CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Patent Application No. 61/515,179 filed on August 4, 2011, the entire contents of which are hereby incorporated by reference.

BACKGROUND

[0301] This disclosure relates to a lubricant composition and to methods of manufacture thereof. This disclosure also relates to a coolant composition and to methods of manufacture thereof.

[0002] Lubricants are used in machining to reduce friction between the cutting tool and the surfaces that are being machined. Lubricants also function as coolants and carry away heat generated during machining in operations such as grinding, drilling, milling, and cutting. The quality of a lubricant greatly affects the cost of a production operation since the efficiency, service life and other aspects of performance of both the tool and the machine are affected by the quality of the lubricant. As a result, increasing demands are placed upon lubricants.

[0003] During machining, vapors from the lubricant are often emitted into the atmosphere. Lubricants used in machining are often discarded at waste management sites or discharged into the ground after usage. It is therefore desirable to use lubricants that are not detrimental to the health of living beings and are environmentally friendly in addition to improving the performance of machining operations.

SUMMARY

[0004] Disclosed herein is a lubricant composition comprising a hydrocarbon oil; inorganic particles; and molybdenum disulfide; the molybdenum disulfide being dispersed in the soybean oil.

[0005] Disclosed herein too is a lubricant composition comprising a base oil; inorganic particles; and metal disulfide particles; the metal disulfide particles being dispersed in the base oil in the presence of an electrical field and a mechanical field.

[0006] Disclosed herein too is a method comprising agitating a composition to form a lubricating composition; the composition comprising molybdenum disulfide, inorganic particles and a base oil; the agitating being conducted in the presence of a magnetic field that is greater than the earth's field, an electrical field or a combination comprising the magnetic field and the electrical field.

BRIEF DESCRIPTION OF FIGURES

[0007] The figure is a depiction of the set-up to manufacture the lubricant composition.

DETAILED DESCRIPTION

[0008] Disclosed herein is a lubricant composition that is environmentally friendly and that can significantly reduce costs by improving tool life and machine life during machining operations. The lubricant composition advantageously comprises a base oil having metal sulfide particles dispersed therein. The lubricant composition further comprises inorganic particles that have a polymer disposed thereon. The metal sulfide particles are suspended in the base oil and remain in suspension in larger amounts for significantly larger periods of time compared with other comparative lubricant compositions. Disclosed herein too is a coolant composition that comprises the lubricant composition, a surfactant and/or a soap and water.

[0009] Disclosed herein too is a method of manufacturing a lubricant composition that comprises dispersing metal disulfide particles and the coated metal oxide particles in a base oil while subjecting the lubricant composition to an electrical field, a magnetic field or a combination of an electrical and magnetic field. In one embodiment, the dispersing is accomplished by the application of shear forces to the lubricant composition while simultaneously subjecting the lubricant composition to an electrical field, a magnetic field or to a combination of an electrical field and a magnetic field. Disclosed herein too is a method of manufacturing the coolant composition.

[0010] The base oil can be an oil derived from crude, from biological products, from agricultural products, from forest products, or the like, or from a combination comprising at least one of the foregoing oils. Examples of oils derived from crude are petroleum-based oils. Examples of base oils derived from biological products are algae oil, animal fat oils and tallow, fish oils, vegetable oil, waste vegetable oil, or the like, or a combination comprising at least one of the foregoing base oils derived from biological products. Examples of oil derived from agricultural products are soybean oil, rapeseed oil (canola), castor bean oil, sunflower seed oil, peanut oil, corn oil, safflower seed oil, linseed oil, jatropha oil, or the like, or a combination comprising at least one of the foregoing oils derived from agricultural products. Examples of oils derived from forest products are apricot seed oils, mango oil, coconut oil, cashew nut oil, or the like, or a combination comprising at least one of the foregoing oils derived from forest products. In one exemplary embodiment, the base oil is soybean oil.

[0011] The soybean oil can be saturated or unsaturated. In one embodiment, the soybean oil can comprise C12 - C ₂ o saturated fatty acids. In another embodiment, the soybean oil comprises oleic acids. For example, the soybean oil can comprise 16:1 (palmitioleic acid), 18:1 (oleic acid), 18:2 (linoleic acid) and 18:3 (linolenic acid). In one embodiment, it is desirable for the soybean oil to contain up to about 85 wt% oleic acid. An exemplary soybean oil is AP-82 obtained from Cargill.

[0012] In one embodiment, the base oil has an acid value of 30 to 40, a saponification value of 190 to 199. In one embodiment, the base oil has a palmitic acid content of 3.5 to 5 weight percent, based upon the total weight of the base oil. In another embodiment, the base oil has an oleic acid content of about 40 to about 50 wt% oleic acid, and about 30 to about 40 wt% linoleic acid, based upon the total weight of the base oil.

[0013] In an exemplary embodiment, the base oil has an oleic acid content of about 42 to about 45 wt% oleic acid, and about 32 to about 35 wt% linoleic acid, based upon the total weight of the base oil.

[0014] The base oil can also be an algae oil obtained from a plant or an alga. Lipid or oil-producing algae can include a wide variety of algae, although not all algae produce sufficient oil, as mentioned above. The most common oil-producing algae can generally comprise the diatoms (bacillariophytes), green algae (chlorophytes), blue-green algae (cyanophytes), and golden-brown algae (chrysophytes). In addition, a fifth group known as haptophytes may be used. Exemplary species for extracting algal oil are Botryococcus braunii, Chlorella, Dunaliella tertiolecta, Gracilaria, Pleurochrysis carterae, Sargassum, or the like, or a combination comprising at least one of the foregoing species.

[0015] Examples of bacillariophytes capable of oil production include the genera Amphipleura, Amphora, Chaetoceros, Cyclotella, Cymbella, Fragilaria, Hantzschia, Navicula, Nitzschia, Phaeodactylum, Thalassiosira, or the like, or a combination comprising at least one of the foregoing bacillariophytes. Examples of chlorophytes capable of oil production include Ankistrodesmus, Botryococcus, Chlorella, Chlorococcum, Dunaliella, Monoraphidium, Oocystis, Scenedesmus, Tetraselmis, or the like, or a combination comprising at least one of the foregoing or the like, or a combination comprising at least one of the foregoing bacillariophytes. In one aspect, the chlorophytes can be Chlorella or Dunaliella. Specific non-limiting examples of cyanophytes capable of oil production include Oscillatoria and Synechococcus. A specific example of chrysophytes capable of oil production includes Boekelovia. Specific non-limiting examples of haptophytes include Isochrysis and Pleurochysis.

[0016] In an embodiment wherein the organism is an algae, the algae can be any from the genuses including Dunaliella, Chlorella, Nannochloropsis, or Spirulina. The organism can be Dunaliella Bardawil, Dunaliella salina, Dunaliella primolecta, Chlorella vulgaris, Chlorella emorsonii, Chlorella minutissima, Chlorella protothecoides, Chlorella sorokiniana, Chlorella vulgaris, Spirulina platensis, Cyclotella cryptica, Tetraselmis suecica, Monoraphidium, Botryococcus braunii, Stichococcus, Haematococcus pluvialis, Phaeodactylum tricornutum, Tetraselmis suecica, Isochrysis galbana, Nannochloropsis, Nitzschia closterium, Phaeodactylum tricornutum, Chlamydomas perigranulata, Synechocystisf, Tagetes erecta, Tagetes patula.

[0017] The metal sulfide particles can be molybdenum disulfide, antimony trisulfide, antimony pentasulfide, or the like, or a combination comprising at least one of the foregoing metal sulfides. An exemplary metal sulfide is molybdenum disulfide (M0S ₂ ). An exemplary molybdenum disulfide is Tech Fine Grade M0S ₂ that is commercially available from Rose Mill Company.

[0018] It is desirable for the metal sulfide particles to have an average particle size of up to about 6 micrometers prior to dispersion. In one embodiment, the metal sulfide particles have an average particle size of about 0.1 micrometers to about 5.5 micrometers after dispersion. In another embodiment, the metal sulfide particles have an average particle size of about 0.5 to about 5.0 micrometers after dispersion. In yet another embodiment, the metal sulfide particles have an average particle size of about 1.0 to about 4.0 micrometers after dispersion.

[0019] In one embodiment, it is desirable for the metal sulfide particles to have a minimum particle size that is greater than or equal to about 1.0 micrometer after dispersion. In another embodiment, it is desirable for the metal sulfide particles to have a minimum particle size that is greater than or equal to about 2.0 micrometers after dispersion. In yet another embodiment, it is desirable for the metal sulfide particles to have an average particle size of greater than or equal to about 3.0 micrometers after dispersion.

[0020] The metal sulfide particles may have particle sizes in the nanometer range. In one embodiment, it is desirable for the metal sulfide particles to be less than or equal to about 100 nanometers after dispersion. In another embodiment, it is desirable for the metal sulfide particles to be less than or equal to about 75 nanometers after dispersion. In yet another embodiment, it is desirable for the metal sulfide particle sizes to be less than or equal to about 50 nanometers after dispersion. In yet another embodiment, it is desirable for the metal sulfide particle sizes to be less than or equal to about 10 nanometers after dispersion.

[0021] It is desirable for the lubricant composition to contain the metal sulfide in an amount of about 0.1 pounds (lbs) to about 4 lbs per 11 gallons of the base oil. In one embodiment, the metal sulfide is present in an amount of about 0.5 to about 3 lbs per 11 gallons of the base oil. In another embodiment, the metal sulfide is present in an amount of about 0.8 to about 2.0 lbs per gallon of the base oil. In an exemplary embodiment, the metal sulfide is present in an amount of about 1.0 lbs per gallon of the base oil.

[0022] As noted above, the lubricant composition further comprises inorganic particles having a polymer disposed thereon. In one embodiment, the inorganic particles are low density ceramic particles that have a polymer disposed thereon. In another embodiment, the inorganic particles are coated with a polymer but are not covalently or ionically bonded to the inorganic particles. In other words, the polymer is physically adsorbed onto the inorganic particles.

[0023] In another embodiment, the inorganic particles are covalently bonded to the polymers. In yet another embodiment, the inorganic particles are ionically bonded to the polymers. In yet another embodiment, the inorganic particles are hydrogen bonded to the polymers.

[0024] The inorganic particles are low density inorganic particles and have densities of about 0.5 to about 3 grams per cubic centimeter, specifically about 1.0 to about 2.5 grams per cubic centimeter, and more specifically about 1.4 to about 2.3 grams per cubic centimeter prior to having the polymer disposed thereon. The inorganic particles have surface areas of about 50 to about 300 square meters per gram, specifically about 75 to about 250 square meters per gram, and more specifically about 100 to about 200 square meters per gram.

[0025] Examples of suitable inorganic particles are inorganic oxides, metal oxides, inorganic nitrides, metal nitrides, inorganic oxynitrides, metal oxynitrides, inorganic carbides, metal carbides, inorganic borides, metal borides, or the like, or a combination comprising at least one of the foregoing inorganic particles.

[0026] Exemplary inorganic particles are inorganic oxides and metal oxides. Exemplary inorganic oxides are silicon dioxides. Exemplary silicon dioxides are fumed silica. In particular, the incorporation of surface modified, hydrophobic fumed silica versions impart significant improvements in both lubricant stability and thermal properties. Exemplary metal oxides are aluminum oxide, zirconium oxide, titanium dioxide, cerium oxide, or the like, or a combination comprising at least one of the foregoing metal oxides.

[0027] The inorganic particles have average particle sizes of about 5 to about 250 nanometers, specifically about 20 to about 150 nanometers, and more specifically about 40 to about 120 nanometers. The average particle sizes are determined by the radius of gyration of the particles.

[0028] The inorganic particles have a polymer disposed upon them. The polymer can be physically adsorbed, covalently bonded, ionically bonded, or hydrogen bonded to the inorganic particles. The polymers can be oligomers, homopolymers, block copolymers, dendrimers, ionomers, polyelectrolytes, or the like, or a combination comprising at least one of the foregoing polymers. The polymers can be thermoplastic polymers or crosslinked polymers.

[0029] The thermoplastic polymer may also be a blend of polymers, copolymers, terpolymers, or combinations comprising at least one of the foregoing thermoplastic polymers. The thermoplastic polymer can also be an oligomer, a homopolymer, a copolymer, a block copolymer, an alternating block copolymer, a random polymer, a random copolymer, a random block copolymer, a graft copolymer, a star block copolymer, a dendrimer, or the like, or a combination comprising at last one of the foregoing thermoplastic polymers.

[0030] Examples of the thermoplastic polymers are polyacetals, polyolefins, polyacrylics, polycarbonates, polystyrenes, polyesters, polyamides, polyamideimides, polyarylates, polyarylsulfones, polyethersulfones, polyphenylene sulfides, polyvinyl chlorides, polysulfones, polyimides, polyetherimides, polytetrafluoroethylenes, polyetherketones, polyether etherketones, polyether ketone ketones, polybenzoxazoles, polyphthalides, polyacetals, polyanhydrides, polyvinyl ethers, polyvinyl thioethers, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polysilazanes, styrene acrylonitrile, acrylonitrile-butadiene-styrene (ABS), polyethylene terephthalate, polybutylene terephthalate, polyurethane, ethylene propylene diene rubber (EPR), polytetrafluoroethylene, fluorinated ethylene propylene, perfluoroalkoxyethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polysiloxanes, or the like, or a combination comprising at least one of the foregoing thermoplastic polymers. Exemplary polymers are polysiloxanes. [0031] Exemplary polysiloxanes are polydialklylsiloxanes, polydiarylsiloxanes, polyalkylarylsiloxanes, or the like, or a combination comprising at least one of the foregoing polysiloxanes. Exemplary polydialkylsiloxanes are polydimethylsiloxanes.

[0032] It is desirable for the polymers to have a molecular weight of about 200 to about 5,000 grams per mole, specifically about 300 to about 2,000 grams per mole, and more specifically about 400 to about 1,500 grams per mole.

[0033] The inorganic particles are added in amounts of about 0.5 to about 20 weight percent, based on the total weight of the lubricant composition. In an exemplary embodiment, the inorganic particles are added in amounts of about 1 to about 10 weight percent, based on the total weight of the lubricant composition. An exemplary inorganic particle is CAB-O-SIL ^® TS-720 commercially available from Cabot Corporation.

[0034] In one method of manufacturing the lubricant, the base oil is mixed with the metal sulfide in reactor to which is applied a magnetic field, an electric field or a combination of a magnetic field and an electrical field. The base oil is disposed in a reactor. The metal sulfide is added to the reactor gradually while the contents of the reactor are being agitated. The inorganic particles can then be added to the reactor. In an exemplary embodiment, a magnetic field and an electrical field are applied to the reactor during the agitation. The agitation is conducted for a period of about 1 minute to about 120 minutes. In one embodiment, the agitation can be achieved with a stirrer. In another embodiment, ultrasonic agitation can be used.

[0035] In one embodiment, the reactor is a 55 gallon drum. When the reactor is a 55 gallon drum, the metal sulfide and the inorganic particles are added to the base oil over a period of about 5 to about 35 minutes, specifically over a period of about 20 minutes. The stirring in the 55 gallon drum is conducted for a period of about 20 minutes beginning with the first addition of the metal sulfide to the 55 gallon drum.

[0036] The magnetic field is generally applied using regular magnets or electromagnets. The magnets are generally applied to the outside of the reactor, though they can be applied to the inside of the reactor as well. The magnetic field applied across the reactor generally has a strength greater than the earth's magnetic field. The magnetic field has a strength of greater than or equal to about 3,000 gauss, preferably greater than or equal to about 6,000 gauss, preferably greater than or equal to about 9,000 gauss, preferably greater than or equal to about 12,000 gauss, and more preferably greater than or equal to about 20,000 gauss. [0037] An electric field is also applied to the drum during the mixing of the base oil with the metal sulfide. The electric field can be applied using either a direct current (DC) voltage or using an alternating current (AC) voltage. In an exemplary embodiment, the electric field is applied using a DC voltage. The electric field is applied by placing the positive electrode in the reactor while the negative electrode is generally applied to the surface of the reactor.

[0038] The electric field is generally applied using a voltage of greater than or equal to about 3 volts, preferably greater than or equal to about 6 volts, preferably greater than or equal to about 9 volts and more preferably greater than or equal to about 12 volts.

[0039] It is generally desirable for the electrical field and the magnetic field to be applied simultaneously. However, they may also be applied sequentially if desired. Thus the electrical field can be applied prior to applying the magnetic field or vice versa. In one embodiment, only an electrical field may be applied to reactor.

[0040] The lubricant composition thus made does not show any separation of the metal sulfide from the base oil for a period of greater than or equal to about 2 weeks, preferably greater than or equal to about 4 weeks, and more preferably greater than or equal to about 2 months. A lubricant composition manufactured by using an electrical field and a mechanical field displays a superior shelf-life performance when compared with lubricant compositions manufactured using only a magnetic field. In addition, lubricant compositions manufactured using both an electrical field and a magnetic field display superior lubricating properties during machining. Tool performance and machine performance is significantly enhanced when compared with tool and machine performance attained when using a lubricant composition that is manufactured by using only a magnetic field during the agitation.

[0041] The lubricant composition can also advantageously be converted to a coolant by adding water and a surfactant and/or a soap to the lubricant composition. The coolant is used to cool machine tools and machined components during the machining operation.

[0042] A variety of surfactants may be used. Examples of suitable surfactants are anionic surfactants, cationic surfactants, non-ionic surfactants, zwitterionic surfactants, or a combination comprising at least one of the foregoing surfactants.

[0043] In one embodiment, soap can be added to the lubricant composition to produce the coolant. The soap can be commercially available hand soap. A suitable example of a hand soap is Tackle Hand Cleaner commercially available from E-Z Way Products in Waterbury Connecticut. [0044] The soap is generally added in an amount of about 0.01 to about 5 gallons per gallon of the lubricant composition. In one embodiment, the hand soap is added in an amount of about 0.1 to about 4.5 gallons per gallon of the lubricant composition. In another embodiment, the hand soap is added in an amount of about 0.2 to about 3 gallons per gallon of the lubricant composition.

[0045] The water is added in an amount of about 0.01 to about 50 gallons per gallon of the lubricant composition. In one embodiment, the water is added in an amount of about 0.1 to about 45 gallons per gallon of the lubricant composition. In another embodiment, the water is added in an amount of about 0.5 to about 40 gallons per gallon of the lubricant composition. It is to be noted that the water along with the soap and/or surfactant can be added at the source or alternatively, the lubricant composition and the water along with the soap and/or surfactant added later.

[0046] In one embodiment, the water and soap are added to the lubricant composition in a drum. During the addition, the contents of the drum are agitated to produce the coolant. The coolant thus manufactured can be stored for extended periods of time and used when desired.

[0047] The following examples, which are meant to be exemplary, not limiting, illustrate compositions and methods of manufacturing of some of the various embodiments of the lubricant compositions described herein.

[0048] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention.