JP6939394B2 - Base oil for grease - Google Patents

Description

The present invention relates to a grease base oil contained in grease used for automobile parts. More specifically, the present invention relates to a base oil for grease oil, which is excellent in water resistance and low volatility, and is also excellent in erosion resistance to rubber such as ethylene propylene rubber (EPDM) and styrene butadiene rubber (SBR).

In order to stop global warming and air pollution, fuel efficiency regulations and exhaust regulations for automobiles are being tightened year by year. More than 100 types of motors such as power steering, wipers, and mirrors are used in automobiles, and it is required to contribute to fuel efficiency by reducing friction of various motors. Under such circumstances, the torque of the motor bearing portion is reduced by grease in order to suppress power consumption. Further, in recent years, with the electrification of automobiles, as represented by the spread of EVs and HEVs, the number of places where grease is used has increased more than before, so the role of grease has become greater.

Automobiles are required to be able to be used safely and with peace of mind in various harsh environments around the world, and this is becoming more important year by year. Therefore, greases used in automobile parts are required to have excellent water resistance and low volatility in order to adapt to the environment and minimize the occurrence of defects. In addition, grease is composed of additives such as base oil for grease, thickener, rust preventive, antioxidant and antioxidant aid, but base oil for grease such as mineral oil and synthetic oil is a constituent component. Since it accounts for 70% or more, the characteristics of the grease are greatly affected by the base oil for grease (Non-Patent Document 1).

By the way, since EPDM and SBR used for various automobile parts have low resistance to hydrocarbon oils such as mineral oil, grease based on mineral oil is rarely used as the grease around EPDM and SBR. Generally, a grease based on an alkyloxylane derivative is used. However, when an alkyloxylane derivative is used as a base oil for grease, water resistance and low volatility are often insufficient, and on the other hand, even if water resistance and low volatility are sufficient, EPDM and SBR The current situation is that it has not been able to satisfactorily prevent erosion.

Patent Document 1 reports a grease composition for a brake or a clutch using polyoxyalkylene triol or polyoxyalkylene monoalkyl ether as a base oil for grease. In the examples, a methyloxylane derivative is described, and it is said that the water resistance and low volatility are excellent by setting the average molecular weight to 2,000 to 6,000.

Patent Document 2 reports on a brake grease composition that can be used for general purposes without restrictions depending on the place of use by blending a certain amount of neopentyl polyol ester with polyoxypropylene glycol monoalkyl ether.

However, the above patent documents do not meet the needs for higher performance of grease in recent years because the performance of polyoxyalkylene triol and polyoxypropylene glycol monoalkyl ether, which are the main components, is insufficient.

Patent Document 3 reports on a base oil for a polyalkylene glycol lubricant having a narrow molecular weight distribution synthesized using _{Zn 3} [Co (CN) ₆ ] _2. When this is applied to a base oil for grease, if the molecular weight is increased until the kinematic viscosity becomes optimum for the base oil for grease by having a narrow molecular weight distribution, the erosion property to EPDM and SBR may be deteriorated. be.

Lubrication Economy, November issue, (2016)

Showa 57-179297 Showa 60-210697 JP-A-2007-217691

Therefore, there is a demand for an alkyloxylane derivative having excellent water resistance and low volatility, low erosion resistance to rubber such as EPDM and SBR, and excellent overall performance as a base oil for grease.

An object of the present invention is to provide a base oil for grease which is excellent in water resistance and low volatility and has low erosion resistance to rubber such as EPDM and SBR.

As a result of diligent studies in view of the above matters, the present inventors have found that the above-mentioned problems can be solved by a base oil for grease oil composed of a specific alkyloxylane derivative (1).

That is, the present invention is as follows.
[1] represented by Formula (1), and characterized by consisting of alkyl oxirane derivative that satisfies the relationship of M _H and M _L Togashiki calculated from the chromatogram obtained by the gel permeation chromatography measurement (2) Base oil for grease used around ethylene propylene diene rubber (EPDM) or styrene butadiene rubber (SBR).

R ¹ O- (AO) n-H ... (1)

(In equation (1),
R ¹ represents a hydrocarbon group having 1 to 22 carbon atoms.
AO represents an oxyalkylene group having 3 to 4 carbon atoms.
n represents a number of 25 or more and 150 or less. )

_{0.35 ≦ M L / M H ≦} 0.75 ···· (2)

(The elution time of the two points on the chromatogram where the length of the perpendicular line from the maximum point K where the refractive index intensity on the chromatogram is maximum to the baseline B is L and the refractive index intensity is L / 2 When the earlier point is the point O, the slower elution time is the point Q, and the intersection of the straight line G connecting the points O and the point Q and the perpendicular line drawn from the refractive index intensity maximum point K to the baseline is P. the distance between the point O and the intersection P and _{M H,} the distance between the point Q and the point of intersection P and _{M L.)}

[ 2 ] [1] A grease oil containing 10 to 100% by mass of a base oil for grease oil.

The base oil for grease composed of an alkyloxylane derivative exhibiting a specific molecular weight distribution according to the present invention is excellent in water resistance and low volatility, and further rubbers such as ethylene propylene rubber (EPDM) and styrene butadiene rubber (SBR), particularly automobiles. Has excellent corrosion resistance to rubber for parts.

FIG. 1 is a model chromatogram diagram for explaining _ML and _MH defined in the present invention. FIG. 2 is a model chromatogram diagram for explaining _{W 1/2} and W _5% as defined in the present invention. FIG. 3 is a chromatogram diagram of Synthesis Example 1. FIG. 4 is a chromatogram diagram of Comparative Synthesis Example 1.

The alkyloxylane derivative as the base oil for grease of the present invention is a compound represented by the formula (1).

R ¹ O- (AO) n-H ... (1)

In the formula (1), R ¹ is a hydrocarbon group having 1 to 22 carbon atoms, and AO is an oxyalkylene group having 3 to 4 carbon atoms. n is the average number of moles of oxyalkylene groups added, which is 25 or more and 150 or less.

In the formula (1) ^{, examples of the hydrocarbon group having 1 to 22 carbon atoms represented by R 1} include a methyl group, an ethyl group, a propyl group, an isopropyl group, an allyl group, a butyl group, an isobutyl group and a sec-butyl group. , Turt-butyl group, pentyl group, isopentyl group, hexyl group, heptyl group, cyclohexyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, Examples thereof include aliphatic hydrocarbon groups such as octadecenyl group, isooctadecyl group, octyldodecyl group and docosyl group, and aromatic hydrocarbon groups such as phenyl group, benzyl group, cresyl group, butylphenyl group and naphthyl group. Only one type or two or more types may be used.

Further, R ¹ is preferably a hydrocarbon group or octadecenyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an allyl group and a butyl group, and more preferably a methyl group and a butyl group.

AO is an oxyalkylene group having 3 to 4 carbon atoms and is an oxyalkylene group generated by ring-opening addition of an alkyloxylane having 3 or 4 carbon atoms. The alkyloxylan having 3 to 4 carbon atoms is preferably ethyloxylan or methyloxylan, and particularly preferably methyloxylan. Oxyalkylene group having 3 to 4 carbon atoms, specific examples, oxytrimethylene group _{(-O-CH 2 -CH 2 -CH} 2 -), oxy 1-methylethylene group (-O-CH (CH ₃ ) _-CH 2 -), oxytetramethylene group _{(-O-CH 2 -CH 2 -CH} 2 -CH 2 -), oxy 1-methylpropylene group _{(-O-CH (CH 3)} -CH 2 -CH 2 -), Oxy2-methylpropylene group (-O-CH ₂ -CH (CH ₃ ) -CH _2- ), oxy1-ethylethylene group (-O-CH (C ₂ H ₅ ) -CH _2- ) However, an oxy1-methylethylene group (-O-CH (CH ₃ ) -CH _2- ) by ring-opening addition of methyloxylane is particularly preferable.

Further, n is the average number of moles of oxyalkylene groups added, which is 25 or more. If n is less than 25, it may be inferior in erosion resistance, water resistance and low volatility. From this point of view, n is 25 or more, but 30 or more is more preferable.

In addition, as n increases, the viscosity increases dramatically, making it difficult to handle. From this point of view, n is 120 or less, but more preferably 100 or less.

The alkyloxylane derivative as the base oil for grease of the present invention is defined by a chromatogram obtained by using a differential refractometer in gel permeation chromatography (GPC). This chromatogram is a graph showing the relationship between the refractive index intensity and the elution time. In the alkyloxylane derivative of the present invention, the chromatogram is asymmetrical and satisfies the relationship of the formula (2). The _{closer the ML} / _MH is to 1, the more symmetrical the shape of the chromatogram is.

_{0.35 ≦ M L / M H ≦} 0.75 ···· (2)

Here, FIG. 1 is a model diagram of a chromatogram obtained by gel permeation chromatography of an alkyloxylan derivative, in which the horizontal axis represents the elution time and the vertical axis represents the refractive index intensity obtained by using a differential refractometer. show.

When the sample solution is injected into the gel permeation chromatograph and developed, elution starts from the molecule with the highest molecular weight, and the elution curve increases as the refractive index intensity increases. After that, when the refractive index intensity maximum point K at which the refractive index intensity becomes maximum is passed, the elution curve descends.

Further, in the gel permeation chromatography of the alkyloxylan derivative of the present invention, when there are a plurality of refractive index maximum points of the chromatogram, the point having the highest refractive index intensity among them is defined as the refractive index intensity maximum point K. Further, when there are a plurality of maximum points having the same refractive index intensity, the one with the slower elution time is defined as the maximum refractive index intensity point K. At this time, peaks caused by the developing solvent used for gel permeation chromatography and pseudo peaks caused by baseline fluctuations caused by the columns and devices used are excluded.

M _L / _{M H,} respectively, calculated from the chromatogram in the following manner.
(1) A perpendicular line is drawn from the maximum refractive index intensity point K on the chromatogram to the baseline B, and the length of the perpendicular line is L.
(2) Of the two points on the chromatogram having a refractive index intensity of L / 2, the one with the earlier elution time is designated as point O, and the one with the slower elution time is designated as point Q.
(3) Let P be the intersection of the straight line G connecting the points O and Q and the perpendicular line drawn from the maximum refractive index intensity point K to the baseline B.
(4) point O and the intersection point P distance _{M H} of the distance of an intersection P and the point Q and _{M L.}

Alkyl oxiranes of the present invention _is M L / _{M H} satisfies _{0.35 ≦ M L / M H ≦} 0.75. When M _L / _{M H} is greater than 0.75, erosion resistance and water resistance may be deteriorated. Also, as M L _/ M _H is reduced, the bias of the high molecular weight side is increased in the molecular weight distribution, and increase in viscosity derived therefrom seen. When M _L / _{M H} is less than 0.35, too high viscosity, difficult to handle. From this point of _view, but the a _M L / M _H 0.35 or more, more preferably to 0.38 or more, and more preferably be 0.50 or more.

In a preferred embodiment, in gel permeation chromatography, the chromatogram represented by the refractive index intensity and the elution time obtained by using a differential refractometer is asymmetrical, and the chromatograph obtained as shown below is obtained. The asymmetric value As of the peak of the gram satisfies the following equations (3) and (4).

As = W _1/2 / W _5% ... (3)
0.30 ≤ As ≤ 0.70 ... (4)

The method of calculating As will be further described with reference to the model diagram of the chromatogram of FIG. The horizontal axis shows the elution time, and the vertical axis shows the refractive index intensity obtained by using a differential refractometer.

When the sample solution is injected into the gel permeation chromatograph and developed, elution starts from the molecule with the highest molecular weight, and the elution curve increases as the refractive index intensity increases. After that, the elution curve goes down after passing the maximum refractive index intensity point at which the refractive index intensity becomes maximum.

(1) Draw a perpendicular line from the maximum refractive index intensity point K on the chromatogram to the baseline B, and let L be the length thereof.
(2) Of the two points on the chromatogram having a refractive index intensity of L / 20, the one with the earlier elution time is designated as the point R, and the one with the slower elution time is designated as the point S.
(3) Let T be the intersection of the straight line H connecting the points R and S and the perpendicular line drawn from the maximum refractive index intensity point K to the baseline B.
(4) The distance between the point R and the intersection T is W _1/2 , and the distance between the point R and the point S is W _5% .

In a preferred embodiment, As satisfies 0.30 ≦ As ≦ 0.70. By setting As to 0.70 or less, an alkyloxylane derivative as a base oil for grease having excellent water resistance, low volatility and erosion resistance can be provided.

Further, as As becomes smaller, the bias on both sides of the polymer in the molecular weight distribution becomes larger, and the resulting increase in viscosity can be seen. By setting As to 0.30 or more, it is possible to prevent the viscosity from becoming high and the handling from being significantly deteriorated. From this viewpoint, As is preferably 0.50 or more, and more preferably 0.60 or more.

In the present _invention, M L, _M gel permeation chromatography to determine the _H and As (GPC) is, SHODEX KF SHODEX as a system (R) GPC101GPC dedicated system, SHODEX RI-71s as a differential refractometer, as a guard column -G, three SHODEX KF804L as a column were continuously mounted, the column temperature was 40 ° C., tetrahydrofuran was flown as a developing solvent at a flow rate of 1 ml / min, and 0.1 ml of a 0.1 wt% tetrahydrofuran solution of the obtained reaction product was injected. Then, a BORWIN GPC calculation program is used to obtain a chromatogram represented by the refractive refractometer intensity and the elution time.

When producing an alkyloxylane derivative as a base oil for grease of the present invention, preferably, in the presence of a composite metal cyanide catalyst (hereinafter abbreviated as DMC catalyst) as an initiator, the number of carbon atoms is 3 or 4. Alkyloxylane, especially methyloxylane, is added by ring opening. An initiator having at least one hydroxyl group in the molecule and a DMC catalyst are added to the reaction vessel to bring the inside of the reaction vessel into an inert gas atmosphere, and then alkyloxylane is continuously added under pressure or atmospheric pressure. Addition polymerization is carried out by adding intermittently and stirring.

At this time, the average supply rate of alkyloxylane does not matter, but in order to produce it stably, it is desirable to change it according to the total molar equivalent of alkyloxylane charged with respect to the initiator. Specifically, the average supply rate of alkyloxylan when the total molar equivalent of alkyloxylan is less than 60 with respect to the initiator, V ₁ = 2 to 50 molar equivalents / hour, and the total molar equivalent of alkyloxylan is 60 or more. , Average supply rate of alkyloxylan when less than 100 V ₂ = 4 to 40 molar equivalents / hour, average supply rate of alkyloxylan when the total molar equivalent of alkyloxylan is 100 or more and 150 or less V ₃ = 5 It is preferred to control the average supply rate of alkyloxylan to 30 molar equivalents / hour.

The reaction temperature is preferably 50 ° C. to 150 ° C., more preferably 70 ° C. to 110 ° C. If the reaction temperature is higher than 150 ° C., the catalyst may be deactivated. If the reaction temperature is lower than 50 ° C., the reaction rate is slow and the productivity is poor.

Specific examples of the initiator in the present invention include, but are not limited to, the following.
Methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, allyl alcohol, butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, pentyl alcohol, isopentyl alcohol, neopentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol , Nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, nonadecil alcohol, icosyl alcohol, henikosyl alcohol, Docosyl alcohol, tricosyl alcohol, butyl propylene glycol, etc. Methyloxylan adducts of these initiators can also be used as initiators as well. Further, the amount of water contained in the initiator is not particularly limited, but it is desirable that the amount of water contained in the initiator is 0.5 wt% or less.

The amount of the DMC catalyst used is not particularly limited, but is preferably 0.0001 to 0.1 wt%, more preferably 0.001 to 0.05 wt% with respect to the alkyloxylane derivative to be produced. The DMC catalyst may be introduced into the reaction system all at once at the beginning, or may be introduced in a sequential manner. After completion of the polymerization reaction, the composite metal complex catalyst is removed. The catalyst can be removed by filtration, adsorbent treatment, or the like.

A known DMC catalyst can be used in the present invention, and can be represented by, for example, the formula (5).

Ma [M'x (CN) y] b (H ₂ O) c · (R) d ... (5)

In formula (5), M and M'are metals, R is an organic ligand, a, b, x and y are positive integers that vary depending on the valence and coordination number of the metal, and c and d are metals. It is a positive integer that changes depending on the coordination number of.

Examples of the metal M include Zn (II), Fe (II), Fe (III), Co (II), Ni (II), Al (III), Sr (II), Mn (II), Cr (III), Examples thereof include Cu (II), Sn (II), Pb (II), Mo (IV), Mo (VI), W (IV), W (VI), and Zn (II) is preferably used.

Examples of the metal M'are Fe (II), Fe (III), Co (II), Co (III), Cr (II), Cr (III), Mn (II), Mn (III), Ni (II). , V (IV), V (V) and the like, and among them, Fe (II), Fe (III), Co (II) and Co (III) are preferably used.

As the organic ligand R, alcohol, ether, ketone, ester and the like can be used, and alcohol is more preferable. Preferred organic ligands are water-soluble, and specific examples thereof include tert-butyl alcohol, n-butyl alcohol, iso-butyl alcohol, N, N-dimethylacetamide, ethylene glycol dimethyl ether (glyme), and diethylene glycol dimethyl ether ( Diglyme) and the like. Particularly preferably, it is Zn ₃ [Co (CN) ₆ ] ₂ coordinated with tert-butyl alcohol.

The alkyloxylane derivative as the base oil for grease of the present invention may be used alone as a grease oil, or may be mixed with another base oil for grease to be used as a grease oil. When the total mass of the grease oil is 100% by mass, the mass ratio of the base oil for grease oil of the present invention is preferably 10 to 100% by mass. By setting the concentration of the base oil for grease oil of the present invention to 10% by mass or more, the effect of the present invention can be more remarkably exhibited. From this viewpoint, the concentration of the base oil for grease oil of the present invention is more preferably 50% by mass or more.

Further, the base oil and additives other than the base oil for grease oil of the present invention are not particularly limited as long as they can be used for grease, but the following can be exemplified.
Examples of the base oil include mineral oil, olefin synthetic oil, ester oil, polyoxypropylene glycol monoalkyl ether synthesized by a general method, castor oil and the like.
As the thickener, natural animal and vegetable oils such as beef tallow, palm oil and palm oil, hydrogenated oils obtained by adding natural animal and vegetable oils such as hydrogenated castor oil, and various fatty acids obtained by decomposing these oils and fats. Examples thereof include soap-based metals such as sodium, calcium, lithium, aluminum and barium, and non-hydrogenated soaps such as silica gel, benton, polyurea and polytetrafluoroethylene.
Additives include antioxidants such as phenol-based, amine-based, and phosphoric acid ester-based, metal sulfonate-based, amine-based, metal soap-based, and ester-based rust preventives, molybdenum disulfide, tungsten disulfide, and nitride. Examples include anti-wear agents such as boron.

Hereinafter, the present invention will be described in detail with reference to examples.
(Reference synthesis example: Synthesis of complex metal cyanide complex catalyst)
In an aqueous solution of 2.0ml containing zinc chloride 2.1 g, an aqueous solution of potassium hexacyanocobaltate _K 3 Co _{(CN) 6} and comprises 0.84 g 15 ml, was added dropwise over 15 minutes with agitation at 40 ° C.. After completion of the dropping, 16 ml of water and 16 g of tert-butyl alcohol were added, the temperature was raised to 70 ° C., and the mixture was stirred for 1 hour. After cooling to room temperature, a filtration operation (first filtration) was performed to obtain a solid. To this solid, 14 ml of water and 8.0 g of tert-butyl alcohol were added, and the mixture was stirred for 30 minutes and then filtered (second filtration) to obtain a solid.

Further, once again, 18.6 g of tert-butyl alcohol and 1.2 g of methanol were added to this solid, and after stirring for 30 minutes, a filtration operation (third filtration) was performed, and the obtained solid was dried at 40 ° C. under reduced pressure for 3 hours. Then, 0.7 g of a composite metal cyanide complex catalyst was obtained.

(Synthesis Example 1)
Reference with 200 g of butyl propylene glycol for a stainless steel 5 liter (internal volume 4,890 ml) pressure resistant reactor equipped with a thermometer, pressure gauge, safety valve, nitrogen gas blow pipe, stirrer, vacuum exhaust pipe, cooling coil, and steam jacket. 0.2 g of the composite metal cyanide complex catalyst of the synthesis example was charged. After nitrogen substitution, the temperature was raised to 110 ° C., and 210 g of methyloxylan was charged from a nitrogen gas blowing tube under the condition of 0.3 MPa or less over 4 hours. At this time, the changes over time in the pressure and temperature in the reaction vessel were measured.

After 4 hours, the pressure in the reaction vessel decreased sharply. Then, while keeping the inside of the reaction vessel at 110 ° C., methyloxylane was gradually added from the nitrogen gas blowing tube under the condition of 0.6 MPa or less, and 2,841 g of methyloxylan was continuously pressurized and added under stirring. bottom. At this time, the time until 840 g of methyloxylan was added was 60 minutes, the time until 2,100 g was added was 108 minutes, and the time until 2,841 g was added was 132 minutes.

After completion of the addition, the mixture was reacted at 110 ° C. for 1 hour, and then 1,680 g was withdrawn from the reaction vessel. The temperature of the residue in the reaction vessel was raised to 110 ° C., and 696 g of methyloxylane was added over 77 minutes from a nitrogen gas blowing tube under the condition of 0.6 MPa or less. After completion of the addition, the reaction was carried out at 110 ° C. for 1 hour, and then 1,188 g was taken out from the reaction vessel again, and while blowing nitrogen gas, the pressure was reduced at 75 to 85 ° C. and 50 to 100 Torr for 1 hour, and then filtration was performed.

The obtained reaction product was measured by gel permeation chromatography.
For gel permeation chromatography, a system dedicated to SHODEX GPC101GPC, a differential refractometer SHODEX RI-71S, a guard column SHODEX KF-GS, and three HODEX KF804L columns were continuously mounted, and the column temperature was 40 ° C. and the developing solvent was used. As a result, tetrahydrofuran was flowed at a flow rate of 1 ml / min, 0.1 ml of a 0.1 wt% tetrahydrofuran solution of the obtained reaction product was injected, and a chromatograph represented by a refractive refractometer intensity and an elution time was used using a BORWIN GPC calculation program. Got a gram. FIG. 3 is the obtained chromatogram. From this chromatogram, _ML / _MH was 0.62 and As was 0.65.

(Synthesis Example 2)
A reaction product was obtained by carrying out the reaction in the same manner as in Synthesis Example 1 except that 360 g of tetradecyl alcohol was used instead of butylpropylene glycol as an initiator. The obtained reaction product was measured by gel permeation chromatography. As a _{result, M} L / M _H is 0.74, As was 0.64.

(Synthesis Example 3)
A reaction product was obtained by carrying out the reaction in the same manner as in Synthesis Example 1 except that 130 g of methyl propylene glycol was used instead of butyl propylene glycol as an initiator. The obtained reaction product was measured by gel permeation chromatography. As a _{result, M} L / M _H is 0.61, As was 0.65.

(Synthesis Example 4)
A reaction product was obtained by carrying out the reaction in the same manner as in Synthesis Example 1 except that 463 g of tetradecyl alcohol was used instead of butylpropylene glycol as an initiator. The obtained reaction product was measured by gel permeation chromatography. As a _{result, M} L / M _H is 0.73, As was 0.69.

(Comparative Synthesis Example 1)
A stainless steel 5 liter (internal volume 4,890 ml) pressure resistant reactor equipped with a thermometer, pressure gauge, safety valve, nitrogen gas blow pipe, stirrer, vacuum exhaust pipe, cooling coil, and steam jacket, with 320 g of butanol and hydroxide. 78 g of potassium was charged. After reacting 1,695 g of methyloxylane at 110 ° C. for 6 hours, 1,865 g was withdrawn from the reaction vessel. 2,630 g of methyloxylane was further reacted with the residue in the reaction vessel over 20 hours. Then, the remaining methyloxylan is removed under reduced pressure at 75 to 85 ° C. for 30 minutes, the reaction product is transferred to a 5 L eggplant flask, immediately neutralized with 1N hydrochloric acid, dehydrated in a nitrogen gas atmosphere, and then filtered. rice field.

The obtained reaction product was measured by gel permeation chromatography. FIG. 4 is the obtained chromatogram. From this _{chromatogram, M} L / M _H is 1.44, As was 2.95.

(Comparative Synthesis Example 2)
A stainless steel 5 liter (internal volume 4,890 ml) pressure resistant reactor equipped with a thermometer, pressure gauge, safety valve, nitrogen gas blow pipe, stirrer, vacuum exhaust pipe, cooling coil, and steam jacket, with 115 g of butanol and hydroxide. 9 g of potassium was charged. After reacting 3,166 g of methyloxylane at 110 ° C. for 13 hours, 1,865 g was withdrawn from the reaction vessel. Further, 1,184 g of methyloxylane was reacted with the residue in the reaction vessel over 10 hours. Then, the remaining methyloxylan is removed under reduced pressure at 75 to 85 ° C. for 30 minutes, the reaction product is transferred to a 5 L eggplant flask, immediately neutralized with 1N hydrochloric acid, dehydrated in a nitrogen gas atmosphere, and then filtered. rice field.

The obtained reaction product was measured by gel permeation chromatography. As a _{result, M} L / M _H is 1.25, As was 1.89.

_{Table 1 shows the values of ML} / _MH and As obtained from the chromatograms of Synthesis Examples 1 to 4 and Comparative Synthesis Examples 1 and 2, and the characteristics of the compound.
In Comparative Synthesis Example 1, since the chromatogram does not have one maximum refractive index point and is not a single-peak system peak, _{the values of ML} / _MH and As at the peak having the maximum refractive index maximum point are shown. ..
The kinematic viscosity in Table 1 was measured in accordance with JIS K-2283, and the molecular weight was calculated from the hydroxyl value.

(Examples 1 to 3 and Comparative Example 1)
The water resistance, volatility and erosion resistance of the grease base oil shown in Table 1 were evaluated.
(Water resistance evaluation method)
The base oil for grease and water were weighed equally in a glass container, stirred 10 times with a stirring rod, and allowed to stand at room temperature for 24 hours, and then the appearance was observed to evaluate the water resistance. The evaluation criteria are as follows.
(Water resistance evaluation standard)
The base oil for grease and water are completely separated: ○
Grease base oil and water are not completely separated: ×

(Volatility evaluation method)
Volatility was evaluated with a simultaneous differential heat calorie measuring device (TG / DTA7220, Hitachi High-Tech Science Corporation). The measurement conditions are a measurement start temperature of 30 ° C., a temperature rise rate of 10 ° C./min, an air introduction amount of 75 mL / min, and after reaching 150 ° C., the temperature is maintained for 2 hours and then cooled. Evaluation was performed.
(Volatility evaluation standard)
Weight loss rate is less than 3.0%: ○
Weight loss rate is 3.0% or more: ×

(Erosion resistance evaluation method)
The test was conducted in accordance with JIS-2228 (rubber swelling test method for non-mineral oil-based rubber lubricants for automobile brakes). EPDM was used as a rubber test piece, and the test was carried out under the conditions of 120 ° C. × 5 hr. Erosion resistance was evaluated based on the weight change rate of EPDM.
(Erosion resistance evaluation standard)
The rate of change in weight of EPDM is less than 5.0%: ○
The rate of change in weight of EPDM is 5.0% or more: ×

As shown in the results of Table 2, it was confirmed that Examples 1 to 4 using the grease base oil according to the present invention were excellent in water resistance, low volatility and erosion resistance.

Comparative Example 1 had the same alkyl chain as the base oil for grease used in Example 1 and had the same kinematic viscosity, but was inferior in corrosion resistance because it had a molecular weight distribution outside the range of the present invention.
In Comparative Example 2, the grease base oil and the alkyl chain used in Example 1 are the same as in Synthesis Example 1, and the kinematic viscosity is similar to that of the grease base oil used in Example 4, but the scope of the present invention is Since it has an outer molecular weight distribution, it was inferior in water resistance and low volatility.

Claims (2)

Is represented by the formula (1), and characterized by comprising the alkyl oxirane derivative that satisfies the relationship of M _H and M _L Togashiki calculated from the chromatogram obtained by the gel permeation chromatography measurement (2), Base oil for grease used around ethylene propylene diene rubber (EPDM) or styrene butadiene rubber (SBR).

R ¹ O- (AO) n-H ... (1)

(In equation (1),
R ¹ represents a hydrocarbon group having 1 to 22 carbon atoms.
AO represents an oxyalkylene group having 3 to 4 carbon atoms.
n represents a number of 25 or more and 150 or less. )

_{0.35 ≦ M L / M H ≦} 0.75 ···· (2)

(The elution time of the two points on the chromatogram where the length of the perpendicular line from the maximum point K where the refractive index intensity on the chromatogram is maximum to the baseline B is L and the refractive index intensity is L / 2 When the earlier point is the point O, the slower elution time is the point Q, and the intersection of the straight line G connecting the points O and the point Q and the perpendicular line drawn from the refractive index intensity maximum point K to the baseline is P. the distance between the point O and the intersection P and _{M H,} the distance between the point Q and the point of intersection P and _{M L.)}
A grease oil containing 10 to 100% by mass of the base oil for grease oil according to claim 1.

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