JPH1180330A - Aliphatic polyester for lubricating base oil and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject polyester with its dynamic viscosity falling within a specific range and high in biodegradability determined in accordance with the OECD revised MITI procedure, by condensation reaction between a saturated aliphatic dicarboxylic acid and a saturated aliphatic diol, each with the number of carbon atoms in the main chain falling within a specific range. SOLUTION: This aliphatic polyester is obtained by polycondensation between a saturated aliphatic dicarboxylic acid or derivative thereof with the number of carbon atoms in the main chain being 4-10 (pref. a succinic diester) and a saturated aliphatic diol with the number of carbon atoms in the main chain being 4-8 (pref.1,4-butanediol) in the molar ratio of the former to the latter of' 3-15 in the presence of a catalyst [e.g. Ti(OBu)4 ] at 140-200 deg.C for 1-5 h. This polyester is 3-50 cSt in dynamic viscosity at 100 deg.C and >=90% in biodegradability determined in accordance with the OECD 301C revised MITI procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyester polymer for a lubricating base oil having a high viscosity index, excellent biodegradability and an appropriate level of kinematic viscosity.

[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 them are lubricating oils having heat resistance and excellent biodegradability.

[0003]

SUMMARY OF THE INVENTION The present invention provides a heat-resistant lubricating oil having a high viscosity index and an appropriate level of kinematic viscosity and a base oil for a lubricating oil which is excellent in biodegradability and a method for producing the same. The purpose is to:

[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 The aliphatic polyester obtained by performing a condensation reaction using the ester and a specific diol having a main chain carbon number has a high viscosity index, excellent biodegradability, an appropriate kinematic viscosity, and a lubricating oil base. The present inventors have found that they have performance suitable for oil, and have reached the present invention.

That is, according to the present invention, the number of carbon atoms in the main chain is 4 to 4.
A kinematic viscosity at 100 ° C. of 3 to 50 cSt obtained by condensing a saturated aliphatic dicarboxylic acid or a derivative thereof with a saturated aliphatic diol having 4 to 8 carbon atoms in the main chain, and OECD
301C is an aliphatic polyester for a lubricating base oil having a biodegradability of 90% or more as measured according to the modified MITI method. The method for producing the aliphatic polyester is a saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in the main chain. Or a derivative thereof and the main chain having 4 to 4 carbon atoms
Using a saturated aliphatic diol or a derivative thereof in a 3 to 15-fold molar excess with respect to the saturated aliphatic diol in the presence of an organometallic compound catalyst.
The method is characterized in that a polycondensation reaction is performed at a temperature of 200 ° C. for 1 to 5 hours.

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
The above-mentioned lubricating oil aliphatic polyester, which is hexanediol, 1,7-heptanediol or 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 obtained polyester is not preferred because the viscosity index, which is a measure of the temperature dependence of the viscosity, is reduced. It is not preferable because the decomposability decreases.

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.

It is necessary to use a compound having 4 to 8 carbon atoms in the main chain as the saturated aliphatic diol. 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. When a diol having a main chain carbon number of more than 8 is used, the reactivity of the diol decreases, the yield decreases, and the biodegradability decreases, which is not preferable. Examples of the saturated aliphatic diol include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol.

[0010] The polyester low polymer of the present invention needs to have a kinematic viscosity at 100 ° C of 3 to 50 cSt in order to maintain the oil film thickness required for lubrication. 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 these physical properties have a molecular weight (measured by gel permeation chromatography (GPC)) of 300 to 1,000. 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.

Further, the polyester low polymer of the present invention needs to have good biodegradability. Specifically, O
The biodegradability measured by ECD301 modified MITI method needs to be 90% or more. More preferably, 95%
As described above, the content is more preferably 100%.

The method for synthesizing the aliphatic polyester of the present invention may be a known polyester production method. Specifically, there are the following direct esterification method and transesterification method, but use the direct esterification method when reacting a dicarboxylic acid and a diol, and transesterify when reacting a dicarboxylic acid diester with a diol. Method.

Direct Esterification Method This is a method in which a diol 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 140 to 200 ° C.
Done in 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 5 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.

As the catalyst, 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 the starting materials diol and dicarboxylic acid is from 3 to 15, preferably from 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, when the molar ratio exceeds 15,
Since the polymerization hardly proceeds, a product having the desired kinematic viscosity cannot likewise be obtained. The reaction system may be a batch system or a continuous system.

This is a method in which a diester of a diol and a dicarboxylic acid is condensed in the presence of a catalyst. The reaction temperature at this time is
It is carried out at 100 to 250 ° C, preferably 140 to 200 ° C. If the reaction temperature is too high, decomposition occurs or the polymerization is difficult to control and solidification occurs. If the reaction temperature is too low, the reaction rate is low.
The reaction time is 10 minutes to 10 hours, preferably 1 hour to 5 hours.
Time. The pressure is normal pressure or reduced pressure.

As a 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.

The ratio (molar ratio) of the raw material diol and dicarboxylic acid diester is 3 to 15, preferably 4 to 9
It is. When the molar ratio of the dicarboxylic acid diester to the diol is less than 3, the polymerization proceeds too much to obtain a product having a desired kinematic viscosity. On the other hand, when the molar ratio is 1
If it exceeds 5, the 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.

As described above, the lubricating oil of the present invention uses an aliphatic polyester alone or as a mixture of two or more. 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 additive include monosulfides, polysulfides, sulfoxides, sulfones, thiosulfinates, sulfurized fats, 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. Detergents include sulfonates, fenotes, salicylates, succinimides and the like.
Examples of the viscosity index improver include polymethacrylate, polyisobutylene, an ethylene-propylene copolymer, and a styrene-diene hydrogenated copolymer.

[0022]

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) Biodegradability: OECD301 modified MI
It was measured in accordance with the TI method.

Example 1 A glass four-necked flask was charged with diethyl succinate 783.
9 g (4.5 mol) and 1,4-butanediol
1 g (0.5 mol) was added, and the mixture was stirred in an oil bath with a magnetic stirrer under a nitrogen stream.
Heated to 0 ° C. When the temperature in the system reached 140 ° C., 0.017 g (0.05 mmo) of Ti (OBu) ₄ was 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 181.9 g of a 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 apparatus: JEOL GSX-400 100 MHz (manufactured by JEOL Ltd.) Measurement solvent: CDCl ₃ / TMS 30 ° C. IR measuring apparatus: JASCO IR-810 (manufactured by JASCO Corporation)

As a result of analysis, it was found that polybutylene succinate was formed. 100 of the resulting polymer
Table 1 shows the results obtained by measuring the kinematic viscosity, viscosity index, and biodegradability at ° C.

Example 2 In a glass four-neck flask, 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 m) of Ti (OBu) ₄ is used as a catalyst.
mol), 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 168.5 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

Example 3 In a glass four-necked flask, 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 m) of Ti (OBu) ₄ is used as a catalyst.
mol), 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 153.9 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

Example 4 In a glass four-necked flask, 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 m) of Ti (OBu) ₄ is used as a catalyst.
mol), 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 123.9 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

COMPARATIVE EXAMPLE 1 Diethyl succinate 783.
92.1 g (4.5 mol) of neopentyl glycol having 2 carbon atoms and 5 carbon atoms in the main chain
(0.5 mol) and 140 ° C. in an oil bath while stirring the system with a magnetic stirrer under a nitrogen stream.
Until heated. When the temperature of the system reaches 140 ° C., 0.017 g (0.05 mmol) of Ti (OBu) ₄ is used as a catalyst.
The mixture was heated and stirred for 2 hours, and the transesterification 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 143.2 g of a polymer. The obtained polymer was analyzed by ¹³ C-NMR and IR. The analysis was performed in the same manner as in Example 1. As a result of analysis, it was found that polyneopentyl succinate was formed. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

Comparative Example 2 In a glass four-necked flask, diethyl succinate 783.
1,10-decanediol having 9 g (4.5 mol), 10 carbon atoms in the total and 10 carbon atoms in the main chain.
1 g (0.5 mol) was added, and the mixture was stirred in an oil bath with a magnetic stirrer under a nitrogen stream.
Heated to 0 ° C. When the temperature in the system reached 140 ° C., 0.017 g (0.05 mmo) of Ti (OBu) ₄ was 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 87.6 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

Comparative Example 3 In a four-neck glass flask, diethyl succinate 174.
2 g (1.0 mol) 1,4-butanediol 45.1
g (0.5 mol), and the mixture was stirred for 140 minutes in an oil bath with a magnetic stirrer under a nitrogen stream.
Heated to ° C. When the temperature in the system reached 140 ° C., 0.017 g (0.05 mmo) of Ti (OBu) ₄ was 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 178.3 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

Comparative Example 4 Diethyl succinate 139 was placed in a four-neck glass flask.
3.6 g (8.0 mol) of 1,4-butanediol 4
5.1 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 m) of Ti (OBu) ₄ is used as a catalyst.
mol), 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 185.4 g of a polymer. Table 1 shows the results of measuring the kinematic viscosity at 100 ° C., the viscosity index, and the biodegradability of the obtained polymer.

[0036]

[Table 1]

[0037]

The low-polymerized aliphatic polyester of the present invention comprises:
It has a high viscosity index, excellent biodegradability and appropriate kinematic viscosity and can be used as a lubricating base oil.

Claims (3)

[Claims] A kinematic viscosity at 100 ° C. obtained by condensing a saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in a main chain or a derivative thereof with a saturated aliphatic diol having 4 to 8 carbon atoms in a main chain. Is 3 to 50 cSt and OECD301C modified MIT
An aliphatic polyester for a lubricating base oil having a biodegradability of 90% or more as measured according to Method I. 2. A saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in the main chain or a derivative thereof and a saturated aliphatic diol having 4 to 8 carbon atoms in the main chain are saturated with a saturated aliphatic dicarboxylic acid or a derivative thereof. Used in a 3 to 15-fold molar excess with respect to the aliphatic diol and in the presence of an organometallic compound catalyst,
A polycondensation reaction at 0 ° C. for 1 to 5 hours, a kinematic viscosity at 100 ° C. of 3 to 50 cSt, and OECD3
Biodegradability measured according to 01C modified MITI method is 9
A method for producing an aliphatic polyester for a lubricating base oil which is 0% or more. 3. Kinematic viscosity at 100 ° C. obtained by condensing a saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms in the main chain or a derivative thereof with a saturated aliphatic diol having 4 to 8 carbon atoms in the main chain. Is 3 to 50 cSt and OECD301C modified MIT
A lubricating oil using an aliphatic polyester having a biodegradability of 90% or more as measured according to Method I.