Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic phosphorus compound – wherein the phosphorus is...
Reexamination Certificate
2001-06-22
2003-01-28
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic phosphorus compound, wherein the phosphorus is...
Reexamination Certificate
active
06511947
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a heat resistant lubricating oil composition having both enhanced heat and oxidation resistance and wear resistance and, which is suitable for the use under high-temperature and high-load lubricating conditions.
BACKGROUND OF THE INVENTION
In recent years, lubricating oils of high quality resistible to severe use conditions are required in accordance with the higher performance and higher efficiency of mechanical devices and power devices. For jet engines, gas turbines, and turbo engines, for example, lubricating oils particularly enhanced heat resistance and oxidation resistance are necessary because of their operations at high temperature.
Accordingly, esters of hindered alcohol with fatty acid such as pentaerythritol or trimethylol propane have been developed as the base oil for jet engine oil so far. In order to satisfy the requirement of USAF Standard MIL-PRF-87100A as jet engine lubricating oil, further, a polyphenyl ether (5P4E) comprising 4-5 aromatic rings connected through oxygen atoms is proposed as a heat resisting lubricating oil having higher heat and oxidation resistances.
However, such a polycyclic polyphenyl ether has deficiencies of high pour point, low viscosity index, and particularly in wear resistance in spite of excellent heat and oxidation resistances.
Therefore, attempts have been made to develop a lubricating oil that also has enhanced wear resistance as well and further is improved in pour point and viscosity index by mixing a polyphenyl thioether with the polyphenyl ether and by adding a phosphorus-type anti-wear agent to address the deficiency in wear resistance. However, the addition of the phosphorus-type anti-wear agent causes the problem of deterioration of heat and oxidation resistances. Applicants' invention addresses the need for compositions having all these characteristics.
SUMMARY OF THE INVENTION
An embodiment of the invention is a heat resisting synthetic lubricating oil composition having enhanced heat and oxidation resistance and wear resistance for use under severe conditions, particularly, high-temperature conditions, which were attainable by the conventional lubricating oils.
The inventors found that a lubricating oil composition consisting of a polyphenyl ether having 4-5 aromatic rings, a polyphenyl thioether having 3-5 aromatic rings, an amine-type antioxidant, a phosphate, and an amine salt of acid phosphate can restrain the inhibiting effect on the heat and oxidation resistance by the phosphorus-type anti-wear agent and exhibit enhanced heat and oxidation resistance and wear resistance which could not be attained by the polyphenyl ether, the polyphenyl thioether, the amine-type antioxidant or the phosphorus-type anti-wear agent alone.
Accordingly, an embodiment of the invention is a lubricating oil composition obtained by mixing, to
(a) a base oil consisting of component (i) or (ii):
(i) a mixture of a polyphenyl ether having 4-5 aromatic rings and/or its hydrocarbon substituted group with a polyphenyl thioether having 3-5 aromatic rings represented by the following general formula [I]
(ii) a polyphenyl thioether having 3-5 aromatic rings represented by the following general formula [I]
wherein R
1
, R
2
and R
3
, which may be the same or different, each represents hydrogen atom or a hydrocarbon group having 1-24 carbon atoms, x, y and z, which may be the same or different, each represents an integer of 1-4, and m represents an integer of 1-3;
(b) an amine-type antioxidant: 0.1-0.8 mass %, on the basis of the total mass of the lubricating oil composition;
(c) a phosphate: 2-3 mass %; and
(d) an amine salt of acid phosphate: 0.07-0.15 mass %.
This invention further involves a second lubricating oil composition obtained by mixing, to
(a) a base oil consisting of a polyphenyl ether having 5 aromatic rings and/or its hydrocarbon substituted group;
(b) a polyphenyl thioether represented by the following general formula [I]: 0.05-5 mass %, on the basis of the total mass of the lubricating oil composition;
wherein R
1
, R
2
and R
3
, which may be the same or different, each represents hydrogen atom or a hydrocarbon group having 1-24 carbon atoms, x, y and z, which may be the same or different, each represents an integer of 1-4, and m represents an integer of 1-3,
(c) an amine-type antioxidant: 0.05-5 mass %;
(d) a phosphate: 2-3 mass %; and
(e) an amine salt of acid phosphate: 0.07-0.3 mass %.
According to this invention, the following 1 and 2 can be given as preferred embodiments.
(1) A heat resisting lubricating oil composition obtained by mixing to a base oil consisting of:
(a) at least one polyphenyl ether selected from the group consisting of bis(m-phenoxyphenyl)ether (mm-4P3E), m-phenoxyphenoxy m-biphenyl (mm-4P2E), m-bis(m-phenoxyphenoxy)benzene (mmm-5P4E) and 5P4E isomeric mixture (a mixture of mmm-5P4E, mmp-5P4E, pmp-5P4E); and
(b) a polyphenyl thioether represented by the general formula [I]:
wherein R
1
, R
2
and R
3
, which may be the same or different, each represents hydrogen atom or a hydrocarbon group having 1-24 carbon atoms, x, y and z, which may be the same or different, each represents an integer of 1-4, and m represents an integer of 1-3,
(a) alkyl naphthylamine: 0.1-0.7 mass %;
(b) tricresyl phosphate: 2-3 mass %; and
(c) aromatic amine salt of acidic phosphate: 0.07-0.15 mass %.
(2) A heat resisting lubricating oil composition obtained by mixing to
(a) a base oil consisting of a mixture of m-bis(m-phenoxyphenoxy) benzene (mmm-5P4E), 1-(m-phenoxyphenoxy)-3-(p-phenoxyphenoxy)benzene (mmp-5P4E) and m-bis(p-phenoxyphenoxy)benzene (pmp-5P4E);
(b) at least one polyphenyl thioether selected from the group consisting of m-bis(phenylmercapto)benzene (m-3P2T), bis(phenylmercapto) benzene isomer mixture (mix-3P2T), bis(m-phenylmercaptophenyl)sulfide (mm-4P3T), bis(phenylmercaptophenyl)sulfide isomeric mixture, m-bis (m-phenylmercaptophenylmercapto)benzene (mmm-5P4T): 0.05-5 mass %;
(c) phenyl-&agr;-naphthylamine and di(alkylphenyl)amine: 0.05-5 mass %;
(d) tricresyl phosphate: 2-3 mass %; and
(e) aromatic amine salt of acidic phosphate: 0.07-0.3 mass %.
Another embodiment of the invention includes the method for enhancing the heat and oxidation wear resistance of an engine by adding to the engine a lubricating oil of the compositions specified above.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention is further described in detail below.
Polyphenyl Ether
The polyphenyl ether used as the component of the heat resisting lubricating oil composition according to this invention comprises aromatic rings bonded through oxygen atom, and it preferably has 4-5 aromatic rings in the molecule.
In the polyphenyl ether used in the lubricating oil composition according to this invention, the ether bond may be located in any position, but preferably in meta-position from the viewpoint of ensuring a low pour point.
Concrete examples of the polyphenyl ether used in the lubricating oil composition according to this invention include bis(m-phenoxyphenyl)ether (mm-4P3E), m-phenoxyphenyl p-phenoxyphenyl ether (mp-4P3E), m-phenoxyphenyl o-phenoxyphenyl ether (mo-4P3E), bis(p-phenoxyphenyl)ether (pp-4P3E), p-phenoxyphenyl o-phenoxyphenyl ether (po-4P3E), bis(o-phenoxyphenyl)ether (oo-4P3E), bis(phenoxyphenyl)ether isomer mixture (mix-4P3E), m-phenoxyphenoxy m-biphenyl (mm-4P2E), m-bis(m-phenoxyphenoxy)benzene (mmm-5P4E), 1-(m-phenoxyphenoxy)-3-(p-phenoxyphenoxy)benzene (mmp-5P4E), p-bis(m-phenoxyphenoxy)benzene (mpm-5P4E), 1-(m-phenoxyphenoxy)-4-(p-phenoxyphenoxy)benzene (pmp-5P4E), p-bis(p-phenoxyphenoxy)benzene (ppp-5P4E), o-bis(m-phenoxyphenoxy)benzene (mom-5P4E), m-bis(o-phenoxyphenoxy)benzene (omo-5P4E), p-bis(o-phenoxyphenoxy)benzene (opo-5P4E), o-bis(o-phenoxyphenoxy)benzene (ooo-5P4E), and bis(phenoxyphenoxy)benzene isomer mixture (mix-5P4E), and these can be used in combination of two ore more so as to provide a liquefied one in ordinary state.
The hydrocarbon substituted group of such a polyphenyl ether can be also used. As
Nakanishi Hiroshi
Umemoto Noboru
Howard Jacqueline V.
Scuorzo Linda M.
Tonen General Sekiyu K.K.
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