AQUEOUS GRAPHITE LUBRICANT COMPOSITIONS COMPRISING DISPERSANTS

Abstract

A lubricant composition includes water, graphite, a thickener and an alkylphenol ether sulfate dispersant.

Claims

1. A lubricant composition, comprising: water; graphite; a thickener; and an alkylphenol ether sulfate dispersant.

2. The lubricant composition of claim 1, wherein the lubricant composition comprises 20 wt % to 60 wt % water based on a total weight of the lubricant composition.

3. The lubricant composition of claim 1, wherein the lubricant composition comprises 10 wt % to 60 wt % of graphite based on a total weight of the lubricant composition.

4. The lubricant composition of claim 3, wherein the graphite has a D90 particle diameter of from 0.5 m to 5.0 m.

5. The lubricant composition of claim 1, wherein the thickener is a polysaccharide.

6. The lubricant composition of claim 1, wherein the lubricant composition comprises 0.01 wt % to 1.0 wt % of the dispersant based on a total weight of the lubricant composition.

7. The lubricant composition of claim 1, wherein dispersant has structure (I): ##STR00003## wherein the variable R is a C.sub.5-C.sub.20 alkyl, the variable x is an average value of 1.0 to 7.0, and the variable Z+ is selected from the group consisting of Li, K, NH.sub.4 and Na.

8. The lubricant composition of claim 7, wherein the variable Z+ of Structure (I) is NH.sub.4.

9. The lubricant composition of claim 8, wherein the variable x of Structure (I) has an average value of 4.2.

10. The lubricant composition of claim 8, wherein the variable R is a C.sub.9 alkyl.

Description

DETAILED DESCRIPTION

[0019] As used herein, the term and/or, when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

[0020] All ranges include endpoints unless otherwise stated.

[0021] As used herein, the term weight percent (wt %) designates the percentage by weight a component is of a total weight of the polymeric composition unless otherwise specified.

[0022] As used herein, Chemical Abstract Services registration numbers (CAS #) refer to the unique numeric identifier as most recently assigned as of the priority date of this document to a chemical compound by the Chemical Abstracts Service.

Lubricant Composition

[0023] The present disclosure is directed to a lubricant composition. The lubricant composition comprises water, graphite, a thickener, and an alkylated diphenyl oxide sulfonate dispersant. The lubricant composition may comprise 20 wt % to 60 wt % water based on a total weight of the lubricant composition. For example, the lubricant composition comprises 20 wt % or greater, or 25 wt % or greater, or 30 wt % or greater, or 35 wt % or greater, or 40 wt % or greater, or 45 wt % or greater, or 50 wt % or greater, or 55 wt % or greater, while at the same time, 60 wt % or less, or 55 wt % or less, or 50 wt % or less, or 45 wt % or less, or 40 wt % or less, or 35 wt % or less, or 30 wt % or less, or 25 wt % or less of water based on a total weight of the lubricant composition. The lubricant composition may comprise one or more other additives designed to alter a property of characteristic of the lubricant composition.

Thickener

[0024] The thickener is included in the lubricant composition to aid in the application and retention of the lubricant composition on surfaces. The thickener may comprise a polysaccharide such as agar, sodium alginate, rhamsam gum, locust bean gum, carrageenan, gum arabic, neem gum, gum chatti, caranna, galactomannan, gum tragacanth, karaya gum, guar gum, welan gum, beta-glucan, cellulose, chicle gum, kino gum, dammar gum, glucomannan, acacia gum, cassia gum, mastic gum, spruce gum, pysllium seed husks, gellan gum, xanthan gum, diutan gum, fenugreek gum, ghatti gum, methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, karaya gum, konjac gum, pectin and combinations thereof. Additionally or alternatively, the thickener may also include other viscosity modifying components such as polyethylene glycol, polyacrylic acid, polyethyleneimine, polyvinyl alcohol, polyacrylamides, carboxyvinyl polymers, poly(vinylpyrrolidinone) and copolymers, polyoxypropylene and combinations thereof.

[0025] The lubricant composition may comprise 0.1 wt % to 5.0 wt % thickener based on a total weight of the lubricant composition. For example, the lubricant composition may comprises 0.1 wt % or greater, or 0.2 wt % or greater, or 0.4 wt % or greater, or 0.6 wt % or greater, or 0.8 wt % or greater, or 1.0 wt % or greater, or 1.5 wt % or greater, or 2.0 wt % or greater, or 2.5 wt % or greater, or 3.0 wt % or greater, or 3.5 wt % or greater, or 4.0 wt % or greater, or 4.5 wt % or greater, while at the same time, 5.0 wt % or less, or 4.5 wt % or less, or 4.0 wt % or less, or 3.5 wt % or less, or 3.0 wt % or less, or 2.5 wt % or less, or 2.0 wt % or less, or 1.5 wt % or less, or 1.0 wt % or less, or 0.5 wt % or less of the thickener based on the total weight of the lubricant composition.

Graphite

[0026] The lubricant composition comprises graphite. The graphite may have spherical shape, a plate like shape, an oblong shape and/or an irregular shape. The particles of the graphite may have a D90 of from 0.5 microns (m) to 10 m. As used herein, the term D90 means that 90% of the graphite particles have a diameter or longest length dimension smaller than the indicated value and 10% of the particles have a diameter or longest length dimension greater than the indicated value. The graphite may have a D90 particle size of 0.5 m or greater, or 1.0 m or greater, or 1.5 m or greater, or 2.0 m or greater, or 2.5 m or greater, or 3.0 m or greater, or 3.5 m or greater, or 4.0 m or greater, or 4.5 m or greater, or 5.0 m or greater, or 5.5 m or greater, or 6.0 m or greater, or 6.5 m or greater, or 7.0 m or greater, or 7.5 m or greater, or 8.0 m or greater, or 8.5 m or greater, or 9.0 m or greater, or 9.5 m or greater, while at the same time, 10 m or less, or 9.5 m or less, or 9.0 m or less, or 8.5 m or less, or 8.0 m or less, or 7.5 m or less, or 7.0 m or less, or 6.5 m or less, or 6.0 m or less, or 5.5 m or less, or 5.0 m or less, or 4.5 m or less, or 4.0 m or less, or 3.5 m or less, or 3.0 m or less, or 2.5 m or less, or 2.0 m or less, or 1.5 m or less, or 1.0 m or less. The D90 particle size of the graphite is determined using a Malvern Mastersizer laser diffraction particle size analyzer.

[0027] The lubricant composition comprises 10 wt % to 60 wt % of graphite based on a total weight of the lubricant composition. For example, the lubricant composition comprises 10 wt % or greater, or 15 wt % or greater, or 20 wt % or greater, or 25 wt % or greater, or 30 wt % or greater, or 35 wt % or greater, or 40 wt % or greater, or 45 wt % or greater, or 50 wt % or greater, or 55 wt % or greater, while at the same time, 60 wt % or less, or 55 wt % or less, or 50 wt % or less, or 45 wt % or less, or 40 wt % or less, or 35 wt % or less, or 30 wt % or less, or 25 wt % or less, or 20 wt % or less, or 15 wt % or less of graphite based on a total weight of the lubricant composition.

Dispersant

[0028] The lubricant composition comprises a dispersant that is an alkylphenol ether sulfate dispersant. The dispersant may have Structure (I):

##STR00001## [0029] wherein the variable R of structure (I) is a C.sub.5-C.sub.20 alkyl, the variable x is an average value of 1.0 to 7.0, and Z+ is selected from the group consisting of Li, K, NH.sub.4 and Na. R may be a C.sub.5 alkyl, or a C.sub.6 alkyl, or a C.sub.7 alkyl, or a C.sub.8 alkyl, or a C.sub.9 alkyl, or a C.sub.10 alkyl, or a C.sub.11 alkyl, or a C.sub.12 alkyl, or a C.sub.13 alkyl, or a C.sub.14 alkyl, or a C.sub.15 alkyl, or a C.sub.16 alkyl, or a C.sub.17 alkyl, or a C.sub.18 alkyl, or a C.sub.19 alkyl, or a C.sub.20 alkyl. R may be a linear or a branched alkyl. R may include one or more carbons that are secondary or tertiary.

[0030] The variable x of Structure (I) describes the average molar units of oxyethylene in Structure (I). As defined herein, the x value is tested and determined by Proton Nuclear Magnetic Resonance Spectroscopy and Carbon-13 Nuclear Magnetic Resonance Spectroscopy. x may be a value of 1.0 or greater, or 1.2 or greater, or 1.4 or greater, or 1.6 or greater, or 1.8 or greater, or 2.0 or greater, or 2.2 or greater, or 2.4 or greater, or 2.6 or greater, or 2.8 or greater, or 3.0 or greater, or 3.2 or greater, or 3.4 or greater, or 3.6 or greater, or 3.8 or greater, or 4.0 or greater, or 4.2 or greater, or 4.4 or greater, or 4.6 or greater, or 4.8 or greater, or 5.0 or greater, or 5.2 or greater, or 5.4 or greater, or 5.6 or greater, or 5.8 or greater, or 6.0 or greater, or 6.2 or greater, or 6.4 or greater, or 6.6 or greater, or 6.8 or greater, while at the same time, 7.0 or less, or 6.8 or less, or 6.6 or less, or 6.4 or less, or 6.2 or less, or 6.0 or less, or 5.8 or less, or 5.6 or less, or 5.4 or less, or 5.2 or less, or 5.0 or less, or 4.8 or less, or 4.6 or less, or 4.4 or less, or 4.2 or less, or 4.0 or less, or 3.8 or less, or 3.6 or less, or 3.4 or less, or 3.2 or less, or 3.0 or less, or 2.8 or less, or 2.6 or less, or 2.4 or less, or 2.2 or less, or 2.0 or less, or 1.8 or less, or 1.6 or less, or 1.4 or less, or 1.2 or less.

[0031] The lubricant composition may comprise 0.1 wt % to 5.0 wt % dispersant based on a total weight of the lubricant composition. For example, the lubricant composition comprises 0.1 wt % or greater, or 0.2 wt % or greater, or 0.3 wt % or greater, or 0.4 wt % or greater, or 0.5 wt % or greater, or 0.6 wt % or greater, or 0.7 wt % or greater, or 0.8 wt % or greater, or 0.9 wt % or greater, or 1.0 wt % or greater, or 1.5 wt % or greater, or 2.0 wt % or greater, or 2.5 wt % or greater, or 3.0 wt % or greater, or 3.5 wt % or greater, or 4.0 wt % or greater, or 4.5 wt % or greater, while at the same time, 5.0 wt % or less, or 4.5 wt % or less, or 4.0 wt % or less, or 3.5 wt % or less, or 3.0 wt % or less, or 2.5 wt % or less, or 2.0 wt % or less, or 1.5 wt % or less, or 1.0 wt % or less, or 0.9 wt % or less, or 0.8 wt % or less, or 0.7 wt % or less, or 0.6 wt % or less, or 0.5 wt % or less, or 0.4 wt % or less, or 0.3 wt % or less, or 0.2 wt % or less of the dispersant based on the total weight of the lubricant composition.

EXAMPLES

Materials

[0032] The following materials were used in the examples.

[0033] Graphite is a powder of graphite particles having a D90 of 5.0 m and is commercially available from Molygraph Lubricants, Mumbai, India.

[0034] Thickener is xanthan gum commercially available from Loba Chemie Mumbai, India.

[0035] Dispersant 1 is a solution of an alkylammonium salt of a polycarboxylic acid sold under the tradename ANTI-TERRA and is commercially available from BYK-Chemie GmbH, Wesel, Germany.

[0036] Dispersant 2 is a 97 wt % actives powder having Structure (II), a CAS # of 9084-06-4 and is available from The Dow Chemical Company, Midland Michigan.

##STR00002##

[0037] Dispersant 3 is pure sodium dodecyl sulfate having a CAS # of 151-21-3 and is available from commercially available from Loba Chemie Mumbai, India.

[0038] Dispersant 4 is an acrylic acid homopolymer that is end capped with poly(phthalaldehyde), has a weight average molecular weight of 2000 g/mol, has a 47-49 wt % solids content and is available from The Dow Chemical Company, Midland Michigan.

[0039] Dispersant 5 is an aqueous solution of water, Structure (I) and (2-hydroxyethyl) ammonium nonylphenol ethoxylate sulfate. Dispersant 5 comprises 30 wt % to 54 wt % of Structure (I), 6 wt % to 30 wt % of the (2-hydroxyethyl) ammonium nonylphenol ethoxylate sulfate and 6 wt % to 24 wt % of water. Structure (I) of Dispersant 5 is as follows: the variable R is a C.sub.9 alkyl having a tertiary terminal carbon atom, the variable x has an average value of 4.2 and the variable Z+ is NH.sub.4. Dispersant 5 is available from The Dow Chemical Company, Midland Michigan.

[0040] Water is distilled water.

Sample Preparation

[0041] The examples were prepared by first combining the thickener, the dispersant, a portion of the water and then mixing the solution for 1 minute using a stirrer. Next, the graphite powder was added slowly to the solution and mixed until a paste was formed. Next, the graphite paste was diluted with the remaining water and mixed using an overhead stirrer to form a dispersion having the composition listed in the Table 1. The diluted paste was then added to a 100 milliliter (ml) volumetric flask and filled to the 100 ml line.

Test Method

[0042] Sedimentation Test: The Sedimentation Test determines what percentage of the dispersion remains dispersed after a predetermined period of time. The 100 ml volumetric flask is filled to the 100 ml mark with the example and the flask is left undisturbed for the indicated period of time. The amount of example remaining dispersed is measured by visually observing the phase separation interface between a clear or hazy water phase and a dispersed graphite phase. The phase separation is determined by examining at what ml demarcation the graphite dispersion phase and water phase is at after an identified period of time, dividing by the initial 100 ml and multiplying by 100. For example, if the interface of the graphite dispersion phase and the water phase is at 95 ml, then 95% of the dispersion resisted phase separation. An example is considered to have passed the Sedimentation Test if 90% of the example remains in the graphite dispersion phase after 720 hours (i.e., 30 days).

Results

[0043] Table 1 below provides the composition of each comparative example (CE) and each inventive example (IE) in weight percents of components while Table 2 provides the performance data of each IE and CE. The data of Table 2 provides the percent of the example remaining in the graphite dispersion phase. The entry nm indicates that a particular time interval was not measured.

TABLE-US-00001 TABLE 1 Component CE1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 CE9 CE10 IE1 IF2 Graphite 30 50 30 50 30 50 30 50 30 50 30 50 Thickener 1 1 1 1 1 1 1 1 1 1 1 1 Dispersant 0.5 2.0 1 Dispersant 0.5 2.0 2 Dispersant 0.5 2.0 3 Dispersant 0.5 2.0 4 Dispersant 0.5 2.0 5 Water 69 49 68.5 47 68.5 47 68.5 47 68.5 47 68.5 47

TABLE-US-00002 TABLE 2 Time (hrs) CE1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 CE9 CE10 IE1 IE2 0 90 95 90 95 90 95 90 95 90 95 90 95 0.16 50 65 90 50 87 90 87 90 90 90 90 95 2 29 nm 87 nm 85 nm 80 nm 87 nm 90 nm 48 30 35 70 33 15 50 18 40 50 50 90 95 72 28 33 50 32 10 35 15 30 20 40 90 95 720 21 32 5 30 3 25 10 20 5 30 90 95

[0044] As can be seen from Tables 1 and 2, IE1 and IE2 drastically outperform CE1-CE10 in terms of producing a lubricant composition that passes the Sedimentation Test as indicated IE1 and IE2 all maintaining 90% graphite dispersion after 720 hours. CE1 and CE2 demonstrate a baseline for the stability that can be expected from an aqueous graphite dispersion when no dispersants are included. CE3 though CE10 demonstrate that the inclusion of certain dispersants can actually decrease the stability of graphite in water relative to dispersions having no dispersant as evidenced by lower percentages of retained graphite dispersion phases of CE3-CE10 relative to CE1 and CE2.

[0045] Unlike CE1-CE10, each of IE1 and IE2 is able to maintain 90% or greater of the graphite dispersion phase after 30 days of testing and therefore pass the Sedimentation Test. Such a result is surprising because every comparative example utilizing a dispersant demonstrated worse performance than CE1 and CE2 which did not include a dispersant. As explained above, it is believed that the spacing between the phenyl and sulfate moieties of the dispersant provided by the ether bridge of the dispersants used in IE1 and IE2 increase the dispersant's ability to interact/bond with the surface of the graphite is enhanced relative to other dispersants.