Lubricant and method of preparing the same

Abstract

A lubricant, including, by weight: 80-85 parts of a base oil; 1-2 parts of a methyl-silicone oil; 1-2 parts of polymethacrylate; 2-4 parts of pentaerythritol polyisobutylene succinate; 1-2 parts of di-n-butyl phosphite; 2-3 parts of butylhydroxytoluene; 2-4 parts of an ethylene-propylene copolymer; 1-2 parts of an alkenyl succinate; and 3-5 parts of copper nanoparticles. A method of preparing the lubricant includes: adding the base oil, the methyl-silicone oil, the polymethacrylate, the ethylene-propylene copolymer, the butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure at 300-400 rpm for 3-4 hours, to yield a primary product; and adding the di-n-butyl phosphite, the pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 150-250 rpm for 2-2.5 hours.

Claims

1. A method of preparing, a lubricant, the lubricant comprising by weight: 80-85 parts of a base oil; 1-2 parts of a methyl-silicone oil per 80-85 parts of the base oil; 1-2 parts of polymethacrylate per 80-85 parts of the base oil; 2-4 parts of pentaerythritol polyisobutylene succinate per 80-85 parts of the base oil; 1-2 parts of di-n-butyl phosphite per 80-85 parts of the base oil; 2-3 parts of butylhydroxytoluene per 80-85 parts of the base oil; 2-4 parts of an ethylene-propylene copolymer per 80-85 parts of the base oil; 1-2 parts of an alkenyl succinate per 80-85 parts of the base oil; and 3-5 parts of copper nanoparticles per 80-85 parts of the base oil; the method comprising: adding the base oil, the methyl-silicone oil, polymethacrylate, the ethylene-propylene copolymer, butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure (NTP) at 300-400 rpm for 3-4 hours, to yield a primary product; and adding di-n-butyl phosphite, pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 150-250 rpm for 2-2.5 hours.

2. The method of claim 1, wherein the base oil comprises 70 wt. % of a synthetic oil and 30 wt. % of a trimethylolpropane ester, and the synthetic oil is a polyalphaolefin (PAO).

3. The method of claim 2, wherein the polyalphaolefin (PAO) is PAO6, PAO8, or PAO10.

4. A lubricant, comprising, by weight: 80-85 parts of a base oil; 1-2 parts of a methyl-silicone oil per 80-85 parts of the base oil; 1-2 parts of polymethacrylate per 80-85 parts of the base oil; 2-4 parts of pentaerythritol polyisobutylene succinate per 80-85 parts of the base oil; 1-2 parts of di-n-butyl phosphite per 80-85 parts of the base oil; 2-3 parts of butylhydroxytoluene per 80-85 parts of the base oil; 2-4 parts of an ethylene-propylene copolymer per 80-85 parts of the base oil; 1-2 parts of an alkenyl succinate per 80-85 parts of the base oil; and 3-5 parts of copper nanoparticles per 80-85 parts of the base oil, wherein the lubricant further comprises dioctyl dithiophosphate distributed outside the copper nanoparticles; dioctyl dithiophosphate is present in an amount of between 50% and 70%, by weight of the copper nanoparticles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1A is comparison of friction coefficients of four types of carbon films (that is, pure carbon film, Si-doped carbon film, Al-doped carbon film, H-doped carbon film) lubricated by conventional SL grade engine oil and a lubricant as described in the disclosure; and

(2) FIG. 1B is comparison of wear rates of four types of carbon films (that is, pure carbon film, Si-doped carbon film, Al-doped carbon film, H-doped carbon film) lubricated by conventional SL grade engine oil and a lubricant as described in the disclosure.

DETAILED DESCRIPTION

(3) To further illustrate, embodiments detailing a lubricant and a method of preparing the same are described below. It should be noted that the following embodiments are intended to describe and not to limit the disclosure.

Example 1

(4) Dispersion stability test of copper nanoparticles in lubricants

(5) The copper nanoparticles were modified by dioctyl dithiophosphate which accounted for 60 wt. % of the modified copper nanoparticles. The copper nanoparticles had an average particle size of 4 nm and the C.sub.8-alkyl chain modifier was distributed outside the copper nanoparticles. The copper nanoparticles were mixed with different dispersants in different additive amounts for the study of dispersion stability in lubricants.

(6) The mixtures of the copper nanoparticles and different dispersants in different additive amounts were respectively dissolved in a base oil comprising 70 wt. % of a synthetic oil and 30 wt. % of a trimethylolpropane ester, and the synthetic oil was polyalphaolefin 6 (PAO6). 24 hours later, the mixtures were centrifuged at 30° C. under 8000 rpm for 20 min. 10 mL of supernates were collected, and the transmittance thereof were measured using an UV spectrophotometer.

(7) The copper nanoparticles contained a C.sub.8-alkyl chain modifier so that they had excellent dispersion stability. However, the addition of the dispersant changed the dispersion stability of the copper nanoparticles, and the dispersant competed with the modifier to adsorb on the copper core. Once the protection of modifier disappeared, the copper nanoparticles tended to oxidize, and the color changed from brown red to grey green, deteriorating the lubricity. On the other hand, the addition of the dispersants changed the agglomeration of the copper nanoparticles, thus adversely affecting its dispersion stability in the base oil. The test results are shown in Table 1 and Table 2.

(8) TABLE-US-00001 TABLE 1 Influence of different types of dispersants on the dispersion stability of copper nanoparticles Transmittance Copper Primary after Increase ratio of nanoparticles Dispersants transmittance centrifugation transmittance Color of (Weight parts) (3 parts by weight) (%) (%) (%) lubricants 4 T151- 78.6 85.6 8.9 Greyish green Monoalkenyl succinimide 4 T152-Dialkenyl 78.6 86.4 9.9 Greyish green succinimide 4 T153- 78.5 84.8 8.0 Greyish green Multialkenyl succinimide 4 T161-High 78.8 86.7 10.0 Greyish green molecular weight (poly)succinimide 4 T171- 78.6 80.3 2.2 Brownish red Pentaerythritol polyisobutylene succinate

(9) TABLE-US-00002 TABLE 2 Influence of different weight ratios of dispersants to copper nanoparticles on the dispersion stability of copper nanoparticles Dispersant T171- Pentaerythritol Transmittance Increase ratio Copper polyisobutylene Primary after of nanoparticles succinate transmittance centrifugation transmittance Color of (Weight parts) (Weight parts) (%) (%) (%) lubricants 2 4 82.4 83.5 1.3 Brownish red 3 4 80.3 81.6 1.6 Brownish red 4 4 78.6 80.3 2.2 Brownish red 5 4 76.8 80.3 4.6 Brownish red 6 4 72.4 80.1 10.6 Brownish red 4 1 78.8 80.3 1.9 Brownish red 4 2 78.8 80.3 1.9 Brownish red 4 3 78.7 80.3 2.0 Brownish red 4 4 78.6 80.3 2.2 Brownish red 4 5 76.3 80.5 5.5 Brownish red 4 6 73.5 80.6 9.7 Brownish red

(10) The results showed that, the polyamide dispersants (T151, T152, T153, T161, produced by Xinxiang Ruifeng New Materials Co., Ltd.) competed with the modifier of the copper nanoparticles to adsorb on the copper nanoparticles, so that the copper nanoparticles were oxidized and deteriorated. However, the pentaerythritol ester dispersants (T171, produced by Lanzhou Lubo Runlan Refining Additives Co., Ltd.) can efficiently disperse the copper nanoparticles. Too many of the dispersants caused the agglomerates of the copper nanoparticles to deposit, so that the additive amount were about 2-4 weight parts.

Example 2

(11) The copper tends to oxidize the lubricant. Thus, the copper nanoparticles need to cooperate with different antioxidants to improve the antioxidant ability of the lubricant. Different antioxidants were mixed with a base oil comprising 70 wt. % of a synthetic oil and 30 wt. % of a trimethylolpropane ester, and the synthetic oil was polyalphaolefin 6 (PAO6). The antioxidant properties of the base oil were listed in Table 3.

(12) TABLE-US-00003 TABLE 3 Antioxidant properties of base oil with different antioxidants Copper Initial nanoparticles oxidation Oxidation (Weight Antioxidants (2 parts by temperature induction parts) weight) (° C.) time (min) 0 211.3 0.1 4 219.3 7.8 4 T501-2, 224.5 14.0 6-Di-tert-butyl-4-methylphenol 4 T512-Methyl 242.6 21.6 3,5-methyl-β-(3,5-di-tert- butyl-4- hydroxyphenyl)propanoate 4 T521-2,6-Di-tert-butyl- 223.7 8.7 4-(dimethylaminomethyl)phenol 4 T531- 226.3 11.9 N-Phenyl-α-naphthylamine 4 T534- 238.0 19.2 Butyl-octyl-diphenylamine

(13) The results show that, the copper nanoparticles can improve the antioxidant ability of the base oil. When mixing with the antioxidant T512, the antioxidant ability of the lubricant has been improved to the greatest extent.

Example 3

(14) The copper nanoparticles as soft metals have excellent antifriction and repair functions, but under high load and extreme pressure conditions, the copper nanoparticles cooperate with an anti-wear agent to form a synergistic effect to achieve extreme pressure lubrication effect. The anti-wear agent is a mostly organic polar compound containing sulfur, phosphorus and chlorine. The extreme pressure anti-wear ability of the lubricant is evaluated by measuring its P.sub.B (maximum nonseizure load) and P.sub.D (minimum sintering load).

(15) TABLE-US-00004 TABLE 4 Extreme pressure anti-wear ability of lubricant with different anti-wear agents Copper nanoparticles (Weight parts) Anti-wear agents (2 parts by weight) P.sub.B (N) P.sub.D (N) 0 372 568 4 813 5500 4 T301-Chlorinated paraffins 900 7080 4 T304-Acid dibutyl phosphite 945 7300 4 T305-Nitrogen-containing derivatives of 812 5560 dithiophosphoric acid 4 T306-Tricresyl phosphate 760 5100 4 T307-Thiophosphoric acid amine Salt 715 3960 4 T308-Isooctyl acid phosphate 543 2920 octadecylamine salt 4 T309-Triphenyl thiophosphate 615 4600 4 T321-Sulfurized isobutylene 342 1960 4 T322-Dibenzyl disulfide 356 2020 4 T323-Aminothioester 273 1560 4 T341-Lead naphthenate 630 6300 4 T351-DibutylCarbamodithiotic acid 730 4860 molybdenum salt 4 T352-DibutylCarbamodithiotic acid 750 5260 antimonic salt 4 T353-DibutylCarbamodithiotic acid lead 780 6430 salt

(16) The results show that, the copper nanoparticles greatly improve the extreme pressure anti-wear ability of the base oil. When mixing with the anti-wear agent T304 (dibutyl phosphite), the copper nanoparticles can improve the P.sub.B and P.sub.D of the lubricant to the greatest extent.

Example 4

(17) A lubricant comprises: 80 parts of a base oil; 2 parts of a methyl-silicone oil; 1 part of polymethacrylate; 4 parts of pentaerythritol polyisobutylene succinate; 2 parts of di-n-butyl phosphite; 3 parts of butylhydroxytoluene; 4 parts of an ethylene-propylene copolymer; 1 part of alkenyl succinate; and 3 parts of copper nanoparticles. The base oil comprises 70 wt. % of a synthetic oil and 30 wt. % of a trimethylolpropane ester, and the synthetic oil is a polyalphaolefin 6 (PAO6).

(18) A method of preparing the lubricant comprises: adding the base oil, the methyl-silicone oil, the polymethacrylate, the ethylene-propylene copolymer, the butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure (NTP) at 300 rpm for 4 hours, to yield a primary product; and adding the di-n-butyl phosphite, the pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 150 rpm for 2.5 hours.

Example 5

(19) A lubricant comprises: 82 parts of a base oil; 2 parts of a methyl-silicone oil; 1 part of polymethacrylate; 2 parts of pentaerythritol polyisobutylene succinate; 1 part of di-n-butyl phosphite; 3 parts of butylhydroxytoluene; 3 parts of an ethylene-propylene copolymer; 2 parts of alkenyl succinate; and 4 parts of copper nanoparticles. The base oil comprises 70 wt. % of a synthetic oil and 30 wt. % of a trimethylolpropane ester, and the synthetic oil is a polyalphaolefin 8 (PAO8).

(20) A method of preparing the lubricant comprises: adding the base oil, the methyl-silicone oil, the polymethacrylate, the ethylene-propylene copolymer, the butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure (NTP) at 400 rpm for 3 hours, to yield a primary product; and adding the di-n-butyl phosphite, the pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 250 rpm for 2 hours.

Example 6

(21) A lubricant comprises: 85 parts of a base oil; 1 part of a methyl-silicone oil; 1 part of polymethacrylate; 2 parts of pentaerythritol polyisobutylene succinate; 1 part of di-n-butyl phosphite; 2 parts of butylhydroxytoluene; 2 parts of an ethylene-propylene copolymer; 1 part of alkenyl succinate; and 5 parts of copper nanoparticles. The base oil comprises 70 wt. % of a synthetic oil and 30 wt. % of a trimethylolpropane ester, and the synthetic oil is a polyalphaolefin 10 (PAO10).

(22) A method of preparing the lubricant comprises: adding the base oil, the methyl-silicone oil, the polymethacrylate, the ethylene-propylene copolymer, the butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure (NTP) at 350 rpm for 4 hours, to yield a primary product; and adding the di-n-butyl phosphite, the pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 200 rpm for 2.5 hours.

(23) The properties of the lubricants prepared in above examples are tested and the test results are shown in FIGS. 1A-1B. The friction pairs employed in the tests comprise one of four types of carbon films (that is, pure carbon film, Si-doped carbon film, Al-doped carbon film, H-doped carbon film) and stainless-steel balls. Friction conditions: the stainless-steel balls have a diameter of 4 mm, a single stroke of 5 mm, a linear velocity of 10 mm/s and a vertical load of 8 N. The experiments are carried out at room temperature. As shown in FIGS. 1A and 1B, compared with the SL grade engine oil on the market, the lubricant as described in the disclosure can reduce the friction coefficient and wear rate of the four types of carbon films by 9-19% and 93-99%, respectively. It can be concluded that the lubricant of the disclosure can effectively protect the carbon film and exhibit efficient lubricating properties.

(24) It will be obvious to those skilled in the art that changes and modifications may be made, and therefore, the aim in the appended claims is to cover all such changes and modifications.