Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
  • C10M159/12—Reaction products
  • C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products
  • C10M159/24—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing sulfonic radicals
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
  • C10M2201/06—Metal compounds
  • C10M2201/062—Oxides; Hydroxides; Carbonates or bicarbonates
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
  • C10M2219/08—Thiols; Sulfides; Polysulfides; Mercaptals
  • C10M2219/082—Thiols; Sulfides; Polysulfides; Mercaptals containing sulfur atoms bound to acyclic or cycloaliphatic carbon atoms
  • C10M2219/087—Thiols; Sulfides; Polysulfides; Mercaptals containing sulfur atoms bound to acyclic or cycloaliphatic carbon atoms containing hydroxy groups; Derivatives thereof, e.g. sulfurised phenols
  • C10M2219/089—Overbased salts
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2050/00—Form in which the lubricant is applied to the material being lubricated
  • C10N2050/10—Semi-solids; greasy
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2070/00—Specific manufacturing methods for lubricant compositions

Definitions

• This invention relates to overbased calcium sulfonate greases made with the addition of an alkali metal hydroxide to provide improvements in both thickener yield and expected high temperature utility as demonstrated by dropping point, even when the oil-soluble overbased calcium sulfonate used to make the grease is considered to be of poor quality.
• This invention also related to overbased calcium sulfonate greases made with both added alkali metal hydroxide and delayed addition of non-aqueous converting agents.
• Overbased calcium sulfonate greases have been an established grease category for many years.
• One known process for making such greases is a two-step process involving the steps of "promotion” and “conversion.”
• the first step is to react a stoichiometric excess amount of calcium oxide (CaO) or calcium hydroxide (Ca(OH) 2 ) as the base source with an alkyl benzene sulfonic acid, carbon dioxide (CO 2 ), and with other components to produce an oil-soluble overbased calcium sulfonate with amorphous calcium carbonate dispersed therein.
• These overbased oil-soluble calcium sulfonates are typically clear and bright and have Newtonian rheology.
• overbased oil-soluble calcium sulfonate and “oil-soluble overbased calcium sulfonate” and “overbased calcium sulfonate” refer to any overbased calcium sulfonate suitable for making calcium sulfonate greases.
• the second step (“conversion”) is to add a converting agent or agents, such as propylene glycol, iso-propyl alcohol, water, formic acid or acetic acid, to the product of the promotion step, along with a suitable base oil (such as mineral oil) if needed to keep the initial grease from being too hard, to convert the amorphous calcium carbonate contained in the overbased calcium sulfonate to a very finely divided dispersion of crystalline calcium carbonate (calcite).
• a converting agent or agents such as propylene glycol, iso-propyl alcohol, water, formic acid or acetic acid
• acetic acid or other acids When acetic acid or other acids are used as a converting agent, typically water and another non-aqueous converting agent (a third converting agent, such as an alcohol) are also used; alternatively only water (without the third converting agent) is added, but the conversion then typically occurs in a pressurized vessel. Because an excess of calcium hydroxide or calcium oxide is used to achieve overbasing, a small amount of residual calcium oxide or calcium hydroxide may also be present as part of the oil soluble overbased calcium sulfonate and will be dispersed in the initial grease structure. The extremely finely divided calcium carbonate formed by conversion, also known as a colloidal dispersion, interacts with the calcium sulfonate to form a grease-like consistency.
• a third converting agent such as an alcohol
• overbased calcium sulfonate greases produced through the two-step process have come to be known as "simple calcium sulfonate greases" and are disclosed, for example, in U.S. Pat. Nos. 3,242,079 ; 3,372,115 ; 3,376,222 , 3,377,283 ; and 3,492,231 .
• the simple calcium sulfonate grease is prepared by reaction of an appropriate sulfonic acid with either calcium hydroxide or calcium oxide in the presence of carbon dioxide and a system of reagents that simultaneously act as both promoter (creating the amorphous calcium carbonate overbasing by reaction of carbon dioxide with an excess amount of calcium oxide or calcium hydroxide) and converting agents (converting the amorphous calcium carbonate to very finely divided crystalline calcium carbonate).
• the 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 never actually formed and isolated as a separate product.
• This one-step process is disclosed, for example, in U.S. Patent Nos. 3,661,622 ; 3,671,012 ; 3,746,643 ; and 3,816,310 .
• calcium sulfonate complex greases are also known in the prior art. These complex greases are typically produced by adding a strong calcium-containing base, such as calcium hydroxide or calcium oxide, to the simple calcium sulfonate grease produced by either the two-step or one-step process and reacting with up to stoichiometrically equivalent amounts of complexing acids, such as 12- hydroxystearic acid, boric acid, acetic acid (which may also be a converting agent when added pre-conversion), or phosphoric acid.
• complexing acids such as 12- hydroxystearic acid, boric acid, acetic acid (which may also be a converting agent when added pre-conversion), or phosphoric acid.
• the claimed advantages of the calcium sulfonate complex grease over the simple grease include reduced tackiness, improved pumpability, and improved high temperature utility. Calcium sulfonate complex greases are disclosed, for example, in U.S. Patent Nos. 4,560,489 ; 5,126,062 ; 5,
• the resulting grease contains greater than 38% overbased calcium sulfonate and the '489 patent points out that the ideal amount of overbased calcium sulfonate for the processes disclosed therein is around 41-45%, since according to the '489 patent using less than 38% results in a soft grease.
• the resulting grease of example 1 in the '489 patent has a dropping point of around only 299°C (570°F).
• the '489 patent does not state the duration of delay between the addition of water and the addition of the non-aqueous converting agents, but indicates that the addition was immediate after a period of heating from 66°C to just 88°C (150 F to just 190 F).
• the dropping point and thickener yield in the '489 patent are not desirable.
• U.S. Patent Nos. 5,338,467 and 5,308,514 disclose the use of a fatty acid, such as 12-hydroxystearic acid, as a converting agent used along with acetic acid and methanol, where there is no delay for the addition of the fatty acid but some interval between the addition of water and the addition of acetic acid and methanol.
• Example B in the '514 patent and example 1 in the '467 patent both describe a process where water and the fatty acid converting agent are added to other ingredients (including the overbased calcium sulfonate and base oil), then heated to around 60-63°C (140-145°F) before adding acetic acid followed by methanol.
• the known prior art always teaches the use of calcium oxide or calcium hydroxide as the sources of basic calcium for production of calcium sulfonate greases or as a required component for reacting with complexing acids to form calcium sulfonate complex greases.
• the known prior art teaches that the addition of calcium hydroxide or calcium oxide needs to be in an amount sufficient (when added to the amount of calcium hydroxide or calcium oxide present in the overbased oil-soluble calcium sulfonate) to provide a total level of calcium hydroxide or calcium oxide sufficient to fully react with the complexing acids.
• the known prior art generally teaches that the presence of calcium carbonate (as a separate ingredient or as an "impurity" in the calcium hydroxide or calcium oxide, other than that presence of the amorphous calcium carbonate dispersed in the calcium sulfonate after carbonation), should be avoided for at least two reasons.
• the first being that calcium carbonate is generally considered to be a weak base, unsuitable for reacting with complexing acids to form optimum grease structures.
• the second being that the presence of unreacted solid calcium compounds (including calcium carbonate, calcium hydroxide or calcium oxide) interferes with the conversion process, resulting in inferior greases if the unreacted solids are not removed prior to conversion or before conversion is completed.
• nano-sized particles would add to the thickening of the grease to keep it firm, much like the fine dispersion of crystalline calcium carbonate formed by converting the amorphous calcium carbonate contained within the overbased calcium sulfonate (which can be around 20 A to 5000A or around 2 nm to 500 nm according to the '467 patent), but would also substantially increase the costs over larger sized particles of added calcium carbonate.
• This Chinese patent application greatly emphasizes the absolute necessity of the added calcium carbonate having a true nano particle size.
• superior greases may be formed by the addition of micron sized calcium carbonate without requiring the use of the very expensive nano-sized particles and when using added calcium carbonate as one of or the sole added calcium containing base for reacting with complexing acids.
• hydroxyapatite is disclosed as a mixture of tricalcium phosphate and calcium hydroxide, which is not the same as the calcium hydroxyapatite disclosed and claimed in the ⁇ 768 application and herein having the formula Ca 5 (PO 4 ) 3 OH or a mathematically equivalent formula with a melting point of around 1100 C.
• calcium hydroxyapatite, tricalcium phosphate, and calcium hydroxide are each distinct chemical compounds with different chemical formulae, structures, and melting points.
• tricalcium phosphate having the formula Ca 3 (PO 4 ) 2
• calcium hydroxide Ca(OH) 2
• the melting point of tricalcium phosphate is 1670 C.
• Calcium hydroxide does not have a melting point, but instead loses a water molecule to form calcium oxide at 580 C.
• the calcium oxide thus formed has a melting point of 2580 C.
• Calcium hydroxyapatite (having the formula Ca 5 (PO 4 ) 3 OH or a mathematically equivalent formula) has a melting point of around 1100 C. Therefore, regardless of how inaccurate the nomenclature may be, calcium hydroxyapatite is not the same chemical compound as tricalcium phosphate, and it is not a simple blend of tricalcium phosphate and calcium hydroxide.
• alkali metal hydroxides in simple calcium soap greases, such as anhydrous calcium-soap thickened greases, is also known. But it is not known to add an alkali metal hydroxide in a calcium sulfonate grease to provide improved thickener yield and high dropping point, because that addition would be considered unnecessary by one of ordinary skill in the art.
• the reason for adding an alkali metal hydroxide, such as sodium hydroxide, in simple calcium soap greases is that the usually used calcium hydroxide has poor water solubility and is a weaker base than the highly water soluble sodium hydroxide.
• a complex calcium sulfonate grease composition comprises an alkali metal hydroxide.
• a complex calcium sulfonate grease composition comprises an alkali metal hydroxide and calcium hydroxyapatite, added calcium carbonate, or both as added calcium containing bases (also referred to as basic calcium compounds) for reaction with complexing acids.
• a complex calcium sulfonate grease composition comprises (1) less than 36% (by weight of the final grease) overbased calcium sulfonate; (2) calcium hydroxyapatite, added calcium carbonate, calcium hydroxide, calcium oxide, or any combination thereof; (3) one or more alkali metal hydroxides; (4) one or more converting agents; and (5) one or more complexing acids.
• the final grease composition comprises around 0.005% to 0.5% alkali metal hydroxide.
• an alkali metal hydroxide is added to other ingredients prior to or after conversion.
• the method comprises (a) mixing overbased calcium sulfonate and a base oil; (b) adding and mixing one or more calcium containing bases; (c) dissolving an alkali metal hydroxide in water and adding and mixing the solution with the other ingredients; (d) adding and mixing one or more converting agents, which may include the water from step c if added prior to conversion; (e) adding and mixing one or more complexing acids; and (f) heating some combination of these ingredients until conversion has occurred.
• Each of the ingredients in steps (b), (c), and (e) can be added prior to conversion, after conversion, or a portion added prior to and another portion added after conversion, and their order relative to each other is not critical for this embodiment of the method.
• a complex calcium sulfonate grease is produced by reacting and mixing certain compounds according to the steps outline above, except that a first portion of water is added as a converting agent prior to conversion and a second portion of water is added after conversion and the alkali metal hydroxide is dissolved in the first portion of water or the second portion of water or both.
• water is added in at least two separate pre-conversion steps as a converting agent, with one or more temperature adjustment steps, addition of another ingredient(s) steps or a combination thereof between the first addition of water as a converting agent and the second addition of water as a converting agent and the alkali metal hydroxide is dissolved in the initial or first addition of water as a converting agent, or the second or subsequent addition of water as a converting agent, or both.
• a method for producing a complex calcium sulfonate grease comprises the steps outlined above, including preferred embodiment variations, wherein the converting agents comprise water and at least one non-aqueous converting agent and wherein there is one or more delay periods between the addition of water as a converting agent and the addition of at least a portion of a non-aqueous converting agent.
• the one or more of the delay periods is a temperature adjustment delay period or a holding delay period or both, as further described below.
• non-aqueous converting agent means any converting agent other than water and includes converting agents that may contain some water as a diluent or an impurity.
• all of one or more the complexing acids may be added prior to conversion or after conversion.
• a portion of one of more of the complexing acids may be added prior to conversion of the complex calcium sulfonate grease, with the remainder of the one or more complexing acids added after conversion.
• All of the one or more calcium containing bases may be added prior to conversion or after conversion.
• a portion of one or more of the calcium containing bases may be added prior to conversion, with the remainder added after conversion.
• Calcium hydroxyapatite, added calcium carbonate, added calcium hydroxide, added calcium oxide, or a combination thereof may be used as the calcium containing bases for reacting with the complexing acids.
• improved thickener yield results are achieved using added alkali metal hydroxide, either alone or in combination with at least one delay period for at least a portion of a non-aqueous converting agent, even when the overbased calcium sulfonate is considered to be of "poor quality.”
• Certain overbased oil-soluble calcium sulfonates marketed and sold for the manufacture of calcium sulfonate-based greases can provide products with unacceptably low dropping points when prior art calcium sulfonate technologies are used. Such overbased oil-soluble calcium sulfonates are referred to as "poor quality" overbased oil-soluble calcium sulfonates throughout this application.
• overbased oil-soluble calcium sulfonates producing greases having higher dropping points are considered to be "good” quality calcium sulfonates for purposes of this invention and those producing greases having lower dropping points are considered to be “poor” quality for purposes of this invention.
• Several examples of this are provided in the ⁇ 768 application. Although comparative chemical analyses of good quality and poor quality overbased oil-soluble calcium sulfonates has been performed, it is believed that the precise reason for this low dropping point problem has not been proven.
• the non-aqueous converting agents is a glycol (e.g. propylene glycol or hexylene glycol)
• all of the glycol is added after at least one delay period (none is added with the water) and a poor quality calcium sulfonate is used.
• consistently high quality calcium sulfonate greases may be made with thickener yield and dropping point properties superior to those of prior art greases.
• the overbased calcium sulfonate complex greases made according to preferred embodiments of the invention have an NLGI No. 2 grade consistency (or better, i.e. harder) and a dropping point of 302°C (575° F) (or higher), with the percentage of overbased oil-soluble calcium sulfonate being between about 10% and 45% when made in an open vessel (without pressure).
• the amount of overbased oil-soluble calcium sulfonate in greases made according to preferred embodiments of the invention is at least around 10% but around 36% or less, more preferably around 30% or less, and most preferably around 22% or less when made in an open vessel (without pressure).
• These improved thickener yields are achievable with both good quality and poor quality overbased calcium sulfonates. Even greater thickener yield may be achieved with the ingredients and methods of the invention when the grease is made in a pressurized vessel. Most preferably a dropping point in excess of 343°C (650 F) is achieved.
• the lower concentrations of the overbased oil-soluble calcium sulfonate achieved by the invention are desirable since the cost of the grease is reduced. Other properties such as mobility and pumpability, especially at lower temperatures, may also be favorably impacted by the improved thickener yield achieved according to the invention.
• alkali metal hydroxide results in a looping metathesis reaction that impacts the conversion process and the reaction with complexing acids to produce these unexpected thickener yield and dropping point results in complex calcium sulfonate greases.
• alkali metal hydroxides are known to be added to simple calcium soap greases, but not to complex overbased calcium sulfonate greases. This is because the usually used calcium hydroxide in the simple calcium soap grease has poor water solubility and is a weaker base compared to the highly water soluble sodium hydroxide.
• the small amount of sodium hydroxide dissolved in the added water is said to react quickly with the soap forming fatty acid (usually 12-hydroxystearic acid or a mixture of 12-hydroxystearic acid and a non-hydroxylated fatty acid such as oleic acid) to form the sodium soap.
• This quick reaction is thought to "get the ball rolling" in the manufacture of a simple calcium soap grease.
• the small amount of sodium hydroxide reacts with a small amount of the fatty acid, it leaves the remaining reactants (calcium hydroxide and the remaining majority of the fatty acid) to react as if no sodium hydroxide had ever been added.
• the unreacted calcium hydroxide will still be present and will still have to react with the remaining unreacted fatty acid to form the calcium soap thickener.
• compositions and method of the invention use the addition of an alkali metal hydroxide as an ingredient in a complex calcium sulfonate grease alone or in combination with (1) use of calcium hydroxyapatite and/or calcium carbonate as calcium containing bases for reacting with complexing acids and/or (2) one or more delay periods between the addition of water as a converting agent and the addition of at least a portion of a non-aqueous converting agent.
• a complex calcium sulfonate grease composition comprises the following ingredients: (1) 10% to 45% (by weight of the final grease) overbased calcium sulfonate; (2) calcium hydroxyapatite, added calcium carbonate, calcium hydroxide, calcium oxide, or any combination thereof; and (3) an alkali metal hydroxide. More preferably, the complex calcium sulfonate grease also comprises (4) one or more converting agents; and (5) one or more complexing acids.
• the one or more converting agents comprise water and at least one non-aqueous converting agent, such as propylene glycol or hexylene glycol.
• the grease composition may also comprise a facilitating acid. Such facilitating acid aids in grease structure formation. Some or all of any particular ingredient, including converting agents and calcium containing bases, may not be in the final finished product due to evaporation, volatilization, or reaction with other ingredients during manufacture.
• the highly overbased oil-soluble calcium sulfonate used according to these embodiments of the invention can be any typical to that documented in the prior art, such as U.S. Pat Nos. 4,560,489 ; 5,126,062 ; 5,308,514 ; and 5,338,467 .
• the highly overbased oil-soluble calcium sulfonate may be produced in situ according to such known methods or may be purchased as a commercially available product.
• Such highly overbased oil-soluble calcium sulfonates will have a Total Base Number (TBN) value not lower than 200, preferably not lower than 300, and most preferably about 400 or higher.
• TBN Total Base Number
• overbased calcium sulfonates of this type include the following: Hybase C401 as supplied by Chemtura USA Corporation; Syncal OB 400 and Syncal OB405-WO as supplied by Kimes Technologies International Corporation; Lubrizol 75GR, Lubrizol 75NS, Lubrizol 75P, and Lubrizol 75WO as supplied by Lubrizol Corporation.
• the overbased calcium sulfonate contains around 28% to 40% dispersed amorphous calcium carbonate by weight of the overbased calcium sulfonate, which is converted to crystalline calcium carbonate during the process of making the calcium sulfonate grease.
• the overbased calcium sulfonate also contains around 0% to 8% residual calcium oxide or calcium hydroxide by weight of the overbased calcium sulfonate.
• overbased calcium sulfonates will also contain around 40% base oil as a diluent, to keep the overbased calcium sulfonate from being so thick that it is difficult to handle and process.
• the amount of base oil in the overbased calcium sulfonate may make it unnecessary to add additional base oil (as a separate ingredient) prior to conversion to achieve an acceptable grease.
• the overbased calcium sulfonate used may be of a good quality or a poor quality as defined herein and in the ⁇ 768 application.
• the amount of the highly overbased oil-soluble calcium sulfonate in the final complex grease is between 10 and 45%.
• the amount of the highly overbased oil-soluble calcium sulfonate in the final complex grease according to an embodiment of the invention is around 36% or less, more preferably around 30% or less, and most preferably around 22% or less when made in an open vessel (without pressure), with even smaller percentages achievable when made in pressurized vessels.
• Base oil is added as needed, since most commercial overbased calcium sulfonates will already contain about 40% base oil as a diluent so as to prevent the overbased sulfonate from being so thick that it cannot be easily handled, it may be unnecessary to add additional base oil depending on the desired consistency of the grease immediately after conversion as well as the desired consistency of the final grease.
• Synthetic base oils may also be used in the greases of the present invention.
• Such synthetic base oils include polyalphaolefins (PAO), diesters, polyol esters, polyethers, alkylated benzenes, alkylated naphthalenes, and silicone fluids.
• PAO polyalphaolefins
• synthetic base oils may have an adverse effect if present during the conversion process as will be understood by those of ordinary skill in the art.
• those synthetic base oils should not be initially added, but added to the grease making process at a stage when the adverse effects will be eliminated or minimized, such as after conversion.
• Naphthenic and paraffinic mineral base oils are preferred due to their lower cost and availability.
• the total amount of base oil added (including that initially added and any that may be added later in the grease process to achieve the desired consistency) will typically be between 30% and 70%, preferably 45% and 70%, most preferably 50% and 70%, based on the final weight of the grease.
• the amount of base oil added as a separate ingredient will increase as the amount of overbased calcium sulfonate decreases.
• Combinations of different base oils as described above may also be used in the invention, as will be understood by those with ordinary skill in the art.
• Non-aqueous converting agents include any converting agent other than water, such as alcohols, ethers, glycols, glycol ethers, glycol polyethers, carboxylic acids, inorganic acids, organic nitrates, and any other compounds that contain either active or tautomeric hydrogen.
• Non-aqueous converting agents also include those agents that contain some water as a diluent or impurity.
• alcohols such as methanol or isopropyl alcohol or other low molecular weight (i.e. more volatile) alcohols, because of environmental concerns and restrictions related to venting gases during the grease manufacturing process or hazardous waste disposal of scrubbed alcohols.
• the total amount of water added as a converting agent, based on the final weight of the grease, is between 1.5% and 10%, preferably between 2.0% and 5.0%, most preferably between 2.2% and 4.5%. Additional water may be added after conversion. Also, if the conversion takes place in an open vessel at a sufficiently high temperature so as to volatilize a significant portion of the water during conversion, additional water may be added to replace the water that was lost.
• the total amount of one or more non-aqueous converting agents added, based on the final weight of the grease, is between 0.1% and 5%, preferably 0.3 % and 4%, most preferably 0.5% and 2.0%.
• the amount of non-aqueous converting agent used will decrease as the amount of overbased calcium sulfonate decreases.
• some or all of them may be removed by volatilization during the manufacturing process.
• the lower molecular weight glycols such as hexylene glycol and propylene glycol.
• some converting agents may also serve as complexing acids, to produce a calcium sulfonate complex grease according to one embodiment of the invention, discussed below. Such materials will simultaneously provide both functions of converting and complexing.
• a small amount of a facilitating acid may be added to the mixture prior to conversion according to another embodiment of the invention.
• Suitable facilitating acids such as an alkyl benzene sulfonic acid, having an alkyl chain length typically between 8 to 16 carbons, may help to facilitate efficient grease structure formation. Most preferably, this alkyl benzene sulfonic acid comprises a mixture of alkyl chain lengths that are mostly about 12 carbons in length.
• Such benzene sulfonic acids are typically referred to as dodecylbenzene sulfonic acid ("DDBSA").
• benzene sulfonic acids of this type include JemPak 1298 Sulfonic Acid as supplied by JemPak GK Inc., Calsoft LAS-99 as supplied by Pilot Chemical Company, and Biosoft S-101 as supplied by Stepan Chemical Company.
• the alkyl benzene sulfonic acid is used in the present invention, it is added before conversion in an amount from about 0.50% to 5.0%, preferably 1.0% to 4.0%, most preferably 1.3% to 3.6%, based on the final weight of the grease.
• the calcium sulfonate is made in situ using alkyl benzene sulfonic acid, the facilitating acid added according to this embodiment is in addition to that required to produce the calcium sulfonate.
• One or more complexing acids, one or more calcium containing bases, and one or more alkali metal hydroxides are also added as ingredients in a preferred embodiment of a calcium sulfonate grease composition according to the invention.
• the calcium containing bases may include calcium hydroxyapatite, added calcium carbonate, added calcium hydroxide, added calcium oxide, or a combination of one or more of the foregoing.
• the calcium hydroxyapatite used as a calcium containing base for reacting with complexing acids according to this embodiment may be added pre-conversion, post-conversion, or a portion added pre- and a portion added post-conversion.
• the calcium hydroxyapatite is finely divided with a mean particle size of around 1 to 20 microns, preferably around 1 to 10 microns, most preferably around 1 to 5 microns.
• the calcium hydroxyapatite will be of sufficient purity so as to have abrasive contaminants such as silica and alumina at a level low enough to not significantly impact the anti-wear properties of the resulting grease.
• the calcium hydroxyapatite should be either food grade or U.S. Pharmacopeia grade.
• the amount of calcium hydroxyapatite added will be between 1.0% and 20%, preferably 2% and 15%, most preferably 3% and 10%, based on the total weight of the grease, although more can be added, if desired, after conversion and all reaction with complexing acids is complete.
• calcium hydroxyapatite may be added to the above ingredients in an amount that is insufficient to fully react with the complexing acids.
• finely divided calcium carbonate as an oil-insoluble solid calcium-containing base may be added, preferably before conversion, in an amount sufficient to fully react with and neutralize the portion of any subsequently added complexing acids not neutralized by the calcium hydroxyapatite.
• calcium hydroxyapatite may be added to the above ingredients in an amount that is insufficient to fully react with the complexing acids.
• finely divided calcium hydroxide and/or calcium oxide as an oil-insoluble solid calcium-containing base may be added, preferably before conversion, in an amount sufficient to fully react with and neutralize the portion of any subsequently added complexing acids not neutralized by the co-added calcium hydroxyapatite.
• the calcium hydroxide and/or calcium oxide preferably represents no more than 75% of the hydroxide equivalent basicity provided by the total of the added calcium hydroxyapatite, calcium hydroxide, and calcium oxide.
• calcium carbonate may also be added with the calcium hydroxyapatite, calcium hydroxide and/or calcium oxide, with the calcium carbonate being added either before or after reacting with complexing acids.
• calcium carbonate is preferably added in an amount that is more than sufficient to neutralize any remaining complexing acid or acids.
• the added calcium carbonate used as a calcium containing base is finely divided with a mean particle size of around 1 to 20 microns, preferably around 1 to 10 microns, most preferably around 1 to 5 microns.
• the added calcium carbonate is preferably crystalline calcium carbonate (most preferably calcite) of sufficient purity so as to have abrasive contaminants such as silica and alumina at a level low enough to not significantly impact the anti-wear properties of the resulting grease.
• the calcium carbonate should be either food grade or U.S. Pharmacopeia grade.
• the amount of added calcium carbonate added is between 1.0% and 20%, preferably 2.0% and 15%, most preferably 3.0% and 10%, based on the final weight of the grease. These amounts are added as a separate ingredient in addition to the amount of dispersed calcium carbonate contained in the overbased calcium sulfonate.
• the added calcium carbonate is added prior to conversion as the sole added calcium-containing base ingredient for reacting with complexing acids. Additional calcium carbonate may be added to either the simple or complex grease embodiments of the invention after conversion, and after all reaction with complexing acids is complete in the case of a complex grease.
• references to added calcium carbonate herein refer to the calcium carbonate that is added prior to conversion and as one of or the sole added calcium-containing base for reaction with complexing acids when making a complex grease according to the invention.
• the added calcium hydroxide and/or added calcium oxide added pre-conversion or post-conversion shall be finely divided with a mean particle size of around 1 to 20 microns, preferably around 1 to 10 microns, most preferably around 1 to 5 microns.
• the calcium hydroxide and calcium oxide will be of sufficient purity so as to have abrasive contaminants such as silica and alumina at a level low enough to not significantly impact the anti-wear properties of the resulting grease.
• the calcium hydroxide and calcium oxide should be either food grade or U.S. Pharmacopeia grade.
• the total amount of calcium hydroxide and/or calcium oxide will be between 0.07% and 1.20%, preferably 0.15% and 1.00%, most preferably 0.18% and 0.80%, based on the total weight of the grease. These amounts are added as separate ingredients in addition to the amount of residual calcium hydroxide or calcium oxide contained in the overbased calcium sulfonate. Most preferably, an excess amount of calcium hydroxide relative to the total amount of complexing acids used is not added prior to conversion. According to yet another embodiment, it is not necessary to add any calcium hydroxide or calcium oxide for reacting with complexing acids and either added calcium carbonate or calcium hydroxyapatite may be used as the sole added calcium containing base for such reaction or may be used in combination for such reaction.
• the added alkali metal hydroxides comprise sodium hydroxide, lithium hydroxide, potassium hydroxide, or a combination thereof. Most preferably sodium hydroxide is used as the alkali metal hydroxide.
• the total amount of alkali metal hydroxide added is preferably around 0.005% to 0.5%, more preferably around 0.01% to 0.4%, and most preferably around 0.02% to 0.20%, by weight of the final grease product.
• the alkali metal hydroxide reacts with complexing acids resulting in an alkali metal salt of a complexing acid present in the final grease product.
• the preferred amounts indicated here are amounts added as raw ingredients relative to the weight of the final grease product, even though no alkali metal hydroxide will be present in the final grease.
• the alkali metal hydroxide is dissolved in the water prior to being added to other ingredients.
• the water used to dissolve the alkali metal hydroxide may be water used as a converting agent or water added post-conversion. It is most preferred to dissolve the alkali metal hydroxide in water prior to adding it to the other ingredients, but it may also be directly added to the other ingredients without first dissolving it in water.
• Complexing acids used in these embodiments will comprise at least one and preferably two or more of the following: long chain carboxylic acids, short chain carboxylic acids, boric acid, and phosphoric acid.
• Acetic acid and other carboxylic acids may be used as a converting agent or complexing acid or both, depending on when it is added.
• some complexing acids (such as the 12-hydroxystearic acid in the '514 and '467 patents) may be used as converting agents.
• the total amount of complexing acids added is preferably between 2.8% and 11% by weight of the final grease.
• the long chain carboxylic acids suitable for use in accordance with the invention comprise aliphatic carboxylic acids with at least 12 carbon atoms.
• the long chain carboxylic acids comprise aliphatic carboxylic acids with at least 16 carbon atoms.
• the long chain carboxylic acid is 12-hydroxystearic acid.
• the amount of long chain carboxylic acid is between 0.5% and 5.0%, preferably 1.0% to 4.0%, most preferably 2.0% to 3.0%, based on the final weight of the grease.
• Short chain carboxylic acids suitable for use in accordance with the invention comprise aliphatic carboxylic acids with no more than 8 carbon atoms, and preferably no more than 4 atoms. Most preferably, the short chain carboxylic acid is acetic acid. The amount of short chain carboxylic acids is between 0.05% and 2.0%, preferably 0.1% to 1.0%, most preferably 0.15% to 0.5%, based on the final weight of the grease. Any compound that can be expected to react with water or other components used in producing a grease in accordance with this invention with such reaction generating a long chain or short chain carboxylic acid are also suitable for use. For instance, using acetic anhydride would, by reaction with water present in the mixture, form the acetic acid to be used as a complexing acid.
• methyl 12-hydroxystearate would, by reaction with water present in the mixture, form the 12-hydroxystearic acid to be used as a complexing acid.
• additional water may be added to the mixture for reaction with such components to form the necessary complexing acid if sufficient water is not already present in the mixture.
• boric acid is used as a complexing acid according to this embodiment, an amount between 0.3% to about 4.0%, preferably 0.5% to 3.0%, and most preferably 0.6% and 2.0%, based on the final weight of the grease, is added.
• the boric acid may be added after first being dissolved or slurried in water, or it can be added without water. Preferably, the boric acid will be added during the manufacturing process such that water is still present.
• any of the well-known inorganic boric acid salts may be used instead of boric acid.
• any of the established borated organic compounds such as borated amines, borated amides, borated esters, borated alcohols, borated glycols, borated ethers, borated epoxides, borated ureas, borated carboxylic acids, borated sulfonic acids, borated epoxides, and borated peroxides may be used instead of boric acid.
• phosphoric acid is used as a complexing acid, an amount between 0.4% to 4.0%, preferably 0.6% and 3.0%, most preferably 0.8% and 2.0%, based on the final weight of the grease, is added.
• the percentages of various complexing acids described herein refer to pure, active compounds.
• any of these complexing acids are available in a diluted form, they may still be suitable for use in the present invention. However, the percentages of such diluted complexing acids will need to be adjusted so as to take into account the dilution factor and bring the actual active material into the specified percentage ranges.
• additives commonly recognized within the grease making art may also be added to either the simple grease embodiment or the complex grease embodiment of the invention.
• Such additives can include rust and corrosion inhibitors, metal deactivators, metal passivators, antioxidants, extreme pressure additives, antiwear additives, chelating agents, polymers, tackifiers, dyes, chemical markers, fragrance imparters, and evaporative solvents.
• the latter category can be particularly useful when making open gear lubricants and braided wire rope lubricants.
• the inclusion of any such additives is to be understood as still within the scope of the present invention. All percentages of ingredients are based on the final weight of the finished grease unless otherwise indicated, even though that amount of the ingredient may not be in the final grease product due to reaction or volatilization.
• the calcium sulfonate grease compositions are preferably made according to the methods of the invention described herein.
• the method comprises: (1) mixing overbased calcium sulfonate and a base oil; (2) dissolving an alkali metal hydroxide in water and adding and mixing the solution with the other ingredients; (3) adding and mixing one or more calcium containing bases; (4) adding and mixing one or more converting agents, which may include the water from step c if added prior to conversion; (5) adding and mixing one or more complexing acids; and (6) heating some combination of these ingredients until conversion has occurred.
• the method comprises these same steps, except that the converting agents comprise water and at least one non-aqueous converting agent and there is one or more delay periods between the pre-conversion addition of the water and the addition of at least a portion of the one or more other non-aqueous converting agents.
• alkali addition method will be used to describe all preferred embodiments of methods according to the invention where an alkali metal hydroxide is added without any delayed addition of non-aqueous converting agents and the term “alkali/delayed addition method” will be used to described all preferred embodiments of methods according to the invention where both an alkali metal hydroxide is added and there is at least one delay period between the addition of water as a converting agent and the addition of at least part of the non-aqueous converting agent(s).
• delayed addition method will be used to refer to the delayed non-aqueous converting agent method of the '476 application without any alkali metal hydroxide addition.
• each of the ingredients in steps (2), (3), and (5) can be added prior to conversion, after conversion, or a portion added prior and another portion added after conversion.
• a facilitating acid may also be added and mixed with the ingredients, preferably prior to conversion. If a facilitating acid is used, it is also preferable that it be added to the mixture before the alkali metal hydroxide is added.
• the alkali metal hydroxide may be added to the other ingredients without first dissolving in water, but it is most preferred to pre-dissolve it in water.
• the specific ingredients and amounts used in the method are according to the preferred embodiments of the composition described herein.
• the order of addition for the ingredients in steps (2), (3), and (5) relative to each other and to the ingredients in steps (1) and (4), and relative to the timing of heating the ingredients is not critical. However, the addition of some ingredients before or after other ingredients and/or before or after heating is preferred as described below. Additionally, the order of addition of converting agents is critical in the alkali/delayed addition method as described further below.
• a complex calcium sulfonate grease is produced by reacting and mixing certain compounds according to the steps outlined above, except that a first portion of water is added as a converting agent prior to conversion and a second portion of water is added after conversion and the alkali metal hydroxide is dissolved in the first portion of water or the second portion of water or both.
• water is added in at least two separate pre-conversion steps as a converting agent, with one or more temperature adjustment steps, addition of another ingredient(s) steps or a combination thereof between the first addition of water as a converting agent and the second addition of water as a converting agent and the alkali metal hydroxide is dissolved in the initial or first addition of water as a converting agent, or the second or subsequent addition of water as a converting agent, or both.
• both the alkali addition method and alkali/delayed addition method at least part of the complexing acids are added prior to heating. According to another preferred embodiment, all of the complexing acid(s) are added prior to heating. According to yet another preferred embodiment of both the alkali addition method and alkali/delayed addition method, when added calcium carbonate is used as the added calcium containing base for reacting with complexing acids, it added before any complexing acid(s). According to yet another preferred embodiment of both the alkali addition method and alkali/delayed addition method, calcium hydroxyapatite, added calcium hydroxide and added calcium carbonate are all used as calcium containing bases for reacting with complexing acids.
• the calcium hydroxyapatite and at least a portion of the calcium hydroxide prior to adding any complexing acids and add the calcium carbonate after at least part of the complexing acids are added, if complexing acids are added prior to conversion.
• the water with dissolved alkali metal hydroxide is added after the calcium containing base(s) are added and/or after a portion of the pre-conversion complexing acid(s) are added.
• the water with dissolved alkali metal hydroxide (or alkali metal hydroxide added separately) are added before adding a least a portion of one or more complexing acids.
• step (3) addition of calcium containing base(s) involves one of the following: (a) admixing finely divided calcium hydroxyapatite prior to conversion as the only calcium containing base added; (b) admixing finely divided calcium hydroxyapatite and calcium carbonate in an amount sufficient to fully react with and neutralize subsequently added complexing acids, according to one embodiment; (c) admixing finely divided calcium hydroxyapatite and calcium hydroxide and/or calcium oxide in an amount sufficient to fully react with and neutralize subsequently added complexing acids, with the calcium hydroxide and/or calcium oxide preferably being present in an amount not more than 75% of the hydroxide equivalent basicity provided by the total of the added calcium hydroxide and/or calcium oxide and the calcium hydroxyapatite, according to another embodiment of the invention; (d) admixing added calcium carbonate after conversion,
• the delay period there is at least one delay period between the pre-conversion addition of the water and the pre-conversion addition of at least a portion of the one or more other non-aqueous converting agents.
• a first delay period begins after the first addition of water as a converting agent. If additional water is added pre-conversion to make up for evaporation losses during the manufacturing process, those additions are not used in re-starting or determining delay periods, and only the first addition of water is used as the starting point in determining delay periods.
• one or more of the delay periods is a temperature adjustment delay period or a holding delay period or both.
• the delay periods may involve multiple temperature adjustment delay periods and multiple holding delay periods.
• a first temperature adjustment delay period is the period of time after water is added that it takes to change the temperature of the mixture (typically by heating) to a desired temperature or range of temperatures (the first temperature).
• a first holding delay period is the amount of time the mixture is held at the first temperature.
• a second temperature adjustment delay period is the period of time after the first holding delay that it takes to heat or cool the mixture to another temperature or temperature range (the second temperature).
• a second temperature adjustment delay period may also be the amount of time after a first temperature adjustment delay period to heat or cool the mixture to another temperature or range of temperatures (the second temperature) when another ingredient (such as a complexing acid) is added after reaching the first temperature, but there is no delay period between reaching that temperature and continuing to heat or cool to the second temperature.
• a second holding delay period is the amount of time the mixture is held at the second temperature. Additional temperature adjustment delay periods and holding delay periods (i.e. a third temperature adjustment delay period) follow the same pattern.
• the first temperature may be ambient temperature or an elevated temperature. Any subsequent temperature may be higher or lower than the previous temperature.
• the final pre-conversion temperature will be between about 88°C (190°F) and 104°C (220°F) or up to 110°C (230°F), as the temperature at which conversion in an open kettle typically occurs. Final pre-conversion temperatures can be below 88°C (190 F), however such process conditions will usually result in significantly longer conversion times, and thickener yields may also be diminished.
• the final pre-conversion temperature and temperature range at which conversion occurs may be different in a closed vessel. Any combination of temperature adjustment delay periods and/or holding delay periods may be used. Most preferably, the mixture of pre-conversion ingredients is heated to a temperature or temperature range during at least one of the delay periods or during each delay period.
• a holding delay period will be followed or preceded by a temperature adjustment delay period and vice versa, but there may be two holding delay periods back to back or two temperature adjustment periods back to back.
• the mixture may be held at ambient temperature for 30 minutes prior to adding one non-aqueous converting agent (a first holding delay period) and may continue to be held at ambient temperature for another hour prior to adding the same or a different non-aqueous converting agent (a second holding delay period).
• the mixture may be heated or cooled to a first temperature after which a non-aqueous converting agent is added (a first temperature adjustment period) and then the mixture is heated or cooled to a second temperature after which the same or a different non-aqueous converting agent is added (a second temperature adjustment period, without any interim holding period).
• a portion of a non-aqueous converting agent need not be added after every delay period, but may skip delay periods prior to addition or between additions.
• the mixture may be heated to a temperature (first temperature adjustment delay period) and then held at that temperature for a period of time (a first holding delay period) before adding any non-aqueous converting agent.
• a non-aqueous converting agent or portion thereof is added immediately after reaching a temperature or range of temperatures, then there is no holding delay period for that particular temperature and that portion of the non-aqueous converting agent; but if another portion is added after holding at that temperature or range of temperatures for a period of time then there is a holding time delay for that temperature and that portion of the non-aqueous converting agent.
• a portion of one or more non-aqueous converting agents may be added after any temperature adjustment delay period or holding delay period and another portion of the same or a different non-aqueous converting agent may be added after another temperature adjustment delay period or holding delay period.
• the duration of each temperature adjustment delay period will be about 30 minutes to 24 hours, or more typically about 30 minutes to 5 hours. However, the duration of any temperature adjustment delay period will vary depending on the size of the grease batch, the equipment used to mix and heat the batch, and the temperature differential between the starting temperature and final temperature, as will be understood by those of ordinary skill in the art.
• propylene glycol or hexylene glycol a portion of the glycol is added at substantially the same time as the water and another portion of glycol and all of any other non-aqueous converting agents are added after at least one delay period; (e) when acetic acid is added pre-conversion, it is added at substantially the same time as the water, and another (different) non-aqueous converting agent is added after a delay period; (f) at least a portion of one or more non-aqueous converting agents is added at the end of a final of the one or more delay periods and another portion of the same and/or a different non-aqueous converting agent is added after one or more prior delay periods; or (g) all of the one or more non-aqueous converting agents are added at the end of a final of the one or more delay periods.
• all or a portion of the non-aqueous converting agents are added in a batch manner (all at once, en masse, as opposed to a continuous addition over the course of a delay period, described below) after a delay period. It is noted, however, that in large or commercial scale operations, it will take some time to complete the batch addition of such non-aqueous converting agents to the grease batch because of the volume of materials involved. In batch addition, the amount of time it takes to add the non-aqueous converting agent to the grease mixture is not considered a delay period.
• any delay prior to the addition of that non-aqueous converting agent or portion thereof ends at the start time of the batch addition of the non-aqueous converting agent.
• at least one or a portion of one non-aqueous converting agent is added in a continuous manner during the course of a delay period (either a temperature adjustment delay period or a holding delay period).
• Such continuous addition may be by slowly adding the non-aqueous converting agent at a substantially steady flow rate or by repeated, discrete, incremental additions during a temperature adjustment delay period, a holding delay period, or both. In that case, the time it takes to fully add the non-aqueous converting agent is included in the delay period, which ends when the addition of non-aqueous converting agent is complete.
• At least a portion of one non-aqueous converting agent is added in a batch manner after a delay period and at least another portion of the same or a different non-aqueous converting agent is added in a continuous manner during a delay period.
• alcohols are not used as non-aqueous converting agents.
• a delay period within the scope of this invention may involve a holding delay period that does not involve heating (e.g. where the mixture was held at ambient temperature for a first holding delay period prior to heating), a short period of time of less than 15 minutes between the addition of water as a converting agent and the addition of all of the non-aqueous converting agent(s) without any heating during that time period is not a "delay" or "delay period” as used herein.
• a delay for the addition of any or all of the non-aqueous converting agent(s) without heating during the delay period should be at least about 20 minutes and more preferably at least about 30 minutes.
• An interval of less than 20 minutes between the addition of water and a portion of a non-aqueous converting agent, without heating during the 20 minutes, but with a subsequent longer holding delay period or subsequent heating prior to the addition of another portion of the same, or a portion or all of a different, non-aqueous converting agent(s) does involve a "delay period" within the scope of the invention.
• the initial short interval is not a "delay period”
• the subsequent longer holding delay or temperature adjustment delay prior to addition of a non-aqueous converting agent is a holding delay period or temperature adjustment delay period for purposes of this invention.
• non-aqueous converting agents may be slowly added during one or more temperature adjustment delay periods or holding delay periods or both. Such slow addition may include a substantially continuous addition of the non-aqueous converting agent during the delay period(s) or repeated, incremental additions during the delay period(s).
• acetic acid or 12-hydroxystearic acid when added pre-conversion, these acids acid will have a dual role as both converting agent and complexing acid.
• these acids When these acids are added along with another more active non-aqueous converting agent (such as a glycol), the acid may be considered to act primarily in the role of complexing acid, with the more active agent taking on the primary role of converting agent.
• acetic acid or 12-hydroxystearic acid is added pre-conversion along with a more active converting agent, any elapsed time between the addition of water and any portion of the acetic acid or 12-hydroxystearic acid is not considered a delay as that term is used herein.
• acetic acid or 12-hydroxystearic acid or a combination thereof is/are the only non-aqueous converting agent(s) used, then a temperature adjustment delay period or holding delay period between the pre-conversion addition of water and the pre-conversion addition of any portion of the acetic acid or 12-hydroxystearic acid would be a delay for purposes of this invention.
• One preferred embodiment of the alkali/delayed addition method according to the invention comprises steps of: (1) admixing in a suitable grease manufacturing vessel the following ingredients: water as a converting agent, a highly overbased oil-soluble calcium sulfonate containing dispersed amorphous calcium carbonate, optionally an appropriate amount of a suitable base oil (if needed), one or more alkali metal hydroxides, and optionally at least a portion of one or more non-aqueous converting agents to form a first mixture; (2) mixing or stirring the first mixture while maintaining it at a temperature or within a range of temperatures and/or adjusting the temperature of the first mixture to heat or cool it to another temperature(s) or range of temperatures during one or more delay periods; (3) optionally admixing at least a portion of one or more non-aqueous converting agents with the first mixture after or during one or more delay periods to form a second mixture; (4) heating the first mixture (or second mixture if non-aqueous converting agents are added in step 3) to a conversion
• Step (7) may be carried out prior to conversion or after conversion, or some portion or all of one or more calcium containing bases may be added prior to conversion and some portion or all of one or more calcium containing bases may be added after conversion.
• Step (8) may be carried out at any time prior to conversion.
• Step (9) may be carried out prior to conversion or after conversion, or some portion or all of one or more of the complexing acids may be added prior to conversion and some portion or all of one or more of the complexing acids added after conversion.
• this alkali/delayed addition method is carried out in an open vessel, but may also be carried out in a pressurized vessel.
• the one or more alkali metal hydroxides are dissolved in the water to be used as a converting agent prior to adding them in step (1).
• the alkali metal hydroxide may be omitted from step (1) and may be dissolved in water and the solution added at a later step prior to conversion or after conversion.
• any portion of a non-aqueous converting agent added in steps 1, 3, and/or 5 may be the same non-aqueous converting agent as that added in another step or steps or different from any non-aqueous converting agent added in another step or steps.
• a portion of at least one non-aqueous converting agent is added after a delay period (in step 3 or step 5)
• another portion of the same and/or at least a portion of a different non-aqueous converting agent or agents may be added in any combination of steps 1, 3, and/or 5.
• all of the one or more of the non-aqueous converting agents are admixed after the final delay period in step 5, with none being added during steps 1 or 3.
• at least a portion of one or more non-aqueous converting agents is added with the first mixture in step 1 prior to any delay and at least a portion of the same or a different non-aqueous converting agent is added in step 3 and/or in step 5.
• no non-aqueous converting agents are added with the first mixture and at least a portion of one or more non-aqueous converting agents is added is added in step 3 and in step 5.
• at least a portion of one or more non-aqueous converting agents is added after or during one delay period in step 3 and at least a portion of the same or a different non-aqueous converting agent is added after or during another delay period (a second delay period in step 3 and/or a final delay period in step 5).
• At least a portion of one or more non-aqueous converting agents is added after one or more delays in step 3, but no non-aqueous converting agents are added after the final delay period in step 5.
• steps (2)-(6) for making a complex grease are important aspects of the invention with respect to embodiments including the alkali/delayed addition method. Certain other aspects of the process are not critical to obtaining a preferred calcium sulfonate grease compositions according to the invention.
• the order that the calcium containing bases are added relative to each other is not critical.
• the temperature at which the water as a converting agent and calcium containing bases are added is not critical in order to obtain an acceptable grease, but it is preferred that they be added before the temperature reaches 88°C to 93°C (190 F to 200 F) (or other temperature range at which conversion occurs when made in a closed vessel).
• the order in which they are added either before or after conversion is also not generally critical.
• Another preferred embodiment of the alkali/delayed addition method comprises: mixing water, one or more alkali metal hydroxides, less than 45% overbased calcium sulfonate containing dispersed amorphous calcium carbonate, and optionally base oil to form a first mixture; adding at least a portion of one or more non-aqueous converting agents to the first mixture after or during one or more delay periods to form a pre-conversion mixture; converting the pre-conversion mixture to a converted mixture by heating until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to crystalline calcium carbonate has occurred, with at least one of the delay periods being a holding delay period where the first mixture or pre-conversion mixture is maintained at a temperature or within a range of temperatures for a period of time.
• the one or more alkali metal hydroxides are added after conversion instead of pre-conversion or a portion is added pre-conversion and a portion is added post-conversion.
• the pre-conversion and post-conversion additions may be of the same or a different alkali metal hydroxide.
• Another preferred embodiment of the alkali/delayed addition method comprises: mixing water, one or more alkali metal hydroxides, less than 36% overbased calcium sulfonate containing dispersed amorphous calcium carbonate, and optionally base oil to form a first mixture; adding at least a portion of one or more non-aqueous converting agents to the first mixture after or during one or more delay periods to form a pre-conversion mixture; converting the pre-conversion mixture to a converted mixture by heating until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to crystalline calcium carbonate has occurred.
• the one or more alkali metal hydroxides are added after conversion instead of pre-conversion or a portion is added pre-conversion and a portion is added post-conversion.
• the pre-conversion and post-conversion additions may be of the same or a different alkali metal hydroxide.
• Another preferred embodiment of the alkali/delayed addition method comprises the steps of: admixing in a suitable grease manufacturing vessel a highly overbased oil-soluble calcium sulfonate containing dispersed amorphous calcium carbonate and an amount of suitable base oil (if needed) and begin mixing. Then one or more facilitating acids are added and mixed, preferably for about 20-30 minutes. Then all of the calcium hydroxyapatite is added, followed by a portion of the calcium hydroxide, and then all of the calcium carbonate, which is mixed for another 20-30 minutes.
• acetic acid and a portion of the 12-hydroxystearic acid are added and mixed for another 20-30 minutes (it is noted that these ingredients may be converting agents, but since they are added before the water there is no delay period with respect to them).
• water used as a converting agent with a small amount of an alkali metal hydroxide having been dissolved in the water, is added and mixed while heating to a temperature between 88°C and 110°C (190°F and 230°F) (a first temperature adjustment delay period and the final delay period). Then all of the hexylene glycol is added as a non-aqueous converting agent.
• the mixture is converted by continuing to mix while maintaining the temperature in the conversion temperature range (preferably 88°C to 110°C (190 F to 230 F), for an open vessel) until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to very finely divided crystalline calcium carbonate is complete.
• the remaining calcium hydroxide is added and mixed for about 20-30 minutes.
• the remaining acetic acid and remaining 12-hydroxystearic acid are added and mixed for around 30 minutes.
• boric acid dispersed in water is added followed by the slow, gradual addition of phosphoric acid.
• the mixture is then heated to remove water and volatiles, cooled, more base oil is added as needed, and the grease is milled as described below. Additional additives may be added during the final heating or cooling steps.
• the steps and ingredients are the same as outlined above except that after adding the water as a converting agent and before adding all of the hexylene glycol as a non-aqueous converting agent, the mixture is heated to around 71°C (160°F) (a first temperature adjustment delay period) and held at that temperature for around 30 minutes (a first holding delay period) before continuing to heat to between 88°C and 110°C (190°F and 230°F) (a second temperature adjustment delay period and the final delay period).
• both the alkali addition method and the alkali/delayed addition method may occur in either an open or closed kettle as is commonly used for grease manufacturing.
• the conversion process can be achieved at normal atmospheric pressure or under pressure in a closed kettle. Manufacturing in open kettles (vessels not under pressure) is preferred since such grease manufacturing equipment is commonly available.
• an open vessel is any vessel with or without a top cover or hatch as long as any such top cover or hatch is not vapor-tight so that significant pressure cannot be generated during heating. Using such an open vessel with the top cover or hatch closed during the conversion process will help to retain the necessary level of water as a converting agent while generally allowing a conversion temperature at or even above the boiling point of water.
• both the alkali addition method and the alkali/delayed addition method of making a complex calcium sulfonate grease also includes the steps of: (a) mixing additional base oil and complexing acids, as needed after conversion; (b) mixing and heating to a temperature sufficiently high to insure removal of water and any volatile reaction byproducts and optimize final product quality; (c) cooling the grease while adding additional base oil as needed; (d) adding remaining desired additives as are well known in the art; and, if desired, (e) milling the final grease as required to obtain a final smooth homogenous product.
• the order and timing of these final steps is not critical, it is preferred that water be removed quickly after conversion.
• the grease is heated (preferably under open conditions, not under pressure, although pressure may be used) to between 121°C and 149°C (250 F and 300 F), preferably 149°C to 193°C (300 F to 380 F), most preferably 193°C to 204°C (380 F to 400 F), to remove the water that was initially added as a converting agent, as well as any water formed by chemical reactions during the formation of the grease. Having water in the grease batch for prolonged periods of time during manufacture may result in degradation of thickener yield, dropping point, or both, and such adverse effects may be avoided by removing the water quickly. If polymeric additives are added to the grease, they should preferably not be added until the grease temperature reaches 149°C (300 F).
• Polymeric additives can, if added in sufficient concentration, hinder the effective volatilization of water. Therefore, polymeric additives should preferably be added to the grease only after all water has been removed. If during manufacture it can be determined that all water has been removed before the temperature of the grease reaches the preferred 149°C (300 F) value, then any polymer additives may preferably be added at any time thereafter.
• overbased calcium sulfonate grease compositions and methods for making such compositions according to the invention are further described and explained in relation to the following examples:
• Example 1A (Baseline Example - No Alkali Addition Method, No Alkali/delayed addition method): A calcium sulfonate complex grease according to the composition of the ⁇ 768 application was made as follows: 264.61 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 327.55 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F), and 11.70 grams of PAO having a viscosity of 4 cSt at 100 C.
• the 400 TBN overbased oil-soluble calcium sulfonate was a poor quality calcium sulfonate similar to the one previously described and used in Examples 10 and 11 of the ⁇ 768 application.
• Mixing without heat began using a planetary mixing paddle. Then 23.94 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.65 grams of calcium hydroxyapatite with a mean particle size of around 1 to 5 microns, and 3.63 grams of food grade purity calcium hydroxide having a mean particle size of around 1 to 5 microns were added and allowed to mix in for 30 minutes.
• the amount of calcium hydroxide added as a separate ingredient is in addition to the amount of residual calcium hydroxide contained within the overbased calcium sulfonate. Then 0.88 grams of glacial acetic acid and 10.53 grams of 12-hydroxystearic acid were added and allowed to mix in for 10 minutes. Then 55.03 grams of finely divided calcium carbonate with a mean particle size around 1 to 5 microns were added and allowed to mix in for 5 minutes. The amount of calcium carbonate added as a separate ingredient is in addition to the amount of dispersed calcium carbonate contained within the overbased calcium sulfonate. Then 13.20 grams of hexylene glycol (a non-aqueous converting agent) and 38.22 grams water were added at the substantially the same time (no delay period).
• the mixture was heated until the temperature reached 88°C (190 F). The temperature was held between 88°C and 93°C (190 F and 200 F) for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that the conversion of the amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred.
• FTIR Fourier Transform Infrared
• Example 1B (Delayed Addition Method of '476 Application, No Alkali Addition): Another calcium complex grease using the same equipment, raw materials, amounts, and manufacturing process as the Example 1A grease was made, except that there was a delay in adding the non-aqueous converting agent (hexylene glycol).
• the other initial ingredients including water
• the other initial ingredients were mixed and heated to a temperature of about 88°C (190°F) (a first temperature adjustment delay period) and the hexylene glycol was added immediately upon reaching 88°C (190°F) (no holding delay period).
• a first temperature adjustment delay period a first temperature adjustment delay period
• hexylene glycol was added immediately upon reaching 88°C (190°F) (no holding delay period).
• the grease was held at 88 - 93°C (190 F - 200 F) for an additional 45 minutes.
• Example 1 The final grease had a worked 60 stroke penetration of 290.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 21.4%.
• the dropping point was > 343°C (650 F).
• the grease of this example had an improved thickener yield compared to the grease of the previous Example 1 as evidenced by the lower final percentage of overbased calcium sulfonate as compared to the worked penetration.
• Example 2 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made similar to the Example 1B grease, including delayed addition of the non-aqueous converting agent, except that an alkali metal hydroxide was also added to the water.
• the grease was made as follows: 240.35 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 345.33 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F), and 10.79 grams of PAO having a viscosity of 4 cSt at 100 C..
• the 400 TBN overbased oil-soluble calcium sulfonate was a poor quality calcium sulfonate similar to the one previously described and used in Examples 10 and 11 of U.S. Patent Application 13/664,768 .
• Mixing without heat began using a planetary mixing paddle. Then 21.81 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• the mixture was heated to about 82°C (180 F). Then 0.76 grams of glacial acetic acid (primarily as a complexing acid, since glycol is added later as a non-aqueous converting agent) and 9.63 grams of 12-hydroxystearic acid were added. It is noted that 12-hydroxystearic acid will quickly melt, dissolve, and react at a temperature of around 82°C (180 F) at which it was added. Shortly after adding the two complexing acids the mixture began to develop an appearance of whipped cream. This appearance does not typically occur when the added water does not contain a small amount of alkali metal hydroxide, and it is likely somehow related to the more rapid formation of the calcium salts of the complexing acids.
• whipped cream appearance is that as the sodium fatty acid salt is first formed, a small steady state concentration is maintained until all the calcium fatty acid salts have formed.
• Sodium fatty acid salts are well-known to be surface active with water and can cause foaming, which may result in the whipped cream appearance.
• the mixture was stirred while continuing to heat to a temperature of 88°C to 93°C (190 F to 200 F) (a first temperature adjustment delay period).
• a temperature of 88°C to 93°C 190 F to 200 F
• the whipped cream appearance subsided.
• 12.46 grams of hexylene glycol were added as the non-aqueous converting agent. After an hour and 10 minutes visible conversion had not yet occurred.
• An FTIR also indicated that most of the initially added water had been lost due to evaporation. An additional 35 ml of water and another 12.47 grams of hexylene glycol were added. After another one hour and 20 minutes, visible conversion occurred.
• the grease was further heated to a target temperature of 199°C (390 F). However, the top temperature was overshot to a value of 221°C (429 F). The heating mantle was removed and the grease was allowed to cool by continuing to stir in open air. The polymer was melted and fully dissolved in the grease mixture when the maximum temperature had been reached.
• 149°C 300 F
• 30.29 grams of food grade anhydrous calcium sulfate having a mean particle size below 5 microns were added.
• the temperature of the grease cooled to 93°C (200 F) 2.23 grams of an aryl amine antioxidant and 4.18 grams of a polyisobutylene polymer were added. An additional 49.92 grams of the same paraffinic base oil were added.
• this example grease would have had a percent overbased calcium sulfonate concentration of 19.85% if additional base oil had been added to bring the worked penetration to the same value as the previous Example 1B grease. This result is even more remarkable since this Example 2 grease was overheated by about 29 F, an effect known to have a potentially deleterious effect on thickener yield.
• the amount of sodium hydroxide based on its initial, unreacted weight in the final grease product was 0.06%.
• references to the percentage of alkali metal hydroxide in final greases of the invention refer to the amount of alkali metal hydroxide added as an ingredient in making the grease, since the alkali metal hydroxide will react with complexing acids to form a salt and will not be present as the initial, unreacted hydroxide in the final grease.
• its concentration in the final greases are expressed in terms of the amount of alkali metal hydroxide added as an ingredient relative to the weight of the final grease product.
• Example 3 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 2 grease. The only significant difference was that the initial portions of complexing acids acetic acid and 12-hydroxystearic acid were added at the beginning of the process while the mixture was still at ambient laboratory temperature (prior to any heating). Like the previous Example 2 grease, this grease used an embodiment of the alkali/delayed addition method. Additionally, care was taken to insure that the batch was not overheated during the final heating step.
• the grease of Example 3 was made as follows: 240.31 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 345.09 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F), and 10.03 grams of PAO having a viscosity of 4 cSt at 100 C.
• the 400 TBN overbased oil-soluble calcium sulfonate was a poor quality calcium sulfonate similar to the one previously described and used Examples 10 and 11 of U.S. Patent Application 13/664,768 . Mixing without heat began using a planetary mixing paddle.
• the mixture was heated until the temperature reached 88°C to 93°C (190 F to 200 F) (a first temperature adjustment delay period). During the heating to this temperature range, an appearance of whipped cream became evident when the temperature reached about 66°C (150 F). The whipped cream appearance subsided shortly after reaching the 88°C to 93°C (190 to 200 F) temperature range. Upon reaching the 88°C to 93°C (190 - 200 F) temperature range, 24.17 grams of hexylene glycol were added (no holding delay period). This amount corresponds to about the total amount of hexylene glycol that was added in the two separate portions in the previous example grease.
• Example 3 The final grease in Example 3 had a worked 60 stroke penetration of 282.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 19.20%.
• the dropping point was > 343°C (650 F).
• this grease had an improved thickener yield compared to the greases of Examples 1A and 1B.
• this grease had an improved yield compared to every example grease in the '473 application, the ⁇ 768 application, and U.S. Patent No. 9,273,265 .
• Example 4 (Baseline Example -No Alkali Metal Hydroxide, No Delay Period): Another calcium sulfonate complex grease was made in like manner with the previous example greases, except that a different base oil was used, a different non-aqueous converting agent was used, boric acid was not used, no alkali metal hydroxide was added, and there was no delay period between the addition of water and the non-aqueous converting agent.
• This example grease serves as a baseline for comparison with other example greases described herein where an alkali metal hydroxide was added and there was at least one delay period between the addition of water and a non-aqueous converting agent.
• the grease of Example 4 was made as follows: 297.25 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 373.60 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined in the ⁇ 768 application. Mixing without heat began using a planetary mixing paddle. Then 26.99 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• FTIR Fourier Transform Infrared
• Example 5 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 4 grease, except that an alkali metal hydroxide was added and there was a delay between the addition of water and the non-aqueous converting agent.
• the alkali metal hydroxide used was sodium hydroxide, and its concentration in the final grease was 0.03%. Also, the amount of non-aqueous converting agent (propylene glycol) was approximately doubled compared to the previous Example 4 grease, in accordance with what was observed in the earlier Examples 2 and 3 greases where embodiments of the alkali/delayed addition method were used.
• the grease in Example 5 was made as follows: 298.15 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 360.45 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined by the ⁇ 768 application. Mixing without heat began using a planetary mixing paddle. Then 27.10 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• FTIR Fourier Transform Infrared
• the percent overbased oil-soluble calcium sulfonate in the final grease was 21.78%.
• the dropping point was > 343°C (650 F).
• the thickener yield of this grease was much improved compared to the previous Example 4 grease, demonstrating again the remarkable effect of an embodiment of the alkali/delayed addition method.
• Example 6 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 5 grease, except that the amount of sodium hydroxide was doubled. The sodium hydroxide concentration in the final grease was 0.06%. The grease was made as follows: 297.40 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 360.93 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined by the ⁇ 768 application.
• Mixing without heat began using a planetary mixing paddle. Then 27.13 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.63 grams of calcium hydroxyapatite with a mean particle size below 5 microns and 4.20 grams of food grade purity calcium hydroxide having a mean particle size below 5 microns were added and allowed to mix in for 30 minutes.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 20.78%.
• the dropping point was >343°C (650 F).
• the thickener yield of this grease was much improved compared to the previous Example 4 grease, demonstrating yet again the remarkable effect of an embodiment of the alkali/delayed addition method.
• this example grease would have had a percent overbased calcium sulfonate concentration of 21.3% if base oil had been withheld to bring the worked penetration to the same value as the previous Example 5 grease. Therefore, it appears that doubling the amount of sodium hydroxide in this Example 6 grease imparted, at best, a minor further improvement on thickener yield when compared to the previous Example 5 grease.
• Example 7 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 6 grease. The only significant difference between this grease and the previous Example 6 grease was that this grease was held at 71 °C to 77°C (160 to 170 F) for one hour during the initial heating period.
• the grease was made as follows: 297.79 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 362.02 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined by the ⁇ 768 application.
• Mixing without heat began using a planetary mixing paddle. Then 27.01 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.64 grams of calcium hydroxyapatite with a mean particle size below 5 microns and 4.14 grams of food grade purity calcium hydroxide having a mean particle size below 5 microns were added and allowed to mix in for 30 minutes.
• this Example 7 grease would have had a percent overbased calcium sulfonate concentration of 25.76% if less base oil had been added so as to bring the worked penetration to the same value as the previous Example 4 grease where there was no alkali metal hydroxide added and no delay period.
• a first holding delay period at a first temperature range of 71°C to 77°C (160 to 170 F) prior to heating to 190 to 200.
• Example 12 and 17 of the ⁇ 476 application having a first holding delay period at a first temperature range of 71°C to 77°C (160 to 170 F) prior to heating to 88°C to 93°C (190 to 200 F) was shown to improve thickener yield (20.36% and 20.59%, respectively) when there was no alkali metal hydroxide added, although the first holding delay period in those examples was 2.5 hours.
• Example 8 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 6 grease, except that lithium hydroxide monohydrate was used as the added alkali metal hydroxide instead of sodium hydroxide. The lithium hydroxide concentration based on the monohydrate form in the final grease was 0.06%.
• the grease was made as follows: 298.61 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 362.54 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined by the ⁇ 768 application.
• Mixing without heat began using a planetary mixing paddle. Then 27.03 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.62 grams of calcium hydroxyapatite with a mean particle size below 5 microns and 4.11 grams of food grade purity calcium hydroxide having a mean particle size below 5 microns were added and allowed to mix in for 30 minutes.
• the heating mantle was removed and the grease was allowed to cool by continuing to stir in open air.
• the grease cooled to 149°C (300 F)
• the temperature of the grease cooled to 93°C (200 F)
• 5.78 grams of a mixture of aryl amine and high molecular weight phenolic antioxidants and 6.10 grams of an amine phosphate antioxidant/anti-rust additive were added. Two more portions of the same base oil totaling 112.37 grams were added. Mixing continued until the grease reached a temperature of 77°C (170 F).
• the grease was then removed from the mixer and given three passes through a three-roll mill to achieve a final smooth homogenous texture.
• the grease had a worked 60 stroke penetration of 295.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 21.79%.
• the dropping point was >343°C (650 F).
• the thickener yield of this grease was much improved compared to the previous Example 4 grease, demonstrating yet again the remarkable effect of utilizing an embodiment of the alkali/delayed addition method.
• the thickener yield improving effect of lithium hydroxide is not quite as effective as sodium hydroxide.
• Example 9 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 6 grease, except that potassium hydroxide was used as the added alkali metal hydroxide instead of sodium hydroxide.
• the potassium hydroxide was introduced in the form of a 47.9% solution in water. The amount of this solution added was adjusted so as to compensate both for the concentration of potassium hydroxide and also for the difference in molecular weights between sodium and potassium hydroxide. This was done so as to provide approximately the same molar amount of added hydroxide in this grease as in the Example 6 grease.
• the potassium hydroxide concentration in the final grease was 0.20%.
• the grease was made as follows: 302.52 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 357.60 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined by the ⁇ 768 application. Mixing without heat began using a planetary mixing paddle. Then 27.04 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• the mixture was heated with continued mixing until the temperature reached 88°C to 93°C (190 to 200 F). It was noted that when the temperature had reached about 77°C to 82°C (170 to 180 F), a whipped cream appearance had developed. Heating continued until the grease reached 93°C (200 F) (a first temperature adjustment delay period), and then 15 ml water and 29.72 grams of propylene glycol were added (no holding delay period). It was also observed at that time that the whipped cream appearance had subsided. Once visible conversion and thickening began, 65.89 grams of the same base oil and 10 ml water were added. As thickening continued, 36.32 grams of the same base oil and 10 ml water were added. This was followed by another 51.67 grams of the same base oil.
• the mixture was then heated with an electric heating mantle while continuing to stir.
• 149°C 300 F
• 2.75 grams of a styrene-alkylene copolymer were added as a crumb-formed solid.
• the grease was further heated to about 199°C (390 F) at which time all the polymer was melted and fully dissolved in the grease mixture.
• the heating mantle was removed and the grease was allowed to cool by continuing to stir in open air.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 23.03%.
• the dropping point was >343°C (650 F).
• the thickener yield of this grease was much improved compared to the previous Example 4 grease, demonstrating yet again the remarkable effect of utilizing an embodiment of the alkali/delayed addition method.
• the yield improving effect of potassium hydroxide is not quite as effective as either sodium hydroxide or lithium hydroxide.
• Example 10 (Embodiment of Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made in like manner with the previous Example 6 grease, except that more base oil was added initially, and the amounts of the overbased calcium sulfonate, C12 alkylbenzene sulfonic acid, propylene glycol converting agent, 12-hydroxystearic acid, and acetic acid were proportionally reduced compared to the amounts of added calcium hydroxide, calcium hydroxyapatite, added calcium carbonate, and phosphoric acid.
• the grease was made as follows: 233.60 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 422.48 grams of a USP purity white paraffinic mineral base oil having a viscosity of about 352 SUS at 38°C (100 F).
• the overbased calcium sulfonate was an NSF HX-1 food-grade approved overbased calcium sulfonate suitable for making NSF H-1 approved food grade greases and was of good quality as defined by the ⁇ 768 application. Mixing without heat began using a planetary mixing paddle. Then 21.04 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• the grease was then heated with an electric heating mantle while continuing to stir.
• 149°C (300 F) 2.79 grams of a styrene-alkylene copolymer were added as a crumb-formed solid.
• the grease was further heated to about 199°C (390 F) at which time all the polymer was melted and fully dissolved in the grease mixture.
• the heating mantle was removed and the grease was allowed to cool by continuing to stir in open air.
• 33.15 grams of food grade anhydrous calcium sulfate having a mean particle size below 5 microns were added.
• Example 11 (Baseline Example - No Alkali Metal Hydroxide Added, No Delay Period): Another calcium sulfonate complex grease was made similar to an embodiment of U.S. Patent 4,560,489 (issued to Witco Corporation on December 24, 1985 ), and as described in Example 18 of the ⁇ 476 application. As disclosed in the ⁇ 489 Patent, the sole calcium containing base added for reaction with complexing acids in this grease was calcium hydroxide. This grease serves as a baseline for the next two examples.
• the grease of Example 11 was made as follows: 440.02 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 390.68 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application. Then 17.76 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• This calcium hydroxide was the sole added calcium containing base for reaction with complexing acids. Then 28.59 grams 12-hydroxystearic acid were added and allowed to melt and react. Then 25.33 grams boric acid was mixed with 50 ml hot water, and the mixture was added to the grease. The grease was then heated to 166°C (330 F). The heating mantle was then removed and the grease was allowed to cool by continuing to stir in open air. When the grease cooled to 77°C (170 F), it was removed from the mixer and given three passes through a three-roll mill to achieve a final smooth homogenous texture. The grease had a worked 60 stroke penetration of 291. The percent overbased oil-soluble calcium sulfonate in the final grease was 46.92%. The Dropping point was >343°C (650 F).
• Example 12 (Embodiment of Alkali/Delayed Addition Method): Another grease was made in like manner with the previous grease, except that this grease had the non-aqueous converting agent hexylene glycol delayed in its addition until the mixture had been heated to 88°C to 93°C (190 to 200 F). Additionally, this grease had a small amount of sodium hydroxide dissolved in the second portion of water added at 88°C to 93°C (190 to 200 F) after the initial conversion had occurred, but before the calcium hydroxide, 12-hydroxystearic acid, or acetic acid was added. The sodium hydroxide concentration in the final grease was 0.08%.
• the grease was made as follows: 430.36 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 386.79 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application. Then 17.64 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• the grease was then heated to 390 to 400 F. The heating mantle was then removed and the grease was allowed to cool by continuing to stir in open air. When the grease was cooled to 93°C (200 F), 2.40 grams of an aryl amine antioxidant were added. Then two more portions of the same base oil totaling 165.54 grams were added and allowed to mix into the grease. When the grease cooled to 77°C (170 F), it was removed from the mixer and given three passes through a three-roll mill to achieve a final smooth homogenous texture. The grease had a worked 60 stroke penetration of 290. The percent overbased oil-soluble calcium sulfonate in the final grease was 39.38%. The Dropping point was >343°C (650 F). As can be seen, this grease had essentially the same worked penetration as the previous Example 11 grease. However, the thickener yield was significantly improved as indicated by the much lower percentage of overbased calcium sulfonate in this grease compared to the previous Example 11 grease.
• Example 13 (Embodiment of Alkali/Delayed Addition Method): Another grease was made in like manner with the previous grease in that the non-aqueous converting agent hexylene glycol was delayed in its addition until the mixture had been heated to 88°C to 93°C (190 to 200 F) (a first temperature adjustment delay period). However, in this grease the small amount of sodium hydroxide was dissolved in the initial portion of water added at ambient temperature before heating of the batch began. Once again, the sodium hydroxide concentration in the final grease was 0.08%.
• the grease was made as follows: 440.24 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 385.62 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application. Then 17.61 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 44.48 grams water into which 0.88 grams of powdered sodium hydroxide were dissolved were added.
• FTIR Fourier Transform Infrared
• Example 13 shows that the utilizing an embodiment of the alkali/delayed addition method provides very significant thickener yield improvement when using only calcium hydroxide for reaction with complexing acids (as opposed to the addition of calcium hydroxyapatite and/or added calcium carbonate in the previous examples and as disclosed in the ⁇ 768 application).
• both examples 12 and 13 show significant improvement in thickener yield compared to Example 11 where no alkali metal hydroxide was added.
• Example 12 and 13 greases both utilizing embodiments of the alkali/delayed addition method
• concentration of the non-aqueous converting agent in the Example 12 and 13 greases was the same as the Example 11 baseline grease. It appears that when using the prior art calcium sulfonate grease technology disclosed in the ⁇ 489 Patent with calcium hydroxide as the sole added calcium containing base, in combination with an embodiment of the alkali/delayed addition method, it is not necessary to increase the amount of non-aqueous converting agents to achieve a useful grease with improved thickener yield.
• Example 14 (Baseline Example, No Alkali Metal Addition and No Delay Period): A calcium sulfonate complex grease was made according to the composition and method disclosed in U.S. Patent No. 9,273,265 , wherein added calcium carbonate is a separately added ingredient in the grease. This grease did not include the addition of an alkali metal hydroxide or any delay period. This grease along with the next example grease serves as a baseline for comparison. The grease was made as follows: 310.25 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 368.14 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F).
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application.
• Mixing without heat began using a planetary mixing paddle. Then 31.31 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 75.03 grams of finely divided crystalline calcium carbonate with a mean particle size below 5 microns were added and allowed to mix in for 20 minutes. This calcium carbonate was added in addition to the amount of amorphous calcium carbonate contained in the overbased calcium sulfonate. Then 0.85 grams of glacial acetic acid and 8.09 grams of 12-hydroxystearic acid were added.
• the mixture was stirred for 10 minutes. Then 15.83 grams of hexylene glycol and 40.1 grams water were added (without any delay period), and the mixture was heated with continued mixing to a temperature of 88°C to 93°C (190 F to 200 F). During the heating step, it was noted that the mixture visibly converted to a grease structure at about 71 °C (160 F). Once the grease had reached 88°C to 93°C (190 to 200 F), Fourier Transform Infrared (FTIR) spectroscopy indicated that most of the water had been lost due to evaporation. Another 20 ml water was added.
• FTIR Fourier Transform Infrared
• FTIR Fourier Transform Infrared
• Example 15 (Baseline Example, No Alkali Metal Hydroxide added, No Delay period): Another calcium sulfonate complex grease was made in the same manner and according to the same composition as the previous Example 14 grease. This Example 15 grease and the previous Example 14 grease provide a baseline for comparison for the next two greases. The grease was made as follows: 310.19 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 367.82 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F).
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768. Mixing without heat began using a planetary mixing paddle. Then 31.28 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 75.31 grams of finely divided crystalline calcium carbonate with a mean particle size below 5 microns were added and allowed to mix in for 20 minutes. This calcium carbonate was added in addition to the amount of amorphous calcium carbonate contained in the overbased calcium sulfonate. Then 0.84 grams of glacial acetic acid and 8.10 grams of 12-hydroxystearic acid were added.
• the mixture was stirred for 10 minutes. Then 15.73 grams of hexylene glycol and 41.2 grams water were added, and the mixture was heated with continued mixing to a temperature of 88°C to 93°C (190 F to 200 F). During the heating step, it was noted that the mixture visibly converted to a grease structure at about 77°C (170 F). Once the grease had reached 88°C to 93°C (190 to 200 F), Fourier Transform Infrared (FTIR) spectroscopy indicated that most of the water had been lost due to evaporation. Another 20 ml water was added.
• FTIR Fourier Transform Infrared
• FTIR Fourier Transform Infrared
• Example 16 Another calcium sulfonate complex grease was made similar to the previous two greases. However, the non-aqueous converting agent hexylene glycol was not added initially with the water. Instead it was added after the mixture had been heated to 88°C to 93°C (190 to 200 F) (a first temperature adjustment delay period) and held at that temperature range for one hour (a first holding delay period). No alkali metal hydroxide was added to this grease. The grease was made as follows: 310.27 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 368.06 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F).
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application.
• Mixing without heat began using a planetary mixing paddle. Then 31.18 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 75.29 grams of finely divided crystalline calcium carbonate with a mean particle size below 5 microns were added and allowed to mix in for 20 minutes. This calcium carbonate was added in addition to the amount of amorphous calcium carbonate contained in the overbased calcium sulfonate. Then 0.85 grams of glacial acetic acid and 8.11 grams of 12-hydroxystearic acid were added.
• the mixture was stirred for 10 minutes. Then 41.2 grams water was added as a converting agent, and the mixture was heated with continued mixing to a temperature of 88°C to 93°C (190 F to 200 F) (a first temperature adjustment delay period). The mixture was mixed at this temperature range for one hour (a first holding delay period). During that time, Fourier Transform Infrared (FTIR) spectroscopy indicated that water was being lost due to evaporation. Another 30 ml water was added.
• FTIR Fourier Transform Infrared
• Example 17 (Embodiment of the Alkali/Delayed Addition Method): Another calcium sulfonate complex grease was made similar to the previous Example 16. However, this grease used an embodiment of the alkali/delayed addition method. The non-aqueous converting agent hexylene glycol was not added initially with the water, but was added after the mixture had been heated to 88°C to 93°C (190 to 200 F) (a first temperature adjustment delay period). Also, the initially added water contained a very small amount of sodium hydroxide. The sodium hydroxide concentration in the final grease was 0.08%. It should be noted that the batch size of this grease was increased by 50% compared to the Examples 14 - 16 greases. However, the percentages of each component and other process step details were not significantly different.
• the grease was made as follows: 465.31 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 367.68 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F).
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768. Mixing without heat began using a planetary mixing paddle. Then 46.64 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• this example grease would have had a percent overbased calcium sulfonate concentration of 30.52% if additional base oil had been added to bring the worked penetration to the same value as the previous Example 16 grease.
• the use of an embodiment of the alkali/delayed addition method in this grease did provide some improvement in thickener yield when compared to the two baseline greases of Examples 14 and 15. Nonetheless, the amount of improvement is not as significant as what was observed in some of the other example greases. Without being bound by theory, the lower amount of yield improvement provided by this grease may be due to the fact that there was no added calcium hydroxide.
• Example 18 (Baseline Example - No Alkali Metal Hydroxide Added, No Delay Period): A calcium sulfonate complex grease was made according to the scope of U.S. Patents 5,308,514 and 5,338,467 (issued to Witco Corporation on May 3, 1994 and August 16, 1994, respectively), where at least a portion of the long chain fatty acid is added prior to conversion and may act as a converting agent and where only calcium hydroxide or calcium oxide is added as a calcium containing base for reacting with complexing acids (no calcium hydroxyapatite or added calcium carbonate, as in the ⁇ 768 application).
• Example 6A This example is the same as Example 6A from the ⁇ 476 application, where 54.1% of the total amount of 12-hydroxystearic acid and all of the glacial acetic acid were added before conversion. The remaining amount of 12-hydroxystearic acid was added after conversion followed by calcium hydroxide and a boric acid water mixture. Additionally, no alkali metal hydroxide was added and there was no delay between the addition of water and the primary non-aqueous converting agent. This grease serves as a base line for comparison.
• the grease of Example 18 was made as follows: 380.73 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 604.50 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application. Then 21.66 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• Example 19 (Delayed Addition Method of ⁇ 476 Application, No Alkali Metal Hydroxide Added): Another calcium complex grease was made using the same equipment, raw materials, amounts, and manufacturing process as the Example 18 grease, except there was a first temperature adjustment delay period (heating to 88-93 (190-200)) and a first holding delay period (holding at 88-93 (190-200) for one hour) between the addition of water and hexylene glycol as the non-aqueous converting agent. No alkali metal hydroxide was added. When the hexylene glycol was added, the grease was held at 88°C to 93°C (190 F to 200 F) until conversion appeared to be complete. Then the remaining process was the same as the previous Example 18 grease.
• the final grease had a worked 60 stroke penetration of 281.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 27.60%.
• the dropping point was >343°C (650 F).
• the grease of this example had an improved thickener yield compared to the grease of the previous Example 18 as evidenced by the much firmer penetration despite having essentially the same percentage overbased oil-soluble calcium sulfonate.
• the predicted percentage of overbased calcium sulfonate in the Example 19 grease would be 24.2% if it was diluted with sufficient base oil to obtain the same worked penetration of the Example 18 grease.
• Example 20 (Embodiment of Alkali/Delayed Addition Method): Another grease was made in like manner with the previous Example 19 grease in that the non-aqueous converting agent hexylene glycol was delayed in its addition until the mixture had been heated to 88°C to 93°C (190 to 200 F). However, in this grease a small amount of sodium hydroxide was dissolved in the initial portion of water added at ambient temperature before heating of the batch began. Also, there was no one hour holding delay period once the 88°C to 93°C (190 to 200 F) temperature range had been reached. Instead, the hexylene glycol was added as soon as that temperature range was achieved. This was done in accordance to what was observed in the previous Example 7 grease where it was observed that a holding temperature delay for the non-aqueous converting agent did not provide the highest thickener yield improvement when an alkali metal hydroxide was also added.
• the grease was made as follows: 380.79 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 589.33 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application). Then 21.63 grams of a primarily C12 alkylbenzene sulfonic acid were added.
• FTIR Fourier Transform Infrared
• Example 21 (Embodiment of Alkali/Delayed Addition Method): Another grease was made nearly identical to the previous Example 20 grease. The only significant difference was that after conversion was complete, the mixture of sodium hydroxide in water was added. Then the second portion of 12-hydroxystearic acid and the mixture of boric acid in hot water were added. The final grease had a worked 60 stroke penetration of 285. The dropping point was >343°C (650 F). The percent overbased oil-soluble calcium sulfonate in the final grease was 27.40%. The concentration of sodium hydroxide in the final grease was 0.06%. As can be seen, the thickener yield of the Examples 19, 20, and 21 greases were all significantly superior to the Example 18 baseline grease.
• Example 22 (Baseline Example - No Alkali Metal Hydroxide Added, No Delay Period)
• a simple calcium sulfonate grease was made according to the scope of U.S. Patents 3,377,283 and 3,492,231 (issued to Lubrizol Corporation on April 9, 1968 and January 27, 1970, respectively), without any delay or alkali metal hydroxide addition for use as a baseline for comparison for the next three greases.
• the grease was made as follows: 496.49 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 394.45 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F).
• Example 23 (Delayed Addition Method of ⁇ 476 Application, No Alkali Addition) Another simple calcium sulfonate grease was made in like manner with the previous Example 22 grease, except that there delay periods between the addition of water and the non-aqueous converting agent. No alkali metal hydroxide was added in this example.
• the grease was made as follows: 495.41 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 391.96 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application). Then 19.65 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 44.42 grams of water was added. Then the mixture was heated to 71°C (160 F) (a first temperature adjustment delay period) and held between 71 °C and 77°C (160 F and 170 F) for two hours and 30 minutes (a first holding delay period). During this time, an additional 50 ml of water were added since most of the originally added water had evaporated. The batch was then heated to 190 F (a second temperature adjustment delay period), and 16.53 grams of hexylene glycol (the primary converting agent) followed by 6.34 grams of glacial acetic acid were added.
• Example 21 When the grease cooled to 77°C (170 F), it was removed from the mixer and given three passes through a three-roll mill to achieve a final smooth homogenous texture.
• the dropping point of the Example 21 grease was >343°C (650 F).
• the grease had a worked 60 stroke penetration of 290.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 53.14%.
• Example 24 (Alkali Addition and Delayed Addition) Another simple calcium sulfonate grease was made in like manner with the previous Example 23 grease, except that a different delay period was used between the addition of water and the non-aqueous converting agent and a small amount of sodium hydroxide was added. The concentration of sodium hydroxide in the final grease was 0.09%.
• the grease was made as follows: 495.18 grams of 400 TBN overbased oil-soluble calcium sulfonate were added to an open mixing vessel followed by 392.56 grams of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600 SUS at 38°C (100 F). Mixing without heat began using a planetary mixing paddle.
• the 400 TBN overbased oil-soluble calcium sulfonate was a good quality calcium sulfonate similar to the one previously described and used in Examples 4 and 12 of the ⁇ 768 application. Then 20.31 grams of a primarily C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 0.88 grams of powdered sodium hydroxide were dissolved in 44.0 grams water, and the resulting solution was added. Then the mixture was heated to 190 F (a first temperature adjustment delay period), and 16.73 grams of hexylene glycol and 6.16 grams of glacial acetic acid were added.
• Example 24 grease When the grease cooled to 77°C (170 F), it was removed from the mixer and given three passes through a three-roll mill to achieve a final smooth homogenous texture.
• the dropping point of the Example 24 grease was 478 F.
• the grease had a worked 60 stroke penetration of 311.
• the percent overbased oil-soluble calcium sulfonate in the final grease was 52.95%.
• the complex grease examples show that utilizing embodiments of the alkali/delayed addition method consistently improved thickener yield regardless of which previously documented calcium sulfonate-based grease technology is used. Additionally, the thickener yield improvement is observed regardless of whether the overbased calcium sulfonate used was good or poor quality, as defined in the ⁇ 768 application, although greater improvements are achieved with poor quality calcium sulfonates within the range of example compositions included herein (which is contrary to what would be expected).
• Example greases made according to the alkali/delayed addition methods of the invention described above also show different physical properties compared to example greases where addition of all or some of a non-aqueous converting agent was not delayed, even though the ingredients and quantities thereof used in various comparison sets of the examples were the same or substantially similar.
• FTIR Fourier Transform Infrared Spectroscopy
• SEM Scanning Electron Microscopy
• an open vessel is any vessel with or without a top cover or hatch as long as any such top cover or hatch is not vapor-tight so that significant pressure cannot be generated during heating.
• Using such an open vessel with the top cover or hatch closed during the conversion process will help to retain the necessary level of water as a converting agent while generally allowing a conversion temperature at or even above the boiling point of water.
• Such higher conversion temperatures can result in further thickener yield improvements for both simple and complex calcium sulfonate greases, as will be understood by those with ordinary skill in the art.
• thickener yield shall be the conventional meaning, namely, the concentration of the highly overbased oil-soluble calcium sulfonate required to provide a grease with a specific desired consistency as measured by the standard penetration tests ASTM D217 or D1403 commonly used in lubricating grease manufacturing.
• the "dropping point” of a grease shall refer to the value obtained by using the standard dropping point test ASTM D2265 as commonly used in lubricating grease manufacturing.
• reference to the immediate addition of an ingredient after a temperature has been reached means that the ingredient is added as soon after reaching that temperature as is physically possible given the amount to be added and equipment being used, but if preferably within a short time, less than 10 minutes and more preferably less than 5 minutes, after the mixture reaches approximately the temperature indicated.
• quantities of dispersed calcium carbonate (or amorphous calcium carbonate) or residual calcium oxide or calcium hydroxide contained in the overbased calcium sulfonate are by weight of the overbased calcium sulfonate; (2) some ingredients are added in two or more separate portions and each portion may be described as a percentage of the total amount for that ingredient; and (3) all other amounts (including total amounts) of ingredients identified by percentages or parts are the amounts added as an ingredient by weight of the final grease product, even though the particular ingredient (such as water, or calcium-containing bases or alkali metal hydroxides that react with other ingredients) may not be present in the final grease or may not be present in the final grease in the quantity identified for addition as an ingredient.
• the particular ingredient such as water, or calcium-containing bases or alkali metal hydroxides that react with other ingredients
• added calcium carbonate means crystalline calcium carbonate that is added as a separate ingredient in addition to the amount of dispersed calcium carbonate contained in the overbased calcium sulfonate.
• added calcium hydroxide and “added calcium oxide” means calcium hydroxide and calcium oxide, respectively, that are added as a separate ingredient in addition to the amount of residual calcium hydroxide and/or calcium oxide that may be contained in the overbased calcium sulfonate.
• calcium hydroxyapatite means (1) the compound having the formula Ca 5 (PO 4 ) 3 OH or (2) a mathematically equivalent formula (a) having a melting point of around 1100 C or (b) specifically excluding mixtures of tricalcium phosphate and calcium hydroxide by such equivalent formula.

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