JP2008536955A - Metal working fluid - Google Patents

Abstract

Evaporation loss of metal working fluid in high speed machining is avoided.
The present invention relates to a metal working fluid comprising a base oil having a viscosity index according to ASTM D2270 of greater than 110 and a pour point according to ASTM D97 of less than -40 ° C. The base oil is preferably a Fischer-Tropsch derived oil, the kinematic viscosity at 100 ° C. of the base oil according to ASTM D445 is preferably 2-3 mm ² / sec, and the flash point of the base oil according to ASTM D92 is preferably above 170 ° C. More preferably, it exceeds 175 ° C, and most preferably it exceeds 180 ° C.
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Description

  The present invention relates to a metal working fluid containing a base oil and one or more additives. The invention further relates to a method of using the metal working fluid as a metal working fluid, particularly for high speed machining.

  Metalworking fluids are actually well known and are used in metalworking such as cutting, grinding, rolling, stretching and forging. In this regard, D.C. See Klamann, “Lubricants and related products”, Verlag Chemie GmbH, Weinheim, Germany, 1984, p351-383 (which is incorporated herein by reference). An example of a metal working fluid (or “cutting oil”) is described in US Pat. No. 5,958,849.

A problem with known metal working fluids is that the base oil forming part tends to evaporate very quickly, thus possibly damaging the metal working gear. This problem is even more relevant to high speed machining and promotes evaporation of the metal working fluid as a result of higher working temperatures. High speed machining is a well-known term in the technical field of metalworking. Examples of equipment used for high speed machining are described in US20050254937 and US-A-5072948.
US-A-5958849 US20050254937 US-A-5072948 EP-A-7769595 EP-A-6683426 US-A-4943672 US-A-5059299 WO-A-9934917 WO-A-9207720 WO-A-9410264 EP-A-0582347 WO-A-9220759 WO-A-9201657 US-A-20040065581 D. Klamann, “Lubricants and related products”, Verlag Chemie GmbH, Weinheim, Germany, 1984, p351-383. Ryland, Lloyd B.E. , Tamale, M .; W. And Wilson, J .; N. , Cracking Catalysts, Catalysis; Volume VII, edited by Paul H. Emmet, Reinhold Publishing Corporation, New York, 1960, pp. 5-9

The object of the present invention is to avoid or at least minimize the above problems.
It is a further object of the present invention to provide an alternative metal working fluid.

One or more of the above and other objects is to provide a metal working fluid containing a base oil having a viscosity index of more than 110 according to ASTM D2270 and a pour point of less than −40 ° C. according to ASTM D97, according to the present invention. Is achieved.
The present invention is also directed to a method of using the metal working fluid for high speed machining.

Applicants have surprisingly found that base oils having the above properties can be blended into metal working fluids that exhibit superior evaporation losses at different temperatures, thereby improving the properties compared to known metal working fluids. A further advantage of the present invention is that metal working fluids containing base oils with specified properties exhibit a relatively high flash point, thus improving safety during use of the metal working fluid. According to the present invention, a metal working fluid having a flash point (according to ASTM D92) exceeding 170 ° C. is obtained.
Yet another advantage of the present invention is that a specified base oil for blending into a metal working fluid according to the present invention provides a substantially chloride-free and non-emulsifiable finished metal working fluid. It is. The metal working fluid may contain one or more additives.

  This property makes the metal working fluid particularly suitable for high speed machining. The present invention relates to a method of using the metal working fluid composition according to the invention as a metal working fluid, especially for high speed machining, i.e. for high speed machining of more than 8000 revolutions per minute, preferably more than 10,000 revolutions. The rotary machine includes a hollow shaft and a machine tool loaded on the shaft, and the metal working fluid can flow to the machine tool through the hollow shaft.

  The present invention is also directed to a high-speed grinding operation in which a grinding operation is performed using a grinding wheel at a speed exceeding 50 to 200 m / second, more preferably exceeding 100 m / second. This speed is defined as the relative speed between the grinding wheel and the metal object to be machined on its contact point. This upper speed limit depends on the design of the device in which it is desired to achieve high speed. Currently this value is less than 200 m / s, but higher speeds are expected for future machines.

  The invention is also directed to high speed machining performed with a cutting tool, for example in the case of reamer finishing, turning and milling. High speed operation depends on the type of material used and can range from 50 to 10,000 m / min. The cutting speed when the operation is defined as high speed machining depends on the type of material being machined. High speed machining is over 2000 m / min for polymeric materials and aluminum, over 1000 m / min for bronze, over 900 m / min for cast iron, over 700 m / min for steel, over 200 m / min for titanium, Moreover, it exceeds 60 m / min in a nickel base alloy.

The metal working fluid is preferably supplied to the high speed rotating machine at a pressure exceeding 15 bar, preferably 20-60 bar. This pressure is necessary for the metal working fluid to flow, for example, in the hollow shaft at the desired high speed.
Those skilled in the art will understand what the term “base oil” means. The base oil used in the present invention is obtained by hydroisomerization of paraffin wax, preferably followed by some type of dewaxing such as solvent or catalytic dewaxing. As the paraffin wax, Fischer-Tropsch derived wax is preferred because of its high purity and high paraffin content. Base oils obtained from Fischer-Tropsch wax are further advantageous, especially because they are free of aromatics, have no detectable odor, and have a clear, colorless color as represented by ASTM D156.

Examples of Fischer-Tropsch processes that can be used, for example, to produce the aforementioned Fischer-Tropsch derived base oils are the so-called Sasol commercial slurry phase distillate technology, the Shell middle distillate process and the “AGC-21” Exxon Mobil process. These and other methods are described in further detail, for example, in EP-A-776959, EP-A-668342, US-A-44933672, US-A-5059299, WO-A-9934917 and WO-A-9990720. ing. Typically, these Fischer-Tropsch synthesis products contain hydrocarbons having 1 to 100 and even more than 100 carbon atoms. This hydrocarbon product contains normal paraffins, isoparaffins, oxygenated products and unsaturated products. If the base oil is one of the desired isoparaffinic products, it may be advantageous to use a relatively heavy Fischer-Tropsch derived feed. The relatively heavy Fischer-Tropsch derived raw material contains a compound having 30 or more carbon atoms in an amount of 30% by weight or more, preferably 50% by weight or more, and more preferably 55% by weight or more. Further, the weight ratio of the compound having 60 or more carbon atoms and the compound having 30 or more carbon atoms in the Fischer-Tropsch derived raw material is at least 0.2, preferably at least 0.4, more preferably at least 0.55. is there. Preferably, the Fischer-Tropsch derived feed has an ASF-α value (Anderson-Schulz-Flory chain growth factor) of at least 0.925, preferably at least 0.935, more preferably at least 0.945, and even more preferably at least 0 Contains 955 C ₂₀ + fractions. Such Fischer-Tropsch derived feeds can be obtained by any method that produces a relatively heavy Fischer-Tropsch product as described above. Not all Fischer-Tropsch processes necessarily produce such heavy products. An example of a suitable Fischer-Tropsch process is described in WO-A-9934917.

  Fischer-Tropsch products contain no or only trace amounts of compounds containing sulfur and nitrogen. This is normal for the derived products of the Fischer-Tropsch reaction using synthesis gas containing almost no impurities. In general, the sulfur and nitrogen levels are below the detection limit of 5 ppm for sulfur and 1 ppm for nitrogen.

This process generally comprises a Fischer-Tropsch synthesis, a hydroisomerization step and optionally a pour point depressing step. Here, the hydroisomerization step and the optional pour point depressing step are:
(A) hydrocracking / hydroisomerizing the Fischer-Tropsch product;
(B) separating the product of step (a) into one or more distillate fuel fractions and a base oil fraction;
Is done.
Optionally, the pour point of the base oil is lowered in step (c) to obtain a base oil having a preferred low pour point by solvent dewaxing or preferably catalytic dewaxing of the oil obtained in step (b).

  The hydroconversion / hydroisomerization reaction in step (a) is preferably performed in the presence of hydrogen and a catalyst. The catalyst can be selected from those known to those skilled in the art as being suitable for this reaction. Some catalysts are described in detail below. Such a catalyst may in principle be any catalyst known in the art as suitable for isomerization of paraffin molecules in the art. Generally suitable hydroconversion / hydroisomerization catalysts are refractory such as amorphous silica-alumina (ASA), alumina, fluorided alumina, molecular sieve (zeolite) or mixtures of two or more thereof. A catalyst having a hydrogenation component supported on an oxide support. A preferred type of catalyst applied to the hydroconversion / hydroisomerization process of the present invention is a hydroconversion / hydroisomerization catalyst comprising platinum and / or palladium as a hydrogenation component. A highly preferred hydroconversion catalyst is comprised of platinum and palladium supported on an amorphous silica-alumina (ASA) support. Platinum and / or palladium is preferably present as 0.1 to 5.0% by weight, more preferably 0.2 to 2.0% by weight, calculated as an element with respect to the total weight of the support. When both are present, the weight ratio of platinum to palladium (calculated as an element) may vary within wide limits, but is preferably 0.05 to 10, more preferably 0.1 to 5. It is a range. Examples of suitable noble metals on ASA catalysts are disclosed, for example, in WO-A-9410264 and EP-A-0582347. Other suitable noble metal-based catalysts such as platinum on fluorinated alumina supports are disclosed, for example, in the aforementioned US-A-5059299 and WO-A-9220759.

  A suitable second type hydroconversion catalyst comprises at least one Group VIB metal, preferably tungsten and / or molybdenum, and at least one Group VIII non-noble metal, preferably nickel and / or cobalt. It is a catalyst containing as a hydrogenation component. Usually, both metals are present in oxides, sulfides or combinations thereof. The Group VIB metal is preferably present in an amount of 1-35 wt%, more preferably 5-30 wt%, calculated as an element with respect to the total weight of the catalyst. The Group VIII non-noble metal is suitably present in an amount of 1 to 25% by weight, preferably 2 to 15% by weight, calculated as an element relative to the total weight of the support. This type of hydroconversion catalyst which has been found to be particularly suitable is a catalyst comprising nickel and tungsten supported on aluminum fluoride.

  The non-noble metal-based catalyst is preferably used in the form of a sulfide. During use, some sulfur needs to be present in the feedstock to maintain the sulfide form. Sulfur is preferably present in the raw material at 10 ppm or more, more preferably 50 to 150 ppm.

Preferred catalysts that can be used in non-sulfide form are constructed by supporting a Group VIII non-noble metal, such as iron, nickel, on an acidic support in conjunction with a Group IB metal, such as copper. In order to suppress hydrogenolysis of paraffin to methane, copper is preferably present. The pore volume of this catalyst is preferably in the range of 0.35 to 1.10 ml / g as measured by the water absorption method, and the surface area is preferably 200 to 500 m ² / g as measured by the BET nitrogen adsorption method. The bulk density is 0.4 to 1.0 g / ml. The catalyst support is preferably amorphous silica-alumina in which alumina is present in a wide range of 5 to 96% by weight, preferably 20 to 85% by weight. The silica content as SiO ₂ is 15 to 80% by weight. The support may also contain a binder such as alumina, silica, Group IVA metal oxide, various clays, magnesia, etc., preferably a small amount of alumina or silica, for example 20-30 wt%.

For the preparation of amorphous silica-alumina microspheres, see Ryland, Lloyd B. et al. , Tamale, M .; W. And Wilson, J .; N. , Cracking Catalysts, Catalysis; Volume VII, edited by Paul H. Emmet, Reinhold Publishing Corporation, New York, 1960, pp. 5-9.
The catalyst is produced by simultaneously impregnating these metals from a solution onto a support, drying at 100 to 150 ° C, and then calcining in air at 200 to 550 ° C. The Group VIII metal is present in an amount up to about 15% by weight, preferably 1-12% by weight, while the Group IB metal is usually less than this, for example 1: 2 relative to the Group VIII metal. Present in an amount of about 1:20 by weight.

Typical catalysts are shown below.
Ni, wt% 2.5-3.5
Cu, wt% 0.25 to 0.35
Al ₂ O ₃ —SiO ₂ wt% 65 to 75
Al ₂ O ₃ (binder) wt% 25-30
Surface area 290-325 m ² / g
Pore volume (Hg) 0.35 to 0.45 ml / g
Bulk density 0.58 to 0.68 g / ml

  Another type of suitable hydroconversion catalyst is a catalyst based on a zeolitic material, suitably a zeolitic material containing at least one Group VIII metal component, preferably Pt and / or Pd as the hydrogenation component. is there. Suitable zeolitic materials and other aluminosilicates include zeolite β, zeolite Y, ultrastable Y, ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48, MCM-68, ZSM-35, SSZ-32, ferrierite, mordenite, and silica-aluminophosphates such as SAPO-11, SAPO-31. Examples of suitable hydroconversion / hydroisomerization catalysts are described, for example, in WO-A-9201657. Combinations of these catalysts are also possible. A very suitable hydroconversion / hydroisomerization process is the first step using a zeolite β-based catalyst, and ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-48, MCM-68, A process comprising a second step using a catalyst based on ZSM-35, SSZ-32, ferrierite or mordenite. Of the latter group, ZSM-22, ZSM-23 and ZSM-48 are preferred. Such a method is described in US-A-20040065581 and discloses a first step catalyst comprising platinum and zeolite beta and a second step catalyst comprising platinum and ZSM-48.

  In step (a), the raw material is contacted with hydrogen in the presence of a catalyst under high temperature and pressure. The temperature is usually in the range of 175 to 380 ° C, preferably higher than 250 ° C, more preferably 300 to 370 ° C. The pressure is usually in the range from 10 to 250 bar, preferably from 20 to 80 bar. Hydrogen can be supplied at a gas hourly space velocity of 100-10000 Nl / l / hr, preferably 500-5000 Nl / l / hr. The hydrocarbon feed may be fed at an hourly space velocity of 0.1 to 5 kg / l / hr, preferably more than 0.5 kg / l / hr, more preferably less than 2 kg / l / hr. The ratio of hydrogen to hydrocarbon feedstock can range from 100 to 5000 Nl / kg, preferably 250 to 2500 Nl / kg.

  The conversion in step (a), defined as the weight percent of feedstock having a boiling point higher than 370 ° C. per pass, reacts to a fraction having a boiling point lower than 370 ° C. is preferably at least 20% by weight, More preferably it is at least 25% by weight, preferably 80% by weight or less, more preferably 65% by weight or less. The feedstock used in the above definition is the total hydrocarbon feedstock of step (a) and thus includes the optional recycle of the high boiling fraction as obtained in step (b).

  In step (b), the product of step (a) is preferably separated into one or more distillate fuel fractions and a base oil or base oil precursor fraction having the desired viscosity characteristics. If the pour point is not within the desired range, the pour point of the base oil is further lowered by the dewaxing step (c), preferably catalytic dewaxing. In such embodiments, it may be more advantageous to dewax a wide boiling range fraction of the product of step (a). A base oil having the desired viscosity can then be advantageously isolated from the resulting dewaxed product by distillation. The final boiling point of the raw material of the dewaxing step (c) may be less than or equal to the final boiling point of the product of the step (a).

In a preferred embodiment of the invention, the viscosity index of the base oil is greater than 115, advantageously greater than 120, preferably greater than 125, more preferably less than 140, most preferably 115 to 140. Moreover, the pour point of base oil is less than -50 degreeC. Moreover, kinematic viscosity at 100 ° C. of the base oil according to ASTM D445 is preferably 1 to 4 mm ² / sec, preferably 2 to 3 mm ² / sec. The result is an even more advantageous flash point and evaporation loss value.

It is particularly preferred that the flash point of the base oil according to ASTM D92 is above 170 ° C, preferably above 175 ° C, most preferably above 180 ° C.
Furthermore, the Noack volatilization loss at 150 ° C. of the base oil by CEC L40 A93 (modified) is preferably less than 4, preferably less than 3, and most preferably less than 2.

The base oil δFBP-IBP (distillation range between the initial boiling point IBP and the final boiling point FBP measured by ASTM D2887) used in the present invention is less than 150 ° C, preferably less than 130 ° C, more preferably less than 120 ° C. It is preferable.
Furthermore, in the present invention, the δ distillation value (95 wt% -5 wt%) of the base oil according to ASTM D2888 is preferably less than 130 ° C, preferably less than 100 ° C, and still more preferably less than 95 ° C.

  Those skilled in the art will readily appreciate that various additives such as antioxidants, anti-fogging agents, metal deactivators, and dyes can be added to the metal working fluid of the present invention. Examples of suitable additives are those described in D.A. See Klamann, “Lubricants and related products”. The ester compound is preferably present in an amount of 1 to 15% by weight. Suitable ester compounds are rapeseed oil and pentaerythritol esters. It is preferred that the sulfur-containing compound is present in an amount of 0.5 to 10% by weight. Suitable sulfur-containing compounds are sulfurized esters and polysulfurs.

The metal working fluid of the present invention contains a variety of different base oils, such as mineral oils, polyalphaolefins, esters, polyalkylenes, alkylated aromatics, hydrocrackates, solvent refining groups or mixtures thereof. Good. However, the metal working fluid preferably contains a base oil that meets the requirements of claim 1 in an amount of 80% by weight or more of the base oil. It is even more preferred that the base oil component is a base oil that exclusively meets the requirements of claim 1. Even more preferably, the base oil component is actually the Fischer-Tropsch derived base oil alone described above. Practically means that the improved properties of metal working fluids are achieved with this base oil. More particularly, practically means that 95-100% by weight of the base oil, most particularly 100% by weight of the base oil, is a Fischer-Tropsch derived base oil.
The invention is further illustrated by the following non-limiting examples.

Example 1
A Fischer-Tropsch derived distillation fraction having the properties shown in Table 1 was isolated from the residue "R" obtained according to Example 1 of EP-A-1366135. After solvent dewaxing at a dewaxing temperature of −27 ° C., the measured wax content was 27.1% by weight.

  The above distillate fraction was contacted with a dewaxing catalyst consisting of 0.7 wt% platinum, ZSM-12 = 25 wt% and a silica binder. The dewaxing conditions were 40 bar hydrogen, WHSV = 1.0 kg / l. h, hydrogen gas speed 500 Nl / kg raw material, temperature 315 ° C. A base oil fraction having the properties shown in Table 2 was isolated from the dewaxed oil by distillation.

Example 2
A Fischer-Tropsch derived base oil of the present invention was further obtained in the same manner as in Example 1, except that a slightly different distillation fraction was isolated. Table 2 shows the characteristics of the base oil obtained in Example 2.

Comparative Example For comparison, commercial base oil: HVI 40 (Shell, obtained from Petit Couronne, France); HMVIP 40 (obtained from Shell, Hamburg, Germany); Ultra S2 (S-Oil Corporation, Seoul, Korea) ); And Shipmet (from SIP Ltd., London, UK) were measured and are shown in Table 2.
As can be seen from Table 2, the base oil of the present invention showed excellent flash point and excellent evaporation loss at different temperatures.

Example 3
Several metal working fluid compositions were prepared using at least 80% by weight of the base oils of Examples 1 and 2 and standard additives. The metal working fluid of the present invention showed excellent flash point and excellent evaporation loss at different temperatures.

Claims (16)

  A metal working fluid containing a base oil having a viscosity index of more than 110 according to ASTM D2270 and a pour point of less than −40 ° C. according to ASTM D97.   The metal working fluid according to claim 1, wherein the base oil is a Fischer-Tropsch derived oil.   The metal working fluid according to claim 1 or 2, wherein the base oil has a viscosity index exceeding 115, preferably 115 to 140.   The metal working fluid according to any one of claims 1 to 3, wherein the pour point of the base oil is less than -50 ° C. Kinematic viscosity at 100 ° C. of the base oil according to ASTM D445 is, 1 to 4 mm ² / sec, preferably 2 to 3 mm ² / sec at metal working fluid according to any one or more of claims 1 to 4,.   The metal working fluid according to any one or more of claims 1 to 5, wherein the flash point of the base oil according to ASTM D92 exceeds 170 ° C, preferably exceeds 175 ° C, and most preferably exceeds 180 ° C.   The metal working fluid according to any one or more of claims 1 to 6, wherein the Noack volatilization loss of the base oil at 150 ° C is less than 4, preferably less than 3, and most preferably less than 2.   8. A base oil having a δ distillation value (95% to 5% by weight) measured according to ASTM D2888 of less than 130 ° C., preferably less than 100 ° C., and even more preferably less than 95 ° C. Metal working fluid according to item or above.   The base oil (a) hydrocracking / hydroisomerizing the Fischer-Tropsch product, (b) separating the product of step (a) into one or more fuel fractions and a base oil fraction. The metal working fluid according to claim 1, which is obtained by a process.   The metal working fluid according to claim 9, wherein the base oil is obtained by performing a dewaxing step (c) on a fraction having a boiling point exceeding 350 ° C obtained in the step (b).   The metal working fluid according to claim 1, wherein the metal working fluid contains one or more additives.   The metal working fluid according to claim 11, wherein the metal working fluid contains 80% by weight or more of a base oil that meets the criteria of claim 1.   A method of using the metal working fluid according to claim 1 as a metal working fluid, especially for high speed machining.   A high-speed rotating machine including a rotatable hollow shaft and loaded with a machine tool on the hollow shaft, wherein the metal working fluid according to any one of claims 1 to 12 is a hollow shaft of the high-speed rotating machine. A metalworking method in which the high speed rotating machine flowing through to a machine tool is operated at a speed in excess of 8000 revolutions per minute (RPM).   The metal working method according to claim 14, wherein the metal working method is a high-speed grinding operation in which a grinding operation is performed using a grinding wheel at a speed of 50 to 200 m / sec. The metal working method according to claim 14 or 15, wherein the metal working fluid is supplied to the high-speed rotating machine at a pressure of 20 to 60 bar.