Polyalkylene diol modified product

Abstract

A modified polyalkylene diol represented by general formula (1), wherein the number average molecular weight of the corresponding polyalkylene diol is 100-8000. (In general formula (1), the multiple R1 may be the same or different and each independently represent a C2-5 linear alkylene group or a C3-8 branched chain alkylene group in which the main chain of the branched chain alkylene group has 2-5 carbon atoms, Q1 and Q2 may be the same or different and each independently represent a silyl group represented by general formula (3), and n represents an integer of 2 or more.) (In general formula (2), R2, R3, and R4 may be the same or different and each independently is a C1-9 hydrocarbon group.)

Description

Technical Field

[0001] The present invention relates to a polyalkylene diol modified product, and more particularly to a polyalkylene diol modified product that can be preferably used as a synthetic lubricating base oil having a high viscosity index.

Background Art

[0002] Lubrication is an essential element for reducing friction and wear of members and improving the energy efficiency and lifespan of devices in various mechanical devices having movable parts.

[0003] As lubricants, lubricating compositions containing a lubricating base oil, optionally a thickener, and optionally one or more performance additives are used in a wide range of fields. Examples of such lubricating compositions include lubricating oils and greases (semi-solid lubricants).

[0004] The lubricating base oil is the base material of the lubricating composition. The lubricating base oil is required to have a viscosity suitable for lubrication in the temperature range in which the lubricating composition is used. Generally, the viscosity of a fluid decreases at high temperatures and increases at low temperatures. In order for the lubricating composition to be usable in a wide temperature range, it is desirable that the temperature dependence of the viscosity of the lubricating base oil is small, that is, the viscosity index of the lubricating base oil is high.

[0005] The API base oil classification defined by the American Petroleum Institute (API) classifies lubricating base oils into five categories of Group I to V. Group I base oils are mineral oil-based base oils having a sulfur content of more than 0.03% by mass and / or a saturation of less than 90% by mass and a viscosity index of 80 or more and less than 120. Group II base oils are mineral oil-based base oils having a sulfur content of 0.03% by mass or less, a saturation of 90% by mass or more, and a viscosity index of 80 or more and less than 120. Group III base oils are mineral oil-based base oils having a sulfur content of 0.03% by mass or less, a saturation of 90% by mass or more, and a viscosity index of 120 or more. Group IV base oils are polyalphaolefin base oils. Group V base oils are base oils other than the above Groups I to IV.

[0006] Group III base oils, which are mineral oil-based base oils with the highest viscosity index, are generally produced through hydrocracking and hydrorefining processes, or by a wax isomerization process that isomerizes waxes such as wax obtained from the Fischer-Tropsch process (FT wax) or wax obtained from the Gas-to-Liquid process (GTL wax). The viscosity index achievable with these conventional mineral oil-based base oils is generally around 135. For applications requiring a higher viscosity index, synthetic base oils such as poly-α-olefin base oils (Group IV base oils) and ester base oils (Group V base oils) are used.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, these conventional synthetic base oils do not necessarily have chemical properties suitable for all applications.

[0009] An object of the present invention is to provide a novel functional fluid that can be suitably used as a lubricating base material with a high viscosity index.

Means for Solving the Problems

[0010] The present invention includes the following embodiments [1] to [6]. [1] A polyalkylene diol modified product represented by the following general formula (1), wherein the number average molecular weight of the corresponding polyalkylene diol is 100 to 8000.

[0011]

Chemical Formula

[0012]

Chemical formula

[0013] [2] In the general formula (1), R 1 is an ethane-1,2-diyl group, a propane-1,2-diyl group, a butane-1,2-diyl group, a butane-2,3-diyl group, or a butane-1,4-diyl group, or a combination thereof, and the polyalkylene diol-modified product according to [1].

[0014] [3] In the general formula (1), Q 1 and Q 2is one or more silyl groups selected from a trimethylsilyl group, an ethyldimethylsilyl group, a dimethylpropylsilyl group, a butyldimethylsilyl group, an octyldimethylsilyl group, a triethylsilyl group, a dimethylisopropylsilyl group, a diethylisopropylsilyl group, a triisopropylsilyl group, a tributylsilyl group, a tert-butyldimethylsilyl group, a dimethylphenylsilyl group, a benzyldimethylsilyl group, a methyldiphenylsilyl group, a tert-butyldiphenylsilyl group, a triphenylsilyl group, a di-tert-butylisobutylsilyl group, a tricyclohexylsilyl group, a dicyclohexylphenylsilyl group, and a cyclohexyldiphenylsilyl group, the polyalkylene diol modified product according to [1] or [2].

[0015] [4] In the general formula (1), Q 1 and Q 2 are the same silyl group, or are the same combination of two or more silyl groups, the polyalkylene diol modified product according to any one of [1] to [3].

[0016] [5] A lubricating base oil containing the polyalkylene diol modified product according to any one of [1] to [4].

[0017] [6] A lubricating oil composition containing the lubricating base oil according to [5].

Advantages of the Invention

[0018] The polyalkylene diol modified product, which is a functional fluid according to the first aspect of the present invention, can be suitably used as a lubricating base material having a high viscosity index. According to the lubricating base oil according to the second aspect of the present invention, by containing the polyalkylene diol modified product according to the first aspect of the present invention, it is possible to increase the viscosity index. According to the lubricating oil composition according to the third aspect of the present invention, by containing the lubricating base oil according to the second aspect of the present invention, it is possible to improve the temperature-viscosity characteristics of the entire composition.

Modes for Carrying Out the Invention

[0019] Hereinafter, the present invention will be described in detail. In this specification, unless otherwise specified, the notation "A to B" for numerical values A and B is equivalent to "A or more and B or less". When a unit is attached only to numerical value B in such notation, the said unit shall also be applied to numerical value A. In this specification, the words "or" and "or else" shall mean logical sum unless otherwise specified. In this specification, for elements E 1 and E 2 the notation "E 1 and / or E 2 " is equivalent to "E 1 , or E 2 , or a combination thereof", and for N elements E 1 , …, E i , …, E N (N is an integer of 3 or more), the notation "E 1 , …, and / or E N " is equivalent to "E 1 , …, or E i , …, or E N , or a combination thereof" (i is a variable taking values of all integers satisfying 1 < i < N). Also in this specification, "alkaline earth metal" shall include magnesium.

[0020] In this specification, "(meth)acrylate" means "acrylate and / or methacrylate".

[0021] In this specification, "diol" is interpreted in the broadest sense and means a divalent alcohol. Unless otherwise specified, the positional relationship of the two hydroxy groups in "diol" is not restricted.

[0022] In this specification, unless otherwise specified, the contents of each element of calcium, magnesium, zinc, phosphorus, sulfur, boron, barium, and molybdenum in the oil are measured by inductively coupled plasma optical emission spectrometry (intensity ratio method (internal standard method)) in accordance with JIS K0116. Also, the content of nitrogen element in the oil is measured by chemiluminescence method in accordance with JIS K2609. In this specification, "weight average molecular weight" and "number average molecular weight" mean the weight average molecular weight and number average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC). The measurement conditions of GPC are as follows. [GPC Measurement Conditions] Apparatus: ACQUITY (registered trademark) APC UV RI System manufactured by Waters Corporation Columns: In order from the upstream side, one ACQUITY (registered trademark) APC XT125A (gel particle size 2.5 μm, column size (inner diameter × length) 4.6 mm × 150 mm) manufactured by Waters Corporation and two ACQUITY (registered trademark) APC XT45A (gel particle size 1.7 μm, column size (inner diameter × length) 4.6 mm × 150 mm) manufactured by Waters Corporation are connected in series Column Temperature: 40 °C Sample Solution: Tetrahydrofuran solution with a sample concentration of 1.0 mass% Eluent: Tetrahydrofuran Solution Injection Volume: 20.0 μL Flow Rate: 0.7 mL / min Detector: Differential Refractometer Reference Substance: 10 points of standard polystyrene (Agilent EasiCal (registered trademark) PS-1 manufactured by Agilent Technologies) (molecular weights: 30230, 9590, 2970, 890, 786, 682, 578, 474, 370, 266)

[0023] <1. Polyalkylene Diol Modified Product> The polyalkylene diol-modified product according to the first aspect of the present invention (hereinafter sometimes simply referred to as "polyalkylene diol-modified product") is a polyalkylene diol-modified product in which the number average molecular weight of the corresponding polyalkylene diol is 100 to 8000, and has a structure represented by the following general formula (1).

[0024] [Chemical formula] (In general formula (1), a plurality of Rs 1 may be the same or different from each other, and each independently represents a linear alkylene group having 2 to 5 carbon atoms, or a branched alkylene group having 3 to 8 carbon atoms and having 2 to 5 carbon atoms in the main chain, and Q 1 and Q 2 may be the same or different from each other, and each independently represents a silyl group represented by the following general formula (2), and n represents an integer of 2 or more.)

[0025] [Chemical formula] (In general formula (2), R 2 , R 3 , and R 4 may be the same or different from each other, and each independently represents a hydrocarbon group having 1 to 9 carbon atoms.)

[0026] The corresponding polyalkylene diol is obtained by replacing Q 1 and Q 2 with hydrogen atoms in general formula (1), and is represented by the following general formula (3).

[0027] [Chemical formula] The number average molecular weight of the corresponding polyalkylene diol is 100 or more, preferably 150 or more, more preferably 200 or more, from the viewpoints of reducing volatility and enhancing abrasion resistance. Further, from the viewpoint of reducing viscosity and enhancing energy saving property, it is 8000 or less, preferably 6000 or less, more preferably 5000 or less, and in one embodiment 2500 or less. In one embodiment, it can be 100 to 8000, or 150 to 6000, or 200 to 5000, or 200 to 2500.

[0028] When a certain polyalkylene diol modified product is provided, the number average molecular weight of the corresponding polyalkylene diol can be determined as follows. i) Identify the silyl group Q 1 , Q 2 . The number and the abundance ratio of different silyl groups can be confirmed by measuring the 29 Si NMR spectrum of the polyalkylene diol modified product. Further, by performing a treatment to cleave the Si-O bond of the polyalkylene diol modified product and isolating the resulting low molecular weight silicon compound, the structure of the silyl group can be identified. When the abundance ratio of a plurality of different silyl groups cannot be determined by measuring the 29 Si NMR spectrum of the polyalkylene diol modified product, the abundance ratio of each silyl group can be confirmed from the amount of each isolated silicon compound. The treatment for cleaving the Si-O bond of the polyalkylene diol modified product is carried out under the same conditions as the silyl deprotection of alcohol (for example, reacting with TBAF at room temperature for 1 to 5 hours in a tetrahydrofuran solvent) using a reagent that acts as a fluoride ion source (typically tetrabutylammonium fluoride (TBAF) or HF-pyridine). The silicon compound obtained corresponding to the silyl group of the general formula (3) by this reaction has the structure of F-SiR 3 R 4 R 5 . The determination of R 3 ~R 5 is 1 H NMR spectrum, and, if necessary, 13It can be carried out based on common sense methods in the field of organic chemistry by known analysis means such as 13C NMR spectrum, IR spectrum, mass spectrometry (MS), etc. ii) Recover the polyalkylene diol simultaneously obtained in the Si-O cleavage reaction (deprotection reaction) of i) above, and measure its number average molecular weight Mn' by GPC. The measured Mn' is the number average molecular weight Mn PAG of the corresponding polyalkylene diol. In addition, when the silyl groups Q 1 and Q 2 are the same and single silyl group, instead of the above step ii), the following step ii') may be carried out as a simple method. ii') Measure the number average molecular weight Mn'' of the whole polyalkylene diol modified product by GPC. Based on the measured Mn'' and the molecular weight M silyl of the silyl group, the number average molecular weight Mn PAG of the corresponding polyalkylene diol is obtained by the following formula (1). Mn PAG = Mn'' - M silyl + 2.016 …(1)

[0029] In the general formula (1), R 1 is a linear alkylene group having 2 to 5 carbon atoms, or a branched alkylene group having 3 to 8 carbon atoms and having 2 to 5 carbon atoms in the main chain. When R 1 is a linear alkylene group, the number of carbon atoms of R 1 is preferably 2 to 4. When R 1 is a branched alkylene group, the number of carbon atoms of R 1 is preferably 3 to 6, and the number of carbon atoms in the main chain of R 1 is preferably 2 to 4. However, the number of carbon atoms of R 1 is always equal to or more than the number of carbon atoms in the main chain. In this specification, the number of carbon atoms in the main chain of R 1 means the number of carbon atoms of the shortest carbon chain connecting the two oxygen atoms bonded to R 1 , and is determined regardless of the selection of the main chain used in the naming of R 1 . For example, when R 1 is a butane-1,2-diyl group, R 1The main chain of [substance] has 2 carbon atoms. R 1 When [substance] is a linear alkylene group, R 1 The number of carbon atoms in the main chain of [substance] is equal to the number of carbon atoms in R 1 When [substance] is a branched alkylene group, R 1 The side chain of [substance] is a linear or branched alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and may be a methyl group in one embodiment. An alkylene group R 1 having an integer Y (Y is an integer from 2 to 8) of carbon atoms (the number of carbon atoms in the main chain is Z (Z is an integer from 2 to 5, Y≥Z)) of the repeating unit R 1 O can be obtained by ring-opening polymerization of an unsubstituted or substituted Z+1-membered ring saturated aliphatic cyclic ether having Y carbon atoms. Ring-opening polymerization of an unsubstituted cyclic ether is R 1 gives an alkylene oxide repeating unit R 1 where [substance] is a linear alkylene group, and ring-opening polymerization of a substituted cyclic ether is R 1 gives a repeating unit R 1 where [substance] is a branched alkylene group. Preferred examples of the alkylene group R 1 O. Preferred examples of the alkylene group R 1 include alkylene groups having 2 carbon atoms in the main chain such as ethane-1,2-diyl group, propane-1,2-diyl group, butane-1,2-diyl group, butane-2,3-diyl group, pentane-1,2-diyl group, hexane-1,2-diyl group, heptane-1,2-diyl group, octane-1,2-diyl group, etc.; alkylene groups having 3 carbon atoms in the main chain such as propane-1,3-diyl group, 3-methylbutane-1,3-diyl group, 2,2-dimethylpropane-1,3-diyl group, etc.; alkylene groups having 4 carbon atoms in the main chain such as butane-1,4-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group, hexane-1,4-diyl group, 4-methylpentane-1,4-diyl group, hexane-2,5-diyl group, etc.; and alkylene groups having 5 carbon atoms in the main chain such as pentane-1,5-diyl group, 3-methylpentane-1,5-diyl group, etc. R 1 may be a single alkylene group or a combination of two or more alkylene groups.

[0030] In one preferred embodiment, the alkylene group R1 may be an ethane-1,2-diyl group, a propane-1,2-diyl group, a butane-1,2-diyl group, a butane-2,3-diyl group, or a butane-1,4-diyl group, or a combination thereof.

[0031] The cyclic ether that gives the alkylene oxide repeating unit R 1 O by ring-opening polymerization, preferred examples of which include ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, 1,2-pentylene oxide, 1,2-hexylene oxide, 1,2-heptylene oxide, 1,2-octylene oxide, etc., unsubstituted or substituted 3-membered ring ethers; oxetane (trimethylene oxide), 2,2-dimethyloxetane, 3,3-dimethyloxetane, etc., unsubstituted or substituted 4-membered ring ethers; tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, etc., unsubstituted or substituted 5-membered ring ethers; and tetrahydropyran, 4-methyltetrahydropyran, etc., unsubstituted or substituted 6-membered ring ethers. The alkylene oxide repeating unit R 1 O may consist of a repeating unit corresponding to one kind of cyclic ether, or may be a combination of repeating units corresponding to two or more kinds of cyclic ethers.

[0032] In the general formula (1), n is an integer of 2 or more. Usually, n has a distribution, and the number average molecular weight is determined corresponding to the distribution of n.

[0033] In the general formula (2), R 2 , R 3 , and R 4 may be the same or different from each other, and each independently is a hydrocarbon group having 1 to 9 carbon atoms. Preferred examples of the hydrocarbon group include an alkyl group (which may have a ring structure), an aryl group, an alkylaryl group, an arylalkyl group, etc.

[0034] R2 ~R 4 Regarding ~R, the alkyl group may be a linear alkyl group, a branched alkyl group, or may have a ring structure. Examples of the chain alkyl group having 1 to 9 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, 1-ethylpropyl group, hexyl group, isohexyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, heptyl group, octyl group, isooctyl group, 2-ethylhexyl group, and nonyl group. Examples of the ring structure that the alkyl group may have include cycloalkyl rings having 5 to 7 carbon atoms such as cyclopentyl ring, cyclohexyl ring, and cycloheptyl ring. The cycloalkyl ring may further have an alkyl substituent and / or an alkylene substituent, and the substitution position on those cycloalkyl rings is arbitrary. Preferred examples of the alkyl group having 1 to 9 carbon atoms and having a ring structure include cyclopentyl group, cyclohexyl group, cycloheptyl group, methylcyclopentyl group, cyclopentylmethyl group, methylcyclohexyl group, cyclohexylmethyl group, etc.

[0035] R 2 ~R 4 Regarding ~R, examples of the aryl group, alkylaryl group, and arylalkyl group having 1 to 9 carbon atoms include phenyl group, tolyl group, xylyl group, mesityl group, cumyl group, and benzyl group.

[0036] Q 1 and Q 2Regarding the silyl group represented by the general formula (2), preferred examples thereof include a trimethylsilyl group, an ethyldimethylsilyl group, a dimethylpropylsilyl group, a butyldimethylsilyl group, an octyldimethylsilyl group, a triethylsilyl group, a dimethylisopropylsilyl group, a diethylisopropylsilyl group, a triisopropylsilyl group, a tributylsilyl group, a tert-butyldimethylsilyl group, a dimethylphenylsilyl group, a benzyldimethylsilyl group, a methyldiphenylsilyl group, a tert-butyldiphenylsilyl group, a triphenylsilyl group, a di-tert-butylisobutylsilyl group, a tricyclohexylsilyl group, a dicyclohexylphenylsilyl group, and a cyclohexyldiphenylsilyl group, and the like. In one embodiment, Q 1 and Q 2 are preferably one or more silyl groups selected from a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, a tert-butyldimethylsilyl group, a dimethylphenylsilyl group, and a tert-butyldiphenylsilyl group.

[0037] In one embodiment, Q 1 and Q 2 can be the same and one kind of silyl group. Such a polyalkylene glycol modified product can be obtained by using one kind of silylating agent alone as the silylating agent in the production method described later. In another embodiment, Q 1 and Q 2 can be the same combination of two or more silyl groups. Such a polyalkylene glycol modified product can be obtained by using two or more silylating agents in combination as the silylating agent in the production method described later.

[0038] (Production) The polyalkylene glycol modified product of the present invention is similar to the silyl protection of a general primary or secondary alcohol. A corresponding polyalkylene glycol and a silylating agent (X 1 -SiR 2 R 3 R4 ) Therefore, it can be produced, for example, by the reaction represented by the following general formula (4). As the silylating agent, one silylating agent may be used alone, or two or more silylating agents may be used in combination. For example, when a silylating agent A' corresponding to the silyl group A and a silylating agent B' corresponding to the silyl group B are used in combination, the polyalkylene diol-modified product (silylated product) obtained is such that Q 1 and Q 2 in the general formula (1) are both polyalkylene diol-modified products with silyl group A, and Q 1 and Q 2 are both polyalkylene diol-modified products with silyl group B, and Q 1 and Q 2 is a mixture of a polyalkylene diol-modified product in which one of them is silyl group A and the other is silyl group B. Also, when the silylating agent A' corresponding to the silyl group A is used alone to produce a first polyalkylene diol-modified product in which both Q 1 and Q 2 are silyl group A, and the silylating agent B' corresponding to the silyl group B is used alone to produce a second polyalkylene diol-modified product in which both Q 1 and Q 2 are silyl group B, and optionally, silylating agents C' (, D',...) corresponding to one or more other silyl groups C (, D,...) are also each used alone to produce one or more polyalkylene diol-modified products respectively. After that, by mixing these two or more produced polyalkylene diol-modified products, Q 1 and Q 2 may be a mixture of two or more polyalkylene diol-modified products in which the same silyl group is present.

[0039]

Chemical formula

[0040] The reaction of General Formula (4) can be carried out in an aprotic solvent or without a solvent. Examples of the solvent include hydrocarbon solvents such as benzene, toluene, xylene, hexane, petroleum ether, cyclohexane, and methylcyclohexane; halogenated hydrocarbon solvents such as dichloromethane, chloroform, carbon tetrachloride, chlorobenzene, and dichlorobenzene; ether solvents such as diethyl ether, tetrahydrofuran, and 4-methyltetrahydropyran; amine solvents that can also serve as bases such as triethylamine and pyridine; and aprotic organic solvents such as dimethyl sulfoxide, acetonitrile, and N,N-dimethylformamide. As the solvent, it is preferable to use a solvent that can dissolve both the raw material polyalkylene diol and the silylated product.

[0041] The reaction of the general formula (4) can be carried out by a procedure known as a silylation reaction. For example, after adding and mixing a base to a solution of a polyalkylene diol, the silylation reaction can be carried out by adding and mixing a silylating agent to the reaction mixture. The addition and mixing of the silylating agent can be carried out, for example, by dropping the silylating agent or its solution into a mixture of a polyalkylene diol solution at a low temperature (e.g., 0 °C) and a base. After adding the silylating agent to the reaction mixture, the silylation reaction can be allowed to proceed by stirring the reaction mixture at a low temperature or at room temperature for a certain period of time (e.g., 0.01 to 100 hours). The reactivity of the silylating agent depends on the structure of the polyalkylene diol and / or the substituents R 2 ~R 4 on the silicon atom. When the progress of the reaction is slow at room temperature, it is preferable to carry out the reaction at a higher temperature (e.g., under reflux conditions of the solvent).

[0042] In the reaction of the general formula (4), for example, 1 to 10 mol of a base and 0.5 to 2 mol, preferably 1.0 to 1.2 mol, of a silylating agent can be used per 1 mol of the hydroxy group of the polyalkylene diol. When a silylating agent less than the equivalent amount of the hydroxy group is used, a partially silylated product in which only the hydroxy group at one end of the polyalkylene diol is silylated is formed together with a completely silylated product in which the hydroxy groups at both ends of the polyalkylene diol are silylated. Depending on the reactivity of the silylation reaction, a partially silylated product may be formed together with the completely silylated product, but it is also possible to use the mixture containing the completely silylated product and the partially silylated product as it is.

[0043] The post-treatment after the completion of the reaction may be carried out in the same manner as in the silylation reaction of a general alcohol. The unreacted silylating agent can be quenched by water treatment or alcohol treatment. The silylation product has improved hydrophobicity due to the conversion of the terminal hydroxy group to a silyl ether. Therefore, by washing the reaction mixture with water, salts in the reaction mixture (e.g., when the base is triethylamine and the leaving group X of the silylating agent 1When it is a -Cl group, it is triethylamine hydrochloride.) And polyalkylene diols with incomplete silylation (that is, unreacted polyalkylene diols that have not been silylated, and partial silylation products in which only the hydroxy group at one end of the polyalkylene diol is silylated.) are removed to obtain an organic solvent solution of the silylation product. However, when the proportion of polyethylene oxide repeating units in the repeating unit of the raw material polyalkylene diol is high (that is, when the proportion of ethane-1,2-diyl groups in the alkylene group R 1 is high), when the reaction mixture is mixed with water, the silylation product may transfer from the organic layer to the aqueous layer, and the yield may decrease. In such a case, it is possible to recover the silylation product by a post-treatment that does not use water. Specifically, after the reaction is carried out using a solvent having a certain degree of polarity (such as toluene, etc.) to dissolve the raw material polyalkylene diol, if necessary, the remaining unreacted silylating agent is treated with an alcohol (such as methanol or ethanol, etc.), and a hydrophobic solvent (such as hydrocarbon solvents such as hexane, petroleum ether, cyclohexane, benzene, and further toluene, etc.) is added to the slurry-like reaction mixture, and the precipitated salt is removed by filtration to obtain an organic solvent solution of the silylation product. The organic solvent can be distilled off from the obtained organic solvent solution of the silylation product (for example, under reduced pressure conditions) to separate the silylation product.

[0044] (Physical properties) In the polyalkylene diol modified product of the present invention, since the terminal hydroxy group is converted to a silyl ether, it has a better viscosity index than the corresponding polyalkylene diol that has not been silylated, and thus can be preferably used as a lubricating base material with a high viscosity index.

[0045] Moreover, since the polyalkylene diol modified product of the present invention has a higher polarity than conventional mineral oil-based base oils, poly-α-olefin base oils, and silicone oil (polydimethylsiloxane), which is a conventional general-purpose high-viscosity-index lubricating base material, it is advantageous in the solubility of polar additives. Further, while the carbonyl carbon of the ester bond in conventional ester-based synthetic base oils is susceptible to nucleophilic attack, the ether bond and silyl ether bond of the polyalkylene diol modified product of the present invention are more resistant to nucleophilic attack under basic conditions than the ester bond. Therefore, according to the polyalkylene diol modified product of the present invention, it may be possible to combine with additives that were difficult to use in combination with conventional ester-based synthetic base oils due to their nucleophilicity.

[0046] The polyalkylene diol modified product of the present invention has a higher viscosity index than the corresponding polyalkylene diol. Generally, the higher the bulky silyl group, the higher the chemical stability of the silyl ether bond. Therefore, the silyl group can be selected in consideration of the stability and viscosity index required for the intended application. The specific viscosity index of the polyalkylene diol modified product can be, for example, 100 to 300, and in one embodiment, 150 to 300.

[0047] As described above, the polyalkylene diol modified product of the present invention can be produced by silylating the hydroxy group of the polyalkylene diol. The kinematic viscosity of the polyalkylene diol modified product of the present invention is the kinematic viscosity of the corresponding polyalkylene diol and the silyl group (Q in the general formula (1) 1 and Q 2) may vary depending on . The higher the kinematic viscosity of the corresponding polyalkylene diol, the higher the kinematic viscosity of the resulting polyalkylene diol-modified product tends to be. Also, if the corresponding polyalkylene diols are the same, the larger the silyl group, the higher the kinematic viscosity of the polyalkylene diol-modified product tends to be. In order to obtain a polyalkylene diol-modified product having a desired kinematic viscosity and viscosity index, a mixture of two or more polyalkylene diols may be used as the raw material polyalkylene diol. Also, in order to obtain a polyalkylene diol-modified product having a desired kinematic viscosity and viscosity index, two or more polyalkylene diol-modified products may be mixed.

[0048] <2. Lubricating oil base oil> The lubricating oil base oil according to the second aspect of the present invention (hereinafter sometimes simply referred to as "lubricating oil base oil") contains the polyalkylene diol-modified product according to the first aspect of the present invention (hereinafter sometimes referred to as "(a) component"). The lubricating oil base oil may contain one kind of polyalkylene diol-modified product alone, or may contain two or more kinds of polyalkylene diol-modified products. In one embodiment, the lubricating oil base oil consists of one or more polyalkylene diol-modified products. The lubricating oil base oil may further contain, as an impurity, an incompletely silylated polyalkylene diol that was not removed during the purification process of the polyalkylene diol-modified product. Examples of the incompletely silylated polyalkylene diol include an unsilylated polyalkylene diol and a polyalkylene diol in which only the hydroxy group at one end is silylated (partially silylated product). In one embodiment, the content of these incompletely silylated polyalkylene diols may be, for example, less than 50 parts by mass, or less than 30 parts by mass, per 100 parts by mass of the polyalkylene diol-modified product. The content of the incompletely silylated polyalkylene diol can be measured by 13 13C NMR under the conditions described later. In one embodiment, the content of the unsilylated hydroxy group of the polyalkylene diol may be, for example, less than 0.5 mol, or less than 0.3 mol, per 1 mol of the silyl group of the polyalkylene diol-modified product. In one embodiment, the lubricating base oil may further contain one or more base oil components other than the polyalkylene diol-modified product. As such other base oil components, mineral oil-based base oils, or conventional synthetic base oils, or combinations thereof can be used.

[0049] In one embodiment, examples of mineral oil-based base oils include lubricating oil fractions obtained by atmospheric distillation and / or vacuum distillation of crude oil, which are purified by one or a combination of two or more selected from purification processes such as solvent dewaxing, solvent extraction, hydrocracking, hydroisomerization, solvent deasphalting, catalytic deasphalting, solvent refining, hydrorefining, chemical washing, and clay treatment, paraffinic mineral oils, normal paraffin-based base oils, isoparaffin-based base oils, naphthenic base oils, and mixtures thereof.

[0050] In one embodiment, preferred examples of mineral oil-based base oils include base oils obtained by purifying any of the following (1) to (8) as a feedstock oil and the feedstock oil and / or the lubricating oil fraction recovered from the feedstock oil. (1) Distillate oil obtained by atmospheric distillation of paraffin-based crude oil and / or mixed-base crude oil (2) Distillate oil (WVGO) obtained by vacuum distillation of atmospheric distillation residue oil of paraffin-based crude oil and / or mixed-base crude oil (3) Wax (such as slack wax) obtained by the lubricating oil deasphalting process and / or synthetic wax (such as FT wax such as GTL wax) obtained by the Fischer-Tropsch (FT) process (such as the Gas-to-Liquid (GTL) process), synthetic wax obtained by oligomerization of ethylene (4) Mild hydrocracking treated oil of the feedstock oil (1), (2), or (3), or a mixture thereof (5) Mixed oil of two or more selected from the feedstock oils (1) to (4) (6) Dewaxed oil (DAO) of the feedstock oil (1), (2), (3), (4), or (5) (7) Mild hydrocracking treated oil (MHC) of the feedstock oil (6) (8) Mixed oil of two or more selected from the feedstock oils (1) to (7)

[0051] Particularly preferred examples of the mineral oil base oil include the following base oils (9) or (10) obtained by performing a predetermined treatment on the feedstock oil selected from the above (1) to (8) or the lubricating oil fraction recovered from the feedstock oil. (9) Hydrocrack the feedstock oil selected from the above (1) to (8) or the lubricating oil fraction recovered from the feedstock oil, and perform dewaxing treatment such as solvent dewaxing or catalytic dewaxing on the product or the lubricating oil fraction recovered from the product by distillation or the like, or a hydrocracked base oil obtained by distilling after the dewaxing treatment. (10) Hydroisomerize the feedstock oil selected from the above (1) to (8) or the lubricating oil fraction recovered from the feedstock oil, and perform dewaxing treatment such as solvent dewaxing or catalytic dewaxing on the product or the lubricating oil fraction recovered from the product by distillation or the like, or a hydroisomerized base oil obtained by distilling after the dewaxing treatment. As the dewaxing step, a base oil produced through a catalytic dewaxing step is preferred.

[0052] In addition, when obtaining the mineral oil base oil of the above (9) or (10), a solvent refining treatment and / or a hydrofinishing treatment step may be further performed at an appropriate stage as necessary.

[0053] In one embodiment, as the mineral oil base oil, Group I base oil of the API base oil classification (hereinafter sometimes referred to as "API Group I base oil"), Group II base oil (hereinafter sometimes referred to as "API Group II base oil"), or Group III base oil (hereinafter sometimes referred to as "API Group III base oil"), or a combination thereof can be used. The API base oil classification is as described above. API Group I base oil is usually produced through a solvent refining process, and API Group II base oil and Group III base oil are usually produced through a hydrocracking process. In this specification, the viscosity index means the viscosity index measured in accordance with JIS K 2283-2000. Also, in this specification, the "sulfur content in the lubricating oil base oil" is measured in accordance with JIS K 2541-2003. Further, in this specification, the "saturation content in the lubricating oil base oil" means the value measured in accordance with ASTM D 2007-93.

[0054] As the conventional synthetic base oil, API Group IV base oil (polyalphaolefin base oil, hereinafter sometimes referred to as "API Group IV base oil"), or conventional API Group V base oil (hereinafter sometimes referred to as "API Group V base oil"), or a combination thereof can be used.

[0055] The content of component (a) in the lubricating oil base oil is not particularly limited, but can be, for example, 1 to 100% by mass, or 5 to 100% by mass, or 10 to 100% by mass, or 20 to 100% by mass, or 50 to 100% by mass, or 80 to 100% by mass based on the total amount of the lubricating oil base oil.

[0056] <3. Lubricating oil composition> The lubricating oil composition according to the third aspect of the present invention (hereinafter sometimes simply referred to as "lubricating oil composition") contains the lubricating base oil according to the second aspect of the present invention (hereinafter sometimes referred to as "(A) component"). In one embodiment, the lubricating oil composition may consist of the (A) component. In another embodiment, the lubricating oil composition may contain the (A) component and one or more additives.

[0057] The content of the (A) component in the lubricating oil composition is not particularly limited, but may be, for example, 60 to 100% by mass, or 60 to 99% by mass based on the total amount of the composition.

[0058] As the additive, an additive known in the field of lubricating oils can be used. Examples of such additives include (B) antioxidant, (C) ashless dispersant, (D) metal detergent, (E) friction modifier, (F) antiwear agent or extreme pressure agent, (G) viscosity index improver or pour point depressant, (H) corrosion inhibitor, (I) rust preventive, (J) metal deactivator, (K) demulsifier, (L) antifoaming agent, and (M) colorant.

[0059] Examples of the (B) antioxidant (hereinafter sometimes referred to as "(B) component") include aromatic amine-based antioxidants, hindered amine-based antioxidants, and phenolic antioxidants.

[0060] Examples of the aromatic amine-based antioxidant include primary aromatic amine compounds such as alkylated α-naphthylamine; and secondary aromatic amine compounds such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, phenyl-β-naphthylamine, and alkylated phenyl-β-naphthylamine.

[0061] Examples of the hindered amine-based antioxidant include compounds having a 2,2,6,6-tetraalkylpiperidine skeleton (2,2,6,6-tetraalkylpiperidine derivatives). As the 2,2,6,6-tetraalkylpiperidine derivative, a 2,2,6,6-tetraalkylpiperidine derivative having a substituent at the 4-position is preferable. Further, two 2,2,6,6-tetraalkylpiperidine skeletons may be bonded via the substituents at the respective 4-positions. The N-position of the 2,2,6,6-tetraalkylpiperidine skeleton may be unsubstituted, or an alkyl group having 1 to 4 carbon atoms may be substituted at the N-position. The 2,2,6,6-tetraalkylpiperidine skeleton is preferably a 2,2,6,6-tetramethylpiperidine skeleton.

[0062] Examples of phenolic antioxidants include 4,4'-methylenebis(2,6-di-tert-butylphenol); 4,4'-bis(2,6-di-tert-butylphenol); 4,4'-bis(2-methyl-6-tert-butylphenol); 2,2'-methylenebis(4-ethyl-6-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-tert-butylphenol); 4,4'-butylidenebis(3-methyl-6-tert-butylphenol); 4,4'-isopropylidenebis(2,6-di-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-nonylphenol); 2,2'-isobutylidenebis(4,6-dimethylphenol); 2,2'-methylenebis(4-methyl-6-cyclohexylphenol); 2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4-(N,N'-dimethylaminomethyl)phenol; 4,4'-thiobis(2-methyl-6-tert-butylphenol); 4,4'-thiobis(3-methyl-6-tert-butylphenol); 2,2'-thiobis(4-methyl-6-tert-butylphenol); bis(3-methyl-4-hydroxy-5-tert-butylbenzyl)sulfide; bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide; 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid esters; 3-methyl-5-tert-butyl-4-hydroxyphenol fatty acid esters, and other hindered phenol compounds and bisphenol compounds can be mentioned.

[0063] When the lubricating oil composition contains the component (B), its content may be, for example, 0.01 to 5.0% by mass, or 0.1 to 5.0% by mass based on the total amount of the composition. From the viewpoint of suppressing the autoxidation of the polyalkylene diol-modified product ((a) component), it is preferable that the lubricating oil composition contains at least the component (B).

[0064] (C) As the ashless dispersant, known ashless dispersants such as succinimide - type ashless dispersants can be used. Examples of ashless dispersants include polybutenyl succinimide having a polybutenyl group with a number - average molecular weight of 900 to 3,500, polybutenyl benzylamine, polybutenylamine, and their derivatives (such as boric acid - modified products, etc.). When the lubricating oil composition contains an ashless dispersant, its content can be, for example, 0.01 to 20% by mass, or 0.1 to 10% by mass based on the total amount of the composition.

[0065] (D) As the metal - based detergent, metal - based detergents known in the lubricating oil field can be used. Generally, in the lubricating oil field, as the metal - based detergent, an organic acid metal salt capable of forming micelles in the base oil (such as an alkali or alkaline - earth metal alkyl salicylate, an alkali or alkaline - earth metal alkylbenzene sulfonate, and an alkali or alkaline - earth metal alkylphenate, etc.), or a mixture of the organic acid metal salt and a basic metal salt (such as a hydroxide, carbonate, borate, etc. of the alkali or alkaline - earth metal constituting the organic acid metal salt) is used. As the metal, an alkaline - earth metal is preferred, and as the alkaline - earth metal, Ca and / or Mg are preferred. When the lubricating oil composition contains a metal - based detergent, its content can be, for example, 0.001 to 5.0% by mass in terms of the amount of metal element based on the total amount of the composition.

[0066] (E) As the friction modifier, friction modifiers known in the lubricating oil field can be used. Examples thereof include oil - type friction modifiers; organic molybdenum compounds; organic boron compounds such as alkyl mercaptyl borate; graphite; molybdenum disulfide; antimony sulfide; boron compounds; polytetrafluoroethylene, etc.

[0067] When the lubricating oil composition contains a friction modifier, its content can be, for example, 0.05 to 5.0% by mass based on the total amount of the composition.

[0068] (F) As the antiwear agent or extreme pressure agent, an antiwear agent or extreme pressure agent known in the lubricating oil field can be used. Examples thereof include sulfur-based additives such as metal dithiocarbamates (Zn salts, Pb salts, Sb salts, etc.), disulfides, sulfurized fats and oils, sulfurized olefins, sulfurized mineral oils, dialkyl polysulfides, diarylalkyl polysulfides, diaryl polysulfides, etc.; metal dithiophosphates (Zn salts, Pb salts, Sb salts, Mo salts, etc.), phosphate esters, phosphite esters, amine salts of partial phosphate esters, metal salts of partial phosphate esters (Zn salts, etc.), complete esters and partial esters of (monothio- or dithio- or trithiophosphoric acid) and metal salts and amine salts of partial esters, complete esters and partial esters of (monothio- or dithio-) phosphorous acid and metal salts and amine salts of partial esters, etc., phosphorus-based and phosphorus-sulfur-based additives; and naphthenic acid metal salts (Pb salts, etc.), fatty acid metal salts (Pb salts, etc.), boron compounds, etc. When the lubricating oil composition contains an antiwear agent or extreme pressure agent, its content may be, for example, 0.05 to 5% by mass based on the total amount of the composition.

[0069] (G) As the viscosity index improver or pour point depressant, a viscosity index improver or pour point depressant known in the lubricating oil field can be used. Examples of the viscosity index improver include dispersed or non-dispersed polyalkyl (meth) acrylates; non-dispersed or dispersed ethylene-α-olefin copolymers and hydrogenated products thereof; polyisobutylene and hydrogenated products thereof; hydrogenated products of styrene-diene copolymers; styrene-maleic anhydride ester copolymers; and polyalkylstyrenes, etc. Examples of the pour point depressant include polymethacrylate-based polymers, ethylene vinyl acetate, etc. When the lubricating oil composition contains a viscosity index improver or pour point depressant, its content may be, for example, 0.01 to 20% by mass based on the total amount of the composition.

[0070] (H) As the corrosion inhibitor, corrosion inhibitors known in the lubricating oil field can be used. Examples thereof include benzotriazole-based compounds, tolyltriazole-based compounds, thiadiazole-based compounds, and imidazole-based compounds. When the lubricating oil composition contains a corrosion inhibitor, its content can be, for example, 0.005 to 5% by mass based on the total amount of the composition.

[0071] (I) As the rust inhibitor, rust inhibitors known in the lubricating oil field can be used. Examples thereof include petroleum sulfonates, alkylbenzene sulfonates, dinonylnaphthalene sulfonates, alkyl sulfonates, fatty acids, alkenyl succinic acid half esters, fatty acid soaps, polyhydric alcohol fatty acid esters, fatty acid amines, oxidized paraffins, alkyl polyoxyethylene ethers, and the like. When the lubricating oil composition contains a rust inhibitor, its content can be, for example, 0.005 to 5% by mass based on the total amount of the composition.

[0072] (J) As the metal deactivator, metal deactivators known in the lubricating oil field can be used. Examples thereof include imidazoline, pyrimidine derivatives, alkyl thiadiazoles, mercaptobenzothiazole, benzotriazole and its derivatives, 1,3,4-thiadiazole polysulfides, 1,3,4-thiadiazolyl-2,5-bisdialkyldithiocarbamates, 2-(alkyldithio)benzimidazole, and β-(o-carboxybenzylthio)propionitrile. When the lubricating oil composition contains a metal deactivator, its content can be, for example, 0.005 to 1% by mass based on the total amount of the composition.

[0073] (K) As the demulsifier, known demulsifiers such as polyalkylene glycol-based nonionic surfactants can be used. When the lubricating oil composition contains a demulsifier, its content can be, for example, 0.005 to 5% by mass based on the total amount of the composition.

[0074] (L) As the antifoaming agent, an antifoaming agent known in the lubricating oil field can be used. Examples thereof include silicone, fluorosilicone, and fluoroalkyl ether. When the lubricating oil composition contains an antifoaming agent, its content can be, for example, 0.0001 to 0.1% by mass based on the total amount of the composition.

[0075] (M) As the coloring agent, a known coloring agent such as an azo compound can be used.

Examples

[0076] Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples. However, the present invention is not limited to these Examples. <Examples> (Measurement of molecular weight and molecular weight distribution) In the following Examples, the number average molecular weight (Mn) of the sample was measured by gel permeation chromatography (GPC) as the number average molecular weight in terms of standard polystyrene. The measurement conditions of GPC are as follows. Apparatus: ACQUITY (registered trademark) APC UV RI system manufactured by Waters Corporation Columns: In order from the upstream side, one ACQUITY (registered trademark) APC XT125A (gel particle size 2.5 μm, column size (inner diameter × length) 4.6 mm × 150 mm) manufactured by Waters Corporation and two ACQUITY (registered trademark) APC XT45A (gel particle size 1.7 μm, column size (inner diameter × length) 4.6 mm × 150 mm) manufactured by Waters Corporation are connected in series Column temperature: 40 °C Sample solution: Tetrahydrofuran (THF) solution with a sample concentration of 1.0% by mass Eluent: THF Solution injection volume: 20.0 μL Flow rate: 0.7 mL / min Detector: Differential refractive index detector Reference substance: 10 points of standard polystyrene (Agilent EasiCal® PS-1 manufactured by Agilent Technologies) (molecular weights: 30230, 9590, 2970, 890, 786, 682, 578, 474, 370, 266)

[0077] (Measurement of kinematic viscosity and viscosity index) In the following examples, the kinematic viscosity of the sample was measured in accordance with JIS K 2283-2000 using an automatic viscometer (trade name "CAV-2000", manufactured by Cannon Instrument) as the measuring device. Also, the viscosity index of the sample was determined in accordance with JIS K 2283-2000 based on the measured values of kinematic viscosity at 40 °C and 100 °C.

[0078] ( Reference Example 1) The hydroxy group of polypropylene glycol (PPG) was silylated with a trimethylsilyl (TMS) group by the following procedure to produce a corresponding polyalkylene diol modified product (TMS-modified PPG) in which the polyalkylene diol has the form where R in the general formula (1) 1 is a propane-1,2-diyl group, and Q 1 and Q 2 are TMS groups. 10.00 g of PPG (Mn = 200) was weighed into a 200 mL eggplant flask, and 50 mL of dehydrated THF was added thereto. 200 mmol of triethylamine (TEA) was added thereto, and while stirring vigorously, 101 mmol of trimethylchlorosilane (TMS-Cl) was added dropwise over 1 hour under ice cooling (0 °C), and the slurry-like reaction mixture was further stirred for 1 hour. After completion of the reaction, 20 mL of water was slowly added to dissolve the white insoluble matter, THF was distilled off with an evaporator, and the organic matter was extracted twice with 50 mL of hexane from the residue. The hexane layer was washed with saturated brine, and the washed hexane layer was dried over magnesium sulfate. Hexane was distilled off under reduced pressure from the hexane solution from which the desiccant had been removed by filtration to obtain TMS-modified PPG. The kinematic viscosity of the obtained modified product was measured. The results are shown in Table 1.

[0079] (Comparative Example 1) For the PPG used as a raw material in Example 1, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 1.

[0080] (Example 2) According to the following procedure, a polyalkylene diol-modified product (TMS-modified PPG) in which the corresponding polyalkylene diol is PPG and Q 1 and Q 2 are TMS groups was produced. Using 20.00 g of PPG (Mn = 750), which has a different number average molecular weight from the PPG used in Example 1, as the polyalkylene diol, changing the amount of TEA used to 150 mmol, and changing the amount of TMS-Cl used to 68 mmol, TMS-modified PPG was synthesized by the same procedure as in Example 1. The kinematic viscosities of the obtained modified products are shown in Table 1.

[0081] (Comparative Example 2) For the PPG used as a raw material in Example 2, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 1.

[0082] (Example 3) According to the following procedure, a polyalkylene diol-modified product (TMS-modified PPG) in which the corresponding polyalkylene diol is PPG and Q 1 and Q 2 are TMS groups was produced. Using 9.82 g of PPG (Mn = 1120), which has a different number average molecular weight from the PPG used in Example 1, as the polyalkylene diol, changing the amount of TEA used to 60 mmol, and changing the amount of TMS-Cl used to 22 mmol, TMS-modified PPG was synthesized by the same procedure as in Example 1. The kinematic viscosities of the obtained modified products are shown in Table 1.

[0083] (Comparative Example 3) For the PPG used as a raw material in Example 3, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 1.

[0084] ( Reference Example 4 According to the following procedure, a polyalkylene diol-modified product (TMS-modified PPG) in which the corresponding polyalkylene diol is PPG and Q 1 and Q 2 are TMS groups was produced. 20.00 g of PPG (Mn = 2110) with a different number average molecular weight from the PPG used in Example 1 was used as the polyalkylene diol. Except that the amount of TEA used was changed to 50 mmol and the amount of TMS-Cl used was changed to 24 mmol, TMS-modified PPG was synthesized by the same procedure as in Example 1. The density and kinematic viscosity of the obtained modified product are shown in Table 1.

[0085] (Comparative Example 4) For the PPG used as a raw material in Example 4, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 1.

[0086] (Example 5) According to the following procedure, a polyalkylene diol-modified product (DMPS-modified PPG) in which the corresponding polyalkylene diol is PPG and Q 1 and Q 2 are dimethylphenyl groups (DMPS groups) was produced. 19.56 g of the PPG used in Example 3 was weighed into a 200 mL eggplant flask, and 50 mL of dehydrated hexane was added thereto. TEA (46 mmol) was added here, and further dimethylphenylchlorosilane (DMPS-Cl, 38 mmol) was slowly added, and the reaction mixture was heated to reflux for 3 hours. After the reaction mixture was cooled to room temperature, water (20 mL) was added to dissolve the white precipitate. The hexane layer was separated, and the aqueous layer was extracted twice with 50 mL of toluene. The organic layers were mixed, washed with saturated brine, and the washed organic layer was dried over anhydrous magnesium sulfate. The desiccant was separated by filtration, and the solvent was distilled off under reduced pressure to obtain DMPS-modified PPG. The kinematic viscosity of the obtained modified product is shown in Table 2.

[0087] (Example 6) According to the following procedure, the corresponding polyalkylene diol is PPG, and in the general formula (1), Q 1 and Q 2 is a tert-butyldimethylsilyl group (TBDMS group), and a polyalkylene diol modified product (TBDMS-modified PPG) was produced. Sodium hydride (NaH, 60% in Oil, 40 mmol) was weighed into a 200 mL eggplant flask, 10 mL of dehydrated hexane was added, stirred, allowed to stand, and the supernatant was removed with a syringe. This hexane washing operation was repeated 3 times, and 100 mL of dehydrated toluene was added to the washed NaH. To this, PPG (11.12 g) used in Example 3 was slowly added while paying attention to foaming. Further, tert-butyldimethylchlorosilane (TBDMS-Cl, 22 mmol) was added, and the mixture was stirred at 80 °C for 2 hours. The reaction mixture was cooled to room temperature, 20 mL of water was added to dissolve the white precipitate. The toluene layer was separated, and the aqueous layer was extracted twice with 50 mL of toluene. The organic layers were mixed and washed with saturated brine. The washed toluene solution was dried over anhydrous magnesium sulfate, the desiccant was removed by filtration, and toluene was distilled off under reduced pressure to obtain TBDMS-modified PPG. The kinematic viscosity of the obtained modified product is shown in Table 2.

[0088] (Example 7) According to the following procedure, the corresponding polyalkylene diol is PPG, and in the general formula (1), Q 1 and Q 2 is a triisopropylsilyl group (TIPS group), and a polyalkylene diol modified product (TIPS-modified PPG) was produced. The amount of PPG used in Example 3 was 10.48 g, the amount of toluene used was 200 mL, and TIPS-modified PPG was obtained by the same procedure as in Example 6 except that triisopropylchlorosilane (TIPS-Cl, 20 mmol) was used instead of TBDMS-Cl. The kinematic viscosity of the obtained modified product is shown in Table 2.

[0089] ( Reference Example 8) According to the following procedure, the corresponding polyalkylene diol is PPG, and in the general formula (1), Q 1 and Q 2 are tert-butyldiphenylsilyl groups (TBDPS groups), and a polyalkylene diol modified product (TBDPS-modified PPG) was produced. The amount of PPG used in Example 3 was 16.01 g, the amount of toluene used was 200 mL, and TBDPS-modified PPG was obtained by the same procedure as in Example 6, except that tert-butyldiphenylchlorosilane (TBDPS-Cl, 30 mmol) was used instead of TBDMS-Cl. The kinematic viscosity of the obtained modified product is shown in Table 2.

[0090] (Example 9) According to the following procedure, the corresponding polyalkylene diol is polyethylene glycol (PEG), and in the general formula (1), Q 1 and Q 2 are TMS groups, and a polyalkylene diol modified product (TMS-modified PEG) was produced. 11.19 g of PEG (Mn = 810) was weighed into a 200 mL eggplant flask, and 50 mL of dehydrated toluene was added thereto. TEA (70 mmol) was added thereto, and while stirring vigorously, TMS-Cl (48 mmol) was added dropwise over 1 hour under ice cooling (0 °C), and the slurry-like reaction mixture was further stirred for 1 hour. The reaction mixture was filtered under reduced pressure, and the soluble component was extracted from the cake with 300 mL of hexane as it was and mixed with the previous filtrate (toluene solution). A white precipitate was formed again, and filtration under reduced pressure was performed again. The solvent was distilled off from the filtrate under reduced pressure to obtain TMS-modified PEG. Its kinematic viscosity is shown in Table 3.

[0091] (Comparative Example 5) For the PEG used as a raw material in Example 9, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 3.

[0092] (Example 10) According to the following procedure, the corresponding polyalkylene diol is a propylene oxide (PO, 90% by mass)-ethylene oxide (EO, 10% by mass) copolymer, and Q in the general formula (1) 1 and Q 2 is a polyalkylene diol modified product in the form of a TMS group. 21.07 g of polyalkylene diol (PO (90% by mass)-EO (10% by mass) copolymer (Mn = 1210)) was dissolved in THF (50 mL), and TEA (70 mmol) was added thereto. While stirring vigorously under ice cooling, TMS-Cl (50 mmol) was added dropwise to this solution over 1 hour. Stirring was continued for 1 hour after the addition was complete. 20 mL of water was added to this reaction solution, and THF was distilled off under reduced pressure. The organic matter was extracted twice with 50 mL of hexane from the residue. The obtained hexane solution was washed with saturated brine and dried over anhydrous magnesium sulfate. The desiccant was removed by filtration, and hexane was distilled off under reduced pressure to obtain a TMS-modified product. The kinematic viscosity of the obtained modified product was measured. The results are shown in Table 4.

[0093] (Comparative Example 6) The kinematic viscosities of the PO-EO copolymer (PO:EO copolymerization ratio = 90:10 w / w) used as a raw material in Example 10 were measured at 40 °C and 100 °C. The results are shown in Table 4.

[0094] (Example 11) According to the following procedure, the corresponding polyalkylene diol is a butene oxide (BO) polymer, and Q in the general formula (1) 1 and Q 2 is a polyalkylene diol modified product in the form of a TMS group. A TMS-modified product was obtained in the same procedure as in Example 10, except that 19.60 g of a BO polymer (Mn = 910) was used instead of the PO-EO copolymer. The kinematic viscosity of the obtained TMS-modified product is shown in Table 4.

[0095] (Comparative Example 7) The kinematic viscosities of the BO polymer used as a raw material in Example 11 were measured at 40 °C and 100 °C. The results are shown in Table 4.

[0096] ( Reference Example 12) By the following procedure, a polyalkylene diol-modified product in which the corresponding polyalkylene diol is a BO polymer having a number average molecular weight different from that used in Example 11 and Q in the general formula (1) 1 and Q 2 are in the form of TMS groups was produced. As the polyalkylene diol, 20.50 g of a BO polymer (Mn = 570) having a number average molecular weight different from that used in Example 11 was used. A TMS-modified product was obtained by the same procedure as in Example 10, except that the amount of TEA used was 100 mmol and the amount of TMS-Cl used was 70 mmol. The kinematic viscosity of the obtained TMS-modified product is shown in Table 4.

[0097] (Comparative Example 8) For the BO polymer having a number average molecular weight of 570 used as a raw material in Example 12, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 4.

[0098] (Example 13) By the following procedure, a polyalkylene diol-modified product in which the corresponding polyalkylene diol is a THF (45 mass%)-EO (55 mass%) copolymer and Q in the general formula (1) 1 and Q 2 are in the form of TMS groups was produced. As the polyalkylene diol, 19.29 g of a THF (45 mass%)-EO (55 mass%) copolymer (Mn = 1760) was used. A TMS-modified product was obtained by the same procedure as in Example 10, except that the amount of TEA used was 150 mmol and the amount of TMS-Cl used was 103 mmol. The kinematic viscosity of the obtained TMS-modified product is shown in Table 4.

[0099] (Comparative Example 9) For the THF-EO copolymer (THF:EO copolymerization ratio = 45:55 w / w) used as a raw material in Example 13, the kinematic viscosities at 40 °C and 100 °C were measured. The results are shown in Table 4.

[0100] ( Reference Example 14) According to the following procedure, the corresponding polyalkylene diol is a THF (60% by mass)-EO (40% by mass) copolymer, and in the general formula (1), Q 1 and Q 2 are in the form of TMS groups, and a modified polyalkylene diol was produced. Using 20.36 g of a THF (60% by mass)-EO (40% by mass) copolymer as the polyalkylene diol, with the amount of TEA used being 70 mmol and the amount of TMS-Cl used being 50 mmol, a TMS-modified product was obtained by the same procedure as in Example 10. The kinematic viscosity of the obtained TMS-modified product is shown in Table 4.

[0101] (Comparative Example 10) For the THF-EO copolymer (THF:EO copolymerization ratio = 60:40 w / w) used as a raw material in Example 14, the kinematic viscosities at 40°C and 100°C were measured. The results are shown in Table 4.

[0102] [Table 1]

[0103] [Table 2]

[0104] [Table 3]

[0105] [Table 4]

Claims

【Claim 1】 A lubricating oil composition containing a lubricating base oil containing a polyalkylene diol-modified product, wherein the lubricating base oil is represented by the following general formula (1), the number average molecular weight of the corresponding polyalkylene diol is 750 to 1760, and the viscosity index of the polyalkylene diol-modified product is 183 or more and 300 or less (however, excluding refrigeration machine oils). 【Chemical Formula 1】 (In general formula (1), R １ is an ethane-1,2-diyl group, a propane-1,2-diyl group, a butane-1,2-diyl group, a butane-2,3-diyl group, or a butane-1,4-diyl group, or a combination thereof, and Q １ and Q ２ are one or more silyl groups selected from a trimethylsilyl group, a triisopropylsilyl group, a tert-butyldimethylsilyl group, and a dimethylphenylsilyl group.)

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