Gelling agent for calcium sulfonate lubricating grease

Abstract

A calcium sulfonate grease formed from a base oil of lubricating viscosity, an oil-soluble overbased calcium sulfonate or a precursor thereof, a conversion acid, water, and a gelling agent selected from branched aliphatic glycols having at least eight carbons and mixtures thereof.

Description

Technical Field

[0001] The present invention relates generally to lubricating greases and finds particular application in conjunction with calcium sulfonate greases prepared using a gelling agent comprising at least one aliphatic C8 or higher diol such as 2-ethyl-1,3-hexanediol, and to methods of preparing the greases and to methods of lubrication. Background Art

[0002] Gelled calcium sulfonate greases are typically prepared by mixing an overbased calcium sulfonate detergent with a base oil. The mixture is treated with an acid to destabilize the micellar structure, followed by the addition of a gelling agent and water. Over a period of several hours, at a suitable gelling temperature, the amorphous calcium carbonate in the mixture is converted to crystalline calcite and forms a viscous grease.

[0003] The gelling agent is typically a hydroxyl source, such as an alcohol or glycol, which promotes the conversion of the overbased detergent amorphous calcium carbonate to a calcium sulfonate grease with calcite.

[0004] This method is more fully described in the following references:

[0005] U.S. Pat. No. 3,242,079 issued to McMillen, entitled BASIC METAL-CONTAINING THICKENED OIL COMPOSITIONS, describes a homogeneous grease composition prepared by mixing a fluid mineral oil solution containing a sulfonate or carboxylate and an active hydrogen compound selected from lower aliphatic carboxylic acids, water and water-alcohol mixtures.

[0006] U.S. Pat. No. 3,714,042, entitled TREATED OVERBASED COMPLEXES, issued to Greenough on Jan. 30, 1973, describes treating overbased complexes with high molecular weight aliphatic carboxylic acids, anhydrides, esters, amides, imides or salts. The treated overbased complexes are useful as additives in lubricating oils, gasoline and other organic materials.

[0007] U.S. Patent No. 5,126,062 to Barnes, entitled CALCIUM SULFONATE GREASE AND METHOD OF MANUFACTURE, issued on June 30, 1992, describes an overbased calcium sulfonate complex grease comprising neutral oil, calcium sulfonate, calcium carbonate, dodecylbenzyl sulfonic acid, isopropyl alcohol, water, calcium hydroxide, 12-hydroxystearic acid, phosphoric acid and an antioxidant.

[0008] U.S. Pat. No. 5,308,514, entitled SULFONATEGREASES, issued to Olson et al. on May 3, 1994, and U.S. Pat. No. 5,338,467, entitled SULFONATE GREASE IMPROVEMENT, issued to Olson et al. on August 16, 1994, describe greases comprising solid particles of overbased calcium sulfonate and colloidally dispersed calcium carbonate in the form of calcite, the grease being formed by heating overbased calcium sulfonate, amorphous calcium carbonate, and a fatty acid having twelve to twenty-four carbon atoms in oil.

[0009] One problem with existing gelling agents is that the conversion process of amorphous calcium carbonate to crystalline calcite is generally slow. In addition, since the gelling agent is generally removed by vaporization at the end of the gelling process, it is desirable that it has low toxicity in the event of release into the environment.

[0010] There remains a need to provide a gelling agent that is fast converting while being safe in use. Summary of the invention

[0011] According to one aspect of the exemplary embodiment, the calcium sulfonate grease is formed from a base oil of lubricating viscosity, an oil-soluble overbased calcium sulfonate or a precursor thereof, a conversion acid and a gelling agent selected from branched aliphatic diols having at least eight carbon atoms and mixtures thereof.

[0012] In calcium sulfonate greases, the gelling agent may be selected from branched aliphatic diols having eight to ten carbons.

[0013] The gelling agent may be selected from a branched aliphatic diol having eight carbons, a branched aliphatic diol having nine carbons, and mixtures thereof, such as a branched aliphatic diol having eight carbons.

[0014] The gelling agent may include at least one of 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-propylene glycol, and 2,5-dimethyl-2,5-hexanediol.

[0015] The gelling agent may be at least 0.5 wt %, or at least 1 wt %, or up to 5 wt %, or up to 3 wt % of the total weight of the base oil, oil-soluble overbased calcium sulfonate or precursor thereof, conversion acid and gelling agent.

[0016] The gelling agent may include or consist essentially of 2-ethyl-1,3-hexanediol.

[0017] 2-Ethyl-1,3-hexanediol may be at least 0.5 wt % or at least 1 wt % of the total weight of the base oil, oil-soluble overbased calcium sulfonate or precursor thereof, conversion acid and gelling agent.

[0018] The conversion acid can be selected from alkylbenzenesulfonic acid having an aliphatic chain of 8 to 36 carbon atoms, succinic acid having an aliphatic chain of 8 to 36 carbon atoms, succinic acid having an alkyl or alkenyl group at C2 or C3 of succinic acid and having an aliphatic chain of 8 to 36 carbon atoms, and mixtures thereof.

[0019] The conversion acid may be at least 1 wt %, or at least 3 wt %, or at least 4 wt %, or up to 15 wt %, or up to 12 wt % of the total weight of the base oil, oil-soluble overbased calcium sulfonate or precursor thereof, conversion acid and gelling agent.

[0020] The oil-soluble overbased calcium sulfonate may have a total base number (TBN) of at least 300 mg KOH / g eq, or at least 350 mg KOH / g eq, or at most 600 mg KOH / g eq, or at most 500 mg KOH / g eq as measured according to ASTM D2896.

[0021] The oil-soluble overbased calcium sulfonate may be a calcium salt of a sulfonic acid selected from the group consisting of alkyl sulfonic acids, aryl sulfonic acids, alkyl aryl sulfonic acids, and mixtures thereof.

[0022] The oil-soluble overbased calcium sulfonate may comprise or consist of a calcium salt of a sulfonic acid having at least 10, or at least 12, or at least 20 aliphatic carbon atoms, or up to 36, or up to 30, or up to 24 aliphatic carbon atoms.

[0023] The oil-soluble overbased calcium sulfonate may comprise a calcium salt of a sulfonic acid selected from the group consisting of dodecylbenzenesulfonic acid, didodecylbenzenesulfonic acid, dinonylbenzenesulfonic acid, dinonyl substituted naphthalenesulfonic acid, petroleum sulfonic acid, mono-wax (eicosane) substituted naphthalenesulfonic acid, octadecyldiphenyl ether sulfonic acid, octadecyldiphenylamine sulfonic acid, hexadecylchlorobenzenesulfonic acid, dilauryl β-naphthalenesulfonic acid, sulfonic acid derived by treating polyisobutylene with chlorosulfonic acid, nitronaphthalenesulfonic acid, paraffin sulfonic acid, hexadecylcyclopentanesulfonic acid, laurylcyclohexanesulfonic acid, polyethylenesulfonic acid, and mixtures thereof.

[0024] The oil-soluble overbased calcium sulfonate may comprise or consist of a synthetic calcium salt of an alkylbenzene sulfonic acid comprising at least one C8-C36 alkyl group or at least one C8-C24 alkyl group.

[0025] The oil-soluble overbased calcium sulfonate may comprise calcium carbonate.

[0026] The oil-soluble overbased calcium sulfonate may be at least 3 wt%, or at least 5 wt%, or at least 8 wt%, or up to 25 wt%, or up to 20 wt%, or up to 15 wt%, of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or precursor thereof, the conversion acid, and the gelling agent.

[0027] The base oil may be at least 40 wt %, or at least 50 wt %, or at least 60 wt %, or up to 90 wt %, or up to 80 wt % of the total weight of the base oil, oil-soluble overbased calcium sulfonate or precursor thereof, conversion acid and gelling agent.

[0028] Calcium sulfonate greases can further be formed from water.

[0029] Water may be added in an amount of 2 to 25 parts by weight or up to 15 parts by weight based on the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent.

[0030] The calcium sulfonate grease may be a calcium sulfonate complex grease further prepared with at least one of a complexing agent and a saponifying agent.

[0031] The complexing agent may be selected from long chain carboxylic acids or their calcium salts, short chain carboxylic acids or their calcium salts, boric acid, its salts and organic boron compounds, phosphoric acid, sulfonic acid and mixtures thereof.

[0032] The complexing agent may comprise at least 0.5 wt%, or at least 1 wt%, or at least 2 wt%, or at most 12 wt%, or at most 10 wt%, based on the total weight of the complex grease.

[0033] The saponifying agent may be selected from calcium oxide, calcium hydroxide, calcium carbonate and mixtures thereof.

[0034] The saponifier may comprise at least 0.5 wt%, or at least 1 wt%, or at least 2 wt%, or at most 10 wt%, or at most 6 wt%, of the total weight of the complex grease.

[0035] The calcium sulfonate grease may further comprise at least one performance additive selected from antioxidants, antiwear agents, extreme pressure agents, friction modifiers, viscosity modifiers, metal deactivators and / or corrosion inhibitors and mixtures thereof.

[0036] The at least one performance additive may total at least 0.01 wt %, or at least 0.1 wt %, or up to 10 wt %, or up to 5 wt %, or up to 3 wt % of the calcium sulfonate grease.

[0037] According to another aspect of the exemplary embodiment, a method of forming a calcium sulfonate grease includes combining a base oil of lubricating viscosity, an oil-soluble overbased calcium sulfonate or a precursor thereof, a conversion acid, a gelling agent, and water to form a mixture, wherein the gelling agent is selected from a branched aliphatic diol having at least eight carbons and mixtures thereof; and heating the mixture to a gelling temperature at which the mixture forms a gel.

[0038] In this method, the mixture may be an emulsion and may be formed at a temperature below 30°C.

[0039] The method may further include incorporating at least one of a complexing agent and a saponifying agent into the gel to form a calcium sulfonate complex grease.

[0040] According to another aspect of the exemplary embodiment, a formulation for forming a calcium sulfonate grease comprises 3 wt % to 20 wt % overbased calcium sulfonate; 1 wt % to 12 wt % conversion acid; 0.5 wt % to 6 wt % gelling agent; 2 wt % to 25 wt % water; and at least 30 wt % base oil. DETAILED DESCRIPTION

[0041] Aspects of the exemplary embodiments are directed to a calcium sulfonate grease prepared using a gelling agent including at least one branched aliphatic diol having at least eight carbons.

[0042] In one embodiment, the gelling agent comprises or consists of 2-ethyl-1,3-hexanediol.

[0043] Calcium sulfonate greases can be prepared from the following materials: (1) a base oil of lubricating viscosity, (2) an oil-soluble overbased calcium sulfonate, or a precursor for forming an overbased calcium sulfonate, such as a source of calcium sulfonate and calcium carbonate, (3) a conversion acid, (4) a gelling agent, and (5) water.

[0044] Additional components may be used to form the calcium sulfonate grease. To prepare a calcium sulfonate complex grease, rather than a simple calcium sulfonate grease, components (1) to (5) plus (6) a complexing agent and optionally (7) a saponifying agent may be employed. One or more performance additives may be incorporated into the calcium sulfonate grease.

[0045] A method of making a simple calcium sulfonate grease may include mixing the prepared overbased calcium sulfonate with a base oil and a conversion acid to destabilize the micellar structure of the calcium carbonate in the overbased calcium sulfonate. An exemplary gelling agent and water are added, and the resulting emulsion is heated to its gelling temperature. The amorphous calcium carbonate is converted to crystalline calcite, typically within 1 hour. Removing the water and gelling agent from the mixture produces a gelled calcium sulfonate grease. Performance additives may be incorporated into the grease. Other methods of making simple calcium sulfonate greases using the exemplary gelling agents are also contemplated.

[0046] A method of preparing a calcium sulfonate complex grease may include combining a base oil with a calcium sulfonate overbased with calcium carbonate, an acid, a gelling agent, and water, as described for a simple calcium sulfonate grease, followed by the addition of a complexing acid and optionally a calcium source. Performance additives may be incorporated into the grease. Some advantages of calcium sulfonate complex greases over simple greases include reduced tack, improved pumpability, and improved high temperature utility.

[0047] A method of lubricating a mechanical device may include applying a calcium sulfonate simple grease or a calcium sulfonate complex grease to the mechanical device.

[0048] 1. Base oil with lubricating viscosity

[0049] The grease may comprise a base oil as a minor or major component, such as at least 5 wt %, or at least 10 wt %, or at least 20 wt %, or at least 30 wt %, or at least 40 wt %, or at least 60 wt %, or at least 80 wt %, or up to 94 wt % of the grease.

[0050] When forming a grease, the base oil may be at least 30 wt %, or at least 40 wt %, or at least 50 wt %, or at least 60 wt %, or up to 95 wt %, or up to 90 wt %, or up to 80 wt % of the combined weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent (i.e., components (1) to (4)).

[0051] Such base oils include natural oils and synthetic oils, derived from hydrocracking, hydrogenation and hydrofining oils, unrefined oils, refined oils, re-refined oils or mixtures thereof. Unrefined oils, refined oils and re-refined oils as well as natural oils and synthetic oils are described in, for example, WO2008 / 147704 and U.S. Publication No. 2010 / 197536. Synthetic oils can also be produced by Fischer-Tropsch reaction, and can generally be Fischer-Tropsch hydrocarbons or waxes of hydroisomerization. Oil can be prepared by Fischer-Tropsch gas-to-liquid synthesis procedures and other gas-to-liquid procedures.

[0052] Oils of lubricating viscosity may also be defined in accordance with the provisions of "Appendix E - API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils", April 2008 edition, Section 1.3, Subheading 1.3, "Base Stock Categories". The API guidelines are also summarized in U.S. Pat. No. 7,285,516. The five classes of base oils are as follows: Class I (sulfur content > 0.03 wt %, and / or < 90 wt % saturates, viscosity index 80-120); Class II (sulfur content < 0.03 wt %, and > 90 wt % saturates, viscosity index 80-120); Class III (sulfur content < 0.03 wt %, and > 90 wt % saturates, viscosity index > 120); Class IV (all polyalphaolefins (PAOs)); Class V (all other oils not included in Class I, II, III or IV). Exemplary oils with lubricating viscosity include API Class I, Class II, Class III, Class IV, Class V oils or mixtures thereof. In some embodiments, the oil with lubricating viscosity is API Class I, Class II, Class III or Class IV oils or mixtures thereof. In some embodiments, the oil with lubricating viscosity is API Class I, Class II or Class III oils or mixtures thereof. In one embodiment, the oil with lubricating viscosity can be API Class II, Class III mineral oils, Class IV synthetic oils or mixtures thereof.

[0053] The kinematic viscosity (KV40) of the base oil may be 100 cSt to 650 cSt, such as about 110 cSt or about 500 cSt. The viscosity (KV40) is measured at 40°C according to ASTM D445-21 e 1 "Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)". The viscosity (KV100) is the kinematic viscosity measured at 100°C according to ASTM D445.

[0054] In one embodiment, the base oil for forming the grease includes one or more mineral oils. Example mineral oils useful herein include API Class I base oils, Class II paraffinic mineral oils, and mixtures thereof. An example Class I base oil is named 150 Brightstock (150BS), which has a viscosity (KV40) of 461 cSt to 597 cSt. Another suitable base oil is Americas CORE available from ExxonMobil Corporation. TM2500, which has a KV100 of 30.6 cSt to 32.7 cSt. However, other natural and synthetic base oils are also contemplated.

[0055] 2. Oil-soluble calcium sulfonate

[0056] Calcium sulfonate is a salt of calcium and a long chain sulfonic acid. The calcium sulfonate may have a molecular weight of at least 400. The calcium sulfonate may be overbased. "Overbased" means that the calcium is in excess of a stoichiometric amount relative to the sulfonate counterion. Overbased calcium sulfonate may have a metal:sulfonate ratio of at least 3:1, or at least 4:1, or at least 6:1.

[0057] Suitable overbased calcium sulfonates can have a total base number (TBN) of at least 300 mg KOH / g eq, or at least 350 mg KOH / g eq, or at most 600 mg KOH / g eq, or at most 500 mg KOH / g eq. As used herein, TBN is measured according to ASTM D2896-21 "Standard Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid Titration".

[0058] Example sulfonic acids for forming calcium sulfonate include alkyl (including cycloalkyl), aryl and alkylaryl sulfonic acids, wherein the aryl group can be benzene, toluene, naphthalene, etc. The sulfonic acid can contain at least 10, or at least 12, or at least 20 aliphatic carbon atoms in the molecule, and / or contain up to 36, or up to 30, or up to 24 aliphatic carbon atoms in the molecule (e.g., in one or two alkyl chains and / or cycloalkyl). Examples include petroleum sulfonic acids or acids obtained by treating alkylated aromatic hydrocarbons with a sulfonating agent (e.g., chlorosulfonic acid, sulfur trioxide, oleum, sulfuric acid or sulfur dioxide and chlorine). Sulfonic acids obtained by sulfonating alkylated benzene, alkylated naphthalene, alkylated toluene, alkylated phenol, alkylated phenol sulfide or alkylated diphenyl ether are particularly useful.

[0059] In one embodiment, the sulfonic acid is a synthetic sulfonic acid which allows the alkyl chain length to be controlled to a reasonable degree. In another embodiment, the sulfonic acid is derived from a petroleum distillate which can have a wider range of alkyl chain lengths.

[0060] Specific examples of the sulfonic acid include dodecylbenzenesulfonic acid, didodecylbenzenesulfonic acid, dinonylbenzenesulfonic acid, dinonyl-substituted naphthalenesulfonic acid, petroleum sulfonic acid (a mixture of sulfonic acid derivatives of petroleum obtained as a by-product in refining white oil with sulfuric acid or made as a main product by sulfonation of petroleum distillates), monowax (eicosane)-substituted naphthalenesulfonic acid, octadecyldiphenyl ethersulfonic acid, octadecyldiphenylaminesulfonic acid, hexadecylchlorobenzenesulfonic acid, dilauryl β-naphthalenesulfonic acid, sulfonic acid derived from polyisobutylene having a molecular weight of about 1500 by treating it with chlorosulfonic acid, nitronaphthalenesulfonic acid, paraffinsulfonic acid, hexadecylcyclopentanesulfonic acid, laurylcyclohexanesulfonic acid, polyethylenesulfonic acid, and mixtures thereof.

[0061] In one embodiment, the sulfonate is a synthetic calcium salt of an alkylbenzene sulfonic acid comprising at least one C8-C 36 Alkyl groups. Linear alkylbenzenes may have benzene rings attached anywhere on the linear chain (typically at the 2, 3 or 4 positions) or mixtures thereof. Alkylbenzene sulfonates may be branched alkylbenzene sulfonates, linear alkylbenzene sulfonates or mixtures thereof. Non-limiting examples include dodecylbenzene sulfonic acid, didodecylbenzene sulfonic acid, dinonylbenzene sulfonic acid and mixtures thereof.

[0062] In another specific embodiment, the sulfonate is a petroleum-derived petroleum sulfonate or a green sulfonate as described in US Pat. No. 3,242,079.

[0063] The calcium sulfonate may be overbased with calcium carbonate by combining the calcium sulfonate with calcium carbonate or a precursor thereof in an amount sufficient to provide an overbased calcium sulfonate having a total base number (TBN) of at least 300, or at least 350, or up to 600, or up to 500, such as about 400 (on an oil-free basis).

[0064] Commercially available overbased calcium sulfonate detergents of this type include the following: HiTEC 611 from Afton Chemical TM, Hybase C401 from Chemtura USA Corporation, Syncal OB 400 and Syncal OB405-WO from Kimes Technologies International Corporation, and Lubrizol 5358 (a 400 TBN detergent) from Lubrizol. Other examples of 400 TBN overbased calcium sulfonate detergents include 75GR, 75NS, 75P, 75WO, 5347 and 5347LC products from Lubrizol, CSQL-400S, QLS 207 and QLS207WO products from Quimico Liposolubles SA de CV, MX3240 SN500 and MX3240WO from ENI. Examples of 300 TBN overbased calcium sulfonate detergents include products 5342 and 6478A from The Lubrizol Corporation and QLS206 from Quimco Variable Capital Ltd. Typically, these commercial products are mixtures of calcium sulfonate, calcium carbonate, and lime in a suitable oil.

[0065] In one embodiment, to form the overbased calcium sulfonate, calcium oxide and / or calcium hydroxide are combined with the calcium sulfonate and optionally an oil (which may be the same as the base oil). Carbon dioxide is bubbled through the reaction mixture, thereby incorporating excess calcium carbonate into the calcium sulfonate, which imparts reserve alkalinity to the overbased calcium sulfonate.

[0066] The calcium carbonate in the overbased calcium sulfonate detergent may have a maximum particle size of less than 20 microns and a quartz content of less than about 0.05% by weight.

[0067] When forming a grease, the oil-soluble overbased calcium sulfonate may be at least 3 wt%, or at least 5 wt%, or at least 8 wt%, or at most 25 wt%, or at most 20 wt%, or at most 15 wt%, of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent (i.e., components (1) to (4)).

[0068] In one embodiment, the overbased calcium sulfonate (or precursor) may be at least 2 wt%, or at least 4 wt%, or up to 15 wt%, or up to 8 wt%, of the total weight of all components used to form the grease.

[0069] 3. Conversion acid

[0070] The conversion acid used to convert calcium carbonate into calcite can be selected from alkylbenzenesulfonic acids with an aliphatic chain of 8 to 36 carbon atoms, succinic acid with an aliphatic chain of 8 to 36 carbon atoms, succinic acid with an alkyl or alkenyl group at C2 or C3 of succinic acid and an aliphatic chain of 8 to 36 carbon atoms, succinic acid, benzoic acid and mixtures thereof.

[0071] The conversion acid, measured on an oil-free basis, may be at least 0.5% by weight of the total weight of the components used to form the grease (including components (1) to (5) and optionally components (6) and (7) where the grease is a composite grease). When forming the grease, the conversion acid may be at least 1% by weight, or at least 3% by weight, or at least 4% by weight, or at most 15% by weight, or at most 12% by weight of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent (i.e., components (1) to (4)).

[0072] The amount of converting acid used in the grease formulation may depend in part on the strength of the acid and the amount of slaked lime in the formulation.

[0073] 4. Gelling agent

[0074] In addition to any water present, the gelling agent also serves as a source of OH groups. The gelling agent facilitates the conversion of amorphous calcium carbonate to very finely divided crystalline calcium carbonate. The gelling agent includes a branched aliphatic diol with at least eight carbons, such as a C8-C10 diol or a C8-C9 diol or a mixture thereof, particularly a C8 diol. Particularly suitable diols are those diols that can convert at least 90% by weight, or at least 95% by weight, or at least 98% by weight of amorphous calcium carbonate present in the grease formulation into calcite at a gelling temperature (e.g., in the range of 89° C. to 94° C.) within 1 hour (such as within 45 minutes or less) when the gelling agent is added, particularly when used with a strong conversion acid (such as a straight or branched alkylbenzene sulfonic acid with an aliphatic chain of 8 to 36 carbon atoms).

[0075] In one embodiment, the branched aliphatic diol does not include an ether group. In one embodiment, the branched aliphatic diol consists only of the elements carbon, hydrogen and oxygen. In one embodiment, the diol includes only two OH groups. The two OH groups may be separated by a chain of up to three carbon atoms.

[0076] In one embodiment, the gelling agent comprises or consists of at least one diol selected from 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol and 2-butyl-2-ethyl-propylene glycol or a combination thereof. In one embodiment, the weight ratio of 2-ethyl-1,3-hexanediol to the sum of all other diols used as the gelling agent can be at least 1:1, or at least 2:1, or at least 3:1, or at least 5:1, or at least 10:1. The gelling agent can consist of or consist essentially of 2-ethyl-1,3-hexanediol (at least 95% by weight or at least 98% by weight of the gelling aid is 2-ethyl-1,3-hexanediol).

[0077] The gelling agent may be at least 0.5% by weight of the total weight of the components used to form the grease (including components (1) to (5) and optionally components (6) and (7) when the grease is a composite grease). When forming the grease, the gelling agent may be at least 0.5% by weight, or at least 1% by weight, or at most 5% by weight, or at most 3% by weight of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent (i.e., components (1) to (4)).

[0078] 5. Water

[0079] The water is present in an amount sufficient to allow the conversion to occur. This may depend in part on the type of reactor used to form the grease. In a substantially closed reactor, evaporated water from the reaction condenses on the surface of the reactor and returns to the reaction. In contrast, in an open reactor, more water may be required to make up for evaporated water that is not recaptured.

[0080] Water may be present in an amount of 3 wt% or more of the total weight of the components used to form the grease (including components (1) to (5) and optionally components (6) and (7) in the case where the grease is a composite grease). In one embodiment, water may be added in an amount of 2 to 25 parts by weight based on the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid, and the gelling agent when forming the grease. Any unreacted water is substantially evaporated when forming the grease, so that water is not present in any significant amount (e.g., 1 wt% or less) in the finished grease.

[0081] 6. Complexing agent

[0082] In order to form a composite grease, the grease formulation can also include one or more complexing agents, such as complexing acids and / or their salts. Complexing acids can be selected from long-chain carboxylic acids or their calcium salts, short-chain carboxylic acids or their calcium salts, boric acid, borates, organic boron compounds, phosphoric acid, sulfonic acids and their mixtures. Suitable long-chain carboxylic acids include aliphatic carboxylic acids with 12 to 24 carbon atoms (such as at least 16 carbon atoms), and include 12-hydroxystearic acid (12-HSA) and oleic acid. Suitable short-chain carboxylic acids include aliphatic carboxylic acids with no more than 8 carbon atoms or no more than 4 carbon atoms, such as acetic acid. Suitable carboxylic acid calcium salts include calcium salts of hydrogenated castor oil, calcium salts of acetic acid and their mixtures. Suitable borated organic compounds include borated amines, borated amides, borated esters, borated alcohols, borated glycols, borated ethers, borated epoxides, borated ureas, borated carboxylic acids, borated sulfonic acids, borated epoxides, borated peroxides and their mixtures.

[0083] Suitable sulfonic acids include alkylbenzene sulfonic acids having alkyl chain lengths of 1 to 20 carbons. In one embodiment, the alkylbenzene sulfonic acid includes a mixture of alkyl chain lengths of 10 to 16 carbons. In one embodiment, the benzene sulfonic acid includes dodecylbenzene sulfonic acid ("DDBSA"). Commercially available benzene sulfonic acids of this type include JemPak from JePak GK Company. TM 1298 Sulfonic acid, Calsoft from Pilot Chemical Company TM LAS-99 and Biosoft from Stepan Chemical Company TM S-101.

[0084] The complexing agent may be present at 0.3 wt % to 15 wt % based on the final weight of the grease. In some embodiments, the complexing agent is at least 0.5 wt %, or at least 1 wt %, or at least 2 wt %, or up to 12 wt %, or up to 10 wt %, or up to 5 wt % of the total weight of the components used to form the composite grease. In another embodiment, the short chain carboxylic acid is present at 0.5 wt % to 2 wt % based on the final weight of the composite grease.

[0085] 7. Saponifier

[0086] Where the complexing agent is an acid rather than a salt, a strong calcium base (such as at least one of calcium oxide and calcium hydroxide) and / or calcium carbonate may be present in the grease formulation, for example in the form of slaked lime.

[0087] Sufficient saponifier may be added to form a complex soap structure. In particular, the saponifier may be present in an amount of 0.5 wt % to 8 wt % based on the final weight of the composite grease. In one embodiment, the saponifier may be at least 0.5 wt %, or at least 1 wt %, or at least 2 wt %, or at most 10 wt %, or at most 6 wt % of the total weight of the components used to form the composite grease.

[0088] 8. Performance additives

[0089] One or more performance additives may be incorporated into the grease. These performance additives may include at least one of antioxidants, antiwear agents, extreme pressure agents, friction modifiers, viscosity modifiers (which may include dispersant viscosity modifiers), metal passivators and / or corrosion inhibitors, and mixtures thereof. A fully formulated grease composition may contain one or more of these performance additives. Some performance additives may provide two or more of these functions.

[0090] In addition to the components of the grease composition described in (1) to (7), performance additives, if employed, may comprise at least 0.01 wt %, or at least 0.1 wt %, or up to 10 wt %, or up to 5 wt %, or up to 3 wt % of the grease.

[0091] (a) Antioxidants

[0092] The antioxidant may include, for example, phenates, phenate sulfides, sulfurized olefins, phosphorus-sulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyldiphenylamine, dinonyldiphenylamine, octyldiphenylamine, dioctyldiphenylamine), phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, macromolecular antioxidants, or mixtures thereof. A single antioxidant or a combination of two or more may be used.

[0093] Hindered phenol antioxidants may contain sec-butyl and / or tert-butyl groups as hindered groups. The phenol group may be further substituted by a hydrocarbyl group and / or a bridging group connected to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant may be an ester and may include, for example, an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl group may contain about 1 to about 18, or about 2 to about 12, or about 2 to about 8, or about 2 to about 6, or about 4 carbon atoms.

[0094] Other useful antioxidants may include diarylamines and high molecular weight phenols. In one embodiment, the grease composition may contain a mixture of diarylamines and high molecular weight phenols such that each antioxidant may be present in an amount sufficient to provide up to about 5 weight percent antioxidant based on the final weight of the grease composition. In some embodiments, the antioxidant may be a mixture of about 0.3 weight percent to about 1.5 weight percent diarylamine and about 0.4 weight percent to about 2.5 weight percent high molecular weight phenol based on the final weight of the grease composition.

[0095] The example of suitable olefin that can be sulfurized to form sulfurized olefin includes propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nineteendecene, eicosene or their mixture. In one embodiment, hexadecene, heptadecene, octadecene, nineteendecene, eicosene or their mixture and their dimer, trimer and tetramer are particularly useful olefins. Alternatively, olefin can be a diene (such as 1,3-butadiene) and an unsaturated ester (such as butyl acrylate) Diels-Alder (Diels-Alder) adduct.

[0096] Another class of sulphurized olefins includes sulphurized fatty acids and their esters. Fatty acids are usually obtained from vegetable oils or animal oils, and usually contain about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid or their mixtures. Fatty acids can be obtained from lard, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil or their mixtures. Fatty acids and / or esters can be mixed with olefins such as alpha-olefins.

[0097] When present, the one or more antioxidants may constitute in total at least 0.01 wt %, or at least 0.1 wt %, or at least 1 wt %, or at most 10 wt %, or at most 5 wt % of the grease composition.

[0098] (b) Antiwear agent

[0099] Examples of suitable antiwear agents include metal thiophosphates, metal dialkyl dithiophosphates, phosphates or salts thereof; phosphates; phosphites; phosphorus-containing carboxylates, ethers or amides; sulphurized olefins, thiocarbamate-containing compounds, including thiocarbamates, alkylene-coupled thiocarbamates and bis(S-alkyl dithiocarbamoyl) disulfides and mixtures thereof. Phosphorus-containing antiwear agents include dialkyl dithiophosphates of alkali metals, alkaline earth metals, aluminium, lead, tin, molybdenum, manganese, nickel, copper, titanium or zinc. Useful antiwear agents may be thiophosphates, such as zinc dialkyl dithiophosphates.

[0100] When present, one or more antiwear agents may total at least 0.01 wt %, or at least 0.1 wt %, or at least 0.5 wt %, or up to 10 wt %, or up to 5 wt %, or up to 3 wt % of the grease composition.

[0101] (c) Extreme pressure agent

[0102] Extreme pressure (EP) agents soluble in base oil include sulfur- and chlorine-sulfur-containing EP agents, chlorinated hydrocarbon EP agents, and phosphorus EP agents. Examples of such EP agents include chlorinated waxes; organic sulfides and polysulfides (such as dibenzyl disulfide, bis-(chlorobenzyl) disulfide, dibutyl tetrasulfide), methyl sulfide of oleic acid, sulfide of alkylphenols, sulfide of dipentenes, sulfide of terpenes, and sulfide of Diels-Alder adducts; phosphosulfurized hydrocarbons, such as the reaction product of phosphorus sulfide with turpentine or methyl oleate; phosphorus esters, such as dialkyl and trialkyl phosphites, for example, dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, amylphenyl phosphite, diamylphenyl phosphite, tridecyl phosphite, distearyl phosphite, and polypropylene-substituted phenyl phosphites; metal thiocarbamates, such as zinc dioctyldithiocarbamate and barium heptylphenol diacid; amine salts of alkyl and dialkyl phosphoric acids, such as the amine salt of the reaction product of dialkyldithiophosphoric acids with propylene oxide; and mixtures thereof.

[0103] When present, the one or more extreme pressure agents may total at least 0.01 wt %, or at least 0.1 wt %, or at least 0.5 wt %, or up to 10 wt %, or up to 5 wt %, or up to 3 wt % of the grease composition.

[0104] (d) Friction modifiers

[0105] Suitable friction modifiers include metal-containing and metal-free friction modifiers.

[0106] In one embodiment, the friction modifier may be an ashless friction modifier. Such friction modifiers are those friction modifiers that do not generally produce any sulfated ash when subjected to the conditions of ASTM D 874-13a (2018) "Standard Test Method for Sulfated Ash from Lubricating Oils and Additives". Example friction modifiers may include imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, aminoguanidines, alkanolamides, phosphonates, metal-containing compounds, glycerides, sulfurized fatty compounds and olefins, sunflower oil and other naturally occurring plant or animal oils, dicarboxylic acid esters, esters or partial esters of polyols with one or more aliphatic or aromatic carboxylic acids, and mixtures thereof.

[0107] Suitable friction modifiers may contain a hydrocarbon group selected from a straight chain, a branched chain or an aromatic hydrocarbon group or a mixture thereof and may be a saturated or unsaturated hydrocarbon group. The hydrocarbon group may be composed of carbon and hydrogen or heteroatoms (such as sulfur or oxygen). The hydrocarbon group may be in the range of about 12 to about 25 carbon atoms. In one embodiment, the friction modifier may be a long chain fatty acid ester. In one embodiment, the long chain fatty acid ester may be a monoester, or a diester, or a glycerol (tri) ester. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivative, or a long chain imidazoline.

[0108] Other suitable friction modifiers include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols, and typically include a polar end group (e.g., carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. An example of an organic ashless, nitrogen-free friction modifier is glyceryl monooleate (GMO), which may contain monoesters, diesters, and triesters of oleic acid.

[0109] Amine friction modifiers may include amines or polyamines. Such compounds may have straight chain, saturated or unsaturated or mixtures thereof and may contain aliphatic groups of 8 to 30 carbon atoms. Other examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are straight chain, saturated, unsaturated or mixtures thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

[0110] The amines and amides may be used as such or in the form of adducts or reaction products with boron compounds such as boron oxide, boron halides, metaborate, boric acid or mono-, di- or tri-alkyl borate.

[0111] When present, the one or more friction modifiers may total at least 0.01 wt %, or at least 0.1 wt %, or at least 0.5 wt %, or up to 10 wt %, or up to 5 wt %, or up to 4 wt % of the grease composition.

[0112] (e) Viscosity improver

[0113] Suitable viscosity improvers may include polyolefins, olefin copolymers, ethylene / propylene copolymers, polyisobutylene, hydrogenated styrene-isoprene polymers, styrene / maleate copolymers, hydrogenated styrene / butadiene copolymers, hydrogenated isoprene polymers, α-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrogenated alkenyl aryl conjugated diene copolymers, and mixtures thereof. The viscosity improver may include a star polymer, for example, as described in U.S. Publication No. 2012 / 0101017A1.

[0114] The grease composition may additionally or alternatively comprise one or more dispersant viscosity modifiers. Suitable dispersant viscosity modifiers include functionalized polyolefins, for example, ethylene-propylene copolymers that have been functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine; polymethacrylates functionalized with amines; esterified maleic anhydride-styrene copolymers reacted with amines, and mixtures thereof.

[0115] When present, the one or more viscosity modifiers comprise a total of at least 0.01 wt %, or at least 0.1 wt %, or at least 0.5 wt %, or up to 10 wt %, or up to 5 wt %, or up to 3 wt % of the grease composition.

[0116] (f) Corrosion inhibitors and metal passivators

[0117] Corrosion inhibitors / metal passivators that may be suitable for use in exemplary lubricating compositions include fatty amines, octylamine octanoate, condensation products of dodecenylsuccinic acid or anhydride and fatty acids (such as oleic acid with a polyamine), derivatives of benzotriazole (e.g., tolyltriazole), 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole, and 2-alkyldithiobenzothiazole.

[0118] When present, the one or more corrosion inhibitors / metal passivators may constitute in total at least 0.001 wt %, or at least 0.01 wt %, or at least 0.1 wt %, or up to 10 wt %, or up to 5 wt %, or up to 3 wt % of the grease composition.

[0119] Other additives

[0120] The grease formulation may contain minor amounts of other additives, for example, those present in commercial overbased calcium sulfonates, such as alcohols and / or other processing aids.

[0121] Preparation method of calcium sulfonate grease

[0122] In one embodiment, the overbased calcium sulfonate is prepared using a two-step process. In the first step ("promotion"), a stoichiometric excess of calcium oxide (CaO) or calcium hydroxide (Ca(OH)2) as an alkalinity source is combined with an alkylbenzene sulfonic acid, carbon dioxide (CO2), and optionally with other components to produce an oil-soluble overbased calcium sulfonate having amorphous calcium carbonate dispersed therein. In the second step ("conversion"), a gelling agent and water are added to the product of the promotion step together with a suitable base oil (such as mineral oil) to convert the amorphous calcium carbonate into a very finely divided dispersion of crystalline calcium carbonate, also called a colloidal dispersion, which interacts with the calcium sulfonate to form a grease-like consistency. This overbased calcium sulfonate grease produced by the two-step process may be referred to as a "simple calcium sulfonate grease".

[0123] In another embodiment, the one-step process combines the promotion step and the conversion step into a single step by carefully controlling the reaction. In this one-step process, a simple calcium sulfonate grease is prepared by reacting a sulfonic acid with calcium hydroxide or calcium oxide in the presence of a system of carbon dioxide and reagents, which acts as both a promoter (producing an overbased amorphous calcium carbonate by the reaction of carbon dioxide with excess calcium oxide or calcium hydroxide) and a gelling agent (converting amorphous calcium carbonate into very finely divided crystalline calcium carbonate). Thus, a grease-like consistency is formed in a single step, wherein the overbased oil-soluble calcium sulfonate (the product of the first step in the two-step process) is virtually never formed and separated into a separate product. The one-step process is disclosed in, for example, U.S. Patent Nos. 3,661,622, 3,671,012, 3,746,643, and 3,816,310.

[0124] In another embodiment, a calcium sulfonate grease is prepared using a preformed oil-soluble overbased calcium sulfonate. In this embodiment, a base oil is combined with an oil-soluble overbased calcium sulfonate, an acid (e.g., an alkylbenzene sulfonic acid), a gelling agent, and water, and these are mixed together at low temperature (less than 30° C., e.g., 18° C. to 23° C.) until an emulsion is formed, followed by heating to a gelling temperature (e.g., in the range of 89° C. to 94° C.), wherein the temperature is maintained until substantial or complete conversion of amorphous calcium carbonate to calcite occurs. Forming the emulsion at low temperature helps to avoid loss of water when the mixture is heated.

[0125] In another embodiment, a calcium sulfonate complex grease is prepared by adding a saponifying agent (e.g., a calcium-containing strong base such as calcium hydroxide or calcium oxide (e.g., as slaked lime)) to a simple calcium sulfonate grease produced by any of the above methods, and reacting the simple grease with a stoichiometric equivalent of one or more complexing acids such as 12-hydroxystearic acid (12-HSA), boric acid, acetic acid, and / or phosphoric acid, and optionally adding additional base oil. Further details on the preparation of calcium sulfonate complex greases are disclosed, for example, in U.S. Pat. Nos. 4,560,489, 5,126,062, 5,308,514, and 5,338,467.

[0126] The grease preparation method can be carried out in an open or closed kettle commonly used for grease manufacturing. The method can be achieved at standard atmospheric pressure, although it can be carried out under pressure in a closed kettle. In one embodiment, the method is carried out in an open kettle.

[0127] Example Grease Formulations

[0128] Table 1 illustrates examples of simple sulfonic acid grease formulations (not containing any performance additives, processing aids and solvents other than those listed), where the components are expressed as % by weight of the grease formulation. Table 2 illustrates examples of complex sulfonic acid grease formulations.

[0129] Table 1: Example Simple Grease Formulations

[0130]

[0131] Table 2: Compound grease formulations

[0132]

[0133] Properties of sulfonic acid grease

[0134] In one embodiment, the grease may have a consistency of a conventional grease as classified by the National Lubricating Grease Institute (NLGI). Conventional greases have an NLGI rating of 1 to 3, corresponding to a cone penetration of 230 to 340, as measured by ASTM D217-21a "Standard Test Methods for Cone Penetration of Lubricating Grease". In certain embodiments, the grease is a composite grease having a cone penetration of 230 to 340 as measured by ASTM D217-21a. In other embodiments, the composite grease has a cone penetration of 265 to 295 as measured by ASTM D217-21a.

[0135] By adding additional oil if necessary, a composite grease prepared from a simple grease can have comparable penetration scores, for example, within NLGI grades 1-3, and in certain embodiments within NLGI grades 2 or 3. In some embodiments, at least 90 wt. % or 95 wt. % of the amorphous calcium carbonate present in the grease formulation is converted, and the grease formulation is NLGI grade 2 or 3.

[0136] The dropping point of a lubricating grease is an indicator of the static heat resistance of the grease and is the temperature at which it may change from a semi-solid to a liquid state or ooze excess oil under specific test conditions. The dropping point indicates the upper temperature limit at which the grease retains its structure, although not necessarily the maximum temperature at which the grease may be used. In one embodiment, the composite grease has a dropping point of 260°C to 304°C (or above) as measured by ASTM D2265-22 "Standard Test Method for Dropping Point of Lubricating Grease Over Wide Temperature Range".

[0137] The composition of the grease can be characterized by Fourier Transform Infrared (FTIR) spectroscopy. In one embodiment, the infrared spectrum of an exemplary simple grease shows a wavelength of about 883 cm -1 The peak at about 864 cm-1 indicates the presence of the calcite allotrope of CaCO3. For conversions less than 100%, especially less than 95%, the peak at about 864 cm-1 indicates the presence of the calcite allotrope of CaCO3. -1 A second peak was observed at 883 cm-1, corresponding to residual amorphous calcium carbonate. The conversion percentage can be estimated at about 883 cm-1. -1 The area under the peak at 100 cm / s is divided by the area plus about 864 cm / s. -1 Calculate the area under the peak at , and multiply by 100.

[0138] In compound grease, at about 1569cm -1 The presence of a peak at is characteristic of a carbonyl peak and indicates incorporation of calcium acetate into the grease structure, with the relative intensity of the peak corresponding to the relative calcium acetate content of the batch.

[0139] The calcium sulfonate greases described herein do not readily separate oil or suffer from decomposition under shear, and therefore often have no problems in the ASTM D2265-22 dropping point test, the ASTM D217-21a "Standard Test Methods for Cone Penetration of Lubricating Grease" test, the oil separation test ASTM D1742-20, or the wheel bearing leakage test ASTM D4290-20. The grease also meets extreme pressure and anti-wear requirements, with a 4-ball weld load measured by ASTM D2596-20 exceeding 315 kg and a 4-ball wear scar measured by ASTM D2266-01 (2015) <0.4 mm. Synthetic sulfonate greases can be formulated to pass the ASTM D1743-22 corrosion test, and water washout is typically less than 5%, which is well below the 15% limit required by the standard. If a suitable base oil is used, there is generally no problem passing the ASTM D4693-07 (2021) low temperature torque test.

[0140] application

[0141] The calcium sulfonate greases described herein are found to be useful as high performance multipurpose (HPM) greases and high load bearing (HPM+HL) greases as defined by the NLGI. The greases are also found to be useful in applications requiring high temperatures and good load bearing capabilities, such as in ironworks applications, heavy industrial machinery, mining, and food manufacturing.

[0142] Without intending to limit the scope of the exemplary embodiments, the following examples illustrate exemplary grease compositions and comparative examples, which indicate the benefits obtained with illustrative gelling agents. Unless otherwise indicated, all amounts are on an oil-free basis and are by weight.

[0143] Example

[0144] Obtain the following materials:

[0145] - 400TBN synthetic overbased calcium sulfonate, 75GR, available from The Lubrizol Corporation. This material contains 20 wt% calcium sulfonate, 35 wt% calcium carbonate, 2 to 3 wt% lime, 40 wt% oil, and trace amounts (2 to 3 wt% total) of alcohol, water, and processing aids.

[0146] - 600N API Group II paraffinic mineral oil with a KV40 of 110 cSt, obtained from Chevron.

[0147] -BS150 Group I base oil with a KV40 of 500 cSt, sold under the trade name SunparTM Obtained from HollyFrontier.

[0148] -Mixed C 10 To C 16 Alkylbenzene sulfonic acid ("ABSA"), Biosoft TM S-101 was sold and obtained from Stepan Chemical Company.

[0149] -2-Ethyl-1,3-hexanediol and other OH sources were obtained from Gulf Chemical Inc.

[0150] -12-Hydroxystearic acid, obtained from Acme Hardesty.

[0151] - Acetic acid, obtained from Brenntag.

[0152] - Boric acid, obtained from U.S. Borax.

[0153] -Alkylated diphenylamine, GR9510, obtained from Lubrizol Corporation.

[0154] -water

[0155] Example 1

[0156] Calcium sulfonate compositions (some of which produced simple greases) were prepared as follows:

[0157] At room temperature (about 20° C.), 65.0 wt. % Lubrizol 75GR (containing 55 wt. % 400 TBN synthetic overbased oil-soluble calcium sulfonate), 27.5 wt. % 600N API Group II paraffinic mineral oil (KV40=110 cSt) (base oil), 5.0 wt. % alkylbenzene sulfonic acid (ABSA) and 2.5 wt. % candidate gelling agent were added to a 1.5 liter stainless steel open reactor with a heater and a wall scraper. 10 wt. % water was added thereto. The contents of the reactor were mixed until an emulsion was formed. The mixture was then heated to 90° C. and maintained until the material gelled, or for 2 hours, whichever was longer. The extent of conversion was confirmed by FTIR spectroscopy. Most of the water and candidate gelling agent were stripped out by heating the mixture to 150° C., holding for 30 minutes, and then allowing the mixture to cool. The consistency (penetration rating) was determined and the dropping point was measured.

[0158] The conversion of amorphous calcium carbonate to crystalline forms (mainly calcite) was estimated from FTIR spectroscopy. -1As the conversion proceeds, the broad band shrinks and becomes larger in the spectrum at about 883 cm -1 When the conversion rate is 100%, there is no amorphous band, and the peak at about 883 cm -1 Only a single large peak was observed at . To determine the % conversion, estimate and calculate the peaks (864 cm -1 and 883cm -1 ) below.

[0159] The results are shown in Table 3.

[0160] Under the NLGI grading system, a worked penetration range of 355 to 385 (determined according to ASTM D217-21a) is Class 0, 310 to 340 is Class 1, 265 to 295 is Class 2, and 220 to 250 is Class 3.

[0161] Table 3 :

[0162] OH Source Conversion rate%, time Observations NLGI Grade Control (no OH source) 0 liquid - 2-Ethyl-1,3-hexanediol 100%, 45 minutes thick 2 2-Methyl-2,4-pentanediol 90%, 1 hour thick 2 2-Butyl-2-ethyl-propylene glycol 100%, 30 minutes Very thick 2 2,5-Dimethyl-2,5-hexanediol 90%, 1 hour Very thick 3 1,2-Octanediol 60%, 2 hours Very rare 0 1,2-Hexanediol 85%, 2 hours Thin gel 1 1,6-Hexanediol 0%, 2 hours liquid 0 Diethylene glycol monobutyl ether 80%, 1 hour Thick gel 2 Diethylene glycol monomethyl ether 0%, 1 hour liquid - Dodecanol 0%, 2 hours liquid - 2(2-ethylhexyloxy)ethanol 0%, 2 hours liquid - 2-Methyl-1,3-butanediol 80%, 1 hour gel 2 Methoxypolyethylene glycol 0%, 2 hours liquid -

[0163] Based on the results, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-propylene glycol, and 2,5-dimethyl-2,5-hexanediol appear to completely convert to thick gels in less than one hour. As gel formers, these branched 8-carbon diols perform better than comparative unbranched diols.

[0164] Example 2

[0165] Calcium sulfonate complex grease was prepared as follows:

[0166] Example 2A :

[0167] Add 418 g Lubrizol 75GR (20 wt % 400TBN synthetic overbased calcium sulfonate) to the reactor followed by 108.4 g Group II 600N base oil and 108.4 g BS150 base oil. Heat the mixture to 50°C. Mix 11.5 g glacial acetic acid with 100 g water and add. Add 9.9 g 2-ethyl-1,3-hexanediol and slowly add 37 g alkylbenzene sulfonic acid. Raise the temperature to 90°C and hold for 1 hour or until FTIR indicates complete conversion. Capture the FTIR spectrum.

[0168] After conversion, complexation is performed. Another 108.4 g base oil and 108.4 g BS150 oil are added, followed by 30.2 g slaked lime, 25.2 g boric acid and 100 g water. The mixture is mixed for 30 minutes to properly incorporate. The temperature is raised to 140°C to 150°C and maintained for 1 hour to dehydrate. Once dehydration is complete, 34.2 g 12-hydroxystearic acid is added. After 0.5 hours, the mixture is cooled to 80°C. Once the mixture is at 80°C, 5 g Lubrizol GR9510 antioxidant (alkylated diphenylamine) is added. The grease is homogenized using a three-roll mill and the needle penetration and dropping point of the grease are checked. If the grease is too hard, additional oil is added and mixed. Repeat this step until the grease is within the desired NLGI grade.

[0169] Comparative Example 2B :

[0170] The procedure of Example 2A was repeated except that 9.9 g of diethylene glycol butyl ether was used instead of 2-ethyl-1,3-hexanediol.

[0171] Table 4 shows the two formulations.

[0172] Table 4: Compound grease formulations

[0173]

[0174]

[0175] Table 5 shows the obtained results.

[0176] Table 5: Results

[0177]

[0178] The conversion was measured via FTIR. 2-Ethyl-1,3-hexanediol was fully converted, while diethylene glycol butyl ether had a maximum conversion of 85% at the end. Both gelling aids showed no decrease when measured according to ASTM D2265.

[0179] Diethylene glycol butyl ether exhibited a Worked 60 Cone Penetration variation of 28, which is greater than typically expected (a variation of < 15 is typically considered acceptable).

[0180] Each of the above-mentioned documents is incorporated herein by reference in its entirety.Unless in the examples or otherwise clearly indicated, all numerical values ​​of the amount of a given substance, reaction conditions, molecular weight, number of carbon atoms, etc. in this specification sheet should be understood to be modified by the word "about".Unless otherwise indicated, each chemical or composition mentioned herein should be interpreted as a commercial grade material, which may contain isomers, by-products, derivatives and other such materials generally understood to be present in the commercial grade.However, unless otherwise indicated, the amount of each chemical component does not include any solvent or diluent oil, which may be present in commercial materials generally.It should be understood that the upper and lower limits of the amount, range and ratio described herein may be independently combined.Similarly, the scope and amount of each element of the present invention may be used together with the scope or amount of any other element.

[0181] It should be understood that the above disclosed and other features and functions of the variant or its alternatives can be combined into many other different systems or applications. Various currently unforeseen or unanticipated alternatives, modifications, changes or improvements may be subsequently made by those skilled in the art, and are also intended to be covered by the appended claims.

Claims

1. A calcium sulfonate grease, the calcium sulfonate grease being formed from a base oil of lubricating viscosity, an oil-soluble overbased calcium sulfonate or a precursor thereof, a conversion acid and a gelling agent selected from a branched aliphatic diol having at least eight carbon atoms and mixtures thereof.

2. The calcium sulfonate grease according to claim 1, wherein the gelling agent is selected from branched aliphatic diols having eight to ten carbons.

3. The calcium sulfonate grease according to claim 1 or 2, wherein the gelling agent is selected from the group consisting of a branched aliphatic diol having eight carbons, a branched aliphatic diol having nine carbons, and mixtures thereof.

4. The calcium sulfonate grease according to any one of claims 1 to 3, wherein the gelling agent comprises at least one of the group consisting of 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-propylene glycol, 2,5-dimethyl-2,5-hexanediol, and combinations thereof.

5. The calcium sulfonate grease according to any one of claims 1 to 4, wherein the gelling agent is at least 0.5 wt%, or at least 1 wt%, or at most 5 wt%, or at most 3 wt%, of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent.

6. The calcium sulfonate grease according to any one of claims 1 to 5, wherein the gelling agent comprises 2-ethyl-1,3-hexanediol.

7. The calcium sulfonate grease of claim 6, wherein the 2-ethyl-1,3-hexanediol is at least 0.5 wt% of the combined weight of the base oil, the oil-soluble overbased calcium sulfonate or precursor thereof, the conversion acid and the gelling agent.

8. A calcium sulphonate grease according to claim 6 or claim 7 wherein the gelling agent consists essentially of 2-ethyl-1,3-hexanediol.

9. A calcium sulfonate grease according to any one of claims 1 to 8, wherein the oil-soluble overbased calcium sulfonate has a total base number (TBN) as measured according to ASTM D2896 of at least 300 mg KOH / g eq, or at least 350 mg KOH / g eq, or at most 600 mg KOH / g eq, or at most 500 mg KOH / g eq.

10. The calcium sulfonate grease according to any one of claims 1 to 9, wherein the oil-soluble overbased calcium sulfonate comprises a calcium salt of a sulfonic acid selected from alkyl sulfonic acids, aryl sulfonic acids, alkyl aryl sulfonic acids and mixtures thereof.

11. A calcium sulfonate grease according to any one of claims 1 to 10, wherein the oil-soluble overbased calcium sulfonate comprises a calcium salt of a sulfonic acid comprising at least 10, or at least 12, or at least 20 aliphatic carbon atoms, or at most 36, or at most 30 aliphatic carbon atoms.

12. The calcium sulfonate grease according to any one of claims 1 to 11, wherein the oil-soluble overbased calcium sulfonate comprises a calcium salt of a sulfonic acid selected from the group consisting of dodecylbenzenesulfonic acid, didodecylbenzenesulfonic acid, dinonylbenzenesulfonic acid, dinonylsubstituted naphthalenesulfonic acid, petroleum sulfonic acid, monowax (eicosane) substituted naphthalenesulfonic acid, octadecyldiphenyl ethersulfonic acid, octadecyldiphenylaminesulfonic acid, hexadecylchlorobenzenesulfonic acid, dilauryl β-naphthalenesulfonic acid, sulfonic acid derived by treating polyisobutylene with chlorosulfonic acid, nitronaphthalenesulfonic acid, paraffinsulfonic acid, hexadecylcyclopentanesulfonic acid, laurylcyclohexanesulfonic acid, polyethylenesulfonic acid, and mixtures thereof.

13. A calcium sulfonate grease according to any one of claims 1 to 12, wherein the oil-soluble overbased calcium sulfonate comprises a synthetic calcium salt of an alkylbenzene sulfonic acid containing at least one C8-C36 alkyl group.

14. A calcium sulfonate grease according to any one of claims 1 to 13, wherein the oil-soluble overbased calcium sulfonate comprises calcium carbonate.

15. A calcium sulfonate grease according to any one of claims 1 to 14, wherein the oil-soluble overbased calcium sulfonate is at least 3 wt%, or at least 5 wt%, or at least 8 wt%, or at most 25 wt%, or at most 20 wt%, or at most 15 wt%, of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent.

16. A calcium sulfonate grease according to any one of claims 1 to 15, wherein the conversion acid is selected from alkylbenzenesulfonic acids having an aliphatic chain of 8 to 36 carbon atoms, succinic acid having an aliphatic chain of 8 to 36 carbon atoms, succinic acid having an alkyl or alkenyl group at C2 or C3 of the succinic acid and having an aliphatic chain of 8 to 36 carbon atoms, and mixtures thereof.

17. A calcium sulfonate grease according to any one of claims 1 to 16, wherein the conversion acid is at least 1 wt%, or at least 3 wt%, or at least 4 wt%, or at most 15 wt%, or at most 12 wt%, of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent.

18. A calcium sulfonate grease according to any one of claims 1 to 17, wherein the base oil of lubricating viscosity is at least 40 wt%, or at least 50 wt%, or at least 60 wt%, or at most 90 wt%, or at most 80 wt% of the total weight of the base oil, the oil-soluble overbased calcium sulfonate or precursor thereof, the conversion acid and the gelling agent.

19. The calcium sulfonate grease according to any one of claims 1 to 18, wherein the calcium sulfonate grease is further formed from water.

20. The calcium sulfonate grease according to claim 19, wherein the water is added at 2 to 25 parts by weight based on the total weight of the base oil, the oil-soluble overbased calcium sulfonate or its precursor, the conversion acid and the gelling agent.

21. The calcium sulfonate grease according to any one of claims 1 to 20, wherein the calcium sulfonate grease is a calcium sulfonate complex grease, and wherein the calcium sulfonate complex grease is further prepared by at least one of a complexing agent and a saponifying agent.

22. The calcium sulfonate complex grease according to claim 21, wherein the complexing agent is selected from the group consisting of long chain carboxylic acids or calcium salts thereof, short chain carboxylic acids or calcium salts thereof, boric acid, its salts and organic boron compounds, phosphoric acid, sulfonic acid and mixtures thereof.

23. A calcium sulfonate complex grease according to claim 21 or claim 22, wherein the complexing agent is at least 0.5 wt%, or at least 1 wt%, or at least 2 wt%, or at most 12 wt%, or at most 10 wt% of the total weight of the complex grease.

24. The calcium sulfonate complex grease according to any one of claims 21 to 23, wherein the saponifying agent is selected from the group consisting of calcium oxide, calcium hydroxide, calcium carbonate and mixtures thereof.

25. The calcium sulfonate complex grease according to any one of claims 21 to 24, wherein the saponifier is at least 0.5 wt%, or at least 1 wt%, or at least 2 wt%, or at most 10 wt%, or at most 6 wt% of the total weight of the complex grease.

26. The calcium sulfonate grease according to any one of claims 1 to 25, further comprising at least one performance additive selected from the group consisting of antioxidants, antiwear agents, extreme pressure agents, friction modifiers, viscosity modifiers, metal deactivators and / or corrosion inhibitors and mixtures thereof.

27. The calcium sulfonate grease of claim 26, wherein the at least one performance additive totals at least 0.01 wt%, or at least 0.1 wt%, or at most 10 wt%, or at most 5 wt%, or at most 3 wt% of the calcium sulfonate grease.

28. A method for lubricating a device, the method comprising applying a calcium sulphonate grease according to any one of claims 1 to 27 to the device.

29. Use of the calcium sulfonate grease according to any one of claims 1 to 27 for lubricating a device.

30. A method of forming a calcium sulfonate grease, the method comprising: combining a base oil of lubricating viscosity, an oil-soluble overbased calcium sulfonate or a precursor thereof, a conversion acid, a gelling agent, and water to form a mixture, wherein the gelling agent is selected from the group consisting of branched aliphatic diols having at least eight carbons and mixtures thereof; and The mixture is heated to a gelling temperature at which the mixture forms a gel.

31. The method of claim 30, wherein the mixture is an emulsion and is formed at a temperature below 30°C.

32. The method of claim 30 or 31 further comprising incorporating at least one of a complexing agent and a saponifying agent into the gel to form a calcium sulfonate complex grease.

33. A formulation for forming a calcium sulfonate grease, the formulation comprising: 3 to 20 wt % overbased calcium sulfonate; 1 to 12 wt % conversion acid; 0.5 to 6 wt % of a gelling agent; 2 to 25 wt % water; and At least 30% by weight of base oil.

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