EP2134822A2 - Capped polyester polyol lubricant composition - Google Patents

Abstract

The present invention relates to polyester polyol lubricant compositions, some of which are capped, that include two or more chemically linked ester moieties, at least one of which derives from a seed or vegetable oil, and their preparation. The compositions have a pour point temperature of -10° centigrade or less without a pour point depressant and a viscosity at 25° centigrade within a range of 40 centipoises (0.04 pascal second) to 2000 centipoises (2 pascal seconds) when they either lack an initiator moiety or include an initiator moiety other than a dendritic initiator moiety, and a pour point temperature of -5° centigrade or less without a pour point depressant and a viscosity at 25° centigrade within a range of 40 centipoises (0.04 pascal second) to 8000 centipoises (8 pascal seconds) when they include a dendritic initiator moiety. The present invention also relates to a process for removing at least a portion of saturates from said compositions.

Description

CAPPED POLYESTER POLYOL LUBRICANT COMPOSITION

This application claims benefit of U.S. Provisional Application Serial No. 60/922,476, filed on April 9, 2007. The present invention relates generally to a capped polyester polyol lubricant composition. The present invention relates more particularly to capped polyester polyol lubricant compositions based upon a renewable raw material source such as a seed or vegetable oil, whether genetically modified or not. The present invention relates still more particularly to capped polyester polyol compositions wherein the renewable raw material source is an alkanolyzed, hydroformylated and reduced seed or vegetable oil.

"Bio-lubricants", or lubricants based upon renewable resources such as seed oils and vegetable oils rather than from petroleum or natural gas, represent a small, but growing segment of total global lubricants demand. Bio-lubricants find particular favor in environmentally sensitive applications such as marine, forestry or agricultural lubricants due to observations that they readily biodegrade, have low toxicity and do not appear to harm aquatic organisms and surrounding vegetation. In at least partial recognition of such observations, Germany and Austria ban use of mineral oils in total loss lubrication applications such as chain saw lubrication and Portugal and Belgium mandate use of biodegradable lubricants in outboard engines. Technical performance shortcomings of unmodified seed oils, relative to synthetic lubricants derived from petroleum or natural gas such as polyol esters, polyalkylene glycols and poly(alpha-olefins), in terms of hydrolytic stability, oxidative stability and low temperature properties including pour point limit growth of such seed oils as bio-lubricants. For example, in cold climates (temperatures below -10° centigrade (⁰C)), vegetable oils tend to solidify more readily than petroleum- based products and, accordingly, have relatively high (from 0 ⁰C to -20 ⁰C) pour point temperatures. Addition of a pour point depressant to vegetable oils yields a composition with lower pour point temperature than that of neat (no additives) vegetable oil.

United States Patent (USP) 5,335,471 discloses use of methacrylate and styrene/maleic anhydride interpolymers as pour point depressant additives for seed oil lubricants.

USP 5,413,725 teaches use of the same interpolymers as pour point depressant additives for seed oil lubricants derived from high oleic containing feedstocks. USP 4,243,818 defines "hydroformylation" at column 5, lines 8-12 as the production of aldehydes from unsaturated compounds by reaction with hydrogen and carbon monoxide in the presence of a catalyst. The preferred unsaturated compound, per column 5, lines 36- 38, is oleyl alcohol, but linoleyl alcohol or linolenyl alcohol may also be used as the unsaturated compound. At column 9, lines 52-58, '818 teaches use of an acid halide such as acryloyl chloride to convert the alcohols to their corresponding unsaturated esters (e.g. an acrylate or a methacrylate).

As used throughout this specification, definitions presented in this paragraph, in succeeding paragraphs or elsewhere in the specification, have meanings ascribed to them where first defined.

When ranges are stated herein, as in a range of from 2 to 10, both end points of the range (e.g. 2 and 10) are included within the range unless otherwise specifically excluded.

A first aspect of the present invention is a capped polyester polyol lubricant composition, the composition comprising at least two ester moieties, the ester moieties optionally being chemically linked one to another either (a) directly, or (b) indirectly by way of an initiator moiety, said composition also having a hydroxyl percentage within a range of from 0.1 percent by weight to 2 percent by weight, each percent by weight being based upon composition weight, and a 12 carbon atom and higher carbon number saturated hydrocarbon content within a range of from 0 percent by weight to 32 percent by weight, each percent by weight being based upon composition weight, a viscosity at 25° centigrade within a range of from 40 centipoises (cps) (0.04 pascal second (Pa.s)) to 2000 cps (2 Pa.s), and a pour point of -10° centigrade or less.

A second aspect of the present invention is a polyester polyol lubricant composition, the composition comprising a plurality of ester moieties, the ester moieties being chemically linked one to another indirectly by way of a dendritic initiator moiety, and a hydroxyl percentage within a range of from 0.1 percent by weight to 31 percent by weight, each percent by weight being based upon composition weight, and a 12 carbon atom and higher carbon number saturated hydrocarbon content within a range of from 0 percent by weight to 32 percent by weight, each percent by weight being based upon composition weight, a viscosity at 25° centigrade within a range of from 40 centipoise to 8000 centipoise, and a pour point of -5° centigrade or less. The dendritic initiator moiety is preferably derived from a dendritic base product or an alkoxylated version thereof. Polyester polyol lubricant compositions of the present invention, whether capped or not, have utility as, for example, a hydraulic fluid. Hydraulic fluids are used in a variety of apparatus common to industrial segments including mining, steel, die-casting, and food processing, as well as forestry and marine equipment. Furthermore, such lubricant compositions also have potential utility in the automotive segment as, for example, engine oils, transmission fluids and gear oils or as components of such oils or fluids, fluids in applications such as gear oils, transmission fluids, engine oils and compressor fluids. Skilled artisans who work with lubricant compositions readily understand other suitable end use applications for the lubricant compositions of the present invention. A third aspect of the present invention is a method of preparing a polyester polyol lubricant composition, especially a capped polyester polyol lubricant composition of the first aspect, which method comprises: a. subjecting a reaction mixture that comprises a monomer (preferably an alkanolized, hydroformylated and reduced seed oil), a capping agent, a catalyst and, optionally, an initiator to an elevated temperature within a range of from 170° centigrade to 200° centigrade to convert at least a portion of the reaction mixture to a capped polyester polyol and a volatile byproduct; and b. concurrently removing at least a portion of the volatile byproduct.

A fourth aspect of the invention is a method of preparing a polyester polyol lubricant composition, especially a polyester polyol lubricant composition of the second aspect, which method comprises: a. subjecting a reaction mixture that comprises a monomer (preferably an alkanolized, hydroformylated and reduced seed oil), a catalyst and, optionally, an initiator to an elevated temperature within a range of from 170° centigrade to 200° centigrade to convert at least a portion of the reaction mixture to a polyester polyol and a volatile byproduct; and b. concurrently removing at least a portion of the volatile byproduct.

The method of either the third aspect or the fourth aspect preferably further comprises a plurality of sequential precursor steps to prepare the alkanolized, hydroformylated and reduced seed oil (monomer), the sequential precursor steps comprising, in order: al. alkanolizing a seed oil to convert glycerides present in the seed oil to a mixture of saturated and unsaturated fatty acid esters of the alkanol, the alkanol having a straight-chain or branched structure and containing from 1 carbon atom (C₁) to 15 carbon atoms (C₁₅); a2. hydroformylating the mixture of saturated and unsaturated fatty acid esters to convert said mixture to an aldehyde or mixture of aldehydes; and a3. reducing the aldehyde or mixture of aldehydes in a hydrogen atmosphere with assistance of a hydrogenation catalyst to convert said aldehyde or mixture of aldehydes to an alcohol composition of hydroxymethyl-substituted fatty acids or hydroxymethyl- substituted fatty acid esters.

Step a2. preferably occurs in a non-aqueous reaction medium together with a solubilized Group VIII transition metal-organophosphine ligand complex catalyst, optionally with a solubilized free organophosphine metal salt ligand.

As used herein, "monomer" refers to a compound that has both an alcohol functionality and either an acid functionality or an ester functionality. Preferred monomers include alkanolyzed, hydroformylated and reduced seed oils. A fifth aspect of the invention is a method for removing at least a portion of saturates from the capped polyester polyol lubricant composition of the first aspect or the polyester polyol lubricant composition of the second aspect, which method comprises feeding a heated feedstream, the feed stream being the capped polyester polyol lubricant composition or the polyester polyol lubricant composition, to a wiped film evaporator that operates under a reduced pressure to separate the feed stream into a saturate-rich portion and a saturate-depleted remainder. The feed stream is preferably heated to a temperature within a range of from 90 degrees centigrade to 150 degrees centigrade, and the reduced pressure is preferably within a range of from 0.01 millimeters of mercury to 1 millimeters of mercury. In a preferred variation of the fifth aspect, the saturate-depleted stream from one pass through the wiped film evaporator is used as the heated feedstream for a subsequent pass through the wiped film evaporator, thereby further reducing saturate content of the saturate- depleted stream.

As used herein, "capping agent" refers to an ester or carboxylic acid that lacks an alcohol functionality. Suitable capping agents include short chain carboxylic acids or short chain lower alkyl esters of six to twelve carbon atom carboxylic acids (C_O-C₁₂), preferably short chain carboxylic acids or short chain lower alkyl esters of six to ten carbon atom (C₆- Cio) carboxylic acids, more preferably short chain carboxylic acids or short chain lower alkyl esters of Cs and C_1O carboxylic acids, mixtures of two or more of such carboxylic acids or lower alkyl esters (e.g. a mixture of short chain lower carboxylic acids or short chain lower alkyl esters of Cs and C_1O carboxylic acids), and even more preferably one or more carboxylic acids or methyl esters of such carboxylic acids. References to the Periodic Table of the Elements herein shall refer to the Periodic

Table of the Elements, published and copyrighted by CRC Press, Inc., 2003. Also, any references to a Group or Groups shall be to the Group or Groups reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups.

Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight. For purposes of United States patent practice, the contents of any patent, patent application, or publication referenced herein are hereby incorporated by reference in their entirety (or the equivalent US version thereof is so incorporated by reference) especially with respect to the disclosure of synthetic techniques, definitions (to the extent not inconsistent with any definitions provided herein) and general knowledge in the art.

The term "comprising" and derivatives thereof is not intended to exclude the presence of any additional component, step or procedure, whether or not the same is disclosed herein. In order to avoid any doubt, all compositions claimed herein through use of the term "comprising" may include any additional additive, adjuvant, or compound whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, "consisting essentially of" excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term "consisting of" excludes any component, step or procedure not specifically delineated or listed. The term "or", unless stated otherwise, refers to the listed members individually as well as in any combination.

Expressions of temperature may be in terms either of degrees Fahrenheit (⁰F) together with its equivalent in degrees centigrade (⁰C) or, more typically, simply in degrees centigrade (⁰C).

Preparation of an alkanolyzed, hydroformylated and reduced seed oil (sometimes referred to as an "ester alcohol") involves three sequential steps: alkanolysis, hydroformylation and reduction. Alkanolysis, also known as transesterification, converts glycerides present in a seed oil, to a mixture of saturated and unsaturated fatty acid esters of the alkanol. Skilled artisans understand that glycerides can be difficult to process and separate and that transesterification of such glycerides yields mixtures that are more suitable for chemical transformations and separation.

The alkanol, sometimes referred to as a "lower alkanol", may have a straight-chain or branched structure and typically contains from 1 to about 15 carbon atoms (C₁ to C₁₅) , preferably from 1 to 8 carbon atoms (C₁ to Cg) and more preferably from 1 to 4 carbon atoms (C₁ to C₄). Particularly suitable alkanols include methanol, ethanol and isopropanol, with methanol being preferred. Carbon atoms in the alkanol' s alcohol segment may be substituted with a variety of substituents provided that such substituents do not interfere with processing and downstream applications.

One may choose any known direct esterification method by condensation of an alcohol moiety on one molecule and a carboxylic acid moiety on a different molecule with consequent removal of water or known transesterification methodology, with methanolysis and ethanolysis being described in, for example, Patent Cooperation Treaty Application (WO) 2001/012581, German Patent Publication (DE) 19908978, Brazilian Patent Publication (Br) 953081 and USP 3,210,325, the teachings of which are incorporated herein to the maximum extent permitted by law. Typically, in such processes, one contacts the lower alkanol with alkali metal, preferably sodium or potassium, at a temperature within a range of from about 30° C to about 100° C to prepare a corresponding metal alkoxide. One then adds seed oil to the metal alkoxide to form a reaction mixture and heats the reaction mixture to a temperature within a range of from about 30° C to about 100° C to effect transesterification. Separation of crude transesterified composition from the reaction mixture may involve standard techniques such as phase separation, extraction, distillation or a combination of two or more standard techniques. If one chooses to use a mixture of fatty acids rather than fatty acid esters, one may hydrolyze seed oils to their constituent fatty acids using conventional techniques. Such acids may be readily esterified by conventional techniques, with esterification yielding water as a byproduct.

United States Patent Application Publication (USPAP) 2006/0193802, the teachings of which are incorporated herein by reference, especially those in paragraphs [0037] through [0042], discusses hydroformylation with emphasis upon non-aqueous hydroformylation. It also refers to US 4,731,486 and US 4,633,021, especially US 4,731,486 and incorporates the teachings thereof by reference.

In general terms, hydroformylation, as practiced in this invention, comprises contacting a mixture of fatty acid esters or fatty acids, preferably derived from a seed oil, with carbon monoxide (CO) and hydrogen (H₂) in a non-aqueous reaction medium together with a solubilized Group VIII (Periodic Table of the Elements, Inside Cover, CRC Handbook of Chemistry and Physics, 77^th Edition, 1996-1997) transition metal- organophosphine ligand complex catalyst, optionally with solubilized free organophosphine metal salt ligand, under conditions sufficient to convert the fatty acid esters or fatty acids to an aldehyde or mixture of aldehydes. "Non-aqueous reaction medium", as used herein, means a reaction medium substantially free of water. In other words, any water that may be present is present in such a small amount that one does not characterize hydroformylation as including a separate water or aqueous phase in addition to an organic phase. "Free organophosphine metal salt ligand" means that the organophosphine metal salt ligand is not complexed, i.e. bound or tied to the Group VIII transition metal.

Paragraph [0038] of USPAP 2006/0193802 equates Group VIII transition metals to a group consisting of iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt), and mixtures thereof. Preferred Group Vπi transition metals include Rh, Ru, Co and Ir, with Rh and Co being more preferred and Rh being most preferred. Suitable amounts of Group VIII transition metal range from 10 parts by weight per million parts by weight (ppm) to 1000 ppm, calculated as free metal, with amounts within a range of from about 10 ppm to about 800 ppm being preferred for Rh, calculated as free metal.

Paragraph [0039] of USPAP 2006/0193802 includes teachings related to the organophosphine metal salt ligand and notes that it comprises a mono sulfonated tertiary phosphine metal salt. Paragraph [0039] refers to US 4,731,486 for non-limiting examples of such ligands. Examples of preferred ligands include mono sulfonated metal salt derivatives of triphenylphosphine, diphenylcyclohexylphosphine, phenyldicyclohexylphosphine, tricyclohexylphosphine, diphenylisopropylphosphine, phenyldiisopropylphosphine, diphenyl-t-butylphosphine, and phenyl-di-t-butylphosphine, with derivatives of phenyldicyclohexylphosphine being especially preferred. Paragraph [0040] of USPAP 2006/0193802 discloses suitable organic solubilizing agents and incorporates the teachings of US 5,180,854 and US 4,731,486 by reference. US 5,180,854 refers to organic solubilizing agents including amides, glycols, sulfoxides, sulfones and mixtures thereof. US 4,731,486 refers to alkylene oxide oligomers having an average molecular weight of 150 to 10,000 and higher as well as organic nonionic surfactant monols having an average molecular weight of at least 300 and alcohol alkoxylates containing both water-soluble (polar) and oil-soluble (non-polar) groups (available under the trade name TERGITOL™).

Additional hydroformylation references, the teachings of which are incorporated herein by reference, include USP 4,243,818. When used, a precursor step that precedes step a. of the second aspect includes hydroformylation sufficient to functionalize or react with greater than zero percent of unsaturation in the starting material up to 100 percent of such unsaturation. The hydroformylation is preferably sufficient to react with at least (>) 20 percent (%) of unsaturation, more preferably > 50% of unsaturation and most preferably > 80% of unsaturation.

Still other references, the teachings of which are incorporated herein to the maximum extent permitted by law, that discuss hydroformylation include USP 4,423,162 (especially column 3, line 50 through column 4, line 36), USP 4,723,047, Canadian Patent Application (CA) 2,162,083, WO 2004/096744, USP 4,496,487, USP 4,216,343, USP 4,216,344, USP 4,304,945 and USP 4,229,562.

USPAP 2006/0193802, previously incorporated herein by reference, lists illustrative plant and vegetable seed oils in paragraph [0030]. Such oils include palm oil, palm kernel oil, castor oil, soybean oil, olive oil, peanut oil, rapeseed oil, corn oil, sesame seed oil, cottonseed oil, canola oil, safflower oil, linseed oil, sunflower oil; high oleic oils such as high oleic sunflower oil, high oleic safflower oil, high oleic corn oil, high oleic rapeseed oil, high oleic soybean oil and high oleic cottonseed oil; genetically-modified variations of oils noted in this paragraph, and mixtures thereof. Preferred oils include soybean oil (both natural and genetically- modified), sunflower oil (including high oleic) and canola oil (including high oleic). High oleic oils, especially high oleic oils with a 12 carbon atom and higher carbon number saturated hydrocarbon content within a range of from 0 percent by weight to 32 percent by weight, particularly less than 10 percent by weight, tend to have greater thermoxidative stability and lower pour points than their natural oil counterpart (e.g. high oleic sunflower oil versus natural sunflower oil).

USPAP 2006/0193802 also discusses reduction or hydrogenation of aldehydes (hydroformylated or formyl- substituted fatty acids or fatty acid esters) to alcohols in paragraph [0047]. In general, hydrogenation places formyl- substituted fatty acids and/or formyl-substituted fatty acid esters in contact with a source of hydrogen in the presence of a hydrogenation catalyst under conditions sufficient to convert the formyl-substituted acids and/or esters to an alcohol composition of hydroxymethyl-substituted fatty acids or fatty acid esters. Sources of hydrogen include pure hydrogen as well as hydrogen diluted with a non-reactive gas such as nitrogen, helium, argon or a saturated hydrocarbon. Hydrogenation catalysts typically comprise a metal selected from Group VIII, Group IB or Group IIB of the Periodic Table of the Elements noted above. Illustrative metals include Pd, Pt, Rh, Ni, copper (Cu), zinc (Zn) and mixtures thereof. The metal may be supplied as Raney metal or as supported metal on a suitable catalyst support, such as carbon or silica. Hydrogenation temperatures range from 50 ⁰C to 250 ⁰C. Hydrogenation pressures suitably range from 50 pounds per square inch gauge (psig) (345 kilopascals (kPa)) to 1,000 psig (6,895 kPa).

Capped polyester polyol lubricant compositions of the present invention comprise at least two ester moieties that are chemically linked one to another either directly or indirectly by way of an initiator moiety (also known as that portion of an initiator incorporated into the capped polyester polyol). The capped polyester polyol lubricant compositions have a number of characteristics or performance parameters that help skilled artisans match such compositions with desired lubricant applications.

Polyester polyol lubricant compositions of the present invention, like their capped analogues, comprise at least two ester moieties that are chemically linked one to another either directly or indirectly by way of an initiator moiety (also known as that portion of an initiator incorporated into the polyester polyol) and have characteristics or performance parameters that help skilled artisans match such compositions with desired lubricant applications

Compositions of the first aspect of the present invention, whether capped or not, may, and preferably do, include an initiator moiety other than a dendritic initiator moiety. Such compositions have a hydroxyl percentage that is preferably within a range of from 0.1 percent by weight (wt%) to 2 wt%, more preferably from 0.2 wt% to 1 wt% and, still more preferably, from 0.3 wt% to 0.7 wt%, each wt% being based upon composition weight. Compositions of the second aspect of the present invention, whether capped or not, preferably not capped, include a dendritic initiator moiety. Such compositions have a hydroxyl percentage that is preferably within a range of from 0.1 wt% to 31 wt%, more preferably from 10 wt% to 31 wt%, each wt% being based upon composition weight. Achieving a hydroxyl percentage of 0 percent by weight, while technically possible, is very expensive and, from a lubricity point of view, counter-productive. Lubricity is a complex function of viscosity and hydroxyl content and viscosity is, in turn, a function of molecular weight and hydroxyl percentage. As such, a hydroxyl content within the aforementioned ranges favorably affects both lubricity and viscosity and does so at a reasonable cost.

The compositions also have a 12 carbon atom and higher carbon number saturated hydrocarbon content that is preferably within a range of from 0 wt% to 32 wt%, more preferably from 0.1 wt% to 10 wt% and, still more preferably, from 0.2 wt% to 2 wt%, each wt% being based upon composition weight. As a general rule, a lower saturated hydrocarbon content is better than a higher saturated hydrocarbon content as composition pour point tends to increase with increasing saturated hydrocarbon content.

In addition, compositions of the first aspect have a viscosity at 25 ⁰C that is preferably at least 40 centipoises (cps) (0.04 pascal second (Pa.s)), more preferably at least 50 cps (0.05 Pa.s), still more preferably at least 75 cps (0.075 Pa.s) and even more preferably at least 100 cps (0.1 Pa.s) up to 2000 cps (2 Pa.s), more preferably up to 1500 cps (1.5 Pa.s), still more preferably up to 1000 cps (1 pascal Pa.s), and even more preferably, up to 800 cps (0.8 Pa.s). Further, the compositions of the first aspect have a pour point that is preferably -10 ⁰C or less, more preferably -20 ⁰C or less, still more preferably, -25 ⁰C or less and most preferably -30 ⁰C or less. The phrase "or less" means lower in temperature. For example -15 ⁰C is less than -10 ⁰C.

Compositions of the second aspect, by way of contrast, have a viscosity at 25 ⁰C that is preferably within a range of from 40 centipoises (cps) (0.04 pascal second (Pa.s)) to 8000 cps (8 Pa.s), more preferably from 1000 cps (1 Pa.s) to 7800 cps (7.8 pascal Pa.s), and, still more preferably, from 50 cps (0.05 Pa.s) to 7500 cps (7.5 Pa.s). Further, the compositions of the first aspect have a pour point that is preferably -5 ⁰C or less, more preferably -7 ⁰C or less. Skilled artisans recognize that composition pour point may be modified by addition of conventional pour point depressants such as polyalkylmethacrylates and styrene/maleic anhydride interpolymers. Skilled artisans also recognize that pour point depressant amounts in excess of about 2 wt%, based upon total composition weight (including the pour point depressant) typically yield minimal further improvement in pour point, but do increase composition cost.

The compositions have a viscosity index or VI, determined as detailed below, that preferably lies above 120, more preferably above 140 and, still more preferably, above 150. VFs in excess of 400, while known, are rare. Skilled artisans recognize that VI indicates how a lubricant viscosity changes with temperature. For example, a low VI (e.g. 100) suggests that fluid viscosity will vary considerably when it is used to lubricate a piece of equipment that operates over a wide range of temperatures, such as from 20 ⁰C to 100 ⁰C. Skilled artisans also recognize that as VI increases, lubricant performance also tends to improve. Based upon that recognition, skilled artisans prefer higher VI values (e.g. 150) over lower VI values (e.g. 100). For purposes of comparison, typical lubricant VI ranges are as follows: mineral oils = 95 to 105; polyalphaolefins = 120 to 140; synthetic esters = 120 to 200 and polyalkylene glycols = 170 to 300.

The polyester polyol lubricant compositions of the present invention, whether capped or not, need not, but preferably do, include an initiator moiety that links at least two ester moieties. The initiator moiety of compositions of the first aspect of the present invention derives from the initiator used in the method of the second aspect of the present invention. The initiator, when present, has at least two reactive sites, preferably pendant or terminal hydroxyl groups that react with a portion of an alkanolyzed, hydroformylated and reduced seed oil, preferably a reactive ester portion of said alkanolyzed, hydroformylated and reduced seed oil. When making capped polyester polyol lubricant compositions, the capping agent reacts, in turn, with the same portion or a different portion of the alkanolyzed, hydroformylated and reduced seed oil.

Suitable initiators, from which initiator moieties are derived, may be represented by a formula R-(OH)_n, where R is a linear alkyl, a branched alkyl, or a cyclic alkyl moiety, and n is an integer within a range of from 0 to 64, preferably from 1 to 64, with very satisfactory results being obtained when n is an integer selected from a group consisting of 2, 3, 6, 12, 16, 32 and 64. Especially preferred results follow when n is an integer within a range of from 1 to 32, preferably an integer selected from a group consisting of 2, 3, and 6 for compositions of the first aspect or an integer selected from a group consisting of 12, 16, 32 and 64 for compositions of the second aspect. R preferably contains from 1 to 6 carbon atoms (C₁-C_O), more preferably from 1 to less than 6 carbon atoms. One may also think of "n" in the formula R-(OH)_n as representing a number of reactive sites. If no initiator moiety is present in the capped polyester polyol lubricant compositions of the first aspect or the polyester polyol lubricant compositions of the second aspect and no initiator is used in the method of the third or fourth aspects, n effectively equals zero. Suitable initiators include, but are not limited to, one or more of neopentyl glycol (NPG), butane diol, hexane diol, cyclohexane diol, isomers of cyclohexane diol, isomers of cyclohexane dimethanol, hydroquinone bis(2-hydroxyethyl)ether, glycerin, ethoxylated glycerin (e.g. IP-625, commercially available from The Dow Chemical Company), trimethylolpropane, sorbitol, hyperbranched or dendritic base products commercially available from Perstorp under the trade designation BOLTORN®. For example BOLTORN® H20 has a n value of 16 and a nominal weight average molecular weight (M_w) of 1,750; BOLTORN® H2003 has a n value of 12 and M_w of 2,300; BOLTORN® H2004 has a n value of 6 and M_w of 3,100; BOLTORN® H30 has a n value of 32 and a M_w of 3,600; and BOLTORN® H40 has a n value of 64 and a M_w of 7,300. The present invention need not be limited to any particular initiator and skilled artisans can readily select suitable initiators that yield performance comparable to those specifically identified herein.

In column 1, lines 21-55, USP 6,627,720 (Campbell et al.) discusses "hyperbranched polymers", describing them as materials consisting of highly branched polymer chains that often contain a large number of reactive groups which may be useful for further reactions to produce a finished product. An important property of hyperbranched polymers is their low viscosity relative to less highly branched polymers of similar molecular weight.

Campbell et al. notes that hyperbranched polymers may be classified as either dendrimers or random hyperbranched polymers. Dendrimers originate from a central location, with branching occurring as the polymer grows outward, leading to structures of relatively high symmetry. Tight control of reaction conditions and stoichiometry is required to produce dendrimers. Random hyperbranched polymers are more readily accessible from standard polymerization reactions. Campbell et al. teaches that methods employed for production of random hyperbranched polymers usually entail a separate post-polymerization step of reacting functional groups present on different polymer chains to create the branches.

If desired, polyester polyol lubricant compositions of the present invention, whether capped as in the first aspect on uncapped as in the second aspect, may be augmented by an amount of one or more of the seed or vegetable oils disclosed herein. When present in a lubricant composition, such seed or vegetable oils typically constitute an amount within a range of from 1 wt% to 90 wt%, preferably from 10 wt% to 80 wt% and more preferably from 30 wt% to 70 wt%, in each instance based upon combined weight of capped polyester polyol lubricant composition and seed or vegetable oil. The methods of the third and fourth aspects of the present invention include a catalyst as part of the reaction mixture. The catalyst tends to lower activation energy and increase esterification/transesterification reaction rates. Both acids and bases may be used as catalysts. Illustrative catalysts include, but are not limited to, Tin II catalysts such as stannous bis(ethylhexoate); Tin IV-based catalysts such as tin octanoate, dibutyl tin dilaurate, butylstannoic acid, and dibutyl tin oxide; soluble mineral acids; sodium carbonate; metal alkoxides (e.g. sodium methoxide, potassium methoxide, titanium propoxide or titanium isopropoxide); sodium hydroxide; potassium hydroxide; sodium carbonate; potassium carbonate; boron trifluoride; and zinc dichloride. Other well known catalysts for direct polyesterification are based on antimony, germanium, and titanium, especially for higher temperatures. Analytical Procedures

Determine kinematic viscosity, in centistokes (cSt) and its metric equivalent, square meters per second (m²/sec) at 40 ⁰C and 100 ⁰C using a Stabinger viscometer in accord with American Society for Testing and Materials (ASTM) D7042. Use the kinematic viscosities to calculate a VI in accord with ASTM D2270.

Measure lubricant pour point in accord with ASTM D97-87.

Use Thermo-Gravimetric Analysis (TGA) to assess thermo-oxidative stability of lubricant materials. TGA assessment includes heating a lubricant sample at a rate of 10 ⁰C per minute in flowing air and record lubricant weight loss versus temperature for two percent (2%) weight loss, 5% weight loss and 50% weight loss.

Measure dynamic friction coefficient using an Optimol SRV (Schwingungen Reibung Verschliess) friction apparatus comprising a steel plate and an oscillating steel ball. Place three drops of a candidate lubricant fluid on the plate, position the ball atop the plate, but disposed within the three drops of candidate fluid. For a test duration of one hour, apply a load of 200 Newtons (N) to the ball and perpendicular to the plate and use an oscillation frequency (of the ball on the plate) of 50 hertz and an oscillation distance of one millimeter (1 mm). Determine SRV friction coefficient at 30 ⁰C and 60 ⁰C.

Use the same apparatus, oscillation frequency, oscillation distance and temperatures, but start with an applied load of 50 N and increase the load by 100 N each minute until one reaches a failure load. "Failure load" or "failure limit" equals an applied load at which the candidate fluid "breaks" (undergoes a sharp increase in friction coefficient). Report results as the maximum load applied to the ball before the fluid breaks.

Use a FALEX™ 4-ball thrust washer testing instrument (Model TW80) to evaluate candidate fluids for wear scar and coefficient of friction (COF) determination) in accord with ASTM D5183-95. Test parameters for fluid evaluation include a test time of 60 minutes, a speed of 1200 revolutions per minute (rpm) and an applied load of 90 pounds (40.9 kilograms (kg)). Use a load cell to measure torque. After testing, use a microscope equipped with an eyepiece verticule to measure wear scar length. Calculate coefficient of friction (COF) by multiplying a machine dependent constant of 5.67 times a quotient determined by dividing measured torque by applied load. Examples The following examples illustrate, but do not limit, the present invention. All parts and percentages are based upon weight, unless otherwise stated. All temperatures are in °C. Examples (Ex) of the present invention are designated by Arabic numerals and Comparative Examples (Comp Ex) are designated by capital alphabetic letters. Unless otherwise stated herein, "room temperature" and "ambient temperature" are nominally 25 °C. General Procedure for Preparing Hydroformylated and Reduced Fatty Acid Methyl Ester A, Fatty Acid Methyl Ester Hvdroformylation

Prepare a catalyst solution by dissolving, with stirring, 0.078 grams (g) of dicarbonylacetonato rhodium and 0.751 g of dicyclohexyl-(3-sulfonoylphenyl)phosphine mono-sodium salt in 53.893 g of n-methyl-2-pyrrolidinone under a nitrogen atmosphere. Transfer 11.06 g of the catalyst solution to a nitrogen purged 100 ml stainless steel autoclave. Pressurize the autoclave to a pressure setting of 200 psig (1,379 kPa) with synthesis gas (a 1:1 molar ratio of gaseous hydrogen and carbon monoxide) and heat contents of the autoclave, with agitation using a mechanical stirrer operating at a rate of 700 revolutions per minute (rpm), to a temperature of 90 ⁰C and maintain that temperature for a period of 15 minutes. With continued stirring at the 90 ⁰C temperature, add 38.98 g of a mixture of soy methyl esters (11 wt% methyl palmitate, 4 wt% methyl stearate, 25 wt% methyl oleate, 52 wt% methyl linoleate and 8 wt% methyl linolenate, each weight percent being based upon total mixture weight). Add sufficient fresh synthesis gas to pressurize the autoclave to a pressure setting of 400 psig (2,758 kPa). Maintain contents of the reactor at the 90 ⁰C temperature with stirring and under the pressure setting of 400 psig (2,758 kPa) for a period of 22.5 hours to yield an aldehyde product composition (a conversion of mixed methyl esters to aldehydes of 84%).

Analyze sample quantities (lμl sample injection volumes of 1:1 dilutions in diglyme) of the aldehyde product composition against diglyme as an internal standard via gas chromatography (GC) using a HP 6890 GC with a DB-5 capillary column and a flame ionization detector (FID). Direct calibration (by injection of known concentrations of standard materials) provides response factors for the following components: methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, methyl formylstearate. Determine response factors for dialdehyde and trialdehyde components of the aldehyde product composition by hydroformylating a set volume of a natural product distribution of unsaturated fatty acid methyl esters. Using the response factor of the known monoaldehyde response factor (from hydroformylating methyl oleate), determine response factors of the dialdehyde and trialdehyde based on their respective integrated signal intensities and the mass difference with the known monoaldehyde sample content. The estimated error using this technique is + 1% for the dialdehyde and + 20% for the trialdehyde.

Determine dimer and heavy concentrations by diluting a sample (lμl sample injection volumes of 1:1 dilutions in diglyme) of the aldehyde product composition and subjecting the diluted sample to GC analysis using a HP 6890 GC and a ZB-I capillary column run over a temperature range of from 100 ⁰C to 350 ⁰C at a rate of temperature increase of 40⁰C per minute in conjunction with a FID. Split a chromatogram from the GC analysis into two regions, a products region and a heavies region, then use a "Normalized Area Percent" method by which the GC determined peak area of a compound of interest is divided by a sum of all peak areas evolved from the sample. As used herein, "heavies" refers to compounds that have a mass in excess of that of a C₂o ester. Compare a sum of areas under GC peaks for methyl oleate, methyl linoleate, and methyl linolenate before and after hydroformylation to determine percent conversion.

The aldehyde composition contains 14 wt% saturates (palmitate, and stearate), 14 wt% unsaturated materials (e.g. unreacted methyl oleate and methyl linoleate), 40 wt% monoaldehyde, 30 wt% dialdehyde, 1.8 wt% trialdehyde, and 0.2 wt% heavies, each wt% being based upon total aldehyde product composition weight.. B. Hydro genation

Pack an up-flow tubular reactor with a commercial supported nickel catalyst (440 ml, Sud-Chemie C46-8-03). The reactor has an inlet that comprises two liquid feeds and one gas feed that come together before entering the reactor. A first liquid feed consists of a hydroformylated soy methyl ester mixture (e.g. the aldehyde composition prepared in accord with "A. Fatty Acid Methyl Ester Hydroformylation" detailed above or a mixture comprising 15 wt% saturates, 36 wt% monoaldehyde, 46 wt% dialdehyde, and 2 wt% trialdehyde, each wt% being based on first liquid feed weight). A second liquid feed consists of a recycle stream from hydrogenation of the hydrdoformylated soy methyl ester mixture. The first liquid feed enters the reactor at a flow rate of 5 grams per minute (g/min). The second liquid feed enters the reactor at a flow rate of 19 g/min. The two liquid feeds combine to provide a total Liquid Hourly Space Velocity of 3.51 hr ¹. Feed gaseous hydrogen to the reactor at a rate of 2,000 standard cubic centimeters per minute (seem) (equivalent to a Gas Hourly Space Velocity of 272 hr^"1), then heat reactor contents to a set point temperature of 143 ⁰C while maintaining pressure within the reactor at a set point pressure of 830 pounds per square inch gauge (psig) (5,723 kPa) for a period of time determined by the desired functionality of the resulting methyl hydroxyl functionalized fatty acid esters to convert the aldehyde product composition to an alcohol product composition. Dilute sample quantities (10 microliters (μl) injection volume of 1:20 dilution in dioxane) and analyze the dilute sample quantities against an internal diglyme standard using the same apparatus as used for analysis of the aldehyde product composition. Determine response factors by direct calibration for methyl palmitate, methyl stearate, methylformylstearate, and methyl hydroxymethyl stearate. Determine response factors for other components of the aldehyde product composition (e.g. dialdehydes and trialdehydes) using the same procedure as outlined above under A. Hydroformylation. Calculate percent conversion by comparing methyl formyl stearate peak area before and after hydrogenation.

Determine dimer and heavy concentrations using the same procedure as outlined above for determination of like concentrations in the aldehyde product composition. Analysis of the alcohol product composition shows that it contains 19.2 wt% saturates, 35.6 wt% mono-ol, 38.8 wt% diol, 3.3 wt% triol, 2.6 wt% dimer heavies, 0.2 wt% lactones, and 0.3 wt% ethers, each wt% being based upon total alcohol product composition weight. C. Saturate Removal Removal of at least a portion of saturates from the product constitutes a preferred embodiment of the present invention. While various saturate removal techniques may be used, a preferred route involves feeding a product stream to a wiped film evaporator. Skilled artisans recognize that level of component removal, in this case saturate removal, involves an interplay of a number of factors, primarily pressure, flow rate and evaporator jacket temperature. Skilled artisans also recognize that a small scale or laboratory scale apparatus may, and often does have operating parameter limitations not present in much larger scale, including commercial scale, apparatus of the same general type, e.g. wiped film evaporator. For a two inch (5.1 centimeter (cm)) wiped film evaporator (DSL-5 UIC GmbH), the factors include a jacket temperature of from 90 ⁰C to 150 ⁰C, preferably 110 ⁰C, a product flow rate of 0.3 kilograms per hour (kg/hr), and a reduced pressure of from 0.01 millimeters of mercury (mm hg) to 1 mm Hg, preferably from 0.1 mm Hg to 0.3 mm Hg. With a larger scale apparatus, the jacket temperature may increase to as much as 300 ⁰C, provided one increases product flow rate to the apparatus and/or alters pressure in a manner sufficient to limit product heat history within the apparatus to a level below that which yields unacceptable amounts of unwanted byproducts such as heavies while still effecting a desirable level of saturate removal. Skilled artisans readily understand how to modify the factors based upon change of scale without undue experimentation. Output from the wiped film evaporator, irrespective of scale, has a reduced saturate content relative to that found in the product stream fed to the wiped film evaporator. If the saturate content remains above that desired for further processing, simply replicate use of the wiped film evaporator one or more times, but use output from a prior pass through the wiped film evaporator as the heated stream fed to the wiped film evaporator in order to further reduce saturate content. If desired, separate mono-hydroxyl fatty acid methyl esters from a saturate-depleted stream using the same apparatus and procedure save for increasing the temperature to 150 ⁰C.

Even though the aforementioned process begins with a commercial methyl ester product, skilled artisans recognize that one may produce a mixture of alkyl esters, preferably a mixture lower alkyl (one to four carbon atoms (C₁ to C₄)) esters and more preferably a mixture of methyl esters by subjecting a seed oil to conventional alkanolysis procedures using, for example, methanol. Such a mixture of alkyl esters, preferably methyl esters, readily substitutes for the commercial product without undue experimentation. Examples 1-7 Fit a 2 liter (L), three-necked, round bottom glass flask with a water cooled condensing column in one opening or neck, and a gaseous nitrogen (N₂) inlet in a second opening or neck. Either fit a third opening with a gas tight sealed mechanical stirrer or, when using a magnetic stirrer, a plug. Cap the condensing column's top with a gas outlet fitting to allow the N₂ gas to bubble out through a mineral oil filled bubbler and provide an approximate quantification of sweep gas flow rate through the flask.

Add a polyol initiator, a hydroformylated and reduced seed oil derived fatty acid methyl ester, and a short chain fatty acid methyl ester or short chain fatty acid to the flask together with an amount of catalyst (See Table 2). The catalyst is either dibutyl tin dilaurate (DBTL), a tin IV (Sn (IV)) catalyst or tin octoate, a Sn (II) catalyst. Heat flask contents with stirring to a temperature within a range of from 160 ⁰C and

200 ⁰C to effect a reaction among flask contents. Trap methanol (when using a short chain fatty acid methyl ester as a reactant) or water (when using a short chain fatty acid as a reactant) that evolves from the heated and stirred flask contents in a receiver flask connected inline between the condenser and the bubbler by way of an overhead adapter with a cooling condenser (sometimes called a "short-path distillation adapter").

Periodically collect samples of the reacting mixture and measure product molecular weight (number average (M_n), weight average (M_w) and z-average (M₂)) by gel permeation chromatography and calculate molecular weight distribution (MWD or M_w/M_n). Upon the first to occur of (a) sample molecular weight reaching a molecular weight range determined to result in a typical lubricant viscosity and (b) molecular weight increase falling below 0.5%/hour, terminate the reaction. Determine product hydroxyl (OH) content was measured by Fourier Transform Infra-Red (FTIR) spectroscopy using OH resonance absorption between 3300 reciprocal centimeters (cm ¹) and 3600 cm^"1 calibrated with a series of similar polyols that have their OH content measured in accord with ASTM D4273-83. The standard polyols have hydroxyl percentages as follows: 0.36%, 0.75%, 1.7% and 2.0%. FTIR absorbance is linear over a range comprising the foregoing hydroxyl percentages when determined in accord with ASTM D4273-83 using 0.996 as a square of the correlation coefficient. An alternate technique involves determining hydroxyl number via titration in accord with ASTM D4274- 05 (sometimes called "phthalic anhydride method"). Measure product viscosity via one of two techniques. One technique uses a

Brookfield Viscometer using a #3 nozzle at 50 rpm. A second technique uses timed flow through a standard funnel (NALGENE™ model 4260-0020 polyethylene funnel with a top inner diameter (ID) of 52 mm, a stem length of 21 mm, and a drain time of 8.0 cps/sec calibrated versus standard silicone liquids. A square of the correlation coefficient of viscosity versus drain time for this method is = 0.992).

Table 1 below provides composition information for alkanolyzed, hydroformylated and reduced seed oils used as reactants. Prepare monomers (alkanolyzed, hydroformylated and reduced seed oils) using methanolysis procedures noted above in conjunction with the "General Procedure for Preparing Hydroformylated and Reduced Fatty Acid Methyl Ester" detailed above. Monomers A, B, C and F begin with NATREON™ high oleic sunflower oil whereas monomers D and G begin with soybean oil and monomer E begins with NATREON™ high oleic canola oil. Monomers A, B, C, D and G all have reduced saturate levels as a result of saturate removal using the procedure detailed above. Monomers E and F have unreduced saturate levels due to omission of the saturate removal step. NATREON is a tradename of Dow AgroScience.

Table 2 below provides composition information relative to contents of the flask for each Ex. Ex 1 and 3 through 7 use NPG as an initiator. Ex 2 uses no initiator. Ex 1-2 and Ex 4-7 use DBTL as a catalyst and Ex 3 uses tin octanoate as the catalyst. Ex 1-2 and 5-7 use short chain (Cs-C₁O) methyl esters (commercially available from Peter Cremer NA under the trade designation ME C8-10) as a capping agent and Ex 3-4 use short chain (Cs-C_1O) fatty acids commercially available from Peter Cremer NA under the trade designation FA C8-10 as the capping agent. Table 3 below summarizes select reaction product physical properties and performance measures for each of Ex 1-7. Table 3 shows viscosity measurements at 25 ⁰C.

*hydroformylated and reduced methyl esters from NATREON Canola seed oil. **hydrofomylated and reduced methyl esters from NATREON Sunflower seed oil. + includes cyclic ethers, lactones and homopolymerized species

Table 2. Flask Contents

Table 3. Physical Properties and Performance Parameters

— means not measured

The data presented in Tables 2 and 3 show that lubricant compositions of the present invention are capable of functioning as base fluids with very good lubricant properties. The lubricant compositions show very good properties independent of the seed oil source and with or without an alcohol initiator. Examples 1-4 and 7 show extremely low pour points, significantly lower than seed or vegetable oils which typically have a pour point within a range of from 0⁰C to -20⁰C. Pour points of -30⁰C and below (e.g. -36°C) have particular utility as lubricants for apparatus that operate in very cold climates with extended periods of temperatures below -20⁰C. Furthermore, the data show that lubricant composition pour point temperature is a function of composition saturated stearate content and that by reducing such saturated stearate content, one also reduces composition pour point temperature. In addition, Ex 1-4 have VI values in excess of 160. Typical mineral oil products, on the other hand, typically have VI values within a range of from 95 to 105. As noted above, skilled artisans prefer higher VI values over lower VI values. Skilled artisans particularly desire higher VI values for operating industrial and automotive equipment and consider values in excess of 150 to be especially desirable.

Wear scar data in Table 3 also demonstrate that these lubricants have excellent film forming properties, with lubricants that provide wear scars of less than 0.70 mm being considered as good lubricants. COF data support characterization as good lubricants (COF less than 0.13 for good and less than 0.10 for excellent). Ex 8

Prepare an initiator blend of 12.08 g (20 millimoles (mmol) of ethoxylated glycerin (IP-625, The Dow Chemical Company) and 2.2 g (20 mmol) of a hydroxyl terminated dendritic initiator (commercially available under the trade designation BOLTORN® H-20 from Perstorp), having 16 terminal hydroxyl groups, using a molar ratio of 16:1 for IP- 625:BOLTORN H-20. Charge the ethoxylated glycerin and hydroxyl terminated dendritic initiator into a clean, dry, 3-neck 250-ml glass round bottom flask, equipped with a magnetic stir bar and rubber septum. Equip one neck of the flask, nominally an "outlet neck" with a short-path condenser running 50 ⁰C water from a recirculating bath unit, to prevent buildup of saturates. Use a needle to introduce a nitrogen atmosphere to the flask via the septum. Seal and degas the flask under a vacuum of 20 Torr (266.6 pascals (Pa) while heating flask contents to 50 ⁰C. Heat flask contents, with continued stirring, to a temperature of 150 ⁰C using a temperature moderated oil bath with external feedback while maintaining a constant flow of gaseous nitrogen and hold the flask contents at that temperature for a period of one hour.

After the one hour period, add 187 g of a soy monomer mixture (see Table 4 below for composition) to heated and stirred flask contents via an addition funnel, maintaining the nitrogen flow during the addition. Heat flask contents, with continued stirring and under a nitrogen flow, to a temperature of 150 ⁰C and maintain that temperature for an additional period of 30 minutes before adding 0.1 g of dibutyl tin oxide (DBTO) as a catalyst and heating flask contents to a temperature of 190 ⁰C whereupon methanol (MeOH) quickly begins to evolve.

Maintain contents of the flask under nitrogen with continued stirring at the 190 ⁰C temperature for a period of five hours. Cool contents of the flask to a temperature 50 ⁰C. Distillate from the flask is a clear, colorless liquid (methanol or MeOH) with a small amount of white solid. Contents of the flask comprise a reaction product that has a hydroxyl content of 30.2 percent and a M_n of 3363.

Table 4

Ex 9

Replicate Ex 8, but increase hydroxyl terminated dendritic initiator content to 4.4 g (2.5 mmol) to provide a molar ratio of 8:1 for IP- 625: B OLTORN H20. The reaction product has a hydroxyl content of 10.4 percent, a M_n of 5505, a viscosity (at 25 ⁰C) of 7428 cps (7.4 Pa.s), and a pour point of -8 ⁰C. Ex IO

Replicate Ex 8, but increase hydroxyl terminated dendritic initiator content to 8.8 g (5 mmol) to provide a molar ratio of 4:1 for IP- 625: B OLTORN H20. The reaction product has a hydroxyl content of 23.9 percent, a M_n of 4152, a viscosity (at 25 ⁰C) of 4316 cps (4.3 Pa.s), and a pour point of -7 ⁰C. Ex I l

Replicate Ex 8, but increase hydroxyl terminated dendritic initiator content to 8.8 g (5 mmol) and decrease ethoxylated glycerin content to 6.04 g (10 mmol) to provide a molar ratio of 2:1 for IP- 625: B OLTORN H20. The reaction product has a hydroxyl content of 30.4 percent and a M_n of 3179.

The data presented in Ex 8-11 relate to use of hyperbranched polyol initiators, specifically engineered molecules commercially available from Perstorp under the trade name BOLTORN. The reaction products of Ex 8-11, while not fully optimized for pour point and viscosity, function as polyester polyol lubricant compositions and demonstrate that such engineered molecules, when used in conjunction with a phase compatibilizer such as IP-625, have utility in making such capped polyester polyol lubricant compositions. Ex 12

Replicate Ex 1 with several changes. First, apply a vacuum of 10 torr (1333.2 pascals (Pa) to contents of the flask during heating to effect a reaction among flask contents. The vacuum effects removal of volatile condensation products (primarily methanol) produced during the reaction among flask contents. Second, change the alkanolyzed, hydroformylated and reduced seed oil to a composition as shown in Table 5 below. Third, change type and amount (580.26 g) of capping agent. The capping agent is a mixture of 4.29 wt% C₆ methyl ester, 52.88 wt% C₈ methyl ester and 42.03 wt% C₁₀ methyl ester (commercially available from Peter Cremer N.A. under the trade designation ME810), each wt% being based upon mixture weight. Fourth, add 733.8 g of ethoxylated glycerin (weight average molecular weight of 625, commercially available from The Dow Chemical Company under the trade designation IP™ 625) as an initiator.

Table 5

The product has a weight average molecular weight of 1200, a viscosity at room temperature (nominally 25°C) of 207 cps (0.21 Pa.s), a %OH of 0.36%, a wear scar of 0.67 mm, a COF of 0.024, a pour point of -3°C, and a viscosity index (VI) of 179.

Ex 12 shows that a capped polyester polyol lubricant composition representative of the present invention provides desirable lubricity properties based upon a small wear scar and a low COF.

Claims

CLAIMS:

1. A capped polyester polyol lubricant composition, the composition comprising at least two ester moieties, the ester moieties optionally being chemically linked one to another either (a) directly, or (b) indirectly by way of an initiator moiety, said composition also having a hydroxyl percentage within a range of from 0.1 percent by weight to 2 percent by weight, each percent by weight being based upon composition weight, and a 12 carbon atom and higher carbon number saturated hydrocarbon content within a range of from 0 percent by weight to 32 percent by weight, each percent by weight being based upon composition weight, a viscosity at 25° centigrade within a range of from 40 centipoise to 2000 centipoise, and a pour point of - 10° centigrade or less.

2. A polyester polyol lubricant composition, the composition comprising a plurality of ester moieties, the ester moieties being chemically linked one to another directly or indirectly by way of a dendritic initiator moiety, the dendritic initiator moiety being derived from dendritic base products or an alkoxylated version thereof, and a hydroxyl percentage within a range of from 0.1 percent by weight to 31 percent by weight, each percent by weight being based upon composition weight, and a 12 carbon atom and higher carbon number saturated hydrocarbon content within a range of from 0 percent by weight to 32 percent by weight, each percent by weight being based upon composition weight, a viscosity at 25° centigrade within a range of from 40 centipoise to 8000 centipoise, and a pour point of - 5° centigrade or less.

3. The composition of Claim 1 or Claim 2, wherein the initiator moiety is represented by a formula R-(OH)_n, where R is n-alkyl, a branched alkyl, or a cyclic alkyl moiety, and n is an integer within a range of from 1 to 64.

4. The composition of Claim 3, wherein n is an integer selected from a group consisting of 2, 3, 6, 12, 16, 32 and 64.

5. The composition of Claim 3, wherein the alkyl moiety contains from one carbon atom to six carbon atoms.

6. The composition of Claim 1, wherein the intitiator moiety derives from an initiator selected from a group consisting of neopentyl glycol (NPG), butane diol, hexane diol, cyclohexane diol, isomers of cyclohexane diol, isomers of cyclohexane dimethanol, hydroquinone bis(2-hydroxyethyl)ether, glycerin, trimethylolpropane, sorbitol, dendritic base products, and alkoxylated versions of members of the group.

7. The composition of Claim 1 or Claim 2, wherein the saturated hydrocarbon content is within a range of from 0.1 percent by weight to 10 percent by weight.

8. The composition of Claim 1 or Claim 2, wherein one of the ester moieties is an ester alcohol or a capping agent, the capping agent being a methyl ester of a short chain (C_O-C₁₂) fatty acid or a short chain (C_O-C₁₂) fatty acid.

9. The composition of Claim 8, wherein the ester alcohol is an alkanolized, hydroformylated and reduced seed oil, the seed oil being at least one of a natural oil, a high oleic oil or a genetically modified oil wherein the oil is selected from a group consisting of castor oil, soybean oil, olive oil, palm oil, palm kernel oil, peanut oil, rapeseed oil, corn oil, sesame seed oil, cottonseed oil, canola oil, safflower oil, linseed oil, and sunflower oil.

10. A method of preparing a polyester polyol lubricant composition, which method comprises: a. subjecting a reaction mixture that comprises an alkanolyzed, hydroformylated and reduced seed oil, a capping agent, a catalyst and, optionally, an initiator to an elevated temperature within a range of from 170° centigrade to 200° centigrade to convert at least a portion of the reaction mixture to a capped polyester polyol and a volatile byproduct; and b. concurrently removing at least a portion of the volatile byproduct.

11. The method of Claim 10, further comprising a plurality of sequential precursor steps to prepare the alkanolized, hydroformylated and reduced seed oil, the sequential precursor steps comprising, in order: al. alkanolizing a seed oil to convert glycerides present in the seed oil to a mixture of saturated and unsaturated fatty acid esters of the alkanol, the alkanol having a straight-chain or branched structure and containing from 1 to 15 carbon atoms; a2. hydroformylating the mixture of saturated and unsaturated fatty acid esters to convert said mixture to an aldehyde or mixture of aldehydes; and a3. reducing the aldehyde or mixture of aldehydes in a hydrogen atmosphere with assistance of a hydrogenation catalyst to convert said aldehyde or mixture of aldehydes to an alcohol composition of hydroxymethyl-substituted fatty acids or hydroxymethyl- substituted fatty acid esters.

12. The method of Claim 11, wherein step a2. occurs in a non-aqueous reaction medium together with a solubilized Group VIII transition metal-organophosphine ligand complex catalyst, optionally with a solubilized free organophosphine metal salt ligand.

13. The method of Claim 10, wherein the capping agent is methyl ester of a short chain (C_O-C₁₂) fatty acid or a short chain (C_O-C₁₂) fatty acid.

14. The method of Claim 10, wherein the catalyst is selected from a group consisting of stannous bis(ethylhexoate), tin octanoate, dibutyl tin dilaurate, butylstannoic acid, dibutyl tin oxide, metal alkoxides, soluble mineral acids, sodium carbonate, sodium hydroxide, potassium carbonate, potassium hydroxide, boron trifluoride, and zinc dichloride., the metal alkoxide being selected from a group consisting of sodium methoxide, potassium methoxide, titanium propoxide or titanium isopropoxide.

15. The method of Claim 10, wherein the initiator is represented by a formula R- (OH)_n, where R is n-alkyl, a branched alkyl, or a cyclic moiety, and n is an integer within a range of from 1 to 64.

16. The method of Claim 10, wherein the initiator is selected from a group consisting of neopentyl glycol (NPG), butane diol, hexane diol, cyclohexane diol, isomers of cyclohexane diol, isomers of cyclohexane dimethanol, hydroquinone bis(2- hydroxyethyl)ether, glycerin, trimethylolpropane, sorbitol, dendritic base products, and alkoxylated versions of the aforementioned materials

17. The method of Claim 10, wherein the seed oil being at least one of a natural oil, a high oleic oil or a genetically modified oil wherein the oil is selected from a group consisting of castor oil, soybean oil, olive oil, peanut oil, rapeseed oil, corn oil, sesame seed oil, cottonseed oil, canola oil, safflower oil, linseed oil, and sunflower oil.

18. A method for removing at least a portion of saturates from the capped polyester polyol lubricant composition of Claim 1 or the polyester polyol lubricant composition of Claim 2, which method comprises feeding a heated feedstream, the feed stream being the capped polyester polyol lubricant composition or the polyester polyol lubricant composition, to a wiped film evaporator that operates under a reduced pressure to separate the feed stream into a saturate-rich portion and a saturate-depleted remainder.

19. The method of Claim 18, wherein the feedstream is heated to a temperature within a range of from 90 degrees centigrade to 150 degrees centigrade, and the reduced pressure is within a range of from 0.01 millimeters of mercury to 1 millimeters of mercury.

20. The method of Claim 18 or Claim 19, wherein the saturate-depleted stream from one pass through the wiped film evaporator is used as the heated feedstream for a subsequent pass through the wiped film evaporator, thereby further reducing saturate content of the saturate-depleted stream.