Lubricant additive, lubricant additive composition, and lubricating oil composition containing the same

Abstract

A lubricant additive capable of imparting various functions to a lubricant base oil contains an ester compound (A) represented by formula (1) and an ester compound (B) represented by formula (2). (A):(B) being a mass ratio of the ester compound (A) to the ester compound (B) is 99:1 to 80:20.

Claims

1. A lubricant additive, comprising: an ester compound (A) represented by formula (1), ##STR00007## wherein R.sup.1 represents an alkylene group or an alkenylene group having 2 carbon atoms, R.sup.2 represents an alkyl group or an alkenyl group having 4 to 22 carbon atoms, and M represents a hydrogen atom or tertiary ammonium cations in which a saturated or unsaturated hydrocarbon group having 1 to 24 carbon atoms is bonded to a nitrogen atom; and an ester compound (B) represented by formula (2), ##STR00008## wherein R.sup.3 represents an alkylene group or an alkenylene group having 2 carbon atoms, and R.sup.4 and R.sup.5 each independently represent an alkyl group or an alkenyl group having 4 to 22 carbon atoms, wherein (A):(B) being a mass ratio of the ester compound (A) and the ester compound (B) is 99:1 to 80:20.

2. A lubricant additive composition, comprising: the lubricant additive according to claim 1; and zinc dithiophosphate (C) represented by formula (3), ##STR00009## wherein R.sup.6 to R.sup.9 each independently represent a hydrocarbon group having 1 to 24 carbon atoms, wherein a content of the zinc dithiophosphate (C) is 1 to 1000 parts by mass with respect to a total content of the ester compound (A) and the ester compound (B) being 100 parts by mass.

3. A lubricating oil composition, comprising: 70 to 99.99 mass% of a lubricant base oil; and 0.01 to 30 mass% of the lubricant additive according to claim 1.

4. A lubricating oil composition, comprising: 70 to 99.99 mass% of a lubricant base oil; and 0.01 to 30 mass% of the lubricant additive composition according to claim 2.

Description

EXAMPLES

(1) Below, the present invention will be described in more detail with reference to examples and comparative examples.

(2) A production example of the ester compound (A) represented by formula (1) is described in Synthesis Example 1 below, and a production example of the ester compound (B) represented by formula (2) is described in Synthesis Example 2 below. Further, in Formulation Example 1 below, a production example of an additive 1 composed of the ester compound (A) represented by formula (1) and the ester compound (B) represented by formula (2) is described.

Synthesis Example 1, Compound (A-1) of Formula (1)

(3) A thermometer and a nitrogen introduction tube were inserted into a 1 L four-neck flask, and oleyl alcohol (250 g, 0.93 mol) and succinic anhydride (93.2 g, 0.93 mol) were introduced into the flask and allowed to react at 120° C. using a mantle heater. The reaction was terminated when the decrease in acid value per hour was 0.5 mg KOH/g or less, and the mixture was cooled to room temperature. Next, 200.6 g (0.93 mol) of dimethyllaurylamine was added, and the mixture was stirred and mixed at 25° C. for 1 hour to obtain 543.8 g (0.93 mol) of compound (A-1) of formula (1).

(4) Compounds (A-2), (A-3), (A-4), and (A-5) of formula (1) shown in Table 1 were synthesized by using other compounds instead of oleyl alcohol, succinic anhydride, and dimethyllaurylamine in Synthesis Example 1, as appropriate, and performing operation according to Synthesis Example 1.

(5) TABLE-US-00001 TABLE 1 Compound R.sup.1 R.sup.2 M A-1 Ethylene Oleyl Dimethyllaurylammonium A-2 Ethenylene 2-ethylhexyl Dimethyllaurylammonium A-3 Ethylene Isotridecyl Dimethyllaurylammonium A-4 Ethylene Oleyl Hydrogen atom A-5 Ethylene Ethyl Dimethyllaurylammonium

Synthesis Example 2, Compound (B-1) of Formula (2)

(6) A thermometer and a nitrogen introduction tube were inserted into a 500 ml four-neck flask, oleyl alcohol (300 g, 1.12 mol) and succinic anhydride (55.9 g, 0.56 mol) were introduced into the flask and allowed to react at 240° C. using a mantle heater. The reaction was terminated when the decrease in acid value per hour was 0.5 mg KOH/g or less, and 345.9 g (0.56 mol) of compound (B-1) of formula (2) was obtained.

(7) Compounds (B-2), (B-3), and (B-4) of formula (2) shown in Table 2 were synthesized by using other compounds instead of oleyl alcohol and succinic anhydride in Synthesis Example 2, as appropriate, and performing operation according to Synthesis Example 2.

(8) TABLE-US-00002 TABLE 2 Compound R.sup.3 R.sup.4 R.sup.5 B-1 Ethylene Oleyl Oleyl B-2 Ethenylene 2-ethylhexyl 2-ethylhexyl B-3 Ethylene Isotridecyl Isotridecyl B-4 Ethylene Ethyl Ethyl

Formulation Example 1, Additive 1

(9) A thermometer and a nitrogen introduction tube were inserted into a 1 L four-neck flask, and compound (A-1) (500 g, 0.85 mol) synthesized in Synthesis Example 1 and compound (B-1) (10.3 g, 0.017 mol) synthesized in Synthesis Example 2 were stirred and mixed at 25° C. for 1 hour to obtain 510.3 g of additive 1.

(10) Additives 2 to 8 shown in Table 3 were obtained by using a blending ratio different from the blending ratio of compound (A-1) of formula (1) and compound (B-1) of formula (2) used in Formulation Example 1, as appropriate, and performing operation according to Formulation Example 1.

(11) TABLE-US-00003 TABLE 3 Blending ratio (mass ratio) Ester compound Ester compound (A) of formula (1) (B) of formula (2) Additive A-1 A-2 A-3 A-4 A-5 B-1 B-2 B-3 B-4 1 98 — — — — 2 — — — 2 — 98 — — — — 2 — — 3 92 — — — — 8 — — — 4 — — — 98 — 2 — — — 5 — — 98 — — — — 2 — 6 100  — — — — — — — — 7 75 — — — — 25  — — — 8 — — — — 98 — — — 2

Formulation Example 2, Preparation of Lubricating Oil Composition (1)

(12) 0.5 mass % of each of the additives 1 to 8 mentioned above was blended to the lubricant base oil (poly-α-olefin, kinematic viscosity (40° C.): about 50 mm.sup.2/s) to obtain lubricating oil compositions (1-1) to (1-8) of Examples (1-1) to (1-5) and Comparative Examples (1-1) to (1-3). The obtained lubricating oil compositions (test oils) were subjected to the evaluation tests described below. The evaluation results of Examples (1-1) to (1-5) are shown in Table 4 below, and the evaluation results of Comparative Examples (1-1) to (1-3) are shown in Table 5 below.

Wear Resistance Test

(13) The wear resistance was evaluated by using an SRV test instrument (Schwingungs Reihungundund Verschleiss test instrument type 4, manufactured by OPTIMOL). The SRV test was performed with a ball/disc, and each test piece was made of SUJ-2. The test conditions were a test temperature of 150° C., a load of 100 N, an amplitude of 1 mm, and a frequency of 50 Hz, and the wear scar diameter was measured after a test time of 25 minutes had elapsed.

(14) The evaluation results were assessed as good: wear scar diameter of less than 350 μm, acceptable: 350 μm or more and less than 400 μm, and unacceptable: 400 μm or more.

Test of Friction Reducing Properties

(15) The friction coefficient was evaluated by using a multifunctional friction and wear tester (UMT-TriboLab, manufactured by BRUKER). The tribology test was performed with a cylinder/disc, and each test piece was made of SUJ-2. The test conditions were a test temperature of 25° C., a load of 20 N, a rotation speed of 1000 rpm, and a measurement time of 30 seconds, the test was carried out 10 times, and the average friction coefficient was calculated.

(16) The evaluation results were assessed as good: average friction coefficient of less than 0.035, acceptable: 0.035 or more and less than 0.040, and unacceptable: 0.040 or more.

Demulsibility Test

(17) The demulsibility was evaluated. The evaluation was performed based on JIS K 2520 and the separation time of oil and water was evaluated. The evaluation results were assessed as good: separation time of less than 15 minutes or unacceptable: 15 minutes or more.

(18) Table 4 shows a relationship between the symbols in formula (2) and the compounds.

Metal Corrosion Resistance Test

(19) The copper corrosion resistance was evaluated as the metal corrosion resistance. A copper wire cut to a length of 4 cm was polished with a P150 polishing cloth. 2 ml of test oil was placed into a 5 ml screw cap tube, the copper wire was immersed therein, and the tube was heated at 100° C. for 3 hours. The state of the surface of the copper wire before and after the test was compared to evaluate whether corrosion had occurred.

(20) The evaluation results were assessed as good: no corrosion occurred and unacceptable: corrosion occurred.

(21) TABLE-US-00004 TABLE 4 Example 1-1 1-2 1-3 1-4 1-5 Additive 1 2 3 4 5 Lubricating oil 1-1 1-2 1-3 1-4 1-5 composition (1) Wear Wear scar Good Good Acceptable Acceptable Acceptable resistance diameter (310) (330) (370) (370) (390) (μm) Friction Friction Good Good Good Acceptable Acceptable reducing coefficient (0.030) (0.032) (0.034) (0.039) (0.039) properties Demulsibility Good Good Good Good Good Metal corrosion Good Good Good Good Good resistance

(22) TABLE-US-00005 TABLE 5 Comparative Example 1-1 1-2 1-3 Additive 6 7 8 Lubricating oil composition (1) 1-6 1-7 1-8 Wear Wear scar Good (330) Unacceptable Unacceptable resistance diameter (μm) (550) (570) Friction Friction Good (0.033) Unacceptable Unacceptable reducing coefficient (0.050) (0.060) properties Demulsibility Unacceptable Good Good Metal corrosion resistance Good Good Unacceptable

(23) As can be clearly understood from the results shown in Table 4, the additives 1 to 5 according to the present invention are capable of imparting excellent wear resistance, friction reducing properties, demulsibility, and metal corrosion resistance to a lubricant base oil. Further, the additives 1 to 5 do not contain metal components such as zinc, and thus, the lubricating oil compositions (1-1) to (1-5) of Examples (1-1) to (1-5) containing these additives 1 to 5 do not generate ash components when being used, so that filters such as DPF are less likely to be clogged. Further, the additives 1 to 5 do not contain phosphorus atoms or sulfur atoms, so that the influence on a three-way catalyst from using the lubricating oil compositions (1-1) to (1-5) of Examples (1-1) to (1-5) is reduced.

(24) Next, an example of preparing an additive composition containing the compounds (A-1) and (A-4) of formula (1) shown in Table 1, compound (B-1) of formula (2) shown in Table 2, and zinc dithiophosphate (C) described below is described in Formulation Example 3 below. Further, an example of preparing the lubricating oil composition (2) containing the additive composition prepared in Formulation Example 3 is described in Formulation Example 4 below.

Zinc Dithiophosphate: Compounds (C-1) and (C-2) of Formula (3)

(25) LUBRIZOL 677A (alkyl group: branched hexyl group) and LUBRIZOL 1395 (alkyl groups: linear butyl group and linear pentyl group) manufactured by Lubrizol Corp. were used as zinc dithiophosphate. Compound (C-1) is LUBRIZOL 677A and compound (C-2) is LUBRIZOL 1395.

(26) Table 6 shows a relationship between the symbols in formula (3) and the compounds.

(27) TABLE-US-00006 TABLE 6 Compound R.sup.6 R.sup.7 R.sup.8 R.sup.9 C-1 Branched hexyl group C-2 Linear butyl group and linear pentyl group

Formulation Example 3, Preparation of Additive Compositions

(28) A thermometer and a nitrogen introduction tube were inserted into a four-neck flask (300 mL to 1 L), and the additives shown in Table 7 were stirred and mixed at 25° C. for 1 hour to obtain additive compositions 1 to 8.

(29) TABLE-US-00007 TABLE 7 Additive blending amount (g) Additive Compound Compound Compound Blending ratio com- (A) (B) (C) (mass ratio) position A-1 A-4 B-1 C-1 C-2 A:B (A + B):C 1 98 — 2 100 — 98:2 100:100 2 98 — 2  25 — 98:2 100:25  3 98 — 2 400 — 98:2 100:400 4 98 — 2 — 100 98:2 100:100 5 — 98 2 100 — 98:2 100:100 6 100  — — 100 — 100:0  100:100 7 75 — 25  100 —  75:25 100:100 8 — — — 100 — —  0:100

Formulation Example 4, Preparation of Lubricating Oil Composition (2)

(30) The additive compositions 1 to 8 of Table 7 were blended with the lubricant base oil (poly-α-olefin, kinematic viscosity (40° C.): about 50 mm.sup.2/s) to obtain lubricating oil compositions (2-1) to (2-9) shown in Table 8.

(31) TABLE-US-00008 TABLE 8 Additive composition Lubricating oil Base oil 1 2 3 4 5 6 7 8 composition (2) (PAO) Blending amount (wt %) 2-1 99.5 0.5 — — — — — — — 2-2 — 0.5 — — — — — — 2-3 — — 0.5 — — — — — 2-4 — — — 0.5 — — — — 2-5 — — — — 0.5 — — — 2-6 — — — — — 0.5 — — 2-7 — — — — — — 0.5 2-8 — — — — — — — 0.5 2-9 99   — — — — — — — 1

(32) The obtained lubricating oil compositions (test oils) were subjected to the evaluation tests described below. The evaluation results are shown in Tables 9 and 10.

Load Bearing Capacity Test

(33) The seizure load was evaluated with a Shell four-ball tester. The test piece was made of

(34) SUJ-2. The test conditions were a test temperature of 25° C., a rotation speed of 1800 rpm, and a test time of 10 seconds, and loads of 50 kg, 63 kg, 80 kg, 100 kg, 126 kg, 160 kg, and 200 kg were applied in this order. In the test, a load at which phenomena such as a sudden increase in friction torque and generation of abnormal noise occurred, and seizure marks were generated on the abrasion surface was defined as the seizure load.

(35) The evaluation results were assessed as good: seizure load of 160 kg or more, acceptable: 126 kg or more and less than 160 kg, and unacceptable: less than 126 kg.

Test of Friction Reducing Properties

(36) The friction coefficient was evaluated by using an SRV test instrument (Schwingungs Reihungundund Verschleiss test instrument type 4, manufactured by OPTIMOL). The SRV test was performed with a cylinder/disc, and each test piece was made of SUJ-2. The test conditions were a test temperature of 100° C., a load of 200 N, an amplitude of 1 mm, and a frequency of 300 Hz, and the friction coefficient was measured after a test time of 60 minutes had elapsed.

(37) The evaluation results were assessed as good: friction coefficient of less than 0.18, acceptable: 0.18 or more and less than 0.2, and unacceptable: 0.2 or more.

Demulsibility Test

(38) The demulsibility was evaluated. The evaluation was performed based on JIS K 2520 and the separation time of oil and water was evaluated. The evaluation results were assessed as good: separation time of less than 10 minutes, acceptable: 10 minutes or more and less than 15 minutes, and unacceptable: 15 minutes or more.

(39) TABLE-US-00009 TABLE 9 Example 2-1 2-2 2-3 2-4 2-5 Lubricating oil composition (2) 2-1 2-2 2-3 2-4 2-5 Load bearing Seizure load Good (200) Good (160) Good (160) Acceptable Acceptable capacity (kg) (126) (126) Friction reducing Friction Good Good Acceptable Good Acceptable properties coefficient (μ) (0.166) (0.167) (0.181) (0.167) (0.190) Demulsibility Separation Good Good Good Good Acceptable time (minutes) (5 minutes) (5 minutes) (5 minutes) (5 minutes) (10 minutes)

(40) TABLE-US-00010 TABLE 10 Comparative Example 2-1 2-2 2-3 2-4 Lubricating oil composition (2) 2-6 2-7 2-8 2-9 Load bearing Seizure load (kg) Good Unacceptable Unacceptable Acceptable capacity (160) (63) (100) (126) Friction reducing Friction Good Unacceptable Unacceptable Unacceptable properties coefficient (μ) (0.166) (0.221) (0.233) (0.252) Demulsibility Separation time Unacceptable Good Good (5 minutes) Good (5 minutes) (minutes) (30 minutes) (5 minutes)

(41) As can be clearly understood from the results shown in Table 9, the lubricating oil compositions (2-1) to (2-5) of Examples (2-1) to (2-5) using the additive compositions 1 to 5 according to the present invention have excellent load bearing capacity, friction reducing properties, and demulsibility. That is, the additive compositions 1 to 5 are capable of imparting excellent load bearing capacity, friction reducing properties, and demulsibility to a lubricant base oil (PAO). Further, it is possible to reduce the blending amount of zinc dithiophosphate (C) with respect to the lubricant base oil (PAO), so that the generation of ash components can be reduced.

(42) On the other hand, as shown in Table 10, in Comparative Example (2-1) using the additive composition 6 not containing the ester compound (B), sufficient demulsibility was not obtained. Further, in Comparative Example (2-2) using the additive composition 7 having a high content ratio of the ester compound (B), load bearing capacity and friction reducing properties were not sufficiently obtained. Moreover, in Comparative Example (2-3) using the additive composition 8 composed only of zinc dithiophosphate (C), load bearing capacity and friction reducing properties were not sufficiently obtained, and also in Comparative Example (2-4) in which the added amount of the additive composition 8 was larger than that in Comparative Example (2-3), sufficient friction reducing properties were not obtained.

Related Applications

(43) The present application claims priority on the basis of Japanese Patent Application filed on Mar. 14, 2019 (Japanese Patent Application No. 2019-047822) and Japanese Patent Application filed on Feb. 20, 2020 (Japanese Patent Application No. 2020-027128), the entire contents of which are incorporated herein by reference.