BRPI0707767A2 - base raw material or base oil, functional fluid composition, and method of producing a functional fluid - Google Patents

Abstract

RAW MATERIAL BASE OR BASE OIL, FUNCTIONAL FLUID COMPOSITION, AND, PRODUCTION METHOD OF A FUNCTIONAL FLUID A base oil having an unexpectedly low dynamic viscosity measured by the ASTM D5 133 test method is composed of a mixture of about 65 to 97.5 % of a paraffinic oil having a VI of 130 or greater, a Kv @ 1000C around 3.8 cSt or greater and a pour point of -1 5 <198> C or less and an ester with a lubricating viscosity of about 35 to about 2.5% by weight. The base oil is additionally characterized as free from added viscosity modifiers.

Description

"BASE OR OIL BASED RAW MATERIAL, FLUID FUNCTIONAL COMPOSITION, AND METHOD OF PRODUCTION OF A FUNCTIONAL FLUID"

Field of the invention

This invention relates to base oil mixtures for functional fluids, especially hydraulic fluids, which have an unexpectedly low dynamic viscosity. This invention also relates to a lubricating composition or functional fluids composed of these base oil mixtures.

Fundamentals of the invention

Hydraulic equipment owners require their equipment to operate effectively over a wide range of temperatures. For example, cargo loading systems on board cargo ships should be able to operate independently of the prevailing climate that may vary from tropical to arctic conditions. As a result, hydraulic oils have been developed that have good low temperature flow properties for service under cold weather conditions and that can perform well under hot weather conditions.

To achieve the desired wide working temperature ranges, hydraulic fluids are commonly formulated in two ways. The first form involves the use of mixtures of solvent refined baseparaffin oils and solvent refined naphthenic base oils with an added viscosity modifier and a low pour point. The second form involves the use of an alpha olefin oil base oil (PAO, group IV base raw material).

The first method requires a more complete formulation strategy, but is generally preferred because it is more cost effective than the second form, which requires a special expensive PAO base material. However, the viscosity index modifiers used in the first technique are subject to traction in service, thus causing a performance degradation.

A base feedstock (as opposed to a base oil and a functional fluid) is defined as a single manufacturer hydrocarbon stream to the same specification (regardless of the feed source) and is characterized by a unique formula, product identification number , or both. The base raw materials may be manufactured using a variety of different processes including, but not limited to distillation, solvent refining, hydrogen processing, oligomerization, esterification, and refining. Refining raw material must be substantially free of materials introduced during manufacture, contamination or prior use. A base oil is the base material or mixture of base materials used in formulated lubricants or functional fluid compositions. A lubricating composition may be a base raw material, a base oil, alone or mixed with other functional raw materials, oils or additives.

An object of the present invention is to provide functional fluids, and especially hydraulic fluids which perform well under temperature and in the absence of an added viscosity modifier.

Another object of the present invention is to provide functional fluids, and especially hydraulic fluids, which utilize a different oil based on PAO.

These and other objectives will become apparent from the following description.

Summary of the invention

Broadly presented, the present invention includes base raw materials, base oils and functional fluid compositions that have surprising and unexpected accumulation of high viscosity index (VI) properties and good low temperature performance in the absence of a viscosity index modifier. .

In a preferred embodiment, base oils are presented as starting materials which are composed of:

(a) from about 65 to about 97.5% by weight, based on base stock or base oil, of an oil having a VI of 130 or greater, a Kv at 100 ° C of 3.8 cSt or greater and a pour point of -15 ° C lower; and

(b) about 2.5 to about 35% by weight, based on the base raw material or base oil, of a lubricating viscosity ester. Brief Description of the Invention

Figures 1 to 3 are graphs showing the improved dynamic viscosity of lubricant compositions of the invention as compared to polyalpha olefin based compositions as measured by ASTM D5133.

Detailed Description of the Invention

The base raw materials or base oils of the present invention both have a high viscosity index and perform well at low temperature as evidenced by their dynamic viscosity as measured by ASTM D5133. In fact, the base raw materials and base oils of the invention do not require added viscosity modifiers to achieve their low temperature performance properties.

These base raw materials are base oils and are a paraffinic oil blend having a VI of about 130 or greater, a Kv at 100 ° C of about 3.8 cSt or greater and a pour point of about -15 °. Cou minor, and a lubricating viscosity ester.

Preferably, the paraffinic oil will have a VI of from about 130 to about 160 and more preferably from about 140 to 150; a Kv at 100 ° C of about 3 cSt to about 10 cSt and more preferably about 3.8 cSt to about 6.8 cSt; and a pour point (ASTM D97) from about 0 ° C to about -30 ° C and more preferably from about -15 ° C to about -25 ° C.

Process:

The paraffinic oils cited herein are made from wax feed fillers to meet the requirements of a Group III base material, while having excellent properties such as high VI and low temperature performance.

The wax feed fillers used in these processes may be derived from natural or mineral or synthetic sources. The feed for this process may have a wax paraffin content of at least 50 wt%, preferably at least 70 wt%, and more preferably at least 80 wt%. Preferred synthetic wax feed fillers generally have a wax paraffin content by weight of at least 90 wt%, often at least 95 wt%, and in some cases at least 97 wt%. In addition, the wax-based feedstock used in these processes for the production of base materials and base oils cited herein may be composed of one or more individual, natural, mineral or synthetic wax feed fillers, or any mixture thereof.

In addition, feed loads for these processes may be obtained from conventional mineral oils, or from synthetic processes. For example, synthetic processes may include GTL (gas-in-liquid) and processes such as the Kolbei-Englehardt process and FT (Fischer-Tropsch) process in which wax hydrocarbons are catalytically produced from CO and hydrogen. Several of the preferred feed fillers are characterized as having predominantly saturated (paraffin) compositions.

In more detail, the feed loads used in the process of the invention are wax-containing feeds boiling in the range of lubricating oils, typically having a 10% distillation point greater than 650 ° F (343 ° C), measured by ASTM D86 or ASTM2887, and are derived from mineral or synthetic sources. The wax content of the feedstock is at least about 50% by weight, based on the feedstock, which may vary by up to 100% by weight of wax. The wax content of a feed may be determined by nuclear magnetic resonance spectroscopy (ASTM D5292), correlative methods (MTM D3238) or by solvent media (ASTMD3235). Wax feeds may be derived from a variety of sources, such as natural or mineral or synthetic. Specifically, wax feeds include, for example, oils derived from solvent refining processes, such as raffinates, oils partially removed from solvent evaporation, unsalted oils, distillates, vacuum gas oils, coking gas oils, greases, base oils and the like, and Fischer-Tropsch waxes. Preferred feeds are Fischer-Tropsch greases and waxes. Greases are typically derived from hydrocarbon feeds by solvent or propane wax removal. Greases contain some residual oil and are typically hate free. Base oils are derived from oil-free greases. The Fischer-Tropsch synthetic process prepares Fischer-Tropsch waxes. Nonlimiting examples of suitable decera feed fillers include Paraflint 80 (a hydrogenated Fischer-Tropsch wax) and Shell MDS wax raffinate (a partially isomerized distillate synthesis wax raffinate).

Feed loads may have high levels of nitrogen and sulfur contaminants. Feeds containing up to 0.2 wt% nitrogen based on the feed and up to 3.0 wt% sulfur can be processed in the current process. Feeds having a high wax content typically have high viscosity indexes of up to 200 or more. Sulfur and nitrogen contents can be measured using standard ASTM D5453 and D4629 methods, respectively.

For solvent extraction feeds, atmospheric distillation high boiling petroleum fractions are sent to a vacuum distillation unit, and the distillation fractions of this unit are solvent extracted. The residue from the vacuum distillation may be de-asphalted. The solvent extraction process selectively dissolves the aromatic components in an extraction phase, while also leaving the most paraffinic components in a derafinate phase. Naphthenes are distributed between the extraction and raffinate phases. Typical solvents for solvent extraction include phenol, furfural and N-methyl pyrrolidone. By controlling the solvent by the proportion of oil, extraction temperature and method of contact with the distillate to be extracted with the solvent, one can control the degree of separation between the extraction and raffinate phases.

Hydrotreatment:

For hydrotreatment, catalysts are those effective for hydrotreatment, such as Group 6 metal-containing catalysts (based on the IUPAC Periodic Table format having groups 1 through 18), metals from groups 8-10, and mixtures thereof. Preferred metals include nickel, tungsten, molybdenum, cobalt and mixtures thereof. These metals or mixtures of metals are typically present as oxides or sulfides on refractory metal oxide supports. The metal mixture may also be present as bulky metal catalysts, where the amount of metal is 30 wt.% Or greater based on the catalyst. Suitable metal oxide supports include oxides such as silica, alumina, silica alumines or titania, preferably alumina. Preferred aluminas are porous aluminas such as gamma or beta. The amount of metals, individually or in mixtures, ranges from about 0.5 to 35% by weight based on the catalyst. In the case of preferred mixtures of group 9-10 demetals with group 6 metals, group 9-10 metals are present in amounts of about 0.5 to 5% by weight based on the catalyst and group 6 metals are present. present in amounts of 5 to 30% by weight. Quantities of metals may be measured by atomic absorption spectroscopy, inductively coupled plasma atomic emission spectrometry or other methods specified by ASTM for individual metals.

The acidity of the metal oxide supports may be controlled by the addition of promoters and / or dopants, or by controlling the nature of the metal oxide support, for example by controlling the amount of silica incorporated in a silica alumina support. Examples of promoters and / or dopants include halogen, especially fluorine, phosphorus, boron, yttria, rare earth oxides and magnesia. Promoters such as halogen generally increase the acidity of metallic oxide supports, while slightly basic dopants such as yttria or magnesia tend to reduce the acidity of such supports.

Hydrotreating conditions include temperatures of 150 to 400 ° C, preferably 200 to 350 ° C, a hydrogen partial pressure of 1480 to 20,786 kPa (200 to 3000 psig), and preferably 2859 to 13891 kPa (400a 2000 psig). a spatial velocity of 0.1 to 10 net liquid space velocity (LHSV), preferably 0.1 to 5 LHSV, and a hydrogen to feed ratio of 89 to 1780 m.sup.3 / m.sup.3 ( 501 to 10,000scfTB), preferably 178 to 890 m.sup.3 / m.sup.3.

Hydrotreatment reduces the amount of contaminants containing nitrogen and sulfur to levels that will not unacceptably affect the wax removal catalyst in the subsequent wax removal step. There may also be certain polar aromatic species that will pass through the mild hydrotreating step. This contaminant, if present, will be removed in a subsequent hydro-finishing step.

During hydrotreating, less than 5 wt% of the feedstock, preferably less than 3 wt%, more preferably less than 2 wt%, is converted to products at 650 ° F (343 ° C) minus, to produce a hydrotreated feedstock whose IV increase is less than 4, preferably less than 3, more preferably less than 2, greater than the VI of the feedstock. High decera contents of current feeds result in a minimum increase of VI during the hydrotreating step.

The hydrotreated feedstock may pass directly to the wax removal step or preferably be fractionated to remove gaseous contaminants such as hydrogen sulfide and ammonia prior to wax removal. Fractionation may be through conventional means such as expansion drums or fractionation columns.

Wax Removal Catalyst:

The wax removal catalyst may be crystalline or amorphous. Crystalline materials are molecular sieves containing at least ten or twelve ring channels and may be based on aluminosilicates (zeolites) or silica aluminates phosphates (SAPOS). The zeolites used for oxygenate treatment may contain at least one channel 10 or 12. Examples of such zeolites include ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, Ferrierite, ITQ-13, MCM-68 and MCM-71.

Examples of aluminophosphates containing at least one ring channel 10 include ECR-42. Examples of ring 12 contendochannel molecular sieves include Beta zeolite, and MCM-68. The molecular sieves are described in U.S. Patent Nos. 5,246,566, 5,282,958,4,975,177, 4,397,827, 4,585,747, 5,075,269 and 4,440,871. MCM-68 is described in USP 6,310,265. MCM-71 and ITQ-13 are described in PCT published applications WO 0242207 and WO 0078677. ECR 42 is disclosed in USP 6,303,534. Preferred catalysts include ZSM-48, ZSM-22 and ZSM-23. Especially preferred is ZSM-48. The molecular sieves, preferably, are in the form of hydrogen. The reduction may occur in situ during the wax removal stage itself or may occur ex situ elsewhere.

Amorphous wax removal catalysts include alumina, fluorinated alumina, silica alumina, fluorinated silica alumina and Group 3 metal silica alumina. Such catalysts are described, for example, in U.S. Patent Nos. 4,900,707 and 6,383. 366

The wax removal catalysts are bifunctional, i.e., loaded with a hydrogenating metal component, which is at least one Group 6 metal, at least one Group 8-10 metal, or mixtures thereof. Preferred metals are Group 9-10 metals. Especially preferred are Group 9-10 noble metals such as Pt, Pd or mixtures thereof (based on the format of the IUPAC Periodic Table having groups of 1 to 18. These metals are catalyst based 0.1 to 30% by weight The catalyst preparation and metal loading methods are described, for example, in USP 6.294.077, and include, for example, ion exchange and ionization using Metal salts that can be decomposed Metal dispersion techniques and catalyst particle size control are described in USP 5,282,958. Small departmental and well-dispersed metal catalysts are preferred.

Molecular sieves typically are composed of binder materials which are resistant to elevated temperatures and which may be used under wax removal conditions to form a finished wax removal catalyst or may be free of binder (self-binding). The binder materials are usually inorganic oxides such as silica, alumina, silica aluminas, desilyl binary combinations with other metal oxides such as titania, magnesia, thorium, zirconia and the like and tertiary combinations of such oxides such as alumina-thorium and silica-alumina. magnesia. The amount of sieviramolecular in the finished wax removal catalyst is from 10 to 100, preferably 35 to 100%, based on the catalyst. Such catalysts are formed by methods such as spray drying, extrusion and the like. The wax removal catalyst may be used in the form of sulfides or non-sulfides, and preferably in the form of sulfides.

Wax removal conditions include temperatures of 250-400 ° C, preferably 275-350 ° C, pressures from 791 to 20,786 kPa (100 to 3,000 psig), preferably 1480 to 17,339 kPa (200 to 2500 psig), hourly space velocities from zero at 10 h.sup.-1, preferably 0.1 to 5 h.sup.-l and hydrogen treatment gas ranges from 45 to 1780 m.sup.3 (250 to 10000 scfB), preferably 89 to 890 m.sup.3 / m.sup.3 (500 to 5000 scf / B).

Hydro Finish:

At least a portion of the wax removal product is passed directly to an undocking hydro-finishing step. It is preferable to hydro-finish the product resulting from the removal of wax to adjust the product qualities to the desired specifications. Hydro-finishing is a way of gently hydrotreating any olefin in the range of residual lubricants and aromatics to saturation, as well as removing any remaining heteroatoms and colored bodies. Hydro-finishing after wax removal is usually cascaded with the wax removal step. Generally, the hydro finish will be performed at temperatures of about 170 ° C to 350 ° C, preferably 180 ° C to 250 ° C. Total pressures typically range from 2859 to 20,786 kPa (about 400 to 3000 psig). The hourly space velocity is typically 0.1 to 5 LHSV (h sup.-l), preferably 0.5 to 3 h sup.-l and treatment gas ranges from 44.5 to 1780 m.sup.3 / m.sup.3 (250 to 10,000 sctfB).

Hydro-finishing catalysts are those containing Group 6 metals (based on the format of the IUPAC Periodic Table having Groups 1 to 18), Groups 8-10 metals, and mixtures thereof. Preferred metals include at least one noble metal having a strong hydrogenation function, especially platinum, palladium and mixtures thereof. Metal mixing may also be present as bulky metal catalysts, where the amount of metal is 30 wt.% Or greater with basene catalyst. Suitable metal oxide supports include low acidulation oxides such as silica, alumina, silica alumina or titania, preferably alumina. Preferred hydro-finishing catalysts for aromatic saturation will be composed of at least one metal having a relatively strong hydrogenation function on a porous support. Typical support materials include amorphous or crystalline oxide materials such as alumina, silica, and silica alumina. The metal content of the catalyst is often as high as about 20% by weight for non-noble metals. Noble metals are usually present in amounts no greater than about 1% by weight.

The hydro-finishing catalyst is preferably a mesoporous material belonging to class M41S of the catalyst family. The M41S family of catalysts are mesoporous materials having high silica esters, the preparation of which is best written in J. Amer. Chem. Soc. 1992, 114, 10,834. Examples include MCM-41, MCM-48 and MCM-50. Moresporous refers to catalysts having pore sizes from 15 to 100ANG. A preferred member of this class is MCM-41, the preparation of which is described in USP 5,098,684. MCM-41 is an inorganic, porous, layerless phase having a hexagonal arrangement of uniformly sized pores. The physical structure of the MCM-41 is like a bundle of straws where the opening of the tubes (pore cell diameter) ranges from 15 to 100 Angstroms. OMCM-48 has cubic symmetry and is described, for example, in USP5.198.203 whereas MCM-50 has a lamellar structure. The MCM-41 can be made with different sized pore openings in the porous band. Mesoporous materials may contain a metal hydrogenation component which is at least one Group 8, Group 9 or Group 10 metal. Preferred noble metals are especially Group 10 noble metals, more preferably Pt, Pd or mixtures thereof.

Generally hydro-finishing will be performed at temperatures of about 150 ° C to 350 ° C, preferably 180 ° C to 250 ° C. Total pressures typically range from 2859 to 20,786 kPa (about 400 to 3000psig). The net hourly space velocity typically was 0.1 to 5 LHSV (h. Sup.-l), preferably 0.5 to 3 h sup.-l and hydrogen treatment gas flow rates are 44.5 to 1780. m.sup.3 / m.sup.3 (250 to 10,000 scffB).

The lubricating viscosity ester will typically have a Kv at 100 ° C in the range of about 2.5 cSt to about 8.5 cSt. Typically, the Kv at 40 ° C will be from about 8 to about 92 cSt.

Typical properties are:

Stereo A51 Typical KV100 = 2.73, KV 40 = 8.9 to 9.4 cSt, Pour point = -54 ° C.

Stereo A32 KV100 = 5.1 to 5.5 cSt, KV40 = 25.5 - 29.0 cSt, pour point = -54 ° C.

Stereo P81 KV100 = 8.2 cSt, KV 40 = 81 - 92 cSt, pour point = -37 ° C.

In general, paraffin oils and esters will be mixed at a weight ratio of about 97.5: 2.5 to about 65:35, and preferably about 95: 5 to about 70:30.

Suitable esters for use in the present invention include those basic acid esters with monoalkanols and the monocarboxylic acid polyol esters. Esters of the first type include, for example, esters of dicarboxylic acids such as italic acid, succinic acid, adipic acid and the like with a variety of alcohols such as butyl, hexyl and dodecyl alcohol to name but a few.

Especially useful synthetic esters are those obtained by reacting one or more polyhydric alcohols, preferably clogged polyols (such as neopentyl polyols, for example neopentyl glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol, trimethylol propane, pentaerythritol and dipentaerythritol) with alkanoic acids containing at least about 4 carbon atoms such as C5 to C30 acids (such as straight chain saturated fatty acids including caprylic acid, capric acid, lauric acid, palmitic acid, palmitic acid, stearic acid, arachic acid, berenic acid, or the corresponding branched chain fatty acids or unsaturated fatty acids, such as oleic acid, or mixtures thereof).

Suitable synthetic ester components include detrimethylol propane esters, trimethylol butane, trimethylol ethane, pentaerythritol and / or dipentaerythritol with one or more monocarboxylic acids containing about 5 to about 10 carbon atoms. Such esters are widely and commercially available, for example, Esterex® esters sold by ExxonMobil Chemical Company.

Other esters may include natural esters and derivatives thereof, fully esterified or partially esterified, optionally with free hydroxyl or carboxyl groups. Such esters may include glycerides, modified natural and / or vegetable oils derived from fatty acids or fatty alcohols.

Performance Additives:

The present invention may be used with additional lubricating components in effective amounts in the lubricating compositions, such as polar and non-polar lubricating base oils, performance additives such as, but not limited to, ash-free metal oxidation inhibitors, metal-free dispersants. ashes, ash-free metal detergents and rust and corrosion inhibitors, metal deactivators, anti-wear agents (low-ash, non-phosphorous, sulfur-containing and non-phosphorus-containing, non-phosphorus-containing) extreme pressure (metallic and non-metallic, phosphorus-free and phosphorus-free, sulfur-free and sulfur free), anti-sequestering agents, pour point depressants, wax modifiers, peel compatibility agents, friction modifiers, lubricating agents, staining agents, chromophore agents, disposed of de-emulsifying foams and others. For a review of various commonly used additives, see Klamann in "Lubricants and Relateds Products, Verlag Chemie, Deerfield Beach, Fla .; ISBN 0-89573-177-0, which also provides a good discussion of a number of the discussed lubricant additives mentioned below. Also Reference is made to "Lubricant Additives" by MW Ranney, published by Noyes Data Corporation of Parkridge, NJ (1973). In particular, the base oils cited herein may show significant performance advantages with modern additives and / or additive systems, and additive packages that provide low sulfur, low phosphorus, and / or low ash characteristics in the formulated functional fluid. Typical adhesive quantities:

When the lubricating oil compositions contain one or more of the additives discussed above, the additives are mixed in the composition in an amount sufficient for it to perform its intended function. Typical amounts of such additives useful in the present invention are shown in table 1 below. <table> table see original document page 16 </column> </row> <table>

Examples

The properties of two paraffin oils, Mink 4 and Mink 6 used for the preparation of a base oil of the invention are compared with the properties of 2 commercially available PAOs in Table 2.

<table> table see original document page 16 </column> </row> <table>

(ASTM D5950)

Each of the oils was mixed with an ester, the amounts of which are shown in table 3. Each of the mixtures included the same lubricant additive and in the same amounts. The properties of the fully formulated oils of the invention and comparative oils are also shown in Table 3.

TABLE 3

<table> table see original document page 16 </column> </row> <table> <table> table see original document page 17 </column> </row> <table> Figure 1 graphically compares the dynamic viscosity of oil in the Example 1 of the invention with comparative oil, while Figure 2 compares the oil of Examples 2 and 3 of the invention with comparative oil 2 using test method ASTM D 5133.

Claims (6)

1. Base raw material or base oil, characterized in that it is composed of: (a) about 65 to about 97.5%, based on the weight of the base raw material or base oil of a paraffinic oil having a VI of 130 or greater, a Kv at 100 ° C of about 3.8 cSt or greater and a flow point of -15 ° C or less; and (b) about 2.5 to about 35% by weight, based on the weight of the base stock or base oil of a lubricating viscosity ester, where the base stock or base oil performs well. at low temperature as evidenced by its dynamic viscosity measured by the ASTM D5133 test method. Base material or base oil according to Claim 1, characterized in that it is additionally exempt from added viscosity demodifiers. 3. Base raw material or base oil according to Claim 2, characterized in that the paraffinic oil is produced by a process comprising: (a) hydrotreating a feedstock having a wax content of about 60%. by weight, based on feedstock, with a hydrotreating catalyst under effective hydrotreating conditions such as less than 5% by weight of the feedstock converted to products at 650 ° F (343 ° C) less to produce a hydrotreated feedstock whose VI increase is less than 4 and greater than the VI of the feedstock, (b) the fractionation of the hydrotreated feedstock to separate the gaseous product from the liquid product, (c) the hydro-removal of wax from the liquid product with A wax removal catalyst which is at least ZSM-48, ZSM-57, ZSM-- 23, ZSM-22, ZSM-35, Ferrierite, ECR-42, ITQ-13, MCM-71, MCM-68, beta , fluorinated amine, silica alumina or fluorinated silica alumina, under effective wax removal conditions where the wax removal catalyst contains at least one group 9 or group 10 metal. 4. Functional fluid composition characterized in that it is composed of the base raw material or base oil as defined in claims 1 or 3, and at least one other additive other than a viscosity modifier. 5. Method of producing a functional fluid having a high performance and good low temperature performance, evidenced by the dynamic viscosity measured by the ASTM D5133 test method, characterized in that it is composed of: mixture (i) from about 65 to about 97.5 wt.%, On a fluid weight basis, of a paraffinic oil prepared by: (a) hydrotreating a feedstock having a wax content of about 60 wt.% Based on the common feedstock catalyst feedstock. hydrotreating under effective hydrotreating conditions such that less than 5% by weight of the feedstock is converted to products at 650 ° F (343 ° C) less to produce a hydrotreated feedstock whose VI increase is less than 4%. and is larger than the VI of the feedstock; (b) the fractionation of the hydrotreated feedstock to separate the gaseous product from the liquid product; (c) the hydro-removal of wax from the liquid product with a removal catalyst. the wax which is at least ZSM-48, ZSM-57, ZSM-- 23, ZSM-22, ZSM-35, ferrierite, ECR-42, ITQ-13, MCM-71, MCM-68, beta, alumina fluorinated silica-alumina or fluorinated silica-alumina under wax removal conditions where the wax removal catalyst contains at least one Group 9 or Group 10 metal with (ii) from about 2.5 to about 35% by weight, based on the fluid base, of a lubricating viscosity ester. Method according to claim 5, characterized in that it includes the incorporation of at least one additive in addition to a viscosity modifier.