LUBRICANT COMPOSITION

Abstract

An object is to provide a lubricant oil composition excellent in biodegradability, lubricating property (extreme pressure property), stability against oxidation and demulsibility, having low toxicity and bioaccumulation property in an aquatic life, and excellent in stability against shearing even in the presence of water.

A lubricant oil composition comprises 100 mass parts of the following ester compound (A), 0.1 to 1.5 mass parts of the following amine salt (B) of an acidic phosphoric acid ester, 0.3 to 2.0 mass parts of an amine-based oxidation preventing agent (C), and 0.3 to 2.0 mass parts of a phenol-based oxidation preventing agent (D), (A) the ester compound comprising a molar percentage of 20 to 30 mol % of a constituent component (a) derived from pentaerythritol, a molar percentage of 55 to 79 mol % of a constituent component (b) derived from a straight-chain fatty acid having a carbon number of 14 to 22, and a molar percentage of 1 to 15 mol % of a constituent component (c) derived from adipic acid, wherein a ratio [(c) mol %/(b) mol %] of the molar percentage of the constituent component (b) with respect to the molar percentage of the constituent component (c) is 0.02 to 0.25 and wherein the ester compound has a hydroxyl value of 10 to 100 mgKOH/g, (B) the amine salt of an acidic phosphoric acid ester represented by the following formula (1),

##STR00001## (in the formula (1), n represents an integer of 1 or 2, R represents a straight-chain alkyl group having a carbon number of 4 to 6, and R represents hydrogen or an alkyl group having a carbon number of 11 to 14.).

Claims

1. A lubricant oil composition comprising 100 mass parts of the following ester compound (A), 0.1 to 1.5 mass parts of the following amine salt (B) of an acidic phosphoric acid ester, 0.3 to 2.0 mass parts of an amine-based oxidation preventing agent (C), and 0.3 to 2.0 mass parts of a phenol-based oxidation preventing agent (D), (A) said ester compound comprising a molar percentage of 20 to 30 mol % of a constituent component (a) derived from pentaerythritol, a molar percentage of 55 to 79 mol % of a constituent component (b) derived from a straight-chain fatty acid having a carbon number of 14 to 22, and a molar percentage of 1 to 15 mol % of a constituent component (c) derived from adipic acid, wherein a ratio [(c) mol %/(b) mol %] of said molar percentage of said constituent component (b) derived from said straight-chain fatty acid with respect to said molar percentage of said constituent component (c) derived from adipic acid is 0.02 to 0.25 and wherein said ester compound has a hydroxyl value of 10 to 100 mgKOH/g, (B) said amine salt of an acidic phosphoric acid ester represented by the following formula (1), ##STR00004## (in the formula (1), n represents an integer of 1 or 2, R represents a straight-chain alkyl group having a carbon number of 4 to 6, and R represents hydrogen or an alkyl group having a carbon number of 11 to 14.).

Description

EXAMPLES

[0077] The present invention will be described in detail below, referring to the inventive and comparative examples.

(Synthesis of Ester Compound)

Synthetic Example 1

[0078] Into a 3-liter four-necked flask equipped with a thermometer, nitrogen supply tube, agitator and cooling funnel, 285 g (2.09 mol) of pentaerythritol, 88 g (0.60 mol) of adipic acid, and 1728 g (6.21 mol) of straight-chain fatty acids (myristic acid: 2.0 mass %, myristoleic acid: 1.4 mass %, pentadecenoic acid: 0.2 mass %, palmitic acid: 4.2 mass %, palmitoleic acid: 7.0 mass %, heptadecenoic acid: 1.6 mass %, stearic acid: 1.2 mass %, oleic acid: 73.8 mass %, linoleic acid: 6.7 mass %, linolenic acid: 1.8 mass %, arachidic acid: 0.1 mass %) were charged, followed by the reaction at 240 C. at ambient pressure under nitrogen gas flow, while water generated through the reaction was removed. After the reaction product was cooled, 0.5 mass parts of active white clay was added to the reaction product to perform the adsorption, followed by filtration to remove the adsorption agent to obtain the ester compound A1.

Synthetic Example 2

[0079] The charged amounts of the raw materials were changed based on the same procedure as that of the synthetic example 1, to obtain the ester compounds A2 and A1.

[0080] The molar percentages of the components derived from the respective raw materials of the ester compounds A1, A2 and A1 obtained as above were measured by 1H NMR and described in table 1. The measurement results of the acid values, hydroxyl values, kinetic viscosities at 40 C., kinetic viscosities at 100 C., viscosity indices and flash points were also described in table 1.

Inventive Examples 1 to 5 and Comparative Examples 1 to 5

(Preparation of Lubricating Oil Composition)

[0081] The additives were blended into the ester compounds A1, A2 and A1 obtained as described above according to the following procedure, to prepare the lubricating oil compositions of the inventive examples 1 to 5 and comparative examples 1 to 5.

[0082] In a 3-liter four-necked flask equipped with a thermometer, nitrogen supply tube, agitator and cooling funnel, the following additives were added in the blending ratios described in tables 2 and 3 into the ester compounds A1, A2 and A1 synthesized as above, followed by agitation and mixing at 120 C. for 2 hours to obtain lubricating oil compositions.

[0083] Further, the following additives were applied.

(Extreme Pressure Agent)

[0084] (B) mono/di hexyl phosphate-C11 to 14-branched alkyl amine salt (BASF corporation, IRGALUBE 349) [0085] Branched butyl phosphate-C11 to 14 branched alkyl amine salt (LANXESS corporation, RC3740) [0086] Dibenzyl disulfide

(Amine-Based Oxidation Preventing Agent)

[0087] N-[4-(1,1,3,3-tetramethylbutyl)phenyl]-1-naphthylamine (BASF Corporation, IRGANOX L06)

(Phenol-Based Oxidation Preventing Agent)

[0088] Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxy phenyl)propionate] (AntiOx 10 manufactured by NOF corporation)

(Metal Deactivator)

[0089] Benzotriazole derivative (BASF Corporation, IRGAMET39)

(Evaluation of Lubricating Oil Composition)

[0090] The following evaluation was made about the thus prepred lubricating oil composition as follows, and the results were shown in tables 2 and 3.

(Biodegradability Test)

[0091] Biodegradability test was performed according to OECD 301C. In the case that the biodegradability measured by the test is 60 percent or higher, it is qualified standards as a biodegradable lubricant oil, according to ECO MARK OFFICE of Public Interest Incorporated foundation Japan Environment Association. According to this test, it is marked as Q in the case that the biodegradability is 70 percent or higher, it is marked as O in the case that the biodegradability is 60 percent or higher and below 70 percent, and it is marked as x in the case that the biodegradability is below 60 percent,

(Toxicity and Accumulation Property in an Aquatic Life)

[0092] The toxicity test in an aquatic life was performed according to OECD 201, 202 and 203. Further, according to OECD117, the test of accumulation property in an aquatic life was performed. According to the test, in the case of the toxicity test, that of EC50 (or LC50)>100 mg/L is rated as qualified, and in the case of the accumulation property test, that of log Kow<3 or log Kow>7 was rated as qualified.

[0093] As to the evaluation results, that rated as qualified in both tests was represented as O, and that rated as disqualified in either or both of the tests was represented as x.

(Stability Against Oxidation: RPVOT Test)

[0094] The test of stability against oxidation of the lubricating oil (RPVOT) was performed, based on Japanese industrial standards JIS K2514-3 (2013). As the numerical value described in the table is larger, the oxidation stability is better.

[0095] According to the test, 2 is described in the case of 150 minutes or more, O is described in the case of 100 minutes or more and less than 150 minutes, and x is described in the case of less than 100 minutes.

(Shell Four-Ball Load Bearing Capacity Test)

[0096] Using a high-speed Shell four-ball testing machine, the maximum non-seizure load was measured according to ASTM D2783. As the maximum non-seizure load described in the table is larger, the extreme pressure property is better.

[0097] According to the test, is described in the case of 160 kgf or larger, O is described in the case of 100 kgf or larger and less that 160 kgf and x is described in the case of less than 100 kgf.

(Demulsibility)

[0098] The test of demulsibility was performed according to Japanese Industrial Standards JIS K 2520. As the emulsified layer is lesser is a shorter time period, the demulsibility becomes better.

[0099] According to the test, is described in the case that the time period for the emulsified layer reaching 3 mL or less is shorter than 30 minutes, O is described in the case that the time period is 30 minutes and longer and shorter than 60 minutes, and x is described in the case that the time period for the emulsified layer reaching 3 mL or less is 60 minutes or longer or that the emulsified layer does not reach 3 ml or less even after 60 minutes or longer.

(Stability Against Shearing when Water is Added)

[0100] After 10 wt % of water was added to the lubricating oil composition, the dependency of viscosity at 40 C. on the shearing rate was measured by a rheometer and CP (Cone plate) in a range of 1 to 1,000(1/s). The TI value is calculated as a ratio of the viscosities at shearing rates of 1(1/s) and 100(1/s) [TI value=viscosity at a shearing rate of 100 (1/s)/viscosity at a shearing rate of 1(1/s)]. As the TI value is nearer to 1, the stability against shearing is higher.

[0101] According to the test, O is described in the case that the TI value is 0.90 or higher, and x is described in the case that the TI value is less than 0.90.

TABLE-US-00001 TABLE 1 A1 A2 A1 Molar percentage (a) pentaerythritol 23.5 25.6 31.1 of each constituent (b) oleic acid 69.8 61.5 62.5 component (c) adipic acid 6.8 12.8 6.3 (molar %) Molar ratio of (c)mol %/(b)mol % 0.097 0.208 0.101 each constituent (c)mol %/(a)mol % 0.29 0.50 0.20 component (b)mol %/(a)mol % 2.97 2.40 2.01 Physical values Acid value 1.1 2.0 0.5 (mg KOH/g) Hydroxyl value 28 41 132 (mg KOH/g) Kinematic viscosity at 110.4 133.2 120.0 40 C. (mm2/s) Kinematic viscosity at 17.3 19.3 16.1 100 C. (mm2/s) Viscosity index 172 165 144 Flash point 317 328 326 ( C., COC method)

TABLE-US-00002 TABLE 2 Inventive examples 1 2 3 4 5 Base oil Ester compound A1 A2 A1 A1 A2 Mass parts 100 100 100 100 100 Additives Extreme pressure (B)mono-dihexyl phosphate-C11-14 0.5 0.5 0.5 1.2 0.2 (mass parts) agent branched alkyl amine salt Branched butyl phosphate-C12-14 0 0 0 0 0 branched alkyl amine salt Dibenzyl disulfide 0 0 0 0 0 Amine based oxidation (C) N-[4-(1,1,3,3-tetramethyl 0.7 1.5 0.5 0.7 0.7 preventing agent butyl) phenyl-1-naphthylamine Phenol based oxidation (D) pentaerythritol tetrakis [3-(3,5-di- 0.7 1.5 0.5 0.7 0.7 preventing agent tert-butyl-4-hydroxyphenyl) propionate] Metal deactivator Benzotriazole derivative 0.005 0.005 0.005 0.005 0.005 Performance Biodegradability test Toxicity and accumulation property in aquatic life Stability against oxidation (RPVOT) (minutes) (193) (382) (140) (231) (158) Extreme pressure property (Seizuer load) (kgf) Q(160) (160) (160) (200) (126) Demulsibility Stability against shearing upon addition of water (TI value) (0.95) (0.96) (0.94) (0.98) (0.92)

TABLE-US-00003 TABLE 3 Comparative Examples 1 2 3 4 5 Base oil Ester compound A1 A1 A1 A2 A1 Mass parts 100 100 100 100 100 Additives Extreme pressure (B) mono-dihexyl phosphate C11-14 0.5 2.0 0 0 0.5 (mass parts) agent branched alkyl amine salt Branched butyl phosphate-C12-14 0 0 0.5 0 0 branched alkyl amine salt Dibenzyl disulfide 0 0 0 0.5 0 Amine based oxidation (C) N-[4-(1,1,3,3-tetramethyl 0.7 0.7 0.7 0.7 0 preventing agent butyl) phenyl-1-naphthylamine Phenol based oxidation (D) pentaerythritol tetrakis [3-(3,5-di- 0.7 0.7 0.7 0.7 0 preventing agent tert-butyl-4-hydroxyphenyl) propionate] Metal deactivator Benzotriazole derivative 0.005 0.005 0.005 0.005 0.005 Performance Biodegradability test Toxicity and accumulation property in aquatic life x Stability against oxidation (RPVOT) (minutes) (150) (268) x(65) x(90) x(21) Extreme pressure property (Seizure load) (kgf) (100) (200) (100) x(80) (160) Demulsibility x x x Stability against shearing upon addition of water (TI value) (0.96) (0.99) x(0.66) x(0.54) (0.94)

[0102] As described in the inventive examples 1 to 5 in table 2, by blending the lubricating oil composition of the present invention with the respective additives, the biodegradability, lubricating property (extreme pressure property), stability against oxidation and demulsibility are proved to be excellent, the toxicity and accumulation property in an aquatic life are proved to be low, and the stability against shearing is proved to be excellent even in the presence of water.

[0103] As shown in table 3, according to the comparative example 1, the ester compound A1 is contained instead of the ester compound A1. As the molar percentage of the constituent component (a) is high and the hydroxyl value of the ester compound A1 is high, the demulsibility of the lubricating oil composition is low.

[0104] According to the comparative example 2, as the content of (B) mono-dihexyl phosphate C11-14 branched alkyl amine salt is too high, the toxicity and accumulation property in an aquatic life is high and demulsibility is low.

[0105] According to the comparative example 3, as branched butyl phosphate-C12-14 branched alkyl amine salt is contained instead of (B) mono-dihexyl phosphate C11-14 branched alkyl amine salt, the stability against oxidation, demulsibility and stability against shearing upon the addition of water of the lubricant oil composition are low.

[0106] According to the comparative example 4, as dibenzyl disulfide is contained instead of (B) mono-dihexyl phosphate C11-14 branched alkyl amine salt, the stability against oxidation, lubricating property (extreme pressure property) and stability against shearing upon the addition of water of the lubricating oil composition are low.

[0107] According to the comparative example 5, as the amine-based and phenol-based oxidation preventing agents are not contained, the stability against oxidation of the lubricant oil composition is low.

INDUSTRIAL APPLICABILITY

[0108] The lubricant oil composition of the present invention is excellent in biodegradability, lubricating property (extreme pressure property), stability against oxidation and demulsibility, has low toxicity and accumulation property in an aquatic life and has excellent stability against shearing even in the presence of water. Thus, it can be appropriately applied for a bearing oil, hydraulic oil, gear oil or the like, and may appropriately applied particularly for a stern tube bearing oil, thruster oil or the like used in ocean areas.