JPH1180331A - Aliphatic polyester for lubricating base oil and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-polymerized aliphatic polyester which is excellent in low-temperature fluidity, has a high viscosity index and an appropriate level of kinematic viscosity, and is used for a lubricating base oil. SOLUTION: A saturated aliphatic dicarboxylic acid having a main chain having 4 to 10 carbon atoms or a derivative thereof is condensed with at least two kinds of diols selected from saturated aliphatic diols having a main chain having 4 to 8 carbon atoms. Kinematic viscosity at 100 ° C.
An aliphatic polyester for a lubricating base oil, which is 50 cSt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester polymer for a lubricating base oil having excellent low-temperature fluidity and a high viscosity index.

[0002]

2. Description of the Related Art Conventionally, ester-based synthetic lubricating oils have a wide operating temperature range, excellent heat and oxidation stability, a high flash point,
Although used as a lubricating oil having a small amount of evaporation and good lubricity, a lubricating base oil having a higher viscosity index and excellent biodegradability has been desired. Among them, ester compounds, which are condensates of dicarboxylic acids and diols, have been developed for lubricating base oils, additives and refrigerator oils. For example, JP-A-47-9046 describes the use of a polyester obtained by condensing a diol with a saturated branched dicarboxylic acid or a derivative thereof or an anhydride thereof as a lubricating oil. In addition, WO
JP-A-91-07479 discloses a polyester obtained by a condensation reaction of a dicarboxylic acid such as malonic acid and a diol such as neopentyl glycol as a lubricating oil for refrigerator oil. Further, JP-A-3-200896 describes that a reactant of a diol and a dicarboxylic acid is used as a refrigerating machine oil for a chlorine-free Freon refrigerant. However, none of these lubricating oils has an excellent balance between low-temperature fluidity and viscosity index.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-polymerized aliphatic polyester used for a lubricating base oil having excellent low-temperature fluidity, a high viscosity index and an appropriate level of kinematic viscosity, and a method for producing the same. To provide.

[0004]

Means for Solving the Problems The inventors of the present invention have found that, in an aliphatic polyester obtained by condensing a saturated aliphatic dicarboxylic acid or a derivative thereof with a saturated aliphatic diol, the number of carbon atoms in the main chain of a specific dicarboxylic acid or An aliphatic polyester obtained by performing a condensation reaction using the ester and at least two kinds of diols having a specific number of carbon atoms in the main chain is excellent in low-temperature fluidity and has a high viscosity index and a low molecular weight ester copolymer. The present invention was found to have a performance suitable for a lubricating base oil and reached the present invention.

That is, according to the present invention, the number of carbon atoms in the main chain is 4 to 4.
100 obtained by condensing 10 saturated aliphatic dicarboxylic acids or derivatives thereof with at least two kinds of diols selected from saturated aliphatic diols having 4 to 8 carbon atoms in the main chain.
An aliphatic polyester for a lubricating base oil having a kinematic viscosity at 3 ° C. of 3 to 50 cSt, and a method for producing the same comprises a saturated aliphatic dicarboxylic acid having a main chain having 4 to 10 carbon atoms or a derivative thereof and a main chain carbon. The use of at least two kinds of diols selected from among saturated aliphatic diols having a number of 4 to 8 using a 3 to 15-fold molar excess of a saturated aliphatic dicarboxylic acid or a derivative thereof with respect to a saturated aliphatic diol, The method is characterized in that a polycondensation reaction is performed at 140 to 200 ° C for 1 to 5 hours in the presence of a compound catalyst.

Preferred embodiments of the present invention are as follows. The above lubricating oil aliphatic polyester, wherein the saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in the main chain or a derivative thereof is a saturated aliphatic dicarboxylic acid diester having 4 to 10 carbon atoms in the main chain. The above-mentioned lubricating oil aliphatic polyester, wherein the saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in the main chain or a derivative thereof is a succinic acid diester. Saturated aliphatic diols having 4 to 8 carbon atoms in the main chain are 1,4
-Butanediol, 1,5-pentanediol, 1,6
-Hexanediol, 1,7-heptanediol, 1,
The above-mentioned lubricating oil aliphatic polyester, which is at least two kinds of diols selected from 8-octanediol. At least two kinds of diols selected from saturated aliphatic diols having 4 to 8 carbon atoms in the main chain are 1,4-butanediol / 1,5-pentanediol and 1,4-butanediol / 1,6- Hexanediol or 1,4-
The above-mentioned lubricating oil aliphatic polyester which is butanediol / 1,8-octanediol.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The aliphatic polyester of the present invention comprises
It is a low molecular weight polymer obtained by polycondensation of a saturated aliphatic dicarboxylic acid or a derivative thereof and a saturated aliphatic diol. As the saturated aliphatic dicarboxylic acid or its derivative used in the present invention, it is necessary to use a compound having 4 to 10 carbon atoms in the main chain. However, the number of carbon atoms in the main chain refers to the number of carbon atoms in a tandem carbon chain sandwiched between two carboxylic acid groups. If the number of carbon atoms is less than 4, the resulting polyester is not preferred because the viscosity index, which is a measure of the temperature dependence of the viscosity, decreases. If the number of carbon atoms exceeds 10, the resulting polyester deteriorates in low-temperature fluidity. Not preferred.

Examples of the saturated aliphatic dicarboxylic acids or derivatives thereof include saturated aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, and dialkyl esters thereof. Examples include dimethyl ester, methyl ethyl ester, diethyl ester, methyl propyl ester, ethyl propyl ester, dipropyl ester, dibutyl ester and the like. These can be used alone or in combination of two or more. Among the saturated aliphatic carboxylic acids or diesters thereof, succinic acid or diesters thereof are advantageous from the viewpoint of the physical properties of the resulting resin and the price as a raw material. Preferred succinic diesters are dimethyl succinate, diethyl succinate, dibutyl succinate and the like.

As the saturated aliphatic diol, it is necessary to use at least two kinds of diols selected from compounds having 4 to 8 carbon atoms in the main chain. However, the number of carbon atoms in the main chain refers to the number of carbon atoms in a carbon chain arranged in series between two hydroxyl groups. If the number of carbon atoms is less than 4, the viscosity index, which is a measure of the temperature dependence of the viscosity of the resulting polyester, is undesirably reduced. It is not preferable to use a diol having a carbon number of the main chain of more than 8 because the low-temperature fluidity of the obtained polyester is deteriorated. As this saturated aliphatic diol,
Examples include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol. It is necessary to carry out copolycondensation using two or more of these diols. The compounding ratio of two or more diols can be mixed at an arbitrary ratio, but at least one diol needs to be at least 10 mol%. If the amount of one diol is 10 mol% or less, the effect of copolycondensation cannot be obtained. Examples of specific combinations when two types of diols are used include 1,4-butanediol / 1,5-pentanediol, 1,4-butanediol / 1,6-pentanediol, and 1,4-butane Diol / 1,8-pentanediol and the like.

[0010] Further, the polyester low polymer of the present invention has a thickness of 100 to maintain the oil film thickness required for lubrication.
It is necessary that the kinematic viscosity at C is 3 to 50 cSt. If the kinematic viscosity is less than 3, the oil film required for lubrication cannot be maintained, and if it exceeds 50, the fluidity deteriorates, which is not preferable. Those exhibiting this property have a molecular weight (measured by gel permeation chromatography (GPC)) of 300.
~ 1000. Here, if the molecular weight is less than 300, the kinematic viscosity becomes small, and if it exceeds 1,000, it becomes waxy, and all are unsuitable as lubricating base oils.

The method for synthesizing the aliphatic polyester of the present invention may be a known polyester production method. Specifically, there are a direct esterification method and a transesterification method as described below. When a dicarboxylic acid is reacted with two or more diols, a direct esterification method is used, and a dicarboxylic acid diester and two or more diols are used. Is used, the transesterification method is used.

Direct esterification This is a method in which two or more diols and a dicarboxylic acid are dehydrated and condensed in the absence of a catalyst or in the presence of an acid catalyst. The reaction temperature at this time is 100 to 250 ° C., preferably 14 ° C.
Performed at 0-200 ° C. If the reaction temperature is too high, decomposition or solidification occurs, and if it is too low, the reaction does not proceed. The reaction time is 10 minutes to 10 hours, preferably 1 hour to 10 hours. The pressure may be reduced to normal pressure or reduced pressure, or a two-stage reaction may be performed in which a half ester is synthesized at normal pressure and then reduced in pressure.

[0013] The catalyst is usually a cation exchange resin,
Sulfuric acid, hydrochloric acid, p-toluenesulfonic acid, metasulfonic acid, activated clay, various zeolites, silicotungstic acid,
Phosphotungstic acid, an organometallic compound, or the like can be used.

Further, the ratio (molar ratio) of diol and dicarboxylic acid as raw materials is 3 to 15, preferably 4 to 9. If the molar ratio of the dicarboxylic acid to the diol is less than 3, polymerization proceeds too much to obtain a product having a desired kinematic viscosity. On the other hand, if the above molar ratio exceeds 15, polymerization hardly proceeds, and similarly, a product having a desired kinematic viscosity cannot be obtained. The reaction system may be a batch system or a continuous system.

This is a method in which two or more diols and a diester of a dicarboxylic acid are condensed without a catalyst or in the presence of a catalyst. The reaction temperature at this time is 100 to 250 ° C, preferably 140 to 200 ° C. If the reaction temperature is too high, decomposition occurs or polymerization control becomes difficult and solidifies,
If it is too low, the reaction speed is low. The reaction time is 10 minutes to 10 hours, preferably 1 hour to 5 hours. The pressure is normal pressure or reduced pressure.

As the catalyst, Ti, Ge, Zn, Fe,
Mn, Sn, Co, Zr, V, Ir, Ce, Li, Ca
And organic metal compounds such as alkoxide and acetylacetonate. Among them, for example, oxobis (acetylacetonato) titanium, dibutoxydiacetacetoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetrabutoxytitanium and the like are highly active and preferred raw materials. In addition to diesters of dicarboxylic acids, diesters obtained by dehydration-condensation of dicarboxylic acids and arbitrary monohydric alcohols can also be mentioned.

Further, the ratio (molar ratio) of the raw material diol and dicarboxylic acid diester is from 3 to 15, preferably from 4 to 9. If the molar ratio of the dicarboxylic acid diester to the diol is less than 3, polymerization proceeds too much to obtain a product having a desired kinematic viscosity. On the other hand, if the molar ratio exceeds 15, polymerization hardly proceeds,
Similarly, a product having the desired kinematic viscosity is not obtained. The reaction system may be a batch system or a continuous system.

The lubricating oil of the present invention uses an aliphatic polyester alone or as a mixture of two or more as described above. Further, the aliphatic polyester and another lubricating oil can be used in combination. Further, various additives used in conventional lubricating oils, such as load-bearing additives (extreme pressure agents, oil agents,
Abrasion inhibitors, friction modifiers, etc.), chlorine trapping agents, antioxidants, metal deactivators, defoamers, cleaning dispersants, viscosity index improvers, rust inhibitors, corrosion inhibitors, pour point depressants, etc. Can be added as desired.

Examples of the load-bearing additives include monosulfides, polysulfides, sulfoxides, sulfones, thiosulfinates, sulfurized fats and oils, thiocarbonates, thiophenes, thiazoles, methanesulfonic acid esters and the like. Organic sulfur compounds, phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid ester such as phosphoric acid triesters (tricresyl phosphate), phosphorous acid monoesters, phosphorous acid diesters Phosphites such as phosphite triesters, thiophosphates such as thiophosphate triesters, higher fatty acids, hydroxyaryl fatty acids, carboxylic acid-containing polyhydric alcohol esters, metal soaps Fatty acid type, polyhydric alcohol esters, acrylic acid Fatty acid ester-based compounds such as ters, chlorinated hydrocarbons, organic chlorinated compounds such as chlorinated carboxylic acid derivatives, fluorinated aliphatic carboxylic acids, fluorinated ethylene resins, fluorinated alkylpolysiloxanes, fluorinated Organic fluorine compounds such as graphite, alcohol compounds such as higher alcohols, naphthenates (lead naphthenate), fatty acid salts (fatty acid lead), thiophosphates (zinc dialkyldithiophosphate), thiocarbamates, organic There are metal compounds such as molybdenum compounds, organotin compounds, germanium compounds, and borate esters.

Examples of the chlorine scavenger include glycidyl ether group-containing compounds, epoxidized fatty acid monoesters, epoxidized oils and fats, and epoxycycloalkyl group-containing compounds. As antioxidants, phenols (for example,
2,6-di-tert-butyl-P-cresol), aromatic amines (eg, α-naphthylamine) and the like. Examples of the metal deactivator include a benzotriazole derivative. Examples of the antifoaming agent include silicone oil (dimethylpolysiloxane) and polymethacrylates. Examples of the cleaning dispersant include sulfonates, fenotes, salicylates, and succinimides.
Examples of the viscosity index improver include polymethacrylate, polyisobutylene, an ethylene-propylene copolymer, and a styrene-diene hydrogenated copolymer.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. The present invention is not construed as being limited to the following examples. The test method in this example is as follows.

(1) Kinematic viscosity at 100 ° C .: JIS
Canon Automati in accordance with K 2283
c Visometer (CANNON INSTR
UMENT Co).

(2) Viscosity index: Cannon Automatic Visc according to JIS K 2283
meter (CANNON INSTRUMENT
Co).

(3) Pour point: JIS K 2269-1
Automatic pour point cloud point tester (PRC-
106, manufactured by Rigosha Co., Ltd.).

Example 1 A glass four-necked flask was charged with diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
6 g (0.45 mol) and 5.2 g (0.05 mol) of 1,5-pentanediol were added, and the system was heated to 140 ° C. in an oil bath while stirring the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 140 ° C,
0.017 g (0.05%) of Ti (OBu) ₄ as a catalyst
mmol), and the mixture was heated and stirred for 2 hours, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled down to about 100 ° C,
The pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 168.8 g of a polymer.
The kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer were measured, and the results are shown in Table 1.

Example 2 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
5 g (0.25 mol) and 26.0 g (0.25 mol) of 1,5-pentanediol were added, and the system was heated to 140 ° C. in an oil bath while stirring the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 140 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 169.4 g of a polymer. The kinematic viscosity at 100 ° C., the viscosity index and the pour point of the obtained polymer were measured. Table 1 shows the results.

Example 3 In a glass four-necked flask, diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol 4.5
g (0.05 mol) and 1,5-pentanediol 4
6.9 g (0.45 mol) was added, and the system was heated to 140 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 140 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 165.9 g of a polymer. The kinematic viscosity at 100 ° C., the viscosity index and the pour point of the obtained polymer were measured. Table 1 shows the results.

Example 4 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
6 g (0.45 mol) and 5.9 g (0.05 mol) of 1,6-hexanediol were added, and the system was heated to 150 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 150 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 161.8 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Example 5 In a glass four-necked flask, diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol 27.
After adding 0 g (0.30 mol) and 23.6 g (0.20 mol) of 1,6-hexanediol, the system was heated to 150 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 150 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr. Excess diethyl succinate was distilled off under reduced pressure to obtain 163.5 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

The obtained polymer was analyzed by ¹³ C-NMR and IR. In addition, ¹³ C-NMR and IR were measured under the following conditions. ¹³ C-NMR measurement apparatus: JEOL GSX-400 100 MHz (manufactured by JEOL Ltd.) Measurement solvent: CDCl ₃ / TMS 30 ° C. IR measurement apparatus: JASCO IR-810 (manufactured by JASCO Corporation) Analysis result: polybutylene-hexylene succinate It was found that a copolymer was formed.

Example 6 In a glass four-necked flask, diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol 4.5
g (0.05 mol) and 1,6-hexanediol 5
3.2 g (0.45 mol) was added, and the system was heated to 150 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 150 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 163.0 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Example 7 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
6 g (0.45 mol) and 7.3 g (0.05 mol) of 1,8-octanediol were added, and the system was heated to 160 ° C. in an oil bath while stirring the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reached 160 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 157.5 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Example 8 In a glass four-necked flask, diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
5 g (0.25 mol) and 36.6 g (0.25 mol) of 1,8-octanediol were added, and the system was heated to 160 ° C. in an oil bath while stirring the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reached 160 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 159.4 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Example 9 In a glass four-necked flask, diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol 4.5
g (0.05 mol) and 1,8-octanediol 6
5.8 g (0.45 mol) was added, and the system was heated to 160 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reached 160 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 160.3 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

COMPARATIVE EXAMPLE 1 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
1 g (0.5 mol) was added, and 1 g (0.5 mol) was added with an oil bath while stirring the system with a magnetic stirrer under a nitrogen stream.
Heated to 40 ° C. When the temperature in the system reached 140 ° C., 0.017 g (0.05 mm) of Ti (OBu) ₄ was used as a catalyst.
ol), and the mixture was heated and stirred for 2 hours, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 181.9 g of a polymer. Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

The obtained polymer was analyzed by ¹³ C-NMR and IR. In addition, ¹³ C-NMR and IR were measured under the following conditions. ¹³ C-NMR measuring device: JEOL GSX-400 100 MHz (manufactured by JEOL Ltd.) Measurement solvent: CDCl ₃ / TMS 30 ° C. IR measuring device: JASCO IR-810 (manufactured by JASCO Corporation) As a result of analysis, polybutylene succinate is formed I knew I was doing it.

Comparative Example 2 Diethyl succinate 783.
9 g (4.5 mol) and 1,5-pentanediol 5
2.1 g (0.5 mol) was added, and the system was heated to 140 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 140 ° C,
0.017 g (0.05%) of Ti (OBu) ₄ as a catalyst
mmol), and the mixture was heated and stirred for 2 hours, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled down to about 100 ° C,
The pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 168.5 g of a polymer.
Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Comparative Example 3 Diethyl succinate 783.
9 g (4.5 mol) and 1,6-hexanediol 5
9.1 g (0.5 mol) was added, and the system was heated to 140 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 140 ° C,
0.017 g (0.05%) of Ti (OBu) ₄ as a catalyst
mmol), and the mixture was heated and stirred for 2 hours, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled down to about 100 ° C,
The pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 153.9 g of a polymer.
Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Comparative Example 4 Diethyl succinate 783.
9 g (4.5 mol) and 1,8-octanediol 7
3.1 g (0.5 mol) was added, and the system was heated to 140 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 140 ° C,
0.017 g (0.05%) of Ti (OBu) ₄ as a catalyst
mmol), and the mixture was heated and stirred for 2 hours, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled down to about 100 ° C,
The pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 123.9 g of a polymer.
Table 1 shows the measurement results of the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

COMPARATIVE EXAMPLE 5 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
6 g (0.45 mol) and 5.2 g of neopentyl glycol having 5 carbon atoms and 3 carbon atoms in the main chain
(0.05 mol), and the mixture was stirred in an oil bath for 19 minutes with a magnetic stirrer under a nitrogen stream.
Heated to 0 ° C. When the temperature in the system reaches 190 ° C., 0.017 g (0.05 mmo) of Ti (OBu) ₄ is used as a catalyst.
1) Addition, heating and stirring were continued for 2 hours, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 148.5 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

Comparative Example 6 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
5 g (0.25 mol) and neopentyl glycol 2
6.0 g (0.25 mol) was added, and the system was heated to 190 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 190 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr, and excess diethyl succinate was distilled off under reduced pressure to obtain 155.3 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

The obtained polymer was analyzed by ¹³ C-NMR and IR. In addition, ¹³ C-NMR and IR were measured under the following conditions. ¹³ C-NMR measurement apparatus: JEOL GSX-400 100 MHz (manufactured by JEOL Ltd.) Measurement solvent: CDCl ₃ / TMS 30 ° C. IR measurement apparatus: JASCO IR-810 (manufactured by JASCO Corporation) Analysis result: polybutylene neopentyl succinate It was found that a copolymer was formed.

Comparative Example 7 Diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol 4.5
g (0.05mol) and neopentyl glycol 4
6.9 g (0.45 mol) was added, and the system was heated to 190 ° C. in an oil bath while stirring the inside of the system with a magnetic stirrer under a nitrogen stream. When the temperature in the system reaches 190 ° C., 0.017 g of Ti (OBu) ₄ as a catalyst (0.
The mixture was stirred for 2 hours while heating, and the transesterification reaction was completed while distilling off ethanol. Next, while stirring, the temperature in the system was cooled to about 100 ° C., and the pressure was slowly reduced to about 3 Torr. Excessive diethyl succinate was distilled off under reduced pressure to obtain 155.6 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the pour point of the obtained polymer.

[0044]

[Table 1]

As is evident from Table 1, 1,4-butanediol and 1,5-pentanediol were added in 9/1 to 1/9.
The copolycondensation of the diol mixture and diethyl succinate present in the proportion of 1,4-butanediol alone, the pour point is greatly reduced, and the case of 1,5-pentanediol alone It can also be seen that the pour point of the lubricating base oil can be reduced and the lubricating oil base oil has excellent low-temperature fluidity (Example 1).
-3 and Comparative Examples 1-2). Similarly, when a diol mixture in which 1,4-butanediol and 1,6-hexanediol are present in a ratio of 9/1 to 1/9 is co-condensed with diethyl succinate, 1,4-butanediol alone is obtained. And 1,
It can be seen that the pour point is lower than in the case of using 6-hexanediol alone, and the lubricating base oil can be excellent in low-temperature fluidity (Examples 4 to 6 and Comparative Examples 1 and 3). Also, 1,
4-butanediol and 1,8-octanediol are mixed in 9 /
When co-condensation of a diol mixture and diethyl succinate in a ratio of 1/1/9 is carried out, the pour point is lower than that of 1,4-butanediol alone and 1,8-octanediol alone, It can be seen that it can be a lubricating base oil having excellent fluidity (Examples 7 to 9 and Comparative Examples 1 and 4). Further, diethyl succinate and 1,4-butanediol and a diol mixture in which neopentyl glycol having a total number of carbon atoms of 5 and a main chain having 3 carbon atoms are present at a ratio of 9/1 to 1/9 are used. It is found that the copolycondensation lowers the viscosity index than the polycondensate of the present invention, which is not preferable (Comparative Examples 5 to 7).

[0046]

According to the aliphatic polyester obtained by condensing the saturated aliphatic dicarboxylic acid or its derivative with the saturated aliphatic diol according to the present invention, the main chain carbon number of the specific dicarboxylic acid or its ester and the main chain carbon number are specified. The low molecular weight ester copolymer obtained by performing a condensation reaction using at least two types of diols having a specific number is excellent in low-temperature fluidity,
And it has a high viscosity index and has the performance suitable for a lubricating base oil.

Claims (3)

[Claims] 1. A method comprising condensing at least two kinds of diols selected from a saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in a main chain or a derivative thereof and a saturated aliphatic diol having 4 to 8 carbon atoms in a main chain. The kinematic viscosity at 100 ° C obtained by polymerization is 3
An aliphatic polyester for a lubricating base oil having a size of ５０50 cSt. 2. A saturated aliphatic dicarboxylic acid having a main chain having 4 to 10 carbon atoms or a derivative thereof and at least two diols selected from a saturated aliphatic diol having a main chain having 4 to 8 carbon atoms, Using a saturated aliphatic dicarboxylic acid or a derivative thereof in a 3 to 15-fold molar excess with respect to the saturated aliphatic diol, at 140 to 200 ° C in the presence of an organometallic compound catalyst,
A method for producing an aliphatic polyester for a lubricating base oil, wherein the polycondensation reaction is carried out for 1 to 5 hours. 3. Condensation of a saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in the main chain or a derivative thereof and at least two diols selected from saturated aliphatic diols having 4 to 8 carbon atoms in the main chain. The kinematic viscosity at 100 ° C obtained by polymerization is 3
A lubricating oil using an aliphatic polyester of up to 50 cSt.