LUBRICANT POLYMERS

Abstract

A method of increasing the spreading of a lubricant on the liner surface after it's delivery, wherein the method comprises preparing the lubricant compositions comprising copolymers of monomers (A) selected from C6-C10 alkyl methacrylate monomers, and monomers (B) selected from C10-C18 alkyl methacrylate monomers, and a base oil or comprising a copolymer obtained by combining at least monomers (A) selected from C6-C10 alkyl methacrylate monomers, and monomers (B) selected from C10-C18 alkyl methacrylate monomers in a mixture and co-polymerizing the monomers for increasing the spreading and/or the self-spreading of the lubricant on the cylinder liner surface after its delivery.

Claims

1.-15. (canceled)

16. A method of increasing the spreading of a lubricant on the liner surface after its delivery, wherein said method comprises preparing a lubricant composition comprising: a copolymer of alkyl methacrylate monomers, wherein said alkyl methacrylate monomers comprise at least: a. Monomers (A) selected from C6-C10 alkyl methacrylate monomers, b. Monomers (B) selected from C10-C18 alkyl methacrylate monomers, a base oil.

17. The method according to claim 16, wherein the copolymer is obtained by combining at least a. Monomers (A) selected from C6-C10 alkyl methacrylate monomers, b. Monomers (B) selected from C10-C18 alkyl methacrylate monomers, in a mixture and co-polymerizing the monomers, and a base oil.

18. The method according to claim 16, wherein monomers (A) and monomers (B) represent at least 75% by weight of the total weight of monomers used to prepare the copolymer.

19. The method according to claim 16, wherein the weight ratio of monomers (B) to monomers (A) in the copolymer is 99:1 to 10:90.

20. The method according to claim 16, wherein monomers (A) are branched.

21. The method according to claim 20, wherein monomers A are 2-ethyl hexyl methacrylate.

22. The method according to claim 16, wherein monomers (B) are linear.

23. The method according to claim 22, wherein monomers (B) are a mixture of C10 alkyl methacrylate, C12 alkyl methacrylate, C14 alkyl methacrylate, C16 alkyl methacrylate and C18 alkyl methacrylate.

24. The method according to claim 16, wherein the copolymer is a copolymer of a mixture of C10 alkyl methacrylate, C12 alkyl methacrylate, C14 alkyl methacrylate, C16 alkyl methacrylate and C18 alkyl methacrylate, and a C8 alkyl methacrylate.

25. The method according to claim 16, wherein the mass ratio of the monomers (B) to monomers (A) is from 90:10 to 80:20.

26. The method according to claim 16, wherein the quantity of copolymer is from 0.01% to 10% by weight relative to the total weight of the lubricant composition.

27. The method according to claim 16, wherein the lubricant further comprises an optional additive chosen amongst a neutral detergent, an overbased detergent, an anti-wear additive, a fatty amine soluble in lubricant, a polymer, a dispersing additive, an anti-foaming additive or a mixture thereof.

28. The method according to claim 16, wherein the lubricant composition is a marine lubricant having a BN determined according to the standard ASTM D-2896 of at most 50 milligrams of potassium hydroxide per gram of the lubricant composition.

29. The method according to claim 16, wherein the lubricant composition is a marine lubricant having a BN determined according to the standard ASTM D-2896 of at least 50 milligrams of potassium hydroxide per gram of the lubricant composition.

30. The method according to claim 16, for two-stroke marine engines.

31. The method according to claim 16 for further increasing the self-spreading of the lubricant on the cylinder liner surface after its delivery.

32. The method as defined claim 16 for increasing the self-spreading of the lubricant on the cylinder liner surface after its delivery.

Description

FIGURES

[0143] FIG. 1: variation of the spreadability of different lubricant compositions versus the number of cycles.

Curve () represents the evolution of the spreadability of a first composition according to the invention (composition C3). Curve () represents the evolution of the spreadability of a second composition according to the invention (Composition C4). Curve () represent the evolution of the spreadability of a reference lubricant composition (Composition R).

EXAMPLES

[0144] C10-C18 alkyl methacrylate as used in Examples 1 and 2 was provided as methacrylic ester 13.0, which is commercially available as VISIOMER Terra C13,0-MA from Evonik Industries.

Example 1

[0145] To a 4-neck 2000 mL flask equipped with an overhead stirrer, a condenser, a thermocouple and a subsurface nitrogen purge was added 645.5 g of water and 8.7 g of Aerosol OT. The stirring was turned up to 200 rpm and the subsurface nitrogen purge was started. To the reaction mixture was then added 270.0 g of C10-C18 alkyl methacrylate, 30.0 g of 2-ethylhexyl methacrylate and 129.9 g of acetone. The reaction was heated up to 43 C. by using a temperature controlled water batch set at 45 C. Once the reaction reached 43 C., 0.04 g of t-butyl hydroperoxide in 7.5 g of water was added. After 5 minutes, 0.29 g of sodium ascorbate dissolved in 7.5 g of water and 0.60 g of a 0.25% solution of iron sulfate hexahydrate was added. The nitrogen purge was then changed to a nitrogen blanket. The reaction was held an additional 5 hours, cooled to room temperature and isolated.

Example 2

[0146] To a 4-neck 2000 mL flask equipped with an overhead stirrer, a condenser, a thermocouple and a subsurface nitrogen purge was added 645.5 g of water and 8.7 g of Aerosol OT. The stirring was turned up to 200 rpm and the subsurface nitrogen purge was started. To the reaction mixture was then added 240.0 g of C10-C18 alkyl methacrylate, 60.0 g of 2-ethylhexyl methacrylate and 129.9 g of acetone. The reaction was heated up to 43 C. by using a temperature controlled water batch set at 45 C. Once the reaction reached 43 C., 0.04 g of t-butyl hydroperoxide in 7.5 g of water was added. After 5 minutes, 0.29 g of sodium ascorbate dissolved in 7.5 g of water and 0.60 g of a 0.25% solution of iron sulfate hexahydrate was added. The nitrogen purge was then changed to a nitrogen blanket. The reaction was held an additional 5 hours, cooled to room temperature and isolated.

Preparation of a Test Lubricant Composition Comprising 5% Solids Solution of Copolymer in Oil

[0147] To a 4-neck 1000 mL flask equipped with an overhead stirrer, a Barrett distillation trap with a condenser and a thermocouple was added an amount of the emulsion of any of Examples 1 and 2 to give 20.0 g of polymer. Neutral Solvent 600 was then added to bring the total up to 400.0 g, followed by 150.0 g of toluene. The stirring was turned up to 200 rpm and the mixture was brought up to reflux. As water condensed in the Barrett trap it was drained off. Once the water stopped overflowing, the contents of the reactor were brought up to 130 C. to distill of a majority of the toluene. The remaining material was transferred to a 1000 mL single neck round bottom and concentrated at vacuum with a bath at 60 C. until the material reached a constant weight.

[0148] The test lubricant was submitted to the above disclosed finger pull test.

Method for Determining Molecular Weight and Radius of Gyration

[0149] The Molecular Weight and Radius of Gyration of the polymer samples, supplied at 5% solids in base oil, was determined by the procedure outlined below:

[0150] Eluant: HPLC Grade Tetrahydrofuran stabilized with 0.01% Butylated Hydroxytoluene

[0151] Column: Phenogel Guard Column 100A 10 um 300 mm7.8 mm.

[0152] Flow Rate: 0.50 ml/min.

[0153] Detectors: Wyatt Dawn Heleos-II MultiAngle Light Scattering (MALS) at 663 nm and room temperature and Wyatt Optilab T-rEX Refractive Index Detector at 658 nm and 40 C.

[0154] Pump/Autosampler: Agilent 1100 Isocratic HPLC Pump and Autosampler

[0155] Column Compartment: 40 C.

[0156] Standards: There were no standards directly correlated with the analysis, but the Heleos-II MALS calibration constant was established with Toluene and the Optilab T-rEX calibration constant was established with NaCl in water. The 17 angles on the Heleos-II were normalized with a narrow range polystyrene standard at 28,500 daltons Molecular Weight and the detector delay volume was adjusted with the same standard.

[0157] Sample Preparation: The samples were prepared by gravimetrically diluting about 8.0 mg of sample with about 5.0 g of tetrahyrofuran. The actual concentration of polymer in mg/ml was calculated based on the density of tetrahydrofuran (0.889 g/ml) and the percentage solids in the sample solutions (5.0%).

[0158] Injection: 50 l.

[0159] Run time: 20 minutes.

[0160] Software: Wyatt Astra Version 6.1.4.25.

[0161] Calculations: The Astra software provides several choices of formalisms and exponent order to fit the data. All samples were fit with a 2.sup.nd order Berry. The angles used were adjusted to give the best fit, using a minimum of 13 angles and up to the maximum of 17. The dn/dc was calculated from the refractive index data assuming 100% recovery. The software reported the average Molecular Weight as Mw and the average Root Mean Square Radius of Gyration as Rg. The results are shown in Table 1.

TABLE-US-00002 TABLE 1 FeSO4.sup.2 Example LMA.sup.1 2-EHMA.sup.1 Acetone.sup.2 TBHP.sup.2 Ascorbate.sup.2 (0.25%) 1 90 10 43.3 0.013 0.098 0.20 2 80 20 43.3 0.013 0.098 0.20 NS600 Base Oil 5% S NS600 Aerosol Mw Peak 1 Mw Peak 2 Rg Peak 1 Rg Peak 2 viscosity Example OT.sup.2 (10.sup.6 g/mol) (10.sup.6 g/mol) (nm) (nm) [mPa .Math. s] 1 2.90 133 6.4 140 108 3610 2 2.90 133 7.0 135 104 2152 NS600 300 Base Oil .sup.1Percentage of monomer as a mass percent of the total amount of monomer .sup.2Parts per hundred based on the total amount of monomer LMA = C10-C18 alkyl methacrylate; 2-EHMA = 2-ethylhexyl methacrylate.

Example Lubricant Compositions

[0162] Lubricant compositions C1, C2, C3 and C4 have been prepared with the following compounds: [0163] lubricating base oil 1: Group I Mineral oils or brightstock of density between 895 and 915 kg/m.sup.3, [0164] lubricating base oil 2: Group I mineral oils, in particular called 600R viscosity at 40 C. of 120 cSt measured according to ASTM D7279, [0165] detergent package 1 comprising an anti-foaming agent, [0166] detergent package 2, [0167] fatty amine, [0168] polymer from example 2.

[0169] The compositions C1, C2, C3 and C4 are disclosed in Table 2. The percentages disclosed in Table 2 correspond to weight percent.

TABLE-US-00003 TABLE 2 Composition C1 C2 C3 C4 Base oil 1 18.0 18.0 10.0 Base oil 2 54.6 49.6 72.50 64.3 Detergent package 1 26.9 26.9 Detergent package 2 25.5 25.5 Fatty amine 0 5.0 Polymer from example 2 0.5 0.5 2 0.2

Measure of the Spreadability of the Lubricant Compositions

[0170] The value of the spreadability of several lubricant oil compositions is determined by submitting a drop of each composition to a repeated ring movement at a given temperature, surface roughness and radial load and by determining the surface occupied by the drop at the end of the experiment.

Materials:

Compositions According to the Invention:

[0171] The compositions according to the invention are Composition C3 and Composition C4 disclosed in Table 2.

Reference Composition:

[0172] Composition R: lubricating oil commercially available as TALUSIA HR70 from TOTAL.

Additive:

[0173] Fluorescein, commercially available from Sigma Aldrich.

Protocol:

[0174] The spreadability of the oil compositions is determined by using a Liner Guardian Test Rig.

[0175] The Liber Average Roughness of the support has been determined by dividing the surface of the support in elemental quadrangles thus defining a matrix. The roughness of each quadrangle of the matrix has been then determined by using a rugosimeter. The average value for the Roughness of the support has been calculated.

[0176] The radial load value has been determined by positioning a strain gauge on the structure supporting the ring.

[0177] The strain gauge was calibrated before the experiments by using weights of known value.

[0178] The temperature of the liner is set by using electrical resistances and was measured at two different locations (at opposite ends of the structure). The Liner temperature considered is the average value.

[0179] Temperature and radial load value are controlled all along the experiments by a LabVIEW program in order to ensure that the operational conditions would remain constant. The Experimenter could thus check the variables value at any time and, if necessary, make any adjustment to the apparatus so that radial load and temperature would remain constant at the required value. The radial load can be adjusted by actuating a valve situated on the strain gauge.

[0180] Test parameters are disclosed in Table 3.

TABLE-US-00004 TABLE 3 Compositions C3 C4 R Average oil drop weight (mg) 11.2 11.1 11.0 Radial Load (N/cm.sup.2) 4 4 4 Ring speed (cm/s) 2.9 2.9 2.9 Liner temperature ( C.) 70 70 70 Average Surface Roughness of the support (m) 0.72 0.72 0.72

[0181] In order to enhance the visibility of the oil compositions under black light, fluorescein is added to each oil compositions in a content of 0.10% by weight, based on the total oil composition weight.

[0182] At the end of the trails, images of the oil compositions spreading profiles are collected by using a dark (UV) light of at most 490 nm and a high-resolution camera.

[0183] Collected images are then analysed with MATLAB image processing tools. The script developed acts on the following sequence:

a) Area detection and contour definition,
b) having the best fit parameters, it was possible to determine the area of each profile; the script would convert the area in pixels to cm.sup.2,
c) the output stored was the area of the oil composition drop in cm.sup.2.

[0184] The spreadability of each composition is finally obtained by dividing the area occupied by the drop by the weight of the drop introduced.

[0185] Images are collected after 1, 3 and 5 cycles.

Results:

[0186] The variation of the spreadability of the compositions C3, C4 and R after several cycles is represented on FIG. 1.

Curve () relates to composition C3. Curve () relates to composition C14 and curve () relates to composition R.

[0187] After 1 cycle, the highest value of the spreadability is observed for composition C4 with about 2.40 cm.sup.2/mg.

Spreadability of compositions C3 and R is similar and of about respectively 1.40 cm.sup.2/mg and 1.37 cm.sup.2/mg.

[0188] After 3 cycles, the highest value of spreadability is still observed for composition C4 with about 2.96 cm.sup.2/mg.

Spreadability of compositions C3 and R is similar and of about respectively 1.90 cm.sup.2/mg and 1.82 cm.sup.2/mg.

[0189] After 5 cycles, the highest value of spreadability is still observed for composition C4 with about 2.96 cm.sup.2/mg.

Spreadability of composition C3 is about 2.51 cm.sup.2/mg and spreadability of composition R is about 1.88 cm.sup.2/mg.

[0190] We observed that that lubricant compositions according to the invention have an improved value of spreadability after 3 and 5 cycles when compared to the reference lubricant composition.