CN108463542B

CN108463542B - Method for preparing calcium sulfonate grease by using non-aqueous conversion agent with delayed addition

Info

Publication number: CN108463542B
Application number: CN201680078416.2A
Authority: CN
Inventors: 安德鲁·J·韦尼克
Original assignee: NCH Corp
Current assignee: NCH Corp
Priority date: 2016-01-07
Filing date: 2016-12-14
Publication date: 2020-03-17
Anticipated expiration: 2036-12-14
Also published as: WO2017119999A1; EP3400279A1; CN108463542A; EP3400279A4

Abstract

A method of preparing an overbased calcium sulfonate grease comprising a reduced amount of overbased calcium sulfonate, water, and at least one non-aqueous converting agent, wherein at least a portion of the non-aqueous converting agent is added after one or more delay periods relative to the addition of water. The delay period can relate to a period of time required to adjust the temperature of the mixture, a period of time during which the mixture is maintained at a temperature or temperature range, and a plurality and any combination thereof. These calcium sulfonate greases have improved thickener yields and high dropping points compared to greases of substantially similar compositions prepared without delay between the addition of water and non-aqueous converting agent, particularly when poor quality overbased calcium sulfonates are used.

Description

Method for preparing calcium sulfonate grease by using non-aqueous conversion agent with delayed addition

Citations to related applications

This application claims priority to U.S. application serial No. 14/990,473 filed on day 1, 7, 2016, which is a continuation-in-part application of U.S. application serial nos. 13/664,574 and 13/664,768 filed on day 10, 31, 2012, and both claim the benefit of U.S. provisional application serial No. 61/553,674 filed on day 10, 31, 2012.

1. Field of the invention

The present invention relates to overbased calcium sulfonate greases (greases) prepared by delayed addition of a non-aqueous converting agent and methods for making such greases to provide improvements in thickener yield (thickener yield) and the expected high temperature utility as evidenced by drop points (dropping points), even when the oil-soluble overbased calcium sulfonates used to make the greases are considered to be of poor quality.

2. Background of the invention

Overbased calcium sulfonate greases have been the established grease class for many years. One known method of making such greases is a two-step process involving "boost" and "conversion" steps. Typically, the first step ("boosting") is to make a stoichiometric excess of calcium oxide (CaO) or calcium hydroxide (Ca (OH) as an alkali source₂) With alkylbenzenesulfonic acid, carbon dioxide (CO)₂) And reacting with other components to produce an oil-soluble overbased calcium sulfonate having amorphous calcium carbonate dispersed therein. These overbased oil-soluble calcium sulfonates are generally transparent and bright and have newtonian rheology. In some cases they may be slightly hazy, but this change does not prevent their use for preparing overbased calcium sulfonate greases. For the purposes of this disclosure, the terms "overbased oil-soluble calcium sulfonate" and "oil-soluble overbased calcium sulfonate" and "overbased calcium sulfonate" refer to any overbased calcium sulfonate suitable for use in preparing calcium sulfonate greases. Typically, the second step ("conversion") is to add one or more converting agents such as propylene glycol, isopropanol, water, formic acid or acetic acid along with a suitable base oil (e.g., mineral oil), if necessary, to the product of the promoting step to keep the initial grease not too hard to convert the amorphous calcium carbonate to a finely divided crystalline calcium carbonate. When acetic acid or other acids are used as converting agents, water and another non-aqueous converting agent (a third converting agent, such as an alcohol) are also typically used; alternatively, only water is added (without the third conversion agent), but then conversion typically occurs in a pressurized vessel. Since 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 crystalline form of calcium carbonate is preferably calcite. This finely divided calcium carbonate (also referred to as a colloidal dispersion) interacts with the calcium sulfonate to form a grease-like consistency. Such an overbased calcium sulfonate grease produced by a two-step process has been referred to as a "simple calcium sulfonate grease (single calcium sulfonate grease)", and is disclosed in, for example, a single calcium sulfonate greaseU.S. patent nos. 3,242,079, 3,372,115; 3,376,222, 3,377,283, and 3,492,231.

It is also known in the art to combine these two steps into one step by carefully controlling the reaction. In this one-step process, a simple calcium sulfonate grease is prepared by the reaction of an appropriate sulfonic acid with calcium hydroxide or calcium oxide in the presence of carbon dioxide and a system that simultaneously acts as both an accelerator (producing amorphous calcium carbonate that is overbased by the reaction of carbon dioxide with excess calcium oxide or calcium hydroxide) and a conversion agent (converting amorphous calcium carbonate to finely divided crystalline calcium carbonate). Thus, a grease-like consistency is formed in one 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. The one-step process is disclosed in, for example, U.S. patent nos. 3,661,622, 3,671,012, 3,746,643, and 3,816,310.

In addition to simple calcium sulfonate greases, calcium sulfonate complex greases are also known in the prior art. These complex greases are typically prepared by adding a strong calcium-containing base such as calcium hydroxide or calcium oxide to a simple calcium sulfonate grease produced by a two-step or one-step process, and reacting with up to a stoichiometric equivalent of a complexing acid such as 12-hydroxystearic acid, boric acid, acetic acid (which may also be a converting agent when added prior to conversion), or phosphoric acid. Reported advantages of calcium sulfonate complex greases over simple greases include reduced viscosity, improved pumpability, and improved high temperature utility. Calcium sulfonate complex greases are disclosed in, for example, U.S. Pat. nos. 4,560,489, 5,126,062, 5,308,514, and 5,338,467.

Many of the known prior art using a two-step process teaches the addition of all of the converting agents (water and non-aqueous converting agents) simultaneously with and typically prior to heating. However, some prior art references disclose the time interval between the addition of water and the addition of at least part of one or more non-aqueous conversion agents (although always undefined or not defined at all). For example, U.S. Pat. No. 4,560,489 discloses a process (examples 1-3) in which a base oil and overbased calcium carbonate are heated to about 150 ° F, then water is added, and then the mixture is heated to about 190 ° F before adding acetic acid and methyl cellosolve (the highly toxic monomethyl ether of ethylene glycol). The resulting grease contains greater than 38% overbased calcium sulfonate, and the '489 patent notes that the desirable amount of overbased calcium sulfonate for the process disclosed therein is about 41-45%, since less than 38% used according to the' 489 patent results in a soft grease. The resulting grease of example 1 in the' 489 patent has a drop point of only about 570 ° F. The' 489 patent does not describe a delay period between the addition of water and the addition of the non-aqueous conversion agent, but indicates that the addition occurs immediately after the period of heating from 150F to just 190F. The drop point and thickener yield in the' 489 patent are not desirable.

Further, U.S. Pat. nos. 5,338,467 and 5,308,514 disclose the use of fatty acids such as 12-hydroxystearic acid as a conversion agent for use with acetic acid and methanol, where there is no delay in the addition of the fatty acid, but there is some time 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 method in which water and a fatty acid conversion agent are added to the other ingredients, including overbased calcium sulfonate and base oil, and then heated to about 140F and 145F before adding acetic acid and then methanol. The mixture is then heated to about 150 and 160F until conversion is complete. The amount of overbased calcium sulfonate in the final grease product in both examples was 32.2, which was higher than desired. These patents do not describe the delay period between the addition of water and fatty acid and the addition of acetic acid and methanol, but show addition immediately after an unspecified heating time. Similar processes are disclosed in example A of the '467 patent and example C of the' 514 patent, except that all of the fatty acids are added after conversion, so the only non-aqueous converting agents used are acetic acid and methanol added after heating the mixture with water to 140-145F. In these examples, the amount of overbased calcium sulfonate was even 40% higher than in the previous examples. All of these processes use methanol as a conversion agent, which has environmental drawbacks, except that the desired thickener yield results are not achieved. The use of volatile alcohols as converting agents may result in the emission of these components into the atmosphere as a later part of the grease manufacturing process prohibited in many regions of the world. If not discharged, the alcohol must be recovered by water washing or a water trap (water trap), which results in hazardous material disposal costs. Therefore, there is a need for a process to obtain better thickener yield, preferably without the need to use volatile alcohols as converting agents.

Better thickener yields were obtained in example 10 of the' 514 patent, but the use of excess lime was considered a requirement to achieve these results. In this example, water and excess lime were added along with the other ingredients, and the mixture was heated to 180F and 190F while acetic acid was slowly added during the heating. The grease obtained contained 23% overbased calcium sulfonate. Although the thickener yield is superior to others, there is still more room for improvement without the use of excess lime, which is taught by the' 514 patent.

Other examples of the '514 and' 467 patents in which there is a thickener yield of 23% or less include the use of an autoclave during conversion, or as in a much larger portion of other prior art where there is no "delay" between the addition of water and non-aqueous converting agent or both. These examples include adding water and fatty acid converting agent, mixing for 10 minutes without heating, and then adding acetic acid, either in an autoclave or without pressure. None of these patents recognize any benefit or advantage of the 10 minute intervals of acetic acid addition or other heating delays in the above discussed examples, but instead these patents focus on the use of fatty acids as converting agents, and the benefit of adding fatty acids before conversion, after conversion, or both, as the cause of any observed yield improvement. Furthermore, as discussed below, this 10 minute mixing time interval without any heating is not a "delay" in the term used herein, but is considered the same as adding the ingredients simultaneously, recognizing that adding each ingredient requires at least some time and cannot occur instantaneously.

Furthermore, the known prior art consistently teaches the use of calcium oxide or calcium hydroxide as a source of basic calcium for the production of calcium sulfonate greases or as a required component to react with a complex acid to form calcium sulfonate complex greases. The known prior art teaches that the addition of calcium hydroxide or calcium oxide requires a sufficient amount (when added to an amount of calcium hydroxide or calcium oxide present in the highly basic oil-soluble calcium sulfonate) to provide a total amount of calcium hydroxide or calcium oxide sufficient to react well with the complex acid. As disclosed in co-pending U.S. application serial nos. 13/664,574 and 13/664,768, the known prior art generally teaches that calcium carbonate (as a separate ingredient or as an "impurity" in calcium hydroxide or calcium oxide, except for the presence of amorphous calcium carbonate dispersed in calcium sulfonate after carbonation) should be avoided for at least two reasons. First, calcium carbonate is generally considered to be a weak base and is not suitable for reaction with complex acids to form the optimum grease structure. The second reason is that the presence of unreacted solid calcium compounds (including calcium carbonate, calcium hydroxide or calcium oxide) interferes with the conversion process, resulting in poor grease quality if the unreacted solids are not removed prior to conversion or prior to completion of conversion. However, applicants have found that the addition of calcium carbonate as a separate component (in addition to the amount of calcium carbonate contained in the overbased calcium sulfonate), calcium hydroxyapatite (calcium hydroxyapatite), or a combination thereof (with or without the addition of calcium hydroxide or calcium oxide) as the component for reaction with the complex acid produces a grease of superior quality as described in the '574 and' 768 applications.

There are several prior art references disclosing the addition of crystalline calcium carbonate as a separate ingredient (in addition to the amount of calcium carbonate contained in the overbased calcium sulfonate), but these greases have poor thickener yields (as taught by the prior art) or require nano-sized particles of calcium carbonate. For example, U.S. patent No. 5,126,062 discloses the addition of 5-15% calcium carbonate as a separate component to form a complex grease, but also requires the addition of calcium hydroxide to react with the complex acid. In the' 062 patent, the added calcium carbonate is not the only added calcium-containing base used to react with the complex acid. In fact, the added calcium carbonate is not particularly added as an alkaline reactant to react with the complex acid. Instead, the added calcium hydroxide is required as a specific calcium-containing base to react with all complex acids. In addition, the resulting NGLI No. 2 grease contains 36% to 47.4% overbased calcium sulfonate, which is a significant amount of this expensive ingredient. In another example, chinese publication CN101993767 discloses the addition of nano-sized particles of calcium carbonate (between 5-300nm in size) to overbased calcium sulfonates, although the reference does not suggest the addition of nano-sized particles of calcium carbonate as a reactant, or the addition of only a calcium-containing base alone for reaction with a complex acid. The use of nano-sized particles increases the consistency of the grease to maintain its consistency much like a fine dispersion of crystalline calcium carbonate (which may be about 20A to 5000A or about 2nm to 500nm according to the' 467 patent) formed by conversion of amorphous calcium carbonate contained in overbased calcium sulfonate, but also at a substantially increased cost compared to larger sized added calcium carbonate particles. The chinese patent application largely underscores the absolute necessity of adding calcium carbonate having a true nano-particle size. As shown in the exemplary grease according to the present invention described in the co-pending' 574 application, a premium grease may be formed by the addition of micron-sized calcium carbonate without the need to use very expensive nano-sized particles, and when the added calcium carbonate is used as one or with the sole addition of a calcium-containing base to react with a complex acid.

There are also prior art references that use tricalcium phosphate as an additive in greases. For example, U.S. patent nos. 4,787,992, 4,830,767, 4,902,435, 4,904,399, 4,929,371 all teach the use of tricalcium phosphate as an additive for grease. However, none of the prior art references is believed to teach the use of a compound having the formula Ca₅(PO₄)₃Calcium hydroxyapatite OH or a mathematical equivalent having a melting point of about 1100C is used as the calcium-containing base for reaction with an acid to make greases, including calcium sulfonate-based greases. There are several prior art references to Showa Shell Sekiyu in Japan including U.S. patent application publication No. 2009/0305920, which describes the inclusion of tricalcium phosphate Ca₃(PO₄)₂And the reference has the formula [ Ca₃(PO₄)₂]3·Ca(OH)₂The "hydroxyapatite" of (a) serves as a source of tricalcium phosphate. This reference to "hydroxyapatite" is disclosed as a mixture of tricalcium phosphate and calcium hydroxide, which reacts with the 768 patentThe calcium hydroxyapatite disclosed and claimed in the application is different and has the formula Ca here₅(PO₄)₃OH or mathematical equivalent, and a melting point of about 1100C. Despite misleading nomenclature, calcium hydroxyapatite, tricalcium phosphate, and calcium hydroxide are each different compounds having different chemical formulas, structures, and melting points. When mixed together, two different crystalline compounds tricalcium phosphate (Ca)₃(PO₄)₂) And calcium hydroxide (Ca (OH)₂) Do not react with each other or otherwise produce different crystalline compounds calcium hydroxyapatite (Ca)₅(PO₄)₃OH). Tricalcium phosphate (having the formula Ca)₃(PO₄)₂) Has a melting point of 1670C. Calcium hydroxide does not have a melting point, but loses water molecules at 580C to form calcium oxide. The calcium oxide thus formed had a melting point of 2580C. Calcium hydroxyapatite (having the formula Ca₅(PO₄)₃OH or mathematical equivalent) has a melting point of about 1100C. Thus, regardless of how inaccurate the nomenclature may be, calcium hydroxyapatite is not the same compound as tricalcium phosphate, and it is not a simple blend of tricalcium phosphate and calcium hydroxide.

Furthermore, it would be desirable to have a calcium sulfonate complex grease composition and method of making the same to result in improved thickener yield and drop point. Many known prior art compositions require overbased calcium sulfonates in amounts of at least 36% (by weight of the final grease product) to obtain suitable greases in NGLI category No. 2 that have a verified drop point of at least 575F. Overbased oil-soluble calcium sulfonates are one of the most expensive ingredients to make calcium sulfonate greases, and it is therefore desirable to reduce the amount of this ingredient while still maintaining the desired hardness level of the final grease (thereby increasing thickener yield). To achieve a substantial reduction in the amount of overbased calcium sulfonates used, many prior art references utilize pressure reactors. Overbased calcium sulfonate greases are desired in which the percentage of overbased oil-soluble calcium sulfonate is below 36% when the consistency is in NLGI No. 2 rating (or working 60stroke penetration of grease (60 stroke working penetration, used 60stroke penetration, working penetration 60stroke, working penetration after 60 strokes) is between 265 and 295), and the drop point is consistently 575F or higher without the need for a pressure reactor. Higher drop points are considered desirable because the drop point is the first and most easily determined guide for the high temperature utility limit of the grease.

Disclosure of Invention

The present invention relates to overbased calcium sulfonate greases and methods of making such greases to provide improvements in thickener yield (less overbased calcium sulfonate is required while maintaining acceptable penetration measurements) and desirable high temperature utility (as evidenced by the drop point). According to a preferred embodiment of the present invention, a simple (single, primary) calcium sulfonate grease is prepared by reacting and mixing certain compounds comprising: (a) a primary overbasing material comprising an overbased oil-soluble calcium sulfonate with dispersed amorphous calcium carbonate; (b) optionally, if desired, a suitable base oil to provide an acceptable consistency to the product after conversion (any amount of added base oil may be added before conversion, after conversion, or both); (c) water as a conversion agent; and (d) one or more other converting agents (non-aqueous converting agents), wherein there are one or more lag periods between the addition of water prior to conversion and the addition of at least a portion of the one or more other non-aqueous converting agents prior to conversion. As used herein, "non-aqueous conversion agent" refers to any conversion agent other than water, and includes conversion agents that may contain some water as a diluent or impurity.

According to another preferred embodiment of the present invention, the complex calcium sulfonate grease is prepared by reacting and mixing certain compounds comprising: (a) a primary overbasing material comprising an overbased oil-soluble calcium sulfonate with dispersed amorphous calcium carbonate; (b) optionally, if desired, a suitable base oil to provide an acceptable consistency to the product after conversion (any amount of added base oil may be added before conversion, after conversion, or both); (c) water as a conversion agent; (d) one or more other converting agents (non-aqueous converting agents); (d) one or more complex acids; and (e) one or more added calcium-containing bases for reaction with one or more complex acids; wherein there is one or more lag periods between the addition of water prior to conversion and the addition of at least a portion of the one or more other non-aqueous conversion agents prior to conversion. All of the one or more complex acids may be added before or after the conversion. Alternatively, a portion of the one or more complex acids may be added prior to conversion of the calcium sulfonate complex grease and the remainder of the one or more complex acids may be added after conversion. All of the one or more calcium containing bases may be added before or after the transformation. Alternatively, a portion of one or more calcium-containing bases may be added prior to conversion and 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 base for reaction with the complex acid. Preferably, no excess of calcium hydroxide relative to the total amount of complex acid used is added prior to the conversion.

According to another preferred embodiment, the one or more delay periods (the time between the pre-conversion addition of water and the pre-conversion addition of at least a portion of the non-aqueous conversion agent) is a temperature regulation delay period or a holding delay period or both. If additional water is added to compensate for evaporation losses prior to conversion during the manufacturing process, those additions are not used to restart or determine the delay period, and only the first addition of water is used as a starting point for determining the delay period. The delay period may include a plurality of temperature adjustment delay periods and/or a plurality of hold delay periods. For example, the first temperature adjustment delay period is the amount of time it takes to heat the mixture to a certain temperature or a certain temperature range (first temperature) after adding water. The first hold delay period is the amount of time the mixture is held at the first temperature before heating or cooling to another temperature or before adding at least a portion of the non-aqueous conversion agent. The second temperature adjustment delay period is the amount of time it takes to heat or cool the mixture to another temperature or temperature range (the second temperature) after the first hold delay period. The second hold delay period is the amount of time the mixture is held at the second temperature before heating or cooling to another temperature or before adding at least a portion of the non-aqueous conversion agent. The additional temperature adjustment delay period or the hold delay period (i.e., the third temperature adjustment delay period) follows the same pattern. Typically, the hold delay period precedes or follows the temperature adjustment delay period, and vice versa, but there may be two back-to-back (back to back) hold delay periods or two back-to-back temperature adjustment periods. For example, the mixture may be kept at ambient temperature for 30 minutes before adding one non-aqueous conversion agent (first holding delay period) and may be kept at ambient temperature for another hour before adding the same or a different non-aqueous conversion agent (second holding delay period). Further, the mixture may be heated or cooled to a first temperature, followed by addition of the non-aqueous conversion agent (first temperature conditioning period), and then the mixture is heated or cooled to a second temperature, followed by addition of the same or a different non-aqueous conversion agent (second temperature conditioning period, without any intermediate holding period). Furthermore, a portion of the non-aqueous conversion agent need not be added after each lag period, but the lag period may be skipped before or between additions. For example, the mixture may be heated to a temperature (a first temperature adjustment delay period) and then held at that temperature for a period of time (a first hold delay period) before any non-aqueous conversion agent is added.

According to a preferred embodiment, the first temperature may be ambient temperature or another temperature. Any subsequent temperature may be higher or lower than the previous temperature. The final pre-conversion temperature (for non-pressurized production) will be about 190 ° F to 220 ° F or up to 230 ° F, as is the temperature at which conversion typically occurs in an open kettle. The final pre-conversion temperature may be below 190F, but such process conditions typically result in significantly longer conversion times and thickener yields may also be reduced. If a portion of the non-aqueous conversion agent is added immediately after a certain temperature or temperature range is reached, there is no hold time delay for that particular temperature and that portion of the non-aqueous conversion agent; however, if another portion is added after a hold at that temperature or temperature range for a period of time, there is a lag in incubation time for that temperature and that portion of the non-aqueous conversion agent. A portion of the one or more non-aqueous conversion agents may be added after any temperature-adjusted delay period or holding delay period, and another portion of the same or different non-aqueous conversion agent may be added after another temperature-adjusted delay period or holding delay period.

According to another preferred embodiment, at least a portion of the non-aqueous converting agent is added after the mixture is heated to a final pre-conversion temperature range of about 190F to 230F. According to another preferred embodiment, no amount of non-aqueous converting agent is added substantially simultaneously with the addition of water, and there is at least one delay period before any non-aqueous converting agent is added. According to another preferred embodiment, when the at least one non-aqueous converting agent is a glycol (e.g. propylene glycol or hexylene glycol), a portion of the glycol is added substantially simultaneously with water, and another portion of the glycol and all other non-aqueous converting agents are added after at least one delay period. According to another preferred embodiment, when acetic acid is added before conversion, it is added substantially simultaneously with water, and after a delay period another (different) non-aqueous conversion agent is added. According to another preferred embodiment, the alcohol is not used as a non-aqueous converting agent.

According to a preferred embodiment, after the delay period, all or part of the non-aqueous conversion agent is added in a batch-wise manner (all at once, as opposed to continuously during the delay period described below). It should be noted, however, that in large scale or commercial scale operations, due to the volumes of materials involved, some time is required to complete the batch addition of such non-aqueous converting agent to the grease batch. In a batch addition, the amount of time it takes to add the non-aqueous conversion agent to the grease mixture is not considered a lag phase. In this case, any delay before adding the non-aqueous conversion agent or part thereof ends at the beginning of the batch addition of non-aqueous conversion agent. According to another preferred embodiment, at least one or part of one non-aqueous conversion agent is added in a continuous manner during the course of the delay period (thermoregulation delay period or maintenance delay period). Such continuous addition may be achieved by slow addition of the non-aqueous conversion agent at a substantially steady flow rate or by repeated, discrete incremental additions during the temperature adjustment delay period, the holding delay period, or both. In this case, the time taken for the complete addition of the non-aqueous conversion agent is included in the delay period, which ends when the addition of the non-aqueous conversion agent is completed. According to another preferred embodiment, at least one part of one non-aqueous converting agent is added in a batch-wise manner after the delay period, and at least another part of the same or a different non-aqueous converting agent is added in a continuous manner during the delay period.

According to another preferred embodiment of the invention, at least one delay period is used to achieve improved thickener yield results even when overbased calcium sulfonates are considered "poor quality". Certain overbased oil-soluble calcium sulfonates that are commercially available and sold for use in the manufacture of calcium sulfonate-based greases may provide an unacceptably low drop point for the product when using prior art calcium sulfonate technology. This overbased oil-soluble calcium sulfonate is referred to herein as "poor quality" overbased oil-soluble calcium sulfonate. When all ingredients and methods are the same except that commercial batches of overbased calcium sulfonate are used, overbased oil-soluble calcium sulfonates that produce greases with higher drop points (above 575F) are considered the "good" qualities of calcium sulfonate for purposes of the present invention, and those that produce greases with lower drop points are considered the "bad" qualities for purposes of the present invention. Several examples of which are provided in the' 768 application incorporated by reference. Although comparative chemical analysis of overbased oil-soluble calcium sulfonates of good and poor quality has been performed, it is believed that the exact cause of this low drop point problem has not been confirmed. Although most commercially available overbased calcium sulfonates are considered to be good quality, whether good or poor quality calcium sulfonates are used, it is desirable to achieve both increased thickener yield and higher drop points. It has been found that when using the delayed addition method according to the invention, an increased thickener yield and a higher drop point can be achieved with a good or poor quality of the calcium sulfonate. Indeed, when at least some of the preferred embodiments of the invention are used, the results of the examples using low quality overbased calcium sulfonates even show better thickener yields than those using high quality overbased calcium sulfonates. According to another preferred embodiment, when the at least one non-aqueous converting agent is a diol (e.g. propylene glycol or hexylene glycol), all diols are added after at least one delay period (none added with water) and a poor quality of calcium sulfonate is used.

When produced according to the parameters of the invention described herein, consistently high quality calcium sulfonate greases can be prepared with thickener yields and dropping point properties superior to those of prior art greases. An overbased calcium sulfonate complex grease prepared in accordance with a preferred embodiment of the present invention has a NLGI No. 2 grade consistency (or better, i.e., harder) and a drop point of 575 ° F (or higher), wherein the percentage of overbased oil-soluble calcium sulfonate when prepared in an open container (without pressure) is about 10% to 45%. More preferably, the amount of overbased oil-soluble calcium sulfonate in greases prepared according to preferred embodiments of the present invention is at least about 10% but about 36% or less, more preferably about 30% or less, and most preferably about 22% or less when manufactured in an open container (without pressure). These improved thickener yields are achieved with both high and low quality overbased calcium sulfonates. Even higher thickener yields can be achieved using the process of the invention when making greases in pressurized containers. Most preferably, a drop point of over 650F is achieved. The lower concentration of overbased oil-soluble calcium sulfonates achieved by the present invention is desirable due to the reduced cost of the greases. The improved thickener yield achieved according to the invention can also favorably influence other properties, such as flowability and pumpability, especially at lower temperatures.

The overbased calcium sulfonate simple grease prepared in accordance with a preferred embodiment of the present invention has a NLGI No. 2 grade consistency and a drop point of 575 ° F (or greater), wherein the percentage of overbased oil-soluble calcium sulfonate is from about 30% to 70%, and most preferably from about 45% to 54%. If a softer grease is desired, a lesser percentage of overbased oil-soluble calcium sulfonate will be required, as is well known to those of ordinary skill in the art. Although the present invention is primarily directed to greases prepared in open containers, it may also be used in closed containers where heating under pressure is accomplished. The use of such pressurized containers may result in even better thickener yields. For the purposes of this invention, an open container is any container with or without a cover or hatch, provided that any such cover or hatch is not gas tight and therefore does not generate significant pressure during heating. The use of such an open vessel closed by a cover or hatch during the conversion process will help to maintain the necessary amount of water as the conversion agent, while generally allowing the conversion temperature to be at or even above the boiling point of water. As understood by those of ordinary skill in the art, such higher conversion temperatures may result in further thickener yield improvements for both simple and complex calcium sulfonate greases.

Detailed Description

According to a preferred embodiment of the present invention, a simple calcium sulfonate grease is prepared by reacting and mixing certain compounds comprising: (a) a primary overbasing material comprising an overbased oil-soluble calcium sulfonate with dispersed amorphous calcium carbonate; (b) optionally, if desired, a suitable base oil to provide an acceptable consistency to the product after conversion (any amount of added base oil may be added before conversion, after conversion, or both); (c) water as a conversion agent; and (d) one or more other converting agents (non-aqueous converting agents), wherein there are one or more lag periods between the addition of water and the addition of at least a portion of the one or more other non-aqueous converting agents prior to conversion.

According to another preferred embodiment of the present invention, the complex calcium sulfonate grease is prepared by reacting and mixing certain compounds comprising: (a) a primary overbasing material comprising an overbased oil-soluble calcium sulfonate with dispersed amorphous calcium carbonate; (b) optionally, if desired, a suitable base oil to provide an acceptable consistency to the product after conversion (any amount of added base oil may be added before conversion, after conversion, or both); (c) water as a conversion agent; (d) one or more other converting agents (non-aqueous converting agents), wherein there are one or more lag periods between the addition of water and the addition of at least a portion of the one or more other non-aqueous converting agents prior to conversion; (e) one or more complex acids; and (f) one or more added calcium-containing bases reacted with one or more complex acids. A portion of the one or more complex acids may be added prior to conversion of the calcium sulfonate complex grease and the remainder of the one or more complex acids may be 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 base for reaction with the complex acid.

In simple and complex greases, some or all of the ingredients (including the converting agent) may not be in the final finished product due to evaporation and volatilization during manufacture. Alternatively, for simple or complex greases, a promoting acid may be added prior to conversion according to another embodiment of the invention. This promoting acid assists in grease structure formation. For simple and complex greases according to the invention, there are one or more delay periods between the addition of water and the addition of at least a portion of the one or more other non-aqueous conversion agents prior to conversion. As described below with respect to the preferred method of preparing a calcium sulfonate grease according to the present invention, it is also most preferred that the mixture is heated to a temperature or temperature range during at least one or each of the delay periods. Most preferably, the one or more delay periods (the time between the pre-conversion addition of water and the addition of at least a portion of the non-aqueous conversion agent) is a temperature regulation delay period or a holding delay period or both. The delay period may include a plurality of temperature adjustment delay periods and a plurality of hold delay periods. For example, the first temperature adjustment delay period is a period of time taken to change the temperature of the mixture to a desired temperature or temperature range (first temperature) after adding water. The first holding delay period is the amount of time the mixture is held at the first temperature. The second temperature adjustment delay period is the period of time it takes to heat or cool the mixture to another temperature or temperature range (the second temperature) after the first hold delay. The second hold delay period is the amount of time the mixture is held at the second temperature. The additional temperature adjustment delay period and the hold delay period (i.e., the third temperature adjustment delay period) follow the same pattern. The first temperature may be ambient or elevated. Any subsequent temperature may be higher or lower than the previous temperature. The final pre-conversion temperature will be about 190 ° F to 220 ° F or up to 230 ° F, as is the temperature at which conversion typically occurs in an open kettle. Any combination of temperature adjustment delay period and/or hold delay period may be used.

If the non-aqueous converting agent or portion thereof is added immediately after a certain temperature or temperature range is reached, no delay period is maintained for that particular temperature. A portion of the one or more non-aqueous conversion agents may be added after any temperature-adjusted delay period or holding delay period, and another portion of the same or different non-aqueous conversion agent may be added after another temperature-adjusted delay period or holding delay period. Typically, the duration of each thermoregulation 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 regulation delay period will vary depending on the size of the grease batch, the equipment used to mix and heat the batch, and the temperature difference between the starting and final temperatures, as will be appreciated by those of ordinary skill in the art. Preferred embodiments regarding the one or more delay periods are further discussed below regarding preferred methods for manufacturing a grease according to the present invention.

The highly overbased oil-soluble calcium sulfonates used in accordance with these embodiments of the present invention may be any of those typically described in the 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 have a Total Base Number (TBN) value of not less than 200, preferably not less than 300, and most preferably about 400 or more. Commercially available overbased calcium sulfonates of this type include, but are not limited to, the following: hybase C401 supplied by chemtura usa; syncal OB 400 and Syncal OB405-WO, supplied by Kimes Technologies International corporation; lubrizol75GR, Lubrizol75 NS, Lubrizol75P and Lubrizol75 WO supplied by Lubrizol corporation. The overbased calcium sulfonate contains from about 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 from about 0% to 8% residual calcium oxide or calcium hydroxide by weight of the overbased calcium sulfonate. Most commercially available overbased calcium sulfonates also contain about 40% base oil as a diluent to prevent the overbased calcium sulfonate from being so viscous that it is difficult to handle and process. The amount of base oil in the overbased calcium sulfonate may be such that the addition of additional base oil (as a separate ingredient) prior to conversion to obtain an acceptable grease is unnecessary. The overbased calcium sulfonates used may be of good or poor quality as defined herein and in the' 768 application.

The amount of highly overbased oil-soluble calcium sulfonate in the final compound grease according to embodiments of the present invention may vary, but is typically from 10 to 45%. Preferably, the amount of highly overbased oil-soluble calcium sulfonate in the final compound grease according to embodiments of the present invention is about 36% or less, more preferably about 30% or less, and most preferably about 22% or less when prepared in an open vessel (without pressure), even smaller percentages being obtainable when prepared in a pressure vessel. The amount of highly overbased oil-soluble calcium sulfonate in the final simple grease according to embodiments of the present invention may vary, but is typically from 30 to 70%, more preferably less than 60%, and most preferably less than 55%.

In some cases, synthetic base oils, if present during the conversion, may have adverse effects, as understood by those of ordinary skill in the art, in which case those synthetic base oils should not be added initially, but rather added to the grease manufacturing process at a stage where adverse effects are eliminated or minimized (e.g., after conversion), preferably the amount of naphthenic and paraffinic base oils added is preferably increased to 70% by weight based on the total amount of base oil added, preferably 70% by weight, and the amount of basic oil added later, preferably increased to 70% by weight based on the total amount of base oil added, preferably 70% by weight, as typical grease additive amount, preferably 70% by weight, and the amount of basic oil added is preferably increased to 70% by weight based on the total amount of basic oil added, preferably 70% by weight, as the amount of basic oil added later.

Water is added as a converting agent to the preferred embodiment of the present invention. Preferably, one or more other non-aqueous converting agents are also added in these embodiments of the invention. 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 compound containing an active hydrogen or a tautomeric hydrogen. Non-aqueous conversion agents also include those agents that contain some water as a diluent or impurity. Although they can be used as non-aqueous converting agents, it is preferred not to use alcohols such as methanol or isopropanol or other low molecular weight (i.e. more volatile) alcohols due to environmental concerns and limitations associated with hazardous waste disposal of vented gases or wash alcohols during grease preparation. The total amount of water added as converting agent is 1.5% to 10%, preferably 2.0% to 5.0%, most preferably 2.2% to 4.5%, based on the final weight of the grease. Additional water may be added after conversion. Also, if the conversion is carried out in an open vessel at a sufficiently high temperature to volatilize most of the water during the conversion, additional water may be added to replace the lost water. The total amount of the one or more non-aqueous converting agents added is from 0.1% to 5%, preferably from 0.5% to 4%, most preferably from 1.0% to 3.0%, based on the final weight of the grease. Generally, the amount of non-aqueous converting agent used will decrease as the amount of overbased calcium sulfonate decreases. Depending on the converting agent used, some or all of them may be removed by volatilization during the manufacturing process. Particularly preferred are the lower molecular weight diols such as hexylene glycol and propylene glycol. It should be noted that some converting agents may also be used as complex acids to produce calcium sulfonate complex greases according to one embodiment of the invention discussed below. Such a material would provide both conversion and recombination functions.

Although not required, a small amount of a promoting acid may be added to the mixture prior to conversion in accordance with another embodiment of the present invention. Suitable promoting acids having an alkyl chain length of typically 8 to 16 carbons, such as alkyl benzene sulphonic acid, may help promote effective grease structure formation. Most preferably, the alkylbenzene sulfonic acid comprises a mixture of alkyl chain lengths of mostly about 12 carbons in length. This benzene sulfonic acid is commonly referred to as dodecylbenzene sulfonic acid ("DDBSA"). Commercially available benzenesulfonic acids of this type include JemPak 1298 sulfonic acid supplied by JemPak GK Inc., Calsoft LAS-99 supplied by Pilot chemical company and Biosoft S-101 supplied by Stepan chemical company. When alkyl benzene sulphonic acid is used in the present invention, it is added prior to conversion in an amount of from about 0.50% to 5.0%, preferably from 1.0% to 4.0%, most preferably from 1.3% to 3.6% based on the final weight of the grease. If the calcium sulfonate is prepared in situ using alkyl benzene sulfonic acid, the promoting acid added according to this embodiment is in addition to the acid required to produce the calcium sulfonate.

When preparing a complex calcium sulfonate grease according to another preferred embodiment of the present invention, one or more complex acids and one or more calcium-containing bases are also added. The calcium-containing base may include calcium hydroxyapatite, added calcium carbonate, added calcium hydroxide, added calcium oxide, or a combination of one or more of the foregoing. Calcium hydroxyapatite used as a calcium containing base to react with the complex acid according to this embodiment may be added before, after, or partially before and partially after the conversion. Most preferably, the calcium hydroxyapatite is finely divided to an average particle size of about 1 to 20 microns, preferably about 1 to 10 microns, most preferably about 1 to 5 microns. In addition, the calcium hydroxyapatite will be of sufficient purity so that the level of abrasive contaminants such as silica and alumina is sufficiently low so as not to significantly affect the antiwear properties of the resulting grease. Ideally, for optimal effect, the calcium hydroxyapatite should be food grade or usp grade. The amount of calcium hydroxyapatite added is from 2.0% to 20%, preferably from 4% to 15%, most preferably from 5% to 10% based on the total weight of the grease, although more may be added after conversion and completion of all reactions with the complex acid if desired.

According to another embodiment of the present invention, calcium hydroxyapatite may be added to the above ingredients in an amount insufficient to completely react with the complex acid. In this embodiment, finely divided calcium carbonate as an oil insoluble solid calcium containing base may preferably be added prior to conversion in an amount sufficient to fully react with and neutralize the portion of any subsequently added complex acid that is not neutralized by calcium hydroxyapatite.

According to another embodiment, calcium hydroxyapatite may be added to the above ingredients in an amount insufficient to completely react with the complex acid. In this embodiment, finely divided calcium hydroxide and/or calcium oxide as an oil insoluble solid calcium-containing base may preferably be added prior to conversion in an amount sufficient to react and neutralize with the portion of any subsequently added complex acid that is not neutralized by the co-added calcium hydroxyapatite. In this embodiment, calcium hydroxide and/or calcium oxide preferably represents no more than 75% of the hydroxide equivalent alkalinity provided by the total amount of calcium hydroxyapatite, calcium hydroxide and calcium oxide added. In another embodiment, the calcium carbonate may also be added with calcium hydroxyapatite, calcium hydroxide and/or calcium oxide, wherein the calcium carbonate is added before or after reaction with the complex acid. When the amount of calcium hydroxyapatite, calcium hydroxide and/or calcium oxide is insufficient to neutralize the added complex acid or acids, it is preferred that calcium carbonate be added in an amount greater than sufficient to neutralize any remaining complex acid or acids.

According to these embodiments of the invention, the added calcium carbonate used as a calcium-containing base, alone or in combination with one or more additional calcium-containing bases, is finely divided into an average particle size of about 1 to 20 microns, preferably about 1 to 10 microns, most preferably about 1 to 5 microns. Furthermore, the calcium carbonate added is preferably crystalline calcium carbonate (most preferably calcite) of sufficient purity so that the level of abrasive contaminants such as silica and alumina is sufficiently low so as not to significantly affect the antiwear properties of the resulting grease. Ideally, for optimal effect, the calcium carbonate should be food grade or usp grade. The amount of calcium carbonate added is from 2.0% to 20%, preferably from 4% to 15%, most preferably from 6% to 10%, based on the final weight of the grease. These amounts are added as separate ingredients in addition to the amount of dispersed calcium carbonate contained in the overbased calcium sulfonate. According to another preferred embodiment of the invention, the added calcium carbonate is added as the only added calcium-containing base component to react with the complex acid prior to conversion. Additional calcium carbonate may be added to the simple or complex grease embodiments of the present invention after conversion and after the complete reaction with the complex acid in the case of complex greases is complete. However, the added calcium carbonate referred to herein refers to calcium carbonate added prior to conversion and is the calcium-containing base used as one or the only addition to react with the complex acid in the preparation of the complex grease according to the present invention.

According to another embodiment the added calcium hydroxide and/or added calcium oxide added prior to conversion should be finely divided to an average particle size of about 1 to 20 microns, preferably about 1 to 10 microns, most preferably about 1 to 5 microns. In addition, the calcium hydroxide and calcium oxide will be of sufficient purity so that the level of abrasive contaminants, such as silica and alumina, is sufficiently low so as not to significantly affect the antiwear properties of the resulting grease. Ideally, for optimal effect, the calcium hydroxide and calcium oxide should be food grade or usp grade. The total amount of calcium hydroxide and/or calcium oxide is from 0.07% to 1.00%, preferably from 0.15% to 0.85%, most preferably from 0.18% to 0.40%, based on the total weight of the grease. These amounts are added as separate components in addition to the amount of residual calcium hydroxide or calcium oxide contained in the overbased calcium sulfonate. Most preferably, no excess of calcium hydroxide relative to the total amount of complex acid used is added prior to conversion. According to yet another embodiment, there is no need to add any calcium hydroxide or calcium oxide for reaction with the complex acid, and the added calcium carbonate or calcium hydroxyapatite may be used as the separately added calcium-containing base for such reaction or may be used in combination for such reaction.

The complex acid 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. Depending on the time of addition, acetic acid and other carboxylic acids may be used as converting agents or complex acids or both. Similarly, some complex acids (such as 12-hydroxystearic acid in the '514 and' 467 patents) may be used as conversion agents. The total amount of complex acid added is preferably from 2.8% to 11% by weight of the final grease. The long chain carboxylic acids suitable for use according to the present invention comprise aliphatic carboxylic acids having at least 12 carbon atoms. Preferably, the long chain carboxylic acid comprises an aliphatic carboxylic acid having at least 16 carbon atoms. Most preferably, the long chain carboxylic acid is 12-hydroxystearic acid. The amount of long chain carboxylic acid is from 0.5% to 5.0%, preferably from 1.0% to 4.0%, most preferably from 2.0% to 3.0%, based on the final weight of the grease.

Short chain carboxylic acids suitable for use according to the present invention comprise aliphatic carboxylic acids having 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 acid is from 0.05% to 2.0%, preferably from 0.1% to 1.0%, most preferably from 0.2% to 0.5%, based on the final weight of the grease. Any compound which is contemplated to react with water or other components used to produce the greases according to the invention for such reactions to produce long or short chain carboxylic acids is also suitable for use. For example, acetic anhydride will be used to form acetic acid to be used as the complex acid by reaction with water present in the mixture. Likewise, the use of methyl 12-hydroxystearate will form 12-hydroxystearic acid to be used as a complex acid by reaction with water present in the mixture. Alternatively, if sufficient water is not present in the mixture, additional water may be added to the mixture to react with such components to form the necessary complex acid.

If boric acid is used as the complex acid according to this embodiment, an amount of 0.4% to about 4.0%, preferably 0.7% to 3.0%, and most preferably 1.0% to 2.5% is added based on the final weight of the grease. The boric acid may be added first after dissolution or slurrying in water, or may be added without water. Preferably, boric acid is added during the manufacturing process so that water is still present. Alternatively, any well-known inorganic borate may be used instead of boric acid. Likewise, 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, borated peroxides, and the like may be used in place of boric acid. If phosphoric acid is used as the complex acid, an amount of 0.4% to about 4.0%, preferably 1.0% to 3.0%, and most preferably 1.4% to 2.0% is added based on the final weight of the grease. The percentages of the various complex acids described herein refer to the pure active compound. If any of these complex acids are available in diluted form, they may still be suitable for use in the present invention. However, the percentage of such diluted complex acid needs to be adjusted to take into account the dilution factor and bring the actual active substance to the specified percentage range.

Other additives commonly recognized in the art of grease manufacture may also be added to either the simple grease embodiment or the complex grease embodiment of the present invention. Such additives may include rust and corrosion inhibitors, metal deactivators, antioxidants, extreme pressure additives, antiwear additives, chelating agents, polymers, tackifiers, dyes, chemical markers, fragrance imparting agents, and evaporative solvents. The latter category is particularly useful in the manufacture of open gear lubricants and braided wire rope lubricants. The inclusion of any such additives is understood to be within the scope of the present invention.

Preferably, the calcium sulfonate grease composition is prepared according to the inventive process described herein. All percentages are based on the final weight of the finished grease unless otherwise indicated. A preferred method of preparing a simple grease or complex grease comprises mixing water, less than 30% overbased calcium sulfonate with dispersed amorphous calcium carbonate (for complex greases) or 30% to 70% overbased calcium sulfonate with dispersed amorphous calcium carbonate (for simple greases) and optionally a base oil to form a first mixture; adding at least a portion of the one or more non-aqueous conversion agents to the first mixture after the one or more delay periods to form a pre-conversion mixture; and converting the pre-conversion mixture into a converted mixture by heating until conversion of amorphous calcium carbonate contained in the overbased calcium sulfonate into crystalline calcium carbonate occurs.

Another preferred method of preparing a simple or complex grease comprises mixing water, less than 45% of an overbased calcium sulfonate containing dispersed amorphous calcium carbonate (for complex greases) or 30% to 70% of an overbased calcium sulfonate containing dispersed amorphous calcium carbonate (for simple greases) and optionally a base oil to form a first mixture; adding at least a portion of the one or more non-aqueous conversion agents to the first mixture after or during the one or more delay periods to form a pre-conversion mixture; converting the pre-conversion mixture into a converted mixture by heating until conversion of amorphous calcium carbonate contained in the overbased calcium sulfonate into crystalline calcium carbonate occurs, wherein at least one delay period is a hold delay period, wherein the first mixture or the pre-conversion mixture is held at a temperature or within a temperature range for a period of time.

Another preferred method of preparing a simple or complex grease comprises mixing water, less than 22% overbased calcium sulfonate with dispersed amorphous calcium carbonate (for complex greases) or 30% to 70% overbased calcium sulfonate with dispersed amorphous calcium carbonate (for simple greases) and optionally a base oil to form a first mixture; adding at least a portion of the one or more non-aqueous conversion agents to the first mixture after or during the one or more delay periods to form a pre-conversion mixture; the pre-conversion mixture is converted into a converted mixture by heating until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate into crystalline calcium carbonate occurs.

Another preferred method of making a simple grease comprises the steps of: (1) the following ingredients were mixed in a suitable grease manufacturing vessel: water as a converting agent, an overbased oil-soluble calcium sulfonate containing dispersed amorphous calcium carbonate, optionally an appropriate amount of a suitable base oil (if desired), and optionally at least a portion of one or more non-aqueous converting agents to form a first mixture; (2) mixing or agitating the first mixture while maintaining it at a temperature or temperature range and/or adjusting the temperature of the first mixture to heat or cool it to another temperature or temperatures or temperature ranges during one or more delay periods; (3) mixing at least a portion of the one or more non-aqueous conversion agents with the first mixture, optionally after or during one or more delay periods, to form a second mixture; (4) heating the first mixture (or the second mixture if a non-aqueous converting agent is added in step 3) to a conversion temperature (preferably 190F to 230F, above the typical range of 190F to 220F for an open vessel) to form a third mixture during the end of the one or more delay periods; (5) mixing all or any remaining portion (if any) of the one or more non-aqueous conversion agents after step 4 or during step 4; and (6) converting the third mixture by continuing the mixing while maintaining the temperature in the conversion temperature range (preferably 190F to 230F) until the conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate into very finely divided crystalline calcium carbonate is completed. This process produces the preferred simple calcium sulfonate grease. The preferred process also optionally includes the steps of (7) mixing the added calcium carbonate and/or (8) mixing a facilitator acid. Step (7) may be performed at any time before the transformation, after the transformation or one part may be added before the transformation and another part may be added after the transformation. Step (8) may be performed at any time prior to the conversion. Most preferably, the process is carried out in an open vessel, but may also be carried out in a pressurized vessel.

A preferred method of manufacturing a complex grease according to the present invention comprises the steps of: (1) the following ingredients were mixed in a suitable grease manufacturing vessel: 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 desired), and optionally at least a portion of one or more non-aqueous converting agents to form a first mixture; (2) mixing or agitating the first mixture while maintaining it at a temperature or temperature range and/or adjusting the temperature of the first mixture to heat or cool it to another one or more temperatures or temperature ranges during one or more delay periods; (3) mixing at least a portion of the one or more non-aqueous conversion agents with the first mixture, optionally after or during one or more delay periods, to form a second mixture; (4) heating the first mixture (or the second mixture if a non-aqueous converting agent is added in step 3) to a conversion temperature (preferably 190F to 230F, above the typical range of 190F to 220F for an open vessel) to form a third mixture during the end of the one or more delay periods; (5) mixing all or any remaining portion (if any) of the one or more non-aqueous conversion agents after step 4 or during step 4; and (6) converting the third mixture by continuing the mixing while maintaining the temperature in the conversion temperature range (preferably 190F to 230F) until the conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate into very finely divided crystalline calcium carbonate is completed; (7) mixing one or more calcium-containing bases; (8) optionally mixing a facilitator acid; and (9) mixing one or more suitable complex acids. This process produces the preferred complex calcium sulfonate grease. Step (7) may be performed before or after the conversion, or some part or all of the one or more calcium-containing bases may be added before the conversion, and some part or all of the one or more calcium-containing bases may be added after the conversion. Step (8) may be performed at any time prior to the conversion. Step (9) may be performed before or after the conversion, or some part or all of the one or more complex acids may be added before the conversion, and some part or all of the one or more complex acids may be added after the conversion. Most preferably, the process is carried out in an open vessel, but may also be carried out in a pressurized vessel.

According to several other embodiments, the method of manufacturing the complex grease is the same as described above, except that step (7) involves one of: (a) mixing finely divided calcium hydroxyapatite as the only added calcium containing base prior to conversion; (b) according to one embodiment, finely divided calcium hydroxyapatite and calcium carbonate are mixed in amounts sufficient to react and neutralize well with the subsequently added complex acid; (c) mixing finely divided calcium hydroxyapatite and calcium hydroxide and/or calcium oxide in an amount sufficient to fully react with and neutralize a subsequently added complex acid, wherein according to another embodiment of the invention the calcium hydroxide and/or calcium oxide is preferably present in an amount of no more than 75% of the hydroxide equivalent alkalinity provided by the total amount of calcium hydroxide and/or calcium oxide and calcium hydroxyapatite added; (d) according to another embodiment of the invention, the added calcium carbonate is mixed after conversion; or (e) according to yet another embodiment of the invention, calcium hydroxyapatite is mixed after conversion and in an amount sufficient to fully react with and neutralize any complex acid added after conversion. According to another embodiment, the process for preparing a complex grease is the same as described above except that the finely divided calcium carbonate is added as an oil-insoluble solid calcium-containing base prior to (before or during step 6) and step (7) comprises mixing finely divided calcium hydroxide and/or calcium oxide in an amount insufficient to fully react and neutralize subsequently added complex acid, wherein the calcium hydroxide and/or calcium oxide is preferably present in an amount of no more than 75% of the hydroxide equivalent alkalinity provided by the total amount of calcium hydroxide and/or calcium oxide and calcium hydroxyapatite added, wherein the amount of calcium carbonate added previously is sufficient to fully react and neutralize the portion of any subsequently added complex acid that is not neutralized by the calcium hydroxide and/or calcium oxide.

Another preferred method of manufacturing a complex grease according to the present invention comprises the steps of: highly overbased oil-soluble calcium sulfonates containing dispersed amorphous calcium carbonate and an amount of a suitable base oil (if desired) are mixed in a suitable grease manufacturing vessel and the mixing is initiated. Then, one or more facilitator acids are added and mixed, preferably for about 20-30 minutes. Then, all calcium hydroxyapatite, then a portion of calcium hydroxide, then all calcium carbonate is added and mixed for an additional 20-30 minutes. Next, a portion of the acetic acid and a portion of the 12-hydroxystearic acid were added and mixed for an additional 20-30 minutes (note that these ingredients may be converting agents, but because they were added before the water, there was no lag phase). Then, water was added as a converting agent and mixed while heating to a temperature of 190 ° F to 230 ° F (first temperature adjustment delay period and final delay period). Then, all of the hexylene glycol was added as a non-aqueous conversion agent. The mixture is converted by continuing the mixing while maintaining the temperature in the conversion temperature range, preferably 190F to 230F, until the conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to very finely divided crystalline calcium carbonate is completed. After conversion, the remaining calcium hydroxide is added and mixed for about 20-30 minutes. Then, the remaining acetic acid and the remaining 12-hydroxystearic acid were added and mixed for about 30 minutes. Boric acid dispersed in water is then added followed by slow gradual addition of phosphoric acid. The mixture was then heated to remove water and volatiles, cooled, more base oil was added as needed, and the grease was ground as described below. Additional additives may be added during the final heating or cooling step. According to another preferred method of preparing a complex grease, the steps and ingredients are the same as outlined above, except that after the addition of water as the converting agent and before the addition of all of the hexanediol as the non-aqueous converting agent, the mixture is heated to about 160 ° F (first temperature adjusted delay period) and the temperature is maintained for about 30 minutes (first hold delay period) before continuing to heat to 190 ° F to 230 ° F (second temperature adjusted delay period and final delay period).

For simple and complex grease embodiments according to the present invention, any portion of the non-aqueous converting agent added in step 1, 3 and/or 5 may be the same non-aqueous converting agent added in another step or steps, or any non-aqueous converting agent different from that added in another step or steps. Provided that at least a portion of the at least one non-aqueous converting agent is added after the 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. According to another preferred embodiment for a simple grease or a complex grease, all of the non-aqueous converting agent or agents are mixed after the final delay period in step 5 without adding any non-aqueous converting agent during step 1 or 3. According to another preferred embodiment for a simple grease or a complex grease, at least part of the one or more non-aqueous converting agents is added together with the first mixture in step 1 and at least part of the same or different non-aqueous converting agents is added in step 3 and/or step 5 before any delay. According to another preferred embodiment for a simple grease or a complex grease, no non-aqueous converting agent is added with the first mixture and at least a portion of the one or more non-aqueous converting agents is added in step 3 and step 5. According to another preferred embodiment for a simple grease or a complex grease, at least part of one or more non-aqueous converting agents is added in step 3 after or during one delay period and at least part of the same or different non-aqueous converting agents is added after or during another delay period (second delay period in step 3 and/or final delay period in step 5). According to another preferred embodiment for a simple grease or a complex grease, at least a portion of the one or more non-aqueous converting agents is added after one or more delays in step 3, but no non-aqueous converting agent is added after the last delay period in step 5.

Most preferably, the method of manufacturing a complex and simple grease further comprises the steps of: (a) mixing and heating to a sufficiently high temperature to ensure removal of water and any volatile reaction by-products and to optimize final product quality; (b) cooling the grease as required while adding additional base oil; (c) adding the remaining desired additives as known in the art; and if desired, (d) grinding the final grease as necessary to obtain a final smooth homogeneous product. Although the order and timing of these steps is not critical, it is preferred to remove water quickly after conversion. Typically, the grease is heated (preferably under open conditions, rather than pressure, although pressure may be used) to 250F to 300F, preferably 300F to 380F, most preferably 380F to 400F to remove the water initially added as the conversion agent, as well as any water formed by chemical reaction during formation of the grease. The presence of water in the grease batch for extended periods of time during the manufacturing process may result in a reduction in thickener yield, drop point, or both, and this adverse effect can be avoided by removing the water rapidly. If the polymer additives are added to the grease, they are preferably not added until the grease temperature reaches 300F. The addition of polymeric additives, if present in sufficient concentration, can hinder the effective volatilization of water. Thus, the polymer additive should preferably only be added to the grease after all water has been removed. If it can be determined during manufacture that all of the water has been removed before the temperature of the grease reaches the preferred 300F value, it may be preferable to add any polymer additive at any time thereafter.

According to another preferred embodiment for use with a simple or complex grease process, the one or more delay periods (the time between the pre-conversion addition of water and the addition of at least a portion of the non-aqueous conversion agent) is a temperature regulation delay period or a holding delay period or both. The delay period may include a plurality of temperature adjustment delay periods and a plurality of hold delay periods. For example, the first temperature adjustment delay period is a period of time taken to adjust the temperature of the mixture to a certain temperature or temperature range (first temperature) after adding water. The first holding delay period is the amount of time the mixture is held at the first temperature. The second temperature adjustment delay period is the period of time it takes to heat the mixture to another temperature or temperature range (the second temperature) after the first hold delay. The second hold delay period is the amount of time the mixture is held at the second temperature. The additional temperature adjustment delay period or the hold delay period (i.e., the third temperature adjustment delay period) follows the same pattern. The first temperature may be an ambient temperature (in which case there is no first temperature adjustment delay period). Any subsequent temperature may be higher or lower than the previous temperature. The final pre-conversion temperature will preferably be in the range of about 190F to 220F or up to 230F, as is the temperature at which conversion typically occurs in an open kettle.

If the non-aqueous converting agent or portion thereof is added immediately after a certain temperature or temperature range is reached, no delay period is maintained for that particular temperature. All or a portion of one or more non-aqueous conversion agents may be added after any temperature-adjusted delay period or holding delay period, and another portion of the same or all or a portion of a different non-aqueous conversion agent may be added after another temperature-adjusted delay period or holding delay period. Most preferably, the temperature moderated delay period immediately after the addition of the non-aqueous converting agent to the mixture will be the last temperature moderated delay period (and the last delay period) associated with that particular non-aqueous converting agent, but the mixture may be heated to another temperature or temperature range, and additional non-aqueous converting agent(s) added to create additional temperature moderated delay periods and possibly additional holding delay periods.

In a preferred embodiment, at least a portion of the one or more non-aqueous conversion agents is added at the end of the last of the one or more lag periods, and another portion of the same and/or different non-aqueous conversion agents is added after one or more previous lag periods. According to another preferred embodiment, all of the non-aqueous converting agent or agents are added at the end of the last of the one or more delay periods. According to another preferred embodiment, at least one part of the non-aqueous converting agent or agents is added at about the same time as the addition of water (without a delay period) and another part of the same and/or different non-aqueous converting agent is added after one or more previous delay periods. According to yet another preferred embodiment, the at least one non-aqueous conversion agent or a portion thereof is slowly added in a substantially continuous manner or in discrete incremental amounts during the temperature adjustment delay, the holding delay, or both.

Although a delay period within the scope of the present invention may involve a hold delay period that does not involve heating (see example 15 below, where the mixture is held at ambient temperature for a first hold delay period before heating to the conversion temperature range during the second temperature adjustment delay period), the short period of time of less than 15 minutes between the addition of water as the conversion agent and the addition of all of the one or more non-aqueous conversion agents without any heating during this period of time is not a "delay" or "delay period" as used herein. For the purposes of the present invention, the delay in adding any or all of the one or more non-aqueous conversion agents without heating during the delay period should be at least about 20 minutes and more preferably at least about 30 minutes. The interval between the addition of water and a portion of the non-aqueous conversion agent is less than 20 minutes, with no heating during 20 minutes, but a subsequent longer hold delay period or subsequent heating prior to the addition of another portion of the same, or a portion or all of a different one or more non-aqueous conversion agents does relate to a "delay period" within the scope of the present invention. In this case, the initial short time interval is not a "lag period," but the subsequent longer hold delay or temperature adjustment delay prior to addition of the non-aqueous conversion agent is a hold lag period or temperature adjustment lag period for purposes of the present invention. Further, all or some portion of the one or more non-aqueous conversion agents may be slowly added during the one or more temperature adjustment delay periods or the hold delay period, or both. Such slow addition may include substantially continuous addition of the non-aqueous conversion agent during one or more delay periods or repeated, incremental addition during one or more delay periods.

Furthermore, when acetic acid or 12-hydroxystearic acid is added prior to conversion, these acidic acids will have a dual role as converting agent and complexing acid. When these acids are added with another more active non-aqueous converting agent (e.g., a glycol), it is believed that the acid acts primarily as a complex acid, with the more active agent taking on the primary role of the converting agent. Thus, when acetic acid or 12-hydroxystearic acid is added with a more reactive conversion agent prior to conversion, any elapsed time between the addition of water and any portion of the acetic acid or 12-hydroxystearic acid is not considered a delay in the term as used herein. In that case, only the temperature regulation delay period or hold delay period between the pre-conversion addition of water and the pre-conversion addition of any portion of other non-aqueous conversion agent is considered a delay for purposes of the present invention. If acetic acid or 12-hydroxystearic acid or a combination thereof is the only non-aqueous converting agent or agents used, the temperature adjustment delay period or hold delay period between the addition of water prior to conversion and the addition of any portion of acetic acid or 12-hydroxystearic acid prior to conversion is a delay for purposes of the present invention.

The sequence of steps (2) - (6) for both simple and complex greases in which there is a delayed addition of at least a portion of the non-aqueous converting agent or agents relative to the addition of water as the converting agent (with or without intermediate temperature regulation) is an important aspect of the present invention. Certain other aspects of the method are not critical to obtaining a preferred calcium sulfonate grease composition according to the present invention. For example, the order in which the calcium-containing bases are added relative to each other is not critical. Furthermore, the temperature at which the water and the calcium-containing base are added as converting agents is not critical, but it is preferred to add them before the temperature reaches 190F to 200F. When more than one complex acid is used, the order in which they are added before or after conversion is also generally not critical. These processes may occur in open or closed tanks commonly used in grease production. The conversion process can be accomplished at atmospheric pressure or pressure in a closed kettle. Manufacture in an open kettle (vessel not under pressure) is preferred as such grease manufacturing equipment is generally available. For the purposes of this invention, an open container is any container with or without a cover or hatch, provided that any such cover or hatch is not gas tight and therefore does not generate significant pressure during heating. The use of such an open vessel closed by a cover or hatch during the conversion process will help to maintain the necessary amount of water as the conversion agent, while generally allowing the conversion temperature to be at or even above the boiling point of water. As understood by those of ordinary skill in the art, such higher conversion temperatures may result in further thickener yield improvements for both simple and complex calcium sulfonate greases. Manufacture in autoclave may also be used and may result in even greater improvement in thickener yield, but the pressurization process may be more complex and difficult to control. Furthermore, the production of calcium sulfonate grease in an autoclave can lead to productivity issues. The use of pressurized reactions is important for certain types of greases (e.g., polyurea greases), and most grease sets have only a limited number of autoclaves available. The use of autoclaves to make calcium sulfonate greases (where the autoclave reaction is less important) may limit the ability of the apparatus to make other greases in those situations where the reaction is important. An open container avoids these problems.

Examples 1-18 in the '574 application and 1-29 in the' 768 application are incorporated herein by reference. The overbased calcium sulfonate grease compositions and methods for preparing such compositions according to the present invention are further described and explained with respect to the following examples:

example 1: a calcium sulfonate complex grease of composition according to the invention was carried out as follows, but without a delay period between the addition of water and the non-aqueous converting agent: 264.61g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 327.55g of a neutral group 1 paraffinic base oil (paraffinic base oil, paraffinic hydrocarbon base oil) having a viscosity of about 600SUS at 100F in solvent, and 11.70g of PAO having a viscosity of 4cSt at 100C. Similar to that used in examples 10 and 11 of the above and' 768 applications, the 400TBN overbased oil-soluble calcium sulfonate is a poor quality calcium sulfonate. Mixing was started without heating using a planetary stirring paddle. Then, 23.94g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.65g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.63g of food grade pure calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. The amount of calcium hydroxide added as a separate component is in addition to the amount of residual calcium hydroxide contained in the overbased calcium sulfonate. Then, 0.88g of glacial acetic acid and 10.53g of 12-hydroxystearic acid were added and mixed for 10 minutes. Then, 55.03g of finely divided calcium carbonate having an average particle size of about 1 to 5 microns was added and allowed to mix for 5 minutes. The amount of calcium carbonate added as a separate component is in addition to the amount of dispersed calcium carbonate contained in the overbased calcium sulfonate. Then, 13.20g of hexanediol (non-aqueous conversion agent) and 38.22g of water were added at essentially the same time (no delay period). The mixture was heated until the temperature reached 190F. The temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. An additional 56.07g of the same paraffin-based base oil was added due to the weight of the converted grease. Then, 7.36g of the same calcium hydroxide was added and allowed to mix for 10 minutes. Then, 1.52g of glacial acetic acid was added, followed by 27.30g of 12-hydroxystearic acid. When these acids reacted and allowed the grease to further thicken, 111.07g of paraffin-based base oil was added. Then, 9.28g of boric acid was mixed in 50g of hot water, and the mixture was added to the grease. An additional 54.47g of paraffin-based base oil was added, followed by 17.92g of a 75% aqueous solution of phosphoric acid. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.22g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.01g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 4.43g of polyisobutylene polymer was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease has a working 60stroke penetration of 287. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 23.9%. Drop point > 650F. In this example, calcium hydroxyapatite and calcium carbonate were added prior to conversion according to an embodiment of the' 768 application. In addition, 33% of the total amount of calcium hydroxide was added before the conversion, followed by 35% of the total amount of glacial acetic acid and 28% of the total amount of 12-hydroxystearic acid. And adding the rest of calcium hydroxide, glacial acetic acid and 12-hydroxystearic acid after conversion.

Example 2: another calcium sulfonate complex grease was prepared using the same equipment, raw materials, amounts, and manufacturing method as the grease of example 1, except that there was a delay in adding the non-aqueous conversion agent (hexylene glycol). The other initial ingredients (including water) were mixed and heated to a temperature of about 190 ° F (first temperature adjustment delay period) and held at that temperature for 1 hour (first hold delay period) prior to addition of the hexanediol. When hexanediol was added, the conversion occurred almost instantaneously. The grease was held at 190F-200F for an additional 45 minutes. The remaining procedure was then the same as for the grease of example 1 above. The grease had a working 60stroke penetration of 261. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 21.1%. Drop point > 650F. It can be seen that the grease of this example has improved thickener yield as compared to the grease of the previous example 1, as evidenced by the lower final percentage of overbased calcium sulfonate compared to the working penetration. Indeed, using a linear dilution relationship of the working penetration to the percentage of overbased calcium sulfonate in the final grease, the predicted percentage of overbased calcium sulfonate in the example 2 grease would be 19.2% if diluted with sufficient base oil to obtain the same working penetration of the example 1 grease.

Example 3: another calcium complex grease was prepared using the same equipment, raw materials, amounts and manufacturing method as the grease of example 1 except that there was a delay in adding the non-aqueous converting agent (hexylene glycol). The other initial ingredients (including water) were mixed and heated to a temperature of about 190 ° F (first temperature adjustment delay period), but unlike example 2, hexanediol was added immediately upon reaching 190 ° F (no hold delay period). When hexanediol was added, the conversion occurred rapidly. The grease was held at 190F-200F for an additional 45 minutes. The remaining procedure was then the same as for the grease of example 1 above. The final grease had a working 60stroke penetration of 290. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 21.4%. Drop point > 650F. It can be seen that the grease of this example has improved thickener yield as compared to the grease of the previous example 1, as evidenced by the lower final percentage of overbased calcium sulfonate compared to the working penetration.

Example 4: another calcium sulfonate complex grease of composition according to the invention was carried out as follows, but without a delay period between the addition of water and the non-aqueous converting agent: 311.67g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 451.37g of solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 10.30g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 12 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then 31.48g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 7.56g of finely divided calcium carbonate having an average particle size of about 1 to 5 microns (except for the amount of dispersed calcium carbonate contained in the overbased calcium sulfonate) was added and allowed to mix for 20 minutes. Then, 4.90g of 12-hydroxystearic acid was added followed by 15.50g of hexanediol (non-aqueous conversion agent) and 40.75g of water (added substantially simultaneously with the hexanediol-without a lag phase). The mixture was heated until the temperature reached 190F. An additional 67.60g of calcium carbonate was then added. The temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. An additional 5.00g of water was added followed by 19.60g of 12-hydroxystearic acid, 2.40g of glacial acetic acid and 16.64g of a 75% aqueous solution of phosphoric acid. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 27.85g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 250F, an additional 32.75g of paraffin-based base oil was added. Then, 5.05g of a polyisobutylene polymer was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 271. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 31.0%. The dropping point was 629F. In this example, the added calcium carbonate was added prior to conversion according to the embodiment of the' 574 application. Furthermore, 20% of the total amount of 12-hydroxystearic acid was added before conversion. The remaining amount of 12-hydroxystearic acid was added after conversion.

Example 5: another calcium complex grease was prepared using the same equipment, raw materials, amounts and manufacturing method as the grease of example 4, except that there was a delay in adding the non-aqueous converting agent (hexylene glycol). The other initial ingredients (including water) were mixed and heated to a temperature of about 190 ° F (first temperature adjustment delay period) and held at that temperature for 1 hour (first hold delay period) prior to addition of the hexanediol. When hexanediol was added, visible conversion began to occur almost instantaneously. After the conversion appeared to be complete, the grease was held at 190F-200F for an additional 45 minutes. The remaining procedure was then the same as for the grease of example 4 above. The final grease had a working 60stroke penetration of 265. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 29.2%. Drop point > 650F. It can be seen that the grease of this example has improved thickener yield as compared to the grease of previous example 4, as evidenced by the lower final percentage of overbased calcium sulfonate compared to the working penetration.

Example 6: another calcium sulfonate complex grease was prepared using similar compositions and methods as in U.S. Pat. nos. 5,308,514 and 5,338,467 (issued to Witco, 5/3, 1994 and 8/16, 1994, respectively), wherein at least a portion of the long chain fatty acids were added prior to transformation and may act as a transforming agent. Specifically, 54.1% of the total amount of 12-hydroxystearic acid and total glacial acetic acid were added prior to conversion. After conversion the remaining amount of 12-hydroxystearic acid was added followed by the calcium hydroxide and boric acid water mixture. According to the scope of the' 514 patent, added calcium hydroxide is used as the only added base to react with the complex acid and no calcium hydroxyapatite or added calcium carbonate is used. In example 6 the addition of the non-aqueous conversion agent was not delayed.

The grease of example 6 was prepared as follows: 380.26g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 603.6g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 12 of the' 768 application. Then, 21.75g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 21.56g of 12-hydroxystearic acid was added, followed by 18.12g of hexylene glycol (non-aqueous conversion agent) and 38.45g of water (added substantially simultaneously with the hexylene glycol). After mixing for 10 minutes, 2.46g of glacial acetic acid were added. The batch was then heated with continued mixing until the temperature reached 190F. The temperature was maintained between 190F and 200F for 45 minutes. Then, an additional 2.03g of acetic acid was added and the batch was mixed until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. An additional 248.29g of paraffin-based base oil was added followed by 18.29g of 12-hydroxystearic acid. It was allowed to remain mixed for 15 minutes while maintaining the temperature at 190F to 200F. Then, 38.23g of finely divided food grade pure added calcium hydroxide (except for any residual calcium hydroxide contained in the overbased calcium sulfonate) having an average particle size of about 1 to 5 microns was mixed with 50g of water and the mixture was added to the grease. Then, 23.12g of boric acid was mixed with 50ml of hot water, and the mixture was added to the grease. The grease was then heated to 390F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture.

The grease of example 6 had a working 60stroke penetration of 320. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 27.6%. In this example, all of the hexanediol converting agent was added with water, then a portion of the acetic acid was added prior to any heating, and a portion was added after heating to 190 ° F for 45 minutes. Neither of the two additions of acetic acid involved "delay" because there was another non-aqueous converting agent (hexylene glycol) used, and the 10 minute mixing interval without heating was not considered delay. According to the practice of the prior art, all of the hexanediol (which is the primary converting agent) and hydroxystearic acid added prior to conversion are added together with water. Thus, this example does not involve any "delay" and results in higher than desired percentage of overbased calcium sulfonate. Based on this example, when there is no delay for the other non-aqueous converting agent, the time lapse does not contribute to reducing the amount of overbased calcium sulfonate to the desired level upon addition of at least a portion of the acetic acid, which is why such addition is not considered to be "delayed" for the purposes of the present invention.

Example 6A: another grease was prepared almost exactly the same as the grease of the previous example 6. The only difference was that no additional glacial acetic acid was added once 190F was reached during the initial heating. The grease had a working 60stroke penetration of 339. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 27.6%. These results are similar to example 6 and further show that the time interval between the addition of water and the addition of acetic acid is not a "delay" in the yield increase of the thickener when another non-aqueous conversion agent is used.

Example 7: another calcium complex grease was prepared using the same equipment, raw materials, amounts and manufacturing method as the grease of example 6, except that there was a delay in adding the non-aqueous converting agent (hexylene glycol). The other initial ingredients, including water and acetic acid, were mixed and heated to a temperature of about 190 ° F (first temperature adjustment delay period) and held at that temperature for 1 hour (first hold delay period) prior to addition of the hexanediol. When hexanediol was added, the grease remained between 190F and 200F until the conversion appeared to be complete. The remaining procedure was then the same as for the grease of example 6 above. The final grease had a working 60stroke penetration of 281. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 27.6%. Drop point > 650F. It can be seen that the grease of this example has improved thickener yield as compared to the grease of the previous example 6, as evidenced by the stronger penetration despite having substantially the same percentage of overbased oil-soluble calcium sulfonate. Indeed, using a linear dilution relationship of the working penetration to the percentage of overbased calcium sulfonate in the final grease, the predicted percentage of overbased calcium sulfonate in the grease of example 7 would be 24.2% if diluted with sufficient base oil to obtain the same working penetration of the grease of example 6. This example shows better results than examples 6 and 6A, with the only change being the delayed addition of the non-aqueous conversion agent hexanediol.

Table 1 below summarizes the results and methods used in examples 1-7 herein. The amount of overbased calcium sulfonate shown in parentheses is the amount of overbased calcium sulfonate estimated when additional base oil was added to dilute the sample grease to achieve the same penetration as the example number shown after the dash and as described above. Together, these first seven examples strongly demonstrate the improvement of thickener yield by delaying the addition of non-aqueous converting agent. In addition, thickener yield is increased by delayed addition of (1) both poor and good quality overbased calcium sulfonates, and (2) using typical prior art calcium-containing bases (e.g., calcium hydroxide) for reaction with complex acids and using added calcium carbonate or calcium hydroxyapatite for reaction with complex acids. Complex greases also exhibit excellent drop points.

TABLE 1 Complex overbased calcium sulfonate greases

The following examples further demonstrate the superior performance of the overbased calcium sulfonate greases of the present invention, which may be achieved by the delayed addition of a non-aqueous converting agent and which have different delay periods and temperature ranges for the duration of each delay period.

Example 8: according to one embodiment of the' 768 application, another calcium sulfonate complex grease was prepared using calcium hydroxyapatite, added calcium carbonate, and added calcium hydroxide as a calcium containing base to react with a complex acid. This example is a baseline for comparison with examples 9-17, since there is no delay in adding the non-aqueous conversion agent (hexylene glycol) in this example.

The grease of example 8 was prepared as follows: 264.98g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 378.68g of solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 11.10g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a poor quality calcium sulfonate similar to that described above and used in examples 10 and 11 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then, 23.96g of predominantly C12 alkylbenzene sulfonic acid were added. After 20 minutes of mixing, 50.62g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.68g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. Then, 0.84g of glacial acetic acid and 10.56g of 12-hydroxystearic acid were added and mixed for 10 minutes. 55.05g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns were then added and allowed to mix for 5 minutes. Then, 13.34g of hexanediol and 39.27g of water were added (without delay). The mixture was heated until the temperature reached 190F. The temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. Then, 7.34g of the same added calcium hydroxide was added and allowed to mix for 10 minutes. Then, 1.59g of glacial acetic acid was added, followed by 27.22g of 12-hydroxystearic acid. After the 12-hydroxystearic acid was melted and mixed into the grease, 9.37g of boric acid was then mixed in 50g of hot water and the mixture was added to the grease. An additional 62.29g of the same paraffin-based base oil was added due to the weight of the grease. Then, 17.99g of a 75% phosphoric acid aqueous solution was added and mixed and reacted. An additional 46.90g of paraffin-based base oil was added. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.17g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.30g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.27g of the arylamine antioxidant and 4.46g of the polyisobutylene polymer were added. An additional 55.77g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 281. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 24.01%. The drop point was > 650F.

Example 9: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous example 8. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to about 190F to 200F (first temperature adjustment delay period) and held at that temperature for 30 minutes (first hold delay period). Grease was prepared as follows: 264.04g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 378.21g of a neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 11.15g of PAO having a viscosity of 4cSt at 100C. The 400TBN overbased oil-soluble calcium sulfonate is a poor quality calcium sulfonate similar to that described above and used in examples 10 and 11 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then, 23.91g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.60g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.61g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. Then, 0.83g of glacial acetic acid and 10.56g of 12-hydroxystearic acid were added and mixed for 10 minutes. 55.05g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns were then added and allowed to mix for 5 minutes. Then, 38.18g of water was added. The mixture was heated until the temperature reached 190F (first temperature adjustment delay period). The temperature was maintained at 190F to 200F for 30 minutes (first hold delay period). Then, 13.31g of hexanediol was added. The temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. An additional 16ml of water was added to replace the water lost by evaporation. Then, 7.39g of the same added calcium hydroxide was added and allowed to mix for 10 minutes. Then, 1.65g of glacial acetic acid was added, followed by 27.22g of 12-hydroxystearic acid. After the 12-hydroxystearic acid was melted and mixed into the grease, an additional 54.58g of the same paraffin-based base oil was added as the grease became heavier. Then, 9.36g of boric acid was mixed in 50g of hot water, and the mixture was added to the grease. An additional 59.05g of the same paraffin-based base oil was added due to the weight of the grease. Then, 18.50% of a 75% phosphoric acid aqueous solution was added and mixed and reacted. An additional 52.79g of paraffin-based base oil was added. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.25g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.15g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.29g of the arylamine antioxidant and 4.79g of the polyisobutylene polymer were added. An additional 108.11g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 272. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 21.78%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Example 10: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous examples 8 and 9. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to about 190F to 200F (first temperature adjustment delay period) and held at that temperature for 2 hours (first hold delay period). Grease was prepared as follows: 264.35g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 377.10g of a neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 11.02g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a poor quality calcium sulfonate similar to that described above and used in examples 10 and 11 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then, 24.00g of mainly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.66g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.76g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. Then, 0.91g of glacial acetic acid and 10.60g of 12-hydroxystearic acid were added and mixed for 10 minutes. 55.05g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns were then added and allowed to mix for 5 minutes. Then, 38.50g of water was added. The mixture was heated until the temperature reached 190F (first temperature adjustment delay period). The temperature was maintained at 190F to 200F for 2 hours (first hold delay period). Then, 13.57g of hexanediol was added. An additional 15ml of water was also added because some of the initially added water had evaporated during the two hours of heating. It should be noted that in this embodiment, to compensate for evaporation losses (and in all other embodiments where this occurs), this added water does not restart a new lag period, as it simply replaces some of the originally added water. Once visible conversion has begun, the temperature is maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicates that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) has occurred. An additional 35ml of water was added. Then, 7.27g of the same calcium hydroxide was added and allowed to mix for 15 minutes. Then, 1.59g of glacial acetic acid was added, followed by 27.25g of 12-hydroxystearic acid. Then, 9.36g of boric acid was mixed in 50g of hot water, and the mixture was added to the grease. An additional 55.79g of the same paraffin-based base oil was added due to the weight of the grease. Then, 18.15% of a 75% phosphoric acid aqueous solution was added and mixed and reacted. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.08g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.08g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.44g of the arylamine antioxidant and 4.52g of the polyisobutylene polymer were added. An additional 216.00g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 285. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 21.87%. Drop point > 650F. It can be seen that this grease has an improved thickener yield compared to the grease of example 8 and is similar to the grease of example 9.

Example 11: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous examples 8-10. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to about 190F to 200F (first temperature adjustment delay period) and held at that temperature for 30 minutes (first hold delay period), then cooled to 160F (second temperature adjustment delay period), and held at 160F to 170F for two hours (second hold delay period), then returned to heating up to 190F (third temperature adjustment delay period), and immediately added hexylene glycol when 190F was reached (without third hold delay period).

The grease of example 11 was prepared as follows: 264.09g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 380.83g of solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 11.22g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a poor quality calcium sulfonate similar to that described above and used in examples 10 and 11 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then, 23.97g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.59g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.73g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. 0.82g of glacial acetic acid and 10.57g of 12-hydroxystearic acid were then added and mixed for 10 minutes. Then, 55.03g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns was added and allowed to mix for 5 minutes. Then 38.11g of water were added. The mixture was heated until the temperature reached 190F (first temperature adjustment delay period). The temperature was maintained at 190F to 200F for 30 minutes (first hold delay period). Then, the temperature was lowered to 160F (second temperature adjustment delay period), and the temperature was maintained at 160F to 170F for two hours (second incubation delay period). During this time, an additional 15ml of water was added, as some of the initially added water had evaporated. As already mentioned, to compensate for evaporation losses, the water added before the subsequent conversion is not used to determine the lag phase, only the first addition of water being used. Then, the temperature was increased to 190F (third temperature adjustment delay period). An additional 20ml of water was added. Immediately thereafter, 13.20g of hexylene glycol was added (without a third hold delay period). Once visible conversion has begun, the temperature is maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicates that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) has occurred. Due to the amount of thickening that has occurred, an additional 54.53g of the same paraffin-based base oil was added and mixed. Then, 7.27g of the same calcium hydroxide was added and allowed to mix for 15 minutes. Then, 1.60g of glacial acetic acid was added, followed by 27.23g of 12-hydroxystearic acid. After 5 minutes, 9.38g of boric acid were mixed in 50g of hot water and the mixture was added to the grease. An additional 55.41g of the same paraffin-based base oil was added due to the weight of the grease. Then, 18.10% of a 75% phosphoric acid aqueous solution was added and mixed and reacted. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.25g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.06g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.51g of the arylamine antioxidant and 5.43g of the polyisobutylene polymer were added. An additional 135.25g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 278. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 22.27%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Example 12: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous examples 8-11. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to 160F (first temperature adjustment delay period) and held at 160F to 170F for two hours 30 minutes (first hold delay period), then heated up to 190F (second temperature adjustment delay period), and immediately added hexylene glycol upon reaching 190F (without second hold delay period).

The grease of example 12 was prepared as follows: 264.48g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 382.94g of solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 11.18g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a poor quality calcium sulfonate similar to that described above and used in examples 10 and 11 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then 24.21g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.68g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.64g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. Then, 0.89g of glacial acetic acid and 10.61g of 12-hydroxystearic acid were added and mixed for 10 minutes. Then, 55.06g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns was added and allowed to mix for 5 minutes. Then, 39.08g of water was added. The mixture was then heated until the temperature reached 160F. The temperature was maintained at 160F to 170F for two hours and 30 minutes. During this time, an additional 15ml of water was added, as some of the initially added water had evaporated. The temperature was then raised to 190F, immediately after which 13.19g of hexylene glycol was added. In addition, another 25ml of water was added. Once visible conversion has begun, the temperature is maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicates that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) has occurred. Then, 7.36g of the same calcium hydroxide was added and allowed to mix for 10 minutes. Then, 1.53g of glacial acetic acid was added, followed by 27.15g of 12-hydroxystearic acid. An additional 54.31g of the same paraffin base oil was added and mixed due to the weight of the grease. Then, 9.36g of boric acid was mixed in 50g of hot water, and the mixture was added to the grease. As the grease became heavier, an additional 57.39g of the same paraffinic base oil was added. Then, 17.61g of 75% phosphoric acid aqueous solution was added and mixed and reacted. An additional 52.07g of the same paraffin-based base oil was added. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.14g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.00g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.42g of arylamine antioxidant and 5.62g of polyisobutylene polymer were added. An additional 192.05g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease has a working 60stroke penetration of 287. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 20.36%. The dropping point was 639F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Example 13: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous example 12. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to 140F (first temperature adjusted delay period) and held at 140F to 150F for two hours 30 minutes (first hold delay period), then heated to as high as 190F (second temperature adjusted delay period) for immediate addition of hexylene glycol for conversion (without second hold delay period), followed by the addition of other components as outlined in example 12. The final grease had a working 60stroke penetration of 283. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 20.88%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Example 14: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous examples 12-13. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to 110F (first temperature adjusted delay period) and held at 110F to 120F for two hours 30 minutes (first hold delay period), then heated to as high as 190F (second temperature adjusted delay period) for immediate addition of hexylene glycol for conversion (without second hold delay period), followed by the addition of other components as outlined in example 12. The final grease has a working 60stroke penetration of 287. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 21.63%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Example 15: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous examples 12-14. The only significant difference was the delayed addition of the hexanediol until the grease had been stirred and held at ambient laboratory temperature (about 25C) for a period of two hours 30 minutes (first hold delay period, without any temperature adjustment delay period), then heated to as high as 190F (second temperature adjustment delay period) for immediate addition of hexanediol for conversion (without second hold delay period), followed by the addition of other components as outlined in example 12. The final grease had a working 60stroke penetration of 279. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 21.40%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8. Note that even though the first delay (hold delay period) did not involve heating at all, in all of the greases of examples 9-14 in which the delayed hexanediol technology was used, the greases showed significant thickener yield improvements over the general range of thickener yields. Furthermore, by comparing these examples, the first temperature range did not significantly affect the percentage of overbased calcium sulfonate in these greases, although the first temperature range in the middle range of about 140-.

Example 16: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous examples 8-15. The only significant difference was the delayed addition of hexylene glycol until the grease had been mixed for 2 hours and 30 minutes at ambient laboratory temperature (first hold delay period without any temperature adjustment), then heated to 160F (second temperature adjustment delay period), and mixed for 2 hours and 30 minutes at 160F to 170F (second hold delay period), then heated up to 190F (third temperature adjustment delay period), and immediately added hexylene glycol (without third hold delay period).

The grease of example 16 was prepared as follows: 264.28g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 382.25g of solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 11.10g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a poor quality calcium sulfonate similar to that described above and used in examples 10 and 11 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. Then 24.08g of mainly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 50.59g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.84g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. Then, 0.89g of glacial acetic acid and 10.56g of 12-hydroxystearic acid were added and mixed for 10 minutes. Then, 55.56g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns was added and allowed to mix for 5 minutes. Then 38.59g of water were added. The mixture was mixed for 2 hours and 30 minutes at ambient laboratory temperature (about 25C). The mixture was then heated to 160F and held between 160F and 170F for 2 hours and 30 minutes. During this time, an additional 20ml of water was added as some of the initially added water had evaporated. The temperature was then raised to 190F, immediately after which 13.68g of hexylene glycol was added. Once visible conversion has begun, the temperature is maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicates that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) has occurred. As the grease became heavier, an additional 57.09g of the same paraffinic mineral oil was added. In addition, another 15ml of water was added. Then, 7.17g of the same calcium hydroxide was added and allowed to mix for 10 minutes. Then, 1.56g of glacial acetic acid was added, followed by 27.16g of 12-hydroxystearic acid. Then, 9.37g of boric acid was mixed in 50g of hot water, and the mixture was added to the grease. As the grease became heavier, an additional 70.35g of the same paraffin-based base oil was added. Then, 18.20% aqueous solution of phosphoric acid was added and mixed and reacted. An additional 33.49g of the same paraffin-based base oil was added. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.59g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.19g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.27g of arylamine antioxidant and 5.77g of polyisobutylene polymer were added. An additional 167.19g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 274. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 20.77%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Example 17: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous example 12. The only significant difference was that 25% of the total amount of hexylene glycol was added initially with water prior to (without delay) any heating. After the mixture was first heated to 160F (first temperature adjustment delay period) and held between 160F and 170F for 2 hours and 30 minutes (first hold delay period), the remaining hexylene glycol was added. The mixture was then immediately heated to 190F-200F for conventional conversion.

The grease of example 17 was prepared as follows: 264.39g of 400TBN overbased oil-soluble calcium sulfonate was charged to an open mixing vessel followed by 383.09g of solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F, and 10.56g of PAO having a viscosity of 4cSt at 100C. The overbased oil-soluble calcium sulfonate of 400TBN is a poor quality calcium sulfonate similar to that described above and used in examples 9 and 10 of the' 768 application. Mixing was started without heating using a planetary stirring paddle. 24.02g of predominantly C12 alkylbenzene sulfonic acid were then added. After 20 minutes of mixing, 51.55g of calcium hydroxyapatite having an average particle size of about 1 to 5 microns and 3.64g of food grade purity added calcium hydroxide having an average particle size of about 1 to 5 microns were added and allowed to mix for 30 minutes. Then, 0.90g of glacial acetic acid and 10.61g of 12-hydroxystearic acid were added and mixed for 10 minutes. 55.26g of finely divided added calcium carbonate having an average particle size of about 1 to 5 microns were then added and allowed to mix for 5 minutes. Then, 38.46g of water and 3.62g of hexylene glycol were added (about 25% of the total amount of hexylene glycol added). The mixture was then heated until the temperature reached 160F. The temperature was maintained at 160F to 170F for two hours and 30 minutes. During this time, an additional 15ml of water was added, as some of the initially added water had evaporated. 10.46g of hexanediol and 10ml of water were then added and the temperature was raised to 190F. Once visible conversion has begun, the temperature is maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicates that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) has occurred. Then, 7.55g of the same added calcium hydroxide was added and allowed to mix for 10 minutes. Then, 1.54g of glacial acetic acid and 27.13g of 12-hydroxystearic acid were added to the grease. Due to the weight of the grease, an additional 57.31g of the same paraffin base oil was added and mixed. Then, 9.36g of boric acid was mixed in 50g of hot water, and the mixture was added to the grease. Then, 17.78g of 75% phosphoric acid aqueous solution was added and mixed and reacted. An additional 54.03g of the same paraffin-based base oil was added. The mixture was then heated with an electric heating mantle while continuing to stir. When the grease reached 300F, 22.48g of styrene-ethylene-propylene copolymer was added as a crumb-forming solid. The grease was further heated to about 390F at which time all of the polymer melted and was completely dissolved in the grease mixture. The heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 300F, 33.16g of food grade anhydrous calcium sulfate having an average particle size of about 1 to 5 microns was added. When the temperature of the grease was cooled to 200F, 2.41g of arylamine antioxidant and 4.41g of polyisobutylene polymer were added. An additional 232.52g of the same paraffin-based base oil was added. Mixing was continued until the grease reached a temperature of 170F. The grease was then removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 296. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 20.59%. Drop point > 650F. It can be seen that the grease has an improved thickener yield compared to the grease of example 8.

Table 2 below summarizes the results and methods used in examples 8-17 herein. All of these examples use calcium hydroxyapatite, added calcium carbonate and added calcium hydroxide as calcium containing base for reaction with complex acid and all use poor quality overbased calcium sulfonates. These examples together strongly show that thickener yield is improved by delaying the addition of the non-aqueous converting agent even when poor quality overbased calcium sulfonates are used, and even when no heating is applied prior to the first hold delay period (ambient temperature hold delay period). Complex greases also exhibit excellent drop points.

TABLE 2 Complex overbased calcium sulfonate greases

The following two examples further demonstrate the superior performance of the overbased calcium sulfonate greases of the present invention, which may be achieved by delayed addition of a non-aqueous converting agent and have different delay periods and temperature ranges for the duration of each delay period.

Example 18: another complex calcium sulfonate grease was prepared similar to the embodiment of U.S. patent 4,560,489 (issued to Witco, 24.12.1985) without the delayed addition of a non-aqueous converting agent as a baseline comparative example). The grease of example 18 was prepared as follows: 440.02g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 390.68g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 12 of the' 768 application. Then 17.76g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 44.41g of water were added followed by 14.37g of hexylene glycol. The batch was then heated with continued mixing until the temperature reached 190F. When the temperature reached 190F, 5.75g of glacial acetic acid were added. Once visible conversion of the grease structure was observed, the temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. Then, 15.37g of added calcium hydroxide of food grade purity having an average particle size of about 1 to 5 microns was added and allowed to mix for 10 minutes. Then, 28.59g of 12-hydroxystearic acid was added and melted and reacted. Then, 25.33g of boric acid was mixed with 50ml of hot water, and the mixture was added to the grease. The grease was then heated to 330F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The working 60stroke penetration of the grease was 291 and the dropping point was > 650F. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 46.92%.

Example 19: another calcium sulfonate complex grease was prepared in a similar manner to the grease of previous example 18. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to 160F (first thermoregulation delay period) and held at 160F to 170F for two hours 30 minutes (first hold delay period), then heated to as high as 190F (second thermoregulation delay period), and immediately added hexylene glycol (without second hold delay period). The grease of example 19 was prepared as follows: 440.46g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 387.69g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 12 of the' 768 application. Then 17.64g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 44.0g of water was added. The mixture was then heated to 160F and held between 160F and 170F for 2 hours and 30 minutes. During this time, an additional 43ml of water was added, since most of the initially added water had evaporated. The batch was then heated to 190F and 14.49g of hexylene glycol and 5.73g of glacial acetic acid were added immediately. Once visible conversion of the grease structure was observed, the temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. During this time, another 20ml of water was added, as some of the earlier added water had evaporated. An additional 3.73g of the same paraffin-based base oil was added followed by 15.37g of food grade pure calcium hydroxide having an average particle size of about 1 to 5 microns. It was allowed to mix for 10 minutes. Then, 28.59g of 12-hydroxystearic acid was added and melted and reacted. Then, 25.31g of boric acid was mixed with 50ml of hot water, and the mixture was added to the grease. The grease was then heated to 330F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 260. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 46.90%. Drop point > 650F. It is noted that this grease had substantially the same percentage of overbased calcium sulfonate as the grease of example 18 above. However, the working penetration of this grease was 31 points harder. Thus, the delayed glycol process used in the grease results in an increase in thickener yield. Indeed, using a linear dilution relationship of the working penetration to the percentage of overbased calcium sulfonate in the final grease, the predicted percentage of overbased calcium sulfonate in the grease of example 19 would be 41.9% if diluted with sufficient base oil to obtain the same working penetration of the grease of example 18. In addition, very high dropping points were maintained in the grease of example 19. These examples further show that when using poor quality overbased calcium sulfonates (as in examples 9-17), delayed addition of the non-aqueous conversion agent improves thickener yield and achieves higher results than when using high quality overbased calcium sulfonates (as in examples 18-19). The results of these examples are summarized in table 3 below.

TABLE 3

Example numbering	18	19
			% overbased calcium sulfonates	46.92	46.9(41.9)
Quality of calcium sulfonate	Good effect	Good effect
			Added calcium base	Calcium hydroxide	Calcium hydroxide
Work penetration 60	291	260
			Dropping Point, F	>650	>650
Delay of addition of non-aqueous converting agent	Whether or not	Is that
			First temperature range, F	N/A	160-170
First hold delay period, hours	N/A	2.5
			Second delay of temperature regulation period	N/A	Is that
A second temperature range, F	N/A	190
			Second hold delay period, hours	N/A	Without immediate addition

Further examples showing the results of delayed addition of non-aqueous converting agent in simple calcium sulfonate greases are known in examples 20-23. These examples also show that when the addition is delayed relative to the pre-conversion addition of water, improved thickener yields can be obtained using either hexylene glycol or propylene glycol as the non-aqueous conversion agent. Similar results are expected for other non-aqueous converting agents where the addition is delayed relative to the addition of water.

Example 20: simple calcium sulfonate greases were prepared similar to the embodiments in the ranges of us patents 3,377,283 and 3,492,231 (issued to Lubrizol corporation on 4-9-d.1968 and 1-27-d.1970, respectively) without any delay for use as baseline comparative examples. The grease of example 20 was prepared as follows: 496.49g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 394.45g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 12 of the' 768 application. Then, 20.23g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 44.23g of water were added followed by 16.57g of hexylene glycol. The batch was then heated with continued mixing until the temperature reached 190F. When the temperature reached 190F, 6.20g of glacial acetic acid were added. Once visible conversion of the grease structure was observed, the temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. During this time, another 10ml of water was added. The resulting grease was then heated to 330F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the temperature reached 200F, 2.34g of arylamine antioxidant was added. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 331. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 53.03% and the drop point was > 650F.

Example 21: another simple calcium sulfonate grease was prepared in a similar manner to the grease of previous example 20. The only significant difference was the delayed addition of hexylene glycol until the grease had been heated to 160F (first thermoregulation delay period) and held at 160F to 170F for two hours 30 minutes (first hold delay period), then heated to as high as 190F (second thermoregulation delay period), and immediately added hexylene glycol (without second hold delay period). Grease was prepared as follows: 495.41g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 391.96g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 12 of the' 768 application. Then, 19.65g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 44.42g of water were added. The mixture was then heated to 160F and held between 160F and 170F for 2 hours and 30 minutes. During this time, an additional 50ml of water was added, as most of the initially added water had evaporated. The batch was then heated to 190F and 16.53g of hexylene glycol followed by 6.34g of glacial acetic acid were added. Once visible conversion of the grease structure was observed, the temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. During this time, an additional 10ml of water was added. The resulting grease was then heated to 330F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the temperature reached 200F, 2.32g of arylamine antioxidant was added. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. Example 21 dropping point of grease > 650F. The working 60stroke penetration of the grease was 290. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 53.14%.

It is noted that the grease of example 21 and the grease of the previous example 20 have substantially the same percentage of overbased calcium sulfonate. However, the working penetration of this grease was 41 points harder. Thus, the delayed glycol process used in the grease results in an increase in thickener yield. Indeed, using a linear dilution relationship of the working penetration to the percentage of overbased calcium sulfonate in the final grease, the predicted percentage of overbased calcium sulfonate in the example 21 grease would be 46.6% if diluted with sufficient base oil to obtain the same working penetration for the example 20 grease. Furthermore, the dropping point is kept very high.

Example 22: another simple calcium sulfonate grease was prepared in a similar manner to the grease of previous example 20. However, propylene glycol is used as the non-aqueous converting agent instead of hexylene glycol. This was done to demonstrate that the increase in thickener yield observed in the previous examples was not specific to one non-aqueous conversion agent only. Embodiment 22 is a baseline embodiment in which no delay is used. Grease was prepared as follows: 550.60g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 354.69g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 11 of the' 768 application. Then, 22.23g of predominantly C12 alkylbenzene sulfonic acid were added. After mixing for 20 minutes, 49.59g of water were added followed by 12.35g of propylene glycol. The batch was then heated with continued mixing until the temperature reached 190F. 6.87g of a portion of glacial acetic acid are added. Once visible conversion of the grease structure was observed, the temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. During this time, an additional 20ml of water was added. The resulting grease was then heated to 330F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the temperature reached 200F, 2.41g of arylamine antioxidant was added. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 258. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 58.01%. The dropping point was 600F.

Example 23: another simple calcium sulfonate grease was prepared in a similar manner to the previous grease of example 22. The only significant difference was the delayed addition of propylene glycol until the grease had been heated to 160F (first thermoregulation delay period) and held at 160F to 170F for two hours 30 minutes (first hold delay period) and then heated up to 190F (second thermoregulation delay period). Grease was prepared as follows: 550.71g of 400TBN overbased oil-soluble calcium sulfonate was added to an open mixing vessel followed by 354.74g of a solvent neutral group 1 paraffinic base oil having a viscosity of about 600SUS at 100F. Mixing was started without heating using a planetary stirring paddle. The overbased oil-soluble calcium sulfonate of 400TBN is a high quality calcium sulfonate similar to that described above and used in examples 4 and 11 of the' 768 application. 22.92g of predominantly C12 alkylbenzene sulfonic acid were then added. After mixing for 20 minutes, 49.23g of water were added. The mixture was then heated to 160F and held between 160F and 170F for 2 hours and 30 minutes. During this time, an additional 35ml of water was added, as most of the initially added water had evaporated. The batch was then heated with continued mixing until the temperature reached 190F. When the batch reached 190F, 12.27g of propylene glycol and 6.89g of glacial acetic acid were added immediately (without a second hold delay period). Once visible conversion of the grease structure was observed, the temperature was maintained between 190F and 200F for 45 minutes until Fourier Transform Infrared (FTIR) spectroscopy indicated that conversion of amorphous calcium carbonate to crystalline calcium carbonate (calcite) had occurred. During this time, an additional 15ml of water was added. The resulting grease was then heated to 330F. Then, the heating mantle was removed and the grease was allowed to cool by continued stirring outside the room. When the temperature reached 200F, 2.38g of arylamine antioxidant was added. When the grease was cooled to 170F, the grease was removed from the mixer and passed through a three-roll mill three times to obtain the final smooth uniform texture. The grease had a working 60stroke penetration of 239. The percentage of overbased oil-soluble calcium sulfonate in the final grease was 57.97%. The dropping point was 591F.

Again by comparing this grease with the previous grease of example 22, it is possible to see the increase in thickener yield resulting from the delayed addition of the non-aqueous conversion agent. The percentage of overbased calcium sulfonate in this example 23 grease was actually slightly lower than the percentage of the grease of the previous example 22. Even so, the working penetration of the grease of this example 23 was harder to about 20 points. Indeed, using a linear dilution relationship of working penetration to the percentage of overbased calcium sulfonate in the final grease, the predicted percentage of overbased calcium sulfonate in the grease of example 23 would be 53.6% if diluted with sufficient base oil to obtain the same working penetration of the grease of example 22. The grease of examples 22 and 23 had a lower drop point than the other prior greases, indicating that propylene glycol is not as effective as hexylene glycol as a converting agent, at least under the conditions in which each was used. Nevertheless, delayed addition of propylene glycol improves thickener yield compared to greases in which its addition is not delayed. The results of these examples are summarized in table 4 below.

TABLE 4 simple overbased calcium sulfonate greases

Example numbering	20	21	22	23
					% overbased calcium sulfonates	53.03	53.14(46.6)	58.01	57.97(53.6)
Work penetration 60	331	290	258	239
					Dropping Point, F	>650	>650	600	591
Nonaqueous conversion agent	Hexanediol	Hexanediol	Propylene glycol	Propylene glycol
					Delay of addition of non-aqueous converting agent	Whether or not	Is that	Whether or not	Is that
First temperature range, F	N/A	160-170	N/A	160-170
					First duration of maintenance, hours	N/A	2.5	N/A	2.5
Second retardation temperature range, F	N/A	190	N/A	190
					Second hold duration, hours	N/A	Without immediate addition	N/A	Without immediate addition

These examples show that the delayed addition of the non-aqueous conversion agent consistently improves thickener yield despite the previously described use of calcium sulfonate based grease technology. Furthermore, as defined in the' 768 application, an increase in thickener yield can be observed regardless of whether overbased calcium sulfonate is used that is of good quality or poor quality, although greater increases (contrary to expectations) are achieved using poor quality calcium sulfonate within the exemplary compositional ranges included herein.

The exemplary greases prepared according to the delayed addition method of the present invention described above also exhibited different physical properties than the exemplary greases in which the addition of all or some of the non-aqueous conversion agent was not delayed, even though the various components and amounts thereof used in the various comparative groups of the examples were the same or substantially similar. Testing of samples of exemplary greases using fourier transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) showed that greases made with delayed addition according to the invention could be distinguished from similar compositions made without delay. For example, there are differences in adsorption profile distribution and differences in particle size and configuration.

While the examples provided herein fall primarily within NLGI grade No. 1, No. 2, or No. 3, with grade No. 2 being most preferred, it is further understood that the scope of the present invention includes all NLGI consistency grades that are harder and softer than grade No. 2. However, for such greases according to the invention that are not NLGI No. 2 grades, their performance should be consistent with that obtained if more or less base oil had been used to provide a No. 2 grade product, as will be understood by those of ordinary skill in the art.

As used herein, the term "thickenerYield "when applied to the present invention shall be in the conventional sense, i.e. the concentration of highly overbased oil-soluble calcium sulfonate required to provide a grease of a particular desired consistency, as measured by the standard penetration test ASTM D217 or D1403 commonly used in grease manufacture. In a similar manner, as used herein, the "drop point" of a grease shall refer to the value obtained by using the standard drop point test ASTM D2265, which is commonly used in grease manufacture. As used herein, reference to adding an ingredient immediately after the temperature is reached means that the ingredient is added immediately after the temperature is reached, as it is physically possible to give the amount to be added and the equipment used, but if preferred within a short time, less than 10 minutes, more preferably less than 5 minutes, after the mixture reaches about the indicated temperature. As used herein: (1) the amount of dispersed calcium carbonate or residual calcium oxide or calcium hydroxide contained in the overbased calcium sulfonate is based on the 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 of the ingredient; and (3) all other amounts (including total amounts) of ingredients expressed in percentages or parts are by weight of the final grease product, even though a particular ingredient (such as water) may not be present in the final grease or may not be present in the final grease in a determined amount added as an ingredient. As used herein to describe the invention (as opposed to how the term is used in certain prior art references), calcium hydroxyapatite refers to (1) calcium hydroxyapatite having the formula Ca₅(PO₄)₃The compound of OH or (2) the mathematically equivalent formula (a) has a melting point of about 1100C or (b) mixtures of tricalcium phosphate and calcium hydroxide are specifically excluded by such equivalent formulas. One of ordinary skill in the art, upon reading this specification (including the examples contained herein), will understand that modifications and variations can be made to the compositions and methods of making the compositions within the scope of the present invention, and it is intended that the scope of the invention disclosed herein be limited only by the broadest interpretation of the appended claims to which the inventors are legally entitled.

Claims

1. A method for preparing a calcium sulfonate grease comprising the steps of:

adding and mixing water, overbased calcium sulfonate containing dispersed amorphous calcium carbonate, and optionally a base oil to form a first mixture;

adding and mixing one or more non-aqueous conversion agents to the first mixture to form a pre-conversion mixture, wherein at least a first portion of the one or more non-aqueous conversion agents comprises hexylene glycol or propylene glycol added after one or more delay periods;

converting the pre-conversion mixture to a converted mixture by heating to a temperature between 190 ° F and 230 ° F until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to crystalline calcium carbonate occurs; and is

Wherein the grease is a complex calcium sulfonate grease containing 30 wt% or less of overbased calcium sulfonate, or the grease is a simple calcium sulfonate grease containing 30 to 70 wt% of overbased calcium sulfonate, and

wherein the one or more delay periods comprise (a) a hold delay period, wherein the first mixture or the pre-conversion mixture is held at a temperature or a temperature range for a period of at least 20 minutes prior to addition of the first portion; or

(b) A temperature conditioning delay period wherein the first mixture or the pre-conversion mixture is heated to a temperature of at least 190 ° F; or (c) a temperature regulation delay period, wherein the first mixture or the pre-conversion mixture is heated to a first temperature or a first temperature range, and a holding delay period, wherein the first mixture or the pre-conversion mixture is held at the first temperature or within the first temperature range prior to addition of a portion of hexylene glycol or propylene glycol, wherein the first temperature or first temperature range is between 110 ° F and 170 ° F, and the holding delay period is at least 150 minutes.

2. The method of claim 1, further comprising adding at least a second portion of one or more of the non-aqueous conversion agents to one or more of: (1) the first mixture prior to any delay period; (2) the first mixture after or during a delay period; or (3) the pre-conversion mixture after or during one or more lag phases; and is

Wherein the second portion may be the same non-aqueous converting agent as the first portion, or a different non-aqueous converting agent.

3. The process of claim 2, wherein acetic acid is not added prior to the converting step.

4. The method of claim 1, wherein the grease is a complex grease, and further comprising the steps of:

mixing one or more complex acids with the first mixture, the pre-conversion mixture, the converted mixture, or a combination thereof;

mixing at least one calcium-containing base with the first mixture, the pre-conversion mixture, the converted mixture, or a combination thereof, wherein the calcium-containing base comprises calcium hydroxyapatite, added calcium carbonate, or a mixture thereof; and is

Wherein the overbased calcium sulfonate comprises 0 to 8 weight percent residual calcium oxide or calcium hydroxide.

5. The method of claim 2, wherein the second portion of the one or more non-aqueous conversion agents is a glycol, glycol ether, or glycol polyether.

6. The method of claim 5, wherein the first or second portion of diol is hexylene glycol.

7. The method of claim 6, wherein the first portion is hexylene glycol and the second portion is hexylene glycol added to the first mixture or the pre-conversion mixture after or during one or more delay periods; and is

Wherein the one or more delay periods between the addition of the first and second portions of hexylene glycol is (1) a hold delay period of at least 20 minutes; or (2) a temperature conditioning delay period during which the first mixture or the pre-conversion mixture is heated to a temperature of at least 160 ° F; or (3) both.

8. The method of claim 1, wherein the mixing and the converting are performed in an open vessel.

9. The method of claim 1, wherein the converting is performed in a pressurized vessel.

10. The method of claim 2, wherein said second portion of one of said non-aqueous conversion agents is added to said first mixture or said pre-conversion mixture during a delay period by continuous addition at a substantially steady flow rate for the duration of said delay period or by discrete addition in substantially uniform increments.

11. The method of claim 10, wherein said second portion of non-aqueous conversion agent is added in portions to said first mixture or said pre-conversion mixture after a delay period, and wherein the continuously added portion is the same or different non-aqueous conversion agent as the portion added in portions.

12. A method for preparing a calcium sulfonate grease comprising the steps of:

mixing water, overbased calcium sulfonate containing dispersed amorphous calcium carbonate, and optionally a base oil to form a first mixture;

adding one or more non-aqueous conversion agents to the first mixture to form a pre-conversion mixture, wherein at least a first portion of the one or more non-aqueous conversion agents comprises hexylene glycol or propylene glycol added after one or more delay periods;

converting the pre-conversion mixture to a converted mixture by heating to a temperature between 190 ° F and 230 ° F until conversion of the amorphous calcium carbonate contained in the overbased calcium sulfonate to crystalline calcium carbonate occurs;

wherein the grease is a complex calcium sulfonate grease comprising 45 wt% or less of overbased calcium sulfonate, or the grease is a simple calcium sulfonate grease comprising 30 to 70 wt% of overbased calcium sulfonate; and is

Wherein the one or more delay periods comprise a hold delay period, wherein the first mixture or the pre-conversion mixture is held at a temperature or temperature range for a period of at least 20 minutes prior to addition of the first portion.

13. The method of claim 12 wherein the overbased calcium sulfonate is a poor quality overbased calcium sulfonate.

14. The method of claim 12, wherein the overbased calcium sulfonate is a high quality overbased calcium sulfonate.

15. The method of claim 12, wherein the grease is a complex grease, and further comprising the steps of:

16. The method of claim 15, wherein no additional calcium oxide or calcium hydroxide is added as the calcium-containing base for reaction with the complex acid.

17. The method of claim 15, wherein the calcium-containing base comprises calcium hydroxyapatite and one or more of: added calcium oxide, added calcium hydroxide and added calcium carbonate.

18. The method of claim 12, wherein the temperature or temperature range is between ambient temperature and 190 ° F.

19. The method of claim 12, wherein the time period for the hold delay period is at least 30 minutes.

20. The method of claim 12, wherein there are at least two delay periods.

21. The method of claim 20, wherein one of the delay periods is a temperature adjusted delay period in which the first mixture or the pre-conversion mixture is heated or cooled.

22. The method of claim 20, wherein at least one other portion of one of said non-aqueous conversion agents is added during or after a second or any subsequent delay period, wherein any said other portion may be the same non-aqueous conversion agent as said first portion or any other portion, or a different non-aqueous conversion agent.

23. The method of claim 20, wherein no non-aqueous conversion agent is added during or immediately after the first delay period.

24. The method of claim 20, wherein said first portion of one of said non-aqueous conversion agents is added in portions after one delay period, and a second portion of the same or different non-aqueous conversion agent is added continuously during a further delay period.

25. The method of claim 20, wherein a second portion of one of said non-aqueous conversion agents is added after or during a delay period, and said second portion is the same as or different from said first portion.

26. The method of claim 20, wherein the second portion of one of the non-aqueous conversion agents is added to one or more of: (1) the first mixture prior to any delay period; (2) the first mixture after or during one or two delay periods; or (3) the pre-conversion mixture after or during one or two delay periods; and wherein the second part is the same non-aqueous converting agent as the first part.

27. The method of claim 22, wherein the second portion of the non-aqueous conversion agent is a glycol, glycol ether, or glycol polyether.

28. The method of claim 27, wherein the diol is hexylene glycol.

29. The process of claim 28, wherein the first portion is hexylene glycol and the second portion is added (1) with the first mixture prior to any delay period or (2) to the pre-conversion mixture after or during one or more delay periods; and is

Wherein the one or more delay periods between the addition of the first portion and the second portion of hexylene glycol is (1) a hold delay period of at least 20 minutes; or (2) a temperature conditioning delay period during which the first mixture or the pre-conversion mixture is heated to a temperature of at least 160 ° F; or (3) both.

30. The method of claim 14, wherein there are at least three delay periods.

31. The method of claim 30, wherein a first delay period is a temperature conditioning delay period in which the first mixture is heated or cooled to a first temperature or first temperature range, a second delay period is the holding delay period in which the first mixture or the pre-conversion mixture is held at the first temperature or first temperature range for a period of time, and a third delay period is a temperature conditioning period in which the first mixture or the pre-conversion mixture is heated or cooled to a second temperature or second temperature range.

32. The method of claim 30, wherein a first delay period is the holding delay period in which the first mixture is held at ambient temperature for a period of time; the second delay period is a thermoregulation delay period in which the first mixture or the pre-conversion mixture is heated or cooled to a first temperature or a first temperature range, and the third delay period is another holding delay period in which the first mixture or the pre-conversion mixture is held at the first temperature or first temperature range for a period of time.

33. The method of claim 12, wherein the mixing and the converting are performed in an open vessel.

34. The method of claim 12, wherein the converting is performed in a pressurized vessel.

35. The method of claim 12, wherein at least one of the delay periods is one hour or more.

36. The method of claim 12, wherein each delay period is at least 20 minutes.

37. The method of claim 12, wherein each delay period is at least 30 minutes.

38. The method of claim 12, wherein a second portion of one of the non-aqueous converting agents is added to the first mixture or the pre-conversion mixture, and wherein the second portion is methanol, isopropanol, or another low molecular weight alcohol.

39. The method of claim 12, wherein a second portion of one of the non-aqueous converting agents is added to the first mixture or the pre-conversion mixture, and wherein the second portion is not methanol, isopropanol, or another low molecular weight alcohol.

40. The method of claim 1, wherein the grease is a complex calcium sulfonate grease comprising 22 wt% or less of overbased calcium sulfonate.

41. The method according to claim 40, further comprising adding at least one second portion of one or more of said non-aqueous conversion agents to one or more of: (1) the first mixture prior to any delay period; (2) the first mixture after or during a delay period; or (3) the pre-conversion mixture after or during one or more lag phases; and is

42. The method of claim 40, wherein the grease is a complex grease, and further comprising the steps of:

43. The method of claim 40, wherein said mixing and said converting are performed in an open vessel.

44. The method of claim 40, wherein the converting is performed in a pressurized vessel.

45. The method of claim 1 or 40, wherein at least one of the delay periods is one hour or more.

46. The method of claim 1 or 40, wherein each delay period is at least 20 minutes.

47. The method of claim 1 or 40, wherein the overbased calcium sulfonate is a high quality overbased calcium sulfonate.

48. The method of claim 1 or 40, wherein there is at least one delay period before adding any non-aqueous conversion agent.

49. The method of claim 1 or 40, wherein the overbased calcium sulfonate is a poor quality overbased calcium sulfonate.

50. The method of claim 1 or 40, wherein there is a temperature regulation delay period during which the first mixture is heated to a first temperature or first temperature range, and a holding delay period during which the first mixture is held at the first temperature or within the first temperature range prior to adding the first portion of the one or more non-aqueous conversion agents.

51. The method of claim 50, wherein the first temperature or first temperature range is between 140 ° F and 170 ° F.

52. The method of claim 51, wherein the non-aqueous conversion agent is not added prior to the first delay period.

53. The method of claim 51, wherein the grease is a complex grease comprising 30 wt% or less of high quality overbased calcium sulfonate or a complex grease comprising 22 wt% or less of low quality overbased calcium sulfonate.

54. The method of claim 1, wherein the grease is a simple grease.

55. The method of claim 12, wherein the grease is a simple grease.

56. The process of claim 2, wherein any acetic acid added prior to the converting step is completely added prior to any lag period.

57. The method of claim 1 or 40, wherein any holding delay period is a period of time that holds the first mixture or the pre-conversion mixture at a temperature or a range of temperatures for at least 30 minutes.