JPH03199295A - Base oil for engine oil - Google Patents

Abstract

PURPOSE:To provide the subject base oil containing neopentyl polyol and a synthetic ester produced from neo acid, etc., at a specific ratio, having excellent stability to heat and oxidation and exhibiting high hydrolysis stability. CONSTITUTION:The objective oil contains (A) a neopentyl polyol and (B) >=10wt.% of a synthetic ester produced by using (i) >=10mol% of a neo acid of formula (R is 1-8C alkyl; R<1> and R<2> are 1-2C alkyl) and (ii) <=90mol% of a monocarboxylic acid other than neo acid as constituent fatty acid. The component A is e.g. neopentyl glycol, trimethylolethane, trimethylolpropane and (di) pentaerythritol.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses neoacid as a raw fatty acid, and optionally uses a monocarboxylic acid other than neoacid as a part of the raw fatty acid to produce neopentyl polyol. This invention relates to an engine oil base oil containing a synthetic ester used as a raw material alcohol.

[Conventional technology]

Lubricating oils currently used as engine oil base oils are broadly classified into mineral oils and synthetic oils, and the latter are further divided into synthetic hydrocarbons, diesters, and hindered esters. These engine oil base oils include low volatility,
Performance requirements include a high viscosity index, good low-temperature fluidity, low thermal and oxidative stability, and high hydrolytic stability.

Mineral oil is currently widely used as an engine oil base oil because it is cheap, but it has a high volatile content and a low viscosity index.
It has drawbacks such as poor low-temperature fluidity and poor thermal and oxidative stability.

In order to improve the drawbacks of this mineral oil, the above-mentioned synthetic alcoholic beverages have been developed and used. Synthetic hydrocarbons, one of them, have lower volatility than mineral oils of the same viscosity grade.

It also has the advantage of good thermal and oxidative stability. However, the viscosity index is lower than that of ester-based lubricating oils.

Compared to synthetic hydrocarbons, diesters have lower volatility, higher viscosity index, and better cold flow properties. but,
Thermal and oxidative stability is inferior to synthetic hydrocarbons. It also has the disadvantage of being easily hydrolyzed.

Compared to these mineral oils, synthetic hydrocarbons, and diesters, hindered esters are engine oil base oils with the best total balance. Hindered esters, like diesters, have low volatility. In addition, although the viscosity index and low-temperature fluidity are slightly inferior to diesters, they are sufficiently better than mineral oils. It has the best thermal and oxidative stability compared to other engine oil base oils.

However, despite these advantages, hindered esters, like diesters, have the disadvantage of being easily hydrolyzed [Lubrication Handbook Revised Edition, Japanese Society of Lubricant and Oil Research, Published by Yokendo]. This drawback becomes a problem when water gets mixed into the engine oil.

Despite the disadvantage of being susceptible to hydrolysis, hindered esters are widely used as high-performance engine oil base oils due to their excellent thermal and oxidative stability. However, due to the harsher operating conditions associated with recent improvements in engine performance, not only other oils, but even hindered esters still have inadequate thermal and oxidative stability, making them unusable. [Tribocyst, Vol. 34, No. 2, pp. 144-147 (1989
Year)〕.

[Problem to be solved by the invention]

As described above, conventionally known hindered ester engine oil base oils have problems with hydrolytic stability, and those that have sufficient thermal and oxidative stability to be used as engine oil base oils for high-performance engines. I couldn't necessarily say that.

In view of the above circumstances, an object of the present invention is to provide an engine oil base oil having excellent thermal and oxidative stability and good hydrolytic stability.

(Means for Solving the Problems) As a result of intensive studies to achieve the above object, the present inventors have found that neopentyl polyol, neoacid, and in some cases monocarboxylic acids other than neoacid are used as raw materials. The present inventors have discovered that an engine oil base oil made of a synthetic ester has good thermal and oxidative stability as well as good hydrolytic stability, and have completed the present invention.

That is, the present invention provides neopentyl polyol and the following formula whose proportion in the total fatty acid is 10 mol % or more; is an alkyl group having 1 to 2 carbon atoms> and a monocarboxylic acid other than the neoacid that accounts for 90 mol% or less of the total fatty acids. It pertains to engine oil base oil containing % by weight.

C Structure and Effect of the Invention] Examples of the neopentyl polyol used in the present invention include neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, and the like. These alcohols may be used alone or in combination of two or more.

The neoacid represented by the following formula used in the present invention; -dimethylpropanoic acid, 2,2-dimethylbutanoic acid, 2,2-dimethylpenconic acid, 2,2-dimethylhexanoic acid, 2,2-dimethylhebutanoic acid, 2,
Examples include 2-dimethyloctanoic acid, 2-methyl, 2-ethylbutanoic acid, 2-methyl, and 2-ethylpentanoic acid. In terms of thermal and oxidative stability, those in which R has 4 or less carbon atoms are particularly preferred. These neoacids may be used alone or in combination of two or more.

Monocarboxylic acids other than neoacids used in the present invention include:
butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid,
pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, 2-ethylhexanoic acid, isononanoic acid, 3゜5.5-trimethylhexanoic acid,
These include isostearic acid and oleic acid. In particular, heat
In terms of oxidative stability, carboxylic acids having 10 or less carbon atoms are preferred.

These monocarboxylic acids may be used alone or in combination of two or more.

The amount of the above neoacid and other monocarboxylic acids to be used is such that the proportion of neoacid in the total amount of both, that is, the proportion of neoacid in the total fatty acid, is 10 mol% or more, and the proportion of other monocarboxylic acids is 10 mol% or more. It needs to be 90 mol% or less,
Particularly preferably, the amount of neoacid is 30 mol% or more, and the amount of other monocarboxylic acids is 70 mol% or less. When the neoacid content is less than 10 mol %, not only good thermal and oxidative stability cannot be obtained, but also good hydrolytic stability cannot be obtained.

The synthetic ester in the present invention can be synthesized, for example, by reacting the neopentyl polyol described above with the acid chloride of the neoacid described above.

In addition, when using a monocarboxylic acid other than neo-acid as part of the raw fatty acid, an ester with an unreacted hydroxyl group obtained by reacting neopentyl polyol and neo-acid chloride and a monocarboxylic acid other than neo-acid are used. It is synthesized by direct esterification with an acid, or conversely, it is synthesized by direct esterification of an ester with an unreacted hydroxyl group obtained by reacting a monocarboxylic acid other than neoacid with neoacid. be able to.

The synthetic ester in the present invention can also be synthesized by conventional direct esterification of neopentyl polyol and the above-mentioned neoacid or with another monocarboxylic acid. Furthermore, in this case, when neoacid and other monocarboxylic acids are used together, both fatty acids may be charged at the same time and reacted with neopentyl polyol, or one fatty acid, boric acid, may be reacted with neopentyl polyol. After the reaction, the other fatty acid may be added and reacted.

In such a synthetic reaction, the reaction molar ratio between neopentyl polyol and raw fatty acid or its acid chloride is not particularly limited, but if the hydroxyl value of the resulting synthetic ester is too high, the viscosity index will deteriorate. If the acid value is too high, thermal and oxidative stability may be deteriorated, so usually the carinyl group of the fatty acid or its acid chloride is 0.9 to 1 equivalent of the hydroxyl group of the neopentyl polyol. It is preferable to react at a rate such that the amount is 1.1 equivalent.

After the above esterification reaction, the resulting synthetic ester is
It can be purified through general purification steps such as alkaline water washing, water washing, distillation, and adsorption treatment. From the above-mentioned viewpoint, the acid value and hydroxyl value after purification are preferably 1 ■KOH/g or less in acid value and 40 ■KOJI/g or less in hydroxyl value. Further, in the case of an ester synthesized using fatty acid chloride, residual chlorine causes corrosion, so it is desirable that the chlorine concentration is 50 ppm or less.

In the present invention, the synthetic ester thus obtained may be used alone as an engine oil base oil, or
If necessary, this may be used in combination with other oils such as mineral oils, poly-α-olefins, diesters, polyphenyl ethers, fluorine compounds, phosphoric esters, silicones, particularly preferably poly-α-olefins, diesters or mixtures thereof. Good too. In the latter combination system, it is necessary to use the above synthetic ester in an amount of 10% by weight or more, particularly preferably 20% by weight or more. The amount of the above ester used is 1
If it is less than 0% by weight, good thermal and oxidative stability cannot be obtained.

The engine oil base oil of the present invention contains various commonly used load-bearing additives, antioxidants, detergent dispersants, antifoaming agents, rust preventives, demulsifiers, pour point depressants, viscosity index improvers, etc. Additives can be added as necessary.

〔Effect of the invention〕

The engine oil base oil of the present invention not only has good thermal and oxidative stability, but also has good hydrolytic stability.
It can be used as an engine oil base oil for cycle engines, and is particularly suitable as an engine oil base oil for high-performance engines.

In addition, the engine oil base oil of the present invention has excellent thermal and oxidative stability and good hydrolytic stability, so it can be used not only as an engine oil base oil but also as a plasticizer, lubricant, mold release agent for synthetic resins, etc. Additives such as crystallization promoters, electrical insulation oil, refrigeration oil,
It can also be used for oils that require thermal/oxidative stability and hydrolytic stability, such as hydraulic oil, compressor oil, and heat medium.

Furthermore, the engine oil base oil of the present invention can sufficiently exhibit its effects even when various conventionally known additives are added thereto.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited only to these Examples.

Example 1 An 11 four-loaf flask was equipped with a stirrer, thermometer, addition funnel, and condenser. 134.2 g (1 mol) of trimethylolpropane was charged into this flask, and the temperature was 85°C.
It was dissolved by raising the temperature to . 445.5 g (3 moles) of 2,2-dimethylpenconic acid chloride was added dropwise to this using a dropping funnel. After reacting at 85° C. for 1 hour, unreacted chloride was decomposed with an aqueous KOH solution, and the resulting acid was neutralized. After washing with water, 95℃, 2011Hg,
It was dehydrated for 1 hour and further filtered to obtain a synthetic ester, which was used as sample N11l engine oil base oil.

Example 2 Equivalence ratio of alcohol and fatty acid chloride to 1:1
．． A synthetic ester was obtained in the same manner as in Example 1, except that the sample was changed to 1, and this was used as the engine oil base oil of Sample Kou 2.

Example 3 Equivalence ratio of alcohol and fatty acid chloride to 1:0
．． A synthetic ester was obtained in the same manner as in Example 1, except that 9 was used, and this was used as the engine oil base oil of Sample No. 3.

Example 4 A tank fitted with a stirrer, thermometer, addition funnel and cooling tube
In a 4-liter flask, add 13 liters of trimethylolpropane.
4.2g (1 mol) was charged and the temperature was raised to 85°C to dissolve it. To this, 120 2,2-dimethylpropanoyl chloride
．． 6 g (1 mol) was added dropwise using a dropping funnel and reacted at 85° C. for 1 hour.

After the reaction is complete, replace the dropping funnel with the nitrogen blowing tube, attach the suspension tube to the cooling tube and flask, and add caprylic acid 2.
88.4 g (2 mol) was charged. The reaction was carried out at 220° C. for 10 hours while blowing nitrogen. As an esterification catalyst, P-)luenesulfonic acid was added at a rate of 0.3% based on the total weight of the reactant in the flask and the newly charged carbonic acid.
% by weight was added. After the reaction is complete, neutralize the unreacted acid with KOH and add water? After 'A, it was dehydrated under conditions of 95°C, 2QmmHg, and 1 hour, and further filtered to obtain a synthetic ester, which was used as sample 4 engine oil base oil.

Example 5 A fourth flask of 11 was fitted with a suspension tube fitted with a stirrer, a thermometer, a nitrogen sparge and a condenser. In this flask, 136 g (1 mol) of pentaerythritol,
232.3 g (2 moles) of 2,2-dimethylbutanoic acid, 88 g (1 mole) of butyric acid, and 116.2 g (1 mole) of Capron M were charged. 10 at 220℃ while blowing nitrogen
Allowed time to react. As an esterification catalyst, p-)luenesulfonic acid was used in an amount of 0.3% by weight based on the total amount charged. After the reaction is complete, neutralize the unreacted acid with KOH, wash with water, and heat to 95°C.
, 20nl1g, dehydrated for 1 hour, and further filtered to obtain a synthetic ester, which was used as sample No. 5 engine oil base oil.

Example 6.7 Two types of synthetic esters were obtained in the same manner as in Example 5, except that the blending composition of alcohol and fatty acid was changed as shown in Table 1, and these were used as sample 11h6. 7 engine oil base oil.

Example 8 Using the synthetic ester obtained in Example "1", this ester 2
0 parts by weight, 80 parts by weight of poly-α-olefin (LIPOLUBE 25 from Lion ■) with an average molecular weight of 400 was stirred and mixed in a beaker to form a sample! 118 engine oil base oil.

Examples 9 to 11 Three types of synthetic esters were obtained in the same manner as in Example 5, except that the blending composition of alconyl and fatty acid was changed as shown in Table 1. Poly-α-olefin (L IPOLU
BE25) or this and diisodecyl adipate [Shin Nippon Rika ■] are stirred and mixed in a beaker to prepare the sample! l
It was set as an engine oil base oil of h9 to 1lhll.

Comparative Examples 1 to 3 As shown in Table 1, three types of synthetic esters in which the proportion of neoacids in the total fatty acids was 0 mol% or 5 mol% were obtained in the same manner as in Example 5, and these Sample ester f
The engine oil base oil was lh12 to m14.

Comparative Example 4 The engine of sample 11h15 was produced in the same manner as in Example 8, except that the blending ratio of the synthetic ester obtained in Example 1 and the poly-α-olefin was changed from 5 parts by weight of the former to 95 parts by weight of the latter. Oil base oil was obtained.

The physical property values (kinematic viscosity, viscosity index,
The results of the investigation (acid value, hydroxyl value, pour point) are shown in the following
Shown in the table.

In Table 1, in the column of reaction charge ratio of synthetic ester, "N5" is 2,2-dimethylpropanoic acid or its acid chloride [Shell Kagaku ■], and "N6" is 2,2-dimethylbutanoic acid ( Shell Chemical ■), rN7J is 2,2-
Dimethylpenconic acid or its acid chloride [Shell Chemical ■], "N8" is 2-methyl, 2-ethylbutanoic acid [
"N9" is 2,2-dimethylhebutanoic acid (Exxon Chemical Co., Ltd.), and rNloJ is 2,2-dimethyloctanoic acid (Shell Chemical Co., Ltd.), both of which are neo-acid components.

- "nC4" is butyric acid [Wako Pure Chemical Industries 01], rn
C6J is caproic acid (UNION CARBTDE)
Co, ), rnct J is n-hebutanoic acid [Toyo Gosei ■], rncsJ is caprylic acid [NOF-N
AA-82), rnc+oJ is capric acid [NOF ■], rbcaJ is octylic acid [Kyowa Hakko ■],
All of them are monocarboxylic acid components other than neoacid.

Furthermore, rTMPJ is trimethylolpropane [Koei Chemical Industry ■], "PE" is pentaerythritol [Koei Chemical Industry side], and rDPEJ is dipentaerythritol [Koei Chemical Industry side], all of which are neopentyl polyol components.

In addition, in the same table, in the column for the blending ratio of other oils, "poly-
"α" is a poly-α-olefin with an average molecular weight of M400 (LIPOLUBE25 from Lion ■), and "diester" is diisodecylazibeto (Shin Nippon Rika ■).

Next, a thermal/oxidative stability test was conducted on each of the engine oil base oils of samples 1 to 15 above based on the lubricant oxidation stability test for internal combustion engines, 3.1 of JIS K2514-1982. That is, 250 m of sample oil was maintained at 165.5°C in the presence of copper and a copper catalyst and oxidized for 96 hours, and then the increase in total acid value and change in viscosity were examined. The test results were as shown in Table 2 below.

Table 2 Furthermore, a hydrolysis stability test was conducted on each of the engine oil base oils of Samples 1 to 15 above based on the Rolls-Royce 1006 method. That is, 250 ml of sample oil was shaken at 90°C, and the acid value was determined 28 days later. The test results were as shown in Table 3 below.

Table 3 As is clear from the results in Tables 2 and 3 above,
The engine oil base oil of the present invention is thermally and oxidatively stable.
It can be seen that there is a decrease in both l and hydrolytic stability.

Claims (1)

[Claims] (1) Neopentyl polyol and the following formula that accounts for 10 mol% or more in the total fatty acid; ,R_
2 is an alkyl group having 1 to 2 carbon atoms) and a monocarboxylic acid other than the neoacid that accounts for 90 mol% or less of the total fatty acids. Engine oil base oil containing 10% by weight.