JPH09217078A - Heat resistant lubricating oil composition - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a heat-resistant lubricating oil excellent in both oxidation resistance and wear resistance, which is suitable as a lubricating oil for chains of various mechanical devices operated under high temperature and high speed conditions. thing. SOLUTION: The dipentaerythritol ester base oil is added to the lubricating oil composition based on the total weight of (a) diphenylamines of 0.1% to 5% by weight, and (b) phenyl-α-.
Naphthylamines 0.1 wt% to 2 wt%, (c) trisnonylphenylphosphite 0.1 wt% to 5 wt% and (d) phosphoric acid ester 3 wt% to 10 wt% are blended. A heat resistant lubricating oil composition is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant lubricating oil composition, and more particularly, to a composition excellent in both oxidation resistance and abrasion resistance suitable as a lubricating oil for chains of various mechanical devices. The present invention relates to a dipentaerythritol ester-based heat-resistant lubricating oil composition.

[0002]

2. Description of the Related Art Lubricating oils used in various mechanical devices include:
Various additives are added to supplement and further improve the quality. In particular, a lubricating oil used for a lubricated portion of a device operated under high temperature and high speed conditions and under load is required to have wear resistance in addition to oxidation resistance at high temperature. For example, chain lubricating oils to be supplied and applied to chains of various machinery under high temperature by applying or dripping lubrication are required to have specific viscosities and particularly excellent oxidation resistance and wear resistance. I have.

Accordingly, various antioxidants have been studied to satisfy such demands. For example, neopentyl polyol ester-based lubricating oil in which trisnonylphenyl phosphite (TNP) and alkylated diphenylamine are mixed at a specific ratio Antioxidants have been proposed (see Japanese Patent Publication No. 5-3798). According to this publication, as neopentyl polyol esters, neopentyl glycol, trimethylolpropane or pentaerythritol and an ester of a fatty acid having 7 to 20 carbon atoms, specifically, neopentyl glycol isodecanoate,
Trimethylolpropane oleate and pentaerythritol isostearic acid are used, and trisnonylphenyl phosphite (I) and alkylated diphenylamine (II) are used as antioxidants in these base oils.
It is described that the oxidation resistance is improved by mixing and adding (I) :( II) = 1: 1-20.

However, even a lubricating oil obtained by adding the above-mentioned trisnonylphenylphosphite and alkylated diphenylamine to neopentylpolyol ester still has a large evaporation loss at high temperature, and rapidly evaporates and solidifies in a short time. However, it is still inferior in practical use because it is still inferior in oxidation resistance such as the problem of reaching a state, and also lacks in abrasion resistance.

[0005] In view of the above background, development of heat-resistant lubricating oils that can be stably used in chains of various types of machinery under high temperature and load conditions has been desired.

[0006]

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a heat-resistant lubricating oil composition which has both oxidation resistance and wear resistance and can be used under high temperature conditions and load conditions. To do.

[0007]

Means for Solving the Problems Accordingly, the present inventors have:
In view of the development status of the heat-resistant lubricating oil as described above, as a result of intensive studies in order to solve the above-mentioned problems, as a result, specific amine antioxidants and phosphite antioxidants for dipentaerythritol ester base oil It was found that the above-mentioned problems can be achieved by improving the oxidation resistance and the abrasion resistance by blending the above compound and a phosphate ester antiwear additive, and based on this finding, the present invention has been completed.

That is, the present invention relates to a dipentaerythritol ester base oil, based on the total weight of the lubricating oil composition,
(A) The following general formula [I]:

[0009]

Embedded image (In the above general formula [I], R ^{1 to} R ⁴ are each a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms and may be the same or different from each other.). Diphenylamines 0.1% to 5% by weight, (b) the following general formula [II]:

[0010]

Embedded image (In the general formula [II], R ^{5 to} R ⁸ are respectively
A hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, which may be the same or different. 0.1% by weight to 2% by weight, and (c) trisnonylphenylphosphite 0.1.
1 wt% to 5 wt% and (d) the following general formula [IV]:

[0011]

[Chemical 6] (In the general formula [IV], R ^{9 to} R ¹¹ have 1 carbon atoms.
To 18 hydrocarbon groups, which may be the same or different from each other. The present invention provides a heat resistant lubricating oil composition, characterized in that 3% by weight to 10% by weight of a phosphoric acid ester represented by the formula (3) is blended. Furthermore, as a preferred embodiment of the present invention, an ester of dipentaerythritol and 3,5,5-trimethylhexanoic acid is added to (a) dialkyldiphenylamine 0.1% by weight to 5% by weight based on the total weight of the lubricating oil composition. %, (B) Alkylphenyl-α-naphthylamine 0.1% to 2% by weight (c) Trisnonylphenylphosphite 0.1% to 5% and (d) tricresyl phosphate
A heat resistant lubricating oil composition containing 3% by weight to 10% by weight can be provided.

The dipentaerythritol ester base oil used in the present invention is an ester containing dipentaerythritol having a neopentyl group and a fatty acid as constituent components. The fatty acid is not particularly limited, but a linear or branched fatty acid having 7 to 10 carbon atoms is preferable. Specifically, for example, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid,
2-ethylpentanoic acid, 2,2-dimethylpentanoic acid,
2-ethyl-2-methylbutanoic acid, 2-methylheptanoic acid, 2-ethylhexanoic acid, 2-propylpentanoic acid,
2,2-dimethylhexanoic acid, 2-ethyl-2-methylpentanoic acid, 2-methyloctanoic acid, 2,2-dimethylheptanoic acid, 3,5,5-trimethylhexanoic acid, 2,
2-dimethyloctanoic acid etc. can be mentioned. In particular, branched fatty acids having 8 to 9 carbon atoms, such as 3,5,5
-Trimethylhexanoic acid has excellent heat resistance and is suitable as a fatty acid constituting the dipentaerythritol ester of the present invention.

The specific examples of dipentaerythritol esters are as follows (hereinafter, dipentaerythritol is abbreviated as DPE).

That is, DPE hexa (n-heptanoate), DPE hexa (2-ethylpentanoate), DPE hexa (2,2-dimethylpentanoate), DPE hexa (2-ethyl-2-). Methylbutanoate), DPE / hexa (n-octanoate), D
PE / hexa (2-methylheptanoate), DPE /
Hexa (2-ethylhexanoate), DPE / hexa (2-propylpentanoate), DPE / hexa (dimethylhexanoate), DPE / hexa (2-ethyl-2-methylpentanoate), DPE / Hexa (n-
Nonanate), DPE.hexa (2-methyloctanoate), DPE.hexa (2,2-dimethylheptanoate), DPE.hexa (3,5,5-trimethylhexanoate), DPE.hexa (n -Decanoate),
DPE-hexa (2,2-dimethyloctanoate),
DPE-hexa [mixed (n-pentanoate, isopentanoate, n-heptanoate, n-nonanate)]
And the like. The viscosity of the dipentaerythritol ester base oil is in the range of about 120 cSt to about 500 cSt at 40 ° C. in order to stably use it by coating or dripping on the chains of various machines under high temperature conditions. Is preferred, about 200 cSt to about 4
A range of 60 cSt is especially preferred. Kinematic viscosity is about 120c
If it is less than St, the evaporation loss becomes large, and the oil film may be broken and the sliding portion may be worn. On the other hand, about 50
If it exceeds 0 cSt, the load is excessively applied, which causes power loss.

The diphenylamines used in the present invention have the following general formula [I]:

[0016]

Embedded image The compound represented by

In the above general formula [I], R ^{1 to} R ⁴ are
Each is a hydrogen atom or a hydrocarbon having 1 to 18 carbon atoms and may be the same or different from each other. As the hydrocarbon group, a linear or branched alkyl group having 1 to 18 carbon atoms; a linear or branched alkenyl group having 2 to 18 carbon atoms; a cycloalkyl group having 6 to 18 carbon atoms;
To 18 aryl groups and the like, and the aryl group may contain an alkyl group or an alkenyl group having 1 to 12 carbon atoms. Preferred hydrocarbon groups are alkyl groups. For example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group,
Hexadecyl group, heptadecyl group, octadecyl group, and isomers thereof can be mentioned. Particularly preferred alkyl groups are those having 7 to 10 carbon atoms.

The diphenylamines used in the present invention are specifically diphenylamine, p, p'-dibutyldiphenylamine, p, p'-dipentyldiphenylamine, p, p'-dihexyldiphenylamine, p, p '.
-Diheptyldiphenylamine, p, p'-dioctyldiphenylamine, p, p'-dinonyldiphenylamine, monooctyldiphenylamine, monononyldiphenylamine, tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine, having 4 to 4 carbon atoms And 9 mixed alkyldiphenylamines. Among these, alkylated diphenylamine is selected as a preferred diphenylamine, and p, p'-dioctyldiphenylamine is particularly preferred.

The diphenylamines represented by the above general formula [I] are contained in the dipentaerythritol ester base oil in an amount of 0.1% by weight to 5% by weight, preferably 0.5% by weight to the total weight of the composition. 5% by weight is blended.

The phenyl-α-naphthylamines used in the present invention have the following general formula [II]:

[0021]

Embedded image The compound represented by

In the above general formula [II], R ^{5 to} R ⁵
Each of ⁸ is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, which may be the same or different.
Examples of the hydrocarbon group include an alkyl group having 1 to 18 carbon atoms; an alkenyl group having 2 to 18 carbon atoms; a cycloalkyl group having 6 to 18 carbon atoms; an aryl group having 6 to 18 carbon atoms; The group may contain an alkyl group or an alkenyl group having 1 to 12 carbon atoms, and the alkyl group and the alkenyl group may be linear or branched. Preferred hydrocarbon groups are alkyl groups, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl,
Examples include dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, and isomers thereof. Particularly preferred alkyl groups are those having 7 to 10 carbon atoms.

Specific examples of phenyl-α-naphthylamines include phenyl-α-naphthylamine, butylphenyl-α-naphthylamine and pentylphenyl-α-.
Naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine, nonylphenyl-α-
And naphthylamine. Of these, alkylated phenyl-α-naphthylamines such as octylphenyl-α-naphthylamine are particularly preferred. The phenyl-α-naphthylamines represented by the general formula [II] are added to the dipentaerythritol ester base oil in an amount of 0.1% by weight to 2% by weight, preferably 0.1% by weight based on the total weight of the composition.
5 to 2% by weight is blended.

In the present invention, when the diphenylamines represented by the general formula [I] and the phenyl-α-naphthylamines represented by the general formula [II] are used in combination, the oxidation resistance is remarkably improved, Thereby, the object of the present invention can be achieved. Diphenylamines represented by the general formula [I] and phenyl-α represented by the general formula [II]
-Naphthylamines are used by mixing at a weight ratio of 1: 1 to 5: 1, preferably 1: 1 to 4: 1. A preferred embodiment is a 2: 1 weight ratio of p, p'-dioctyldiphenylamine to octylphenyl-α-naphthylamine.
~ 3: 1.

The trisnonylphenyl phosphite used in the present invention has the following formula [III]:

[0026]

Embedded image It is a compound represented by these.

In the above formula [III], the nonyl group is
Any isomer can be used without particular limitation, and examples thereof include a normalnonyl group, a 7-methyl-octyl group, a 6,7-dimethyl-heptyl group, a 5-ethyl-heptyl group, 3,4. 5-trimethyl-hexyl group,
4-isopropyl-hexyl group, 2-ethyl-5-methyl-hexyl group, 2,2,5-trimethyl-hexyl group, 1,2,3,4-tetramethyl-pentyl group, 2,
4-dimethyl-3-ethyl-pentyl group, 2-propyl-4-methyl-pentyl group, 3-isopropyl-4-methyl-pentyl group and the like can be mentioned. Further, the position of the nonyl group substituted with the phenyl group is not particularly limited, and may be any position.

The amount of trisnonylphenyl phosphite represented by the above formula [III] with respect to the base oil is 0.1% by weight to 5% by weight based on the total weight of the composition, and preferably,
It is 0.5% to 3% by weight.

The phosphoric acid ester used in the present invention has the following general formula [IV]:

[0030]

Embedded image The compound represented by is preferred.

In the above general formula [IV], R ^{9 to} R ¹¹
Are hydrocarbon groups having 1 to 18 carbon atoms and may be the same or different from each other. As the hydrocarbon group hydrogen group, a linear or branched alkyl group having 1 to 18 carbon atoms; a cycloalkyl group having 6 to 18 carbon atoms; 6 to 1 carbon atoms
8 aryl groups can be mentioned. Aryl group has 1 to 1 carbon atoms
It may have 12 alkyl groups. According to the present invention, a triaryl phosphate in which R ⁹ , R ¹⁰ and R ^{11 of} the above general formula [IV] are aryl groups is preferable, and specific examples of the triaryl phosphate include benzyldiphenyl phosphate, triphenyl phosphate, Examples thereof include tricresyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, and ethyl diphenyl phosphate partially having an alkyl group can be used, but tricresyl phosphate is particularly preferable.

The amount of the phosphoric acid ester blended is 3% by weight to 10% by weight, preferably 3% by weight to 8% by weight, based on the total weight of the composition.

In preparing the heat resistant lubricating oil composition of the present invention, in addition to the above-mentioned essential additives, if necessary, various additives usually used, for example, a corrosion inhibitor, a pour point depressant, A metal deactivator, a viscosity index improver, etc. can be used.

The heat-resistant lubricating oil composition of the present invention comprises a dipentaerythritol ester base oil (a) diphenylamines, (b) phenyl-α-naphthylamines, and (c).
Trisnonylphenyl phosphite and (d) phosphate ester are contained as essential components,
As a high-temperature lubricating oil, it exhibits excellent performance in both oxidation resistance and wear resistance. Therefore, the lubricating oil can be used in a high temperature section of various mechanical devices, and is extremely suitable as a lubricating oil used for application or dripping oil supply to a chain portion of various mechanical devices such as a biaxial stretching machine and a bread making device.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION

[0036]

EXAMPLES Examples of the present invention will be described below, but these are for describing the embodiments of the present invention in detail, but not for limiting the present invention.

Regarding performance evaluation, oxidation resistance and abrasion resistance were evaluated by the following test methods. (1) Oxidation resistance (oven test) 20 g of sample oil and 5 g of iron powder are put into a beaker having a capacity of 50 ml, stirred, and then allowed to stand in an oven at 230 ° C. After the start of the test, a fixed time (48 hours, 96 hours, 144 hours
........) The beaker was taken out of the oven every time the weight of the beaker was measured, and the evaporation loss and the solidification time were measured. (2) Abrasion resistance (SRV friction and abrasion test) The abrasion resistance of the sample oil was measured using a reciprocating sliding friction and abrasion tester "SRV friction and abrasion tester" manufactured by Optimol, frequency: 50 Hz, amplitude: 1 mm , Load: 50N, temperature: 2
30 ° C, test time: 10 minutes, material of test piece (ball / plate):
It was measured under the test conditions of SUJ2 / SUJ2 (high carbon chromium steel).

Example 1 An ester of dipentaerythritol and 3,5,5-trimethylhexanoic acid [DPE-hexa (3,5,5-trimethylhexanoate)] was added to p, p'-dioctyldiphenylamine and octylphenyl. -Α-naphthylamine, trisnonylphenyl phosphite and tricresyl phosphate were blended to give a kinematic viscosity of the following composition 33
A prototype oil A of 0 cSt (@ 40 ° C.) was obtained. Prototype oil A 1 (composition) Base oil DPE / hexa (3,5,5-trimethylhexanoate) 87% by weight additive p, p′-dioctyldiphenylamine (DPA) 3% by weight octylphenyl-α-naphthylamine (OPAN) ) 1% by weight Trisnonylphenyl phosphite (TNP) 1% by weight tricresyl phosphate (TCP) 8% by weight (Performance evaluation) The prototype oil A prepared as described above was evaluated for its oxidation resistance and abrasion resistance. I went to Oxidation resistance oven test Table 1 and Figure 1 show the oven test data. When heated for 336 hours, the evaporation loss was 63
%, And the remaining sample solidified. Hereinafter, the heating time until the evaporation residue is solidified is referred to as "solidification time". Abrasion resistance SRV friction and wear test SRV wear scar diameter: 0.26 mm Trisnonylphenyl phosphite and tricresyl phosphate were blended to obtain a trial oil B having the following composition. Prototype oil B (Composition) Base oil DPE / hexa (3,5,5-trimethylhexanoate) 89.6% by weight additive p, p'-dioctyldiphenylamine (DPA) 2.4% by weight octylphenyl-α- Naphthylamine (OPAN) 1% by weight Trisnonylphenyl phosphite (TNP) 3% by weight tricresyl phosphate (TCP) 4% by weight (Performance evaluation) Prototype oil B was subjected to the oven test and the SRV friction and wear test as in Example 1. When provided, the evaluation results shown in Table 1 were obtained. The evaporation loss curve is shown in FIG.

Comparative Example 1 Trisnonylphenyl phosphite (3% by weight) was added to the ester of dipentaerythritol and 3,5,5-trimethylhexanoic acid, and the kinematic viscosity shown in Table 1 was 400 cSt.
A trial oil a of (@ 40 ° C.) was prepared. When the trial oil a was subjected to the above-mentioned performance evaluation of oxidation resistance and wear resistance, the evaluation results shown in Table 1 and FIG. 1 were obtained.

COMPARATIVE EXAMPLE 2 2.4% by weight of p, p'-dioctyldiphenylamine was added to an ester of dipentaerythritol and 3,5,5-trimethylhexanoic acid to give a kinematic viscosity 410c shown in Table 1.
A trial oil b of St (@ 40 ° C.) was prepared. The trial oil b was subjected to the above performance evaluation, and the evaluation results shown in Table 1 and FIG. 1 were obtained.

Comparative Example 3 An ester of dipentaerythritol and 3,5,5-trimethylhexanoic acid was mixed with 2.4% by weight of p, p'-dioctyldiphenylamine and 3% by weight of trisnonylphenylphosphite, and Table 1 The trial oil c shown in was prepared.

The trial oil c was subjected to the above-mentioned performance evaluation of oxidation resistance and wear resistance, and the evaluation results shown in Table 1 and FIG. 1 were obtained.

Comparative Example 4 Prototype oil d shown in Table 1 was obtained in the same manner as in Example 2 except that octylphenyl-α-naphthylamine was removed. When the trial oil d was subjected to the above-mentioned performance evaluation of oxidation resistance and wear resistance, the results shown in Table 1 and FIG. 1 were obtained. Reference Example 1-3 A commercial product containing a mixed oil of polybutene and trimethylolpropane ester as a base oil (Reference Example 1), a commercial product containing a mixed oil of polybutene and pentaerythritol ester as a base oil (Reference Example 2), and When the above-mentioned performance evaluation was performed on a commercial product (Reference Example 3) containing dipentaerythritol as a base oil, the results shown in Table 2 were obtained.

From the above Example 1, Comparative Example and Reference Example, the dipentaerythritol ester base oil according to the present invention and two different amine antioxidants, phosphite antioxidants and phosphates It is understood that the combination with the system antiwear additive results in a heat resistant lubricating oil with excellent oxidation and wear resistance. That is, in Comparative Example 1, only phosphite-based trisnonylphenylphosphite was blended as an antioxidant, and in Comparative Example 2, only p, p′-dioctyldiphenylamine was blended as an antioxidant, and In Example 3, both trisnonylphenylphosphite and p, p'-dioctyldiphenylamine were blended, but the oxidation resistance was still poor. Octylphenyl-α-
By further blending naphthylamine, a marked improvement in oxidation resistance was observed for the first time as shown in Example 1, and by blending tricresyl phosphate, it was excellent in oxidation resistance and abrasion resistance, and had a good overall quality. It has been found that the chain lubricating oil of the present invention can be provided.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

As described above, a heat-resistant lubricating oil composition comprising the dipentaerythritol ester base oil of the present invention, the above-mentioned three-component antioxidant and one-component antiwear agent as essential components, It has high practical value such as excellent evaporation resistance with small evaporation loss and extremely long solidification time, and also excellent abrasion resistance. Accordingly, the lubricating oil according to the present invention has a high effect particularly as a high-temperature lubricating oil used for a chain portion of a mechanical device operated at high temperatures.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between heating time and evaporation loss in an oven test.

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Claims (1)

[Claims] 1. A dipentaerythritol ester base oil, based on the total weight of the lubricating oil composition, (a) having the following general formula [I]: (In the above general formula [I], R ^{1 to} R ⁴ are each a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms and may be the same or different from each other.). Diphenylamines 0.1% to 5% by weight, (b) the following general formula [II]: (In the general formula [II], R ^{5 to} R ⁸ are respectively
A hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, which may be the same or different. 0.1% by weight to 2% by weight, and (c) trisnonylphenylphosphite 0.1.
1 wt% to 5 wt% and (d) the following general formula [IV] (In the general formula [IV], R ^{9 to} R ¹¹ have 1 carbon atoms.
To 18 hydrocarbon groups, which may be the same or different from each other. ] The heat resistant lubricating oil composition characterized by mix | blending 3 weight% -10 weight% of phosphoric acid ester represented by these.