etc. may be added. be able to. The lubricating oil composition of the present invention is suitable as a lubricating oil used at low temperatures, and is particularly suitable as a hydraulic oil, gear oil, and bearing oil for various machines used at low temperatures. In some cases, it can also be used as an engine oil with excellent low-temperature startability. Of course, it is not limited to use only at low temperatures.

〔Effect of the invention〕

According to the present invention, since a polyether compound having a specific structure and a synthetic lubricating oil other than polyether are contained in a specific ratio, it has excellent low-temperature fluidity, low-temperature stability, and lubricity, and is suitable for sealing materials. It has little influence and has excellent compatibility with additives, so it can be widely used in lubricating oils at low temperatures.

[Embodiments of the invention]

Examples of the present invention will be described below. In each example, parts represent parts by weight.

Production Example 1 200 parts of isotridecanol and 3 parts of potassium hydroxide
of propylene oxide was placed in an airtight container equipped with a stirrer, and the inside of the container was purged with nitrogen.
The reaction was carried out at a temperature between 150° C. and 150° C. for 4 hours. Thereafter, the mixture was aged for 1 hour to obtain 795 parts of crude polyoxypropylene glycol (10 mol) monoisotridecyl ether. After neutralizing the potassium hydroxide in the crude product with an equivalent amount of hydrochloric acid,
The mixture was dehydrated at 80 to 120° C. under a reduced pressure of 100 mm and 1 g for 1 hour, and by-product salts were filtered off to obtain 776 parts of a purified product.

Production Example 2 80 parts of polypropylene glycol (10 mol) monoisotridecyl ether produced in Production Example 1 and 4.6 parts of metallic sodium were placed in an airtight container equipped with a stirrer, and heated at 80 to 120°C under reduced pressure of 50 mm and 1 g for 10 minutes. After carrying out the sodification reaction for 1 hour, 4.25 parts of dichloromethane was pressurized into the reaction vessel under nitrogen pressure, and 80 to 1
A coupling reaction was carried out at 30° C. for 10 hours to obtain 81 parts of crude methylene bis(polyoxypropylene (10 mol) isotridecyl ether). Manufacturing example 1 of this crude product
Purification was performed in the same manner as above to obtain 76 parts of a purified product.

Hereinafter, the compounds described in each example in Table 1 were obtained by a method according to Production Example 1 and Production Example 2.

Example 1 A lubricating oil composition was prepared by mixing the compounds shown in the sample numbers in Table 1 according to their compositions. The kinematic viscosity, pour point, low temperature stability, compatibility with additives, rubber swelling properties, and lubricity of each lubricating oil composition were measured. Low-temperature stability was determined by putting the lubricating oil composition into a 100mQ measuring cylinder with a stopper, sealing it tightly, and testing it at -20°C and -40°C.
After standing in a low-temperature constant temperature bath for 24 hours, a transparent sample was rated 0, a cloudy sample was rated △, and a sample with separation was rated X. Compatibility with additives was tested using a sample containing 5% by weight of packaged additive L-3534B (manufactured by Loupliseal) to lubricating oil composition 95 heavy duty, and a test similar to the low-temperature stability test was conducted. carried out.

Rubber swelling property is NBR (N B 27 manufactured by Kureha Rubber Co., Ltd.)
0) was used as a test piece, and a test was conducted at a temperature of 120° C. for 70 hours according to JIS K-6301 vulcanized rubber physical test method, and the rate of change in elongation (%) of the test rubber piece was measured. The lubricity was tested using a Shell type four-ball tester at a temperature of 40°C, a rotation speed of 180 rpm, and a load of 40 kg for 1 minute.
Table 6 shows the results of measuring the average value of the wear scar diameter of the lower three balls.
Also listed in 1. In Table 1, (po) is an oxypropylene group, (B○) is an oxybutylene group, and α-olefin oligomer A is P manufactured by Bray Oil Comp'any.
AOL-60 (kinematic viscosity approximately 6 cS7 at 210°F), α-
Olefin oligomer B is PAOL-400 (2
It exhibits a kinematic viscosity of approximately 40 cSt) at 10°F.

According to the results in Table 1, the present invention product N containing α-olefin oligomer A as a synthetic lubricating oil other than polyether
o, 1 and comparison product No. 12, No. 14, No.
As is clear from the comparison of No. 15, No. 17, and No. 17, the product of the present invention has a low pour point, excellent low-temperature stability and compatibility with additives, small shrinkage in rubber swelling, small wear scar diameter, and good lubrication. However, the comparative products did not form a homogeneous solution (NO012, No. 17), and the elongation change rate in rubber swelling was large (No. 14).
, poor low-temperature stability and compatibility with additives (N
o, 15), the diameter of the wear scar is large and the lubricity is poor (
No. 14, No. 15), unsuitable as a lubricating oil for low temperatures. The same thing can be said for the synthesis of other than polyethers.
? 7 Invention product No. 2, which contains ester oil as oil
This is also clear from the comparison between No. 003 and comparative product No. 16.

Invention products No. 5, No. 6, and N containing two types of synthetic lubricating oils: α-olefin oligomer A and ester oil.
o, 10 and comparative product No. 11. No, 13, no.

In the comparison between No. 18, No. 19, and No. 19, the product of the present invention was superior in all items, but the comparison product had a large elongation change rate in rubber swelling (No. 11) and did not form a homogeneous solution (No. 13, No. 18),
Poor low temperature stability and compatibility with additives (No.

19), Low temperature water? i') Unsuitable as an oil. Furthermore, products No. 7 and No. 9 of the present invention, which use alkylbenzene or tricresyl phosphate as part of a synthetic lubricating oil other than polyether, are also excellent in all items.

As is clear from the above results, the product of the present invention is excellent in all properties and is found to be good as a lubricating oil for low temperatures.

Example 2 Lubricating oil compositions prepared by adding the following additives to samples No. 096, N098, No. 11, and No. 14 of Example 1 had D I N51! The FZG gear test described in i3/l was conducted.

(Additive) (% by weight) L-3534B (manufactured by Loupliseal) 5 phenyl α
-Naphthylamine 0.5 Zinc dibutyl dithiophosphate-1" (Zn amount 9,
7%) 1 (Test conditions) Test gear Test gear A Pinion gear rotation speed 216 Orpm drive gear rotation speed 144 Orpm test oil temperature 90±3°C Oil condition iQ Lubrication method Immersion test time 15 minutes The results are shown in Table 2. . In Table 2, the total wear amount is shown as the value obtained by subtracting the initial wear amount (wear amount up to the third stage) from the wear amount at the seizure stage.

Table 2 As is clear from Table 2, the product of the present invention has a higher number of wear stages and a higher number of seizure stages than the comparative product.
It can also be seen that the total wear and tear is small and the lubricity is excellent.

Agent: Patent attorney Sei Yanagi Hara

Claims (6)

[Claims] (1) A polyether compound represented by the following CI) formula or formula (11) as the A component, and a synthetic lubricating oil other than polyether that is transparently dissolved in the A component at -20°C as the B component, 1: A lubricating oil composition characterized in that it contains a lubricating oil composition in a weight ratio of 1 to 1:19. R10(AO)nR” CI) (R”0(AO)n)2CH2[II) (where, R
1 is a residue of a branched alcohol having 6 to 28 carbon atoms and whose freezing point is below 0°C; R2 is hydrogen or a residue of a branched alcohol having 1 to 2 carbon atoms;
8 is a hydrocarbon group, A is an alkylene group having 3 or 4 carbon atoms, and n is the average number of added moles of alkylene oxide having 3 or 4 carbon atoms, which is 3 to 40. ) (2) R” is isohexanol, inheptatool,
2-Ethylhexanol, isooctatool, isononanol, isodecanol, isoundecanol, isododecanol, osotridecanol, isotetradecanol, isopentadecanol, inhexadecanol, isoheptadecanol, isooctadecanol Claim 1, which is a residue of alcohol, isononadecanol, isoeicosanol, isoheneeicosanol, isodocosanol, isotoricosanol, or isotetracosanol
The lubricating oil composition described in . (3) AO is an oxypropylene group, an oxybutylene group,
The lubricating oil composition according to claim 1 or 2, wherein the lubricating oil composition is an oxytetramethylene group. (4) R'' is a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group,
Claim 1 which is a tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, or eicosyl group
The lubricating oil composition according to any one of Items 1 to 3. (5) Claims 1 to 4, wherein component B is one or more lubricating oils selected from olefin polymerized oil, ester oil, alkylbenzene oil, phosphate ester oil, and silicate ester oil. The lubricating oil composition according to any one of the above. (6) Claim 1 containing IO to 40% by weight of a polyether compound represented by formula (I) or formula (II), 2 to 60% by weight of ester oil, and 1 to 60% by weight of olefin polymerized oil. The described lubricating oil composition.