WO2008089130A1

WO2008089130A1 - Lubricant compositions and methods of making same

Info

Publication number: WO2008089130A1
Application number: PCT/US2008/050988
Authority: WO
Inventors: Martin R. Greaves
Original assignee: Dow Global Technologies Inc.
Priority date: 2007-01-17
Filing date: 2008-01-14
Publication date: 2008-07-24
Also published as: JP2010516839A; EP2121805A1; BRPI0806223A8; JP5270577B2; US20100009877A1; ATE556104T1; US8247501B2; CN101622294B; BRPI0806223A2; EP2121805B1; CN101622294A; BRPI0806223B1

Abstract

Compositions are described that include a) from 15 weight percent to 60 weight percent of one or more random alkylene oxide interpolymers, each having a weight average molecular weight ranging from 250 g/mol to 2000 g/mol and comprising from 30 weight percent to 60 weight percent of polymer units derived from ethylene oxide; and b) from 40 weight percent to 85 weight percent of one or more alkylene oxide block interpolymers, each having a weight average molecular weight ranging from 1500 g/mol to 4000 g/mol and comprising from 40 weight percent to 90 weight percent propylene oxide blocks. The compositions have a first viscosity in the absence of water and a second viscosity that is at least 60 percent of the first viscosity when at least 10 weight percent water is present. Methods of lubricating surfaces, particularly, marine bearing surfaces with such compositions, are also described.

Description

LUBRICANT COMPOSITIONS AND METHODS OF MAKING SAME

PRIOR RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 60/880,743 filed January 17, 2007.

FEDERALLY SPONSORED RESEARCH STATEMENT

[0002] Not applicable.

REFERENCE TO MICROFICHE APPENDIX [0003] Not applicable.

FIELD OF THE INVENTION [0004] Embodiments of the invention generally relate to lubricant compositions.

Specifically, embodiments of the invention relate to lubricant compositions suitable for use as stern tube lubricants in ocean-going and other marine vessels.

BACKGROUND OF THE INVENTION

[0005] Lubricants are widely used in the marine industry to lubricate the bearings of various ship assemblies, particularly bearings in stern drives. Compositions that are suitable for such uses should have certain minimum properties to be useful. First, they should have a viscosity that provides acceptable lubrication over a wide temperature range. Another important property for such lubricants is their ability to maintain lubricity in the presence of up to about 50 weight percent water, especially sea water. As more and more ships travel the oceans and other waterways, lubricants should also be biodegradable. Some formulated conventional lubricant compositions meet one or more of these standards. But when such conventional lubricant compositions leak from a ship's stern drive assembly, they cause a sheen on the surface of water thereby implying a pollution hazard even when the lubricant composition is biodegradable. Thus, compositions that balance suitable lubricant properties, maintain those properties in the presence of water, and form reduced amounts of sheen on the surface of water would be useful. SUMMARY EMBODIMENTS OF THE INVENTION

[0006] Embodiments of the invention provide a polymer composition that includes a) from 15 weight percent (wt. percent or wt.%) to 60 wt. percent, based upon composition weight, of one or more random alkylene oxide interpolymers, each of which has a weight average molecular weight (M_w) ranging from 250 grams per mole (g/mol) to 2000 g/mol and comprises from 30 wt. percent to 60 wt. percent, based upon random interpolymer weight, of polymer units derived from ethylene oxide; and b) from 40 wt. percent to 85 wt. percent, based upon composition weight, of one or more alkylene oxide block interpolymers, each of which has a M_w ranging from 1500 g/mol to 4000 g/mol and comprises from 40 wt. percent to 90 wt. percent, based upon block copolymer weight, of blocks derived from propylene oxide. The amounts of the components are based upon total composition weight and when taken together total 100 wt. percent. The compositions have a first viscosity in the absence of water and a second viscosity in the presence at least 10 wt. percent water based upon combined weight of composition and water. The second viscosity has a value that is at least 60 percent of the value of the first viscosity, wherein the first and second viscosities are determined according to American Society for Testing and Materials (ASTM) D-445 at 40 degrees centigrade (⁰C). Such compositions may be used in a method of lubricating a surface and methods of reducing sheen on the surface of water due to leakage of lubricant from a marine vessel. Thus, the methods described herein include a) selecting a composition comprising the appropriate amounts of the one or more random alkylene oxide interpolymers and the one or more alkylene oxide block interpolymers; and b) providing the composition to the surface. Some methods are particularly suitable for lubricating stern tube bearings of a marine vessel or fin stabilizer bearings of a marine vessel.

[0007] In particular embodiments, the compositions having desirable viscosity characteristics include a) from 40 wt. percent to 60 wt. percent of one or more random alkylene oxide interpolymers, comprising from 50 wt. percent to 55 wt. percent of polymer units derived from ethylene oxide; and b) from 40 wt. percent to 60 wt. percent of one or more alkylene oxide block interpolymers having from 40 wt. percent to 90 wt. percent of polymer units derived from propylene oxide; wherein the compositions have a first viscosity in the absence of water and a second viscosity in the presence of at least 10 wt. percent of water based upon combined weight of composition and water. Amounts of a) and b), when taken together, total 100 wt. percent. The second viscosity has a value that is at least 60 percent of the value of the first viscosity, wherein the first and second viscosities are determined according to ASTM D445 at 4O⁰C. Preferably, some compositions include two random alkylene oxide interpolymers.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0008] In the following description, all numbers disclosed herein are approximate values, regardless of whether the word "about" or "approximate" is used in connection therewith or not. They may vary by 1%, 2%, 5%, and sometimes, 10 to 20%. Whenever a numerical range with a lower limit, R^L and an upper limit, R^u, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R^L+k*(R^u-R^L), wherein k is a variable ranging from 1% to 100% with a 1% increment, i.e., k is 1%, 2%, 3%, 4%, 5%,..., 50%, 51%, 52%,...,

95%, 96%, 97%, 98%, 99%, or 100%. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. All ranges disclosed herein shall be interpreted as including the lower limits, R^L, and the upper limits, R^u.

[0009] Polymers described herein are sometimes referred to by their weight average molecular weight, or M_w. M_w may be determined from Gel Permeation Chromatography (GPC) data according to the following formula: ;

where W₁ is the weight fraction of the molecules with molecular weight M₁ eluting from the GPC column in fraction i and j=l. Details related to the determination of polymer molecular weights are discussed in Williams and Ward in the Journal of Polymer Science, Polymer Letters, Vol. 6, (621) 1968.

[0010] Embodiments of the invention provide a polymer composition wherein one or more random alkylene oxide interpolymers are combined with one or more alkylene oxide block interpolymers to provide a composition comprising 15 wt. percent to 60 wt. percent of the random alkylene oxide interpolymer and 40 wt. percent to 85 wt. percent of the block alkylene oxide interpolymer. Unless otherwise indicated all amounts herein are based on the weight of the recited components as described below. Consequently, components that are not recited may be present in some embodiments, but those components are not considered in determining the relative amounts of the recited components.

[0011] Alkylene oxide block interpolymers useful in the embodiments of the invention include blocks or segments derived from at least two monomers of formula I

R R

Formula I: p_{j P} Q p_j

\ /

O

in which each R, independently, is hydrogen, a C]-C₆ (one to six carbon atoms) alkyl or haloalkyl radical, or in which the two R substituents together with both vicinal epoxy carbons form a saturated or monoethylenically unsaturated cycloaliphatic hydrocarbon ring, preferably of five or six carbon atoms. Some alkylene oxide monomers contain 2 to 12 carbon atoms (C₂-C₁₂), and representative alkylene oxide monomers include ethylene oxide, propylene oxide, the butylene oxides, 1 ,2-epoxydodecane, cyclopentene oxide, cyclohexene oxide, and styrene oxide. Polymers having blocks derived from ethylene oxide monomers and blocks derived from propylene oxide monomers represent preferred alkylene oxide block interpolymers herein. Such block interpolymers are generally prepared by the sequential polymerization of monomer types as is known in the art. In some embodiments, alkylene oxide block interpolymers are made using a propylene glycol (1,2-propane diol), also referred to as monopropylene glycol, initiator wherein a propylene mid-oxide block is first formed followed by terminal ethylene oxide blocks. Alternatively, dipropylene glycol may be used as an initiator.

[0012] Alternatively, block interpolymers can be described as including at least one block of a first alkylene oxide and at least one block of a second alkylene oxide. This includes, for example, a single ethylene oxide block and a single propylene oxide block. Block copolymers may also include those that have two blocks of a first alkylene oxide sandwiching a single block of a second alkylene oxide as in (EO)_a(PO)b(EO)_c or (PO)_Ci(EO)₆(PO)^ where the variables a through f denote the number of repeat units of the individual alkylene oxide blocks in the interpolymer. Of course, block interpolymers having blocks formed from at least one additional alkylene oxide as well as alternating block copolymers with four or more alkylene oxide units are envisioned. Thus, alkylene oxide block interpolymers useful herein include block polymers having any number of blocks in any desirable configuration. Preferred block interpolymers have three blocks (also known as triblock polymers), with a central block of one alkylene oxide and terminal blocks of another alkylene oxide.

[0013] Both conventional block interpolymers and so-called "reverse block" polymers may be useful. Typically, the terms "block" and "reverse block" refer to the arrangement of the polymer blocks within the polymer molecules. For illustrative purposes only, an ethylene oxide-propylene oxide system demonstrates these two classes of polymers. Where block interpolymers having more than two blocks are considered, conventional block ethylene oxide/propylene oxide polymers comprise terminal ethylene oxide blocks and an intermediate block derived from propylene oxide. Such a polymer is sometimes referred to as an EO/PO/EO block polymer. Reverse block ethylene oxide/propylene oxide copolymers comprise terminal blocks derived from propylene oxide and an intermediate block derived from ethylene oxide and are sometimes referred to as PO/EO/PO block polymers. Nevertheless, the terms block and reverse block should not be construed to be limited to ethylene oxide/propylene oxide systems or be limited to polymers having only ethylene oxide and propylene oxide blocks. For instance a block interpolymer having units derived from ethylene oxide, propylene oxide, and butylene oxide would be considered a conventional block interpolymer if the terminal blocks comprise ethylene oxide, designated EO/PO/BO/EO. Conversely, a block polymer in such a system would be a "reverse block" interpolymer if the units derived from ethylene oxide are not the terminal blocks. Such a reverse block interpolymer may have a block structure such as PO/EO/BO/PO or BO/EO/PO/BO, or BO/EO/BO/PO. Typically, conventional triblock ethylene oxide/propylene oxide block interpolymers are preferred. Block copolymers are described in Non-Ionic Surfactants & Polyoxyalkylene Block Copolymers, Surfactant Science Series, Vol. 60 (Vaugh M. Nace, ed, Marcel Dekker Inc.), incorporated herein by reference in its entirety.

[0014] With respect to the block structure, the designation of a block polymer as either a conventional block copolymer or reverse block copolymer coupled with the one or more comonomer content value, and the overall molecular weight defines the size and type of blocks that may be present. While blocks of units derived from a particular monomer are generally of substantially the same size, this need not be the case. For example, while a conventional block or "reverse block" interpolymer typically has terminal blocks of substantially the same number of polymer units, asymmetric block polymers or those having terminal blocks that have substantially different number of polymer units with respect to each other may be useful.

[0015] The alkylene oxide block interpolymers present in compositions of the present invention can comprise from 40 wt. percent to 85 wt. percent of such compositions, based upon total composition weight. In particular compositions, the lower limit on the alkylene oxide block interpolymer in the composition is 45 wt. percent, 50 wt. percent, 55 wt. percent, 60 wt. percent, 65 wt. percent, 70 wt. percent, or 75 wt. percent. The upper limit of the range of alkylene oxide block interpolymer in some embodiments is 50 wt. percent, 55 wt. percent, 60 wt. percent, 65 wt. percent, 70 wt. percent, 75 wt. percent, or 80 wt. percent. Some useful compositions include from 50 wt. percent to 75 wt. percent. Other useful compositions include from 40 wt. percent to 60 wt. percent based upon total composition weight. In still other compositions, the alkylene oxide block interpolymer comprises from 50 wt. percent to 55 wt. percent of the composition. The relative amounts of the block alkylene oxide interpolymer in the composition are determined with respect to the amounts of each of the random alkylene oxide interpolymers and each of the block alkylene oxide interpolymers present in the composition according to the equation:

∑^Wblock,ι

L " random,ι ' 2J " block, i

wherein W_bi_ock i represents the weight of each block alkylene oxide interpolymer present in the composition and W_randOmi represents the weight of each random alkylene oxide interpolymer present in the composition.

[0016] Alkylene oxide block interpolymers used in embodiments of the invention preferably have a M_w ranging from 1500 g/mol to 4000 g/mol. In some embodiments, the alkylene oxide block interpolymers have a M_w of from 1500 g/mol to 3000 g/mol, preferably from 1750 g/mol to 2250 g/mol, more preferably from 1850 g/mol to 2150 g/mol, and still more preferably from 1900 g/mol to 2100 g/mol.

[0017] Suitable alkylene oxide block interpolymers typically have 40 wt. percent to 90 wt. percent of polymer units derived from propylene oxide. Some preferred alkylene oxide block interpolymers have from 85 wt. percent to 90 wt. percent of polymer units derived from propylene oxide. In particular compositions, the alkylene oxide block interpolymer comprises from 65 wt. percent to less than 85 wt. percent of polymer units derived from propylene oxide. In some compositions, the block alkylene oxide interpolymer is an ethylene oxide/propylene oxide polymer, particularly those with less than 50 wt. percent of polymer units derived from ethylene oxide, more particularly those with from 10 wt. percent to less than 50 wt. percent of polymer units derived from ethylene oxide, and still more particularly those with from 10 wt. percent to less than 35 wt. percent of polymer units derived from ethylene oxide. Thus, in some embodiments, the alkylene oxide block interpolymer includes polymer units derived from ethylene oxide and propylene oxide wherein from greater than 70 wt. percent to 90 wt. percent, preferably greater than 80 wt. percent or 85 wt. percent to 90 wt. percent, of the polymer units are derived from propylene oxide. Some such polymers are commercially available from The Dow Chemical Company under the Dowfax^™ and Tergitol™ brands.

[0018] The random alkylene oxide interpolymer preferably have polymerized therein at least the same alkylene oxide monomers as are present in the block copolymers. In contrast to block interpolymers, random polymers are generally prepared from a reaction mixture having present therein each of the constituent monomers in their desired amounts during the polymerization. Consequently, the structures of the individual polymer molecules have a random distribution of units derived from each of the monomers present during the process. Random alkylene oxide interpolymers having units derived from any number of different monomers of Formula I may be used. Typically, the random alkylene oxide interpolymer have units derived from two or three such monomers, with ethylene oxide, propylene oxide, and butylene oxide monomers being preferred. In some embodiments, random ethylene oxide/propylene oxide polymers are used. Random copolymers are described in detail in Synthetic Lubricants & High Performance Functional Fluids, Leslie Rudnick and Ronald Shubkin, eds., 2^nd ed., incorporated herein by reference in its entirety.

[0019] The random alkylene oxide interpolymers can comprise from 15 wt. percent to 60 wt. percent of the composition, but preferably comprise from 40 wt. percent to 60 wt. percent, more preferably 50 wt. percent to 55 wt. percent, of the composition. Determine relative amounts of the interpolymer components based only on the amounts of the random alkylene oxide interpolymer and alkylene oxide block interpolymer present in a composition. In other words, the weight percent of the random alkylene oxide interpolymer component can be determined by the following equation:

2J " random,ι

L " random,ι ' 2J " block, i

wherein W_rando_m i and Wbioc_k i are as defined above. Particular embodiments include one or more random alkylene oxide interpolymers with a M_w ranging from 250 g/mol to 2000 g/mol, particularly from 250 g/mol to 1200 g/mol, preferably from 250 g/mol to 1000 g/mol. Typically, the random alkylene oxide interpolymer has from 30 wt. percent to 60 wt. percent of polymer units derived from ethylene oxide. In particular embodiments, the random alkylene oxide interpolymer has from 40 wt. percent to 60 wt. percent, preferably from 50 wt. percent to 55 wt. percent polymer units derived from ethylene oxide. In some compositions, two or more, preferably only two, of such random alkylene oxide interpolymers are used.

[0020] In particular embodiments, the compositions comprise from 40 wt. percent to 60 wt. percent of one or more random ethylene oxide/propylene oxide interpolymers having a M_w ranging from 250 g/mol to 1200 g/mol and having from 40 wt. percent to 60 wt. percent of the polymer units derived from ethylene oxide and one or more block ethylene oxide/propylene oxide interpolymers having a M_w ranging from 1750 g/mol to 2500 g/mol and having from 40 wt. percent to 90 wt. percent of the polymer units derived from propylene oxide. Some such polymers are commercially available from The Dow Chemical

Company under the UCON^® and Synalox^™ brands.

[0021] The random and block interpolymers described herein can be combined by any convenient method. Generally, the M_w's of the components are low enough that the compositions can be prepared by any suitable method for mixing liquids. For industrial scale preparation, the amounts of desired random and block interpolymer components can be provided to a stainless steel mixing vessel and stirred at a temperature typically between ambient temperature (nominally 25⁰C) and 6O⁰C. Blending may be accomplished in one or more steps. In addition, additives may be blended with the composition in any desirable manner, such as being blended contemporaneously with one or more interpolymer components or they may be provided in smaller portions or aliquots at intermediate stages of the blending process.

[0022] Some compositions are characterized by desirable viscosity behavior in the presence of relatively large amounts of water. Thus, some compositions have a first viscosity in the substantial absence of water and an acceptable second viscosity when combined with water. Typically, the first viscosity ranges from 50 centistokes (cSt) (5 x 10^" ⁵ square meters per second (m²/sec)) to 150 cSt (15 x 10^"5 m²/sec), preferably from 50 cSt (5 x 10^"5 m²/sec) to 120 cSt (12 x 10^"5 m²/sec), and more preferably from 70 cSt (7 x 10^"5 m²/sec) to 110 cSt (H x 10^"5 m²/sec). In some embodiments, the second viscosity, as determined when the amount of water present ranges from 10 wt. percent to 50 wt. percent, based upon composition weight, has a value that is at least 60 percent of the value of the first viscosity. For example, some compositions have a first viscosity in the absence of water, and then in the presence of 20 wt. percent water, the mixture of the polymer composition and water has second viscosity that is at least 60 percent of the value of the viscosity when water is absent. In other compositions, the second viscosity is at least 60 percent of the value of the first viscosity when the composition includes 30 wt. percent water, 40 wt. percent water or even 50 wt. percent water. Some compositions are characterized by a value of the second viscosity that is at least 80 percent of the value of the first viscosity when the composition includes 40 wt. percent water. In other compositions, the second viscosity has a value that is at least 90 percent of the first viscosity when composition includes 40 wt. percent water.

[0023] While the viscosity of the mixtures of the block and random alkylene oxide interpolymer components generally decreases when water is present, some compositions show an increase in viscosity in the presence of relatively small amounts of water. Thus, some preferred compositions have a second viscosity that is up to 11 percent greater than the first viscosity when the amount of water present is 5 wt. percent.

[0024] Particular polymer compositions having one or more of the improved viscosity properties described above comprise from 40 wt. percent to 60 wt. percent, based upon composition weight, of at least one random alkylene oxide interpolymer, each random interpolymer comprising from 50 wt. percent to 55 wt. percent of polymer units derived from ethylene oxide; and from 40 wt. percent to 60 wt. percent, based upon composition weight, of at least one alkylene oxide block interpolymer. Particularly useful compositions are prepared by providing two random ethylene oxide/propylene oxide interpolymers that are present in an amount totaling from 40 wt. percent to 60 wt. percent.

[0025] Some polymer compositions described herein can be used for lubricating surfaces. Thus, in some embodiments the invention relates to methods of lubricating a surface that include selecting a composition described herein; and providing the composition to the surface. The lubricants are particularly suitable for use in lubricating bearings in a marine vessel, particularly stern tube bearings and fin stabilizer bearings. While the compositions may be used to lubricate any bearing on a marine vessel, lignum vitae bearings, metal bearings and Cedervall type bearings are most common.

[0026] Some polymer compositions described herein form substantially less sheen on the surface of water than formulated conventional lubricant compositions. Thus, in some embodiments, compositions described herein can be used to reduce sheen on the surface of water due to leakage of lubricant from a marine vessel. Typically, reduced sheen can be detected by visual comparison of the appearance of the sheen formed on the surface of the water.

EXAMPLES

[0027] The following examples recorded in Tables 1-13 below are prepared by combining one or more of the following components. Polymers A, C, F, G, K, L and T include no viscosity profile data.

[0028] Polymer A is a triblock ethylene oxide/propylene oxide (EO/PO) interpolymer having a M_w of 3910 g/mol and a propylene oxide content of 85 wt. percent, based upon copolymer weight.

[0029] Polymer B is a triblock EO/PO interpolymer having a M_w of 2800 g/mol and a propylene oxide content of 85 wt. percent based upon copolymer weight. Polymer B has the following viscosity profile.

0 wt. % 10 wt. % 20 wt. % 30 wt. % 40 wt. % 50 wt. % water water water water water water

Viscosity (cST)/

254.5/ 365.9/

(x 10 m /sec) 25.4 36.6

"— " denotes that the viscosity was not determined. [0030] Polymer C is a butanol-initiated random EO/PO interpolymer in which the ethylene oxide content is 50 wt. percent, based upon copolymer weight, with a M_w of 270 g/mol.

[0031] Synthesis of butanol-initiated random EO/PO interpolymers (Polymers C and D), diol-initiated random EO/PO interpolymers (Polymers E and I), monopropylene glycol- initiated EO/PO triblock interpolymers (Polymers M, N, O, P and Q), trimethylolpropane- initiated EO/PO diblock copolymers (Polymer R), and glycerol-initiated EO/PO reverse diblock copolymers (Polymers S and T) involves a chemical reaction of EO and PO with an initiator that contains a reactive hydrogen atom, e.g. butanol for Polymers C and D.

[0032] Polymer D is a butanol-initiated random EO/PO interpolymer with an ethylene oxide content of 50 wt. percent, based upon copolymer weight, and a M_w of 970 g/mol. Polymer D has the following viscosity profile.

0 wt. % 10 wt. % 20 wt. °k 30 wt. °k 40 wt. % 50 wt. °k water water water water water water

Viscosity

(cST) )/ 52.2/ 53.4/ 43.7/ 32.9/ 29.5/ 18.8/ 5.22 5.34 4.37 3.29 2.95 1.88

(x 10^"5m²/sec)

[0033] Polymer E is a diol-initiated random EO/PO interpolymer with a M_w of about 1600 g/mol and an ethylene oxide content of 45 wt. percent, based upon copolymer weight. Polymer E has the following viscosity profile.

0 wt. % 10 wt. % 20 wt. °k 30 wt. % 40 wt. % 50 wt. % water water water water water water

Viscosity

(cST) )/ 96.1/ 100.3/ 84.5/ 66/ 46/ 28/ 9.61 10.03 8.45 6.6 4.6

((x 10^"5m²/sec))

[0034] Polymer F is a triblock EO/PO interpolymer having a M_w of 2500 g/mol and a propylene oxide content of 70 wt. percent, based upon copolymer weight.

[0035] Polymer G is a triblock EO/PO interpolymer having a M_w of 2750 g/mol and a propylene oxide content of 85 wt. percent, based upon copolymer weight. [0036] Polymer H is a triblock EO/PO interpolymer having a M_w of 2600 g/mol and a propylene oxide content of 87 wt. percent, based upon copolymer weight. Polymer H has the following viscosity profile.

Viscosity (cST)/

226.5/ 334.2/ (x 10^"5m²/sec) 22.65 33.42 denotes that the viscosity was not determined.

[0037] Polymer I is a diol-initiated random EO/PO copolymer in which the ethylene oxide content is 60 wt. percent, based upon copolymer weight, with a M_w of lOOOg/mol. Polymer I has the following viscosity profile.

Viscosity (cST)/ 72.9/ 68.3/ 53.9/ 34.2/ 19.5/ 15.9/ (x 10^"5m²/sec) 7.29 6.83 5.39 3.42 1.95 1.59

[0038] Polymer J is a triblock EO/PO interpolymer having a M_w of 2300g/mol and a propylene oxide content of 70 wt. percent, based upon copolymer weight. Polymer J has the following viscosity profile.

Viscosity (cST)/

197.2/ 269.8/ 313.1/ 671.0/ 141.6/ (x 10^"5m²/sec) 19.72 26.98 31.31 67.1 14.16 denotes not determined.

[0039] Polymer K is a polyol ester lubricant, available from Hatco as HATCOL 5068. It has a viscosity at 4O⁰C of 68 cSt, (6.8 x 10^"5 m²/sec), a viscosity at 100⁰C of 9 cSt

(0.9 x 10^"5 m²/sec); a pour point of -37⁰C, an open cup flash point of 237⁰C. Because

Polymer K forms an immiscible mixture when water is present between 1 wt and 50 wt percent, the viscosity in the presence of water is not determined.

[0040] Polymer L is a rapeseed oil-based lubricant having a viscosity at 4O⁰C of 31 cSt (3.1 x 10^"5 m²/sec), a viscosity at 100⁰C of 9 cSt (0.9 x 10^~5m²/sec); and a density at 15⁰C of 930 Kg/m³ and flash point in excess of (>) 22O⁰C. This fluid has an initial viscosity of 28 cSt (2.8 x 10^" m²/sec) at 4O⁰C. Because Polymer L forms an immiscible mixture when water is present between 10 wt. percent and 50 wt. percent, the viscosity in the presence of water is not determined.

[0041] Polymer M is a monopropylene glycol-initiated EO/PO triblock interpolymer

(sometimes referred to as an EO/PO triblock copolymer) having a M_w of 2400 g/mol and a propylene oxide content of 60 wt. percent, based upon copolymer weight. Polymer M has the following viscosity profile.

Viscosity (cSt)/

248.7/ 301.3/

(x 10 m /sec) 24.87 30.13 denotes not determined.

[0042] Polymer N is a monopropylene glycol-initiated EO/PO triblock copolymer having a M_w of 1900 g/mol and an ethylene oxide content of 90 wt. percent, based upon copolymer weight. Polymer N has the following viscosity profile.

Viscosity (cSt)/

152/ 169.3/

(x 10 m /sec) 15.2 16.93 denotes not determined.

[0043] Polymer O is a monopropylene glycol-initiated EO/PO triblock copolymer having a M_w of 2000 g/mol and a propylene oxide content of 85 wt. percent, based upon copolymer weight. Polymer O has the following viscosity profile.

Viscosity (cSt)/

154.9/ 195.2/ 276.9/ 362.5/

(x 10 m /sec) 15.49 19.52 27.69 36.25 denotes not determined.

[0044] Polymer P is a monopropylene glycol-initiated EO/PO triblock copolymer having a M_w of 2700 g/mol and an propylene oxide content of 90 wt. percent, based upon copolymer weight. Polymer P has the following viscosity profile. 0 wt. % 10 wt. % 20 wt. % 30 wt. % 40 wt. % 50 wt. % water water water water water water

Viscosity (cStT)/

220.3/ 396.1/ 629.3/

(x 10^"5m²/sec) 22.03 39.61 62.93

"—"denotes not determined.

[0045] Polymer Q is a monopropylene glycol-initiated EO/PO triblock copolymer having a M_w of 3800 g/mol and a propylene oxide content of 84 wt. percent, based upon copolymer weight. Polymer Q has the following viscosity profile.

0 wt. % 10 wt. % 20 wt. % 30 wt. % 40 wt. °k 50 wt. °k water water water water water water

Viscosity (cSt)/

310.2/ 1358.7/ (x 10^"5m²/sec) 31.02 135.87

^: "—"denotes not determined.

[0046] Polymer R is a trimethylolpropane-initiated EO/PO diblock copolymer having a M_w of 4500 g/mol and a propylene oxide content of 10 wt. percent, based upon copolymer weight. Polymer R has the following viscosity profile.

Viscosity (cSt)/

351.4/ (x 10^"5m²/sec) 35.14

"—"denotes not determined

[0047] Polymer S is a glycerol-initiated EO/PO reverse diblock copolymer having a

M_w of 4500 g/mol and a propylene oxide content of 87 wt. percent, based upon copolymer weight. Polymer S has the following viscosity profile.

Viscosity (cSt)/

293.9/ 309.5/ (x 10^"5m²/sec) 29.39 30.95

"—"denotes not determined

[0048] Polymer T is a glycerol-initiated EO/PO reverse diblock copolymer having a M_w of 3500 g/mol and a propylene oxide content of 65 wt. percent, based upon copolymer weight. [0049] The initial viscosity of the compositions is determined according to ASTM D-445 at 4O⁰C. To determine the effect of water on the viscosity, a sample of each composition is combined with an amount of water sufficient to yield a diluted composition with a water content ranging from 10 wt. percent to 50 wt. percent, based upon diluted composition weight. For those samples that form a miscible mixture, the viscosity of the mixture is measured according to the same method. Generally, miscible mixtures have a clear appearance. An immiscible mixture is generally indicated by a cloudy mixture, or in extreme cases by separation of the phases. The viscosity of immiscible mixtures is not determined.

[0050] The following data are reported to demonstrate the viscosity characteristics and physical properties of various blends made from the above-described polymers. While some of the following examples fall within the compositional ranges of the invention, they may have viscosity profiles that are undesirable. Nevertheless, such examples should in no way be considered to limit the scope of protection afforded to compositions that otherwise fall within the claims but may not have been reported herein.

Table 1

'—"denotes not determined.

Table 1 (cont'd)

[0051] Examples of Table 2 are formulated compositions including conventional additive packages along with the block polymer and random polymer components. Typical additive packages include antioxidants and corrosion inhibitors such as a combination of (4- nonlyphenol) acetic acid, a proprietary acylsarkosinate and nonyl phenol (Irgacor^® L17), N- phenyl-ar-(l,l,3,3-tetramethylbutyl)-l-naphthaleneamine Irganox^® L06, a reaction product of N-phenylbenzenamine with 2,4,4-trimethylpentent diphenylamine (Irganox^® L57), tolyltriazole and monomethyl hydroquinone. Irganox^® is a trademark of the Ciba Geigy Corporation. Additives may be used in any convenient combination or amount but typically comprise from 0.5 wt. percent to 5 wt. percent, preferably from 1 wt. percent to 3 wt. percent, of the total composition. One preferred additive package comprises 0.9 wt. percent Irgacor^® L17, 0.25 wt. percent Irganox^® L06, 0.25 wt. percent Irganox^® L57, 0.1 wt. percent tolyltriazole and 0.5 wt. percent monomethyl hydroquinone, each wt. percent being based upon total composition weight.

Table 2

* Examples 11-13 include 0.9 wt. percent Irgacor" Ll 7, 0.25 wt. percent Irganox ^R L06, 0.25 wt. percent Irganox^® L57, 0.1 wt. percent tolyltriazole and 0.5 wt. percent monomethyl hydroquinone, each wt. percent being based upon total composition weight. Table 3

"—"denotes not determined. "*" denotes a comparative composition, not part of the invention. Table 4

"—"denotes not determined

"*" denotes a comparative composition, not part of the invention

Table 5

"—"denotes was not determined

"*" denotes a comparative composition, not part of the invention

Table 6

"—"denotes not determined

"*" denotes a comparative composition, not part of the invention. Table 7

"—"denotes not determined

"*" denotes a comparative composition, not part of the invention. Table 8

"—"denotes not determined

"*" denotes a comparative composition, not part of the invention Table 9

"—"denotes not determined ^!" denotes a comparative composition, not part of the invention Table 10

"—"denotes not determined

"*" denotes a comparative composition, not part of the invention

Table 11

"—"denotes not determined

Table 12

[0052] Prepare a representative blend of Polymer J and Polymer D. The composition includes 18.6 wt. percent of Polymer D, 80 wt. percent of Polymer J and 1.4 wt. percent of an additive package comprising 0.9 wt. percent Irgacor^® L17, 0.25 wt. percent

Irgacor L06, and 0.25 wt. percent a reaction product of N-phenylbenzenamine with 2,4,4- trimethyl pentene and 2-methylpropene (Vanlube™ 961), each wt. percent being based upon total composition weight. Irgacor is a trademark of the Ciba Geigy Corporation. Vanlube is a trademark of the R.T. Vanderbilt Company, Inc. The viscosity of this formulated blend is determined in deionized water and in synthetic seawater (prepared according to ASTM D665). The composition performs well in deionized water up to a water content of 40 wt. percent, based upon combined weight of composition and deionized water. The viscosity in synthetic seawater increases when sea water is present and remains acceptable at water concentrations of 50 wt. percent, based upon combined weight of composition and synthetic seawater. These results are summarized in Table 13.

Table 13

[0053] These examples show that compositions of random and block copolymers can be utilized to provide good rheology control when aqueous dilutions of the compositions are formed. Rheology control depends on several factors such as the molecular weight (M_w) and ethylene oxide content of the random copolymer and also the molecular weight (M_w) and propylene oxide content of the block copolymer. Furthermore, the weight ratios of random and block copolymers can be used to optimize and control rheology performance in aqueous solution. Block copolymers which contain at least 70 wt. percent propylene oxide content and M_w's of from 1500 to 4000 g/mol are preferred. Random copolymers containing 50 wt. percent ethylene oxide units and having M_w's of less than 2000 g/mol, particularly from 500 to 1200 g/mol, are also preferred. [0054] Compositions which contain only random copolymers of ethylene oxide and propylene oxide, for example Polymers E (Comparative Example 4) or I (Comparative Examples 3 and 13), show poor rheology control and significant viscosity decrease when 50 wt. percent water is present in the composition. Furthermore, compositions which contain only block copolymers, also show poor rheology control and a significant increase in viscosity on water addition such that gel formation occurs. This is exemplified with Polymer Q in Table 4 which forms a gel at 50 wt. percent aqueous dilution.

[0055] Compositions of random copolymers and block copolymers can provide the desired rheology control. Some compositions which contain 50 wt. percent random copolymer and 50 wt. percent block copolymer show excellent rheology control. For example, a composition which contains 50 wt. percent Polymer Q and 50 wt. percent Polymer D in Table 4 shows less than 6 percent viscosity change with 50 wt. percent water addition. Similarly Example 2 in Table 1 , which describes a composition containing block copolymer B at 50 wt. percent with random copolymers C and D at 10 wt. percent and 40 wt. percent, respectively, shows less than 13 percent viscosity change when combined with 50 wt. percent water.

[0056] The ethylene oxide content of the random copolymer is important when considering the stability of compositions that contain block copolymers in the presence of water. When the level of ethylene oxide in the random component is too high, aqueous compositions are often hazy, cloudy or milky in appearance. When the ethylene oxide content of the random copolymer is from 50 wt. percent to 55 wt. percent, compositions that contain block copolymers can lead to clear stable aqueous solutions, as illustrated by Polymers Q and D (Ex 15) in Table 4.

[0057] While the invention has been described with a limited number of embodiments, these specific embodiments are not intended to limit the scope of the invention as otherwise described and claimed herein. Modification and variations from the described embodiments exist. For instance, embodiments of the compositions described herein may, rather than comprise, consist of or consist essentially of the enumerated components. Other embodiments are substantially free of or essentially free of any component not expressly recited. Some compositions are substantially free of water while some compositions are substantially free of alcohol alkoxylates. Some compositions comprise less than 0.5 wt. percent of one or more alcohol alkoxylates. In some embodiments, the compositions may be substantially free of both water and alcohol alkoxylates. While the processes are described as comprising one or more steps, it should be understood that these steps may be practiced in any order or sequence unless otherwise indicated. These steps may be combined or separated.

[0058] Finally, any number disclosed herein should be construed to mean approximate, regardless of whether the word "about" or "approximate" is used in describing the number. Last but not the least, the claimed compositions are not limited to preparation by the processes described herein. They can be prepared by any suitable process. The appended claims intend to cover all such variations and modifications as falling within the scope of the invention.

Claims

[0059] What is claimed is:

1. A polymer composition, comprising:

a) from 15 weight percent to 60 weight percent, based upon composition weight, of one or more random alkylene oxide interpolymers, each of which has a weight average molecular weight ranging from 250 g/mol to 2000 g/mol and comprises from 30 weight percent to 60 weight percent, based upon random interpolymer weight, of polymer units derived from ethylene oxide; and

b) from 40 weight percent to 85 weight percent, based upon composition weight, of one or more alkylene oxide block interpolymers, each of which has a weight average molecular weight ranging from 1500 g/mol to 4000 g/mol and comprises from 40 weight percent to 90 weight percent, based upon block copolymer weight, of blocks derived from propylene oxide;

wherein the composition has a first viscosity in the substantial absence of water and a second viscosity in the presence of an amount of water, and

wherein the second viscosity, when the amount of water present is at least 10 weight percent based upon combined weight of composition and water, has a value that is at least 60 percent of the value of the first viscosity, wherein the first and second viscosities are determined according to ASTM D-445 at 4O⁰C.

2. The polymer composition according to claim 1, wherein each random alkylene oxide interpolymer has a weight average molecular weight ranging from 250 g/mol to 1200 g/mol.

3. The polymer composition according to claim 1, wherein the one or more random alkylene oxide interpolymers comprise from 40 weight percent to 60 weight percent of the composition.

4. The polymer composition according to claim 3, wherein the one or more random alkylene oxide interpolymers comprise 50 weight percent to 55 weight percent of the composition.

5. The polymer composition according to claim 1, wherein the one or more alkylene oxide block interpolymers comprises from 50 weight percent to 75 weight percent of the composition.

6. The polymer composition according to claim 1, wherein the one or more alkylene oxide block interpolymers comprise 40 weight percent to 60 weight percent of the composition.

7. The polymer composition according to claim 1, wherein each of the one or more alkylene oxide block interpolymers comprises from 10 weight percent to less than 50 weight percent, based upon block copolymer weight, of polymer units derived from ethylene oxide.

8. The polymer composition according to claim 1, wherein each of the one or more alkylene oxide block interpolymers has a weight average molecular weight ranging from 1750 g/mol to 2500 g/mol.

9. The polymer composition according to claim 1, wherein each random alkylene oxide interpolymer has a weight average molecular weight ranging from 250 g/mol to 1200 g/mol and comprises polymer units derived from ethylene oxide and propylene oxide with from 30 weight percent to 60 weight percent of the polymer units, based upon total weight of polymer units, being derived from ethylene oxide; and

wherein each alkylene oxide block interpolymer has a weight average molecular weight ranging from 1750 g/mol to 2500 g/mol and comprises polymer units derived from ethylene oxide and propylene oxide with from 60 weight percent to 90 weight percent of the polymer units, based upon total weight of polymer units, being derived from propylene oxide.

10. The composition of claim 1, wherein the first viscosity ranges from 50 centistokes (5 x 10^"5 m²/sec) to 120 centistokes (12 x 10^"5 m²/sec).

11. The composition of claim 1, wherein the second viscosity ranges from 0 percent greater to less than 11 percent greater than the first viscosity when the amount of water present is 5 weight percent.

12. The composition of claim 1, wherein the composition comprises less than 0.5 weight percent of one or more alcohol alkoxylates.

13. A method of lubricating a surface, which method comprises providing the polymer composition of any of claims 1 through 12 to the surface.

14. The method of claim 13, wherein the surface is selected from a stern tube bearing of a marine vessel or a fin stabilizer bearing of a marine vessel.